ENVIS is a project of Ministry of Environment & Forests, Govt. of India, under the World Bank aided EMCBTA Project

June 2003

ENVIS Newsletter State Environment Related Issues

Vol.1 No.2 SPECIAL ISSUE - WORLD ENVIRONMENT DAY

The state of Karnataka is facing severe drought from the past two years. The situation has continued

for the third Consecutive year 2003 due to the failure in the South-West monsoon. (June to September 2002)

and the North-East monsoon (October to December) monsoon rains.

The South-West monsoon 2002 (June-September) was not good as the state received an average rainfall of

541 mm which is 32% less than the seasonal normal of 805 mm. The South-West monsoon was in deficit in

26 of 27 districts and in 149 of the 175 taluks of the state.

World Environment Day 2003

DEPARTMENT OF FORESTS, ECOLOGY & ENVIRONMENT, GOVERNMENT OF KARNATAKA

The rainfall pattern during the period January 2003 to may has

also not improved. Out of 175 taluks in the state 153 taluks

recorded deficit in rainfall during this period. The percentage of

departure of rainfall is -53% from the normal. The areas of

Coastal Karnataka recorded the maximum departure of -67%

(145/48mm).

If there is magic on this planet, it is contained in water. - Loran Eisely

Rainfall trend in Karnataka 1996-2002

700

800

900

1000

1100

1200

1300

1400

1996

1997

1998

1999

2000

2001

2002

(Pro

vis

ional)

Ra

infa

llin

mm

Recorded Rainfall Normal

Source: Drought Monitoring Cell, GoK

So

urc

e: D

rou

gh

t M

on

ito

rin

g C

ell,

Go

K

-13

-26

-13

-28 -29

-13

-29

-55

-24-27

-48

-31

-37

-26

-17-14

-36

-24

-37

-7 -9

-53

41

33

15

29

20

4 4 4

16 17

30

3

-60

-40

-20

0

20

40

60

19

70

19

72

19

74

19

76

19

78

19

80

19

82

19

84

19

86

19

88

19

90

19

92

19

94

19

96

19

98

20

00

20

02

Years

%D

ep

art

ure

fro

mR

ain

fall

% Departure of Rainfall from Normal (Jan 2003 to May 2003)Comparison of 2003 with last 33 years

In this issueRecharge of Ground water -2Rainwater Harvesting - 3

Parameters influencing rooftop RWH - 5Myths about water - 6Cloud Seeding - 7

Groundwater

Ground water has been the main source for irrigation and drinking purposes, particularly in rural areas. More

than 90 percent of rural public water supply schemes depend on ground water. With increasing water

scarcity problem, ground water is becoming a major source for private water supply in urban areas. Due to

this pressure from rural and urban sector, ground water resources are depleting.

Groundwater Status in Karnataka

11%2% 2%

85%

Safe Overexploited Critical Semi critical

So

urc

e: H

ydro

log

y P

roje

ct, D

MG

, 2

00

3

Total watersheds : 380(300-1400 sq. Km. Range)

Ground water survey reports of 1999 reveal that there is depletion of ground water resources in 56

watersheds in the State, which are spread over 35 taluks in 10 districts, covering 5692 villages.

Based on the study of historical data, ground water levels are reported to be declining in all parts of the

State, except in some command areas. In view of the expected rise in demand for surface water for drinking

purposes in urban areas and continuing dependence on ground water for rural drinking water supply, the

shortage of ground water resources are likely to be felt increasingly during the coming years particularly in

some critical areas of the State. With decline in surface water availability for agriculture due to rising

domestic demand, ground water extraction for irrigation may increase in near future. In the absence of any

regulatory mechanism, there would be greater pressure on existing ground aquifer. Of the total 1895 wells

under observation by the Dept of Mines & Geology, water level showed an increase in 418 (22%) wells while,

decline was observed in 1109(56%) wells(Mines & Geology,2002). Uneven and scanty rainfall and the geo-

structure have restricted the availability of underground water resources in the State.

RECHARGE OF GROUNDWATER

Ground water usually has the great advantage over surface water, as it is free from pathogenic organisms.

Moreover, in the arid and semiarid regions, surface water evaporates at a faster rate, leaving concentrated

salts on the surface. However, ground water too is not always available and the amount that can be

withdrawn is usually limited. But under suitable situations it is possible to supplement the natural recharge of

ground water aquifer so as to add to its capacity.

