water resources plan

7/28/2019 Water Resources Plan

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INTRODUCTION

Irrigation is an artificial application of water to the soil. It is usually used to assist in

growing crops in dry areas and during periods of inadequate rainfall. Additionally, it is

very vital in crop production especially in rain-fed farming.

The future of agriculture and food production lies much on irrigation. At the global

scale 2,788,000 square kilometers of agricultural land is equipped with irrigation

infrastructure. About 68% of the area equipped with irrigation is located in Asia, 17%

in America, 9% in Europe, 5% in Africa and 1% in Oceania. A number of dams and

irrigation infrastructure were built to increase the supply of water as well as to

maximize the use of its availability.

In the Philippines, agriculture is the lifeblood of the Filipino people. Various crops

such as rice, corn, vegetables and others are widely cultivated to meet the

increasing demand for food as the countrys population is in the boom. With this, to

elevate food self-sufficiency of the country, the government together with private

sectors joins hand in hand to provide adequate irrigation water for food production

through implementing water resources infrastructure project throughout the country.

While the Tucalan Communal Irrigation System has been in service for several

cropping seasons, its efficiency has gradually deteriorated over the years. The

increasing demand of water irrigation use has led into many constraints such as

capacity problems, insufficient water quality and the technical deficiencies of existing

irrigation infrastructures. It is in this view that the rehabilitation of the system had

been included as a priority project in order to ensure efficient delivery of irrigation

water to the farms of the existing irrigation system.

Water Resource Plan Tucalan Communal Irrigation System 1 of 39


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PROBLEMS AND CONSTRAINTS

The identified problems in the project area were related to production, technical and

social problems.

Production Problems:

The unit yield of rice in the area prior to the project was considerably low at an

average of 50 cavans per hectare. With no irrigation system, rice was grown

under rain fed conditions. During some cropping seasons, the vegetative growth

of rice was severely damaged due to lack of soil moisture. Harvest, therefore,

during these periods were below the national average.

Technical Problems:

Agricultural activities were limited in the project area for lack of adequate

irrigation water. Cultivation of rice as a major crop depended on rainfall which

resulted to very low yields. The heavily silted reservoir has led to very low water

head which was not sufficient to supply the irrigation water requirement of the

farmlands. Additionally, deteriorating intake and canal structures resulted to

inefficient water delivery and distribution to the service areas. Most of the lined

canals were cracked and silted. On the other hand, the earth canals were eroded

and required reshaping.

Social and Institutional Problem:

Non-existence of the Irrigators Association led to the insufficient knowledge of

water users on proper water management which in turn resulted to the

proliferation of illegal users, damage to canal structures and wastage of irrigation

water. With no peoples organization supervising the operation of the system,

collection rate of irrigation service fee was low and no sufficient maintenance

resources were available during maintenance period. Damage structures and

facilities were not restored and their conditions were aggravated with passing of

each cropping season.



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OBJECTIVES OF THE PROJECTThe identification of long term and short term is hoped to guide public and private

sector development decisions and activities direction. The results are expected to

support the sustainability of the projected growth intensity for the 50-year period.

The short-term and long-term objectives of the rehabilitation of the project are

presented below:

Short-Term Objectives

1. To restore the intake structures and drainage facilities of the irrigation system

in order to re-establish its functionality and operation.

2. To strengthen the Irrigators Association capacity to undertake productive

activities by providing institutional and agricultural support such as extension

services, cooperative organization and social capability building.

3. To improve the productive potentials of the agricultural farmlands in the area

through increased cropping intensity and crop diversification.

Long-Term Objectives

1. To alleviate poverty and improve well-being of the farmer beneficiaries by

giving them opportunities to increase their income.

2. To transform the Irrigators Association into a self-sufficient organization

capable of efficiently and effectively managing the operations of the system.

At full development, production from the project area is expected to increase from

2.50 tons/hectare to 5.00 tons/hectare for the first crop and 5.00 tons/ha for the

second crop. However, production cost will increase considering the introduction of

modern methods of farming with more inputs to be supplied. The target cropping

intensity will be up to 148% in the whole service area. Palay production is also

expected to reach 1,150 tons annually in the whole area from the present 387.50tons.



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EXISTING CHARACTERISTICS AND CONDITIONS OF THE STUDY AREA

A Br ie f H is to ry o f Lasam

History is by and large, the story in retrospect of a land and its people. The land, its

name and occupancy, its location and wealth, the people , their idiosyncrasies and

attributes, their tradition and culture, their faith and beliefs, their occupation andpursuits, their tribulations and ordeals, nay, their settlements and systems of

government, are history's subject matter and reasons for being.

The Land

Barrio Macatabang was a place along the bank of the Cagayan River called so

inhabited by Ybanag, Ilocano immigrant Filipino Chinese, and Malaweg.

Macatabang was a part of Gattaran, but as the population increased, the people of

the western part of Gattaran made a resolution that it be made a separate town.

