WATER FOR NEXT DECADE

1. Introduction

Water is a very valuable compound freely available in the world and used by plants and all living beings for their existence. In addition to drinking and domestic consumption we use it for agriculture, hydropower generation and for various industries for manufacturing essential goods for consumption and exports. Unlike other countries we are very rich in water, but at the rate at which we consume and waste it in the above process it may not be enough in the future, for the ever growing population, if we do not take adequate steps to use it economically.

Also people cause wanton damages to the environment that helps to preserve water around us by cutting down trees and causing deforestation etc. In 1881 the forest cover of our country was 84% of the land area. In 1900, it was 70%. In 1956 - 1961 a comprehensive survey result showed that the forest cover was 44% (but now it is less than 22%). According to the FAO second inventory carried out in 1982-1985 forest cover was 1.76 million hectares and the scrubland area was 624,000 hectares which is 36%. Previous surveys shows that the rate of deforestation is high.

As we are aware on molecule of water is formed by the combination of two atoms of hydrogen with one atom of Oxygen. Water is freely available in the Globe in oceans, seas, rivers lakes etc. Large quantity of water is available in the atmosphere as water vapour. A certain percentage of water is available in the bodies of human beings, animals and in plants. Water has no colour and it is a very good solvent Due to this property it gets polluted very soon. Water exists in three forms. Viz. solid, liquid and gas depending on the temperature at which it exists.

2. Availability of Water in the World

Seventy five percent of the globe areas is covered with Oceans. Only one fourth is land. This water available in the Oceans is saline and cannot be used freely in that condition for drinking or irrigation purposes in place of fresh water without desalinisation. In the land water both in fresh and saline forms, in soil as soil moisture, in the poles as polar ice, in the form of ice and snow, in lakes, also in marshes, rivers, in fresh and saline forms and as biological and atmospheric water. The areas covered by the water in the Oceans inland lake rivers and lands are 361.3 x 106 km2 and 184.8 x 106 km2 respectively. The quantity of water available in the globe is finite. There is no addition or deduction or whatever losses in quantity with time.

3. Global Annual Water Balance

The three main components that we have to consider when annual water balance in the globe is computed are Precipitation, Evaporation, and Runoff. The above components available in both ocean and land areas have to be taken into account.

Evaporation from the ocean is always more than the precipitation into it. The evaporation from the land is always less than the precipitation and the difference flows to the ocean as runoff. This is to keep the balance in the hydrologic cycle. The runoff to the ocean from the land is 47,000 km3 / per year.

The water that precipitates and then evaporates from the ocean and land areas is the only effective quantity of water that is constantly circulating in the hydrologic cycle. This is the quantity of water that rises to the atmosphere as water vapour and then falls as precipitation, snow, frost etc. The portion of water that falls in the land is being used by the plants and animals for their consumption and by human beings for domestic use, agriculture, hydropower generation etc. There is a large quantity of water in the oceans but cannot be used freely. It is just dead storaf1. It is useful to the human beings as breeding ground for seafood, for extraction of salts, for transport and also for producing wave energy.

4. Hydrologic Cycle

The necessary water and moisture for the living beings is continuously supplied by the nature due to d1e action of the hydrologic cycle. This could be explained as follows. The water vapour in the atmosphere will come down to the earth in different forms. Viz. as precipitation, fog, hail, snow, dew and frost. This happens with the cooling of water vapour. When it condenses due to it! weight it comes down to the earth in the above mentioned forms. Part of this will get evaporate (and return to d1e atmosphere as water vapour, part will run over the surface as surface run-off the balance percolates into d1e ground as infiltration.

The surface run-off flows into streams and rivers and ends up in the oceans. Infiltered water add: to the soil moisture, which increases the ground water storage part of which gets evaporated and return to the atmosphere. Another part of ground water storage flows to the streams and rivers 8: sub surface run-off and end up in the oceans. Water that is evapourated from the oceans, rivers streams lakes etc and from plants as transpiration rises up to the atmosphere, clouds are formed and comes down to the earth in different forms described above with cooling and condensing.

