Series of Floods on Java Island due to Embankment Breaks

The widespread impact of flooding due to breached embankments is a sign that regular maintenance of embankments must be carried out frequently.

The following article was translated using both Microsoft Azure Open AI and Google Translation AI. The original article can be found in Rentetan Banjir di Pulau Jawa akibat Tanggul Jebol

A series of embankments that broke, causing floods, and even flash floods in a number of areas, especially in Central Java, need to be watched out for. Moreover, in the next few days, the Meteorology, Climatology and Geophysics Agency warned that extreme weather could potentially still occur.

In the last two months, high amounts of rain resulted in rivers overflowing in several areas, causing embankments to break and flooding residential areas, causing damage and even loss of life.

In Grobogan Regency, Central Java, heavy rain for several days resulted in water in the Lusi River exceeding capacity and overflowing, flooding residential areas and the main roads in the city center of Purwodadi District, Grobogan Regency on Thursday (13/3/2024). Floods were also caused by water coming from upstream areas.

The flood, which initially inundated 40 villages in 12 districts, on Saturday (16/3/2024) expanded to a total of 113 villages in 13 districts affected. In other words, 68 percent of Grobogan Regency has been affected by floods, rendering the city center in Purwodadi paralyzed.

KOMPAS/P RADITYA MAHENDRA YASA

Vehicles belonging to residents can be seen driving through floodwaters on Semarang-Grobogan Road in Gubug District, Grobogan Regency, Central Java, on Tuesday (6/2/2024).

The Grobogan Regency Regional Disaster Management Agency (BPBD) reported that 13,341 houses were flooded, one house was heavily damaged, and eight others were slightly damaged.

In addition, as many as 80 educational facilities were affected, 7 river embankments were breached, and 4,352 hectares of agricultural land were inundated and facing crop failure. The floods have also forced 692 people to evacuate to safer locations after their homes were submerged with flood levels ranging from 15 cm to 100 cm.

At the beginning of this year, the Grobogan Regency area experienced flood disasters twice. Previously, in early February, namely Tuesday (6/2/2024), heavy rain throughout the day flooded 2,662 residents' houses in 34 villages from 12 sub-districts.

Several train journeys were also hindered due to flooding which submerged railway tracks. The floods that occurred for three days were triggered by heavy rain in the area, causing water to overflow in three river basins, namely Lusi River, Serang River, and Tuntang River.

Also read: Thousands of Houses in Grobogan Submerged in Floods

Beware of broken embankments

Flood disasters resulting from the breach of levees have also occurred in the Demak Regency, Central Java. The neighboring district of Grobogan also experienced flood disasters in mid-March.

The high intensity of rainfall and the breakage of the levee at the Dombo River in Menur Village, Mranggen Sub-district, has exacerbated the second flood to hit this year. As of March 13-16, the floodwaters have not receded yet.

Reportedly, 65,109 people have been affected and 2,163 individuals displaced. The affected infrastructure includes 73 places of worship, 10 healthcare facilities, 30 educational institutions, and 10 office facilities.

Floods also occurred in the Demak area in early February. In fact, the strong current of water caused 10 points of embankments in several rivers to break, including the Tuntang River, Cabean River, Jratun River and Wulan River.

The influx of water from several breached embankments caused floods that inundated residential areas up to a height of 2 meters. It is reported that 35 villages in 7 districts, with a total population of 72,123 people, were affected, resulting in 15,645 refugees.

Repairs to several breached embankments have caused floods in several villages in the districts of Karanganyar and Gajah, which have not receded for a week. Especially the embankment of the Wulan River, which has a considerable breach of almost 30 meters in width. The floods also resulted in the closure of the Demak-Kudus coastal road.

The breach of a levee that resulted in flash floods in Pekalongan, Central Java, on Wednesday (3/13/2024) claimed the lives of two individuals. The flash floods occurred in the village of Wangandowo, Bojong district, Pekalongan regency, after the levee of a dam in the village collapsed due to the inability to contain the heavy rainfall runoff.