Congressman Paulino Alonso of the 2nd District of Cagayan introduced a bill in

congress creating the municipality of Santo Tomas. Representative Cabarroguis of

Nueva Vizcaya vigorously objected the suggested name on the first reading of the

bill. Finally, Lasam was agreed upon in honor of the late Governor Honorio Lasam,

the sixth governor of Cagayan (1915-1918)



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On June 13, 1950, the late President Elpidio C. Quirino signed R.A. 507 which made

possible the creation of the municipality of Lasam.

January 1951 was eventful for Lasam

because it was her official inauguration as a

town. However, another problem arose after

the celebration of its inauguration. Although,

it was stated in the bill that the site of Lasam

would be the barrio be made the town site. In

order to settle the dispute, an arrangement

between the two political factions (the Jurado

faction of Macatabang and the the Acre faction of Nabannagan) was made. They

agreed that whoever was elected Mayor would have the privilege to situate the seat

of government in his respective barrio. Fortunately, Jurado was elected Mayor by a

margin of only two votes over Acre, thus, Macatabang became the town proper.

The Immigrants

In the early part of the 40s, immigrants

from other provinces came to settle in

Lasam and its nearby environs. They

came from the central plains and the

Ilocano provinces. Majority of them were

Ilocanos who brought with them

industriousness, thriftiness and sturdiness.

Settling in the plains and meadows of the

municipality, the Ilocanos with diligence who howed their lands into productive forms

which boosted no less than the economic progress of Lasam.

Eager and desirous to improve their lot, many of the immigrants have managed to

send and continue to send their children to the schools, colleges, and universities

enhancing on the process the literacy pasture of the municipality. From their ranks

have emerged many of the municipality's teachers, artisans and professionals.



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It is important to note in this connection that a number of them have become Chief

Executives of Lasam.

Lasam is considered the largest municipality of the second district of the province of

Cagayan in terms of population. It is also known as the rice bowl of Western

Cagayan. It is the nucleus of the

Zinundungan Valley and was

endowed an abundant forest

resources particularly hard umber

and mangrove species. The

municipality boosts excellent

education system where one tertiary

level, two vocational/agricultural

secondary level, three academic

high school, one TESDA institution

and complete elementary and primary schools scattered all the barangays all over

the area. The town is the second youngest town in the province.

Location and Wealth

Lasam town proper barely 13 kilometers, 20 degree south west of Magapit

Suspension Bridge. It is 68 kilometers north of Tuguegarao, Cagayan by crossing

the Cagayan River from the municipality of Gattaran, but following the Lasam-Logac-

Magapit National Road, is 106 kilometers

from Tuguegarao, Cagayan. It is bounded on

the north east by the municipality of Lallo,

Cagayan, on the north west by the

municipality of Allacapan, Cagayan and

Flora,Apayao, on the east by the Cagayan

River, and Gattaran, Cagayan, on the south

by Santo Nio, Cagayan and on the south

west by the municipality of Rizal, Cagayan.



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It must have been for its location, its agricultural and commercial potentialities that

prompted early immigrants to transfer to Lasam. Future events

proved the wisdom of their choice for, with the Cagayan River and the Zinundungan

River as the chief means of transportation at that time and for the long period, Lasam

became the hub of trade and commerce for a wide area.

The rivers were teeming with freshwater

fish and shells and forests were

everywhere abounding with raw building

materials and wildlife. In fact, venison

and meat of wild pigs were commodities

which the traders from Aparri, with their

roof-flat-bottomed rafts and boats, bough

in quantity.

Greed and ignorance soon took its toll. Forests were denuded without the thought of

the future resulting in big floods and extensive soil erosion. Fingerlings, too, were

trapped or caught for food or sale.

The saving grace from all these senseless wastes came later when with advanced

technology, a breakthrough in rice production was achieved. Farmers who would

harvest only 15 to 25 cavans per hectare could now produce 70 to 100 cavans. Corn

also became a prime crop augmenting the income of the farmers to a marked

degree.

Area and Population

Lasam has a total land area of 234 square kilometers or 23,400 hectares.

The total area of the municipality is divided among 30 barangays namely:


PINSAL FALLS


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BARANGAY POPULATION

Aggunetan 1,083

Alannay 2,022

Battalan 1,073

Cabatacan East (Duldugan) 1,799

Cabatacan West 1,606

Calapangan Norte 825

Calapangan Sur 749

Callao Norte 828

Callao Sur 840

Cataliganan 323

Centro I (Pob.) 2,259

Centro II (Pob.) 2,078

Centro III (Pob.) 1,817

Finugo Norte 520

Gabun 1,125

Ignacio Jurado (Finugu Sur) 1,573

Magsaysay 1,404

Malinta 1,070

Minanga Sur 713

Minanga Norte 397

Nicolas Agatep 884

Peru 1,807

San Pedro 1,644Sicalao 1,508

Tagao 376

Tucalan Passing 844

Viga 712

Nabannagan East 1,183

Nabannagan West 2,519

New Orlins 1,065

TOTAL 36,646



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COVERAGE OF THE PROJECT

The project will involve 141 farmers from Barangay Cabatacan East with a service

area of 155 hectares of agricultural lands suitable to rice.