5. Hydrology
The main water source in our country is rainfall. This is responsible for the flow of water in the rivers in the form of runoff. Rainfall has been systematically monitored and studied by the Meteorology Department and river flows by the Irrigation Department for almost a century. This has been utilized for planning and construction of Irrigation projects for the development of Agriculture for food production and hydroelectric projects. The Irrigation Department in 1958 published the first water resources development plan. It must be remembered that our rainfall is controlled by the external forces like Himalayan mountain range and the rain clouds formed over large extent of the Indian Ocean. These rain clouds are carried over to the land by the southwesterly monsoon winds.
Sri Lanka has radial. network of rivers originating from central hills. There are 103 river basins covering 59217, Sq. km. Some of the river basins convey water only during rainy seasons. From the 12.0 x 106 hectares m of water annually received from rainfall 50% is lost througl1 evapotranspiration. 20% seeps down to replenish ground water. Only 30% or 3.5 x 10/ hectare. metre is available as stream-flow for irrigation and other purposes.

Surface water is used for

- Paddy

a. Irrigation -----------

- Other filed crops

b. Hydropower generation

c. Drinking

d. Industry

A substantial proportion of surface water is used for hydropower generation.

Largely water is used for Irrigation and hydropower generation. Today because of large reservoirs constructed under Mahaweli Project major share of the electrical energy is supplied from hydropower. Large reservoirs irrigate over 350,000 ha. of land and have aggregate installed capacity of 938 Mega watts. Pollution of water occurs through out the country from domestic, industrial and agricultural sources. The problem appears to be increasing. Health impacts are the basic indicators of the problem. Less than 25% of the Sri Lankans households have access to pipe borne water. A large majority depends on domestic wells for their water requirements. About 7% draw water from rivers and reservoirs.

About 15000 village tanks mainly in the dry zone that irrigate about 70,000 ha Inland reservoir water now provides 20% of Sri Lanka's Fish production.

6. Water resources of Sri Lanka

Tea rubber coconut and other vegetation, which are rain-fed, covers about 70% of the Agricultural area, while the irrigated paddy accounts for another 25% balance is of other crops. The irrigated paddy lands, is supplemented with water from major and minor irrigation schemes. 85% of the water in the reservoirs is used for irrigation and 15% for the township domestic and other uses.

From the irrigation component 10% of which equivalent to 1.2 x 106 ac.ft infiltrate and add on to the ground water recharge by natural means. This is about 8.8 x 106 ac ft. Therefore total annual recharge of ground water is about l0x 106 ac ft per annum. This is distributed on the basis of Hydrogeology and rainfall distribution. Ground water in wet zone areas is acidic while those in the dry areas can be considered as alkaline and used for irrigation purposes.

When ground water is extracted, reasonable quantities should be extracted always otherwise in coastal areas; salt-water intrusion will takes place. Over extraction of ground water will lead to various environmental problems.

Use of toxic agro-chemicals, fertilizers and insecticides etc. add on to the grolU1d water table and pollute grolU1d water reserve. This will reduce the useful grolU1d water potential. Therefore every endeavor should be taken to reduce the mixing up of above mentioned chemicals with the ground water body.

It is observed that water balance on the annual long-term basis is of the order of:

Mean annual rainfall volume 101 x 106 ac ft

Surface water flows 45 x 106 ac ft

Unharnessed flows to ocean 30 x 106 ac ft

Harnessed and used 15 x 106 ac ft

Evaporation loss 47 x 106 ac ft

Ground water recharge 10 x 106 ac ft (incl. 1.0 x 106 ac ft from artificial recharge)

Though surface flow remains with the deforestation the base flow of the rivers has decreased and flood intensity increased.

7.	Availability of Ground Water

Extraction of ground water usually takes place in dry zone and in arid zones. Tube wells are used for this purpose. The water for irrigation and domestic use is met from the tube wells. Northern and eastern provinces and Puttalam district have a long history for extraction of water from under ground aquifers. Water Resources Board and National Water Supply and Drainage Board are the two Main Organizations carrying out the extraction of ground water on commercial basis. As per records of Water Resources Board the rate of extraction of water at present is satisfactory and gradually meeting the water requirement of the people who have water problems. This has to increase with the increasing population.