In a short amount of time, water with a height of around 1 meter mixed with mud swept through a residential area. According to the temporary records of BPBD Pekalongan, one bridge was damaged, one kindergarten building was damaged, two prayer rooms were damaged, two houses were washed away, 20 houses were heavily damaged, and 50 houses were lightly damaged (Kompas.id, 14/3/2024).

Another pantura region that was hit by floods twice this year is Brebes Regency, Central Java. Floods with heights up to 1 meter submerged 23 villages in 7 sub-districts due to high intensity rainfall on Sunday (25/2/2024).

Continuous heavy rain has caused an increase in the water levels of the Cigunung and Pemali Rivers. At the same time, three river embankments have collapsed, causing the water to overflow into residential areas and farmland. As many as 30,556 residents from 8,358 households have been affected, and 934 individuals have had to evacuate.

Another flood disaster occurred on Wednesday (6/3/2024) in several villages in Losari District, Brebes. Hundreds of houses were reported to be submerged in flood waters, as a result of the breaching of the embankment of the Cisanggarung River.

The breach of the embankment was reported at three points in Babakan Village, Bojongsari Village, and Karangsambung Village. As a result, a total of 525 houses in the area were flooded. A total of 775 households were affected by the flood.

Also read: Flooding in Indonesia is not just a result of extreme weather

Embankment maintenance

Based on the results of mapping carried out by the Cimanuk-Cisanggarung River Basin Center (BBWS), there are 93 river embankments that are vulnerable to breaking in Brebes Regency. Of this number, 25 embankments have been handled, while the other 68 embankments have not been handled (Kompas, 16/11/2021).

The information has signaled that the repair of the levee must be immediately addressed in order to prevent wider impacts and trigger floods if it breaks. The breaching of the river dam that caused floods in several areas in Central Java recently serves as a reminder to regularly check vulnerable levees as a precautionary measure.

Regular checks and maintenance are needed to prevent embankment landslides at various points that can cause river siltation and reduce embankment capacity. Considering the occurrence of embankment breaches due to weather conditions, an evaluation of embankment capacity that is adjusted in the event of potential extreme floods should also be carried out.

Especially with the weather forecast from BMKG mentioning Central Java as one of the areas under the alert category predicted to be overshadowed by extreme weather such as heavy rain accompanied by strong winds that could cause hydro-meteorological disasters.

BMKG has detected the emergence of three tropical cyclone seeds in the vicinity of Indonesia. This condition has the potential to cause extreme weather in several regions of Indonesia until early next week (14-18 March 2024).

KOMPAS/P RADITYA MAHENDRA YASA

Residential areas located below the embankment were affected when the Tuntang River overflowed in Gubug District, Grobogan Regency, Central Java on Wednesday (29/3/2023). Heavy rain with high intensity in the upstream area caused flooding in several areas. Some river levees are also vulnerable to collapsing, which could potentially cause flooding in residential areas.

Three sikon seeds are the tropical cyclone seeds 91S, 94S, and 93P that are monitored around the southern Indian Ocean of Java, Timor Sea, and Australia Sea. All of them have shown the impact on the southern region of Indonesia.

Apart from the resulting cyclone seeds, the Madden Julian Oscillation (MJO) activity in quadrant 4 contributes to the growth of strong convective clouds in the Central Java region. This also affects the increase in potential for extreme weather.

Based on the record of the Central Java BPBD, extreme weather is the biggest contributor to disasters in the region throughout 2024. From January 1 to March 8, 2024, out of 104 disasters that occurred, 47 were caused by extreme weather, 37 were floods, and 18 were landslides.

The disaster claimed 12 lives. In order not to cause a wider disaster and more victims, prevention efforts by maintaining embankments are a good anticipatory step. (R&D COMPAS)

Also read: Beware of the Impact of Even Rain in Jakarta