VARIOUS TECHNICAL CONDITION OF THE STUDY AREA

A. Topography and Slope Classification

The service area is generally flat in terrain. According to the Bureau of Soils,

the study area is among the 14,000 hectares or 60% of the total area of Lasam

town that has a 0.30 slope which is level to nearly level. These land area are suitedfor agriculture.

B. Meteorology and Hydrologic Investigation:

The water source of the proposed service area is the Tucalan Creek and

some tributaries.

C. Climate:

Under the climatic classification, the climate at the project area fall generally

under Type III, i.e. rainfall is more or less evenly distributed throughout the year.

Seasonal very pronounced, relatively dry from November to April and wet during the

rest of the year.

D. Rainfall:

The project area is on the windward side during the northeast monsoon so

that rainfall is generally heavy during this part of the year. Although the northeast

monsoon season starts affecting the country by the later part of October and last in

the month of April, rainfall generally declines significantly in the project area by

February.

The period March to April which covers the later part of the northeast

monsoon season and the trade wind season has generally the lowest rain fall during

the year.



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The project area is on the leeward side during the southeast monsoon from

May to the later part of October, however, the area still receives substantial amount

of rainfall during the period especially during the period from August to October.

E. Flood Studies:

Flood study to evaluate the occurrence of flood at the proposed damsite were

not undertaken, however there were accurate information of flooding in the area.

F. Sedimentation:

There is no data on suspended bed load sediments for Tucalan Creek, hence,

the sedimentation rate of this creek was based on the studies for various watershed

in northern luzon. In the sedimentation studies at Magat River Reservoir, erosion

rates are from 0.75 mm/year to 1.55 mm/year. As far as the sedimentation study is

concerned wherein denudation or deforestation is extensive at the drainage area it

can be presumed that there are erosions considering the present situation of the

upper section of the damsite which is actually silted.

G. Water Quality:

The water flowing at the Tucalan Creek is 100% suitable for irrigation.

Tucalan CIS had been diverting water from Tucalan Creek for some years ago. It

was found out that there is no harmful effect that have been noted and recorded.

Water Resource Plan Tucalan Communal Irrigation System 10 of39


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GENERAL LAYOUT OF TUCALAN COMMUNAL IRRIGATION SYSTEM



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Pictorials of the Existing Condition of the Study Area

Canal Structures

Some canal structures are heavily

silted and clogged with debris. Steel

gate of gated structure as shown

above were already out of place and

others were damaged with passing ofeach cropping season.



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Canalization

The condition of main canals and laterals needs rehabilitation. Lined canals werecracked that results to seepage loses. Most of the stretch of canal are heavily siltedwhich lessen the capacity to carry the flow of water, thus, decrease in the efficiency.



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Service Road

This is the portion of service road that needs rehabilitation like surface stabilizationand gravelling. This will ensure convenience in the mobility of crop production andeasy access to different farm site.

Diversion Dam

Washout portion of the overflow damgreatly affects the efficiency andfunctionality of the irrigation systemespecially to quantity of water beingdiverted to canal networks.



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Institutional Development

The situation shows that there is no management plan for cropping schedule of

farming. This results to the inefficient use of irrigation water.



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AGRICULTURE CONDITION OFTHE STUDY AREA

Rice is the principal crop of the project area. Depth of water needed during

land preparation is 150 mm, maximum. Reduce water depth from 20-50 mm during

transplanting and 5 days after the end of transplanting, increase and maintain the

depth of water from 25-75 mm with maximum of 150 mm until 14 days before

harvesting.

Provision for water losses includes seepage, leakage and consumptive use of

vegetation on the slope and/or along the stretch of the canal, the operational losses

on account of some damaged structures, excess delivery and waste water incurred

during transplanting and poor maintenance of paddy field dikes.

A. Vegetative Cover

The Tucalan Creek water shed area as estimated from the 1:50,000 m scale

military map is 13.20 square kms. The drainage area is heavily forested despite the

presence of selective logging operation. The low lying hills portions show baldness

for no big forest trees is present. Tall grasses like bamboos, bohos, shrubs, cogons

and those belonging to gramineae family are found.

Some of the low land rice areas are found at the foot of the hills. On

established paddy fields, the dominant grasses are cogon, and talahib. Other

common grasses are echinochloa glabrescens, echinochloa coloma, cyperius iria,

fimbristylis littoralis, ipomoea aquatica and monochoria vaginalis.

B. Soil Type

The general soil type of the service area is clayey and loamy types. These

soil types crack easily upon drying; however it becomes soft within few hours after

saturation. Along hillside in cultivated areas the soil dries to a depth from 50-70 cm

or more.



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C. Land Use

The service area of 155 has is cultivated and planted to rice. Originally the

area is irrigated. However, since the dam was washout the area became rain fed

rice paddies.

