0 Flood Tunnel ‘Could Double As New Clean Water Source’

The massive tunnel project that the Jakarta administration has proposed as a way of preventing flooding in the capital could also be used to ensure a steady supply of clean water to city residents, an observer has suggested. Firdaus Ali, an expert in urban water management at the University of Indonesia, said on Sunday that the so-called Deep Tunnel, which is expected to channel rainwater runoff from the city center out to sea, could also be used to complement the city’s piped water network. 

“The supply of clean piped water to residents remains relatively low,” he said, noting that the two private water operators responsible for the supplies currently only served a combined 44 percent of households in Jakarta. “This has resulted in a pretty serious water resource management problem, which is the unregulated exploitation of groundwater reserves, which in turn is leading to land subsidence in several areas, and consequently to seawater contamination of the groundwater.” 

Firdaus said a viable solution would be the deep tunnel, which he argued could also be seen as a reservoir for rainwater. Once the rainwater is processed, he went on, it could supply clean water at a total rate of 4,000 to 12,000 liters per minute. The proposed tunnel, estimated to cost Rp 16 trillion to build, will run 22 kilometers at a depth of 40 meters, and will consist of three channels. The upper two channels will be for traffic, while the lowest one will be used to channel away rainwater runoff and carry utility piping. 

The road portion of the tunnel will not run the entire length, but will stretch a distance of 10 kilometers from M.T. Haryono in East Jakarta to Slipi in West Jakarta, according to city officials. The drainage channel will empty out into Jakarta Bay. Planned entry and exit points for vehicles will be located in the Gatot Subroto area to accommodate traffic coming from the Warung Buncit and Mampang areas, as well as Tomang and Slipi Jaya. 

Jakarta Governor Joko Widodo has touted the tunnel as a necessary breakthrough to address the twin problems of flooding and traffic congestion in the city. Firdaus, a member of the regulatory board overseeing the city’s water operators, said the tunnel would be ideal for addressing the clean water shortage. He pointed out that none of the 13 rivers running through Jakarta was clean enough to use as a source of piped water, while growing demand was putting a strain on the city’s primary source of clean water, the Jatiluhur reservoir in Bekasi. 

Herawati Prasetyo, a deputy director of PAM Lyonnaise Jaya (Palyja), one of the city’s two private water operators, acknowledged that with the company getting 61 percent of its water from Jatiluhur, it was highly dependent on conditions at the reservoir to ensure a reliable supply of piped water. “Palyja’s supply of raw water is very dependent on Jatiluhur, so if the water level there goes down, then the volume of water that we get also goes down,” she said.

source : the jakarta globe