The increasing demand for water could be met and the people could have better prospects and facilities if they do not over extract and waste from the tube wells. Water quality in the wells it most of the areas are good for drinking, domestic use and for irrigation, but quality of water available in some dry zone areas is poor, and having dissolved chemical compounds and salts. It is suitable only for irrigation. The key organization for Ground Water studies, Water Resources Board, which is an advisory body, was given implementation functions in 1978.

The ground water division of the irrigation Department was taken over by the WRB. Now the Board is carrying out its functions in commercial level for public and other Organizations. Activities involved are Geo-scientific interpretation of available data for ground water resources development. Hydro-geological investigations for assessment of ground water resources, scientific site locations for deep tube wells. Drilling of deep tube wells for extraction of ground water for domestic, agricultural and industrial purposes. Feasibility studies for ground water resources development. Analysis of water sample for chemical and physical characteristics. Collection of hydro-geological data and preparation of maps.

8. Population

The present population of Sri Lanka is 186 mil people In 2010 the population will be 21.6 x 106 at the present rate of increase of 12%. In 2023 population will be 25 x 106. Increasing population needs food, electricity, water for drinking, domestic use, and for industries Paddy production in the last 10 years is given in Fig. 2 This remains constant (around 2250000 t/ year) but OFC production has dropped.