D. Land Ownership

Approximately the distribution of land ownership is as follows:

OWNERSHIP/CULTIVATORSHIP DISTRIBUTION BY PERCENTAGE

AREA FARMERS

Full Owner 73.90 84

Share Tenants 11.00 22

Lease Holder 14.20 15

Amortizing Owner - -

Full Owner & Lease Holder 39.50 10

Full Owner & Share Tenants 11.80 7

Share Tenant & Lease Holder 4.60 3

Full Owner & Amortizing Owner - - _______

T O T A L 155 141

AGRO-ECONOMIC DATA

A. General:

To ascertain the economic viability of

the project an agro-economic survey

was conducted. The method and

approach was through interview of

randomly picked farmer beneficiaries.

Information was also obtained from

other government entities national

and local who are involved with the

different data. These pieces of

information and data were compiled,Water Resource Plan Tucalan Communal Irrigation System 17 of39


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transcribed and consolidated and became the basis of projection and estimate of the

project.

B. Present Production

The present average production per hectare for rainfed areas is 2.50 tons/ha. The

present family net income of owner-operator for one (1) hectare rainfed rice is

P17,104.00 annually. This meager farm net income cannot sustain the economic

needs of the farmer, thus an irrigation system is vital to increase the rice production.

Marketing of farm product in the area is not a problem. The farmers sell their

palay to traders at the poblacion, others sell their products at NFA warehouse at

Allacapan, Cagayan.

IDENTIFIED UNCERTAINTIES

1. Calamities and Weather Disturbances

This Water Resource Plan aims at establishing a sustainable and functional

irrigation system to improve the agricultural potentials of the study area. But

because of calamities and weather disturbances such as typhoons, excessive

flooding, El Nino, La Nina and others, risks that may lead to the destruction of

irrigation infrastructures, access roads and casualty on crops are at stake.

2. Production Cost

In recent years, high prices of agricultural supplies such as hybrid seeds,

fertilizers, insecticides and pesticides is one of the major burdens of farmers.

It is also aggravated by the low market price of crop yields because trading is

monopolized by private individuals. As an adverse effect, farmers might suffer

indebtedness that will affect their quality of living.

3. Fund Source

In Philippine setting, realization of various infrastructure projects like this

water resource plan depends on government funds. In most cases, there are

limited available budget for the restoration and rehabilitation of existing

irrigation infrastructures to sustain its functionality. This has been the scenarioWater Resource Plan Tucalan Communal Irrigation System 18 of39


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for Tucalan Communal Irrigation System. Funds may be available for certain

year but uncertain of its next funding period.

4. Political Will and Rapid Changing Priorities

Because most of infrastructure projects are government funded, it takes a

political will to ensure the potentials of the irrigation projects. These irrigation

projects like the Tucalan CIS might be affected by the changing priorities of

government officials as an effect of the transition of political administration.

5. Accessibility/ Isolation of Production Area.

The study area has 1.20 kilometers without proper access road which was

included in this project plan to be developed. Problems in the future may

include the maintenance for the serviceability of the access roads.

6. Irrigation Association Capability

The functionality and operation of the irrigation system depends on the

effectiveness of Irrigator Association in carrying out irrigation management

plan. Failure to establish its stability might hamper the optimum utilization of

the system.

ALTERNATIVES

In determining the project irrigation requirements, all the above mentioned technical

data and agricultural conditions were considered. For instance the cropping

calendar shows that land preparation is set during the first week of May and

September. Transplanting and vegetative or growth management follows until the

start of harvesting which falls on the first week of October and February to complete

a year-round cropping season. Another two and one half months (2) period is

provided for repair and maintenance of the system before the on-set of the first

cropping season of the following year.

Three alternatives were identified for the project to suit the existing conditions: (1)

Overflow-Type Weir, (2) Pump Irrigation Project (PIP) and (3) Shalow Tube Well.



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Alternative 1: Overflow-Type Weir

Scope

This alternative involves the modification of the intake and earthfill dam across the

Tucalan Creek to harness the potentials of the stream for irrigation. Major

components of the project include the rehabilitation of irrigation and drainage

network to ensure irrigation water will reach the whole service area. Other items of

work will also include the provision of service road along the existing canal network

and farm level facilities to guarantee efficient water delivery into the paddy level.

Environmental Impact

Results of field investigation conducted have revealed that there are no human

settlements that could be affected in the diversion works location and with the stretch

of the diversion canal to be undertaken.

As far as the project is not within the environmentally critical areas, considering the

works to be undertaken does not require massive excavation or quarrying, no big

trees will be cut down nor reforestation areas will be traversed by canal, hence it is

possible to ascertain within the project area, that there are no archeological sites,

historical or native landmarks that will prejudice development of the project.

Investment Cost


OVERFLOW-WEIR TYPE OF DAM


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The total investment cost of the project amounted to P18,382,002.56. This includes

old loans amounted to P413,922.68. and this program for construction amounted to

P18,600,000.00. Total Project Cost is P19,013,927.00 and the development cost is

P122,670.47/ha.

