Impact of irrigation on drinking water availability in Sri Lanka

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IDL-54494.pdf (9.51 MB)

Date

2002

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Abstract

In the Uda Walawe irrigation system in the dry zone of southern Sri Lanka, residents have dug shallow wells for domestic water supply next to canals. Several of these shallow wells, and nearby tube wells as well as the surface water were sampled for water quality testing. Reservoirs and canals had higher levels of bacteria and parasites than shallow wells and tube wells. Salinity and fluoride levels were highest in tube wells. Combining the four indicators, shallow wells offer the best quality for drinking water and are preferred by the population because of taste, availability, easy access and reliability. This most favorable domestic water supply turns out to be highly dependent on irrigation water management. Some wells fall dry between cropping seasons, which suggests that groundwater in the wells is recharged by seepage from irrigation canals. This is confirmed by detailed groundwater measurements and calculations. Water levels were measured in shallow wells and piezometers at varying distances from the canals, before and after lining. Groundwater levels closely followed changes in canal water releases and canal seepage accounted for 74% of groundwater recharge. After concrete lining of the canals, people in this rural area are facing increasingly restricted availability of good quality water. Consequently, the irrigation rehabilitation program is threatening the most favorable source of domestic water and with it the health of the population. This study clearly indicates the need for inter-sectoral planning and management of water resources. More efficient irrigation management does not serve the rural population if it deprives them off their best source of drinking water.

Description

Meeting: International Commission on Irrigation and Drainage : Eighteenth Congress, Montreal, Canada, 2002
Includes abstract in French

Keywords

IRRIGATION SYSTEMS, IRRIGATION CANALS, TUBE WELLS, WATER QUALITY, SALINIZATION, WATER MANAGEMENT, GROUNDWATER, RURAL COMMUNITIES, DRINKING WATER, AGROECOLOGY

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http://hdl.handle.net/10625/54494
 http://slwater.iwmi.org/sites/default/files/DocumentRoot/H_36031.pdf

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Collections

IDRC Research Results / Résultats de recherches du CRDI
2000-2009 / Années 2000-2009
Research Results (Ecohealth) / Résultats de recherches (Écosanté)