Rain Still Potentially Hits Semarang-Demak, Flooding Still Remains Unabated

SEMARANG, KOMPAS — Moderate rainfall is expected to continue affecting several areas in Central Java, including the city of Semarang and Demak Regency, for the next three days. This condition raises concerns about its impact on flood management efforts, which as of Friday (31/10/2025), or the tenth day, still inundate these two regions.

The weather forecaster from the Meteorology, Climatology, and Geophysics Agency (BMKG) Ahmad Yani Semarang, Winda Ratri, stated that the potential for rain in Central Java remains very high until Monday (3/11/2025). Heavy rain is expected to fall in the central mountainous regions, such as Banyumas, Purbalingga, Banjarnegara, Wonosobo, Temanggung, as well as Cilacap and its surroundings. In addition, moderate to heavy rain is also forecasted to affect Grobogan, Blora, Sragen, Karanganyar, and the surrounding areas.

The cities of Semarang and Demak have the potential for light to moderate rainfall. This situation warrants vigilance as it could hamper flood management.

"For areas that are already flooded or have experienced disasters, such as the border area of Demak in Semarang City, it is indeed necessary to pay attention and collaborate to address this flooding as soon as possible," said Winda when contacted on Friday evening.

In addition to areas currently affected by flooding, communities in flood-prone regions or around river basins are also advised by Winda to remain vigilant when heavy rain falls for an extended duration. Areas with steep topography, such as mountains, are also said by Winda to warrant caution regarding the potential for landslides.

According to Winda, rain is indeed likely to occur during the early days of the rainy season, such as in October. However, based on the weather forecast conducted by BMKG, the potential for rain currently observed is expected to be above the normal average.

"The potential for rain is indeed above the normal average or higher than the average data from the last 10 to 30 years. The average value is approximately 15 percent higher," he stated.

The ongoing rain has caused flooding in Demak Regency and Semarang City that has yet to recede, even as it enters the tenth day. On Friday, four villages scattered across Sayung District, Demak, remained inundated with floodwaters reaching heights of up to 60 centimeters (cm). A total of 16,011 individuals from 5,964 families have been affected.

Not only residential areas, but the flood also inundated the northern coastal highway in Sayung, obstructing traffic flow. The water level on the Sayung northern coastal road reached 35 cm.

In the city of Semarang, flooding continues to inundate 15 sub-districts spread across the Pedurungan, Genuk, Gayamsari, and Semarang Timur districts. The water levels vary, ranging from 10 cm to 100 cm.

A total of 40,452 individuals from 22,653 families have been affected by the flood. Of the flood victims, 299 individuals from 49 families have sought refuge in seven evacuation locations.

The flooding that occurred in Semarang has also claimed lives. As of Friday, four individuals have been reported dead after experiencing water-related accidents while engaging in activities amidst the floodwaters.

Efforts to address flooding are being undertaken by the government, one of which is through weather modification operations (OMC). This activity, which has been ongoing since Saturday (25/10/2025), is conducted to control the formation of rain clouds before they reach land.

The Deputy for Emergency Handling of the National Disaster Management Agency (BNPB), Budi Irawan, stated that the Cloud Seeding Operation (OMC) is focused on the dispersal of sodium chloride (NaCl) and calcium oxide (CaO) into potential rain clouds in the northern and southern waters of Java. In the process, BNPB, which has already deployed one aircraft, is adding another aircraft for the OMC in Central Java.

"The addition of one aircraft in the OMC operates from Adi Soemarmo Airport, Boyolali. This addition strengthens similar operations that have been ongoing from Ahmad Yani Airport, Semarang," said Budi.

In addition to conducting OMC, the government is also continuously working to reduce flooding through water suction using pumps or pumping systems. All available water pumps are said to have been deployed to drain the floodwaters. In addition to pumps owned by various agencies in Semarang and Demak, water pumps from the Regional Disaster Management Agency (BPBD) of the surrounding area have also been mobilized to enhance the efforts.

As a form of strengthening flood management through pumping, the National Disaster Management Agency (BNPB) has established a Pumping Task Force (Satgas Pompanisasi) tasked with ensuring that all pumps operate at maximum capacity for 24 hours and addressing any technical issues that arise in the field promptly.

In addition to ensuring the pumping operation, Budi also inspected the water outlets at the Terboyo retention pond, located in the Semarang-Demak Sea Wall toll road construction project area. Observations by the National Disaster Mitigation Agency (BNPB) indicated that water from the retention pond was not flowing optimally to the sea due to two closed outlets, which were being used as temporary bridges for project vehicles.

"Several immediate decisions were made, including the dismantling and construction of channels in areas that obstruct the flow of water, as well as the implementation of technical innovations to ensure that the water management system can function more effectively and sustainably. We also encourage the installation of additional pumps to expedite the drainage of water from retention ponds that have been hindered due to the construction process," said Budi.

The Central Java-DI Yogyakarta National Road Implementation Agency (BBPJN) is also involved in flood management, particularly on the national road section of Pantura Kaligawe-Sayung. The head of BBPJN Central Java-DIY, Iqbal Tamher, stated that they have begun constructing a diversion channel measuring 227 meters in length and 1.5 meters in depth from the national road at Kaligawe to a retention pond located at the back of the Sultan Agung Islamic University campus.

"Then, the water will be pumped to the Terboyo retention pond. We are targeting to complete this work by Sunday (2/11/2025), so we hope that the water level in the Kaligawe area can decrease soon," said Iqbal.

In addition, the Central Java-DIY BBPJN also installed two temporary pumps, each with a capacity of 250 liters per second, to drain the water accumulation in the Kaligawe-Sayung area. Water from that location is channeled through flexible pipes to the Dompo River in Sayung.

In the future, the Central Java-DIY BBPJN will continue the permanent handling work in the Kaligawe diversion area, as well as the construction of a pump house around the Polytron Sayung factory, which functions to channel water to the Dompo River. This work is targeted to be completed and operational by Wednesday (5/11/2025).

"We are also preparing heavy equipment to tow large vehicles trapped in the flood on the national road Kaligawe-Sayung. To access this assistance, the public can contact the PPK 3.1 Central Java Province Post Team at the number 085291957630," he said.