For the increasing population more and more paddy has to be produced to cut down on import of rice. The death rate has dropped. This may be due to good medical facilities and consumption of low calorie food made out of wheat flour Wheat import was maximum in l995 though paddy production also was maximum Rice import was minimum (9000 x 106 t). In the year 2010 more rice has to be produced to meet the requirement of 216 x 106. At present 500,000 ha of land being cultivated under paddy. This has to be increased or with same, high yielding paddy varieties have to be sown to meet the demand. With the growing population the living conditions of the people have to be improved. The Gross National Product (GNP) per-capita has not changed considerably during the past 24 years. In 1973 and 1997 these values were US $ 230 and US $ 804 respectively. In Japan, Hongkong there is a vast change of GNP. In Japan for the above years these values were US $ 3470 and US $ 38180 respectively. To enable better living standard and high GNP, agricultural and industrial sectors have to be promoted to elevate the income level of the increasing population and to solve the unemployment problem of the youth. For the expected Industrial Development more water is required. To cope up with the demand of the increasing population more energy has to be produced. More people will use electric equipment like washing machines, electric irons, TV sets, and other domestic equipment tl1an today for which they need more electrical energy. The power production from hydro, coal, thermal etc. has to be increased. Hydropower production has reached almost the maximum and there are very few new projects to be taken up. Therefore more of coal and thermal power plants have to be constructed to cater for the increasing base load. At present the base load is being taken by the available hydro power plants. Thereby water is wasted in very large quantities. This water could.be fruitfully used in the dry season for irrigation and for industries, if sufficient thermal power is available. Usually hydropower 10 thermal and coal power should be in the ratio 40: 60. Hydropower should be used only for the peak demand. Hydropower plants could be operated in few minutes to obtain maximum capacity. Thermal power stations take considerable time to operate in full capacity. Hydropower generation in Sri Lanka commenced in 1950 with the commissioning of Laksapana powerhouse, just below the Kehelgamu Oya Maskeli Oya meeting point. Later with the completion of stage II of Laksapana (Laksapana, Wimalasurendra, Polpitiya a11d Canyon power stations), the capacity increased from 25 MW to 235 MW. With the commissioning of power stations in accelerated Mahaweli 660 MW was added from 1985 to 1990. First thermal power station, capacity 22 MW was commissioned in 1962 to supply the power demand during the drought. Later six gas turbines were installed in 1981 to reduce the over dependence 011 hydropower. These operate on diesel. The government has taken action to increase the thermal generating capacity by 2210 MW over a period of 15 years by pursuing other options such as mini hydro wind power and to promote energy efficiency at customers end. The demand for electricity in the country has been growing at an average rate of 7% per annum in the past 20 years. If it is expressed in more simple terms the demand has doubled in every' 10 years. In 1998 the total electricity demand was 5683 GWh, which had been only 2800 GWh tell years back. CEB daily energy demand curve, for 1991,94,98 shows the change in load during a day. The peak demand has gone up from 600 MW to 1050 MW between 1830h and 2300 h. As per CEB the capacity mix over next 15 years is as follows. Installed capacity and the energy requirement from hydro and thermal vary in the following order. In 1999 capacity of Hydro and Thermal are 71% and 29% but in 2013 will be 37% and 63% with the increase of thermal power. This is a very good situation. Thereby enormous quantity of water could be saved operating thermal power for base and operating hydropower for peak. 9.	Rice (paddy) Production The food production increases in this country are dependent to a great extent on development of irrigation schemes. Irrigated lands account for 16% of the world's cropland, meet 40% of food requirement. It is estimated that 1000 t of water is used to produce one ton of harvested grain. Most of d1e 65% of world water accounted for irrigated agriculture is not used by d1e crop. 60% of the water withdrawn from reservoirs, or pumped from underground for irrigation, never reach the crop. This is due to seepage in canals and watercourses and losses in farm channels and) pillage from the field. Inefficient management of water for cultivation of crops and low reliability of water supplies has led to poor performance of many irrigation projects. Optimum duty of irrigation water in a rainy season is 3 to 4 ft/ acre. With the present scarcity of land and water resource the only way available to feed the increasing population is to efficiently use irrigation water. Most of our schemes are not operating at the designed efficiency. That is due to over use of water by the farmers, and also due to losses during the conveyance of water from the source of supply to the paddy fields through canal system. Most schemes need rehabilitation to implement water management and to have the designed area irrigated for both seasons. Water management is to issue farmers right quantity of water at the appropriate time to obtain maximum yields from ii land unit. Water Resources in Minor Irrigation Schemes There are a large number of minor tanks in the intermediate and dry zones. The farmers cultivate paddy under these tanks and chena cultivation and OFC in the homestead blocks. They move from area to area when the paddy fields and chena become unfertile after a few years of cultivation. The cycle is 7 years. This system is unsatisfactory, and is one of the main causes for speedy reduction of forest covers. 10.	