Tuesday, October 10, 2006

Environmental Impacts of The Proposed Baddegedara Impounding Reservoir

N. Ratnayake and P.Y.D. De Silva
Department of Civil Engineering,
University of Moratuwa.

The alternative sources of water available for the consumers in the project area covering Talpe, Habaraduwa, Koggala EPZ and coastal belt, Ahangama, Dikkumbura and Imaduwa are ground water, or surface water from Gin ganga, Nilwala ganga or the proposed impounding at Baddegedara.

The first choice on the basis of water quality and treatment costs was ground water, but after a test drilling program this source was found to be inadequate.

The proposed impounding reservoir at Baddegedara is located near to the project area and technical feasibility studies revealed that this is a feasible proposal.

Positive and negative environmental impacts of the proposed project were identified using an environmental interaction matrix and it was attempted to evaluate the overall impact using the Battelle's Environmental Evaluation System. Weights for the different impacts were assigned depending on the relative importance of the impacts. Value functions for some of the impacts were developed.

The topography of the area does not lend itself to the fashioning of a deep lake. According to past studies, it has been showed that the ideal wild life lake is shallow with gently sloping shores. This type of situation could he expected from the proposed impoundment. These natural qualities of the habitat could be further augmented by various management techniques such as the restriction of the area of impoundment and catchment.

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