Water for rural development

22nd March is International Water Day and this article highlights the importance of water in rural development

By Dr. C.S. Weeraratna

(March 21, Colomno, Sri Lanka Guardian) The rural sector which constitutes around 80% of the population of Sri Lanka plays a very important role in our economy. This sector is responsible for the cultivation of around 2 million small holdings with an average holding size of approximately 1 hectare. Almost all the food crops such as rice and other cereals, legumes, field crops, fruits, and livestock produced in the country, valued at around Rs. 100 billion, come from the rural sector. The main source of income of nearly 90 % of the rural population is agriculture and animal husbandry. Hence, any attempt to develop the economy of the country needs to take cognizance of this sector.

The main strategy to develop the economy of the rural sector is to reduce poverty by implementing an integrated development programme. Agriculture and livestock are the important sectors which have to be given priority in our endeavours to revitalize/improve the rural sector, mainly because there is a considerable potential for development of these two sectors. It will bring about numerous social benefits, increase our food security situation, make food cheaper resulting in higher calorie intake and better nutrition level, reduce the expenditure on food, and increase employment opportunities.

Most of those in the rural sector depend on rain not only for their various domestic activities but also for earning a living. Their main sources of income such as agriculture, livestock production and inland fisheries are rain dependent. Freshwater availability is a key limiting factor in food production and other livelihood improvement in the rural sector. With increase in pressures of population growth, development aspirations, water is increasingly playing a key factor in socio-economic development. This will require an effective integrated management of water resources.

Water Resources of Sri Lanka:

In Sri Lanka, rainfall is the primary source of water. The mean annual rainfall is around 1800 mm with areas such as Hambanthota and Mannar receiving about 900 mm and some areas in the hill country receiving about 5,000 mm. The total amount of water the country receives annually from rain is around 100 billion cubic meters. Out of this around 40% runs-off. A total catchment area of nearly 60,000 sq. km., each varying from 10-10,000 sq. km , catches the run-off water emptying it to 103 rivers and major reservoirs and the tanks in the country. Water thus collected (around 35% of the run-off) is used for irrigation and generation of hydro-power and the balance i.e about 65% of the run-off escapes to the sea. Thus, nearly 26 billion cubic meters of water is wasted.

The main source of water for irrigation in most of the dry zone areas is river diversions and reservoirs ( tanks). There are around 12,000 small tanks distributed across the undulating landscape in the dry zone. These tanks are not randomly located but occur in the form of distinct cascades each made up of 4-10 small tanks situated with in a single small catchments (meso-catchment) varying in extent from 100-1000 ha, and impound surface relief water of a watershed for irrigation and domestic purposes. These small tanks are concentrated in the dry zone. In the past, these tanks were an integral part of the eco-system and played a dominant role in the socio-economic and cultural aspects of the village leading to a prosperous rural sector by providing irrigation to about 185,000 ha. However, cultivable extent from these small tanks have decreased gradually with siltation . Due to low rainfall during Yala season there is hardly any water in these tanks and hence cannot supply any appreciable amount of irrigation water during this season.

Recently, the Government initiated the Moragahakanda Development Project in north-central Province. This is a multipurpose water resources development scheme which will provide increased water supplies to about 81,500 ha of drought-prone areas in the northern and central parts of Sri Lanka. The project would involve construction of dams with a total crest length of around 1,200 m on the Amban Ganga tributary, forming a reservoir of 570 million cubic meters capacity. The Project will also supply potable and industrial water to major towns and incorporate a hydropower station with an installed capacity of about 20 MW.

Cultivation of crops with direct rain (rain-fed cropping) is common in many parts of the country. In the Dry Zone rain fed cropping is practiced mainly during Maha season. These farmers are at a risk, as if rain fails their crops will be affected. In the last few years, in the Dry Zone, agrowells have been constructed under numerous tanks. These are used to lift irrigate high value cash crops during the off season, which enable farmers to earn higher profits. Agrowells are supplied by ground water which is limited. Hence, extensive use of ground water would result in development of saline soils.

Effective use of water : Lack of a regular and dependable water supply to increase the area and intensity of cultivation is a major limiting factor in our attempts to develop the rural sector. From the total rainfall, around 25% of rain water is lost in the form of surface run-off and conserving this water will promote crop growth in areas where water is limiting. The most effective and economical method of conserving this water is storing it in surface tanks which are abundant in the Dry Zone. However, most of the small tanks are dilapidated and/or silted and needs rehabilitation.

If the run-off water is stored in the land itself, it would be available to plants when there is water shortage. In some parts of the dry zone, small ponds called "Pathahas" have been used to collect and store rain water. Such a water collecting system on farm would enable farmers to cultivate crops during the dry seasons. It also tends to increase the ground water level, thereby making plant growth possible even during the dry season.

As indicated elsewhere, a considerable portion of the rainwater runs-off, which tends to erode soils resulting in degradation of the land. Aappropriate soil/water conservation measures such as contour drains/bunds, to retain this water in the land itself would reduce land degradation and promote crop production.

Collection of rainwater, commonly called rainwater harvesting is another effective method of conserving rain. water . Water that falls on to the roofs of houses and other buildings can be collected in appropriate tanks for use . Rainwater harvesting is practiced in many countries including Sri Lanka. By Rainwater Harvesting in urban areas a substantial amount of water can be collected to be used for various domestic activities thereby saving chlorinated water. Various forms of tanks can be used to collect rainwater. More information on rainwater harvesting can be obtained from the Lanka Rainwater Harvesting Forum at Subadrarama Lane, Nugegoda, (Tel. 2820815)

Water Quality

Water quality is closely linked to water use and to the state of economic development and has been heavily impacted by industrial and agricultural chemicals. Water supply for various sectors of society is getting increasingly complicated as water contamination escalates, and awareness grows among water users of the links between upstream polluters of water with downstream water users. Microbial contamination of surface water cause serious health problems. Eutrophication of surface waters from human and agricultural wastes and nitrification of groundwater from fertilizers tend to affect the quality of water. A large number of people in some parts of the Dry Zone of the country are affected by a Chronic Kidney Failure attributed to cadmium/ pesticides in drinking water. High levels on fluoride in water in some parts of Sri Lanka result in fluorosis. Factory effluents also tend to pollute water. Unless appropriate measures are taken to control water pollution the problem of water scarcity will aggravate.

Integrated Water management

There is a need for a broadened approach to water use as populations grow in regions where water is limiting. Water waste in crop production need to be looked into with implementing appropriate measures to reduce such wastes. Although a crop of paddy needs only 4-5 acre feet of water, farmers in some paddy growing areas use as much 6-7 acres feet of water. In such areas, it is essential that farmer education programmes are conducted to reduce water consumption.

Projected increases in water withdrawal may cause the ecosystem to collapse. Similar problems exist with land degradation. An appreciable extent of agricultural lands are degraded, and drought and desertification threaten the livelihoods of people inhabiting these areas. Further, there is a risk that the low attention paid to water pollution abatement together with the projected increases in water withdrawal and use will exacerbate the water pollution problem.

It is extremely important to realize that the water requirements will involve a continuously growing competition for this resource, and the deterioration of water quality has to be actively abated. A new perspective on water resource management for rural development with the involvement of the rural community adds new dimensions to an Integrated Water Resources Management.

(The author of this article is the former Professor of Soils and Water Resources Management of Rajarata University and presently Chairman of Sugarcane Research Institute)

-Sri Lanka Guardian