The estimated cost breakdown is as follows:

Items of Work (Balance of Old Loan) This Investment Total Investment

Diversion Works P 260,869.02 P1,439,660.00 P 1,700,529.02

Canalization 153,053.66 10,356,850.00 10,509,903.66

Canal Structure 3,286,100.00 3,286,100.00

Terminal Facilities 303,505.00 303,505.00

Drainage Facilities 100,000.00 100,000.00

Project Facilities 75,000.00 75,000.00

Service O & M Road 800,000.00 800,000.00

Total Direct Cost P 413,922.68 P16,361,115.00 P16,775,037.68

GESA 818,056.00 818,056.00

Institutional 490,833.00 490,833.00

Management Fee 930,000.00 930,000.00

Total Indirect Cost 2,238,889.00 2,238,889.00

Total Estimated Cost P 413,922.68 P18,600,004.00 P19,013,926.68

To Estimate, Say P19,013,927.00

Economic Internal Rate of return

The final evaluation Economic Internal Rate of Return (EIRR) of the Overflow-Type

Weir yielded 29.35% considering normal plan. However with the foresighted 20%

increased in construction cost it yielded an IRR 23.85%. A 20% increase in

construction cost and two years delay in attaining full project benefits resulted to an

IRR of 22.34%.



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Net Present Values and Benefit-Cost Ratios (NPV/BCR)

At Normal Plan

FUTURE NOMINAL VALUE PRESENT WORTH @ 10%

INV. COST O & M BENEFIT 10% INV. COST O & M BENEFIT

( P'000) ( P'000) ( P'000) D.F. ( P'000) ( P'000) ( P'000)

1 446.96 0.90912 10,042.44 0.8264

3 10,042.44 0.7513

4 779.50 5,792.50 0.6830 532.40 3,956.27

5-50 779.50 5,792.50 6.7449 5,257.65 55,814.04

Total 20,531.84 5,790.05 59,770.31

Net Present Value ( NPV ) = 59,770.31 - ( 16,250.26 + 5,790.05 )

= 37,730.00

Benefit Cost Ratio ( BCR ) = 59,770.31

( 16,250.26 + 5,790.05 )

= 2.71 > 1.00

YEAR

406.338,299.06

7,544.87

16,250.2600

Advantage

1. It can supply water to large irrigation areas.

2. Reservoir form is a good storage of irrigation water that can be used

especially during dry season.

3. The service period efficiency is high compared to other irrigation option that is

why it is the most adopted irrigation component in the Philippines.

DisadvantageWater Resource Plan Tucalan Communal Irrigation System 22 of39

t Normal Plan

FUTURE NOMINAL VALUE ( P'000 ) AT PRESENT WORTH ( P'000 )

Year Benefit on Increment At

Investment Irrigation Benefit DF Value DF Value

446.96 -446.96 0.7692 0.80 -357.5

2 10,042.42 -10042.42 0.5917 0.64 -6427.1

3 10,042.42 -10042.42 0.4552 0.512 -5141.7

4 779.50 5,792.50 +5013.00 0.3501 0.4096 +2053.3

5-50 779.50 8,275.00 +7495.50 1.1671 1.6353 +12257.

T O T A L + 2384.2

5 ( 30-25) ( 2384.27

= 29.35

- 354.15

COST

O & M

At30% 25%

+25INTERNAL RATE OF RETURN ( IRR ) =

-343.80

-5942.10

-4571.30

+1755.05

+8748.00

384.27 - 354.1


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1. Construction cost is quit high.

Alternative 2: Pump Irrigation Project

Scope

The main component of this alternative will involve 2 units-250 watts diesel engines

with a capacity of 3,200 cubic foot per minute. The water delivery component will

include 36 diameter Reinforced Concrete pipe to augment the trapezoidal and

square lined canals. Like the first alternative, other items of work will also include the

rehabilitation of irrigation and drainage network to ensure irrigation water will reach

the irrigable area.

Economic Internal Rate of return

Economic evaluation of this alternative shows that the increased investment cost and

decreased irrigation benefits exert a considerable influence on the Economic Internal

Rate of Return. The variations, however, are relatively slight. An increase of 25% in

the investment cost corresponds to a reduction of 9.13% in the EIRR and a

decreased of 20% in the irrigation benefits reduces the EIRR by about 10.77%

points. The combined effect of the two cases on the EIRR is a reduction of

approximately 18.72% points.


PUMP IRRIGATION PROJECT


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Based on the preceding assumptions and by discounting the cost and benefit

streams over a 12 year period, the EIRR is estimated at 22.46%.

Analysis of with and without project situations yielded to the annual financial gross

value of production is P179,153.44 per average farm lot and the same value for

future without project. For the future with project, annual financial gross value of

production increased to P240,189.94 without costing labor. With the use of farm

budgets, analysis of annual net farm incomes indicate that present net crop income

of P62,474.12 would increased to P91,171.22 per average farm lot with the project.

