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USE OF THE SWAT MODEL TO EVALUATE THE IMPACT OF LAND-USE CHANGE ON EBONYI RIVER WATERSHED BY OGBU, KINGSLEY NNAEMEKA PG/M.ENG/08/48464 A PROJECT REPORT SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE AWARD OF THE DEGREE OF MASTER OF ENGINEERING (M. ENG) IN AGRICULTURAL AND BIORESOURCES ENGINEERING DEPARTMENT OF AGRICULTURAL AND BIORESOURCES ENGINEERING UNIVERSITY OF NIGERIA, NSUKKA DECEMBER, 2010

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Page 1: USE OF THE SWAT MODEL TO EVALUATE THE IMPACT OF LAND …

USE OF THE SWAT MODEL TO EVALUATE THE IMPACT OF

LAND-USE CHANGE ON EBONYI RIVER WATERSHED

BY

OGBU, KINGSLEY NNAEMEKA

PG/M.ENG/08/48464

A PROJECT REPORT SUBMITTED IN PARTIAL FULFILMENT OF

THE REQUIREMENTS FOR THE AWARD OF THE DEGREE OF MASTER

OF ENGINEERING (M. ENG) IN AGRICULTURAL AND BIORESOURCES

ENGINEERING

DEPARTMENT OF AGRICULTURAL AND BIORESOURCES

ENGINEERING

UNIVERSITY OF NIGERIA, NSUKKA

DECEMBER, 2010

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APPROVAL

USE OF THE SWAT MODEL TO EVALUATE THE IMPACT OF LAND-USE

CHANGE ON EBONYI RIVER WATERSHED

BY

OGBU, KINGSLEY NNAEMEKA

PG/M.ENG/08/48464

A PROJECT REPORT SUBMITTED IN PARTIAL FULFILMENT OF

THE REQUIREMENTS FOR THE AWARD OF THE DEGREE

OF MASTER OF ENGINEERING (M. ENG) IN

AGRICULTURAL AND BIORESOURCES ENGINEERING

DEPARTMENT OF AGRICULTURAL AND BIORESOURCES

ENGINEERING

UNIVERSITY OF NIGERIA, NSUKKA

PROJECT ADVISER:

Engr. Dr. C. C. Mbajiorgu ..……………………..…………….

EXTERNAL EXAMINER: .……………………...…………….

Engr. Prof. C.D. Okereke

HEAD OF DEPARTMENT:

Engr. Dr. B. O. Ugwuishiwu ...…………………….…………….

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DEDICATION

To my parents, Mr. & Mrs. S.O. Ogbu and my siblings, for their affection, love and

generous moral and financial support throughout the duration of this programme.

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ACKNOWLEDGMENT

I hereby express my profound gratitude to my project adviser, Engr. Dr. C. C.

Mbajiorgu for his patience, guidance, support and encouragement throughout the

duration of this programme. I also acknowledge the online contributions of; Prof.

Raghavan Srinivasan (Director of the Spatial Science Laboratory, Texas Agricultural

& Mechanical University, USA), Chris George (International Institute for Software

Technology, United Nations University, Macoa) and Nancy Sammons (United State

Department of Agriculture – Agricultural Research Service) for their immeasurable

assistance in using MapWindow-SWAT (MWSWAT) model.

I am indebted to my colleagues in Eco-Hydrological System Research Unit

(EHSRU), University of Nigeria, Nsukka for their useful assistance and motivation in

this project work. I am highly indebted to all the lecturers in the Department of

Agricultural and Bioresources Engineering, who in various ways assisted me in the

course of this study. Immense contribution of the MapWindow GIS team in providing

all the datasets required for this study is highly appreciated.

I thank my immediate family members and friends for their prayers, moral and

financial support throughout the duration of this programme.

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ABSTRACT

SWAT was applied a large watershed (3,765km2) in south-eastern Nigeria, to predict streamflow and sediment discharge from the Ebonyi River Watershed using globally available data downloaded from the internet. Digital elevation, land-use and soil maps of the study area from global databases and historical weather data measured locally were used. SWAT model was setup to use the MapWindow GIS interface. The model predicted an average daily streamflow and sediment discharge of 24.32m3/s and 341.31 metric tonnes, respectively, at the watershed outlet for the case of no land-use change. The major land-use of the study area (savanna) was then altered to grassland and row-crop agriculture to simulate six land-use change scenarios, representing combinations of decreasing grassland (93.76% - 0.09%) and increasing agricultural land (0.09% - 93.76%). Other model inputs were kept constant and experimental runs were performed to obtain streamflow and sediment discharges for a one-year period in daily time steps. Results show that expansion of agricultural land to about 19% of the watershed area increased average daily streamflow and sediment discharge to about 29% and 44%, respectively. A further respective increase of streamflow and sediment discharge to about 52% and 79% was simulated for expansion of agricultural land to 56%. Also, about 72% and 99% increase were obtained for streamflow and sediment discharge, respectively, when agricultural land was expanded to 94% of the watershed area. Generally, as more of the watershed is allocated to row-crop agriculture, streamflow and sediment discharge increased and the measure of increase reflected watershed characteristics and conditions.

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TABLE OF CONTENTS

APPROVAL - - - - - - - - - i DEDICATION - - - - - - - - ii ACKNOWLEDGMENT - - - - - - - iii ABSTRACT - - - - - - - - - iv TABLE OF CONTENTS - - - - - - - v LIST OF TABLES - - - - - - - - vi LIST OF FIGURES - - - - - - - - vii CHAPTER ONE: INTRODUCTION 1.1 Background - - - - - - - - 1 1.2 Objectives of the Study - - - - - - 2 1.3 Justification of the Study - - - - - - 3 1.4 Scope of the Study - - - - - - - 3 CHAPTER TWO: LITERATURE REVIEW 2.1 Land-Use/Cover Change - - - - - - 4 2.2 Water Yield - - - - - - - - 5 2.3 Sediment Yield - - - - - - - 12 2.4 Water Quality - - - - - - - - 15 2.5 Watershed Modelling - - - - - - - 20 2.6 The Soil and Water Assessment Tool (SWAT) - - - 22 2.7 SWAT2005 Model Description - - - - - 25 2.8 Theory of the SWAT Model - - - - - - 26 2.9 Geographic Information System (GIS) Interface - - - 44 2.10 Performance of SWAT on Hydrologic Studies - - - 46 2.11 Performance of SWAT on Sediment Studies - - - - 48 2.12 SWAT Model: Advantages and Disadvantages - - - 49 CHAPTER THREE: METHODOLOGY 3.1 The Study Area - - - - - - - 51 3.2 Model Inputs - - - - - - - - 52 3.3 MapWindow-SWAT(MWSWAT) Model Setup - - - 56 3.4 Calculation Methods - - - - - - - 58 3.5 Land-use Scenarios - - - - - - - 58 CHAPTER FOUR: RESULTS AND DISCUSSION 4.1 Simulated Streamflow and Sediment Discharge - - - 60 4.2 Land-Use Scenarios - - - - - - - 62 4.3 Discussion - - - - - - - - 65 CHAPTER FIVE: CONCLUSION AND RECOMMENDATION 5.1 Conclusion - - - - - - - - 68 5.2 Recommendation - - - - - - - 69 REFERENCES - - - - - - - - 70 APPENDICES - - - - - - - - 81

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LIST OF TABLES

Table Page

2.1 Potential Evapotranspiration Methods and Their Required Inputs - 32

2.2 P-Factor Values and Slope Length Limits for Contouring - - 41

2.3 P-Factor Values, Maximum Strip Width and Slope Length Limits

for Continuous Strip-Cropping - - - - - 42

2.4 P-Factor Values for Contour-Farmed Terraced Field - - - 42

3.1 Distribution of Land-Use Types Ebonyi River Watershed - - 54

3.2 Distribution of Soil Types in Ebonyi River Catchment - - 55

3.3 Distribution of Land-Use Types For Scenario 0 - - - 57

3.4 Land-Use Scenarios - - - - - - - 59

3.5 Areal Coverage of Land-Use Types for Different Scenarios - 59

4.1 Average Weekly Streamflow and Sediment Discharge for Control Simulation

- - - - - - - - - 61

4.2 Average Weekly Streamflow for Land-Use Scenarios 1 to 6 - 62 4.3 Average Weekly Sediment Discharge for Land-Use Scenarios 1 to 6- 63

4.4 Average Daily Streamflow and Sediment Discharge for all Scenarios- 65

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LIST OF FIGURES

Figure Page

2.1 Schematic of SWAT Development History - - - 23

2.2 Definition Sketch Illustrating Time of Concentration - 31

2.3 Behaviour of Water Table As Assumed in the Kinematic

Storage Model - - - - - - - 36

3.1 Location of Ebonyi River Watershed in Nigeria - - 52

3.2 DEM Data for Ebonyi River Watershed - - - 53

3.3 Delineated Ebonyi River Watershed - - - - 53

3.4 Digital Land-Use Map of Ebonyi River Watershed - - 54

3.5 Digital Soil Map of Ebonyi River Watershed - - - 55

4.1 Simulated Average Weekly Streamflow for Scenario 0 - 60

4.2 Simulated Average Weekly Sediment Discharge for Scenario 0 60

4.3 Average Weekly Streamflow for Land-Use Scenarios 1 to 6 64

4.4 Average Weekly Sediment Discharge for Land-Use

Scenarios 1 to 662 - - - - - - 64

4.5 Average Daily Streamflow for Scenarios 0 to 6 - - 65

4.6 Average Daily Sediment Discharge for Scenarios 0 to 6 - 66

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CHAPTER ONE

INTRODUCTION

1.1 Background

Land-use change, which occur continuously in response to population growth

and changes in primary production activities (Cao et al., 2009) has transformed a vast

part of the natural landscape of the developing world for the last 50 years (Solaimani

et al., 2009a). Natural watershed systems maintain a balance between precipitation,

runoff, infiltration or evapotranspiration, completing the natural hydrologic cycle

(Arnold et al., 2009). Land cover and land-use changes alter the hydrological cycle of

a catchment by modifying rainfall, evaporation, and runoff (Cao et al., 2009). Today,

land-use changes as a result of human activities (deforestation, commercial

agriculture, animal husbandry and urbanisation) have altered these hydrologic

processes particularly in small catchments (Cao et al., 2009). Deforestation activities

accounts for the largest percentage of land-use change occurring on the planet today

(Calder, 2000), resulting to increases in annual streamflow and stormflow volumes in

temperate, humid and dry tropical areas (Wilk, 2002). The severity of these problems

is more pronounced in arid or semi-arid regions, where high rainfall intensities of

short duration on grazing lands and rain-fed farms, and human mismanagement of

land have accelerated soil losses by erosion (Omani et al., 2007). Soil compaction by

deforestation, pasture installation and cattle trampling increase bulk density and

penetration resistance and reduces macroporosity, infiltration rates and hydraulic

conductivities (Germer et al., 2010). Domestic and industrial waste discharge,

agricultural wastes and pollution from other non-point sources reduces water quality

(Demirci et al., 2006).

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Physically based distributed hydrological models, whose parameters have a

physical representation of the spatial variability of hydrological processes and are

capable of simulating the impact of human activities on the hydrologic cycle, are

increasingly being used to simulate complex water resource systems including the

simulation of the impacts of land-use on water resources in river basins during past

decades (Xu et al., 2009). The SWAT2005 model interfaced with MapWindow GIS is

a good example of such development. The model was developed initially by Dr. Jeff

Arnold for the USDA Agricultural Research Service (ARS) in the early 1990s in

Texas A & M University, Texas and is now being applied across the world (Neitsch et

al., 2005). The SWAT model key strength lies in its ability to predict the relative

impacts of changes in land-use on water quantity and quality (Govender and Everson,

2005), providing a scientific basis for water resources planning and management, as

well as measures to control water and soil erosion (Xu et al., 2009).

1.2 Objectives of the Study

This study is aimed at achieving the following objectives:

i. To obtain relevant historical climatic data such as rainfall, relative humidity,

sunshine duration, minimum & maximum air temperature and wind speed

from meteorological stations or the met agency (NIMET) for Nsukka.

ii. To obtain spatial data sets of digital elevation map (DEM), land cover and soil

data of Ebonyi River Basin; and

iii. To simulate the effects of land-use change on runoff and sediment yield, and

analyze simulated effects to draw useful inferences.

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1.3 Justification of the Study.

The justification for this study is informed by the following considerations:

• The need to make an efficient and cost effective evaluation of impact of land-

use change on unguaged watersheds.

• The need to apply physical based distributed hydrological models in studying

streamflow and sediment discharge.

• The need for providing a scientific basis for water resources planning and

management, and also measures to control soil erosion.

1.4 Scope of the Study

The SWAT model was used for predicting the effects of land-use change on

runoff and sediment discharge using historical weather data and spatial data sets of

digital elevation map, soil and land-use for Ebonyi River watershed.

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CHAPTER TWO

LITERATURE REVIEW

2.1 Land-Use/Cover change

Land cover refers to the physical and biological cover over the surface of land,

including water, vegetation, bare soil and or artificial structures while land-use refers

to human activities such as agriculture, forestry and building construction that alter

land surface processes (Erle, 2007). Land cover conversions constitute the

replacement of one cover type by another and are measured by a shift from one land-

cover category to another, as in the case of agricultural expansion, deforestation, or

change in urban extent (Lambin and Geist, 2006). Therefore, Land-use/cover change

is the modification/alteration of the Earth’s terrestrial surface by man in his quest to

obtain food and other essential services. Land-use change involves both the manner in

which biophysical attributes of land are manipulated and the purpose for which the

land is used (Lambin and Geist, 2006). Land can be used for forestry, parks, livestock

herding, and farmlands. The current population pressure, inadequate cultivation

practices, forest removal and high grazing intensities on rangelands and wetlands, and

marginal agricultural lands result to unwanted sediment and streamflow changes that

mainly impact the downstream natural communities (Olago and Odada, 2007).

There are many factors which trigger land-use change pattern such as

population growth, urbanization, production method and industrialization (Solaimani

et al., 2009b). Others include commercial exploitation of forest trees, demand for

firewood, forest fires, building of access roads, conventional farming, development of

settlement and urbanisation (Carpenter and Lawedrau, 2002). Demirci et al. (2006)

also pointed out the important factors that deteriorate a water body to include rapid,

unplanned urban and industrial expansions, domestic and industrial waste discharge,

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agricultural pollution, leakages from garbage dumps and other non-point sources such

as run-off from streets and highways. Alterations in vegetative cover decreases time

of concentration of flow, increase the intensity of peak flows for a given precipitation

event, and increase the frequency and intensity of extreme flow events, especially

channel-forming flows (Hubbart, 2009). These alterations tends to deteriorate water

quality by transporting sediment and other pollutants from the landscape and

increasing erosive forces within the stream channel (Hubbart, 2009).

Presently, physical expansion of urban areas and extensive use of land for

agricultural purposes are the main causes of land-use change in the developing

countries (Solaimani et al., 2009a).

2.2 Water Yield

The relationship between timber harvest and water yield has long been of

interest with worldwide studies showing that water yield usually increases

immediately after forest harvest (Hubbart et al., 2007). Experimental studies have

generally been in agreement that a removal of forest cover is associated with

increased annual streamflow in both temperate and tropical environments (Wilk and

Hughes, 2002). It is believed that forest use more water than grassland hence, reduce

annual streamflow (Zhang et al., 2008). For example, clear-cutting forest in the

United States may result in up to 540mm increase in annual water yield, and it may

take up to 30 years to return to pre-harvesting water yield conditions with natural

forest regeneration (Stednick, 1996). However, this increase depends on forest types

(coniferous, deciduous, or scrub), rainfall amounts and intensities, topography,

climate regimes, soil type and depth, and vegetation (Sun et al., 2006; Lorup and

Hansen, 1997), and tends to decrease as forest regenerate (Bari et al., 1996). The

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higher evapotranspiration losses from a forest than from any other alternative land-use

cover are the main reason for this situation (Lorup and Hansen, 1997). Forest removal

has a negative effect on evapotranspiration, thus resulting to increased streamflow.

Also, the area of cleared vegetation has an effect on water yield but in the case of

partial cuts or canopy thinning, vegetation removal may result in smaller water yield

increases than predicted by area alone because of the increased use of available

moisture by retained vegetation and vegetation in surrounding uncut areas (Hubbart et

al., 2007). Brooks et al. (2003) generalized that water yield usually increases when:

i) Forest is clear-cut or thinned.

ii) Vegetation on a watershed is converted from deep-rooted species

to shallow-rooted species.

iii) Vegetative cover is changed from plant species with high

interception capacities to species with lower interception

capacities.

iv) Species with high annual transpiration losses are replaced with

species with low annual transpiration losses.

Also, Hubbart et al. (2007) after studying results from previous studies on vegetation

management and water yield concluded that:

a. A reduction in forest cover increases water yield.

b. Afforestation reduces water yield.

Lorup and Hansen (1997) compared one year stream flow from three

catchments with similar physiographic and climatic characteristics and noted that the

annual runoff from the evergreen montane forest catchment was 30% and 36% lower

than from the other two cultivated catchments and largest difference in runoff found

during the dry season. They attributed the higher water yields from the cultivated

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catchments to a considerable higher evapotranspiration from the forested catchments,

in particular during the dry season where the evergreen and deeper rooted forest cover

has a higher water demand and a better ability to extract soil moisture to a larger

depth. After studying ninety-five (95) catchments in the United States, Stednick

(1996) found that increased water yield was detectable after 20% - 30% of a

watershed has been harvested. Generally, higher water yield responses would be

expected in regions with deep soils and high annual precipitation, whereas responses

would be lower in magnitude in dry climates (Brooks et al., 2003). Hubbart et al.

(2007) designed treatments (50% clear-cut and 50% partial cut) on a watershed in the

continental/maritime hydro-climatic region of the US and noted that water yield

increased in excess of 270mm/yr and evapotranspiration reduced by 35% for the

clear-cut area while water yield increased by more than 140mm/yr and

evapotranspiration reducing by 14% for the partial cut area. In another study and

following 21-33% patch harvest units in four sub-watersheds with areas ranging from

3.6ha – 14.2ha, annual water yield was significantly increased by a range of 13% -

29%, or an average of 358mm/yr (King, 1994). In a study to asses the potential water

yield reduction due to afforestation across China (Sun et al., 2006) observed that the

average water yield reduction vary from about 50mm/yr (50%) in the semi-arid Loess

Plateau region in northern China to about 300mm/yr (30%) in the tropical southern

region. They also concluded that afforestation in China may have a higher potential to

greatly reduce annual water yield in headwater watersheds, especially in the semi-arid

Loess Plateau region.

The hydrological effects of land-use change in the humid tropics have been a

cause of controversy and debate for many years as Brooks et al. (2003) reports that

relatively little is known about forest management-water yield relationships in this

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region. This they attributed to the availability of few controlled watershed

experiments in the tropical ecosystem which is surprising as people believe that the

humid tropical forests have a strong influence on precipitation. However, such studies

are rarely documented, but nevertheless are often stated as general facts (Lorup and

Hensen, 1997).

The few controlled documented experiments in the humid tropics show that

water yield responses to changes in vegetation cover are similar to those in the

temperate climates but would normally be of shorter duration because of rapid

regrowth of vegetation (Brooks et al., 2003). After studying runoff for one year under

different land-use/vegetation types in the Opa Reservoir Basin, South-western

Nigeria, Adediji (2006) recorded a total runoff of 5.62mm on a cleared basin, 5.24mm

on a field crop basin and a total runoff of 1.09mm in a thick bush part of the basin.

The author concluded that the mean total runoff from the cleared part of the basin was

higher than the mean total runoff recorded in the cultivated field crops, cocoa

farmlands and forested part of the basin. Also, in a study to examine the effect of

changes in land-use and vegetation cover on water yield from the Ruhudji catchment

in southern Njombe highlands of Tanzania, Atwitye (1999) reported that 88% of

variation in water discharge in the catchment is due to increased settlement,

cultivation areas and an increase in deforestation.

Contradictory results on the impacts of vegetation removal on water yield still

exist. The widespread belief that trees and tree planting will increase streamflow

during and at the end of the dry season are in conflict with the present and most other

catchment studies dealing with the effect of deforestation and afforestation on dry

season flow (Lorup and Hansen, 1997). Results from a study in northeast Thailand

found no significant changes in water balance after a decline in forest cover from 80%

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to 27% (Wilk and Andersson, 2001). Lui and Fu (1996), after comparing watershed

hydrology of an old-growth fir forest watershed with a clear-cut watershed from 1965

– 1967 found that the annual water yield from the 331ha forested watershed was

709mm/yr and that from the 291ha clear-cut watershed was only 276mm/yr. Wei et

al. (2003) also reported similar positive correlations between forests and water yield

for large basins (>100km2) for northern China which they corroborated with Russian

literature that suggests that streamflow is generally higher for large forested basins.

One unsubstantiated hypothesis was that forest increased ‘fog drip’ precipitation and

forests have lower evapotranspiration, thus increasing streamflow (Sun et al., 2006).

Wei et al. (2003) attributed these inconsistent findings to the following reasons and

include:

i. Heterogeneous large basins have large buffering capacity and may mask

the forest cover effects.

ii. Inconsistent methods and measurement error.

iii. Differences in climate and watershed characteristics among the contrasting

basins that could have obscured the forest cover effect.

Forest that occurs along coastal areas or on mountain islands (cloud forest)

sometimes produces more moisture for a watershed than they consume by

transpiration (Brooks et al., 2003). In these regions, precipitation inputs are horizontal

via fog interception by vegetation (Bruijnzeel et al., 2005). This horizontal

precipitation via fog interception is a notably important source of water for a variety

of ecosystems, from temperate evergreen forests growing in the sub-humid seasonal

climates, such as the redwoods in California (Burges and Dawson, 2004), to tropical

montane cloud forest (TMCFs) that have seasonally low rainfall (Bruijnzeel, 2001).

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Fog precipitation occurs when fog droplets are filtered by the forest canopy

and coalesce on the vegetative surfaces to form larger water droplets that drip to the

forest floor (Holder, 2005). Environments that are likely to have fog precipitation are

high elevation regions where cool temperature results in the condensation of water

vapour (LaBastille and Pool, 1978) and coastal regions on the western side of

continents where cool air from the oceans condenses and moves inland (Cereceda and

Schemenauer, 1991). Because fog occurs under conditions of high relative humidity

and low solar radiation, water intercepted from fog is less likely to be evaporated,

yielding additional precipitation through subsequent dripping of intercepted fog to the

forest floor (Gonzalez, 2000). The net precipitation in this areas are significantly

enhanced by direct canopy interception of cloud water, and when combined with low

water use by the vegetation due to reduced solar radiation and vapour deficit, canopy

wetting, and general suppression of evapotranspiration, results in net additions to the

water yield of the watershed (Hamilton, 1995).

Fog interception is influenced by several meteorological variables, including

fog liquid water content (LWC), fog drop size, wind speed and direction, and duration

and frequency of fog events (Bruijnzeel and Proctor, 1995). It is also influenced by

biotic variables related to structural characteristics of the forest, such as height, size,

spatial pattern, orientation relative to prevailing wind direction, biomass and physical

characteristics of leaves and epiphytes (Bruijnzeel et al., 2005). Several different

approaches have been used to estimate fog interception (Bruijnzeel et al., 2005)

including:

i) Water and mass balance techniques such as wet canopy water budget approach

that estimates fog interception through a comparison of wet and gross

precipitation for periods with and without fogs.

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ii) Mass balance and isotopic techniques that trace the origin of the water that

reaches the forest floor.

iii) Micrometeorological methods based on the eddy covariance techniques, under

which exchanges of cloud water between the forest and the atmosphere are

estimated as the covariance between the turbulent components of vertical wind

speed and liquid water content.

iv) Using gauges designed to intercept fog, referred to as ‘fog gauges’.

By far, the most common approach for estimating fog interception is the use of

the fog gauges (Villegas et al., 2008). Holder (2003) examined fog precipitation at

two sites having different elevations in the Sierra de las Minas Biosphere Reserve,

Guatemala. His study found that fog precipitation at the 2100m site totalled 23.4mm

from 30 July, 1995 to 7 June, 1996 and 203.4mm at the 2550m site during the same

time interval. In another study, Holwerda et al. (2006) studied the deposition of fog to

a wind-exposed 3m tall Puerto Rican cloud forest at 1010m elevation using the water

budget and eddy covariance methods. Their results showed that best estimates of

annual fog deposition amounted to 770mm/year for the summit cloud forest just

below the ridge top (according to the water budget method) and 785mm/year for the

cloud forest on the lower windward slope (using the eddy-covariance method). They

however attributed the discrepancies in their results to be related to effect of footprint

mismatch and methodological problems with rainfall measurement under the

prevailing wind conditions.

Changes in water yield that accompany land-use practices can be estimated by

the following methods (Brooks et al., 2003):

i) Regional relationships: This method involves the use of mathematical

expressions which are often the results of localized experiments or regression

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relationships. This method is only used in the region or area for which they

were developed or in other regions that have similar climates, soils,

topography, and vegetative types of the area for which they were developed.

ii) Water budget approach: This method can be used to estimate water yield for

watersheds with deep soils and high infiltration capacities. Water yield

changes associated with changes in the types of vegetative cover can be

estimated by water budget analyses using different effective rooting depths.

iii) Computer simulation models: Computer models for hydrologic simulation

include simplified empirical relationships at one extreme and detailed process-

oriented model at the other extreme. This method can contain derivations or

elements of the previously discussed methods. Also, it can consider nutrients

and complex relationships and perform sensitivity analysis where data or

assumptions are weak.

2.3 Sediment Yield

In recent times, due to various developmental activities within the river basins,

the rate of soil erosion, its transport and deposition downstream have considerably

been altered (Chandramohan and Balchand, 2007). Sediment yield is the total

sediment outflow from a watershed or drainage basin measured for a specific period

and at a defined point in a stream channel (Brooks et al., 2003). Ali and Boer (2008)

defined it as “the total sediment outflow from a basin, with suspended sediment as the

dominant component”. Soil loss occurs when the earth surface is exposed to impact of

rain drops or wind. This action detaches soil particles and makes it easy for runoff to

transport it downstream. Knowledge on sediment yields from a catchment is needed

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to estimate the quantity of sediment delivered to a downstream reservoir and then to

further determine the amount of pollutant into such reservoir (Xu et al., 2009).

Generally, a decrease in vegetative cover leads to an increase in runoff

generation and sediment detachment (Boix-Fayos et al., 2008). Also, a change in

landscape structure has an important consequence for sediment yield (ibid). For

example, the topographic modifications from road construction to skid-trail use are a

common cause for gullying in logged areas, which results in the transport of soils

from a watershed (Brooks et al., 2003).

