High Sedimentation Threatens Jatigede Reservoir
550 metre-long tunnel starts to be built
Sumedang - Ministry of Public Works (PU) has made an assessment that Jatigede Reservoir in Sumedang, West Java, will have a short lifespan of just 50 years if a greening initiative is not undertaken in the area around Cimanuk River.
Public Works (PU) Minister Djoko Kirmanto said that, according to calculations, the rate of sedimentation in Jatigede Reservoir has reached 5.32 millimetres per year or 7.77 million m3 per year, so that the utilisation lifespan of Jatigede Reservoir will only be 50 years.
"A solution needs to be found to deal with the impact of the high sedimentation by promoting conservation activities in the watershed area (DAS) of Cimanuk River intensively and synergically between the Ministry of Public Works, Ministry of Forestry, West Java Provincial Government and the relevant regency governments," said Djoko, in Sumedang, Wednesday (3 August).
To reduce sedimentation, according to Djoko, in addition to the greening programme in the area of Cimanuk River, a cekdam (levee to prevent river from widening) in upper area of the Reservoir will be made. Thus, sedimentation can be lifted and will not get into the Reservoir. "All the effort is intended to make the utilisation lifespan of Jatigede Reservoir longer," he said.
Djoko asserted that conservation of water resources, especially in the upper reaches, should receive more attention, in order to maintain good conditions of the environment. The better the conditions of the headwaters, the better they will ensure the sustainability of the reservoir’s benefits. Jatigede Reservoir has now entered the stage of core work, namely damming up Cimanuk River.
Djoko explained that redirecting the water flow of Cimanuk River through a diversion tunnel in the Jatigede Reservoir construction project marks the commencement of backfilling activities along Cimanuk River path.
According to Djoko, the society has long been waiting for the availability of Jatigede Reservoir. Starting with the study phase on the Cimanuk River - Cisanggarung River area in 1963 by Coyne et Bellier consultants of France, which recommended the need for a multipurpose dam built to support the development of the region, ensure availability of water for the Rentang irrigation (system), which was built in 1917 and covering more than 90,000ha, control flooding in Cirebon - Indramayu areas in Pantura route, and providing electricity through hydropower plant (PLTA).
Jatigede Reservoir is built using the type of uprightly stacked core stones, with a levee height of 110m and volume of stacked stones reaching 6.7 million m3. Then, a 550m-long evader tunnel having a diameter of 10m has also been built, with its ground breaking taking place in October 2008.
Djoko mentioned that Jatigede Reservoir has a water storage capacity of 980 million m3, or nearly 1 billion m3. Jatigede Reservoir will in due course become the second largest dam in Indonesia after Jatiluhur Reservoir (with a capacity of over 2.5 billion m3) in Purwakarta.
Functionally, Jatigede Reservoir offers considerable benefits. In addition to improving the welfare of the community, it also supports national food security and supports the efforts to increase agricultural production through the provision of water to irrigate agricultural land areas of more than 90 thousand hectares. The Reservoir can also function as a provider of raw water, water recreation, and an 110MW power plant.
Therefore, the PU Minister has requested the Provincial Government of West Java and Sumedang Regency to immediately prepare a Master Plan for tourism development of Jatigede Reservoir.
Cimanuk Flow Diversion
On that occasion, the Minister of PU also inaugurated the diversion of Cimanuk River flow into the Evader Channel to signify the functioning of the channel and the commencement of the stage of backfilling into the body of the dam. Thus, dam construction can be completed on time, i.e. in 2013. "If it is late, its completion will be in early 2014, when the dam will have become functional," said Djoko.
West Java Governor Akhmad Heriawan added that the provincial government has been conducting socialisation to residents regarding the land acquisition process, including finding alternative resettlements for those residents who will be evicted.
West Java Provincial Government this year has provided funds from its budget to the amount of Rp 21 billion and in 2012 to the value of Rp 36 billion to free up 146ha of land. "Until this year the total land has been acquired has reached 126.44 ha," said Heriawan. (imm)