Koran Tempo, Hendrik Yaputra, Penajam – Sepaku district, ring one area or the central government hub in the new capital city of Nusantara, was hit by flooding on Friday, March 17.
Roads, houses, and rice fields that were ready to be harvested were inundated. A resident named Pandi, whose house is located approximately 1 kilometer from the zero point of the IKN and close to the upstream of the Sepaku River, claimed that rain did not drench the area on Thursday night.
The 50-year-old man said his house area is prone to flooding every year. Floods occur one to two times a year. However, he said, the floods receded more slowly since the construction of the IKN project commenced. "The floodwater level keeps rising until the afternoon," said Pandi, who is the indigenous people of Suku Balik.
The Regional Disaster Management Agency (BPBD) of North Penajam Paser Regency confirmed that floods had hit three neighborhood units or RT in Sepaku Village due to the overflow of the Sepaku River following high-intensity rains in the upstream area. Residential houses in the low zones and around the river banks were inundated.
RT 03 Sepaku area was the worst affected by the floods. At least 20 houses were inundated with a water level of 40-50 centimeters. BPBD noted that from 2019 to January 2022, floods had 15 times hit several Sepaku areas; in Sukaraja Village, Karang Jinawi, Binuang, Sepaku Sub-District, and Pemaluan Sub-District.
Jubain, head of the Indigenous Balik Tribe in the Pemaluan Sub-District, said the Thursday's floods in his area were the worst since 2010. "Perhaps the height could reach 1.5 meters," he said.
He suspected that the floods occurred due to the activities of industrial forest concession (HTI) companies in the river upstream. "They destroy our forest," said Jubain.
Sibukdin, the head of the Indigenous Balik Tribe in Sepaku village, said floods have occurred since the exploitation of land in the upstream area of the Sepaku River in the 1960s causing the river to be shallow and narrow. "Since then, this area is often hit by floods every two to three years," he said.
According to him, the flooding in Sepaku was exacerbated by the IKN project construction. The floods have also receded longer since then. He assessed that it was because of the building of the Sepaku River Intake prepared as a raw water supply for the IKN. The project location is adjacent to the residents' rice fields.
Based on the National Mining Advocacy Network (Jatam) data, the ring one area of IKN reaches 180,965 hectares. The areas have 162 mining concessions, HTI companies, companies that own forest concession rights (HPH), oil palm plantations, coal-fired power plant projects, and property areas. As many as 158 of the 162 concessions were coal pits which still left 94 gaping mine pits.
Endemic trees replaced with industrial plants
Pradarma Rupang, a researcher from East Kalimantan Jatam, said Sepaku District as the core area of the IKN has a high threat of flooding. He explained that heavy-intensity rains always lead to flooding in the first ring area of the IKN, namely Sukaraja, Sepaku, Bumi Harapan, and Pemaluan.
He suspected that the exploitation of land by HTI companies in the river upstream weakens the supporting plants to hold water. "East Kalimantan's endemic trees have turned into industrial plants," said Pradarma. "This change causes land degradation so that the water goes straight into the river."
Pradarma predicted that the IKN project will cause more frequent flooding as many trees will be cut down. He acknowledged that the government has plans to control flooding by building the Sepaku River Intake project. "Unfortunately, this project also causes flooding. It even damages the ancestral graves and ritual sites of the Balik tribe," he said.
Anggi Prayogi Putra, a researcher from Forest Watch Indonesia (FWI), said his agency had warned of a high potential for flooding in the IKN area since 2019. The study in 2021 stated that flooding in Sepaku Subdistrict is caused by high rainwater intensity, slope, and changes in forest cover.
The environmental group argued that the main factors of the flooding are extractive industry activities and the construction of the IKN project. "High rainfall is indeed among the factors, but not a trigger for flooding," said Anggi.
He explained that the area around the first ring of the IKN has been controlled by extractive industries, such as mining, HPH, HTI, and oil palm plantations. Land exploitation causes endemic trees as the main buffer for rainwater to be replaced or lost, leading to lower absorption of the River Basin Area (DAS).
"It's different if the forest cover is still maintained. Water will be stored and will not be immediately discharged into the middle or downstream," Anggi said.
The construction of the Intake Sepaku project also triggered flooding as it reduced the ability of the soil to absorb water. When high-intensity rains come, rainwater is immediately wasted on the waterways. "So, floods immediately occur," he concluded.
River and dam normalization project
Meanwhile, the IKN Authority stated that rain in the upstream area and clogged water channels led to flooding in Sepaku Village. Other factors include erosion, sedimentation, and silting of rivers.
Achmad Jaka Santos Adiwijaya, the secretary of the IKN Authority, ensured his side in tandem with several institutions, such as the North Penajam Paser Regency BPBD, Indonesian Military (TNI), Police, local governments, Ministry of Public Works and Housing (PUPR), and others have carried out flood mitigation.
"The floodwater has receded since the morning of March 18," said Jaka in a press release received by Tempo on Monday, March 20, 2023.
He explained that the IKN Authority had identified the potential for flooding in several areas in the Sepaku Village given the low zones. The IKN Authority along with other institutions is building infrastructure to deal with flooding in the area around the IKN, especially in Sepaku Village, including weirs, ponds, and retention ponds, as well as the construction of flood control in watersheds, the preparation of an integrated watershed management plan, and forest and land rehabilitation by the Mahakam Berau Watershed Management Agency.
He said the IKN Authority had coordinated meetings with several related institutions to discuss plans for handling flood prevention and control.
"The IKN Authority keeps committed to paying attention to risks and disaster management, including flooding in affected areas, including in Sepaku Village. All efforts are being practiced to minimize the impact of the disaster and maintain public safety," said Jaka.
Tempo contacted an expert staff of the PUPR Minister for Technology, Industry, and Environment, Endra S. Atmawidjaja, to gain information related to the Sepaku River Intake project. No response has been given thus far.
On a separate occasion, the Kalimantan River IV Regional Office head Harya Muldianto said the IKN area was designed to be free from flooding for the next 100 years by building many retention ponds and dams. "There is indeed no guarantee for zero flooding, but with reliable hydrology and design calculations, it can be predicted that there will be no flooding in the IKN in the next 100 years," said Harya in November 2022, as quoted from Antara.
According to him, the causes of flooding in the IKN area include heavy rainfall, sea tides, bottlenecks or narrowing culverts and provincial roads, as well as topographical conditions. He explained that until 2024, his side will take many efforts to control flooding, including a 25-kilometer river normalization project and the elimination of five narrowing culverts. "Flood control is also carried out by raising river embankments and constructing dams," said Harya.
The Sepaku River Intake project in the IKN area, he went on, has 92.23 percent completed as of March 18, 2023. It will be equipped with four pump units, each with a capacity of 600 liters per second. "Three pumps will be operated, and one pump serves as a backup," he said. The Sepaku River intake has a capacity of 3,000 liters per second and is built with the concept of an adjustable weir (Obermeyer) with a width of 117.2 meters and a height of 2.3 meters.