Irrigation infrastructure management requirements to ensure water security for impoverished rural populations under climate change scenario

Abstract

Climate change studies have come to maturity with the 4th report of the Intergovernmental panel on Climate Change in 2007. Conclusions about temperature increases, rainfall variations, climate change relationships with evaporation etc., have more or less reached consensus. However climatologists have to fine tune climate models to refine the predictions. It is now necessary to assess the sustainability of the water and its surrounding environment with the anticipated climate changes. As at present in Sri Lanka there is minimum research attempting to link climate change impacts to infrastructure development, and there is none in the area of irrigation. Therefore it is necessary for countries like Sri Lanka where majority of the population depends on irrigated agriculture utilising a large number of small reservoirs, to ascertain the effect on its irrigation systems and identify the adaptation measures that should be implemented. A significant increase of water for irrigation sector would mean pressure on others which compete for water. If water is inadequate for irrigation then it would certainly lead to socio economic issues commencing from the farming community. In order to address these issues and to identify suitable adaptation options, the present research carried out spatially distributed irrigation water demand modelling to assess the administrative district wise requirements in the year 2025. Reservoir water balance modelling was carried out for four selected districts to study the adequacy of minor irrigation reservoirs. Present work describes the modelling efforts that incorporated system deterioration due to lack of maintenance superimposed on the climate changes. The study used irrigation department guidelines, published data and made rational assumptions to quantify the impacts on the irrigation systems. It was revealed that it is necessary for water and related infrastructure managers and engineers to incorporate suitable maintenance programs, and make significant efforts to improve the project efficiencies as climate change adaptation measures.