Waterfall maintenance of the upper Kotmale hydropower project

Abstract

Sri Lanka's electricity requirement has been growing at an average rate of 8-9% annually, and this trend is expected to continue in the foreseeable future [1]. To meet the high growth rate of demand tor the electricity, more power generating stations should be added to the national grid. Sri Lanka has no fossil fuel resources and therefore implementation of the Upper Kotamale Hydropower Project (UKHP) which uses our indigenous resources is more economical and important for the nation. After several social, environmental and political debates and delays, the construction works of UKHP has now been initiated and the power station will be commissioned in year 2010 [2]. At the implementation of the UKHP the river water of Kotmale Oya win be diverted at Talawakelle intake dam, into the headrace tunnel of length 12.5 km and then to the power house, which is located about 2 km upstream of existing Kotmale reservoir. The significant impact of the project is that the reduction of water flow over the Saint Clair waterfall affecting the natural beauty of the waterfall. Democratic Socialist Republic of Sri Lanka has published a gazette extraordinary making the release of water from the reservoir, to maintain the waterfall compulsory. At the construction phase of the Talawakelle reservoir, a special valve has been proposed to install near bottom outlet of the dam for the purpose of releasing water to maintain the Saint Claire water fall: The objective of this project is to develop an automated system for the optimum water release from the reservoir while meeting the conditions specified in the gazette. Special computer program has been developed to automate the operation of the valve which release water to maintain the waterfall. A graphical user interface was also developed to facilitate the communication between the operator and the controlling system.