Recharge replenishes water in aquifers, or is discharged in springs, streams, lakes or wetlands. There are

several different processes by which groundwater recharge may occur. Recent and renewable recharge is

derived naturally from precipitation, or Water may simply leak through the base or banks of rivers and

streams, or from wetlands, dams and reservoirs, and percolate to the saturated zone within underlying

aquifers. In addition, recharge may be induced by anthropogenic activities that are intentional, such as

injection wells, slopes, trenches, seepage ponds or percolation tanks, which obstruct the flow of ephemeral

streams. The water is stored in the sediment below ground surface and can be used for aquifer recharge.

2Water is the best of all things. - Pindar

Rain Water Harvesting

RWH can be defined as the process of collecting and storing rainwater in a scientific and controlled manner

for future use. A more apt and accepted definition for RWH is 'Catching water where it falls' thus seeking to

eliminate or atleast minimise inter-basim or inter-catchment transfers in a specific locale.

Forms of RWH

Forms of RWH in an urban context include

! Rooftop RWH

! RWH in paved and unpaved areas i.e., landscapes, open fields, parks, storm water drains, roads,

pavements and other open areas, etc.,

! RWH in lakes and tanks.

Forms and methods of RWH

! Rooftop RWH from buildings of different uses-residential, commercial, industrial etc.

! Runoff RWH from landscapes, open fields, parks, storm-water drains, roads, pavements and other

open areas, green belts, etc.

! Natural storage and collection through Lakes and Tanks.

UNIQUE ADVANTAGES OF RWH

! Capturing rainwater insitu and agumenting water supply at a marginal cost

! Replenshing groundwater through recharging of rainwater by using the soil column

! Reducing pollution and contamination

! Providing clean and safe water

! Least capital investment with maximum benefits at household as well as city levels

Source:.. A Conceptual Frame for Rainwater harvesting

in Bangalore, DEE, GoK & STEM.. www.rainwaterclub.org

On a larger, regional scale, recharge from shallow to deeper aquifers also takes place. It's possible to take

the path of recharge to a deeper aquifer back up to the geographic areas of entry in the surface landscape.

These are known as recharge areas. The lowest recharge rates occur in areas of fine-grained, low

permeability soils, such as clay plains. More permeable soils such as sand and gravel allow higher recharge

rates. The recharge rate is also influenced by climate, topography and vegetation cover.

The total groundwater pumped from all wells in an aquifer should be less than the amount of recharge to that

aquifer. If not, the water level in the aquifer is gradually lowered, depleting the reserve of groundwater.

Advantages of Groundwater Recharge

J Groundwater recharge stores water during the wet season for use in the dry season, when demand is

highest.

J The use of aquifers for storage and distribution of water and removal of contaminants by natural

cleaning processes which occur as polluted rain and surface water infiltrate the soil and percolate

down through the various geological formations.

J Aquifer water can be improved by recharging with high quality injected water.

J Recharge can significantly increase the sustainable yield of an aquifer.

J Recharge methods are environmentally attractive, particularly in arid regions.

3When the well is dry, we know the worth of water. - Benjamin Franklin,

It makes ecological and financial sense not to waste a pure natural resource available in large

quantity on one’s roof.

Ground water sources are increasingly getting depleted or are getting polluted.

Borewells are either silting up, getting short of water or are drawing polluted water.

Private purchase of water from tankers is unreliable in quality and is also expensive.

It encourages water conservation and self-dependence.

5 good reasons to Harvest Rain water

In the Urban context, significant portion of the city is built-up. As the population of city grows, and develops

economically, rate of built up area also increases. The construction of buildings at present let off the roof top

rainwater into the storm water drains outside the plot area.

Roof tops being of a significantly hard material generate large quantities of rainwater runoff as the losses

due to evaporation and percolation are limited. This rooftop rainwater can be used by storing or by

recharging the aquifers.

The stored rainwater can be used for domestic washing and gardening purposes.

Rooftop Rainwater Harvesting & Groundwater Recharge

Rainwater Enters Underground Aquifers

Raw Water for Washingand Gardening

4Filthy water cannot be washed. - West African Proverb

Rainfall quantity (mm/year): The total amount of water becoming available to the consumer depends

upon the total rainfall in a year and the rooftop surface available for collection. Usually a coefficient of loss

accounting for evaporation, first flush, etc. has to be incorporated into the calculations. Mean annual rainfall

data will enable calculation of annual likely availability of rooftop rainfall water.

Rainfall pattern: Apart from the total rainfall in a year, the pattern of rainfall whether evenly distributed

through the year or concentrated in certain periods will determine the storage requirement. The more

distributed the pattern the lesser the size of the storage, the single costliest component of a rooftop

rainwater system.

