Author(s): R. W. C. N. Rajapaksha; S. M. C. K. Subasinghe; H. R. L. W. Halgahawatte; W. L. K. Weerasinghe; M. Manoranjan; K. D. W Nandalal; K. Raveenthiran; M. Cassim
Linked Author(s):
Keywords: Hydrological model; Reservoir simulation; Safe yield; Low flow
Abstract: This study is to assess and ensure reliable water resources to meet the long term drinking water demand of the study area up to the horizon of 2040 by exploring and recommending additional water resources if required to bridge the demand gap. MIKE 11 Rainfall Runoff (NAM) and HEC ResS im Reservoir Simulation modelling tools were used in combination to estimate the low flows at existing river intakes and safe yields at impounding reservoirs. Low flow values of the two River basins were estimated using measured flow data and calibrated hydrological models. The existing reservoirs, Labugama and Kalatuwawa were further investigated for their safe yields. The studies reveal that Kalu river has a greater water potential and there is no demand gap exists while low flow values corresponding to 30 year return period daily average in Kelani river shows deficits even for the year 2012 demands. Hence, proposed Upper Wee Oya and Ruecastle potential reservoirs were investigated to have additional raw water sources by the year 2020. However, the main conclusion is that the Kelani river, has the risk of occurring deficits by the year 2025 even corresponding to 2 year return period daily average low flow value.
Year: 2016