The rate of sediment generation and transport depends on several factors

related to watershed topographic, geomorphologic and land-use/cover characteristics

(Seegar et al., 2004). Streams discharging large quantities of sediment annually are

those that drain areas undergoing active geologic erosion or improper land use

(Brooks et al., 2003). Erosion is one of the most significant forms of land degradation

(loss of soil fertility and slope instability) and is greatly influenced by land-use and

management (Solaimani et al., 2009a).

Sediment can be carried downstream as bed load (particles that move along

the river bed by rolling, skipping or sliding) or as suspended load (supported by fluid

flow and maintained by fluid turbulence) (Franeke et al., 2008). However, bed load is

flow dependent and generally accounts for around 10% of the total solid transport of a

river (ibid). They further pointed out that sediment yields are often based on the data

concerning suspended load as it is the major transporting mechanism in streams

worldwide and are composed of particles finer than 0.062mm in diameter.

Soil loss from a drainage basin is influenced by the following factors (Brooks

et al., 2003)

i) Road construction and deforestation on steep slopes.

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ii) Undercutting a slope and improper drainage.

iii) The permanent conversion of forest to pasture or crop land reduces

evapotranspiration and increases soil moisture.

Investigations of land-use change on soil erosion process using geographical

information system (GIS) (Solaimani et al., 2009b) revealed that the total erosion of

the basin decreased to 89.24% after appropriate land-use practices was implemented

on the watershed. The results showed that after appropriate land management

practices on the watershed, the sediment yield decreased from 144465.1m3/km2/yr to

15542.9 m3/km2/yr. In another study, Alansi et al. (2009) reported a marked increase

in sediment load amount from 300,000 tonnes in the 1980s to 400,000 tonnes in the

1990s. They attributed this increase to the replacement of old oil palms with new

ones, replacement of most of the rubber trees with oil palms and deforestation and

urbanisation which resulted to open bare lands, aiding runoff and sediment load

transports. Xu et al. (2009) assessed sediment yields from two basins (Chao River

Basin and Bai River Basin) into the Miyun Reservoir due to land-use changes in the

basins. Their results showed that in 1986, sediment yield from the Chao River Basin

and Bai River Basin was 246,000tonnes and 254,000tonnes respectively. In 1991, the

sediment yield was 281,000tonnes and 208,000tonnes for the Chao River Basin and

Bai River Basin respectively. They however attributed the increase in sediment yield

from the Chao River Basin to high annual precipitation (average of 587mm) which

resulted to an increase in runoff and more intensive farmlands located near the river in

the Chao River Basin. Adediji (2006) examined effects of land-use/vegetation types

and slope on soil loss within a catchment. His results showed that soil loss on slope

was highest in the built-up basins (with mean specific yield of 30.07t/km2/yr). This

was distantly followed by field crops, cocoa dominated and forested basins with mean

Page 23: USE OF THE SWAT MODEL TO EVALUATE THE IMPACT OF LAND …

specific sediment yield of 18.04t/km2/yr, 16.88t/km2/yr and 14.20t/km2/yr

respectively. His results also showed that soil loss from the valley slopes of the

studied basin correlated well with runoff and slope angle. He therefore concluded that

runoff was the most important predictor of soil loss in south-western Nigeria.

2.4 Water Quality

Water pollution occurs because human activities such as agriculture, forest

harvest, and urbanisation have altered the structure of rural landscape and increased

the quantity of substances like sediment, nitrogen, chlorine, etc., loaded to the river

system (Anbumozhi et al., 2005). Forest cover helps maintain clean water supplies by

filtering freshwater and reducing soil erosion and sedimentation (Fuentes-Junco et al.,

2004). However, deforestation undermines this process by degrading the quality of

water supplies (Mulligan, 1998). Demirci et al. (2006) studied the relationship

between land-use changes and water quality and noted that the most important factors

that affect water quality in the studied area were rapid, unplanned urban and industrial

expansions, domestic and industrial waste discharge, agricultural pollution, leakages

from closed garbage dump area and runoffs from streets and highways.

The quality of water can be completely defined and estimated by studying its

physical, chemical and biological characteristics (Garg, 2005). Water quality standard

refers to the physical, chemical or biological characteristics of water in relation to a

specified use (Brooks et al., 2003). Biological contamination of water result from

human wastes, animal wastes, industrial wastes, and chemical contaminants result

from industrial process, agricultural use of fertilizers and pesticides while physical

contaminants results from erosion and disposal of solid wastes (Schwab et al., 1993).

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Suspended sediment concentrations, levels of thermal pollutions and dissolved

oxygen are the most important physical characteristics of surface water (Brooks et al.,

2003). Throughout the world, an increase in the sediment load of streams is the most

widespread cause of degradation in the quality of water in forests (ibid), which most

times occur due to soil erosion (Schwab et al., 1993). Suspended sediments restrict

sunlight from reaching photosynthetic plants and increases turbidity. The potential

sources of suspended sediment in mountainous forested watersheds are streambed,

stream bank, forest floor (Mizugaki et al., 2008) and forest roads (Madej, 2001).

Higher concentrations of suspended sediments are often the result of accelerated

erosion caused by disturbances (road constructions, logging, heavy grazing, bush

fires, etc) in drainage areas (Brooks et al., 2003). Agricultural nutrients (Nitrogen and

Phosphorus), heavy metals and pesticides (altrazine) are known to adsorb to eroded

sediments and are transported to streams, resulting to eutrophication (Schwab et al.,

1993).

Ploughing (Edeso et al., 1999), construction of forest roads and skid trails

causes major disturbances in forested watersheds, resulting in increases in suspended

sediments (Grayson et al., 1993) and organic materials (Kreutzweiser and Capell,

2001). The dense coverage of forest canopy prevents sunlight from reaching the forest

floor and does not permit understory vegetation. In this case, sediment detachment by

raindrop impact is considered the most dominant process for sediment transport

(Miura et al., 2002), which increases with the kinetic energy of the rain drops

increases (Nanko et al., 2008). The overland flow on a forest road may emanate from

the upslope forest floor (Wemple et al., 2001) and transport the sediment produced

from the road surface and forest floor to the stream channel (Mizugaki et al., 2008).

Suspended sediment also increases during intensive grazing on steep, unstable terrains

Page 25: USE OF THE SWAT MODEL TO EVALUATE THE IMPACT OF LAND …

and fragile soils or when livestock are allowed to overgraze riparian plant community

resulting to stream-bank erosion and sediment deposition into stream channel (Brooks

et al., 2003).

Forest harvesting may also increase suspended sediment yields even when

unaccompanied by soil surface disturbances created by harvesting treatments (Hotta et

al., 2007). Results from a study (Mizugaki et al., 2008) showed that the considerable

higher contribution (69%) of the forest floor to the suspended sediment in the

watershed without a truck trail network suggests the direct transport of the sediment

from the forest floors to the stream channel by interrill erosion while the lower

contribution (46%) of the forest floor in the watershed with the truck trail networks

suggest contribution from subsurface materials of the truck trail and stream bank.

Basnyat et al., (1999) is of the opinion that land cover changes near streams have a

greater effect on stream water physico-chemical characteristics than similar land

cover changes elsewhere in the watershed. Water temperature increases due to land-

use practices results to increased biological activities and places greater demand on

the dissolved oxygen in a stream (Brooks et al., 2003). Stream temperature increases

due to urbanisation have been recognised as the significant factor in habitat loss for

both coldwater fish species (Nelson and Palmer, 2007) and invertebrates (Wang and

Kanchl, 2003). Urbanisation influences stream temperature through changes in stream

shading, channel geometry, groundwater input and inflows of storm water and waste

water (Herb et al., 2008). Clearing of riparian vegetation adjacent to a stream channel

increases the stream exposure to solar radiation, and subsequently a rise in water

temperature (Brooks et al., 2003). Brooks et al. also noted that studies in north-eastern

and north-western United States reported that annual maximum stream temperature

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rise as much as 4ºC and 15ºC when riparian vegetation was removed from small

streams.

A study (Herb et al., 2008) on the analysis of stream temperature changes due

to surface runoff from a paved surface gave the result that rainfall producing high heat

export rates lead to the greatest instantaneous change in stream temperature and was

attributed to the following causes:

i) Event-based surface temperature is strongly related to dew-point temperature

during the rainfall, air temperature and solar radiation prior to the rainfall.

ii) Rainfall events with high heat export (thermal impacts) occur from May

through September.

iii) Rainfall events with the highest heat export rates occurs mostly in the

afternoon, have runoff temperature significantly above 20ºC and have

relatively low total precipitation (average of 12mm).

iv) Rainfall events that gave the highest event-average change in stream

temperature tend to be of short duration (2hrs).

Conversely, Brown and Hannah (2007) found that 75% of summer precipitation

events led to temperature decrease in an alpine stream system and attributed it to

lower ambient air and ground surface temperature. Generally, the relationship

between stream temperature and ambient atmospheric temperature is an important

factor in determining the magnitude and direction of stream temperature changes due

to surface runoff (Herb et al., 2008).

The dissolved oxygen concentration of a water body is determined by the

solubility of oxygen, and is inversely related to temperature, pressure and biological

activities in the water body (Brooks et al., 2003) and is estimated from:

32 000077774.00079910.041022.0652.14 TTTOs −+−= …………….2.1

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where:

Os = solubility of oxygen (mg/l)

T = temperature of water (ºC)

If sufficient oxygen is present in a water body, the useful aerobic bacteria

production will flourish, which causes the biological decomposition of waste and

organic matter thus reducing the carbonaceous material from the water (Garg, 2005).

Dissolved oxygen varies in response to biological activity, with higher levels being

associated with the presence of aquatic plants (Schneider et al., 2000). Oxygen

depletion in water bodies as a result of excessive amounts of nutrients causes

eutrophication and limits aquatic plant growth (Tafangenyasha and Dzinomwa, 2005).

Increased nutrient loads in water bodies depletes dissolved oxygen by stimulating

algal blooms and decreases habitability for aquatic organisms (Brooks et al., 2005).

Demirci et al. (2006) related land-use changes in a basin to water quality in a lake and

found that the chemical oxygen demand (COD) in the lake shows a large value spread

(between 4.4mg/l and 732mg/l) and that the average coliform value was 1600 per

100ml. They attributed these results to the runoffs from impervious surfaces and

many industrial facilities discharging their wastes into the streams feeding the lake.

The chemical composition of a water body is determined largely from the

watershed system it drains (Tafangenyasha and Dzinomwa, 2005). Water is an

effective solvent, and as it comes in contact with any part of the watershed system,

chemical reactions occurs (Brooks et al., 2003). This action determines the chemical

constituents of a water body. During streamflow, there are large cumulative

increments in the chemical parameters that reduce the high quality of stream water

from forested uplands (Swank and Bolstad, 1994). The major sources of dissolved

chemical constituents in a water system that drains upland watersheds are geologic

weathering of parent rock, biological inputs and meteorological events (Brooks et al.,

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2003). Precipitations, dusts and aerosols add organic compounds and mineral ions to

the stream system. Water quality is also threatened by the application of waste water

and fertilizers from agricultural lands (Anbumozhi et al., 2005). Commercial

agriculture supports the application of large amounts of fertilizer to maximize yields

which result to the introduction of excess Nitrogen to downstream ecosystems.

Demirci et al. (2005) after assessing the relationship between land-use change and

water quality in a lake watershed concluded that the Phosphate and Nitrate levels in

the lake are as a result of sewage discharge and agricultural application of fertilizers.

Tafangenyasha and Dzinomwa, (2005) attributed the pollution of the Runde River in

Zimbabwe to agricultural runoff, domestic and industrial effluents. They concluded

that it led to the increase in the nutrient (Nitrogen, Nitrates and Phosphorus) levels,

resulting to eutrophication and distribution of macro invertebrates. Results from a

study (Akintola and Gbadegesin, 1997) on the effects of land-use practices on water

quality of a reservoir indicated fairly low and tolerable levels of nitrate (< 10mg/l),

nitrate-nitrogen (< 6.0mg/l), dissolved oxygen (< 8.0mg/l) and total dissolved solids

(< 220mg/l). The significant increase in some of these parameters, especially the

nitrate-nitrogen content was attributed to the increased land area (900% - 1150%)

devoted to arable farming and increase in the amount nitrogenous fertilizer used.

2.5 Watershed Modelling

Watershed models are powerful tools for simulating the effect of watershed

processes and management on soil and water resources (Moriasi et al., 2007). Borah

and Bera (2003) defined watershed models as “useful tools for assessing the

environmental conditions of a watershed and evaluating best management practices

(BMP), implementation of which can help reduce the damaging effects of stormwater

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runoff on water bodies and the landscape”. Watershed models link sources of

pollutants to receiving water bodies as non-point source loads. Therefore, watershed

modelling is the application of watershed models to simulate the effect of watershed

processes and management activities on water quality, water quantity and soil quality.

Watershed modelling, in which physical and chemical processes of hydrology and

water quality are represented in a computer simulation, is often employed by

hydrologist and environmental scientists to evaluate potential impacts from changes

in land-use or climatic conditions (Johnson, 2009). Watershed models provides viable

alternatives to measuring water and sediment supply from an ungauged watershed and

supports environmental policy decisions (Lai, 2005).

Geographic information systems (GIS) stores and displays the data (land-use,

soil, climate and DEM) needed by watershed models to predict both water and

pollutant runoffs from a watershed. Examples of watershed-scale hydrologic and non-

point source pollution models are SWAT (Soil and Water Assessment Tool), HSPF

(Hydrologic Simulation Program Fortran), AGNPS (Agricultural Non-Point Source

Pollution), AnnAGNPS(Annualised Agricultural Non-Point Source Pollution),

ANSWERS (Areal Non-Point Source Watershed Environment Response Simulation),

PRMS (Precipitation-Runoff Modelling System), KINEROS (Kinematic Runoff and

Erosion), WEPP (Water Erosion Prediction Project), DWSM (Dynamic Watershed

Simulation Model), etc. (Borah, 2002). Clear understandings of these models are

necessary in other not to misuse them and also the choice of use of any of these

models depends on the problem, watershed size, desired spatial and temporal scales,

expected accuracy, user skills and computer resources (Borah and Bera, 2003).

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2.5.1 Importance of Watershed Modelling

The importance of modelling a watershed includes:

i) It enables researchers to study long-term impacts of land management

practices in large complex watersheds (George and Leon, 2008).

ii) Results obtained from watershed modelling provides scientific basis for water

resources planning and management, as well as measures to control water and

soil losses from the study area (Xu et al., 2009).

iii) Studying the impacts of changes in land management practices and vegetation

on water quality and quantity is less tedious (Govender and Everson, 2005).

2.6 The Soil and Water Assessment Tool (SWAT)

The development of the Soil and Water Assessment Tool (SWAT) model is a

continuation of the United States Department of Agriculture (USDA), Agricultural

Research Service modelling experience that spans a period of roughly 30 years

(Gassman et al., 2007). It emerged mainly from the Simulator for Water Resources in

Rural Basins (SWRRB) model, and contains features from Agricultural Research

Service (ARS) models: Chemicals, Runoff, and Erosion from Agricultural

Management Systems (CREAMS), Groundwater Loading Effects on Agricultural

Management Systems (GLEAMS), Erosion Productivity Impact Calculator which is

known today as Environmental Impact Policy Climate (EPIC), Routing Outputs to

Outlets (ROTO) and QUAL2E model (Borah and Bera, 2003) as shown in Figure 2.1.

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Fig. 2.1: Schematic of SWAT Development History (Gassman et al., 2007)

SWAT was developed to assist water resources managers in analyzing the impacts of

land management practices on water, sediment, and agricultural chemical yields in

large complex watersheds (Setegn et al., 2008).

Development of SWRRB began in the early 1980s with the modification of

the daily rainfall hydrology model from CREAMS (Neitsch et al., 2005). Surface

runoff and other computations were expanded to ten sub-basins. Other modifications

include an improved peak runoff rate method, calculation of transmission losses,

groundwater return flow, reservoir storage, EPIC crop growth sub-model, weather

generator, sediment transport component, GLEAMS pesticide fate component,

optional USDA-SCS technology for estimating peak runoff rates and newly

developed sediment yield equations (Gassman et al., 2007). The limitation of

simulating streamflow for basins extending to over several thousand square

kilometres led to the development of the ROTO (Routing Outputs to Outlet) model

(Arnold et al., 1995) which links multiple SWRRB runs together (Neitsch et al.,

2005). This led to the merging of ROTO and SWRRB into a single model – SWAT

CREAMS

EPIC

GLEAMS Pesticide component

Daily rainfall hydrology component

Crop growth component

SWRRB (multiple subbasin, other components)

QUAL2E

In-stream kinetics

SWAT

Routing structure

ROTO

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(Fig. 2.1) with SWAT retaining all the features of SWRRB. Also, the in-stream

kinetics component from the QUAL2E model was incorporated into SWAT (Fig. 2.1).

Since the development of the SWAT model in the early 1990s, it has

undergone continued review and expansion of its capabilities (Arnold and Fohrer,

2005). The most significant improvements of the model between releases include

(Neitsch et al., 2005):

• SWAT94.2: Multiple hydrologic response units (HRUs) incorporated.

• SWAT96.2: Auto-fertilization and auto-irrigation added as management

options; canopy storage of water incorporated; a CO2 component added to

crop growth model for climatic change studies; Penman-Monteith potential

evapotranspiration equation added; lateral flow of water in the soil based on

kinematic storage model incorporated; in-stream nutrient water quality

equations from QUALZ2E added; in-stream pesticide routing.

• SWAT98.1: Snow melt routines improved; in-stream water quality improved;

nutrient cycling routines expanded; grazing, manure applications, and tile flow

drainage added as management options; model modified for use in Southern

Hemisphere.

• SWAT99.2: Nutrient cycling routines improved, rice/wetland routines

improved, reservoir/pond/wetland nutrient removal by settling added; bank

storage of water in reach added; routing of metals through reach added; all

year references in model changed from last 2 digits of year to 4-digit year;

urban build up/wash off equations from SWMM added along with regression

equations from USGS.

• SWAT2000: Bacteria transport routines added; Green & Ampt infiltration

added; weather generator improved; allow daily solar radiation, relative

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humidity, and wind speed to be read in or generated; allow potential ET values

for watershed to be read in or calculated; all potential ET methods reviewed;

elevation band processes improved; enabled simulation of unlimited number

of reservoirs; Muskingum routing method added; modified dormancy

calculations for proper simulation in tropical areas.

• SWAT2005: Bacteria transport routines improved; weather forecast scenarios

added; sub-daily precipitation generator added; the retention parameter used in

daily CN calculation may be a function of soil water content or plant

evapotranspiration.

Today, the model has gained international acceptance as a robust

interdisciplinary watershed modelling tool, as evidenced by international SWAT

conferences, hundreds of SWAT-related papers presented at numerous other scientific

meetings, and dozens of articles published in peer-reviewed journals (Gassman et al.,

2007). Applications of the SWAT model include studies by Setegn et al. (2008),

Govender and Everson (2005), Xu et al. (2009), and Kaur et al. (2003).

2.7 SWAT2005 Model Description

SWAT is an acronym for Soil and Water Assessment Tool, a river basin, or

watershed scale model developed by Dr. Jeff Arnold for the USDA Agricultural

Research Service (Neitsch et al., 2005). It is a physically based, distributed,

hydrological model that can operate on daily, monthly or annual time-steps, and can

be used to predict the impacts of land management practices on water, sediment and

agricultural chemicals in catchments (Cao et al., 2009).

The main driving force behind SWAT modelling is the hydrological cycle

which is divided into the land phase (controls the amount of water and sediment in

Page 34: USE OF THE SWAT MODEL TO EVALUATE THE IMPACT OF LAND …

receiving waters) and the water routing phase (simulates movement of water and

sediment through the channel networks). The SWAT model delineates watersheds

into sub-basins interconnected by stream network and each sub-basin is further

divided into hydrologic response units (HRUs) based upon unique soil or land-use

characteristics (Somura et al., 2007). Flow and sediment loadings from each HRU in a

sub-basin are summed up and routed through channels to the watershed outlets

(Arnold et al., 2001).

The SWAT2005 model has the following characteristics (Neitsch et al., 2005):

a. It is physically based; requires specific information about weather, soil

properties, topography, vegetation and land management practices to directly

model physical processes such as water movement, sediment movement, etc.

b. It uses readily available inputs.

c. It is computationally efficient; it can simulate very large basins.

d. It enables users to study long-term impacts.

SWAT2005 has eight major components – hydrology, weather, sedimentation,

soil temperature, crop growth, nutrients, pesticides, and agricultural management

(Borah and Bera, 2003).

2.8 Theory of the SWAT Model

2.8.1 Overview

The SWAT model allows a number of different physical processes to be

simulated in a watershed (Neitsch et al., 2005). It has eight major components –

hydrology, weather, sedimentation/erosion, soil temperature, crop growth, nutrient,

pesticides, and agricultural management (Arnold and Fohrer, 2005). In SWAT, a

watershed is subdivided into sub-basins that are spatially related to one another, and,

Page 35: USE OF THE SWAT MODEL TO EVALUATE THE IMPACT OF LAND …

further, into hydrological response units (HRUs), which are homogenous units that

posses unique land-use/land-cover and soil attributes and account for the complexity

of the landscapes within the sub-basins (Githui et al., 2009). Alternatively, a

watershed can be subdivided into only sub-watersheds that are characterized by

dominant land-use, soil type, and management (Gassman et al., 2007).

Water balance is the driving force behind everything that happens in a

watershed (Neitsch et al., 2005). The daily water budget in each HRU is computed

based on daily precipitation, runoff, evapotranspiration, percolation, and return flow

from the subsurface and groundwater flow (Borah and Bera, 2003). The hydrologic

cycle simulated by SWAT is based on the water balance equation (Setegn et al., 2008)

as shown in equation 3.

( )∑=

−−−−+=t

igwseepasurfday QWEQRSWSWt

1o ………………………..2.2

where:

SWt = final soil water content (mm water)

SWº = initial soil water content in day i (mm water)

t = time (days)

Rday = amount of precipitation in day i (mm water)

Qsurf = amount of surface runoff in day i (mm water)

Ea = amount of evapotranspiration in day i (mm water)

Wseep = amount of water entering the vadose zone from the soil profile in day i

(mm water)

Qgw = amount of return flow in day i(mm water)

Once the loadings (water and sediment) to the main channel are determined, they are

routed through the stream network of the watershed to obtain the total runoff and

sediment yield (Githui et al., 2009).

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2.8.2 Hydrology

2.8.2.1 Surface Runoff

Surface runoff is the portion of the precipitation that makes its way towards

rivers, oceans, etc as surface flow (Garg, 2005). Runoff occurs only when the rate of

precipitation exceeds the rate at which water may infiltrate into the soil (Schwab et

al., 1993). As rain falls, a part of it is intercepted by vegetation and some is stored in

depressions on the ground surface, which later infiltrates into the soil or evaporates.

The amount of precipitation that will be absorbed by the soil will depend on the

prevailing soil moisture content at the time of precipitation. If the rain continues

further, water starts infiltrating into the soil, and when the rate of precipitation

exceeds the rate of infiltration, water starts ponding on the soil surface and results to

surface flows.

Surface runoff volume is computed using a modification of the SCS Curve

Number (CN) method or the Green and Ampt infiltration method. The USDA SCS

curve number equation is given as (USDA SCS, 1972):

( )( )SIR

IRQ

aday

adaysurf +−

−=

2

……………………………………………………2.3

where:

Qsurf = accumulated runoff/rainfall excess (mm)

Rday = rainfall depth for the day (mm)

Ia = initial abstractions which includes surface storage, interception and infiltration

prior

to runoff (mm)

S = retention parameter

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and

−= 1010004.25

CNS …………………………………………………….2.4

where:

Ia = 0.2S

Therefore,

( )( )SR

SRQ

day

daysurf 8.0

2.0 2

−= ……………………………………………………2.5

The Green and Ampt equation was developed to predict infiltration assuming

excess water at the surface at all times (Green and Ampt, 1911). Their equation

assumes that the soil profile is homogeneous and antecedent moisture is uniformly

distributed in the profile. Mein and Larson (1973) developed a methodology for

determining ponding time with infiltration using the Green and Ampt equation as:

∆⋅+⋅=

t

vwfet F

Kfinf,

,inf 1θϕ

……………………………………………..2.6

where:

tf ,inf = infiltration rate at time t (mm/hr)

Ke = effective hydraulic conductivity (mm/hr)

wfϕ = wetting front matric potential (mm)

vθ∆ = change in volumetric moisture content across the wetting front (mm/mm)

tFinf, = cumulative infiltration rate at time t (mm)

Nearing et al. (1996) developed an equation to calculate the effective

hydraulic conductivity as a function of saturated hydraulic conductivity and curve

number. The equation is given as:

( ) 2062.0exp051.01

82.56 286.0

−×+

×=

CNKK sat

e ………………………………………2.7

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where:

Ks= effective hydraulic conductivity (mm/hr)

Ksat= saturated hydraulic conductivity (mm/hr)

CN = curve number

Wetting front matric potential is calculated as a function of porosity, percent

sand and percent clay (Rawls and Brakensiek, 1985).

8.2...

00799.0

003479.00000136.0

001602.0006108.

049837.0000344.0

809479.3001583.032561.75309.6

exp10

2

22

222

2

2

××

−××−××

−××+××

+××−××+

×+×+×−

=

soils

soilccs

soilcsoils

soilscssoil

csoil

wf

M

MMM

MM

MMM

M

φ

φ

φφ

φφ

φ

ϕ

where:

soilφ = porosity of the soil (mm/mm)

Mc = percent clay content

Ms = percent sand content

( )soilv FCSW φθ +×

−=∆ 95.01 ……………………………………...…..2.9

where:

vθ∆ = change in volumetric moisture content across the wetting front (mm/mm)

SW = soil water content of the entire profile excluding the amount of water held in the

profile at wilting point (mm).

FC = amount of water in the soil profile at field capacity (mm)

soilφ = porosity of the soil (mm/mm)

PEAK RUNOFF RATE: The peak runoff rate is the maximum runoff flow rate that

occurs with a given rainfall event and indicates the erosive power of a storm (Neitsch

et al., 2005). The modified rational formula used to estimate peak flow rate is given as

(ibid):

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conc

surftcpeak t

AreaQq

6.3××

……………………………………………..2.10

where:

qpeak = peak runoff rate (m3/s)

tcα = fraction of daily rainfall that occurs during the time of concentration

Qsurf = surface runoff (mm)

Area = subbasin area (km2)

tconc = time of concentration for the subbasin (hr)

3.6 = unit conversion factor

In the beginning of a rainfall event, only a certain amount of runoff will reach

the watershed outlet, but after some time, the runoff from the entire watershed area

will reach the outlet. At this time, the runoff rate equals the rainfall rate and the time

required to reach this equilibrium condition is known as the time of concentration

(Garg, 2005). Michael and Ojha (2003) defined the time of concentration of a

watershed “as the time required for runoff water to flow from the most remote point

(in time of flow) of the watershed area to the outlet” (A to B,) as shown in Fig. 2.2.

