Tidal Floods Inundate Surabaya Coastline, Disrupting Schools and Economic Activity

Tidal flooding has inundated coastal areas of Surabaya, with the Kalianak sub-district in Krembangan among the worst hit. The flooding has disrupted teaching at SD Yayasan Karya Putra, where water levels inside classrooms reached 10 to 15 centimetres, forcing students to remove their shoes. Yuli, a 44-year-old teacher, stated that while two classrooms suffered the worst flooding, lessons continued as the school was conducting a mandatory environmental orientation programme. She noted that such tidal floods have occurred two to three times a month since the school was founded in 1998, and limited funds have prevented adequate infrastructure improvements. Another teacher, Nanda, 60, observed that water levels have risen since a nearby river normalisation project on the Kalianak River was undertaken, expressing hope that authorities would address the worsening situation. Local resident Hendro confirmed that the area has experienced tidal flooding for 63 years, with water sometimes exceeding 50 centimetres. The BMKG Tanjung Perak Maritime Meteorology Station reported that coastal flooding began on 12 July and is expected to last until 17 July 2026. Sutarno, the station’s Observation and Information Coordinator, confirmed water levels of 15 to 29 centimetres on Jalan Kalimas and in Kalianak, causing traffic congestion. He attributed the extreme tidal cycle to a new moon phase, predicting peak sea levels of 120 to 160 centimetres above mean sea level between 9 a.m. and noon daily. The agency warned of significant disruptions to economic stability, port logistics, salt farming, and fisheries, as well as potential infrastructure damage from saltwater corrosion. Health risks from contaminated floodwaters, including skin diseases and diarrhoea, were also highlighted, alongside threats to freshwater sources and mangrove ecosystems. BMKG identified North Surabaya, Benowo, Kenjeran, Sukolilo, and West Surabaya buffer zones like Gresik, Lamongan, and Tuban as high-risk areas.