Dam Safety ＆ Water Resources Planning Project in Sri Lanka-Special Consideration on Rockfill Dams
摘要：＜正＞The dam network of Sri Lanka comprises over 350 medium ＆ large dams and over 12,000 small dams.Most of the dams are aging and suffering various structural difficencies and shortcommings in operation and monitoirng facilities.Therefore,to overcome these challenges the Dam Safety Water Resource Planning Project（DSWRRP） initiated in August 2008 with the financial assistance of World Bank.The project objective is to improve the development and management of water resources within the country,reduce water induced hazards to public,and enhance effectiveness of water related investments. The dam construction ＆ development in Sri Lanka would be divided into two eras such as ancient dams which were build in several hundred years ago by the ancient kings and modern concrete large dams build with the Accelerated Mahaweli Development Programme after 1970s’.There are four types of dam categories in Sri Lanka namely:homogeneous earth fill dams,rockfill dams,concrete gravity dams and concrete arch dams.There are three rockfill dams out of the five dams which constructed under the Accelerated Mahaweli Development Progrmme namely;Kotmale,Randenigala and Maduru Oya.The other two are concrete gravity ＆ concrete arch type namely:Rantambe and Victoria. Kotmale dam was constructed in 1985.Special feature of this rockfill dam is,it consist of upstream concrete membrane.Main purpose of this dam is hydropower generation ＆ Irrigation.Randenigala is the largest multipurpose reservoir which was constructed in 1986.The dam comprises a rockfill embankment with a central clay core Maduru Oya dam commissioned in 1984 with the purpose of irrigation. It is an earth core type rockfill dam.Nevertheless,ancient bund and sluice of Maduru Oya was found on the new dam axis when site clearance was done for the new dam.According to the available records ancient dam and sluice constructed in 9th century,discovered in 1978 and considered as an engineering marvel.The second largest project after the Mahaweli is the Samanalawewa hydroelectric project.Samanalawewa is a rockfill earth core type embankment dam.Samanalawewa dam was commissioned in 1992. This paper describes the rockfill dams in Sri Lanka and their current structural deficiencies and remedial actions which will be carried out by the DSWRPP.Rehabilitation of these dams would be scheduled by DSWRPP to mitigate risk to the human lives,public ＆ private property by mitigating social ＆ environmental effects in sustainable manner.