Fig 2.2: Definition Sketch Illustrating Time of Concentration (Michael and Ojha, 2003)

Kirpich (1940) developed a method for computing time of concentration. It is given

as:

385.077.00195.0 −= gc SLT ………………………………………….……….2.11

where:

Tc = time of concentration (min)

B

A

B

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L = maximum length of flow (m)

Sg = watershed gradient (m/m)

2.8.2.2 Evapotranspiration

Evapotranspiration includes evaporation from the plant canopy, transpiration

through the tissues of living plants, sublimation and evaporation from the soil

(Neitsch et al., 2005). Penman (1956) defined potential evapotranspiration (PET) as

“the amount of water transpired by a short green crop, completely shading the ground,

of uniform height and never short of water”. Numerous empirical methods have been

developed to estimate potential evapotranspiration and are based primarily on the

assumptions that the energy available for evaporation is proportional to temperature

(Schwab et a., 1993). Examples are the Penman-Monteith method (Monteith, 1965),

Priestly-Taylor method (Priestly and Taylor, 1972) and Hargreaves method

(Hargreaves et al., 1985). These three methods vary in the amount of required inputs

as shown in Table 2.1.

Table 2.1: Potential Evapotranspiration Methods and Their Required Inputs (Neitsch et al., 2005). S/N PET Methods Input(s) 1 Penman-Monteith Solar radiation, air temperature, relative humidity and

wind speed 2 Priestly-Taylor Solar radiation, air temperature, and relative humidity. 3 Hargreaves Air temperature

PENMAN-MONTEITH METHOD: The Penman-Monteith equation combines

components that account for energy needed to sustain evaporation, the strength of the

mechanism required to remove the water vapour and aerodynamic and surface

resistance terms (Neitsch et al., 2005). The Penman-Monteith equation is given as

(Monteith, 1965):

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( ) [ ]

.1

++∆

−+−∆

=

a

e

a

zzpairnet

rr

reeCGH

λ

o

l

……………………………………..2.12

where:

Eλ = latent heat flux density (MJ/m2/day)

E = depth rate evaporation (mm/day)

∆ = slope of the saturation vapour pressure temperature curve (kPa/ºC)

Hnet = net radiation (MJ/m2/day)

G = heat flux density to the ground (MJ/m2/day)

airl = air density (kg/m3)

Cp = specific heat at constant pressure (MJ/kg/ºC) o

ze = saturation vapour pressure of air at height z (kPa)

ze = water vapour pressure of air at height z (kPa)

γ = psychrometric constant (kPa/ºC)

re =plant canopy resistance (s/m)

ra = diffusion resistance of the air layer (s/m)

PRIESTLEY-TAYLOR METHOD: Priestley and Taylor (1972) developed a

simplified version of the combination equation for use under humid conditions. The

equation is given as:

( )GHE netpet −⋅+∆∆

⋅=γ

αλ o ……………………………………………2.13

where:

λ = latent heat of vaporisation (MJ/kg)

oE = potential evapotranspiration (mm/day)

petα = coefficient

∆ = slope of the saturation vapour pressure-temperature curve (kPa/ºC)

γ = psychrometric constant (kPa/ºC)

netH = net radiation (MJ/m2/day)

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G = heat flux density to the ground (MJ/m2/day)

HARGREAVES METHOD: The Hargreaves equation which was originally derived

from eight years of cool-season Alta fescue grass lysimeter data from Davis,

California is given as (Hargreaves et al., 1985):

( ) ( )8.170023.0 5.0minmax +−⋅= avTTTHE ooλ ………………………………2.14

where:

λ = latent heat of vaporisation (MJ/kg)

oE = potential evapotranspiration (mm/day)

oH = extraterrestrial radiation (MJ/m2/day)

maxT = maximum air temperature for a given day (ºC)

minT = minimum air temperature for a given day (ºC)

avT = mean air temperature for a given day (ºC)

2.8.2.3 Soil Water

Soil water is essentially the soil moisture held in the pore spaces of the soil

mass and lying near enough to the surface and within the crop root zone (Michael and

Ojha, 2003). Water returns back to the earth surface through precipitation. One part of

this precipitation percolates into the ground, forming ground water reservoir; another

infiltrated part and before joining the watertable, joins the river channels (Garg,

2005).

PERCOLATION: This is the downward flow of water in saturated or nearly

saturated soil at hydraulic gradient of the order of 1.0 or less (Micheal and Ojha,

2003). Water is allowed to percolate if the water content exceeds the field capacity

water content for that layer and the layer below is not saturated (Neitsch et al., 2005).

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They gave the equation for the calculation of the amount of water which percolates to

the next layer as:

∆−−=

percexcesslylyperc TT

tSWw exp1,, …………………………………….2.15

where:

lypercw , = amount of water percolating to the underlying soil layer on a given day

(mm)

excesslySW , = drainable volume of water in the soil layer on a given day (mm)

t∆ = length of the time step (hrs)

percTT = travel time for percolation (hrs)

LATERAL FLOW: During rainfall, rainwater percolates vertically until it

encounters an impermeable layer, and ponds above it forming a saturated zone of

water. This saturated zone is the source of water for lateral subsurface flow (Neitsch

et al., 2005). The SWAT model incorporates a kinematic wave storage model for

subsurface flow developed by Sloan et al. (1983) and summarised by Sloan and

Moore (1984). This kinematic storage model simulates flow in a two-dimensional

cross-section along a flow path down a steep hill slope (Fig. 2.3). The kinematic

wave approximation of lateral flow assumes that the lines of flow in the saturated

zone are parallel to the impermeable boundary and the hydraulic gradient equals the

slope of the bed.

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Fig. 2.3: Behaviour of the Water Table as Assumed in the Kinematic Storage Model (Neitsch et al., 2005).

where:

Dperm = depth of permeable soil surface layer (mm)

Lhill= length of hillslope segment (mm)

αhill= angle of hillslope segment to the horizontal (º)

From Fig. 2.3, the drainable volume of water stored in the saturated zone of

the hillslope segment per unit area is calculated from the equation given by Neitsch et

al. (2005):

2

.1000,

hilldoexcessly

LHSW ⋅⋅=

φ …………………………………………..2.16

where:

excesslySW , = drainable volume of water stored in the saturated zone of the hillslope per

unit area (mm)

oH = saturated thickness normal to the hillslope length at the outlet expressed as a

fraction of the total thickness (mm/mm)

dφ = drainable porosity of the soil (mm/mm)

hillL = hillslope length (m)

1000 = factor needed to convert meters to millimetres

The drainable porosity of the soil layer is calculated from the equation:

fcsoild φφφ −= ………………………………………………………….2.17

Lhill

Dperm

Impermeable layer

αhill Ho Steady state water table Transient water table

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where:

dφ = drainable porosity of the soil layer (mm/mm)

soilφ = total porosity of the soil layer (mm/mm)

fcφ = porosity of the soil layer filed with water when the layer is at field capacity

water content (mm/mm)

The net discharge at the hillslope outlet, Qlat is given as:

latlat VHQ o24= ……………………………………………...………….2.18

where:

latQ = water discharge from the hillslope outlet (mm/day)

oH = saturated thickness normal to the hillslope at the outlet expressed as a fraction

of the total thickness (mm/mm)

latV = velocity of flow at the outlet (mm/hr)

Equation for the velocity of flow at the outlet is given as:

( )hillsatlat SinKV α⋅= ………………………………………………….2.19

where:

= saturated hydraulic conductivity (mm/hr)

= slope of the hillslope segment

But

slpKV satlat ⋅= ………………………………………………………..2.20

slp = increase in elevation per unit distance

Therefore,

⋅⋅=

hilld

satexcesslylat L

slpKSWQ

φ,2

024.0 ……………………….…………2.21

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BASE FLOW/GROUNDWATER FLOW: This is the water that percolates to the

ground watertable, and later after long times, joins the river system (Garg, 2005). An

aquifer is a geologic unit that can store enough water and transmit it at a rate fast

enough to be hydrological significant (Dingman, 1994). An unconfined aquifer is an

aquifer whose steady upper boundary is the water table and contributes return flow to

streams within the watershed while a confined aquifer is an aquifer bounded above

and below by geologic formations whose hydrologic conductivity is significantly

lower that that of the aquifer and contributes return flow to streams outside the

watershed (Arnold et al., 1993).

The steady-state response of groundwater flow to recharge is given as

(Hooghoudt, 1940):

wthlgw

satgw h

LKQ ⋅

⋅=

8000 …………………………………………………2.22

where;

gwQ = groundwater flow or base flow into the main channel on day I (mm)

satK = hydraulic conductivity of the aquifer (mm/day)

gwL = distance from the subbasin divide for the groundwater system to the main

channel (m)

wthlh = water table height (m)

2.8.3 Erosion

Water erosion is the detachment, transport, and deposition of soil particles by

the erosive forces of raindrops and surface flow of water (Schwab et al., 1993).

During rainfall, raindrop impact on unprotected soil surface detaches soil particles,

initiating transport of these particles by the action of flowing water to the rills. These

particles moves from smaller rills to larger rills, then into ephemeral channels, and

finally into continuously flowing rivers (Neitsch et al., 2005). Non-point erosion

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refers to soil erosion from the land surface rather than from channels and gullies

(Schwab et al., 1993). Geologic erosion occurs without human influence while

accelerated erosion occurs when human activities increases erosion rate (Neitsch et

al., 2005). There is a direct relationship between total runoff and soil loss from

agricultural lands (Michael and Ojha, 2005)

Erosion caused by rainfall and runoff is computed with the Modified

Universal Soil Loss Equation (MUSLE) (Williams, 1995). MUSLE is a modified

version of the Universal Soil Loss Equation (USLE) developed by Wischmeier and

Smith (1978).

Modified Universal Soil Loss Equation (MUSLE): The Modified Universal Soil

Loss Equation is given as (Williams, 1995) is given as:

( ) CFRGLSPCKareaqQSed USLEUSLEUSLEUSLEhrupeaksurf ⋅⋅⋅⋅⋅⋅⋅= 56.08.11 ….2.23

where:

Sed = sediment yield on a given day (meric tons)

surfQ = surface runoff volume (mm/ha)

peakq = peak runoff rate (m3/s)

hruarea = area of the HRU (ha)

USLEK = USLE soil erodibility factor (0.013 metric ton m2hr/ (m3-metric ton cm)

USLEC = USLE cover and management factor

USLEP = USLE support practice factor

USLELS = USLE topographic factor

CFRG = coarse fragment factor

Soil erodibility factor is the soil loss rate per erosion index unit for a specified

soil as measured on a unit plot (Wischmeier and Smith, 1978) and is given as:

hisandorgcsiclcsandUSLE ffffK ⋅⋅⋅= − …………………………………………2.24

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where:

csandf = a factor that gives low soil erodibility for soils with high coarse sand contents

and high values for soils with little sand.

siclf − = a factor that gives low soil erodibility factors for soils with high clay to silt

ratios.

orgcf = a factor that reduces soil erodibility for soil with high organic carbon content.

.hisandf = a factor that reduces soil erodibility for soils with extremely high sand

contents.

These factors are calculated from;

( )

28.2.......................................

10019.2251.5exp

1001

10017.0

1

27.2..........................................................95.272.3exp

25.01

26.2.........................................................................................

25.2.............................................100

10256.0exp3.02.0

3.0

−⋅+−+

−⋅−=

⋅−+

⋅−=

+

=

−⋅⋅−⋅+=

ss

s

hisand

orgc

siltc

siltsicl

siltscsand

MM

M

f

orgCorgCorgCf

MMMf

MMf

where:

Ms = percent sand content (0.05 – 2.00mm diameter particles)

Msilt = percent silt content (0.002 – 0.05 diameter particles)

Mc = percent clay content (< 0.002mm diameter particles)

OrgC = percent organic carbon content of the layer (%)

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The USLE cover and management factor, CUSLE, is defined as the “ratio of soil

loss from land cropped under specified conditions to the corresponding loss from

clean tilled, continuous fallow (Wischmeier and Smith, 1978) and is given as:

( ) ( )[ ] [ ]

[ ]

+

⋅−⋅−=

mnUSLE

surfmnUSLEUSLE CLn

rsdCLnLnC

,

, 00115.0exp8.0exp ………….2,29

where:

CUSLE= minimum value for the cover and management factor for the land cover

rsdsurf = amount of residue on the soil surface (kg/ha)

The minimum factor C can be estimated from a known average annual C

factor using the equation below (Arnold and William, 1995):

[ ] 1034.0463.1 ,, += aaUSLEmnUSLE CLnC ……………………………….…2.30

where:

mnUSLEC , = minimum C factor for the land cover

aaUSLEC , = average annual C factor for the land cover

The support practice factor, PUSLE, is defined as the “ratio of soil loss with a

specific support practice to the corresponding loss with up-and-down slope culture

(Neitsch et al., 2005). Values for PUSLE, for contour tillage, strip cropping on the

contour and terrace systems are given in Tables 2.2, 2.3 and 2.4 respectively.

Table 2.2: P Factor Values and Slope Length Limits for Contouring (Wischmeier and Smith, 1978) Land slope (%) PUSLE Maximum length (m) 1 – 2 0.60 122 3 – 5 0.50 91 6 – 8 0.50 61 9 – 12 0.60 37 13 – 16 0.70 24 17 – 20 0.80 18 21 – 23 0.90 15

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Table 2.3: P Factor Values, Max Strip Width and Slope Length Limits for Continuous Strip-cropping (Wischmeier and Smith, 1978) Land Slope (%)

PUSLE values Strip Width (m) Max. Length (m)

A B C 1 – 2 0.30 0.45 0.60 40 244 3 – 5 0.25 0.38 0.50 30 183 6 – 8 0.25 0.38 0.50 30 122 9 – 12 0.30 0.45 0.60 24 73 13 – 16 0.35 0.52 0.70 24 49 17 – 20 0.40 0.60 0.80 18 37 21 – 23 0.45 0.68 0.90 15 30 AFor 4-year rotation of row crop, small grain with meadow seeding, and 2 yrs of meadow. A second row crop can replace the small grain if meadow is established in it. BFor 4-yr rotation of 2 yrs row crop, winter grain with meadow seeding and 1-yr meadow. CFor alternate strips of row crop and winter grain

Table 2.4: P Factor Values for Contour-Farmed Terraced Fields (Wischmeier and Smith, 1978) Land slope (%)

Farm Planning Computing Sediment Yield2 Contour P Factor1

Stripcrop P Factor

Graded Channels Sod Outlet

Steep Backslope Underground Outlet

1 – 2 0.60 0.30 0.12 0.05 3 – 8 0.50 0.25 0.10 0.05 9 – 12 0.60 0.30 0.12 0.05 13 – 16 0.70 0.35 0.14 0.05 17 – 20 0.80 0.40 0.16 0.06 21 – 23 0.90 0.45 0.18 0.06 1Use these values for control on interterrace erosion within specified soil loss tolerances. 2These values include entrapment efficiency and are used for control of offsite sediment within limits and for estimating the field’s contribution to watershed sediment yield.

The topographic factor, LSUSLE, is the expected ratio of soil loss per unit area

from a field slope to that from a 22.1m length of uniform 9% slope under otherwise

identical conditions and is given as (Neitsch et al., 2005):

( )( )065.056.441.651.22

2 ++⋅

= hillhill

mhill

USLE SinSinLLS αα ……………..2.31

where;

hillL = slope length

m = exponential term

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hillα = angle of the slope

The exponential term, m, is calculated from:

[ ]( )slpm ⋅−−= 835.35exp16.0 ………………………………………2.32

The relationship between hillα and slp is given as;

hillslp αtan= …………………………………………………………2.33

The coarse fragment factor is caudated from:

( )rockCFRG ⋅−= 053.0exp …………………………………………2.34

where:

Rock = % rock in the first soil layer (%)

UNIVERSAL SOIL LOSS EQUATION (USLE): The universal soil loss equation

(Williams, 1995) is:

CFRGLSPCKEISed USLEUSLEUSLEUSLEUSLE ⋅⋅⋅⋅⋅⋅= 292.1 …………..2.35

where:

Sed = sediment yield on a given day (metric tons/ha)

USLEEI = rainfall erosion index (0.017m-metric ton cm/m2hr)

USLEK = USLE soil erodibility factor (0.013 metric ton m3 hr/ (m3-metric ton cm)

USLEC = USLE cover and management factor

USLEP = USLE support practice factor

USLELS = USLE topographic factor

CFRG = coarse fragment factor

2.8.3.1 Sediment in Lateral and Base Flow

The amount of sediment contributed by lateral and groundwater flow is

calculated from (Neitsch et al., 2005):

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( )

1000sedhrugwlat

lat

ConcareaQQSed

⋅⋅+= ………………………………..2.36

where:

latSed = sediment loading in lateral and groundwater flow (metric tons)

latQ = lateral flow for a given day (mm)

gwQ = groundwater flow for a given day (mm)

hruarea = area of the HRU (km2)

sedConc = concentration of sediment in lateral and groundwater flow (mg/L)

2.9 Geographic Information System (GIS) Interface

A second trend that has paralleled the historical development of the SWAT

model is the creation of various Geographic Information System (GIS) interface tools

to support the input of topographic, land-use, soil and other digital data into SWAT

(Gassman et al., 2007). GIS interfaces have been developed for SWAT using both

GRASS (Graphical Resources Analysis Support System) and ArcView (Arnold and

Fohrer, 2005). The GRASS input interface automatically subdivides a basin (grids or

sub-watersheds) and then extracts model input data from map layers and associated

relational databases for each sub-basin (Arnold and Fohrer, 2005). Input data are

collected and written to appropriate data files. By selecting a sub-basin from a GIS

map, maps and graph outputs can be displayed.

The ArcView-SWAT (AVSWAT) interface tool was designed to generate

model inputs from ArcView 3x GIS data layers and execute SWAT within the same

framework (Gassman et al., 2007). The SWAT ArcView system consists of three key

components (Diluzio et al., 1998):

i. Pre-processor generating sub-basin topographic parameters and

model input parameters.

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ii. Editing input data and execute simulation.

iii. Postprocessor viewing graphical and tabular results.

The export of data from GIS to the SWAT model and the return of results for

display are accomplished by Avenue routines addressed directly by the interactive

tools of GIS (e.g. setting up parameter values via customized menus) and the

exchange of data is fully automatic (Arnold and Fohrer, 2005). The most recent

version of the interface is denoted AVSWAT-X, which provides additional input

generation functionality, including soil data input from both the USDA-NRCS State

Soils Geographic (STATSGO) and Soil Survey Geographic (SSURGO) databases for

applications of SWAT2005 (Gasman et al., 2007).

There is a substantial price tag on these current commercial GIS systems that

is currently used by SWAT (George and Leon, 2008). The Waterbase Project, a

project of the United Nations University with aim to advance the practice of

Integrated Water Resources Management (IWRM) in developing countries developed

a suitable, open source GIS (MapWindow) system that would support the generation

of SWAT input data (ibid). MWSWAT is an interface between SWAT and the open

source GIS MapWindow, and is specifically designed to use freely available GIS data

for anywhere in the world, as well local data when available (George and Leon,

2009).

A variety of other tools have been developed to support executions of SWAT

simulations, including (Gassman et al., 2007):

i) The interactive SWAT (i_SWAT) software which supports SWAT simulations

using a Window interface with an Access database.

ii) The Conservation Reserve Program (CRP) Decision Support System (CRP-

DSS).

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iii) The AUTORUN system, which facilitates repeated SWAT simulations with

variations in selected parameters.

iv) A generic interface (iSWAT) program, which automates parameter selection

and aggregation for iterative SWAT calibration simulations.

2.10 Performance of SWAT on Hydrologic Studies

Hydrologic components of the SWAT model such as surface runoff,

evapotranspiration, recharge and stream flow have been validated at smaller scales

with the EPIC, GLEAMS and SWRRB models. Interactions between surface flow and

subsurface flow in SWAT are based on a linked surface-subsurface flow model

developed by Arnold et al. (1993). Current reach and reservoir routing techniques are

based on the ROTO approach, which was developed to estimate flow and sediment

yields in large basins using sub area inputs from the SWRRB model (Arnold, 1995).

Configuration of routing schemes in SWAT is based on the approach given by Arnold

et al. (1994).

Surface runoff, evapotranspiration and streamflow components of SWAT have

been refined and validated at larger scales including a U.S. national assessment of

streamflow and evapotranspiration (Arnold et al., 1998). Measured data from Illinois

watersheds were used to successfully validate surface runoff, groundwater flows, ET

in the soil profile, ground water recharge and groundwater height parameters (Arnold

and Allen, 1996). Arnold et al., (2000) compared groundwater recharge and discharge

(baseflow) results from SWAT to filtered estimates for the 491,700km2 Upper

Mississippi River Basin. SWAT’s capability to predict surface and subsurface flow

for a 33.4km2 watershed in Maryland, United State was evaluated by Chu and

Shirmohammadi (2004). Their result showed that SWAT was not able to simulate an

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extremely wet year, but with the wet year removed, the surface runoff, base flow, and

streamflow results were within acceptable accuracy on a monthly basis. The authors

then used the corrected base flow result to improve the subsurface flow result.

Rosenthal et al. (1995) using SWAT and with no calibration simulated 10

years of monthly stream flow, and observed that SWAT underestimated the extreme

events, though their results showed R2 = 0.75. Rosenthal and Hoffman (1999)

successfully used SWAT to simulate flows and sediment loadings on a 9,000 km2

watershed in central Texas to locate potential water quality monitoring sites.

Srinivasan et al., (1998) validated SWAT for streamflow and sediment loads for the

Mill Creek watershed in Texas for 1965 – 1968 and 1968 – 1975. Their results

showed monthly streamflow rates were well predicted but the SWAT model

overestimated streamflow in a few years during the spring/summer months. However,

they noted that the SWAT model predicted soil erosion and sediment transport

satisfactorily considering the model’s limitations.

As part of the HUMUS (Hydrologic Unit Model for the United States) project,

Arnold, (1999) validated annual runoff and ET rates across the entire continental

United States. Bingner (1996) simulated runoff for 10 years for a watershed in

Northern Mississippi, and observed that the SWAT model produced reasonable

results in the predicted daily and annual runoffs from multiple sub-basins, with the

exception of wooded sub-basins.

Arnold (1999) interfaced SWAT with a GIS to evaluate streamflow and

sediment yield data in the Texas Gulf Basin with drainage areas ranging from

10,000km2 to 110,000 km2 and observed that simulated sediment yield agreed

reasonably well considering inputs uncertainties, sampling errors and model

assumptions. Mapfumo et al. (2004) tested the SWAT’s ability to simulate soil-water

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patterns in small watersheds under three grazing intensities in Alberta, Canada. These

authors observed that SWAT had a tendency to over predict soil-water in dry

conditions and to under predict it in wet conditions. However, they concluded that the

model was adequate in simulating soil-water patterns for all three watersheds within a

daily time step.

2.11 Performance of SWAT on Sediment Studies

Comparisons of SWRRB–ROTO sediment output for three watersheds in

Texas compared favourably with measured data as (Arnold, 1995). Sediment loss

predictions using SWAT were further tested in nine watersheds in Texas (Arnold,

1999), New York (Benaman and Shoemaker, 2005) and India (Tripathi et al., 2004).

Though these studies varied in watershed sizes, interval and duration of measured

sediment loss, validation criteria and other factors, these authors all noted that the

SWAT sediment predictions agreed with measured values.

SWAT was interfaced with HUMUS to conduct a national research on the

effect of management scenarios of water quality and quantity (Jayakrishnan et al.,

2005). A study (Kirsch et al., 2002) using SWAT showed that implementation of

improved tillage practices can reduce sediment yields by almost 20% in Rock River in

Wisconsin. Also, SWAT has been applied in Indian watersheds: identification of

critical or priority areas for soil and water management in a watershed (Kaur et al.,

2004) and the impact of different tillage systems on sediment losses (Tripathi et al.,

2005).

This wide range of SWAT applications has underscored the model’s flexibility

and robustness in studying watershed’s runoff and sediment transport processes, even

thought some studies have shown the low performance capability of the tool in some

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areas, especially when comparing predicted streamflow and sediment yield with

measured data. Model users have addressed the tool weaknesses by modifying its

components to accurately predict specific hydrologic processes. This trend is likely to

continue in the future in other to respond to the needs of the growing user population

and also to provide prediction accuracy.

2.12 SWAT Model: Advantages and Disadvantages

Some of the key features that made the SWAT model applicable for a wide

range of studies area:

a) It can realistically represent the spatial variability of catchment characteristics

(Mishra et al., 2007).

b) It is characterized by its availability (i.e. it is an open source model) and user-

friendliness in handling input data (Xu et al., 2009).

c) It is an operational model that assists water resource managers in assessing

water supplies and non-point source pollution on large river basins (Arnold

and Fohrer, 2005).

d) Watersheds with no monitoring data (e.g. stream gauge data) can be modelled

with SWAT i.e. SWAT can be applied to a large ungauged basin (Neitsch et

al., 2005).

e) It has reduced the laborious and tedious process involved in evaluating land

management impacts on water resources as a result of human activities on the

watershed. It is capable of modelling catchment areas varying between few

hectares to thousand of sq. km.

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f) Physical based hydrological models (e.g. SWAT) assist water managers to

identify the most vulnerable erosion-prone areas of a catchment and select

appropriate management practices (Xu et al., 2009).

The SWAT model limitations are as follows;

a) Accuracy of the predicted impacts on water resources as a result of land-use

changes on a watershed depends highly on the use of local data as inputs

(George and Leon, 2009).

b) For accurate results, meteorological stations should be situated within and

around the watershed area. Due to the heterogeneity of watersheds, a number

of meteorological stations are required to represent the spatial variation in the

hydro-meteorological characteristics of the area.

c) Where local spatial data sets are lacking, the only alternative is to obtain such

online and this requires accessibility to the internet.

d) The SWAT model requires a GIS to display, analyze and represent the spatial

variations in catchment characteristics. Most GIS have high price tagged on

them and are expensive.

e) Real time land-use maps, one of the basic inputs to the SWAT can only be

extracted through remote sensing as satellite imageries and processed using

digital image processing technique. However, the acquisition of satellite

imageries is expensive and also the expertise required for the image

interpretation is another major limitation in model’s application in developing

countries.

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CHAPTER THREE

METHODOLOGY

3.1 The Study Area

The study area is the River Ebonyi watershed (3,765km2) located on the

western border of the Cross River Plains, headed by the Udi-Nsukka Escarpment

(Fig.3.1). Geographically, the River Ebonyi catchment is situated between latitudes

5º78'N and 6º50'N and longitudes 7 º47'E and 8 º00'E. It is situated in the transition

zone between the Guinea-Congolian wetter-type forest and Guinea savannah eco-

climatological zones with elevation ranging between 105m and 565m above sea level

(Campling et al., 2002). The mean annual temperature is 23ºC and the mean annual

rainfall is 1577mm with the peak rainfall period between mid-August and mid-

September (Campling et al., 2000).

