Indonesia: Dams closed; people use seawater due to dry season

Ganug Nugroho Adi, The Jakarta Post 7 Oct 15;

The prolonged dry season has forced authorities to close the Gajah Mungkur and Colo dams in Central Java and hundreds of families to use seawater in West Nusa Tenggara (NTB) for their daily needs.

Head of the water resources and water services division of tap water company Perum Jasa Tirta’s (PJT) I Bengawan Solo River region, Winarno Susiladi, said the current elevation of Gajah Mungkur, one of the biggest dams in the country, was 129.39 centimeters and its water level had yet to increase because the stream in upper areas was not yet filled with water due to the prolonged dry season.

With such a volume, the turbine of Gajah Mungkur’s hydropower plant could not operate since the minimum water debit required for the turbine to work is 19 cubic meters per second.

“The water volume indeed is not sufficient to move the turbine, but we have no problem with electricity as the electricity network in Wonogiri is also connected to other regions,” Winarno said on Tuesday.

In normal conditions the electricity produced can reach up to three megawatts per second, he said.

He added that the decrease in the volume of the dams had also caused a decrease in the clean water supply from Wonogiri tap water company (PDAM) Giri Tirta Sari.

To deal with the problem, said Winarno, the company dammed up the Bengawan Solo River in Sanggrahan, Giripurwo.

“We apologize if the water supply from the company is disrupted. We are trying to increase the debit by damming up river,” Giri Tirta Sari’s president director Sumarjo said.

Doing so, according to Sumarjo, could increase the water debit. He said the measure had been taken for years by his company, especially during dry seasons when the water debit decreased.

PDAM Giri Tirta Sari currently services some 8,000 customers.

However, the Bengawan Solo River Management Agency (BBSBS) said that it had closed the water gates of the Gajah Mungkur and Colo dams, located in Wonogiri and Sukoharjo respectively, for the whole month for maintenance.

Closures were also effective on the dams’ irrigation canals, stopping water from flowing to some 23,000 hectares of rice fields.

“The closure will not influence the plants in the fields as most of the rice is about to be harvested. We have disseminated information to farmers,” the agency’s maintenance division head Danang Baskoro said.

Danang said the closures were an annual occurrence to maintain and repair the dams as well as their irrigation canals and water gates.

Separately, Wardiyono, a farmer in Sukoharjo, said the closure of Colo Dam would influence some 5 hectares of rice fields in the regency. He said not all rice plants in the region were ready for harvest.

“But, what else can we do? It’s time to close the dam. I can only surrender,” said the 54-year-old farmer.

Meanwhile, in NTB, some 500 families in Doro O’O subdistrict, Langgudu district, Bima regency, were reportedly forced to use seawater for their needs.

“It’s because no water is left that people were forced to drink from the sea,” NTB provincial councilor Misfalah said in Mataram on Tuesday as quoted by Antara news agency.

Misfalah said that water scarcity had begun since drought had hit the region. Springs and people’s wells have also dried up.

“If they want to get water they have to walk for 10 kilometers, not to mention the location of the water sources on the hill and seawater entering water sources and wells,” Misfalah said.