Collection surface (sq. m): The more the rooftop area the higher the collection. The better the quality of

the collection surface the more the collection. Maintenance of the collection surface in keeping it clean is

also a function of the quality of the material used and rooftop accessibility.

Storage capacity: Since the storage system is the most expensive component of rooftop RWH an optimal

design for storage becomes crucial to reducing cost of rooftop rainwater harvested.

Daily consumption of water (Ipcd): This varies from household to household based on habits and also

from season to season. Consumption rate has an impact on storage systems design as well as the duration

to which stored rainwater can last.

Number of users: This has a significant influence on rooftop RWH system design. The greater the number

of persons, greater would be the storage capacity required to achieve the same efficiency of fewer people

under the same roof area.

Cost: This is probably the most important component of rooftop RWH designs. Alternative sources of water:

If for certain reasons alternative sources are not available or are expensive, then rooftop RWH becomes a

useful solution.

Parameters influencing Rooftop RWH

Rainwater Harvesting Links

http://www.cgwaindia.com/ - The official web site of the Central Ground Water Authority of India provides a

primer on rainwater harvesting, including how to do it, costs, safety considerations, case studies, and using

rainwater for artificial recharge of groundwater aquifers.

http://www.aboutrainwaterharvesting.com/ - Information on the history of water harvesting

methodologies in Tamilnadu (India) and the modern methods adopted for rain water harvesting structures

and advised by TWAD Board for both individuals and professionals.

Http://www.rainwaterharvesting.org/methods/modern/gwdams.htm - CSE is a public interest research

and advocacy organisation which promotes environmentally sound and equitable development strategies.

http://www.irpaa.org.br/colheita/index.htm - Rainwater harvesting in Rural areas.

5Water is its mater and matrix, mother and medium. Water is the most extraordinary substance! - Albert Szent-Gyorgyi

Below are some of the more common misconceptions about groundwater, runoff and crop water use.

Subscription to myths such as these can lead to poor decision-making and wastage of human and financial

resources.

The observation that water tables have risen in wells that are immediately adjacent to check dams is often

recounted as an indicator of success of watershed development programmes. Unfortunately, many such

reports fail to recognise the fact that, in semi-aridareas that are underlain by hard rock aquifers, structures

such as check dams, even in the absence of increased groundwater extraction, rarely lead to regional rises

in groundwater water levels.

The reality is that check dams and other such water-harvesting structures usually have only localised

impacts on the watertable and aquifers rarely behave like underground lakes (i.e. That localised recharge in

one place leads to an immediate rise in groundwater levels at another place many hundreds of metres

away). Aquifers are geological formations that contain groundwater. In simple terms, ground water is water

that accumulates underground and is stored in the pore spaces that exist in sediments or weathered

materials and/or in the fractures in rocks such as granites or basalts. Ground water is in continuous slow

motion in the direction of potential gradients that are created by gravity and capillary forces. In areas of

permeable subsoil, excess rain water travels through the soil and the unsaturated layer below. When it

reaches the water-table and joins the aquifer, it begins a slow underground journey, typically at rates ranging

from a few millilmetres to a few metres per day. Eventually it finds outlets, such as river beds, wetland

seepages, natural springs etc. Drawing ground water from wells can have a big impact on ground water

regimes and availability. Cones of depression in the water table are created around wells and these

influence potential gradients and hence the speed and direction of water movement

Although localized runoff, and run off from individual storms can be high, annual run off in semi-arid areas - at

scales larger than the micro-watershed tends to be much lower than 30-40percent. In large areas of semi-

arid India, mean annual runoff is lower than 5 percent of annual rainfall. Ground water extraction, soil water

conservation and construction of water harvesting structures have all contributed to a further reduction in

mean annual runoff. This fact explains why, in the areas surveyed by the KAWAD Water Resources Audit,

inflows to tanks are significantly reduced and why rivers that were once perennial are now seasonal.

The worldwide evidence that high hills and Mountains usually have more rainfall and more natural forests

than do the adjacent low lands has Historically led to confusion of cause and effect (Pereira1989). The reality

is that forests exert a small, almost in significant, influence on local rainfall (Calder,1999). Not with standing a

small number of exceptions, catchment experiments generally indicate reduced runoff from forested areas

as compared with those under shorter vegetation (Calder,1999).

AQUIFERS ARE UNDERGROUND LAKES:

RUNOFF IN SEMI-ARID AREAS IS 30-40 % OF ANNUAL RAINFALL

PLANTING TREES INCREASES LOCAL RAINFALL AND RUNOFF

MYTHS ABOUT WATER

6We forget that the water cycle and the life cycle are one. - Jacques Cousteau

RAINFALL HAS DECREASED IN RECENT YEARS

WATER USE OF CROPS DEPENDS MAINLY ON CROP TYPE

AQUIFERS ONCE DEPLETED STAY DEPLETED

Studies of long-term rainfall records have, to date, shown no systematic trends in annual rainfall in semi arid

areas of India, despite widespread reporting to the contrary.

