Considering future precipitation in delineation locations for water storage systems - Case study Sri Lanka

Abstract: Demand for the usable water is accumulating globally in parallel with the population growth and the industrial revolution. Nevertheless, availability and accessibility of the usable water is progressively subsiding due to many environmental and socio-economic reasons. This discrepancy can lead the world to a water crisis unless it takes necessary actions to enhance the sustainable use of existing water while maximizing the water storage capacities for the future use. Having said that, paying less attention to the highly related factors while implementing new water related projects, does not seem supportive in achieving their goals. This paper intends emphasizing the importance of consideration of the expected changes in the associated environmental and socio-economic factors in the long run when locating water storage systems. Although this study has been limited to the consideration of the precipitation factor, the methodology used in this paper is compatible with utilizing the expected variations in other related climatic factors. The project focuses on Sri Lanka. Having a year-round rainfall, the country has still been incapable of fulfilling the annual water requirement of the population. Adding new water storage systems focusing on maximizing the rainwater harvesting by taking the future precipitation pattern into account, is considered as one of the effective solutions to tackle the issue. This study focuses on delineate locations for terrestrial water storage systems by taking the future precipitation pattern in the year 2050 into consideration. Despite delineating new locations for water storage systems, the study also points out the available water features within the country that are vulnerable to be dried out in the future mainly due to the change of precipitating pattern. Other related geographical, environmental, and socio-economic factors are integrated with the future predicted precipitation data in delineating the results. Thresholds and weighted linear combination methods were utilized in prioritizing the related conditions at the primary location selection. Pairwise comparison method was utilized in assigning the weights. Additionally, the GIS framework introduced in the paper can be applied to any geographical location based on the availability of data.