Flooding on Java’s northern coastline causes havoc

High tide and three-metre waves from the Java Sea inundate roads linking Semarang to other cities. Various areas are under water, impacting local shrimp hatcheries. Rainfall is not the cause. Climate change is bound to aggravate the problem.

Jakarta (AsiaNews) – Unprecedented tides have hit the northern coastline of the island of Java[*], flooding local towns and cities. High water levels and three-metre waves were triggered by the perigee[†], the Meteorological Office in Semarang (Central Java) reported.

As in the past, tidal waters from the Java Sea breached protective seawalls, pouring onto the coastline, especially the city of Semarang, despite the absence of rain.

For years, local authorities and the central government have tried to solve the problem of tidal floods, aggravated in recent years by climate change.

Seawalls were built on the Banger River to control water levels and stem flooding with a system of dikes and polders[‡] designed to limit the impact of tidal waters.

When tides rose, they caused havoc in the city, inundating several residential areas with hundreds of homes submerged by seawater.

The main roads between Semarang and other cities in East Java were also affected, with vehicular traffic backed up with five-kilometre queues.

The Tanjung Mas seaport was also severely impacted, whilst other coastal towns reported major damages, including to shrimp hatcheries, a major local economic activity, with serious financial losses to local producers. Luckily, no one has been killed or injured so far.

Meteorologists and other experts note that the tidal surge occurred without heavy rainfall, suggesting that it is linked to broader climate anomalies.

More sudden floods could come in the next few days along the entire northern coast, said Eko Prasetyo, weather forecaster at Indonesia’s Meteorology, Climatology and Geophysics Council (BMKG[§]). “Local residents have been informed of the potential and imminent danger,” he explained.

The latest episode began on 14 May repeating itself every other day, with waves varying in height depending on the shape of the coastline.

[*] Known in Indonesian as Pantura (North Coast) or Pantai Utara Jawa (North Jawa Beach).

[†] The perigee of the moon is the point when the moon is closest to the Earth, which causes the Perigean spring tide.

[‡] Artificially created coastal flood plains.

[§] Badan Meteorologi, Klimatologi, dan Geofisika.