The island of Kalimantan in northern Indonesia is rich in clean water sources. The east is home to 31 watersheds and has the island’s highest forest cover – 5.2 million hectares. The forest here serves as a catchment area that can replenish rivers and groundwater reserves. A karst region also has an important role to play in ensuring water supplies through springs and underground rivers.
Looking at water supply and quality matters greatly ahead of the move of the capital, which is planned for 2024. The new capital region will cover the three sub-districts of Sepaku, Semboja and Maura Jawa, and researchers predict that as many as six million new residents will eventually move to the city to fill jobs and take advantage of opportunities. But population growth will put pressure on resources like land and water.
The Mahakam River, which runs just north of the new capital’s location in Sepaku subdistrict, currently discharges 5,000 liters of water per second, according to Yohanes Budi Sulistioadi, a lecturer in the forestry department at Mulawarman University. That’s enough to supply 2.88 million people a day if average consumption per person is calculated at 150 liters, as determined by the Ministry of Public Works and Public Housing.
But not all that water is available to the public, nor are plentiful rainwater sources.
Environmental damage caused by deforestation and land clearing for plantations as well as the construction of factories and power plants has polluted rivers across the island, raising concerns not only over whether the new capital will have access to enough water, but whether it will be clean. The Mahakam River’s water quality has been classified as “poor” by the East Kalimantan River Basin Agency III (BBWS Kaltim III).
Land clearing for agriculture and palm oil plantations also causes the soil to compact. As a result, rainwater flows off the surface of the land and is not absorbed into the soil. At the same time, palm plants require lots of water, and the diversion of water for plantations has led to uneven distribution, creating a water crisis in Sepaku.
With the population projected to grow from just over 36,000 people in 2018 to six million by the time the capital is completed in 2024, the water crisis could severely intensify.
So what’s driving this crisis and how can it be mitigated?
Deforestation and land clearing
Between 2013 and 2016, East Kalimantan lost 472,000 hectares of forest cover, according to a 2018 report by Forest Watch, an initiative by the non-profit World Resources Institute to monitor global forests. A push to develop industrial plantation forests for pulp and paper has been largely to blame, with the area covered by such permits increasing from 298,000 hectares in 2009 to 377,000 hectares in 2016. Figures for deforestation across Kalimantan are the highest among all the major islands in Indonesia.
Clearing natural forests increases runoff, leading to higher sedimentation in rivers and dams. A 2018 study by the Ministry of Public Works and Spatial Planning found that East Kalimantan lacks as much as 919 liters of raw water per second due to silting in waterways and the lack of water absorbed by underground aquifers.
Seen as both a response and potential challenge, dams could exacerbate problems associated with deforestation if tree cover is cleared or villages forced to relocate.
The Directorate General of Water Resources of the Ministry of Public Works and Spatial Planning (PUPR), which is responsible for supplying water to the new capital, is planning to construct seven new dams to meet the projected water needs of the new capital. BBWS III estimates that the Sepaku-Semoi dam along the Tengin River will be capable of supplying around 2,530 liters/second (2.53 cubic meters/second ) of water for domestic and industrial needs, flood control and tourism.
But construction of the new dams will need to consider the quality of the catchment area, say conservationists. Tree cover around the edge of catchment areas prevents silt and sedimentation from running into the water. Limiting mining, logging and plantation expansion would also protect water from runoff pollution and contamination – though putting limits on industry has raised concerns among those who make a living from them.
Total catchment area capacity for the new dams has been calculated at 4,100 liters/second during the four-month rainy season. In addition, the East Kalimantan River Basin Agency III (BBWS Kaltim III) plans to improve the efficiency of water distribution from six existing dams in surrounding cities and districts that could bolster the supply available to the new capital. It’s also looking at how to make use of groundwater, wastewater from air-conditioning systems and rainwater harvesting technology.
Rainwater stored in large tanks can be used for building flushing systems or for other purposes, said Chay Asdak, chairman of the National Watershed Forum (pH tests conducted by Kompas show that rainwater collected in the area is slightly acidic and would need to be processed to be safe for drinking).
Chay also advised sourcing groundwater for drinking at a depth of more than 30 meters since groundwater supplies above that depth have tested positive for pyrite or magnesium sulfide compounds that can be harmful to human health, and even treatment doesn’t guarantee that it can be used by residents.
The development of these new dams combined with currently available sources from dams and river intakes would amount to total water availability of 35,482 liters/second across an area of 200,000 hectares, according to calculations by BBWS Kaltim III. It further estimates that the water needs of residents across the new capital area, as well as the five administrative regions the river basin agency covers, will reach 22,990 liters/second by 2024, leaving a surplus of around 12,500 liters/second.
But that estimate only accounts for domestic needs, not those of commercial establishments, government or industries. It’s also just a calculation. The region’s six operating dams currently hold available waters supplies of 4,827 liters/second, but just 48 percent of that supply is utilized due to sedimentation and bureaucratic bottlenecks that prevent water from being distributed. Dams are managed by the central government’s Public Works Ministry, for example, while a regionally owned water company, Cipta Karya, is responsible for distribution.
Another challenge is distribution infrastructure. Many residents in Sepaku sub-district, for example, don’t have access to piped water, forcing them to buy water for drinking and cooking.
The seven new dams and one intake must be fully awake and effectively utilized for water supplies to meet residents’ needs, said Anang Muchlis, chairman of BBWS Kaltim III. If not, the calculation of surplus water demands will become a deficit and still the story of the water deficit will be repeated.
Support for this story was provided as part of a parternship between Internews' Earth Journalism Network and WRI's Resource Watch. This is an updated and revised summary of a four-part story that originally appeared on Kompas in December 2019 titled "Water Carrying Capacity of New Capital Area."
Banner image: Barges transport coal on the Mahakam river in East Kalimantan, Indonesia / Credit: Mokhamad Edliadi/CIFOR via Flickr