The difference in net crop incomes between the present and the future situations

with project are substantial in determining adequate incentives to farmer

beneficiaries.

Benefit-Cost Ratio

The project has a benefit-Cost Ratio of 1.51 considering incremental benefits for a

15 year period at 15% discount rate of P8,591,680.00 and total Cost of

P5,702,940.00.

Investment Cost

The total project cost was estimated at P9,842,025.30 with the following breakdown:

Item of Work Amount

I. Canalization

3,000 PSI Reinforced Concrete 79,718.10

Structure Excavation 59,361.10

Installation of 36 diameter RCP 582,782.00

Structure Backfill with Compaction 27,062.50

II. Laterals (Lined Canal) 8,251,101.60

III. Diesel Engines (2-250 watt) 842,000,00

Total Project Cost 9,842,025.30

Environmental Impact

There is no significant environmental impact expected from the pump irrigation

project. As with the first alternative, works to be undertaken does not requireWater Resource Plan Tucalan Communal Irrigation System 24 of39


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massive excavation or quarrying, no big trees will be cut down nor reforestation

areas will be traversed by canalization.

Advantage

1. Pump is essential if irrigation by gravity is not possible.

Disadvantage

1. When pumps and other equipments break down, the resulting lack of water

can be critical for plant growth.

2. The cost of pumping water increases with the size of the service area.

Therefore, its irrigated service area is limited.

3. Functionality of the irrigation system declines as the efficiency of pump

decreases.

4. Cost of maintenance is expensive considering the continuous increase in the

price of diesel and machine spare parts.

Alternative 3: Shallow Tube Well

Scope

The Shallow Tube Well alternative will comprise 16 units of 2.5 Hp pump engines

drilled on site and involves well boring and development. Suction pipes will be

encased and will deliver water into the main canals.


SHALLOW TUBE WELL


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Investment Cost

Total cost for the Shallow Tube Well is P6,528,977.20 and will have the following

items of work:

1. Pipe Casing2. Well Development3. Pumping Test4. Suction Pipe5. Pump & Engine6. Excavation7. Pump Chamber8. Stilling Basin

Operation and Maintenance Cost

Considerations in computing the operation and maintenance cost per hectare of rice

is as follows:

AssumptionsCost of Palay Per Cavan PhP 450.00Fuel Consumption Factor Per Pump Tear 0.6

Crop Water Requirement for Rice Per Day 0.008Crop Maintenance 89

(Number of Days Per Cropping)Irrigation Water Requirement Per Hectare (cu m/ha) 7,120Pumping Hours Required (hrs) 152.14Assumed Cost of Diesel (PhP/Liter) PhP 25.00

Energy CostCost (Fuel Cost Per Hectare) PhP 2,282.05Consumption (Liters) 91.28

Repair and maintenanceOil and Parts PhP 200.00Operator Php 216.00Well PhP 800.00

Replacement Cost (Every 10 Years) PhP 680.00

Total Estimated Operation and Maintenance Cost PhP952,595.70

Advantage

1. Good for small-scale irrigation projects

Disadvantage

1. The amount of water that can be abstracted from shallow well is limited, and,

as a result, the areas which are irrigated from this water source will also be



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limited.

2. Excessive exploitation of the ground water by many users, however, will bring

about a decline in the water table.

3. Source of shallow tube well are likely to be very thin with a limited storage

capacity for ground water..

MULTI-CRITERIA ANALYSIS

The three alternatives were subjected to a multi-criteria analysis in order todetermine which option is most responsive in terms of achieving the short-term andlong-term objectives of the project. Three criteria were selected: Impact onProduction, Social Equity and Sustainability.

Criteria 1: Impact on ProductionThe provision of the irrigation system and the transfer of appropriate farmingtechnologies to the beneficiaries directly translate to the extension of areas forcultivation, crop intensification and adoption of modern crop varieties.Adequate irrigation water supply also results to higher agricultural outputswithin the projects influence area. Consequently, higher production yieldsignificantly contributes to the increase in the average household income ofthe farmers. The element to be rated in this criteria is the Yieldof Productionrepresented as the ratio of the average annual volume of production (in ton)and the area of production (in hectare).

Alternative 1

The Overflow-Type Weir is expected to irrigate the whole service area of 155

hectares during the first cropping and 75 hectares during the second

cropping. This will increase cropping intensity by 148% and will improve palay

production from 387.50 tons to 1,150 tons annually. Production yield of 6.2

tons per hectare will result to an increase in average annual on-farm income

from P17,104.00 to P53,379.87.

Alternative 2

The Pump Irrigation Project will increase cropping intensity by 130% and is

expected to irrigate 155 hectares during the first cropping and 47 hectares

during the succeeding cropping season. While the whole irrigable area will be

serviceable during the main cropping period, the projected low water level of

the stream during the dry season which coincides with the second cropping

will drastically affect the volume of source water. The annual volume of

production is projected at 700 tons and yield is computed at 4.5 tons per

hectare.