A common misconception is that the daily water use of crops is directly related to the Crop type and that the

evaporation rates from certain crops are many times higher from Some crops as compared to others. The

reality is that, assuming that a crop is well supplied with water, the evaporation process is driven primarily by

the meteorological conditions (e.g. radiation, wind speed, dryness of the air).

A pessimistic view of aquifer depletion is that this is an irreversible process. The reality is that, in most cases,

aquifers can be re-established or replenished as long as the balance between recharge and extraction is

swung towards recharge. This can occur as a result of higher than average rainfall or a reduction in

groundwater extraction. There is nothing inherently wrong in extracting groundwater. So long as supplies of

drinking water, water for domestic use and wildlife are not endangered, extraction of groundwater for

agriculture and other livelihood uses is sensible. Moreover, there is some evidence to suggest that Optimum

use of groundwater resources is good for the long-term 'productivity' of aquifers. For example, in certain are

as of the water sheds surveyed, it appears that increased extraction of groundwater has actually led to an

increase in annual recharge. This is because groundwater extraction has a direct influence on the potential

storage volume of the aquifer, particularly at the beginning of the rainy season

Cloud seeding (also known as weather modification) is the deliberate treatment of certain clouds or cloud

systems with the intent of affecting the precipitation process(es) within those clouds.

However, modern cloud seeding dates from the late 1940's, springing from a discovery at the General

Electric labs in Schenectady, New York in 1946. The ability of dry ice shavings to convert supercooled water

droplets (those existing as water at temperatures colder than freezing) to ice crystals was observed during

the conduct of an unrelated experiment. Later consideration of those observations led to a series of

laboratory trials which demonstrated the nucleating properties of various materials in certain cold cloud

conditions.

The most common intended effects of cloud seeding include precipitation increase (rain and/or snow), fog

dispersal (visibility improvement) and hail suppression. Of these, the majority of operational projects focus

on precipitation increase.

CLOUD SEEDINGSource: http://www.nawcinc.com

7Nature does nothing uselessly - Aristotle

The materials used in cloud seeding include two primary categories, tied to the type of precipitation process

involved. One category includes those which act as glaciogenic (ice-forming) agents, such as silver iodide,

dry ice and compressed liquid propane or carbon dioxide, which are appropriate in cloud systems where the

precipitation process is primarily cold (colder than freezing). Of the ice-forming materials, the most

commonly used is silver iodide. The second major category is focused on cloud systems where the warm

(coalescence) process predominates. In those environments, hygroscopic (water attracting) materials

such as salt, urea and ammonium nitrate can be utilized. Of the hygroscopic materials, the most commonly

used are salts

In cold cloud seeding. the introduction of an ice-forming nucleating agent, e.g., silver iodide, into the

appropriate cloud regions causes supercooled liquid water droplets to freeze. Once these droplets freeze,

the initial ice embryos grow at the expense of the water droplets around them (sublimation) and through

contact with these neighboring water droplets (riming). These embryos, if they remain in favorable cloud

conditions, will grow into snowflakes, falling to the surface as snow if surface temperatures are below or near

freezing, or as raindrops at warmer surface temperatures. This process mimics nature where certain

airborne substances, e.g., soil particles have the ability to act as ice-forming nuclei and initiate the freezing

process. A secondary effect of this process can occur, wherein the freezing of water droplets releases latent

heat of fusion into the cloud. This addition of heat, under the right circumstances, can cause the treated

clouds to grow larger and last longer than would have naturally occurred.

The first freezing process is often referred to as a static seeding effect, increasing the efficiency of the

precipitation process within the seeded cloud volume. The second freezing process, resulting from release

of additional heat into the cloud, is often called the dynamic effect, whereby the treated clouds are

invigorated, thus processing more moisture.

Nature can produce rainfall from clouds that are warmer than freezing. Tiny water droplets that form during

condensation and define the cloud can grow as they collide with one another within the cloud. This process

is known as collision/coalescence. Cloud seeding of this type of cloud involves introduction of additional

condensation nuclei (e.g., salt particles) which can cause additional water droplets to condense within the

cloud. Various modeling and research studies have indicated that this type of seeding is effective in

continental clouds, but ineffective in maritime clouds.

Cold Cloud Seeding

Warm Cloud Seeding