Water Management With the completion of a large number of the Irrigation and Power projects in the River basins there is little potential for further development. To meet the future demands of power and irrigation the existing projects have to be more efficiently managed. This could only be done with rehabilitation and implementing Water Management. The project management has to be effective. Both Irrigation Department and Agriculture Department are carrying out Water Management studies to ascertain the correct quantity of water needed taking into consideration of the crop water requirement, conveyance losses in the canal system, seepage in the fields and effective rainfall. By supplying water to the fields in correct quantities at right time, water management is not complete. To complete water management in full the other requirements of the fanners such as implements, loans, insurance, fertilizers, weedicides, pesticides, and marketing facilities, have to be arranged with no time loss. The key organizations have to be alert and kept in readiness to furnish what the farmer need. Most of the fam1ers are growing high yielding short-term paddy varieties, (90 days, 105 days etc.). Growth stages of the plants are very short. Therefore fertilizers, pesticides, weedicides etc. should be applied at the correct date. The water needs be supplied at the right date. By providing every thing except necessary implements, (tractors, spray pumps for weedicides etc.) upsets the whole programmes. For better water management the whole irrigation system has to be perfect in all respect. Water Use in Mahaweli Water management is practiced in Mahaweli areas but it is not promising. They have adopted cultivation of paddy and other field crops to reduce water consumption. Mahaweli project was conceived to meet the demands of staple food, rice. Other field crops with1 low crop water requirement are also cultivated to save water. The prime motive is self-sufficiency in rice. The project was designed with paddy and combination of OFCC those ratios have to be maintained always. 11.	Domestic Water Supply Sri Lanka National Water Supply and Drainage Board is the main supplier of pipe borne water for domestic and industrial use in the entire country. Different industries too have their own water systems. NWS&DB has its own water towers for distributions. The main areas of work are pipe borne water supply, sinking of tube wells, and bug wells. The total requirement for the year 1999 is 600 x 106 m3, Anticipatd water requirement for the year 2005 is 656.5 x 106 m3. By 2010 it is 700 x 106 m3. Presently Board supplies Water to 4.34 million people. The balance population is supplied from rivers, wells, and tanks by their own ways and by Local Government Bodies. Water requirement for monthly domestic consumption is 10.7 x 106 m3. The consumption for commercial establishments is 5.0 x 106 m3. The Board has 380000 domestic connections and 49,000 supply connections to commercial establishments and 9500 stand posts. Proposals for anticipated expansion of water supply system for the next 10 years is as follows. Pipe borne water from 29% to 40%, tube wells from 11% to 15%, wells from 27% to 30% and unprotected wells from 33% to 15%. As tube wells and dug wells have no direct connections with the rivers and reservoirs as majority is situated far away from them there is no abrupt draw down in rivers and reservoir levels. These wells are fed from the ground water recharge or from surface water table. 12.	Productivity For the effective and economical use of water, the productivity of the Institutions and schemes will have to be increased. We are aware that the productivity of the public and private sector in Sri Lanka has dropped to the minimW1l among the Asian countries. Countries like Singapore, Korea Malaysia which were below in GNP compared to that of Sri Lanka in early seventies have now gone above Sri Lanka with a considerable lead. This is due to the low productivity of the working apparatus. The productivity could be defined, as the ratio of output is to input in a Introductive process. This ratio should have a positive value. For service oriented organizations like Departments, Boards and Corporations the efficiency and effectiveness are the two main parameters for increasing productivity The Government declared 1996 as the year of productivity realizing the importance of promoting this programme. Later the decade 1997 to 2006 has been named as "National Productivity Decade" and launched the productivity development programme in the entire country to raise the productivity of the Ministries Departments, Boards and Corporations. Productivity Development Programme could do a lot for saving and economical use of water in the schemes It will streamline the working system in the offices and in field wiping out constraints and delays in the work process. The working environment of the office and field become pleasant with the introduction of Japanese "5S" concept The working staff become close and friendly and find solution to the problems within their reach once the quality circles are form..1. lam very glad to mention that all the organizations under the Ministry of irrigation and Power are jointly taking part in this programme and it is very successful. Irrigation Department is a very large Department with 98 categories of staff with 6000 employees. Their main task is h1vestigation, design, and construction and management of Irrigation, Drainage and Salt water Exclusion Schemes for irrigated agriculture. It is a service- oriented organization. For increasing productivity every employee has to work in an efficient and effective manner. They should have clean and good working environment. With the introduction of Japanese "5S" concept this requirement has been met. The inputs like Men, Materials, Machines, Money, Methods, and Time have to be used efficiently and effectively. This will have o be practiced in the office as well as in the field The irrigation systems have to be very effective and free of losses. Issues should be done at right time in right quantities. For which attitudes of all staff and employees have to be changed gradually It cannot be changed over light. Problem identification and finding out solutions to them should be allowed to the Quality circles formed by the employees under each office or work site. 12.	Conclusion There is enough water available in the country..Most of it gets polluted or wasted in the conveyance process. Pollution is purely due to the discharge of industrial waste into the stream without any treatment. The chemicals and dyes etc. used for Agriculture, industries or hospital waste is being discharged into the streams and major rivers without any concern. No one is bothered about the pollution. It is high time for the Environmental Authority, Municipalities. town councils etc. to take very serious action against those responsible. With the construction of thermal and coal power stations by CEB, there will be enough energy to take the base load. Then most of the hydro power stations will be operated only for the peak load. Enormous quantity of water now used for energy requirement of base load will not be required. It will be used only for the power generation at peak hours. The water saved could be fruitfully used for Irrigation and for future Industrial development to solve the unemployment problem. In most of the irrigation schemes water losses are very high. This is merely due to conveyance losses, over use of water by the farmers, or field losses. These are avoidable losses. These could be minimized. Losses such as evapo-transpiration is unavoidable. Irrigation Department carries out water management in most of the major schemes.
No. of words - 4259