Campling et al. (2002) reported that two major landforms are found within the

catchment: (1) the sandstone escarpment of the Udi-Nsukka Cuesta, which is

characterised by deeply weathered aerosols with low water-holding capacity and high

hydraulic conductivity, and (2) the shale peneplains of the Cross River Plains. Major

ravines are found near the sandstone escarpment in association with spring lines and

excessive surface runoff caused from tarmac roads (Gobin et al., 1999). The upper

part of the catchment has a rolling to undulating topography, intersected by incised

streams that flow to narrow valley bottom while the lower part has a flatter

topography, with extensive areas of waterlogging in the wet season and a wide valley

bottom (Campling et al., 2002).The basin has a rural set-up and is used extensively for

agriculture (Agbo, 1991).

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Fig 3.1: Location of Ebonyi River Watershed in Nigeria

3.2 Model Inputs

The spatially distributed data sets (GIS input) needed for the MWSWAT

interface include the digital elevation model (DEM), land-use, soil and historical local

weather data.

3.2.1 Digital Elevation Map (DEM)

Topography was defined by a DEM that describes the elevation at any point in

a given area at a specific spatial resolution. DEM was derived using the NASA 90-m

Shuttle Radar Topographic Mission (SRTM) dataset, version 4 (SRTM, 2004).

Subbasin parameters such as slope gradient, slope length of the terrain and the stream

network characteristics were derived from the DEM. The DEM (Fig. 3.2) has a

resolution of 90m and was provided in mosaic 5 deg × 5 deg tiles. The DEM was used

to delineate the watershed into 29 sub-basins using the TauDEM (Terrain Analysis

Using Digital Elevation Model) software as shown in Fig. 3.3.

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Fig. 3.2: DEM Data for Ebonyi River Watershed

As the DEM covered a larger area in which part of it was not required for the

modelling work, a mask was created for the study area so that only the masked

portion of the DEM will be used for the modelling study.

Fig. 3.3: Delineated Ebonyi River Watershed

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3.2.2 Land-Use

This is one of the most important factors that affect runoff and soil erosion in a

watershed. Digital land-use map of the study area (Fig. 3.4) was obtained from the

University of Maryland, Global Land Cover Classification (Hensen et al., 1998) at

1km spatial resolution. SWAT calculated the area covered by each land-use. The

different land-use/cover types within the study area are presented in Table 3.1.

Parameters values for the different land-use types are shown in Appendix 1.

Parameters values for residential land-use type are shown in Appendix 2.

Fig. 3.4: Digital Land-Use Map of Ebonyi River Watershed Table 3.1: Distribution of Land-Use Types in Ebonyi River Watershed. Land-use Types Area (ha) Watershed (%) Savannah (SAVA) 350234.78 93.03 Cropland/woodland mosaic (CRWO) 4745.16 1.26 Evergreen broadleaf forest (FOEB) 163.48 0.04 Dry land, cropland and pasture (CRDY) 20882.27 5.55 Residential medium density (URMD) 362.54 0.10

3.2.3 Soil Data

SWAT model requires different soil textural and physico-chemical properties

such as soil texture, available water content, hydraulic conductivity, bulk density,

sand percent, silt percent, clay percent and organic content carbon content for the

different layers of each soil type. The soil map of the study area (Fig. 3.5) was

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obtained from the Digital Soil Map of the World and Derived Soil properties CD-

ROM (FAO, 2003) at a scale of 1:5000000. Major soil types in the study area are

shown in Table 3.2 and their parameter value are presented in Appendix 3.

Fig. 3.5: Digital Soil Map of Ebonyi River Watershed

Table 3.2: Distribution of Soil Types in Ebonyi River Watershed Soil Types Area (ha) Watershed (%) Gd16-2-3a-1201 2103.22 0.56 Nd5-1a-1567 22039.34 5.85 Nd16-2-3a-1553 341376.36 90.68 Ap15-1a-1068 10782.07 2.86 Bf6-1105 87.25 0.02 3.2.4 Weather Data

SWAT requires daily meteorological data that can either be read from a

measured data set or generated by a weather generator model. The weather data used

in this study for driving the hydrological cycle are daily values of rainfall, and

maximum and minimum temperature for the period 1973 – 1982. These data were

obtained from University of Nigeria, Nsukka (UNN) Agrometeorological Service

(6º87'N, 7 º43'E, 442m) and is presented in Appendix 4. Most of the daily data were

however missing. For this study, a weather generator file which contains the statistical

data needed to generate representative daily climate data for the watershed was

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developed and used to generate missing temperature and rainfall data and also to

simulate other weather parameters such as relative humidity, solar radiation and wind

speed. However, the unavailability of breakpoint (30 min) rainfall data, which will be

needed to prepare this weather generator file, limited the use of 20 years climate

record to prepare this file as stated in the SWAT User Manual. Thus, one year of

climate record was used to create a weather generator file is presented in Appendix 5.

3.3 MapWindow-SWAT (MWSWAT) Model Setup

The Soil and Water Assessment Tool (SWAT 2005) was interfaced with

MapWindow GIS version 4.7.5. This model setup is based around three basic steps.

i) Watershed delineation

ii) Hydrologic response unit (HRU) definition

iii) SWAT setup and run

The required spatial datasets (DEM, land-use and soil) were projected to the

same projection called UTM zone 32N using MapWindow GIS, which is the

transverse mercator projection parameters for Nigeria using MWSWAT. The DEM

was used to delineate the watershed into several hydrologically connected sub-

watersheds. The watershed shapefile was created and used as a mask which was

superimposed on the DEM. The MWSWAT interface used only the masked area for

stream delineation and helped reduced the processing time of GIS functions. The

initial stream network was defined based on drainage area threshold approach. An

output was manually added where model outputs were later measured. In this study,

an initial threshold area (the minimum drainage area required to form the origin of a

stream) of 100km2 was used to create 29 sub-basins with one outlet as shown in

Figure 3.3.

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The land-use and soil map in a projected grid format were loaded into the

MWSWAT interface to determine the area of each land-soil category simulated

within each sub-watershed. These maps were then related to the SWAT land-use and

soil classes in the SWAT database. An intermediate slope band of 5% was selected

and the DEM was used for slope classification. In this study, HRUs were formed

based on a particular combination of land-use, soil and slope. A minimal percentage

of 5% was selected as the threshold level for HRU definition which resulted to 96

HRUs in the whole basin. Land-uses, soils and slope that cover a percentage of the

subbasin area less than the threshold level were eliminated and reapportioned so that

100% of the land area in the subbasin was modelled. The threshold level is a function

of the project goal and the amount of detail required. Land-use types remaining in the

study area after setting the threshold level is shown in Table 3.3. The Soil and Water

Assessment (SWAT) tool uses the Hydrological Response Units (HRUs) as the basis

for its modelling HRUs enable the model to reflect differences in ET and other

hydrologic conditions for different land-uses and soils. Runoff and sediment yield

were estimated separately for each HRU and routed to obtain total runoff and

sediment yield for the watershed.

Table 3.3: Distribution of Land-Use Type for Scenario 0. Land-use Types Area (ha) Watershed (%) Savanna (SAVA) 353800.04 93.86 Cropland/woodland mosaic (CRWO) 3124.06 0.83 Dry land, cropland and pasture (CRDY) 19540.37 5.17 Evergreen broadleaf forest (FOEB) 163.48 0.04 Residential medium density (URMD) 370.98 0.10 From Table 3.3, most portion of the watershed is covered by savanna, which accounts

for 93.86% of the watershed area. URMD and FOEB land-use types were eliminated

as they fall below the threshold level of 5% but were exempted during HRU

definition.

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Ten years of daily rainfall and minimum and maximum temperature data was

prepared in Notepad and read into the SWAT model. The weather generator

component of the SWAT model used the weather generator file to generate other

weather parameters (solar radiation, relative humidity, wind speed) and also to fill

missing climatic data.

3.4 Calculation Methods

In this study, the Soil Conservation Society (SCS) curve number method was

used to estimate surface runoff. Penman-Monteith method was used for the estimation

of potential evapotranspiration. Peak runoff rate was computed using a modification

to the Rational formular. Modified Universal Soil Loss Equation (MUSLE) was used

to compute sediment yield, the Green-Ampt equation was used to estimate infiltration

rate. Streamflow was routed using the variable storage method.

3.5 Land-use Scenarios

The ‘Split Landuse’ option of the SWAT model can be used to define more

precise land-uses than the land-use map provides and affect how HRUs are defined.

The Savanna land-use type which covers 93.86% of the watershed was split into

Grassland (GRSS) and Agriculture-Row Crop (AGRR). Land-use scenarios were

created from the split Savanna land-use type for different percentage combinations of

grassland and agriculture as shown in Table 3.4. Watershed area in percent for the

different land-use types for all scenarios is shown in Table 3.5.

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Table 3.4: Land-Use Scenarios Scenario Grassland (GRSS) Agriculture-Row Crops (AGRR) 1 99.9% 0.1% 2 80% 20% 3 60% 80% 4 40% 60% 5 20% 80% 6 0.1% 99.9%

Table 3.5: Areal Coverage of Land-Use Types for Different Scenarios Scenario SAVA CRWO CRDY FOEB URMD

0 93.86% 0.83% 5.17% 0.04% 0.10% GRSS AGRR 0.83% 5.17% 0.04% 0.10%

1 93.76% 0.09% 0.83% 5.17% 0.04% 0.10% 2 75.08% 18.77% 0.83% 5.17% 0.04% 0.10% 3 56.31% 37.54% 0.83% 5.17% 0.04% 0.10% 4 37.54% 56.31% 0.83% 5.17% 0.04% 0.10% 5 18.77% 75.08% 0.83% 5.17% 0.04% 0.10% 6 0.09% 93.76% 0.83% 5.17% 0.04% 0.10%

These scenarios were not determined from realistic location factors, and as

such are not plausible and should not be seen as future projections. Herein, the

emphasis was on expansion of agriculture (row crop). In each of the sub-basins

already delineated, new HRUs representing the scenarios were determined. Sample

outputs of the distribution of HRUs within the sub-basins for Scenarios 0,1,2,3,4,5,

and 6 are presented in Appendices 6,7,8,9,10,11, and 12. Other model inputs (DEM,

soil and weather data) were kept constant while varying land-use scenarios. Model

experimental run was performed using Scenarios 1 – 6, 164 HRUs were created for

each simulation, and streamflow and sediment discharge were predicted for one year

at a daily time step at the watershed outlet.

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CHAPTER FOUR

RESULTS AND DISCUSSION

4.1 Simulated Streamflow and Sediment Discharge

The watershed delineation and HRU definition of River Ebonyi Basin for

Scenario 0 resulted in 29 subbasins and 96 HRUs. Results for the control simulation

(Scenario 0) processed for average weekly streamflow and sediment discharge are

shown in Figures 4.1 and 4.2, respectively, and in Table 4.1.

Fig. 4.1: Simulated Average Weekly Streamflow for Scenario 0

Fig. 4.2: Simulated Average Weekly Sediment Discharge for Scenario 0

0

500

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Table 4.1: Average Weekly Streamflow and Sediment Discharge for Control Simulation Week Streamflow (m3/s) Sediment Discharge (tonnes)

1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 8 0 0 9 0 0 10 0 0 11 0 0 12 0 0 13 0 0 14 0 0 15 0.08 0.029 16 0 0 17 0.00051 0.000011 18 0 0 19 1.83 7.54 20 249.16 4359.5 21 55.11 524.24 22 23.34 148.43 23 0 0 24 26.31 294.15 25 102.86 1399.47 26 9.36 23.19 27 0 0 28 2.03 8.3 29 39.3 351.18 30 8.99 52.16 31 2.6 9.09 32 0 0 33 3.39 12.43 34 0.1 0.14 35 0.35 0.56 36 5.09 31.59 37 205.21 3527.72 38 150.77 2130.06 39 131.07 1675.64 40 0 0 41 1.95 6.29 42 146 2063.85 43 43.96 373.1 44 59.37 790.01 45 0 0 46 0 0 47 0 0 48 0 0 49 0 0 50 0 0 51 0 0 52 0 0

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4.2 Land-use Scenarios

Similarly, results for the land-use change simulations for Scenarios 1 to 6,

processed for average weekly streamflow and sediment discharge are shown in Table

4.2 and 4.3 respectively, and plotted in Figures 4.3 and 4.4.

Table 4.2: Average Weekly Streamflow for Land-Use Scenarios 1 to 6 Week Scenarios

1 2 3 4 5 6 1 0 0 0 0 0 0 2 0 0 0 0 0 0 3 0 0 0 0 0 0 4 0 0 0 0 0 0 5 0 0 0 0 0 0 6 0 0 0 0 0 0 7 0 0 0 0 0 0 8 0 0 0 0 0 0 9 0 0 0 0 0 0 10 0 0 0 0 0 0 11 0 0 0 0 0 0 12 0 0 0 0 0 0 13 0 0 0 0 0 0 14 0 0 0 0 0 0 15 0.16 0.66 1.29 1.89 2.43 2.91 16 0.00026 0.053 0.19 0.32 0.49 0.66 17 0.0086 0.068 0.19 0.28 0.38 0.46 18 0 0 0 0 0 0 19 4.31 8.28 12.1 15.81 19.29 22.45 20 283.99 312.64 337.79 358.38 374.35 386.33 21 62.99 64.98 67.7 72.23 78.93 87.25 22 26.14 24.17 24.78 27.38 31.94 38.32 23 0 0 0 0 0 0 24 34.63 46.88 56.77 64.24 69.56 72.77 25 118.38 122.62 129.02 137.55 148.07 160.37 26 7.96 6.88 5.9 4.94 4.05 3.26 27 0 0.0061 0.032 0.071 0.12 0.15 28 4.28 7.56 10.21 12.27 13.85 14.97 29 50.85 58.72 66.9 75.12 83.18 91.33 30 11.85 16.01 19.44 22.2 24.45 26.32 31 3.48 3.05 3.39 4.31 5.78 7.6 32 0 0 0 0 0 0 33 7.11 12.55 17.31 21.57 25.35 28.64 34 0.22 0.11 0.3 0.63 1.11 1.78 35 0.65 2.14 3.36 4.43 5.39 6.36 36 9.07 13.56 17.86 21.66 25.15 28.68 37 236.89 262.19 284.13 301.68 314.69 323.78 38 169.29 172.66 179.05 189.41 203.81 221.45 39 147.8 164.06 177.62 188.46 196.82 202.77 40 0 0 0 0.0045 0.024 0.047 41 4.31 9.72 14.55 18.85 22.6 25.98 42 170.81 185.04 199.63 214.26 228.89 243.31 43 55.49 64.6 72.75 81.09 89.21 96.98 44 66.8 74.49 81 85.99 89.42 91.71 45 0 0 0 0 0 0

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46 0 0 0 0 0 0 47 0 0 0 0 0 0 48 0 0 0 0 0 0 49 0 0 0 0 0 0 50 0 0 0 0 0 0 51 0 0 0 0 0 0 52 0 0 0 0 0 0 Table 4.3: Average Weekly Sediment Discharge for Land-Use Scenarios 1 to 6

Week Scenario 1 2 3 4 5 6

1 0 0 0 0 0 0 2 0 0 0 0 0 0 3 0 0 0 0 0 0 4 0 0 0 0 0 0 5 0 0 0 0 0 0 6 0 0 0 0 0 0 7 0 0 0 0 0 0 8 0 0 0 0 0 0 9 0 0 0 0 0 0 10 0 0 0 0 0 0 11 0 0 0 0 0 0 12 0 0 0 0 0 0 13 0 0 0 0 0 0 14 0 0 0 0 0 0 15 0.15 1.41 3.71 6.21 8.94 11.68 16 0.0000039 0.052 0.32 0.63 1.27 1.78 17 0.002 0.057 0.33 0.49 0.87 1.09 18 0 0 0 0 0 0 19 24.37 60.03 95.94 132.91 167.16 199.29 20 5153.04 5891.51 6539.33 7033.77 7377.13 7561.33 21 688.78 836.2 971.19 1086.05 1181.4 1264.97 22 186.14 170.87 181.09 210.98 264.62 340.97 23 0 0 0 0 0 0 24 416.81 588.83 737.24 848.58 917.33 949.56 25 1706.93 1907.05 2124.24 2304.33 2475.64 2631.09 26 19.63 13.81 8.94 8.01 8.13 6.52 27 0 0.0016 0.02 0.063 0.12 0.21 28 25.63 57.46 86.85 111.64 130.33 146.09 29 493.52 632.15 762.57 875.31 970.27 1046.15 30 86.46 141.41 189.1 229.83 258.26 275.48 31 15 12.39 14.47 20.62 31.26 45.95 32 0 0 0 0 0 0 33 35.34 78.43 118.44 155.92 191.06 228.13 34 0.36 0.17 0.56 1.61 3.75 7.54 35 1.67 9.77 17.8 26.33 34.43 41.06 36 65.26 115.48 164.16 206.59 240.64 274.92 37 4252.24 4948.89 5526.99 5968.2 6238.94 6384.14 38 2513.34 2749.45 2980.76 3205.84 3435.41 3681.26 39 2050.93 2507.24 2879.62 3135.47 3292.89 3347.35 40 0 0 0 0.00096 0.015 0.033 41 19.83 58.31 97.47 134.47 169.14 199.43 42 2567.69 2982.33 3383.17 3708.54 3970.82 4160.01 43 535.96 697.45 854.56 993.06 1111.62 1212.33 44 948.42 1154.52 1315 1436.06 1487.31 1497.32 45 0 0 0 0 0 0 46 0 0 0 0 0 0

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47 0 0 0 0 0 0 48 0 0 0 0 0 0 49 0 0 0 0 0 0 50 0 0 0 0 0 0 51 0 0 0 0 0 0 52 0 0 0 0 0 0 Fig. 4.3: Average Weekly Streamflow for Land-Use Scenarios 1 to 6 Fig. 4.4: Average Weekly Sediment Discharge for Land-Use Scenarios 1 to 6

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4.3 Discussion

In order to evaluate the impacts of the land-use change scenarios, their digital

land-use maps were imported into SWAT with the same set of DEM, soil and weather

data. These results were compared to the results from the control or no-change

simulation. Figures 4.3 and 4.4 show that all scenarios follow the same pattern with

increases in streamflow and sediment discharge as more of the watershed area is

allocated to row-crop agriculture. Average daily streamflow and sediment discharge

for all scenarios are shown in Table 4.4 and plotted in Figures 4.5 and 4.6

respectively.

Table 4.4: Average Daily Streamflow and Sediment Discharge for all Scenarios Scenario Streamflow (m3/s) Sediment Discharge (tonnes) 0 24.32 341.31 1 28.34 418.22 2 31.33 491.29 3 34.20 557.20 4 36.92 610.66 5 39.49 651.46 6 41.93 680.98

Fig. 4.5: Average Daily Streamflow for Scenarios 0 to 6

0

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Sce 0 Sce 1 Sce 2 Sce 3 Sce 4 Sce 5 Sce 6Scenario

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flow(

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Fig. 4.6: Average Daily Sediment Discharge for Scenarios 0 to 6

Comparisons between simulated average daily streamflow rates from the

control land-use scenario and that from the six land-use change scenarios show that

the average daily streamflow increased by 16.53% for scenario 1, 28.82% for scenario

2, 40.63% for scenario 3, 51.81% for scenario 4, 62.38% for scenario 5 and 72.41%

for scenario 6. Consequently, average daily sediment discharge increased by 22.53%

for scenario 1, 43.94% for scenario 2, 63.25% for scenario 3, 78.92% for scenario 4,

90.87% for scenario 5 and 99.52% for scenario 6.

Expectedly, scenario 6 yielded the most streamflow and sediment, since

streamflow and sediment discharge increases as more of the watershed area is alloted

to row-crop agriculture. These increases were observed to be higher during the wet

season and lower during the dry season of the year. Removal of vegetative cover,

especially grass, would generally increase average surface runoff. Row-crop

agriculture is also known to leave the soil bare for a longer period of time, particularly

during periods of crop planting and early growth stages. Therefore, as more of the

watershed is converted to row-crop agriculture, the rates of overland flow increase

leading to higher runoff rates. This results to increased detachment and transportation

0

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Sce 0 Sce 1 Sce 2 Sce 3 Sce 4 Sce 5 Sce 6

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of sediments. Also, ridging which characterizes row-crop agriculture creates a very

loose and porous upper soil condition which facilitates soil erosion.

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CHAPTER FIVE

CONCLUSION AND RECOMMENDATION

5.1 Conclusion

The need to provide food and shelter to the ever increasing world population

has led to alterations in our natural watershed systems, affecting the hydrologic

balance. The capability of MapWindow GIS in using freely available global, spatial

data (DEM, land-use and soil) from online sources, and interfaced with the Soil and

Water Assessment Tool has been utilized in this study to evaluate the impacts of land-

use change on streamflow and sediment discharge from the Ebonyi River watershed.

Digital elevation, land-use and soil maps of the study area from global

databases and historical weather data measured locally were inputted into the model

and a one year simulation run in daily time steps performed. Simulated average daily

streamflow and sediment discharge are 24.32m3/s and 341.31tonnes respectively for

the control simulation. The major land-use of the study area (savanna) was then

altered to grassland and row-crop agriculture to create six land-use change scenarios

representing different combinations of decreasing grassland (93.76% - 0.09%) and

increasing agricultural land (0.09% - 93.76%). Other model inputs were kept constant

and experimental runs were performed to obtain streamflow and sediment discharge

for one year in daily time steps.

Average daily simulated streamflow and sediment discharge increased by 29%

and 44% respectively as about 19% of the watershed is allocated to row-crop

agriculture. A further increase by 72% and 99% for streamflow and sediment

discharge, respectively, was obtained as the agricultural area increased to 94% of the

watershed area. Therefore, with DEM, climatic and soil inputs held constant,

conversion of watershed area from grassland to row-crop agricultural land has

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accounted for a major difference in streamflow and sediment discharge from the

Ebonyi River watershed.

5.2 Recommendation

It is recommended that further research in this area should be conducted with

fine resolution spatial data sets which will improve spatial accuracy. The coarse/poor

resolution data sets used in this study were the only ones available from global data

bases.

Conduct of similar research should be done with rainfall being spatially

represented within the study area. In this study, rainfall was not spatially represented

as only one weather station outside the study area was used. Also, unavailability of

breakpoint rainfall data limited the use of only one year of weather record to calculate

parameters in the weather generator file instead of twenty years, as recommended for

the SWAT model.

Use of measured data to validate the SWAT model is highly recommended

and would be a major contribution to watershed management in Nigeria.

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REFERENCES Adediji, A. (2006). Land Use, Runoff, and Slopewash in the Opa Reservoir Basin,

Southwestern Nigeria. Journal of Environmental Hydrology 14 (3). Agbo, J.U. (1991). The Hydrogeology of the Ebonyi River Basin, South-eastern

Nigeria. Unpublished Doctoral Dissertation, Department of Geology, University of Nigeria, Nsukka.

Akintola, F.O. and Gbadegesin, A. (1997). Land-Use Changes and Water Quality in Impounded Water-Supply Dams in Southeast Nigeria. Freshwater Contamination (Proceedings of Rabut Symposium 54). IAHS Publ. no. 243. Alansi, A.W., Amin, M.S.M., Waleed, A.R.M., Aimrun, W and Ezrin, M.H. (2009). The Effect of Development and Land-Use Change on Rainfall-Runoff and

Runoff-Sediment Relationship Under Humid Tropical Condition: Case Study of Bernam Watershed, Malaysia. Journal of Scientific Research 31 (1): 88 – 105.

Ali, K.F. and Boer, D.H. (2008). Factors Controlling Specific Sediment Yield in the

Upper Indus River Basin, Northern Pakistan. Hydrol. Process. 22: 3102 – 3114.