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Alternative 3

The Shallow Tube Well is expected to irrigate the whole service area of 155

hectares during the main cropping. However, based on available aquifer data

in the area available water source will serve only 39 hectares during the

second cropping which will achieve a cropping intensity of 125%. Over theyears this is projected to decrease as aquifer levels will be critically depleted

especially during pronounced dry seasons. Volume of production is estimated

at 670 tons and a yield of 4.3 tons per hectare.

The Overflow-Type Weir best satisfies the Criteria on Impact of Production as

presented above. It posted the highest relative weight of 36%.

Criteria 2: Social Equity

A demand-driven and equity-based approach is adopted in the

implementation of the project. Social equity refers to the involvement of the

project beneficiaries in whole process of project development from planning,

design, construction and operation. This will encourage them to actively

participate in the implementation of the project. The provision of equity or

counterpart from the beneficiaries is crucial and significant in ensuring the

achievement of the projects purpose. Social equity also requires the

establishment of a stable Peoples Organization to manage and supervise the

operation and maintenance of the project. The element to be rated in this

criteria is the relative participation and involvement of the beneficiaries in

terms of labor provided (jobs generated) and the amount of counterpart fund

contributed (pesos). The alternative with the most jobs generated in theconstruction of the project and with the highest counterpart fund provided will

best satisfy the social equity criteria.


Alternative

1 6.29 tons/ha 35.86%

2 4.51 tons/ha 32.61%

3 4.36 tons/ha 31.53%

Production Yield Weight

Impact on Production Criteria

Alternative Weight

1 53.73%

2 27.81%

18.45

oc a qu ty r ter

984,202.53

652,897.72

128

66

44

Counterpart

Fund (PhP)

Jobs

Generated

1,901,392.70


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In terms of the Social Equity Criteria, Alternative 1 (Overflow-Type Weir)

posted the highest relative weight of 54%.

Criteria 3: Sustainability

The project must be sustainable so that local mechanisms will be in place to

ensure that the community shall continue to benefit long after the project is

completed. The sustainability criteria will look into the optimum usable lifespan

of the project including the level of investment required for the maintenance of

the structures and facilities. An outright observation of the three alternatives is

that the project cost is inversely proportional to the cost of maintenance. On

the other hand, the total project cost is in direct proportion to the projected

usable lifespan of the project.

The alternative with the highest incidence of sustainability is the Overflow-

Type Weir with a relative weight of 61%.

COMPARATIVE ANALYSIS

1. Summary of Alternatives

2. A comparative evaluation of the three alternatives shows that the Overflow-Type

Weir (Alternative 1) provides the best option in terms of higher Economic Internal

Rate of Return and Benefit-Cost Ratio.


Alternative Weight

1 60.98%

2 24.39%

3 14.63%952,595.70 8-12

175,537.50 25-50

1,054,000.00 15-20

Sustainability Criteri

Maintenance

Cost (PhP)Lifespan (Yrs)

1 Overflow-Type Weir 19,013,927.00 29.35 2.71 175,537.50

2 Pump Irrigation System 9,842,025.30 22.46 1.51 1,054,000.00

3 Shallow Tube Well 6,528,977.20 - - 952,595.70

Alternative EIRR (%) BCR O&M Cost (PhP)Total Project

Cost


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3. The EIRR of Alternative 1 is 7% percent higher than Alternative 2 and 120%

higher in terms of BCR. The Overflow-Type Weir is also most advantageous in terms

of O&M cost with a 1% O&M Cost Project Cost ratio.

4. Since the irrigable service area is large, over-flow weir is best suited for its

capacity to supply water to larger areas.

5. The source of irrigation water when the overflow-type weir is adopted (Tucalan

Creek) would be sufficient to meet the diversion requirements for the service area

based on the discharge capacity of Tucalan Creek and its nearby tributaries. The two

other alternatives pose uncertainties on underground water source.

Based on the comparative analysis of the three alternatives, the Overflow-Type weir

was selected for implementation in the project area. Though more expensive than

the other options, it is chosen for its high incidence of sustainability.

IMPLEMENTATION

Scheme of Development

The design approach for all items of work shall conform to NIA standards and

specifications for irrigation projects.

1. Diversion Works

This involves the repair of the earthfill type diversion dam across Tucalan

Creek at approximately 180500 N latitude and 1212815.90 E longitude. Thedam will serve to divert the flow of water thru a gated intake structure, which will

regulate the flow of irrigation water to the canal network. Although it is not of the

impounding type, the dam was originally constructed as earthfill because of the very

wide section of the diversion site. The height of the dam to command the highest

portion of the area entails high cost if concrete-overflow type is adopted.

2. Canalization:



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This involves the rehabilitation of dilapidated canal system from the existing

outlet of intake up to the tail end of both the main canal and lateral canals.

