Intervention of the Dam Safety and Water Resource Planning Project (DSWRPP) in renovation, rehabilitation and modernization of the large dams of Sri Lanka has greatly improved the safety of the dams and efficiency of the major irrigation systems of the county supporting the growth of the agriculture sector. Renovation of 31 main reservoirs has been completed in the phase -I of the project started in 2008 and ended in 2014. Another 32 dams are now being renovated under the DSWRPP (Additional Finance) Project started in 2014. The renovation work is now under way achieving expected targets and the project will be ended in mid-2018.
The greatness of the irrigation systems in Sri Lanka is a consequence of the greatest engineering skill exhibited in the ancient Sinhalese Kingdom. The progressive building up of a huge and complex system of interrelated dams, canals and tank cascade systems to mingling the water of rivers flowing in different directions are notable achievements in water management in our history.
As a result of destructions by South Indian invaders and abandoning during the colonial rule over 400 years, this irrigation system and the associated civilization was ruined. In the post-colonial era from the independence from the British in 1948 again the economic development of the country is centred on this ancient irrigation system. Ancient tanks and irrigation systems were renovated and farmer colonies were started. Following the ancestors the first government of independent Sri Lanka further expanded this irrigation network and in 1949 Galoya dam was initiated. Again in 1970s Mahaweli Development Scheme was designed with the same objective of boosting the agriculture sector of the economy as well as generating hydroelectricity for the industrial development.
Loss of water storage capacity
Over the time these ancient hydraulic structures as well as reservoir dams built in recent past were facing with interdependent challenges due to aging of structures, suffering from various structural deficiencies and shortcomings of operation and maintenance of such structures. This situation threatens public safety of downstream lives and also affects the operational efficiency of the dams and appurtenances. Failure of a dam structure or emergency spillway operation, could lead to disaster which resulting hazards including physical damages, loss of life, as well as long term economic losses associated with loss of water storage capacity for many users. Therefore, dam structures and reservoirs demand both regulatory and operational safety measures and timely remedial repairs. The need of immediate remedial measures and comprehensive rehabilitation of these dams was emphasized after the disaster caused by the collapse of Kanthale dam in 1986.
On the other hand the National Hydro-meteorological data collection, storage and management were done in fragmented way without having linked with databases managed by different stakeholders. Such databases were outdated, inadequate and inappropriate for modern-day water resource planning, flood forecasting and management. Therefore, dedicated Hydro-meteorological Management Information System (HMIS) had to be established by integrating and networking of prevailed operative units by improving and upgrading their capacities and also introducing fully equipped existing and new units.
With the increasing population demand for water is increasing and now the main challenge the dam owners have been faced is the catering these increasing and competing demand for water. Today water in main reservoirs is used for several purposes; for hydro electricity generation, irrigation, drinking water supply, industrial usage etc. In a situation of growing urban and rural demand for water, competition for water among different uses is immensely increased. This emphasized an urgent need to manage and allocate the country's water resources efficiently and effectively by adopting sector wide approach to swapping individual interests to maximize shared management of water resources.
In 2008 government started DSWRPP to addresses the above challenges by undertaking remedial works of critical dams, provision of basic safety facilities, upgrading hydro-meteorological data collection, storage, management and dissemination system, enhancing capacity of institutions involved in the water sector to acquire knowledge and skills in using modern analytical tools and management practices to undertake sustainable multi-sector planning, development and management of the water resources in the country.
In addition, project assists to reviewing and exploring the development potential and feasibility of existing water resources plans, including revised Mahaweli Water Resources Development Plan.
Accordingly 32 high risk dams out of 80 large dams were identified to be fully renovated under the phase I of the project. Basic facilities for efficient operations and maintenance were provided for all 80 large dams including 32 dams. By the end of 2015, out of the 32 dams renovation of 28 dams had been fully completed and the physical progress of the project was 93%.
Disaster management agencies
DSWRPP also invested money for the establishment of modern HMIS system. The large reservoirs are also playing an important role in flood control as they hold large volume of water. Therefore in the flood risk assessment water levels of the reservoirs is also an important data. HMIS stations have been set up in all major reservoir and now the disaster management agencies can receive all these data real time through modern automated measuring system. Therefore HMIS is one of the important component of the DSWRPP.
Dam owners of Sri Lanka, Irrigation Department (ID), Mahaweli Authority of Sri Lanka (MASL), Ceylon Electricity Board (CEB) and Water Supply & Drainage Board (WSDB) are joined hands to implement the project together with other stakeholders involved in the water sector. Emphasis is given to safeguard the Social and environment aspects in the rehabilitation process of dams together with due consideration on protection of cultural properties of the dams. The Total project cost of the Phase I of the project was US$ 71.66 million which was shared by US$ 6.33 from GOSL and US$ 65.33 million from the World Bank.
With the success of the phase I of the project the government decided to extend the project to cover other high risk dams out of 80 major dams and the World Bank agreed for additional financing. In 2014 another 31 dams were selected for renovation with continuation of water sector development and estimated project cost was US$ 83 million. The rehabilitation of 31 dams is now underway under the direct supervision of Implementation Agencies (ID, MASL, CEB, and WSDB).
Rehabilitation work of Periyapandivirichan dam in the Mannar district and Mahakanadarawa dam in the Anuradhapura district have been fully completed and the progress of the whole project is impressive.
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