Anbumozhi, V., Radhakrishnan, J. and Yamaji, E. (2005). Impact of Riparian Buffer

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APPENDICES

Land-Use Scenarios and SWAT Model Input Data for Experimental Runs

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APPENDIX 1 Land Cover Parameter Values for Different Land-Use Types

PARAMETERS SAVA GRSS AGRR CRWO CRDY FOEB Biomass-energy ratio (MJ/m2) 34 34 39 24.25 34.25 15 Harvest index for optimal growing condition 0.89999 0.89999 0.5 0.61 0.68 0.75999 Maximum potential leaf area index 2 2.5 3 4 3.5 5 Fraction of the plant growing season 0.05 0.05 0.15 0.1 0.1 0.15 Fraction of maximum leaf area index corresponding to the 1st point on the optimal leaf development curve

0.1 0.1 0.05 0.05 0.05 0.69999

Fraction of the plant growing season 0.25 0.25 0.5 0.449999 0.5 0.25 Fraction of maximum leaf area index corresponding to the 2nd point on the optimal leaf development curve

0.69999 0.69999 0.95 0.94999 0.94999 0.99

Fraction of growing season when leaf area begins to decline 0.34999 0.34999 0.7 0.81999 0.81999 0.99 Maximum canopy height (m) 1 1 2.5 3.5 0.75 10 Maximum root depth (m) 2 2 2 2.75 2 3.5 Optimal temperature for plant growth (ºC) 25 25 25 30 27.5 30 Minimum temperature for plant growth (ºC) 12 12 8 10.5 11.5 0 Normal fraction of Nitrogen in yield (kg N/kg yield) 0.016 0.016 0.014 0.0107 0.0217 0.0015 Normal fraction of Phosphorus in yield (kg P/kg yield) 0.00219 0.00219 0.0016 0.00179 0.00329 0.003 Normal fraction of Nitrogen in plant biomass at emergence (kg N/kg biomass) 0.01999 0.01999 0.047 0.025 0.052 0.006 Normal fraction of Nitrogen in plant biomass at 50% maturity (kg N/kg biomass)

0.012 0.012 0.0177 0.0092 0.01979 0.002

Normal fraction of Nitrogen in plant biomass at maturity (kg N/kg biomass) 0.00499 0.00499 0.0138 0.00719 0.0131 0.0015 Normal fraction of Phosphorus in plant biomass at emergence (kg P/kg biomass)

0.00139 0.00139 0.0048 0.0034 0.00719 0.00069

Normal fraction of Phosphorus in plant biomass at 50% maturity (kg P/kg biomass)

0.001 0.001 0.0018 0.0013 0.0027 0.00039

Normal fraction of Phosphorus in plant biomass at maturity (kg P/kg biomass) 0.00069 0.00069 0.0014 0.00109 0.0019 0.0003 Lower limit of harvest index 0.89999 0.89999 0.3 0.12999 0.57499 0.6

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Minimum value of USLE C factor for water erosion applicable to the land cover/plant

0.003 0.003 0.2 0.101 0.10199 0.001

Maximum stomatal conductance at high solar radiation and low vapour pressure deficit (m.s-I)

0.00499 0.00499 0.007 0.004 0.00499 0.002

Vapour pressure deficit corresponding to the 2nd point on the stomatal conductance curve

4 4 4 4 4 4

Fraction of max. stomatal conductance corresponding to the 2nd point on the stomatal conductance curve

0.75 0.75 0.75 0.75 0.75 0.75

Rate of decline in radiation use efficiency per unit increase in vapour pressure deficit

10 10 7.2 8.25 9.25 8

Elevated CO2 atmospheric concentration (µL CO2/L air) 660 660 660 660 660 660 Biomass energy ratio 39 39 45 26 36 16 Plant residue decomposition coefficient 0.05 0.05 0.05 0.05 0.05 0.05 Mannings “n” value for overland flow 0.15 0.15 0.14 0.11999 0.15 0.1 SCS runoff curve number for soil Hydrologic Group A 44 49 67 51.5 58 25 SCS runoff curve number for soil Hydrologic Group B 65 69 78 68.5 73 55 SCS runoff curve number for soil Hydrologic Group C 76.5 79 85 78 81 70 SCS runoff curve number for soil Hydrologic Group D 82 84 89 83 85.5 77 Minimum leaf area index for plant during dormant period (m2/ m2) 0.75 Fraction of tree biomass accumulated each year that is converted to residue during dormancy

0 0 0 0 0 0.3

SAVA: Savanna GRSS: Grassland AGRR; Agricultural land – row crops CRWO: Cropland/woodland mosaic CRDY: Cropland, dryland and pasture FOEB: Evergreen broad leaf forest

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APPENDIX 2

Land Cover Parameter Values for Residential Medium Density (URMD) Land-Use Type Fraction of total impervious area 0.38 Fraction directly connected impervious area 0.3 Curb length density in urban (km/ha) 0.24 Wash-off coefficient for removal of constituents from impervious area (mm-1) 0.18 Max. amount of solids allowed to build up on impervious area (kg/ curb km) 225 Number of days for amount of solids on impervious areas to build up from 0kg/curb km to half the maximum allowed 0.75 Concentration of total Nitrogen in suspended solid load from impervious area (mg N/kg sed) 550 Concentration of total Phosphorus in suspended solid load from impervious areas (mg P/kg sed) 223 Concentration of nitrate in suspended solid load from impervious areas (mg NO3-N/kg sed) 7.2 Manning’s “n” value for overland flow 0.1 SCS runoff curve number for soil hydrologic group A 31 SCS runoff curve number for soil hydrologic group B 59 SCS runoff curve number for soil hydrologic group C 72 SCS runoff curve number for soil hydrologic group D 79 Curve number for moisture condition II 98

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APPENDIX 3

Soil Parameter Value for Gd16-2-3a-1201 Soil Type Soil hydrologic group D Maximum rooting depth(mm) 1000 Porosity fraction from which anions are excluded 0.5 Crack volume potential of soil 0.5 Texture Clay-loam Layer

1 2 Depth(mm) 300 1000 Bulk density(g/cm3) 1.4 1.4 Available water capacity of soil(mm H2O) 0.175 0.175 Ksat(mm/hr) 4.01 4.1 Organic carbon(% soil weight) 2.1 1.2 Clay(% soil weight) 33 37 Silt(% soil weight) 38 36 Sand(% soil weight) 29 27 Rock fragments (% total weight) 0 0 Soil albedo (moist) 0.0085 0.0484 Soil erodibility, K (metric ton m2hr) 0.2536 0.2536 Electrical conductivity (ds/m) 0 0

Soil Parameter Value for Nd5-1a-1567 Soil Type Soil hydrologic group C Maximum rooting depth(mm) 820 Porosity fraction from which anions are excluded 0.5 Crack volume potential of soil 0.5 Texture Sandy-loam Layer

1 2 Depth(mm) 300 1000 Bulk density(g/cm3) 1.0 1.1 Available water capacity of soil(mm H2O) 0.087 0.087 Ksat(mm/hr) 77.15 28.55 Organic carbon(% soil weight) 1.1 0.5 Clay(% soil weight) 15 27 Silt(% soil weight) 18 19 Sand(% soil weight) 67 53 Rock fragments (% total weight) 0 0 Soil albedo (moist) 0.0587 0.1867 Soil erodibility, K (metric ton m2hr) 0.2878 0.2878 Electrical conductivity (ds/m) 0 0

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Soil Parameter Value for Nd16-2-3a-1553 Soil Type Soil hydrologic group C Maximum rooting depth(mm) 1000 Porosity fraction from which anions are excluded 0.5 Crack volume potential of soil 0.5 Texture Clay-loam Layer

1 2 Depth(mm) 300 1000 Bulk density(g/cm3) 1.2 1.3 Available water capacity of soil(mm H2O) 0.175 0.175 Ksat(mm/hr) 13.12 8.73 Organic carbon(% soil weight) 1.9 0.5 Clay(% soil weight) 36 50 Silt(% soil weight) 28 22 Sand(% soil weight) 37 28 Rock fragments (% total weight) 0 0 Soil albedo (moist) 0.0125 0.1867 Soil erodibility, K (metric ton m2hr) 0.2846 0.2846 Electrical conductivity (ds/m) 0 0

Soil Parameter Value for Ap15-1a-1068 Soil Type Soil hydrologic group C Maximum rooting depth(mm) 820 Porosity fraction from which anions are excluded 0.5 Crack volume potential of soil 0.5 Texture Sandy-laom Layer

1 2 Depth(mm) 300 1000 Bulk density(g/cm3) 1.5 1.6 Available water capacity of soil(mm H2O) 0.087 0.087 Ksat(mm/hr) 13.4 3.45 Organic carbon(% soil weight) 0.8 0.3 Clay(% soil weight) 17 30 Silt(% soil weight) 18 17 Sand(% soil weight) 66 52 Rock fragments (% total weight) 0 0 Soil albedo (moist) 0.1047 0.2747 Soil erodibility, K (metric ton m2hr) 0.2504 0.2504 Electrical conductivity (ds/m) 0 0

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Soil Parameter Value for Bf6-1105 Soil Type Soil hydrologic group C Maximum rooting depth(mm) 910 Porosity fraction from which anions are excluded 0.5 Crack volume potential of soil 0.5 Texture Sandy-loam Layer

1 2 Depth(mm) 300 1000 Bulk density(g/cm3) 1.1 1.2 Available water capacity of soil(mm H2O) 0.16 0.16 Ksat(mm/hr) 40.36 0 Organic carbon(% soil weight) 2.1 0.6 Clay(% soil weight) 20 30 Silt(% soil weight) 21 19 Sand(% soil weight) 59 53 Rock fragments (% total weight) 0 0 Soil albedo (moist) 0.0085 0.154 Soil erodibility, K (metric ton m2hr) 0.2186 0.2186 Electrical conductivity (ds/m) 0 0

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APPENDIX 4 RAINFALL AND TEMPERATURE DATA

Data format: Rainfall = year + julian date + rainfall depth(mm) Temperature = year + julian date + max temp(xxx.x) + min temp(xxx.x)

Daily Rainfall (mm) Max. and Min. Daily Air Temperature (ºC)

1973001000 1973001032.2022.8 1973002000 1973002031.7023.3 1973003000 1973003031.1023.3 1973004000 1973004031.7022.8 1973005000 1973005033.3023.3 1973006000 1973006032.8023.9 1973007000 1973007031.7023.3 1973008000 1973008030.6023.3 1973009000 1973009030.0023.3 1973010000 1973010030.6020.6 1973011000 1973011030.6022.2 1973012000 1973012028.3022.2 1973013000 1973013028.9022.8 1973014000 1973014030.0021.7 1973015000 1973015029.4017.8 1973016000 1973016029.4016.1 1973017000 1973017030.6018.9 1973018000 1973018032.2018.3 1973019000 1973019032.8021.7 1973020000 1973020031.1023.3 1973021000 1973021032.2023.3 1973022000 1973022033.9020.0 1973023000 1973023033.3018.9 1973024000 1973024032.2022.2 1973025000 1973025032.2022.2 1973026000 1973026033.9022.2 1973027000 1973027034.4024.4 1973028000 1973028032.8022.8 1973029008 1973029032.8023.9 1973030000 1973030030.6023.3 1973031000 1973031031.1020.0 1973032000 1973032031.7018.9 1973033000 1973033031.7018.3 1973034000 1973034033.9018.3 1973035000 1973035033.9023.3 1973036000 1973036033.9024.4 1973037000 1973037035.6023.9 1973038000 1973038032.8024.4 1973039000 1973039028.9024.4 1973040000 1973040033.3023.3 1973041000 1973041031.7022.2 1973042000 1973042033.9022.8 1973043000 1973043033.9023.3 1973044000 1973044035.0022.8 1973045000 1973045034.4024.4

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1973046000 1973046033.9024.4 1973047000 1973047033.9024.4 1973048000 1973048035.6024.4 1973049000 1973049035.6024.4 1973050000 1973050032.8024.4 1973051000 1973051032.8024.4 1973052000 1973052030.6023.3 1973053000 1973053033.0020.6 1973054000 1973054035.6022.8 1973055000 1973055035.0024.4 1973056000 1973056033.9022.8 1973057000 1973057033.9024.4 1973058000 1973058033.9023.9 1973059002 1973059033.9024.4 1973060000 1973060032.2023.3 1973061000 1973061033.9024.4 1973062000 1973062033.9024.4 1973063000 1973063033.3021.1 1973064000 1973064031.1022.8 1973065000 1973065033.3022.8 1973066000 1973066033.9024.4 1973067000 1973067034.4024.4 1973068000 1973068033.9023.3 1973069000 1973069035.0023.9 1973070000 1973070035.0025.0 1973071000 1973071035.6025.6 1973072000 1973072033.9025.6 1973073005 1973073033.3023.3 1973074000 1973074032.8021.1 1973075000 1973075033.3024.4 1973076000 1973076035.0023.9 1973077000 1973077035.0023.3 1973078000 1973078034.4023.3 1973079000 1973079035.0023.9 1973080000 1973080035.0024.4 1973081001 1973081035.6023.3 1973082000 1973082033.9021.1 1973083000 1973083033.9024.4 1973084020 1973084034.4024.4 1973085000 1973085030.6020.6 1973086000 1973086031.7022.8 1973087000 1973087033.9023.9 1973088000 1973088027.2022.8 1973089000 1973089032.2021.7 1973090000 1973090034.4022.2 1973091003 1973091032.2023.9 1973092000 1973092032.8024.4 1973093014 1973093034.4023.9 1973094012 1973094032.2022.2 1973095000 1973095031.1019.4 1973096000 1973096033.9022.8 1973097000 1973097031.1023.3 1973098000 1973098032.8023.3 1973099000 1973099032.2023.9

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1973100000 1973100032.8023.3 1973101000 1973101032.8024.4 1973102000 1973102033.3024.4 1973103022 1973103031.1023.9 1973104000 1973104030.6020.6 1973105000 1973105030.6021.7 1973106000 1973106033.9021.7 1973107002 1973107032.8023.9 1973108008 1973108032.8021.7 1973109000 1973109032.2020.6 1973110000 1973110032.2023.9 1973111032 1973111029.4024.4 1973112000 1973112030.0019.4 1973113000 1973113031.7020.6 1973114000 1973114031.7020.6 1973115000 1973115031.7023.3 1973116000 1973116034.4022.2 1973117000 1973117033.3025.0 1973118000 1973118029.4023.9 1973119004 1973119031.7022.2 1973120000 1973120028.9019.4 1973121000 1973121033.3022.2 1973122000 1973122030.6021.7 1973123000 1973123032.2022.8 1973124006 1973124031.1025.6 1973125009 1973125032.8021.1 1973126013 1973126033.0021.1 1973127000 1973127029.4020.6 1973128000 1973128031.1023.3 1973129000 1973129031.1023.3 1973130047 1973130031.1022.8 1973131007 1973131031.1019.4 1973132000 1973132028.3020.0 1973133000 1973133029.4020.6 1973134000 1973134031.7022.2 1973135021 1973135031.1022.8 1973136013 1973136030.6021.1 1973137000 1973137028.9021.7 1973138000 1973138030.0022.2 1973139000 1973139030.0022.8 1973140000 1973140030.6022.8 1973141000 1973141030.0023.3 1973142000 1973142030.0020.0 1973143070 1973143028.9022.8 1973144004 1973144028.3018.9 1973145000 1973145026.7020.0 1973146000 1973146030.0021.7 1973147000 1973147030.6022.8 1973148048 1973148028.3023.3 1973149000 1973149029.4020.0 1973150021 1973150030.0021.7 1973151000 1973151029.4018.9 1973152043 1973152029.4023.3 1973153000 1973153028.3020.0

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1973154000 1973154030.0022.8 1973155037 1973155029.4023.3 1973156003 1973156027.8020.0 1973157009 1973157027.8021.1 1973158009 1973158025.6019.4 1973159061 1973159028.9020.0 1973160000 1973160030.0018.9 1973161061 1973161030.0020.0 1973162000 1973162028.9020.0 1973163004 1973163029.4022.2 1973164012 1973164027.8022.2 1973165000 1973165028.9021.1 1973166000 1973166030.0022.8 1973167007 1973167025.0020.6 1973168000 1973168028.3020.0 1973169058 1973169027.2022.2 1973170000 1973170028.3018.3 1973171000 1973171029.4022.2 1973172000 1973172029.4022.8 1973173012 1973173028.9022.8 1973174000 1973174027.2020.0 1973175003 1973175027.8020.6 1973176000 1973176029.4020.6 1973177019 1973177027.8020.6 1973178003 1973178028.3020.6 1973179000 1973179027.2019.4 1973180000 1973180027.8020.0 1973181020 1973181027.8021.7 1973182022 1973182025.0021.7 1973183000 1973183027.8020.0 1973184000 1973184029.4020.6 1973185000 1973185028.9022.2 1973186000 1973186030.0022.2 1973187000 1973187029.4020.6 1973188034 1973188027.8021.7 1973189000 1973189028.3018.9 1973190000 1973190028.9020.0 1973191000 1973191028.9022.2 1973192000 1973192028.3021.7 1973193000 1973193027.8021.1 1973194000 1973194029.4020.0 1973195000 1973195028.9021.7 1973196001 1973196028.9021.1 1973197001 1973197026.1021.7 1973198000 1973198027.8021.7 1973199013 1973199025.6021.7 1973200000 1973200028.3020.0 1973201000 1973201027.8021.7 1973202002 1973202028.3022.2 1973203000 1973203028.3021.1 1973204000 1973204028.9022.2 1973205015 1973205023.3022.2 1973206011 1973206026.7020.0 1973207002 1973207025.0020.6

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1973208001 1973208028.3021.1 1973209002 1973209026.1021.7 1973210000 1973210027.8021.1 1973211000 1973211026.7021.7 1973212000 1973212027.8018.9 1973213003 1973213027.8020.0 1973214000 1973214028.9020.6 1973215006 1973215028.9020.6 1973216000 1973216028.9021.7 1973217006 1973217028.9021.7 1973218021 1973218028.3021.1 1973219001 1973219027.8020.6 1973220000 1973220027.2020.6 1973221000 1973221026.7021.1 1973222002 1973222025.0020.0 1973223003 1973223026.7020.6 1973224001 1973224027.2020.6 1973225000 1973225026.7021.1 1973226000 1973226028.3021.1 1973227000 1973227026.7021.7 1973228000 1973228026.7021.1 1973229000 1973229028.3020.6 1973230000 1973230028.9021.1 1973231003 1973231029.4021.7 1973232000 1973232028.9020.6 1973233019 1973233027.8021.7 1973234000 1973234028.3021.1 1973235000 1973235027.2021.7 1973236000 1973236028.9021.7 1973237025 1973237028.9021.7 1973238004 1973238026.7019.4 1973239001 1973239028.3021.1 1973240000 1973240028.3020.6 1973241021 1973241028.9021.1 1973242019 1973242028.9019.4 1973243000 1973243027.4020.6 1973244018 1973244027.2021.7 1973245066 1973245028.9020.6 1973246010 1973246027.2020.0 1973247002 1973247023.3020.6 1973248000 1973248027.2019.4 1973249010 1973249029.4021.7 1973250000 1973250026.7019.4 1973251122 1973251028.3020.0 1973252047 1973252025.6018.9 1973253000 1973253027.8020.0 1973254002 1973254026.7021.1 1973255011 1973255027.8019.4 1973256030 1973256025.0020.6 1973257001 1973257027.8020.6 1973258016 1973258028.3021.1 1973259024 1973259027.8019.4 1973260000 1973260025.6018.9 1973261002 1973261028.3019.4

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1973262000 1973262028.9022.2 1973263000 1973263029.4021.7 1973264000 1973264029.4021.1 1973265000 1973265028.9022.2 1973266002 1973266029.4021.7 1973267013 1973267029.4021.7 1973268000 1973268027.2020.6 1973269011 1973269028.3020.6 1973270000 1973270027.8021.1 1973271061 1973271027.8018.9 1973272000 1973272028.3020.0 1973273000 1973273028.9019.4 1973274000 1973274028.3019.4 1973275003 1973275029.4020.0 1973276010 1973276027.2020.0 1973277012 1973277027.8018.9 1973278025 1973278029.4021.1 1973279000 1973279029.4019.4 1973280026 1973280028.9017.8 1973281000 1973281028.3019.4 1973282017 1973282028.9020.6 1973283007 1973283029.4021.7 1973284000 1973284030.0019.4 1973285009 1973285030.0022.2 1973286000 1973286028.9022.2 1973287000 1973287028.9022.2 1973288000 1973288029.4022.2 1973289037 1973289030.0022.2 1973290000 1973290029.4021.7 1973291000 1973291029.4022.2 1973292003 1973292027.8020.6 1973293003 1973293027.8021.7 1973294000 1973294030.0020.6 1973295000 1973295030.0021.1 1973296000 1973296028.3019.4 1973297017 1973297027.8021.1 1973298001 1973298028.3021.1 1973299000 1973299028.9021.1 1973300000 1973300030.0020.6 1973301001 1973301031.1020.6 1973302000 1973302028.9020.6 1973303000 1973303029.4022.2 1973304030 1973304030.0022.2 1973305000 1973305030.6021.1 1973306000 1973306030.6021.7 1973307000 1973307030.6022.2 1973308000 1973308030.6022.2 1973309000 1973309030.6022.2 1973310000 1973310029.4021.7 1973311000 1973311030.0021.9 1973312002 1973312030.0020.0 1973313000 1973313030.0018.3 1973314000 1973314031.1016.1 1973315000 1973315032.2016.1

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1973316000 1973316031.1015.6 1973317000 1973317031.7016.7 1973318000 1973318031.1016.7 1973319000 1973319030.6017.8 1973320000 1973320031.7021.1 1973321000 1973321031.1017.2 1973322000 1973322031.7019.4 1973323000 1973323030.6020.0 1973324000 1973324031.1020.6 1973325000 1973325031.1022.2 1973326000 1973326031.7020.0 1973327000 1973327031.1015.6 1973328000 1973328031.1017.2 1973329000 1973329029.4019.4 1973330000 1973330030.6018.3 1973331000 1973331031.1018.3 1973332000 1973332031.1016.1 1973333000 1973333031.7018.9 1973334000 1973334031.7022.2 1973335000 1973335031.1018.9 1973336000 1973336031.1022.2 1973337000 1973337030.6022.2 1973338000 1973338031.7022.8 1973339000 1973339031.1021.1 1973340000 1973340031.7020.6 1973341000 1973341027.8018.3 1973342000 1973342030.0021.1 1973343033 1973343030.6022.2 1973344000 1973344030.6022.8 1973345000 1973345030.0021.7 1973346000 1973346028.3022.8 1973347000 1973347029.4020.0 1973348000 1973348030.0021.1 1973349000 1973349030.6022.8 1973350000 1973350030.0021.7 1973351000 1973351031.1021.1 1973352000 1973352030.6022.2 1973353000 1973353030.6021.1 1973354000 1973354031.7022.8 1973355000 1973355031.7022.8 1973356000 1973356031.7022.8 1973357000 1973357031.1021.7 1973358000 1973358030.6022.2 1973359000 1973359031.1022.2 1973360000 1973360031.1021.7 1973361000 1973361030.6018.9 1973362000 1973362030.0019.4 1973363000 1973363032.2021.1 1973364000 1973364030.0023.3 1973365000 1973365030.0023.0 1974001000 1974001030.6021.1 1974002000 1974002031.1022.8 1974003000 1974003032.2021.1 1974004000 1974004031.7023.3

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1974005000 1974005031.1021.7 1974006000 1974006031.7022.2 1974007000 1974007029.4016.1 1974008000 1974008028.9017.2 1974009000 1974009028.9019.4 1974010000 1974010030.0019.4 1974011000 1974011030.0017.8 1974012000 1974012028.9015.6 1974013000 1974013031.1012.2 1974014000 1974014030.6015.0 1974015000 1974015029.4016.7 1974016000 1974016028.9018.3 1974017000 1974017027.2018.9 1974018000 1974018030.6016.1 1974019000 1974019030.0016.7 1974020000 1974020030.6018.3 1974021000 1974021032.2018.3 1974022000 1974022031.1016.7 1974023000 1974023030.6017.2 1974024000 1974024032.2017.8 1974025000 1974025032.2021.7 1974026000 1974026032.2022.8 1974027000 1974027032.8021.1 1974028000 1974028031.7020.6 1974029000 1974029031.7022.2 1974030000 1974030022.8022.8 1974031000 1974031033.3021.7 1974032000 1974032032.2020.1 1974033000 1974033033.9017.2 1974034000 1974034033.9018.9 1974035000 1974035034.4017.7 1974036000 1974036033.9018.3 1974037000 1974037032.2022.8 1974038000 1974038032.8022.2 1974039000 1974039032.8023.3 1974040000 1974040033.4023.3 1974041000 1974041034.4023.3 1974042000 1974042034.4021.7 1974043000 1974043031.1021.7 1974044000 1974044031.7020.6 1974045000 1974045033.3022.8 1974046000 1974046032.8023.9 1974047000 1974047033.3023.3 1974048000 1974048032.8023.9 1974049000 1974049032.2022.8 1974050000 1974050033.3022.8 1974051000 1974051032.8023.3 1974052000 1974052033.3022.8 1974053000 1974053032.8023.3 1974054000 1974054032.2020.6 1974055000 1974055033.3020.0 1974056000 1974056032.2022.8 1974057000 1974057026.7023.3 1974058000 1974058033.3023.3

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1974059000 1974059033.3028.8 1974060000 1974060033.3023.9 1974061000 1974061032.8022.8 1974062000 1974062034.4032.8 1974063000 1974063034.4023.3 1974064000 1974064034.4023.3 1974065000 1974065035.0023.3 1974066000 1974066033.9023.9 1974067000 1974067033.3023.3 1974068000 1974068033.3023.9 1974069000 1974069033.9023.3 1974070000 1974070032.2022.2 1974071018 1974071031.1023.3 1974072000 1974072030.0013.9 1974073000 1974073032.2020.0 1974074000 1974074031.7022.8 1974075003 1974075032.2022.2 1974076000 1974076032.8023.3 1974077000 1974077033.3023.3 1974078000 1974078033.3023.3 1974079000 1974079033.9023.9 1974080000 1974080031.1023.3 1974081000 1974081032.8023.9 1974082000 1974082032.2021.7 1974083000 1974083034.4023.3 1974084000 1974084032.8023.3 1974085000 1974085032.8022.8 1974086000 1974086033.3023.9 1974087018 1974087031.7022.8 1974088000 1974088031.1021.1 1974089000 1974089032.2022.8 1974090000 1974090031.7022.8 1974091000 1974091033.3021.7 1974092000 1974092031.1021.1 1974093005 1974093030.6021.7 1974094000 1974094030.0021.1 1974095000 1974095031.1020.6 1974096047 1974096030.0023.3 1974097000 1974097028.9019.4 1974098000 1974098030.6020.6 1974099025 1974099031.1023.3 1974100000 1974100030.6024.4 1974101000 1974101031.1022.8 1974102010 1974102031.1022.8 1974103000 1974103028.9019.4 1974104000 1974104031.7022.2 1974105000 1974105032.2023.9 1974106000 1974106031.1023.3 1974107002 1974107029.4023.3 1974108000 1974108030.0021.7 1974109006 1974109030.0023.3 1974110000 1974110031.1020.0 1974111000 1974111031.1022.2 1974112000 1974112031.1020.6

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1974113007 1974113031.1021.1 1974114000 1974114030.1020.6 1974115000 1974115030.0021.1 1974116000 1974116031.1021.7 1974117000 1974117031.7023.3 1974118032 1974118032.2022.8 1974119000 1974119029.4020.6 1974120000 1974120031.1023.9 1974121035 1974121030.0023.3 1974122000 1974122028.9020.0 1974123009 1974123029.4021.1 1974124009 1974124026.7020.0 1974125000 1974125028.3020.0 1974126002 1974126029.4022.2 1974127018 1974127028.9021.7 1974128000 1974128027.2021.1 1974129000 1974129028.3020.6 1974130000 1974130028.3022.2 1974131008 1974131030.0021.7 1974132000 1974132031.1019.4 1974133003 1974133028.9020.6 1974134046 1974134030.0019.4 1974135000 1974135029.4019.4 1974136029 1974136029.4021.7 1974137000 1974137028.9020.0 1974138000 1974138030.0021.7 1974139000 1974139030.6023.3 1974140042 1974140030.0022.8 1974141000 1974141026.7019.4 1974142013 1974142030.0021.7 1974143000 1974143029.4018.9 1974144000 1974144028.9023.3 1974145000 1974145030.0023.3 1974146042 1974146031.1022.3 1974147000 1974147027.2020.0 1974148000 1974148028.9021.7 1974149000 1974149030.0022.8 1974150000 1974150030.6022.8 1974151000 1974151029.4021.7 1974152003 1974152028.3021.1 1974153000 1974153028.3021.1 1974154000 1974154029.4021.1 1974155004 1974155028.9022.8 1974156014 1974156028.3021.7 1974157000 1974157027.2021.7 1974158000 1974158028.9020.6 1974159000 1974159030.0021.7 1974160029 1974160030.0022.2 1974161024 1974161028.9020.0 1974162000 1974162028.9019.4 1974163000 1974163030.0021.7 1974164000 1974164029.4023.3 1974165000 1974165029.4021.7 1974166000 1974166030.0022.8