3. Canal Structures:

This involves the construction of additional canal structures along the stretch

of canal system, repair of damaged structures and replacement of all siphon

structures to flume.

4. Terminal Facilities:

This involves the construction of additional turn-out structures, construction of

main farm ditches and supplementary farm ditches to efficiently deliver water to the

farm level.

5. Service / Access Road:

It involves the repair of 1.20 kms existing dirt road from the barangay road to

Cabalacan West leading to the diversion dam and construction of service roads

along the canal system.

6. Drainage Facilities

It involves the construction of drainage culverts along waterways and

depression areas being traversed by the system.

7. Project Facilities:

This involves the construction of bunkhouse in the project area to be used

during construction period.

Construction Scheme and Schedule

The project will be under the supervision of the Provincial Irrigation Engineer

of Cagayan-Batanes. The proposed works will be undertaken into two categories

force account works and contract works, major item of work will be awarded to

contractors requiring the utilization of heavy equipments, while minor work and other

work requiring intensive labor will be done by force account works to promote

participation of farmer-beneficiaries during construction. In this process the projectWater Resource Plan Tucalan Communal Irrigation System 31 of39


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could generate 10% equity thru labor. Another way to generate equity, the farmer-

beneficiaries could give cash or construction materials. The project will be

scheduled for construction for 2 years.

OPERATION AND MAINTENANCE

Technical:

1. Dam & ReservoirFor dam and reservoir to function properly the following are somemaintenance works that should be undertaken:

a. Clearing of the reservoir area of any debris or floating materials

b. Regular de-silting of the reservoir

c. Restoration of upstream and downstream slope of the embankment

d. Repair of upstream slope riprap.

e. Repair of water gauge or staff gauge in the reservoir.

2. Spillway

The spillway should always be capable of releasing probable excessfloodwaters from the reservoir.

a. The approach channel of the spillway should always be free of any obstructionor temporary structures.

b. Repair of riprap in the approach, discharge and terminal sections should be donewhen necessary.

3. Irrigation Distribution System

a. Checking of any leakage or malfunctioning of the outlet structure.

b. Cleaning and cutting of grasses in irrigation canal & embankment

c. Removal of debris that can obstruct the flow of water along canals & canalembankment.

d. Removal of silt deposits on canal bottom w/c can lessen the capacity of irrigationcanals.

3. Paddy Fields (farmer beneficiaries party)



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a. Leveling of paddy fields for even distribution of applied water.

b. Height of paddy dikes must be maintained to not less than 20 cm to prevent overtopping or spillage of water.

c. Paddy dikes should be properly compacted & plastered to minimize seepage flow.

d. Farm ditches should be properly constructed & maintained such that each farmcan receive its equitable share of water.

e. Additional paddy spillways provided for upland irrigations should be properlyclosed during lowland irrigation.

Agro-Economic/ Financial

At full development, production from the project area is expected to increase from

2.50 tons/hectare to 5 tons/hectare for the first crop and 5 tons/hectare for the

second crop. The cropping intensity will increase up to 148 % in the whole service

area. The production is expected to reach 1,150 tons annually in the whole area from

the present 387.50 tons. Annual net income is expected to increase from P

17,104.00 to P53,379.87. These benefits are successfully attained with the

application of farming innovations and policies. Irrigation by itself cannot do much

way of development, but combined with other factors may create a potentially

favorable situation for agricultural development. Other program supports such as

credit sources, extension services and creation of money-lending cooperative in the

association which has been shown to be inadequate in the area will

have to be established and strengthened.

Social Requirements

The project after completion and successful test run of its facilities will be turned over

to the Irrigators Association (IA) for operation and maintenance. Training and

seminars will be conducted in order to assist the Irrigators Association as regard to

proper Irrigation System Operation, Maintenance and Management. In this aspect

the IA will be able to acquire knowledge to formulate their own plans and strategies

applicable to their needs.



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Impact of the Water Resource Plan

The water resource plan for Tucalan Communal Irrigation System is designed to

make a sustainable management of water and re-establishment of the operation and

functionality of its irrigation components. Its impact in the increase of crop production

contributes to social transformation and economic development of the area including

the municipality itself.

1. Urban Center and Commercial Development

Beneficiaries seek to attain higher educational learning to further

improve quality of living.

With the increase of income for every household, consumption of

various commodities and services would also increase. This will lead to

commercial development on the area as well as nearby business

centers.

2. Human Settlement areas

In the fulfillment of quality living, beneficiaries choose to have quality

construction materials for their houses. They also strive to achieve

electrical services for household purposes.

3. Additional Roads

The well-planned operation and maintenance of the irrigation system

will create a continuous improvement of farm-to-market roads. These

includes clearing, surface stabilization and gravelling of road networks.

Aside from the convenience it provides, the cost of transporting farm

production will be minimized.



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CLIMATE MAP


THIS SITE


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LAND CLASSIFICATION MAP



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LAND USE MAP



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SOIL MAP



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ANNEXES

water resources plan

Documents