Looming Disasters

KOMPAS/ISMAIL ZAKARIA

Batang Kalu Bridge in Korong Pasar Pasar, Nagari Kayu Tanam, Padang Pariaman regency, West Sumatra, is in ruins after heavy rain caused Batang Ulakan River to overflow on Monday (10/12/2018), cutting off the main connection between Padang and Bukittinggi. Traffic has been rerouted to the Padang-Sicincin-Malalak-Bukittinggi route. While waiting for the bridge to be repaired, which is expected to take six months, the Padang National Road Implementation Center III will build a temporary bridge made of a high-quality lightweight steel frame.

PADANG PARIAMAN, KOMPAS — Floods, flash floods and landslides are still an ever-present threat in a number of regions. According to a prediction by the Meteorology, Climatology and Geophysics Agency (BMKG), heavy rains have the potential cause floods in Sumatra and Java.

A number of parties have been forced to rapidly react to damages to public infrastructure due to floods, flash floods and landslides after heavy rainfall. In West Sumatra, the Padang National Road Management Agency has been building a temporary bridge after the Padang-Bukittinggi route was cut off following the collapse of the Batang Kalu Bridge in Korong Pasar Usang, Nagari Kayu Tanam, 2111 Kayu Tanam district, Padang Pariaman, at 6:30 p.m. on Monday (10/12/2018).

The bridge collapsed after the Batang Ulakan River overflowed due to heavy rains. Nearly one half of the 15-meter bridge fell into the river. The bridge was located 62 kilometers from Padang and 38 kilometers from Bukittinggi. Traffic has since been rerouted via four alternative routes.

The four routes are Padang-Pariaman-Lubuk Basung-Maninjau-Bukittinggi; Padang-Sicicin-Malalak-Bukittinggi; Padang-Solok-Batu Sangkar-Padang Panjang-Bukittinggi and another that passes through residential areas.

“We are preparing an emergency bridge. Tonight, we started building one lane to reduce the queues. Hopefully, the construction of the temporary bridge will be finished on Wednesday, but it will have a 10 ton capacity only,” chairman of the Padang National Road Management Agency, Aidil Fiqri said at the incident site on Tuesday (11/12/2018).

The collapse of Batang Kalu Bridge has not only affected transportation between Padang and Bukittinggi, but also between Padang and Pekanbaru, Riau. This is the busiest corridor for travelers and the transport of goods from cities and regencies outside Padang.

This road is also the main access route to tourism destinations for travelers headed from Padang to Pandang Panjang, Solok, Tanah Datar, Agam and Bukittinggi. The route is much quicker than the alternatives. For example, it takes 2.5 hours to travel 95 km from Padang to Bukittinggi, much faster than the 4.5 hours it takes to travel on the alternative 157 km Padang-Pariaman-Lubuk Basung-Bukittinggi route, and the 3 to 4 hours for the 126 km Padang-Solok-Padang Panjang-Bukittinggi route.

Permanent bridge

Aidil said his office was working rapidly to build a permanent bridge. "We have been making plans for two days. After the picture is finished, it will be tendered. Funds are available, contracts will soon be made and we will start the construction. The permanent bridge is expected to be completed in six months, or faster," he said.

On Tuesday, floodwaters up to 1.5 meters high inundated a number of areas in the Pekanbaru. "This is the biggest flood in the last 10 years. It used to reach only calf height at most, but today our homes are submerged to chest height," said Morizon Dahlan, chairman of the Masjid Baitul Alim at the Satitri Asri Housing Complex in Sidodadi, Tampan district, Pekanbaru.

Floods also shocked residents of Semarang, Central Java. It has been a long time since the city’s main roads have been flooded. In Malang, East Java, residents were also shocked by flash floods.

Figo, 17, a resident of Genuksari, Genuk district, Semarang, said that the intensity of the rainfall had declined in the last two days. There were traffic jams on Jl. Kaligawe Raya, which was inundated. “From the morning, trucks queued because of potholes. We fear it will be flooded again during the heavy rains,” he said.

In an anticipation of floods on the main northern coast road in Central Java, the Pemali Juana Big River Agency will operate five large-scale pumps on the Sringin River with a capacity of 2 cubic meters per second each. "Two have been installed, and the rest will be no later than tomorrow [Wednesday]," said Tesar Hidayat, head of the Water Resources Network Implementation Working Unit of the Pemali Juana Big River Agency.

In West Sumatra, the collapse of the Batang Kalu Bridge was only one of the disaster impacts in Padang Pariaman. According to the chairman of the Padang Pariaman Disaster Mitigation Agency, Budi Mulya, floodwaters reached a height of 1 to 1.5 m in 13 locations, and landslides also occurred.

No casualties have been reported, but flooding in Korong Simpang Tigo Koto Mambang, Nagari Kampung Tanjung Koto Mambang, Patamuan district, swept away one house. Meanwhile, flooding in Korong Pasa Tandikek, Nagari Tandikek, Patamuan district, severely damaged five houses, and cause slight damages to seven others.

The Batang Kalu Bridge was damaged partly because it was located not far from the river bend, so that when the Ulakan Batang overflowed, the bridge was immediately hit by water. The bridge\'s foundations were also made of stone.

Weather forecast

In Jakarta, BMKG senior officer Eko Hadi Santoso said the Madden-Julian Oscillation (MJO) factor was predicted to be active in the western part of Indonesia, next week. The flow of a wet air mass from the western Indian Ocean toward the western part of Indonesia has triggered a high volume of rainfall in a number of regions.

"The active MJO will raise the volume of rainwater and trigger hydrometeorological disasters, including floods, tornadoes and landslides. The threat of disasters will continue to lurk for the next few days in Sumatra and Java," said Eko.

A few days ago there was also a cold air mass flow from Asia, known as the Asian cold monsoon. This increased rainfall in Indonesia. The weather conditions often include strong winds, tornadoes and heavy rain within a short time. Temperature increases of more than 5 degrees will also occur between 7:00 a.m. and 10:00 a.m., triggering the growth of cumulonimbus clouds.

During heavy rains, according to Eko, people should avoid sheltering under trees so as not to be struck by lightning, and if there were strong winds, stay safe from falling trees.

Based on data from the National Disaster Mitigation Agency, throughout 2018 there have been 727 windstorms, 609 floods and 429 landslides. (ZAK/ SAH/ DIT/ E01)