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1974167038 1974167030.0022.8 1974168000 1974168027.2020.6 1974169000 1974169028.9021.7 1974170000 1974170029.4022.2 1974171011 1974171026.7022.2 1974172000 1974172025.6018.9 1974173000 1974173026.7020.0 1974174000 1974174028.9020.0 1974175000 1974175028.9020.6 1974176000 1974176028.3021.7 1974177033 1974177028.3021.1 1974178000 1974178027.8019.4 1974179009 1974179028.3021.1 1974180022 1974180028.3020.6 1974181000 1974181023.9017.8 1974182000 1974182026.7020.0 1974183000 1974183027.2021.1 1974184000 1974184025.6021.1 1974185005 1974185026.1020.6 1974186009 1974186025.6020.6 1974187009 1974187027.8020.6 1974188003 1974188026.1020.0 1974189000 1974189027.2020.0 1974190000 1974190027.2020.0 1974191001 1974191025.6020.0 1974192000 1974192027.8021.1 1974193000 1974193028.3021.1 1974194000 1974194026.7021.1 1974195023 1974195027.8020.6 1974196001 1974196025.6019.4 1974197016 1974197026.7020.6 1974198030 1974198025.6020.6 1974199000 1974199026.7020.0 1974200001 1974200027.2020.6 1974201000 1974201025.6021.7 1974202001 1974202027.2020.0 1974203026 1974203027.8020.6 1974204000 1974204028.3020.0 1974205015 1974205028.3020.6 1974206000 1974206027.2020.6 1974207010 1974207028.3020.0 1974208028 1974208027.8020.0 1974209001 1974209027.8021.1 1974210000 1974210027.8021.7 1974211000 1974211027.2017.8 1974212000 1974212028.3020.0 1974213014 1974213028.3020.6 1974214019 1974214027.2021.1 1974215000 1974215027.8021.1 1974216000 1974216028.3021.1 1974217004 1974217025.7021.1 1974218000 1974218029.4020.0 1974219002 1974219029.4020.6 1974220022 1974220029.4021.1

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1974221001 1974221026.7022.2 1974222000 1974222025.7019.4 1974223002 1974223028.3021.1 1974224000 1974224027.2021.7 1974225003 1974225026.7021.1 1974226009 1974226027.2021.7 1974227009 1974227026.7021.7 1974228000 1974228026.1021.1 1974229000 1974229026.1021.1 1974230000 1974230024.4020.6 1974231000 1974231027.2020.6 1974232002 1974232028.9019.4 1974233000 1974233027.2021.1 1974234000 1974234028.3021.1 1974235023 1974235027.8020.6 1974236000 1974236029.4020.6 1974237002 1974237028.3020.6 1974238001 1974238027.8020.6 1974239000 1974239026.1020.6 1974240002 1974240027.2021.1 1974241009 1974241025.0021.1 1974242010 1974242023.9021.1 1974243000 1974243026.1020.6 1974244018 1974244028.3020.6 1974245022 1974245028.3020.0 1974246003 1974246025.6021.1 1974247044 1974247026.1020.6 1974248032 1974248026.1020.0 1974249001 1974249027.2020.6 1974250014 1974250026.1020.6 1974251000 1974251025.6020.6 1974252033 1974252025.0018.9 1974253012 1974253028.3021.1 1974254019 1974254026.1020.0 1974255045 1974255028.9020.6 1974256000 1974256027.8020.0 1974257080 1974257025.6020.6 1974258035 1974258028.3021.1 1974259009 1974259026.7020.0 1974260004 1974260026.7019.4 1974261017 1974261026.7020.0 1974262000 1974262027.8021.1 1974263000 1974263028.3019.4 1974264023 1974264028.3020.6 1974265001 1974265029.4021.1 1974266008 1974266028.3020.0 1974267000 1974267027.2021.7 1974268004 1974268027.8020.6 1974269000 1974269026.1020.6 1974270005 1974270028.3018.9 1974271000 1974271028.3020.6 1974272000 1974272028.3020.6 1974273009 1974273028.3021.1 1974274000 1974274027.8021.1

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1974275001 1974275027.8020.0 1974276063 1974276027.2020.6 1974277000 1974277028.9021.1 1974278000 1974278026.7018.9 1974279015 1974279027.8021.1 1974280011 1974280028.9021.1 1974281036 1974281025.0020.0 1974282026 1974282027.8020.6 1974283000 1974283028.9018.9 1974284025 1974284027.2018.9 1974285000 1974285027.2021.1 1974286020 1974286022.8017.8 1974287014 1974287027.2019.4 1974288000 1974288027.2019.4 1974289000 1974289027.8020.0 1974290000 1974290028.9021.7 1974291000 1974291028.3021.7 1974292018 1974292028.9021.7 1974293001 1974293029.4022.2 1974294019 1974294029.4019.4 1974295000 1974295029.4020.6 1974296000 1974296029.4019.4 1974297015 1974297027.2021.1 1974298000 1974298028.9021.7 1974299000 1974299028.3021.1 1974300027 1974300030.0021.7 1974301000 1974301030.0022.2 1974302001 1974302027.8021.1 1974303000 1974303028.3016.7 1974304000 1974304028.3021.1 1974305000 1974305029.4021.7 1974306002 1974306030.0022.2 1974307000 1974307028.3021.7 1974308000 1974308028.9021.1 1974309000 1974309030.6021.7 1974310000 1974310029.4021.7 1974311000 1974311030.0021.7 1974312000 1974312029.4021.7 1974313000 1974313029.4022.2 1974314000 1974314030.6022.8 1974315000 1974315030.6022.2 1974316000 1974316031.1022.2 1974317000 1974317031.1022.2 1974318000 1974318028.3022.8 1974319000 1974319030.6022.2 1974320000 1974320030.6022.8 1974321000 1974321030.0018.9 1974322000 1974322030.6020.6 1974323000 1974323030.6021.7 1974324000 1974324030.6018.9 1974325000 1974325031.1017.8 1974326000 1974326031.1016.1 1974327000 1974327030.6016.7 1974328000 1974328031.1019.4

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1974329000 1974329031.7018.9 1974330000 1974330031.7020.6 1974331000 1974331030.6020.0 1974332000 1974332031.7019.4 1974333000 1974333031.1018.3 1974334000 1974334031.1017.8 1974335000 1974335013.1018.3 1974336000 1974336029.4022.2 1974337000 1974337028.9020.6 1974338000 1974338028.3017.8 1974339000 1974339029.4017.2 1974340000 1974340031.1019.4 1974341000 1974341030.6017.2 1974342000 1974342030.6016.1 1974343000 1974343030.6016.7 1974344000 1974344031.1015.6 1974345000 1974345031.7015.0 1974346000 1974346032.2015.0 1974347000 1974347032.2015.0 1974348000 1974348031.1018.9 1974349000 1974349031.1018.3 1974350000 1974350031.7016.7 1974351000 1974351030.0018.3 1974352000 1974352031.1018.3 1974353000 1974353032.2020.0 1974354000 1974354032.2021.7 1974355000 1974355030.0022.2 1974356000 1974356031.1023.3 1974357000 1974357032.2022.8 1974358000 1974358029.4022.2 1974359000 1974359030.6018.9 1974360000 1974360029.4019.4 1974361000 1974361028.9018.9 1974362000 1974362029.4017.8 1974363000 1974363030.0016.1 1974364000 1974364031.1016.7 1974365000 1974365031.1016.7 1975001000 1975001031.1015.0 1975002000 1975002031.7015.6 1975003000 1975003031.1014.4 1975004000 1975004032.2015.0 1975005000 1975005033.3017.2 1975006000 1975006031.1016.1 1975007000 1975007032.8015.0 1975008000 1975008032.8015.6 1975009000 1975009032.2016.7 1975010000 1975010031.1017.8 1975011000 1975011030.6016.1 1975012000 1975012028.9018.9 1975013000 1975013028.3018.3 1975014000 1975014029.4019.4 1975015000 1975015030.6018.9 1975016000 1975016031.1018.9 1975017000 1975017030.6016.7

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1975072000 1975072034.4023.9 1975073000 1975073033.3023.9 1975074000 1975074032.2023.9 1975075000 1975075032.2023.9 1975076000 1975076032.8023.3 1975077001 1975077032.8022.2 1975078000 1975078033.3022.8 1975079000 1975079032.2023.3 1975080000 1975080033.3022.8 1975081000 1975081032.8023.3 1975082002 1975082030.6022.8 1975083011 1975083031.1019.4 1975084029 1975084032.2019.4 1975085000 1975085031.7023.3 1975086000 1975086032.2023.3 1975087000 1975087032.2023.9 1975088000 1975088032.8023.3 1975089000 1975089032.2023.3 1975090000 1975090029.4023.9 1975091000 1975091032.8021.7 1975092000 1975092033.3023.3 1975093000 1975093032.2023.3 1975094000 1975094032.2022.8 1975095000 1975095032.2023.9 1975096032 1975096026.7023.9 1975097000 1975097030.6020.6 1975098000 1975098031.1021.1 1975099000 1975099031.7023.3 1975100004 1975100032.8023.3 1975101000 1975101031.1020.6 1975102000 1975102032.2023.9 1975103000 1975103032.8024.4 1975104000 1975104031.7023.9 1975105000 1975105031.7022.8 1975106000 1975106032.8023.9 1975107000 1975107031.7026.7 1975108013 1975108027.2023.3 1975109000 1975109030.0020.0 1975110000 1975110028.3021.7 1975111002 1975111027.8022.8 1975112000 1975112022.9018.9 1975113000 1975113032.2022.2 1975114004 1975114029.4023.3 1975115009 1975115032.8021.1 1975116000 1975116031.1021.1 1975117000 1975117031.7023.3 1975118005 1975118031.7023.3 1975119000 1975119028.9020.0 1975120000 1975120032.8021.7 1975121024 1975121028.9021.1 1975122024 1975122030.6022.8 1975123005 1975123027.2019.4 1975124000 1975124030.6020.0 1975125011 1975125030.0022.8

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1975126000 1975126030.0020.6 1975127021 1975127030.7022.8 1975128000 1975128028.3020.0 1975129000 1975129029.4023.3 1975130000 1975130030.0021.1 1975131000 1975131029.4022.8 1975132000 1975132029.4022.8 1975133000 1975133030.0021.7 1975134000 1975134031.1022.2 1975135000 1975135030.6023.3 1975136005 1975136030.0021.7 1975137000 1975137029.4020.6 1975138000 1975138028.9020.6 1975139021 1975139028.3019.4 1975140000 1975140030.0019.4 1975141022 1975141029.4022.8 1975142001 1975142028.9018.9 1975143065 1975143030.6020.0 1975144000 1975144028.9020.0 1975145000 1975145028.9022.2 1975146000 1975146030.0021.1 1975147000 1975147030.0022.8 1975148000 1975148029.4022.8 1975149019 1975149028.9023.3 1975150000 1975150028.9018.9 1975151007 1975151029.4020.6 1975152000 1975152028.3021.7 1975153000 1975153028.3021.7 1975154005 1975154028.3021.7 1975155000 1975155029.4018.9 1975156016 1975156030.6022.2 1975157000 1975157031.7019.4 1975158022 1975158030.0020.0 1975159000 1975159027.2019.4 1975160022 1975160026.7020.6 1975161000 1975161027.2021.1 1975162000 1975162030.0020.6 1975163000 1975163029.4022.2 1975164017 1975164029.4022.2 1975165000 1975165023.3018.9 1975166000 1975166027.2019.4 1975167003 1975167029.4021.1 1975168000 1975168028.3019.4 1975169000 1975169028.9021.7 1975170025 1975170028.9021.7 1975171021 1975171028.9020.0 1975172023 1975172028.3020.6 1975173001 1975173028.3020.6 1975174000 1975174028.3021.7 1975175000 1975175029.4022.2 1975176000 1975176030.0020.6 1975177004 1975177028.9022.2 1975178000 1975178028.9020.0 1975179000 1975179028.9021.7

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1975180033 1975180028.9021.7 1975181022 1975181027.8022.2 1975182013 1975182027.2020.0 1975183000 1975183028.3021.1 1975184016 1975184025.6021.1 1975185011 1975185029.4020.0 1975186022 1975186027.8021.7 1975187000 1975187025.0020.0 1975188000 1975188026.1020.0 1975189006 1975189028.9020.6 1975190001 1975190027.8020.0 1975191000 1975191027.8020.0 1975192004 1975192025.6020.6 1975193002 1975193027.8020.6 1975194006 1975194025.6020.0 1975195002 1975195028.9020.6 1975196006 1975196027.8021.1 1975197009 1975197026.7021.7 1975198018 1975198023.9021.1 1975199000 1975199027.8020.6 1975200002 1975200028.9021.7 1975201021 1975201027.8021.7 1975202000 1975202026.7020.0 1975203000 1975203026.7020.6 1975204000 1975204027.2020.0 1975205002 1975205027.2020.0 1975206000 1975206027.2019.4 1975207000 1975207026.7020.0 1975208000 1975208027.2020.6 1975209000 1975209026.1021.1 1975210004 1975210025.6020.6 1975211000 1975211027.2021.1 1975212002 1975212024.4021.1 1975213002 1975213028.3020.6 1975214000 1975214028.3020.0 1975215000 1975215028.3020.6 1975216000 1975216028.3021.7 1975217033 1975217024.4021.1 1975218027 1975218023.9018.9 1975219001 1975219026.7020.6 1975220027 1975220026.1020.6 1975221002 1975221025.6021.1 1975222011 1975222026.1020.0 1975223005 1975223027.8020.6 1975224016 1975224025.6021.1 1975225000 1975225024.4020.6 1975226014 1975226026.1020.6 1975227000 1975227026.7020.0 1975228002 1975228027.8020.6 1975229001 1975229027.2020.6 1975230000 1975230026.7020.6 1975231001 1975231026.7020.0 1975232000 1975232023.9020.0 1975233000 1975233025.6020.0

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1975234000 1975234025.6020.0 1975235000 1975235025.0020.6 1975236003 1975236026.7020.0 1975237007 1975237023.3020.0 1975238000 1975238026.1019.4 1975239000 1975239026.7020.0 1975240000 1975240026.7019.4 1975241000 1975241027.8020.0 1975242000 1975242026.1020.6 1975243000 1975243025.6020.6 1975244000 1975244024.4020.0 1975245000 1975245027.8020.0 1975246000 1975246026.7020.6 1975247000 1975247027.8019.4 1975248004 1975248023.3020.6 1975249022 1975249026.7019.4 1975250037 1975250025.6020.0 1975251026 1975251022.8019.4 1975252000 1975252025.6020.0 1975253005 1975253026.7020.0 1975254000 1975254023.9020.0 1975255020 1975255027.2020.0 1975256000 1975256026.7020.6 1975257002 1975257027.2021.1 1975258012 1975258026.1020.6 1975259010 1975259026.7020.6 1975260001 1975260026.7020.6 1975261013 1975261028.3021.1 1975262033 1975262027.8019.4 1975263014 1975263027.2020.6 1975264002 1975264028.9020.0 1975265000 1975265027.8020.6 1975266035 1975266027.2021.7 1975267000 1975267026.7018.9 1975268022 1975268027.2019.4 1975269026 1975269025.0021.1 1975270000 1975270028.3019.4 1975271001 1975271027.2021.7 1975272017 1975272028.3021.1 1975273026 1975273024.4018.9 1975274000 1975274026.7018.9 1975275038 1975275027.8021.1 1975276000 1975276028.3017.8 1975277015 1975277028.9021.7 1975278022 1975278028.3019.4 1975279000 1975279025.6018.9 1975280004 1975280027.2020.6 1975281017 1975281027.8020.6 1975282000 1975282026.7019.4 1975283013 1975283028.9019.4 1975284000 1975284027.2019.4 1975285000 1975285028.9020.0 1975286008 1975286027.2022.2 1975287000 1975287028.3021.7

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1975242000 1975242030.6015.6 1975343000 1975343030.0016.7 1975344000 1975344030.6016.7 1975345000 1975345030.6017.2 1975346000 1975346031.7013.9 1975347000 1975347032.2014.4 1975348000 1975348032.2015.6 1975349000 1975349032.2014.4 1975350000 1975350031.1015.0 1975351000 1975351031.7013.9 1975352000 1975352031.1015.0 1975353000 1975353032.2017.2 1975354000 1975354031.7018.9 1975355000 1975355030.6022.2 1975356000 1975356030.6022.2 1975357016 1975357031.1021.7 1975358000 1975358027.8020.0 1975359000 1975359031.1019.4 1975360000 1975360030.6019.4 1975361000 1975361030.0015.6 1975362000 1975362029.4017.2 1975363000 1975363029.4017.8 1975364000 1975364029.4018.3 1975365000 1975365029.4018.3 1976001000 1976001030.0016.7 1976002000 1976002030.6015.0 1976003000 1976003031.1014.4 1976004000 1976004031.1015.6 1976005000 1976005031.7017.2 1976006000 1976006032.8017.8 1976007000 1976007032.2018.3 1976008000 1976008031.7021.1 1976009000 1976009031.7021.7 1976010000 1976010031.7022.8 1976011000 1976011031.1022.8 1976012000 1976012031.1022.2 1976013000 1976013031.7020.6 1976014000 1976014031.1020.6 1976015000 1976015032.2020.6 1976016000 1976016033.3021.1 1976017000 1976017031.1021.1 1976018000 1976018028.9020.0 1976019000 1976019030.6018.9 1976020000 1976020030.6018.3 1976021000 1976021030.6016.7 1976022000 1976022030.6019.4 1976023000 1976023029.4016.7 1976024000 1976024029.4019.4 1976025000 1976025031.7016.1 1976026000 1976026032.2016.7 1976027000 1976027031.7020.0 1976028000 1976028031.7022.2 1976029000 1976029034.4022.2 1976030000 1976030032.8022.8

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1977097000 1977097033.3024.4 1977098000 1977098032.2023.3 1977099000 1977099033.3022.2 1977100000 1977100033.3023.9 1977101000 1977101033.3023.9 1977102000 1977102033.3023.3 1977103016 1977103028.9023.9 1977104000 1977104031.7019.4 1977105000 1977105031.1022.8 1977106000 1977106032.2023.3 1977107000 1977107032.8024.4 1977108000 1977108033.9024.4 1977109005 1977109032.2022.8 1977110000 1977110032.2022.8 1977111000 1977111033.9023.9 1977112000 1977112030.0025.0 1977113000 1977113033.9023.3 1977114000 1977114031.7026.7 1977115001 1977115032.2024.4 1977116000 1977116027.2021.7 1977117000 1977117031.7023.3 1977118000 1977118033.3023.9 1977119006 1977119032.2023.3 1977120000 1977120026.7021.7 1977121000 1977121032.8022.8 1977122000 1977122032.8022.8 1977123012 1977123032.8022.8 1977124000 1977124030.6021.7 1977125000 1977125031.1022.8 1977126000 1977126031.1023.3 1977127000 1977127031.7022.8 1977128005 1977128031.1022.2 1977129021 1977129028.3021.1 1977130000 1977130031.1020.0 1977131000 1977131030.0020.6 1977132000 1977132031.7022.8 1977133000 1977133031.1023.3 1977134000 1977134031.7023.3 1977135000 1977135030.6022.8 1977136000 1977136032.2023.9 1977137000 1977137028.9023.3 1977138008 1977138028.3023.9 1977139000 1977139030.6022.2 1977140000 1977140034.4021.1 1977141002 1977141031.1021.7 1977142000 1977142030.6021.1 1977143000 1977143031.7022.2 1977144000 1977144032.2022.2 1977145000 1977145032.8022.2 1977146055 1977146031.1022.2 1977147001 1977147027.2018.9 1977148000 1977148029.4019.4 1977149000 1977149029.4019.4 1977150000 1977150030.6021.7

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1977205012 1977205028.3020.6 1977206000 1977206024.4018.3 1977207001 1977207027.2018.9 1977208000 1977208028.3021.1 1977209018 1977209028.3021.1 1977210001 1977210025.0021.1 1977211000 1977211027.2021.7 1977212000 1977212027.2021.1 1977213000 1977213028.3021.1 1977214000 1977214026.1021.1 1977215002 1977215027.2020.0 1977216000 1977216026.1020.0 1977217000 1977217026.1020.0 1977218000 1977218027.2020.0 1977219001 1977219025.0020.6 1977220000 1977220025.6020.6 1977221000 1977221025.0020.0 1977222001 1977222028.3020.6 1977223041 1977223026.1021.1 1977224008 1977224023.3020.6 1977225000 1977225025.0020.6 1977226000 1977226027.8020.0 1977227014 1977227027.8020.6 1977228000 1977228027.8020.6 1977229019 1977229028.9020.6 1977230000 1977230028.9020.6 1977231000 1977231027.8021.1 1977232003 1977232027.2021.7 1977233022 1977233026.1020.0 1977234002 1977234025.6021.1 1977235002 1977235026.7021.1 1977236000 1977236027.2021.1 1977237004 1977237027.2021.1 1977238003 1977238027.2021.1 1977239000 1977239025.6021.1 1977240000 1977240026.7021.1 1977241002 1977241025.0021.1 1977242008 1977242026.7020.6 1977243000 1977243027.2021.1 1977244013 1977244027.8021.1 1977245007 1977245026.1021.1 1977246000 1977246027.2020.6 1977247000 1977247027.2021.1 1977248000 1977248027.2021.1 1977249001 1977249025.5021.1 1977250001 1977250027.8021.1 1977251000 1977251027.8021.1 1977252010 1977252027.8021.1 1977253000 1977253028.3020.6 1977254057 1977254028.3022.2 1977255001 1977255028.9023.9 1977256011 1977256027.8021.7 1977257021 1977257028.9021.1 1977258004 1977258026.7020.0

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1977259000 1977259026.1020.6 1977260000 1977260028.9021.1 1977261000 1977261028.9021.1 1977262014 1977262028.3021.7 1977263017 1977263028.3019.4 1977264010 1977264028.3022.2 1977265001 1977265028.3021.7 1977266000 1977266028.9020.6 1977267000 1977267028.3021.7 1977268011 1977268027.2021.7 1977269002 1977269027.2021.1 1977270053 1977270028.3021.7 1977271001 1977271025.6019.4 1977272016 1977272028.3020.6 1977273001 1977273027.8020.6 1977274001 1977274028.3021.7 1977275027 1977275026.7021.1 1977276000 1977276026.7019.4 1977277004 1977277028.9020.0 1977278010 1977278029.4021.1 1977279064 1977279028.3022.8 1977280000 1977280027.2020.6 1977281000 1977281028.9021.7 1977282010 1977282028.3022.2 1977283037 1977283028.3021.7 1977284004 1977284026.1019.4 1977285000 1977285027.2020.6 1977286000 1977286030.6021.1 1977287000 1977287028.9022.2 1977288000 1977288028.3022.8 1977289000 1977289028.3019.4 1977290001 1977290028.9021.1 1977291006 1977291027.8021.7 1977292000 1977292029.4025.6 1977293010 1977293028.3021.7 1977294000 1977294030.0022.2 1977295000 1977295029.4021.1 1977296000 1977296030.0021.1 1977297000 1977297030.0022.2 1977298000 1977298030.0022.2 1977299000 1977299029.4022.8 1977300000 1977300030.0019.4 1977301000 1977301030.6020.6 1977302000 1977302030.0020.0 1977303000 1977303030.6021.7 1977304000 1977304031.1021.1 1977305000 1977305030.6018.9 1977306000 1977306030.6017.8 1977307000 1977307031.7017.2 1977308000 1977308031.1017.2 1977309000 1977309031.7017.8 1977310000 1977310032.2017.2 1977311000 1977311031.7016.1 1977312000 1977312032.2016.7

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1977313000 1977313032.2020.0 1977314000 1977314031.7021.1 1977315000 1977315031.7022.8 1977316000 1977316031.7018.3 1977317000 1977317031.1020.0 1977318000 1977318031.1019.4 1977319000 1977319032.2021.1 1977320000 1977320033.3018.9 1977321000 1977321032.8022.8 1977322000 1977322032.8022.2 1977323000 1977323033.3023.3 1977324000 1977324032.2021.1 1977325000 1977325031.7021.1 1977326000 1977326031.7021.7 1977327000 1977327032.2020.6 1977328000 1977328032.2023.3 1977329000 1977329032.8022.2 1977330000 1977330032.2023.3 1977331000 1977331032.8023.3 1977332000 1977332032.8022.2 1977333000 1977333032.8020.6 1977334000 1977334031.7022.8 1977335000 1977335031.1022.8 1977336000 1977336032.2021.1 1977337000 1977337031.7021.7 1977338000 1977338028.3022.8 1977339000 1977339031.1019.4 1977340000 1977340031.7021.7 1977341000 1977341031.7022.2 1977342000 1977342032.2020.6 1977343000 1977343031.1020.6 1977344000 1977344031.1021.7 1977345000 1977345031.1022.2 1977346014 1977346030.0021.1 1977347000 1977347030.0022.2 1977348000 1977348030.6015.6 1977349000 1977349030.6016.7 1977350000 1977350031.1015.6 1977351000 1977351032.2015.6 1977352000 1977352031.7015.0 1977353000 1977353032.8015.6 1977354000 1977354032.2017.2 1977355000 1977355031.7017.8 1977356000 1977356031.7016.1 1977357000 1977357030.6016.1 1977358000 1977358029.4016.1 1977359000 1977359029.4016.1 1977360000 1977360029.4018.9 1977361000 1977361029.4018.9 1977362000 1977362030.0019.4 1977363000 1977363030.6018.9 1977364000 1977364031.7017.2 1977365000 1977365032.2016.7 1978001000 1978001032.2017.2

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1978002000 1978002032.2017.2 1978003000 1978003032.3017.2 1978004000 1978004032.8017.8 1978005000 1978005031.1019.4 1978006000 1978006030.6016.7 1978007000 1978007028.9017.2 1978008000 1978008032.2017.2 1978009000 1978009032.2018.9 1978010000 1978010031.1018.9 1978011000 1978011030.0019.4 1978012000 1978012029.4018.9 1978013000 1978013032.2017.8 1978014000 1978014032.8016.1 1978015000 1978015032.2018.3 1978016000 1978016034.4019.4 1978017000 1978017031.7021.1 1978018000 1978018031.7022.8 1978019000 1978019030.6023.3 1978020000 1978020032.8021.1 1978021000 1978021031.7022.2 1978022000 1978022031.1022.2 1978023000 1978023033.3022.8 1978024000 1978024033.3021.2 1978025000 1978025033.3021.1 1978026000 1978026033.3021.1 1978027000 1978027033.9022.2 1978028000 1978028033.9018.9 1978029000 1978029033.9022.2 1978030000 1978030033.3022.2 1978031000 1978031033.9022.8 1978032000 1978032033.3023.9 1978033000 1978033032.2022.8 1978034000 1978034034.4023.3 1978035000 1978035035.0023.3 1978036000 1978036034.4023.9 1978037000 1978037032.8023.3 1978038000 1978038031.1022.8 1978039000 1978039032.8021.7 1978040000 1978040032.2023.3 1978041000 1978041032.2023.3 1978042000 1978042033.9022.8 1978043000 1978043034.3022.2 1978044000 1978044033.3023.9 1978045000 1978045034.4023.9 1978046000 1978046033.3023.9 1978047013 1978047032.8024.4 1978048000 1978048034.4021.7 1978049000 1978049032.2022.8 1978050000 1978050033.9023.3 1978051000 1978051034.4022.8 1978052000 1978052035.0023.9 1978053000 1978053035.0023.3 1978054000 1978054035.0023.9 1978055000 1978055033.9023.9

