Jakarta – Concerned that the embankments containing the Sidoarjo mudflow might burst during the rainy season, the team overseeing the East Java disaster area has opened a spillway, a canal to divert the mud into the nearby Porong river.
The spillway is expected to divert around 864,000 cubic meters of mud each day. The flow from the botched Lapindo gas exploration well site has been increasing since it started in May this year.
"The spillway has been operating since 6 p.m. on Friday. The results have been great as the depth of the mud inside the pool has tremendously decreased," said national team director Basuki Hadimuljono on Saturday. "Unlike the pumps, the spillway is working 24 hours a day," he said.
Basuki told The Jakarta Post that the team had been working on the canal since Sept. 8. Around 100 people have worked day and night to finish the 600 meter long and 15 meter wide canal.
"We chose the spot with the lowest topography so all the mud will flow to the area. Afterward, we selected contractor PT Adhi Karya, a state-owned company, to construct it," Basuki said.
The spillway includes a filter that separates garbage and waste from the mud before it is mixed with water. Three pipes at the end of the canal then pump the mud into the Porong River. The spillway's floor is covered with plastic to prevent underground leaks.
"To prevent sedimentation, we plan to dig sand out of the river's mouth before the rainy season comes. Our calculation shows that we should dig the sand to about 45 meter in depth and 40 meters in length," Basuki said.
The spillway, like the Porong River, faces the constant threat of sedimentation, which could cause an overflow. "We will use dredges and clamp shells to dig and send the mud to the Madura Straits. The Maritime Affairs and Fisheries Ministry will assist us in the process," Basuki said.
The gushing mudflow has submerged four villages and left 12,000 people homeless.
Basuki said the local community has been awed by the spillway's reduction of the volume of mud. "Many locals gathered near the spillway and stayed there until Friday evening. I think they felt a sort of relief by looking at the decreased volume of mud inside the pond," he said.
Not everyone, however, is satisfied with this solution. Indonesian Forum for the Environment executive director Chalid Muhammad told the Post that the dumping of the mud into the river and ocean carried an invisible ecological threat.
"Digging up the sand to avoid sedimentation does not solve the problem, as the massive volume of mud could still badly affect the environment," Chalid said, adding that the government had only one provided one solution to the problem.
"(Such a) massive volume of mud has the potential to ruin the hydrological system and the metals in the mud could reduce the output of fishing products, such as organic shrimp, on the coast," he said.