10th International Rainwater Catchment Systems Conference
"Rainwater International 2001"
Mannheim, Germany - September 2001

Section 2: Rainwater Catchment in Humid and Arid Regions

Paper 2.5

M.M.M. Aheeyar
Hector Kobbekaduwa Agrarian Research and Training Institute
Colombo
Sri Lanka
email: hartiiar@sltnet.lk

Introduction

Although Sri Lanka's climate is in the Monsoon zone and therefore with ample water resource in its wet zones, recent studies show that there are wide temporal and spatial variations of water availability and demand. If the current trend of water use efficiency continues, there will be a severe scarcity of water in several districts of the country in the near future (Amarasinghe et. al, 1999). In addition, 43% percent of rural population are deprived of safe water for drinking purpose (UNDP, 2000). Scarcity in water availability will be more aggravated with the economic development and implementation of free market policies, where demand for water for industries and domestic use will increase. Therefore the envisaged water crisis will be a significant constraint for the country's socio-economic development.

The community Water Supply and Sanitation Project (CWSSP) was an innovative project started in 1993 and aiming to establish an alternative system of water supply and sanitation delivery in rural Sri Lanka. The project was implemented based on the needs and aspirations of the people though community initiated projects. The project mainly used the following technologies to achieve domestic water security at household level. These include, Gravity Water Supply Systems, shallow dug wells, hand pumps/bore holes and pumped pipe systems. However, these conventional technologies were not suitable to supply safe water for the communities living in uphill settlements. In hilly areas the ground water table is very deep and most springs and wells dry out quickly during the dry season. In addition to the uphill areas, some places in the dry zone of Sri Lanka also have water problems for domestic use, particularly those areas where groundwater sources are not reliable throughout the year and the available water has problems of salinity, hardness and high concentration of other elements.

A technology for systematic rainwater harvesting (RWH) was proposed and successfully implemented in the uphill areas and dry zone of Sri Lanka by CWSSP with community participation and contribution. The difficulties and time involved in fetching water, uncertainty in available water, rising costs in water fetching and low quality of available water sources provided a greater incentive to beneficiaries to adopt rainwater harvesting technology. The main components of the rainwater harvesting systems are catchment surface for water collection (mainly domestic roof), gutter system for water delivery and a tank for water storage. Although Sri Lanka is a country with an annual average annual rainfall of nearly 2000mm, spatial and temporal variations in rainfall make it necessary to adopt a technology for systematic collection of rainwater.

PDF of full document available to members (5pp, 24kb)