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1978056000 1978056034.4024.4 1978057004 1978057034.4024.4 1978058001 1978058035.0022.8 1978059000 1978059032.8022.2 1978060000 1978060033.3022.2 1978061000 1978061032.8023.9 1978062000 1978062032.8021.7 1978063000 1978063033.9021.7 1978064000 1978064033.3023.3 1978065022 1978065033.3023.3 1978066000 1978066032.2021.7 1978067000 1978067029.4018.9 1978068000 1978068032.2021.1 1978069000 1978069032.2022.2 1978070000 1978070030.6023.3 1978071010 1978071033.9022.8 1978072000 1978072030.0023.9 1978073000 1978073031.1019.4 1978074000 1978074032.8022.8 1978075000 1978075033.3021.1 1978076000 1978076033.9021.7 1978077000 1978077034.4023.3 1978078000 1978078033.9023.3 1978079000 1978079032.8023.9 1978080000 1978080033.9023.9 1978081020 1978081033.9024.4 1978082000 1978082033.9023.9 1978083000 1978083030.6021.7 1978084000 1978084033.3023.3 1978085000 1978085033.3023.3 1978086000 1978086033.3023.3 1978087000 1978087034.4022.2 1978088000 1978088033.9023.9 1978089000 1978089034.4024.4 1978090000 1978090033.9022.8 1978091000 1978091033.3023.3 1978092000 1978092032.8023.9 1978093032 1978093033.9023.9 1978094002 1978094033.9023.9 1978095000 1978095026.1017.8 1978096008 1978096028.9019.4 1978097000 1978097028.9022.8 1978098000 1978098031.7021.7 1978099033 1978099031.7023.9 1978100000 1978100032.2023.9 1978101007 1978101028.3021.1 1978102000 1978102031.7022.2 1978103017 1978103031.1021.1 1978104000 1978104031.7022.8 1978105000 1978105030.0020.0 1978106005 1978106031.1021.7 1978107000 1978107031.7022.8 1978108002 1978108031.7021.1 1978109000 1978109030.0023.3

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1978110032 1978110032.2022.2 1978111020 1978111030.6023.3 1978112039 1978112027.8020.0 1978113000 1978113030.0021.7 1978114028 1978114030.0021.1 1978115000 1978115031.1022.2 1978116003 1978116030.0021.7 1978117000 1978117027.8022.2 1978118000 1978118027.8019.4 1978119017 1978119029.4020.0 1978120001 1978120029.4023.3 1978121000 1978121029.4019.4 1978122000 1978122030.0019.4 1978123000 1978123030.6020.6 1978124004 1978124031.1022.8 1978125008 1978125030.6023.3 1978126000 1978126030.0020.6 1978127000 1978127027.8019.4 1978128000 1978128030.0022.2 1978129019 1978129030.0021.1 1978130001 1978130031.1022.8 1978131000 1978131029.4020.0 1978132100 1978132030.0021.7 1978133019 1978133030.0022.8 1978134000 1978134029.4020.0 1978135000 1978135027.8019.4 1978136000 1978136031.7021.7 1978137015 1978137031.1023.9 1978138001 1978138031.1022.2 1978139000 1978139030.0021.1 1978140018 1978140031.1021.1 1978141000 1978141031.1022.8 1978142020 1978142027.2021.1 1978143000 1978143030.0021.7 1978144000 1978144029.4020.0 1978145000 1978145029.4021.7 1978146012 1978146030.6023.3 1978147009 1978147031.1023.3 1978148000 1978148030.0020.0 1978149000 1978149027.8020.0 1978150022 1978150029.4022.2 1978151117 1978151030.6023.3 1978152000 1978152028.3019.4 1978153021 1978153026.7019.4 1978154003 1978154028.9020.6 1978155000 1978155029.4020.0 1978156055 1978156028.9021.1 1978157030 1978157029.4022.2 1978158006 1978158026.7019.4 1978159000 1978159024.4020.0 1978160025 1978160029.4018.9 1978161013 1978161029.4020.6 1978162005 1978162028.3020.6 1978163000 1978163028.9020.6

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1978164000 1978164026.7018.9 1978165009 1978165030.0019.4 1978166028 1978166028.3020.6 1978167000 1978167030.0021.7 1978168000 1978168028.3018.3 1978169000 1978169027.8020.6 1978170027 1978170029.4021.7 1978171000 1978171028.9022.2 1978172000 1978172028.9020.6 1978173002 1978173030.0022.2 1978174004 1978174028.9022.2 1978175001 1978175026.7021.1 1978176001 1978176028.3021.1 1978177014 1978177028.9021.7 1978178000 1978178027.8021.1 1978179000 1978179028.9020.6 1978180000 1978180028.3021.1 1978181000 1978181027.8021.1 1978182001 1978182028.3021.1 1978183003 1978183028.3021.7 1978184000 1978184026.1021.1 1978185000 1978185026.7020.6 1978186039 1978186026.7019.4 1978187048 1978187027.8021.1 1978188002 1978188027.8020.6 1978189002 1978189028.3020.0 1978190000 1978190027.8021.1 1978191000 1978191026.1021.1 1978192000 1978192025.0020.6 1978193000 1978193026.1020.6 1978194000 1978194023.3020.0 1978195000 1978195025.6020.6 1978196000 1978196027.2021.1 1978197000 1978197027.2021.1 1978198012 1978198025.6021.1 1978199001 1978199027.2020.6 1978200000 1978200024.4020.0 1978201000 1978201025.6020.0 1978202023 1978202028.9020.0 1978203007 1978203028.9021.7 1978204000 1978204027.2021.1 1978205000 1978205028.3921.1 1978206011 1978206026.7021.1 1978207003 1978207026.7021.1 1978208000 1978208023.3020.6 1978209013 1978209025.6020.0 1978210004 1978210026.1020.0 1978211000 1978211026.7020.0 1978212000 1978212027.2020.0 1978213000 1978213027.2020.6 1978214028 1978214025.6020.6 1978215000 1978215027.8020.6 1978216001 1978216027.8020.6 1978217004 1978217026.7020.6

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1978218001 1978218028.9020.6 1978219000 1978219027.8021.1 1978220000 1978220028.3021.1 1978221000 1978221028.9021.1 1978222000 1978222028.9021.1 1978223004 1978223028.3021.1 1978224008 1978224028.3021.7 1978225001 1978225026.7021.1 1978226000 1978226023.3020.6 1978227005 1978227028.9021.1 1978228002 1978228028.9021.1 1978229002 1978229028.9021.7 1978230005 1978230028.9021.1 1978231001 1978231026.7021.1 1978232001 1978232026.1021.1 1978233027 1978233027.8021.1 1978234001 1978234024.4021.1 1978235003 1978235026.1020.6 1978236000 1978236025.0021.1 1978237003 1978237027.8021.1 1978238011 1978238028.3021.1 1978239003 1978239023.9021.1 1978240000 1978240025.6020.6 1978241000 1978241028.3020.6 1978242011 1978242027.8020.0 1978243058 1978243027.8021.1 1978244006 1978244027.2020.6 1978245001 1978245025.6019.4 1978246030 1978246028.3020.6 1978247004 1978247023.3021.1 1978248047 1978248028.9021.7 1978249000 1978249026.7019.4 1978250000 1978250027.2020.0 1978251000 1978251026.7020.0 1978252006 1978252028.9021.1 1978253006 1978253025.6021.1 1978254014 1978254027.8021.1 1978255003 1978255028.3021.1 1978256021 1978256028.9021.1 1978257005 1978257028.3021.1 1978258000 1978258027.2020.6 1978259006 1978259027.8021.1 1978260000 1978260029.4021.1 1978261004 1978261027.8018.9 1978262010 1978262027.8020.6 1978263019 1978263027.2020.6 1978264019 1978264027.8020.6 1978265009 1978265028.3021.1 1978266001 1978266024.4021.1 1978267000 1978267027.8020.0 1978268000 1978268028.3020.6 1978269000 1978269028.3021.7 1978270000 1978270026.7021.1 1978271009 1978271029.4021.7

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1978272007 1978272029.4021.7 1978273000 1978273024.4019.4 1978274004 1978274028.9019.4 1978275000 1978275028.9021.7 1978276000 1978276027.8019.4 1978277000 1978277028.9019.4 1978278000 1978278030.0021.7 1978279033 1978279029.4022.2 1978280001 1978280029.4022.2 1978281000 1978281023.9018.9 1978282000 1978282027.2019.4 1978283002 1978283028.3021.7 1978284000 1978284030.0021.7 1978285000 1978285030.6021.1 1978286012 1978286030.6021.7 1978287008 1978287030.6022.8 1978288072 1978288030.0020.6 1978289001 1978289028.9019.4 1978290000 1978290026.7020.0 1978291002 1978291027.2020.6 1978292000 1978292028.9021.1 1978293002 1978293029.4021.7 1978294000 1978294029.4021.7 1978295000 1978295029.4021.7 1978296000 1978296030.0020.0 1978297000 1978297029.4021.7 1978298002 1978298030.6021.1 1978299077 1978299028.3020.6 1978300003 1978300030.6021.1 1978301005 1978301028.9019.4 1978302000 1978302026.7021.1 1978303000 1978303026.5020.2 1978304000 1978304027.2019.4 1978305000 1978305029.4020.0 1978306019 1978306030.6022.2 1978307000 1978307030.6021.1 1978308000 1978308029.4019.4 1978309006 1978309030.0022.8 1978310002 1978310028.9021.7 1978311000 1978311028.9022.2 1978312000 1978312027.8022.2 1978313000 1978313027.8022.2 1978314012 1978314029.4022.2 1978315000 1978315028.9020.6 1978316000 1978316029.4021.1 1978317000 1978317030.0021.7 1978318000 1978318030.6019.4 1978319000 1978319030.6016.7 1978320000 1978320031.1017.2 1978321000 1978321031.1018.9 1978322000 1978322030.6016.7 1978323000 1978323031.1015.6 1978324000 1978324031.1017.2 1978325000 1978325030.6017.8

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1978326000 1978326031.1016.1 1978327000 1978327030.6016.1 1978328000 1978328031.1017.2 1978329000 1978329031.1016.1 1978330000 1978330030.6016.1 1978331000 1978331029.4017.2 1978332000 1978332030.6016.1 1978333000 1978333031.1016.1 1978334000 1978334032.2017.8 1978335000 1978335031.1021.7 1978336000 1978336032.8021.1 1978337000 1978337032.8022.2 1978338000 1978338032.2020.0 1978339000 1978339032.2019.4 1978340000 1978340031.7020.0 1978341000 1978341031.1022.2 1978342000 1978342031.7021.1 1978343000 1978343031.7021.7 1978344000 1978344031.1026.1 1978345000 1978345031.7018.9 1978346000 1978346030.0020.6 1978347000 1978347030.0019.4 1978348000 1978348030.0018.9 1978349000 1978349031.1016.1 1978350000 1978350030.6018.3 1978351000 1978351031.1016.7 1978352000 1978352031.1016.1 1978353000 1978353031.1015.0 1978354000 1978354031.7014.4 1978355000 1978355030.6017.2 1978356000 1978356030.1018.9 1978357000 1978357032.2020.0 1978358000 1978358031.7020.0 1978359000 1978359031.7022.8 1978360006 1978360032.8022.8 1978361000 1978361031.1021.7 1978362000 1978362031.7022.2 1978363000 1978363032.2021.1 1978364000 1978364031.1022.2 1978365000 1978365032.2021.7 1979001000 1979001031.7016.7 1979002000 1979002032.8015.0 1979003000 1979003031.1016.7 1979004000 1979004030.6016.7 1979005000 1979005031.7016.1 1979006000 1979006031.7016.7 1979007000 1979007032.8016.7 1979008000 1979008032.8018.9 1979009000 1979009033.3020.0 1979010000 1979010033.3020.0 1979011000 1979011032.8023.3 1979012000 1979012031.7023.3 1979013000 1979013032.8019.4 1979014000 1979014033.3022.2

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1980298000 1980298028.9020.6 1980299000 1980299028.9022.2 1980300008 1980300031.1021.7 1980301003 1980301030.0019.4 1980302000 1980302031.1021.1 1980303053 1980303028.9020.6 1980304000 1980304029.4018.9 1980305000 1980305030.4021.7 1980306000 1980306030.6022.8 1980307000 1980307029.4022.2 1980308000 1980308030.0022.2 1980309000 1980309031.7021.1 1980310000 1980310030.6022.2 1980311000 1980311031.1022.8 1980312001 1980312028.9022.8 1980313000 1980313028.3022.2 1980314000 1980314028.9022.2 1980315000 1980315030.6022.2 1980316000 1980316031.1018.3 1980317000 1980317031.1022.2 1980318000 1980318030.0021.7 1980319001 1980319029.4022.2 1980320000 1980320030.0021.1 1980321000 1980321030.6022.2 1980322016 1980322031.1022.8 1980323009 1980323030.0020.0 1980324000 1980324028.9020.6 1980325000 1980325029.4021.7 1980326000 1980326029.4020.0 1980327000 1980327030.6022.2 1980328000 1980328030.6022.2 1980329000 1980329030.6016.1 1980330000 1980330028.9017.8 1980331000 1980331027.2017.2 1980332000 1980332030.6017.8 1980333000 1980333031.1017.2 1980334000 1980334031.1018.9 1980335000 1980335031.1019.4 1980336000 1980336030.6021.7 1980337000 1980337031.1022.2 1980338000 1980338031.1022.8 1980339000 1980339031.1023.3 1980340000 1980340032.2023.3 1980341000 1980341032.2022.8 1980342000 1980342031.7021.7 1980343000 1980343031.1019.4 1980344000 1980344031.1018.9 1980345000 1980345031.1021.7 1980346000 1980346031.1020.6 1980347000 1980347027.8020.0 1980348000 1980348027.2020.6 1980349000 1980349027.8018.9 1980350000 1980350029.4018.9 1980351000 1980351030.0018.3

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1981202010 1981202023.5019.5 1981203001 1981203025.5019.5

1981204-99.0 1981204025.5021.0 1981205015 1981205026.5021.0 1981206033 1981206024.5019.5 1981207002 1981207024.5020.0

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1982053009 1982053033.0024.5 1982054004 1982054030.1022.6 1982055000 1982055030.8021.0 1982056011 1982056032.8022.5 1982057000 1982057027.4021.0 1982058000 1982058031.4021.4 1982059032 1982059031.0023.1 1982060023 1982060032.0022.0 1982061001 1982061031.5019.5 1982062000 1982062030.6020.6 1982063000 1982063033.0020.6 1982064000 1982064033.0018.3 1982065000 1982065033.0020.0 1982066000 1982066033.2020.5 1982067000 1982067033.8023.0 1982068000 1982068035.1022.1 1982069000 1982069033.8023.5 1982070001 1982070032.0024.0 1982071000 1982071030.1023.0 1982072000 1982072031.1022.5 1982073000 1982073032.0023.2 1982074000 1982074033.5021.5 1982075003 1982075030.5022.7 1982076000 1982076031.5020.5 1982077000 1982077031.0023.0 1982078000 1982078027.0021.5 1982079000 1982079032.6019.5 1982080020 1982080032.6022.5 1982081000 1982081030.8020.0 1982082000 1982082031.5022.6 1982083000 1982083029.5021.5 1982084000 1982084031.1020.0 1982085000 1982085032.3023.0 1982086000 1982086031.9022.0 1982087000 1982087031.0023.2 1982088009 1982088031.3023.4 1982089000 1982089031.0022.5 1982090000 1982090032.0022.0 1982091000 1982091032.6022.0 1982092000 1982092033.3023.5 1982093000 1982093032.5023.0 1982094000 1982094033.6023.5 1982095000 1982095033.8023.6 1982096000 1982096033.1020.0 1982097000 1982097033.0023.6 1982098026 1982098033.0023.0 1982099000 1982099032.0019.5 1982100000 1982100031.7022.1 1982101009 1982101030.0022.5 1982102000 1982102030.6020.5 1982103000 1982103031.0022.6 1982104000 1982104031.0023.0 1982105000 1982105030.5022.0 1982106007 1982106032.0023.5

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1982107000 1982107030.5020.5 1982108000 1982108031.2020.5 1982109000 1982109032.6022.5 1982110002 1982110032.0023.0 1982111000 1982111031.7023.2 1982112003 1982112031.4020.5 1982113000 1982113031.5022.5 1982114000 1982114033.0020.0 1982115000 1982115032.0022.5 1982116005 1982116033.0022.0 1982117000 1982117029.5019.5 1982118000 1982118029.8021.5 1982119013 1982119032.0022.3 1982120018 1982120028.5021.4 1982121005 1982121028.0019.5 1982122014 1982122030.0021.0 1982123000 1982123027.0020.0 1982124000 1982124029.3020.6 1982125009 1982125030.2021.8 1982126000 1982126027.7019.0 1982127000 1982127030.5020.0 1982128042 1982128029.2022.0 1982129000 1982129028.5019.0 1982130003 1982130030.2021.0 1982131000 1982131031.0022.0 1982132000 1982132031.0021.6 1982133000 1982133030.0022.5 1982134014 1982134030.5022.0 1982135000 1982135028.5019.5 1982136012 1982136030.3020.5 1982137000 1982137031.0021.0 1982138006 1982138031.0021.7 1982139027 1982139029.0018.5 1982140000 1982140027.0017.8 1982141000 1982141029.3019.2 1982142000 1982142030.0021.0 1982143011 1982143029.3021.7 1982144000 1982144028.5019.6 1982145000 1982145029.8019.5 1982146040 1982146029.5021.5 1982147006 1982147029.0018.5 1982148000 1982148031.0019.5 1982149028 1982149030.0022.0 1982150000 1982150029.3019.5 1982151000 1982151029.5021.1 1982152041 1982152025.9021.1 1982153034 1982153028.0017.0 1982154045 1982154028.2018.6 1982155000 1982155028.8018.8 1982156000 1982156028.5020.2 1982157000 1982157030.5020.5 1982158000 1982158029.3020.5 1982159000 1982159029.6021.0 1982160022 1982160029.0020.5

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1982161000 1982161027.0017.0 1982162000 1982162028.6018.0 1982163000 1982163028.5020.4 1982164000 1982164029.2020.0 1982165000 1982165028.4020.5 1982166001 1982166029.0020.3 1982167000 1982167028.5020.2 1982168001 1982168029.7021.0 1982169029 1982169026.7020.5 1982170000 1982170027.6017.5 1982171000 1982171028.0020.1 1982172000 1982172027.0020.0 1982173000 1982173026.0020.4 1982174009 1982174029.8020.0 1982175015 1982175029.0020.5 1982176009 1982176029.0019.0 1982177020 1982177027.5018.5 1982178000 1982178025.5018.5 1982179000 1982179027.4018.5 1982180000 1982180029.2020.2 1982181000 1982181029.2019.8 1982182007 1982182029.0020.3 1982183000 1982183027.5018.4 1982184001 1982184028.3020.0 1982185029 1982185028.8020.0 1982186001 1982186026.5018.0 1982187027 1982187027.0018.0 1982188003 1982188025.0017.0 1982189000 1982189027.2018.0 1982190000 1982190028.5020.0 1982191037 1982191026.0020.5 1982192005 1982192027.0018.5 1982193021 1982193027.6019.7 1982194027 1982194027.8018.3 1982195003 1982195027.7017.3 1982196001 1982196028.1020.0 1982197053 1982197025.0020.0 1982198000 1982198027.5018.5 1982199000 1982199027.5019.0 1982200041 1982200027.8019.5 1982201000 1982201028.0019.5 1982202000 1982202026.8019.5 1982203006 1982203025.5020.0 1982204001 1982204024.0018.5 1982205002 1982205025.3018.0 1982206001 1982206024.5018.5 1982207000 1982207026.5019.0 1982208031 1982208025.5019.0 1982209000 1982209028.5019.0

1982210-99.0 1982210027.8019.8 1982211000 1982211027.4019.0 1982212015 1982212026.0018.5

1982213-99.0 1982213024.0019.0 1982214001 1982214026.5019.0

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1982215000 1982215027.5019.0 1982216000 1982216026.5019.0 1982217003 1982217026.0019.0

1982218-99.0 1982218026.0019.1 1982219-99.0 1982219026.5018.5

1982220005 1982220025.5019.0 1982221001 1982221025.3018.6 1982222003 1982222026.8018.9 1982223000 1982223026.0018.6 1982224000 1982224027.6019.5 1982225054 1982225025.2019.0 1982226006 1982226025.5019.0 1982227000 1982227027.5019.0 1982228003 1982228027.5019.0 1982229022 1982229026.5018.0 1982230001 1982230025.5019.5

1982231-99.0 1982231026.0019.0 1982232000 1982232026.0019.0 1982233000 1982233025.3019.0 1982234000 1982234027.5019.5 1982235000 1982235026.0019.7 1982236015 1982236026.2019.5 1982237028 1982237027.5019.0 1982238006 1982238026.0019.1

1982239-99.0 1982239026.2019.5 1982240005 1982240028.4019.5 1982241012 1982241027.6019.5 1982242004 1982242027.0019.6 1982243013 1982243028.0020.1 1982244000 1982244026.5018.0 1982245007 1982245027.0019.0 1982246004 1982246029.0020.0 1982247005 1982247029.0019.5 1982248010 1982248027.0020.0 1982249030 1982249027.3019.0 1982250001 1982250028.0019.5 1982251019 1982251027.4019.3 1982252006 1982252025.0018.0 1982253000 1982253027.2018.4 1982254044 1982254027.5019.2

1982255-99.0 1982255028.0018.0 1982256001 1982256027.0018.0 1982257002 1982257027.5022.0 1982258012 1982258025.2018.5 1982259000 1982259029.0018.5 1982260000 1982260028.5019.5 1982261026 1982261028.0019.5

1982262-99.0 1982262024.0018.0 1982263000 1982263027.5018.0 1982264000 1982264028.6020.0 1982265013 1982265029.0019.5 1982266000 1982266025.5018.6 1982267009 1982267026.4020.0 1982268000 1982268027.0016.5

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1982269000 1982269028.0017.5 1982270001 1982270028.0020.0 1982271000 1982271028.0018.1 1982272037 1982272027.0020.0 1982273003 1982273025.0018.0 1982274017 1982274027.5018.8 1982275005 1982275028.0019.5 1982276027 1982276028.0017.0 1982277046 1982277027.5019.6 1982278001 1982278028.8018.0 1982279023 1982279026.8019.3 1982280009 1982280028.5018.8 1982281007 1982281031.4018.2 1982282058 1982282028.8018.0 1982283022 1982283026.5018.8 1982284000 1982284028.2019.0 1982285000 1982285029.0019.6 1982286042 1982286028.0020.0 1982287008 1982287028.5018.0 1982288000 1982288029.0019.7 1982289000 1982289029.0020.0 1982290000 1982290027.5020.5 1982291005 1982291029.3019.5 1982292004 1982292028.6018.0 1982293000 1982293028.5018.2 1982294000 1982294028.0019.5 1982295010 1982295028.2020.0 1982296000 1982296028.1018.7 1982297007 1982297029.0019.5

1982298-99.0 1982298028.0017.0 1982299000 1982299028.4019.5 1982300007 1982300029.0019.6 1982301005 1982301029.5019.6 1982302000 1982302027.5017.5 1982303000 1982303027.0020.0 1982304000 1982304028.8020.0 1982305017 1982305027.7020.1 1982306002 1982306029.5020.0 1982307000 1982307029.5017.5 1982308000 1982308030.5019.7 1982309000 1982309030.5021.2 1982310000 1982310030.5021.0 1982311000 1982311029.5020.3 1982312000 1982312029.8021.0 1982313000 1982313030.5019.5 1982314000 1982314030.8018.7 1982315000 1982315030.7019.0 1982316000 1982316031.5019.3 1982317000 1982317030.8018.3 1982318000 1982318030.5020.8 1982319000 1982319030.4020.0 1982320000 1982320030.0020.1 1982321000 1982321031.0021.0 1982322000 1982322031.5020.5

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1982323000 1982323031.0021.0 1982324000 1982324030.2015.5 1982325000 1982325030.3015.8 1982326000 1982326029.2015.2 1982327000 1982327028.5014.5 1982328000 1982328028.8017.5 1982329000 1982329029.5016.1 1982330000 1982330030.0013.5 1982331000 1982331030.0014.0 1982332000 1982332031.0014.0 1982333000 1982333030.5016.0 1982334000 1982334032.0016.0 1982335000 1982335031.5015.8 1982336000 1982336031.5016.5 1982337000 1982337032.0016.0 1982338000 1982338032.5016.5 1982339000 1982339030.5019.5 1982340000 1982340030.2020.0 1982341000 1982341031.5021.0 1982342000 1982342031.3020.0 1982343000 1982343032.0019.5 1982344000 1982344030.7019.5 1982345000 1982345030.0019.0 1982346000 1982346031.5016.6 1982347000 1982347030.7012.8 1982348000 1982348031.3013.5 1982349000 1982349031.6014.3 1982350000 1982350031.2016.5 1982351000 1982351033.0017.5 1982352000 1982352032.5019.2 1982353000 1982353032.4021.0 1982354000 1982354033.2019.6 1982355000 1982355032.3020.0 1982356000 1982356032.0019.5 1982357000 1982357031.0018.4 1982358000 1982358030.5019.0 1982359000 1982359032.0018.0 1982360000 1982360033.0018.5 1982361000 1982361032.8020.0 1982362000 1982362031.8018.5 1982363000 1982363030.7017.0 1982364000 1982364032.0016.5 1982365000 1982365032.5019.5

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APPENDIX 5 Statistical Meteorological Data (2009) For Nsukka

