Brantas Upstream Region Causes Flooding in Batu City

KOMPAS/DEFRI WERDIONO

Officers clean up the remnants of mud and materials on Jalan Raya Dieng, Sidomulyo Village, Bumiaji District, Batu City, East Java, Thursday (4/11/2021) night, after being hit by flash floods in the afternoon that hit the area.

BATU, KOMPAS—Nearly two hours of heavy rainfall on Thursday (4/11/2021) afternoon triggered a flash flood in the city of Batu, East Java. Watery mud from the upstream region of the Brantas River carried garbage and fallen trees to devastate several villages and swept away at least 10 people. The impact of the flood was also felt by the residents of Malang who live along the Brantas River.

As of 8:45 p.m., the Batu Regional Disaster Management Agency (BPBD) reported that seven of the 10 missing people had been found, while the search was continuing for the remaining three.

"There were reports of 20 missing people, but some had only been separated [from their families]," Batu BPBD preparedness and logistics head Achmad Choirur Rochim said in Batu on Wednesday.

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The areas most affected by the flash flood were located in Bumiaji district, namely the villages of Sumberbrantas, Bulukerto, Sidomulyo, Tulungrejo, and Padang Rejo, all of which are located along the Brantas River.

Bulukerto village was badly affected, its roads covered in mud. It also experienced a power outage. In Sidomulyo, the flood swept a fallen tree into a resident's house.

In Jurangsusuh, a fallen banyan tree had cut off the access road connecting Batu with Karangploso in Malang regency, while a car was swept away by a mudslide on Jl. Dieng.

Kompas

Map of Batu City and Malang City

Extreme rain

Batu saw heavy rainfall from 2:30 p.m. to 4:00 p.m. Climatology station head Anung Suprayitno, from the Malang office of the Meteorology, Climatology and Geophysics Agency (BMKG), said that Batu recorded 72 millimeters of rain fell in 1.5 hours, within the “very heavy-extreme” category. Rainfall of this volume over 24 hours belonged to the “very heavy” intensity level.

Floodwaters from the partly converted hills located in the upstream region of the Brantas River destroyed a number of structures, including bridges. As of Thursday evening, it was still drizzling in Batu amid the ongoing efforts to clean up the debris on roads using heavy equipment.

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Teams from the Batu BPBD, the TNI (Indonesian Military), the National Police (Polri), and the local community were trying to clean up thick mud and fallen trees blocking the road to Batu. A number of residents closed access to their villages as a security precaution.

Preliminary data on material losses recorded by the Batu BPBD includes four vehicles that were swept away in the flash flood and one submerged house. Other losses are being inventoried.

Warning

Batu Mayor Dewanti Rumpoko said the city was still focused on cleaning up mud and fallen trees, as well as providing supplies for affected residents.

Dewanti acknowledged that the BMKG’s Malang office had warned of extreme weather from November 2021 to February 2022. The warning had been disseminated to a number of parties to be on the alert and take anticipatory measures.

“Before the rainy season, we were already working to clean up the environment, but that was [all] we could do. What was visible, what was affordable. Well, then there were big trees from within the forest that came from [underground]. We weren’t able to see those [so] couldn’t get rid of them," said the mayor.

KOMPAS/DAHLIA IRAWATI

Dozens of residents of RT 1 RW 9 Jatimulyo Village, Lowokwaru District, Malang City, Thursday (11/04/2021), evacuated to safe places after the flash flood in Batu City. More than 60 houses in the area were inundated by mud up to 1 meter high.

Dewanti added that the presence of mud indicated a decline in land cover. Several years ago, she added, the Batu administration had launched a “one name, one tree” reforestation program for the local hills.

BPBD Malang head Alie Mulyanto said that the flash flood in Batu had also affected Malang. Preliminary data showed that dozens of houses were flooded for up to an hour with up to 0.5 meter of water. "Those [areas] affected by the floods were settlements on the banks of the Brantas River," said Alie.

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The residents of at least 69 houses on Jl. Bougenvil RT (neighborhood unit) 001/RW (community unit) 009 in Lowokwaru, Malang, were trying to clean up the mud that had entered their homes.

"There were no early [warning] signs. It was not raining, either. Towards sunset, there was a sudden roar and immediately, a flood of mud came. Soon, the water flowed into the houses, breaking through kitchen walls and doors," said Lasmini, 67, a resident of RT 011/RW 002 in Samaan village, Klojen, Malang.

Arief, 38, also a resident of Samaan, said that the mud that had entered his house reached as high as an adult's calves. In fact, his house was on an elevated foundation and was located 10-15 meters from the riverbank.

This article was translated by Hyginus Hardoyo.