JAN FEB MARCH APR MAY JUN JUL AUG SEP OCT NOV DEC TMPMX 30.8 32.8 32.8 30.9 29.2 28.4 27.1 27.3 27.1 28.1 30.3 30.6 TMPMN 19.1 22.1 22.1 21.1 21.3 21.1 20.4 20.9 20.4 20.5 20.7 18.5 TMPSTDMX 1.38 1.45 1.19 0.97 1.19 1.39 0.94 1.4 1.21 1.55 0.98 1.11 TMPSTDMN 2.81 2.33 1.34 1.42 1.37 1.27 0.73 0.59 0.65 1.34 1.8 2.37 PCPMM 0 0 38.4 134.6 254 186.6 178.4 132.7 429.6 301.3 1.8 0 PCPSTD 0 0 38.03 132.79 250.26 183.81 173.65 130.71 416.4 296.76 1.8 0 PCPSKW 0 0 3.66 2.92 1.12 1.77 1.68 1.74 1.88 1.98 5.01 0 PR_W(1) 0 0 0.11 0.36 0.47 0.39 0.5 0.62 0.63 0.5 0.03 0 PR_W(2) 0 0 0 0 0.25 0.36 0.59 0.5 0.7 0.53 0 0 PCPD 0 0 3 8 12 11 17 18 22 17 1 0 RAINHHMX 0 0 10.4 25.6 28.8 26.4 26 23.1 38.4 30.1 0.4 0 SOLARAV 13 14 14.8 14.6 12.8 11.7 9.9 9.9 11.4 12.1 15.4 14.7 REL HUM 0.43 0.51 0.61 0.69 0.73 0.76 0.8 0.81 0.81 0.79 0.65 0.41 WNDAV 42.38 51.29 56.09 52.41 43.97 44.98 46.11 52.47 45.31 41.23 41.4 49.34

TMPMX; Mean daily maximum air temperature for month (ºC) TMPMN: Mean daily minimum air temperature for month (ºC) TMPSTDMX: Standard deviation for daily maximum air temperature in month (ºC) TMPSTDMN: Standard deviation for daily minimum air temperature in month (ºC) PCPMM: Mean daily precipitation in month (mm H2O) PCPSTD: Standard deviation for daily precipitation in month (mm H2O/day) PCPSKW; Skew coefficient for daily precipitation in month PR_W(1): Probability of a wet day following a dry day in the month PR_W(2): Probability of a wet day following a wet day in the month PCPD; Average number of days of precipitation in month RAINHHMX: Maximum 0.5 hour rainfall in entire period of record for month (mm H2O) SOLARAV: Average daily solar radiation in month (MJ/m2/day) REL HUM: Relative humidity WNDAV: Average daily wind speed in month (m/s)

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APPENDIX 6 SCENARIO 0 - CONTROL RUN

Sample Output of HRU Distribution Number of HRUs: 96 Number of subbasins: 29 --------------------------------------------------------------------------- Area [ha] Watershed 376464.47 --------------------------------------------------------------------------- Area (ha) Watershed (%) Landuse SAVA 353331.05 93.86 CRWO 3117.14 0.83 FOEB 163.48 0.04 CRDY 19481.82 5.17 URMD 370.98 0.10 Soil Nd5-1a-1567 21739.48 5.77 Nd16-2-3a-1553 341927.88 90.83 Ap15-1a-1068 10715.96 2.85 Gd16-2-3a-1201 2081.15 0.55 Slope 0-5 315377.78 83.77 5-67 61086.69 16.23 ---------------------------------------------------------------------------

Area [ha] Watershed(%) Subbasin(%) Subbasin 1 16643.64 4.42 Landuse SAVA 13923.77 3.70 83.66 CRDY 2634.32 0.70 15.83 FOEB 85.55 0.02 0.51 Soil Nd16-2-3a-1553 16643.64 4.42 100.00 Slope 0-5 14944.46 3.97 89.79 5-67 1699.18 0.45 10.21 HRUs: 1 SAVA/Nd16-2-3a-1553/5-67 1415.42 0.38 8.50 2 SAVA/Nd16-2-3a-1553/0-5 12508.35 3.32 75.15 3 FOEB/Nd16-2-3a-1553/5-67 8.47 0.00 0.05 4 FOEB/Nd16-2-3a-1553/0-5 77.08 0.02 0.46 5 CRDY/Nd16-2-3a-1553/5-67 275.29 0.07 1.65 6 CRDY/Nd16-2-3a-1553/0-5 2359.03 0.63 14.17 ---------------------------------------------------------------------------

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Area(ha) Watershed(%) Subbasin(%) Subbasin 2 24706.69 6.56 Landuse SAVA 22920.26 6.09 92.77 CRDY 1415.45 0.38 5.73 URMD 370.98 0.10 1.50 Soil Nd16-2-3a-1553 15964.35 4.24 64.62 Ap15-1a-1068 8742.34 2.32 35.38 Slope 0-5 18975.54 5.04 76.80 5-67 5731.15 1.52 23.20 HRUs: 7 SAVA/Nd16-2-3a-1553/5-67 2367.18 0.63 9.58 8 SAVA/Nd16-2-3a-1553/0-5 12181.72 3.24 49.31 9 SAVA/Ap15-1a-1068/5-67 2985.19 0.79 12.08 10 SAVA/Ap15-1a-1068/0-5 5386.17 1.43 21.80 11 CRDY/Nd16-2-3a-1553/5-67 183.76 0.05 0.74 12 CRDY/Nd16-2-3a-1553/0-5 1231.69 0.33 4.99 13 URMD/Ap15-1a-1068/5-67 195.03 0.05 0.79 14 URMD/Ap15-1a-1068/0-5 175.96 0.05 0.71 --------------------------------------------------------------------------- Area [ha] Watershed(%) Subbasin(%) Subbasin 3 16172.68 4.30 Landuse SAVA 16172.68 4.30 100.00 Soil Nd16-2-3a-1553 16172.68 4.30 100.00 Slope 0-5 13306.27 3.53 82.28 5-67 2866.41 0.76 17.72 HRUs: 15 SAVA/Nd16-2-3a-1553/5-67 2866.41 0.76 17.72 16 SAVA/Nd16-2-3a-1553/0-5 13306.27 3.53 82.28 ---------------------------------------------------------------------------

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APPENDIX 7 Scenario 1

Sample Output of HRU Distribution Number of HRUs: 164 Number of subbasins: 29 --------------------------------------------------------------------------- Area [ha] Watershed 376464.47 --------------------------------------------------------------------------- Area [ha] %Watershed Landuse GRAS 352977.72 93.76 CRWO 3117.14 0.83 CRDY 19481.82 5.17 AGRR 353.33 0.09 FOEB 163.48 0.04 URMD 370.98 0.10 Soil Nd5-1a-1567 21739.48 5.77 Nd16-2-3a-1553 341927.88 90.83 Ap15-1a-1068 10715.96 2.85 Gd16-2-3a-1201 2081.15 0.55 Slope 0-5 315377.78 83.77 5-67 61086.69 16.23 --------------------------------------------------------------------------- --------------------------------------------------------------------------- Area [ha] Watershed(%) Subbasin(%) Subbasin 1 16643.64 4.42 Landuse GRAS 13909.85 3.69 83.57 FOEB 85.55 0.02 0.51 AGRR 13.92 0.00 0.08 CRDY 2634.32 0.70 15.83 Soil Nd16-2-3a-1553 16643.64 4.42 100.00 Slope 0-5 14944.46 3.97 89.79 5-67 1699.18 0.45 10.21

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HRUs: 1 GRAS/Nd16-2-3a-1553/5-67 1414.00 0.38 8.50 2 GRAS/Nd16-2-3a-1553/0-5 12495.85 3.32 75.08 3 CRDY/Nd16-2-3a-1553/5-67 275.29 0.07 1.65 4 CRDY/Nd16-2-3a-1553/0-5 2359.03 0.63 14.17 5 AGRR/Nd16-2-3a-1553/5-67 1.42 0.00 0.01 6 AGRR/Nd16-2-3a-1553/0-5 12.51 0.00 0.08 7 FOEB/Nd16-2-3a-1553/5-67 8.47 0.00 0.05 8 FOEB/Nd16-2-3a-1553/0-5 77.08 0.02 0.46 --------------------------------------------------------------------------- Area [ha] Watershed(%) Subbasin(%) Subbasin 2 24706.69 6.56 Landuse GRAS 22897.34 6.08 92.68 AGRR 22.92 0.01 0.09 CRDY 1415.45 0.38 5.73 URMD 370.98 0.10 1.50 Soil Nd16-2-3a-1553 15964.35 4.24 64.62 Ap15-1a-1068 8742.34 2.32 35.38 Slope 0-5 18975.54 5.04 76.80 5-67 5731.15 1.52 23.20 HRUs: 9 GRAS/Nd16-2-3a-1553/5-67 2364.81 0.63 9.57 10 GRAS/Nd16-2-3a-1553/0-5 12169.54 3.23 49.26 11 GRAS/Ap15-1a-1068/5-67 2982.20 0.79 12.07 12 GRAS/Ap15-1a-1068/0-5 5380.78 1.43 21.78 13 AGRR/Nd16-2-3a-1553/5-67 2.37 0.00 0.01 14 AGRR/Nd16-2-3a-1553/0-5 12.18 0.00 0.05 15 AGRR/Ap15-1a-1068/5-67 2.99 0.00 0.01 16 AGRR/Ap15-1a-1068/0-5 5.39 0.00 0.02 17 CRDY/Nd16-2-3a-1553/5-67 183.76 0.05 0.74 18 CRDY/Nd16-2-3a-1553/0-5 1231.69 0.33 4.99 19 URMD/Ap15-1a-1068/5-67 195.03 0.05 0.79 20 URMD/Ap15-1a-1068/0-5 175.96 0.05 0.71 ---------------------------------------------------------------------------

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APPENDIX 8 Scenario 2

Sample Output of HRU Distribution Number of HRUs: 164 Number of subbasins: 29 --------------------------------------------------------------------------- Area [ha] Watershed 376464.47 --------------------------------------------------------------------------- Area [ha] Watershed(%) Landuse GRAS 282664.84 75.08 CRWO 3117.14 0.83 CRDY 19481.82 5.17 AGRR 70666.21 18.77 FOEB 163.48 0.04 URMD 370.98 0.10 Soil Nd5-1a-1567 21739.48 5.77 Nd16-2-3a-1553 341927.88 90.83 Ap15-1a-1068 10715.96 2.85 Gd16-2-3a-1201 2081.15 0.55 Slope 0-5 315377.78 83.77 5-67 61086.69 16.23 --------------------------------------------------------------------------- --------------------------------------------------------------------------- Area [ha] Watershed(%) Subbasin(%) Subbasin 1 16643.64 4.42 Landuse GRAS 11139.02 2.96 66.93 FOEB 85.55 0.02 0.51 AGRR 2784.75 0.74 16.73 CRDY 2634.32 0.70 15.83 Soil Nd16-2-3a-1553 16643.64 4.42 100.00 Slope 0-5 14944.46 3.97 89.79 5-67 1699.18 0.45 10.21 HRUs:

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1 GRAS/Nd16-2-3a-1553/5-67 1132.33 0.30 6.80 2 GRAS/Nd16-2-3a-1553/0-5 10006.68 2.66 60.12 3 CRDY/Nd16-2-3a-1553/5-67 275.29 0.07 1.65 4 CRDY/Nd16-2-3a-1553/0-5 2359.03 0.63 14.17 5 AGRR/Nd16-2-3a-1553/5-67 283.08 0.08 1.70 6 AGRR/Nd16-2-3a-1553/0-5 2501.67 0.66 15.03 7 FOEB/Nd16-2-3a-1553/5-67 8.47 0.00 0.05 8 FOEB/Nd16-2-3a-1553/0-5 77.08 0.02 0.46 --------------------------------------------------------------------------- Area [ha] Watershed(%) Subbasin(%) Subbasin 2 24706.69 6.56 Landuse GRAS 18336.21 4.87 74.22 AGRR 4584.05 1.22 18.55 CRDY 1415.45 0.38 5.73 URMD 370.98 0.10 1.50 Soil Nd16-2-3a-1553 15964.35 4.24 64.62 Ap15-1a-1068 8742.34 2.32 35.38 Slope 0-5 18975.54 5.04 76.80 5-67 5731.15 1.52 23.20 HRUs: 9 GRAS/Nd16-2-3a-1553/5-67 1893.74 0.50 7.66 10 GRAS/Nd16-2-3a-1553/0-5 9745.38 2.59 39.44 11 GRAS/Ap15-1a-1068/5-67 2388.15 0.63 9.67 12 GRAS/Ap15-1a-1068/0-5 4308.94 1.14 17.44 13 AGRR/Nd16-2-3a-1553/5-67 473.44 0.13 1.92 14 AGRR/Nd16-2-3a-1553/0-5 2436.34 0.65 9.86 15 AGRR/Ap15-1a-1068/5-67 597.04 0.16 2.42 16 AGRR/Ap15-1a-1068/0-5 1077.23 0.29 4.36 17 CRDY/Nd16-2-3a-1553/5-67 183.76 0.05 0.74 18 CRDY/Nd16-2-3a-1553/0-5 1231.69 0.33 4.99 19 URMD/Ap15-1a-1068/5-67 195.03 0.05 0.79 20 URMD/Ap15-1a-1068/0-5 175.96 0.05 0.71 ----------------------------------------------- ----------------------------

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APPENDIX 9 Scenario 3

Sample Output of HRU Distribution Number of HRUs: 164 Number of subbasins: 29 --------------------------------------------------------------------------- Area [ha] Watershed 376464.47 --------------------------------------------------------------------------- Area [ha] Watershed(%) Landuse GRAS 211998.63 56.31 CRWO 3117.14 0.83 CRDY 19481.82 5.17 AGRR 141332.42 37.54 FOEB 163.48 0.04 URMD 370.98 0.10 Soil Nd5-1a-1567 21739.48 5.77 Nd16-2-3a-1553 341927.88 90.83 Ap15-1a-1068 10715.96 2.85 Gd16-2-3a-1201 2081.15 0.55 Slope 0-5 315377.78 83.77 5-67 61086.69 16.23 --------------------------------------------------------------------------- --------------------------------------------------------------------------- Area [ha] Watershed(%) Subbasin(%) Subbasin 1 16643.64 4.42 Landuse GRAS 8354.26 2.22 50.19 FOEB 85.55 0.02 0.51 AGRR 5569.51 1.48 33.46 CRDY 2634.32 0.70 15.83 Soil Nd16-2-3a-1553 16643.64 4.42 100.00 Slope 0-5 14944.46 3.97 89.79 5-67 1699.18 0.45 10.21 HRUs:

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1 GRAS/Nd16-2-3a-1553/5-67 849.25 0.23 5.10 2 GRAS/Nd16-2-3a-1553/0-5 7505.01 1.99 45.09 3 CRDY/Nd16-2-3a-1553/5-67 275.29 0.07 1.65 4 CRDY/Nd16-2-3a-1553/0-5 2359.03 0.63 14.17 5 AGRR/Nd16-2-3a-1553/5-67 566.17 0.15 3.40 6 AGRR/Nd16-2-3a-1553/0-5 5003.34 1.33 30.06 7 FOEB/Nd16-2-3a-1553/5-67 8.47 0.00 0.05 8 FOEB/Nd16-2-3a-1553/0-5 77.08 0.02 0.46 --------------------------------------------------------------------------- Area [ha] Watershed%) Subbasin%) Subbasin 2 24706.69 6.56 Landuse GRAS 13752.15 3.65 55.66 AGRR 9168.10 2.44 37.11 CRDY 1415.45 0.38 5.73 URMD 370.98 0.10 1.50 Soil Nd16-2-3a-1553 15964.35 4.24 64.62 Ap15-1a-1068 8742.34 2.32 35.38 Slope 0-5 18975.54 5.04 76.80 5-67 5731.15 1.52 23.20 HRUs: 9 GRAS/Nd16-2-3a-1553/5-67 1420.31 0.38 5.75 10 GRAS/Nd16-2-3a-1553/0-5 7309.03 1.94 29.58 11 GRAS/Ap15-1a-1068/5-67 1791.11 0.48 7.25 12 GRAS/Ap15-1a-1068/0-5 3231.70 0.86 13.08 13 AGRR/Nd16-2-3a-1553/5-67 946.87 0.25 3.83 14 AGRR/Nd16-2-3a-1553/0-5 4872.69 1.29 19.72 15 AGRR/Ap15-1a-1068/5-67 1194.08 0.32 4.83 16 AGRR/Ap15-1a-1068/0-5 2154.47 0.57 8.72 17 CRDY/Nd16-2-3a-1553/5-67 183.76 0.05 0.74 18 CRDY/Nd16-2-3a-1553/0-5 1231.69 0.33 4.99 19 URMD/Ap15-1a-1068/5-67 195.03 0.05 0.79 20 URMD/Ap15-1a-1068/0-5 175.96 0.05 0.71 ---------------------------------------------------------------------------

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APPENDIX 10 Scenario 4

Sample Output of HRU Distribution Number of HRUs: 164 Number of subbasins: 29 Landuses exempt from thresholds: FOEB URMD --------------------------------------------------------------------------- Area [ha] Watershed 376464.47 --------------------------------------------------------------------------- Area [ha] Watershed(%) Landuse GRAS 141332.42 37.54 CRWO 3117.14 0.83 CRDY 19481.82 5.17 AGRR 211998.63 56.31 FOEB 163.48 0.04 URMD 370.98 0.10 Soil Nd5-1a-1567 21739.48 5.77 Nd16-2-3a-1553 341927.88 90.83 Ap15-1a-1068 10715.96 2.85 Gd16-2-3a-1201 2081.15 0.55 Slope 0-5 315377.78 83.77 5-67 61086.69 16.23 --------------------------------------------------------------------------- --------------------------------------------------------------------------- Area [ha] Watershed(%) Subbasin(%) Subbasin 1 16643.64 4.42 Landuse GRAS 5569.51 1.48 33.46 FOEB 85.55 0.02 0.51 AGRR 8354.26 2.22 50.19 CRDY 2634.32 0.70 15.83 Soil Nd16-2-3a-1553 16643.64 4.42 100.00 Slope 0-5 14944.46 3.97 89.79 5-67 1699.18 0.45 10.21 HRUs:

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1 GRAS/Nd16-2-3a-1553/5-67 566.17 0.15 3.40 2 GRAS/Nd16-2-3a-1553/0-5 5003.34 1.33 30.06 3 CRDY/Nd16-2-3a-1553/5-67 275.29 0.07 1.65 4 CRDY/Nd16-2-3a-1553/0-5 2359.03 0.63 14.17 5 AGRR/Nd16-2-3a-1553/5-67 849.25 0.23 5.10 6 AGRR/Nd16-2-3a-1553/0-5 7505.01 1.99 45.09 7 FOEB/Nd16-2-3a-1553/5-67 8.47 0.00 0.05 8 FOEB/Nd16-2-3a-1553/0-5 77.08 0.02 0.46 --------------------------------------------------------------------------- Area [ha] Watershed(%) Subbasin(%) Subbasin 2 24706.69 6.56 Landuse GRAS 9168.10 2.44 37.11 AGRR 13752.15 3.65 55.66 CRDY 1415.45 0.38 5.73 URMD 370.98 0.10 1.50 Soil Nd16-2-3a-1553 15964.35 4.24 64.62 Ap15-1a-1068 8742.34 2.32 35.38 Slope 0-5 18975.54 5.04 76.80 5-67 5731.15 1.52 23.20 HRUs: 9 GRAS/Nd16-2-3a-1553/5-67 946.87 0.25 3.83 10 GRAS/Nd16-2-3a-1553/0-5 4872.69 1.29 19.72 11 GRAS/Ap15-1a-1068/5-67 1194.08 0.32 4.83 12 GRAS/Ap15-1a-1068/0-5 2154.47 0.57 8.72 13 AGRR/Nd16-2-3a-1553/5-67 1420.31 0.38 5.75 14 AGRR/Nd16-2-3a-1553/0-5 7309.03 1.94 29.58 15 AGRR/Ap15-1a-1068/5-67 1791.11 0.48 7.25 16 AGRR/Ap15-1a-1068/0-5 3231.70 0.86 13.08 17 CRDY/Nd16-2-3a-1553/5-67 183.76 0.05 0.74 18 CRDY/Nd16-2-3a-1553/0-5 1231.69 0.33 4.99 19 URMD/Ap15-1a-1068/5-67 195.03 0.05 0.79 20 URMD/Ap15-1a-1068/0-5 175.96 0.05 0.71 ---------------------------------------------------------------------------

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APPENDIX 11 Scenario 5

Sample Output of HRU Distribution Number of HRUs: 164 Number of subbasins: 29 --------------------------------------------------------------------------- Area [ha] Watershed 376464.47 --------------------------------------------------------------------------- Area [ha] Watershed(%) Landuse GRAS 70666.21 18.77 CRWO 3117.14 0.83 CRDY 19481.82 5.17 AGRR 282664.84 75.08 FOEB 163.48 0.04 URMD 370.98 0.10 Soil Nd5-1a-1567 21739.48 5.77 Nd16-2-3a-1553 341927.88 90.83 Ap15-1a-1068 10715.96 2.85 Gd16-2-3a-1201 2081.15 0.55 Slope 0-5 315377.78 83.77 5-67 61086.69 16.23 --------------------------------------------------------------------------- --------------------------------------------------------------------------- Area [ha] Watershed(%) Subbasin(%) Subbasin 1 16643.64 4.42 Landuse GRAS 2784.75 0.74 16.73 FOEB 85.55 0.02 0.51 AGRR 11139.02 2.96 66.93 CRDY 2634.32 0.70 15.83 Soil Nd16-2-3a-1553 16643.64 4.42 100.00 Slope 0-5 14944.46 3.97 89.79 5-67 1699.18 0.45 10.21 HRUs:

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1 GRAS/Nd16-2-3a-1553/5-67 283.08 0.08 1.70 2 GRAS/Nd16-2-3a-1553/0-5 2501.67 0.66 15.03 3 CRDY/Nd16-2-3a-1553/5-67 275.29 0.07 1.65 4 CRDY/Nd16-2-3a-1553/0-5 2359.03 0.63 14.17 5 AGRR/Nd16-2-3a-1553/5-67 1132.33 0.30 6.80 6 AGRR/Nd16-2-3a-1553/0-5 10006.68 2.66 60.12 7 FOEB/Nd16-2-3a-1553/5-67 8.47 0.00 0.05 8 FOEB/Nd16-2-3a-1553/0-5 77.08 0.02 0.46 --------------------------------------------------------------------------- Area [ha] Watershed(%) Subbasin(%) Subbasin 2 24706.69 6.56 Landuse GRAS 4584.05 1.22 18.55 AGRR 18336.21 4.87 74.22 CRDY 1415.45 0.38 5.73 URMD 370.98 0.10 1.50 Soil Nd16-2-3a-1553 15964.35 4.24 64.62 Ap15-1a-1068 8742.34 2.32 35.38 Slope 0-5 18975.54 5.04 76.80 5-67 5731.15 1.52 23.20 HRUs: 9 GRAS/Nd16-2-3a-1553/5-67 473.44 0.13 1.92 10 GRAS/Nd16-2-3a-1553/0-5 2436.34 0.65 9.86 11 GRAS/Ap15-1a-1068/5-67 597.04 0.16 2.42 12 GRAS/Ap15-1a-1068/0-5 1077.23 0.29 4.36 13 AGRR/Nd16-2-3a-1553/5-67 1893.74 0.50 7.66 14 AGRR/Nd16-2-3a-1553/0-5 9745.38 2.59 39.44 15 AGRR/Ap15-1a-1068/5-67 2388.15 0.63 9.67 16 AGRR/Ap15-1a-1068/0-5 4308.94 1.14 17.44 17 CRDY/Nd16-2-3a-1553/5-67 183.76 0.05 0.74 18 CRDY/Nd16-2-3a-1553/0-5 1231.69 0.33 4.99 19 URMD/Ap15-1a-1068/5-67 195.03 0.05 0.79 20 URMD/Ap15-1a-1068/0-5 175.96 0.05 0.71 ---------------------------------------------------------------------------

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APPENDIX 12 Scenario 6

Sample Output of HRU Distribution Number of HRUs: 164 Number of subbasins: 29 --------------------------------------------------------------------------- Area [ha] Watershed 376464.47 --------------------------------------------------------------------------- Area [ha] Watershed(%) Landuse GRAS 353.33 0.09 CRWO 3117.14 0.83 CRDY 19481.82 5.17 AGRR 352977.72 93.76 FOEB 163.48 0.04 URMD 370.98 0.10 Soil Nd5-1a-1567 21739.48 5.77 Nd16-2-3a-1553 341927.88 90.83 Ap15-1a-1068 10715.96 2.85 Gd16-2-3a-1201 2081.15 0.55 Slope 0-5 315377.78 83.77 5-67 61086.69 16.23 --------------------------------------------------------------------------- --------------------------------------------------------------------------- Area [ha] Watershed(% Subbasin(% Subbasin 1 16643.64 4.42 Landuse GRAS 13.92 0.00 0.08 FOEB 85.55 0.02 0.51 AGRR 13909.85 3.69 83.57 CRDY 2634.32 0.70 15.83 Soil Nd16-2-3a-1553 16643.64 4.42 100.00 Slope 0-5 14944.46 3.97 89.79 5-67 1699.18 0.45 10.21 HRUs:

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1 GRAS/Nd16-2-3a-1553/5-67 1.42 0.00 0.01 2 GRAS/Nd16-2-3a-1553/0-5 12.51 0.00 0.08 3 CRDY/Nd16-2-3a-1553/5-67 275.29 0.07 1.65 4 CRDY/Nd16-2-3a-1553/0-5 2359.03 0.63 14.17 5 AGRR/Nd16-2-3a-1553/5-67 1414.00 0.38 8.50 6 AGRR/Nd16-2-3a-1553/0-5 12495.85 3.32 75.08 7 FOEB/Nd16-2-3a-1553/5-67 8.47 0.00 0.05 8 FOEB/Nd16-2-3a-1553/0-5 77.08 0.02 0.46 --------------------------------------------------------------------------- Area [ha] Watershed(% Subbasin(% Subbasin 2 24706.69 6.56 Landuse GRAS 22.92 0.01 0.09 AGRR 22897.34 6.08 92.68 CRDY 1415.45 0.38 5.73 URMD 370.98 0.10 1.50 Soil Nd16-2-3a-1553 15964.35 4.24 64.62 Ap15-1a-1068 8742.34 2.32 35.38 Slope 0-5 18975.54 5.04 76.80 5-67 5731.15 1.52 23.20 HRUs: 9 GRAS/Nd16-2-3a-1553/5-67 2.37 0.00 0.01 10 GRAS/Nd16-2-3a-1553/0-5 12.18 0.00 0.05 11 GRAS/Ap15-1a-1068/5-67 2.99 0.00 0.01 12 GRAS/Ap15-1a-1068/0-5 5.39 0.00 0.02 13 AGRR/Nd16-2-3a-1553/5-67 2364.81 0.63 9.57 14 AGRR/Nd16-2-3a-1553/0-5 12169.54 3.23 49.26 15 AGRR/Ap15-1a-1068/5-67 2982.20 0.79 12.07 16 AGRR/Ap15-1a-1068/0-5 5380.78 1.43 21.78 17 CRDY/Nd16-2-3a-1553/5-67 183.76 0.05 0.74 18 CRDY/Nd16-2-3a-1553/0-5 1231.69 0.33 4.99 19 URMD/Ap15-1a-1068/5-67 195.03 0.05 0.79 20 URMD/Ap15-1a-1068/0-5 175.96 0.05 0.71 ---------------------------------------------------------------------------