0 Does Jakarta Really Have a 5-Year Flood Cycle?

The claim that Jakarta’s floods follow a five-year cycle has been a persistent one, perpetuated by people ranging from occupants of high public office to bakso sellers plying their trade on the streets of the city. Major floods in 2002 and 2007 prompted fears that either last year or this one would herald particularly nasty wet seasons, but now an academic at the Netherlands’ Utrecht University has debunked the claim as a myth. “The probability of flooding occurring each year [in Jakarta] is 20 percent,” post-doctoral student Edwin Husni Sutanudjaja explained. 

He added that the so-called five-year cycle “is actually a bad interpretation ... of this statistic: flooding does not occur every five years, but every year, with a different quantity.” Edwin said the city must conduct routine dredging to reduce the sediment of rivers running through Jakarta. “Dredging needs to be done routinely each year; not just when the sediment is visible [above the water level],” he said. Jakarta Governor Joko Widodo on Saturday instructed the city’s public works office to conduct dredging along the Kali Muara River in Penjaringan, North Jakarta, to save the local fishing community, which is hit by flooding annually. 

Joko said he found many problems associated with the annual floods after visiting the area, and formulated plans to alleviate the problem. “Starting with the overflow of streets, they should be raised by another 40 centimeters,” Joko said. “The Kali Muara must also be dredged, its sediments reduced so [fishing] boats can dock [in the river].” Joko also noted problems with the area’s drainage system, which seems to not work during the flood season. “So there are many problems. 

These problems are affecting their daily lives and must be solved,” he said. “These are [temporary] solutions, but to overcome the problems [in the long term] there must be a grand design. There must be other efforts.” Jakarta has been hit with days of heavy rains sweeping across the area. The rain has caused water in some areas to overflow their drainage systems, creating crippling traffic in other parts of the capital. The Jakarta public works agency also noted that the rain and overflow have damaged roads in more than 6,400 locations covering 2.7 kilometers in length. 

The agency’s head of road and bridge maintenance, Maman Suparman, said his team has been collecting data of the severity of the damage the roads sustained including for the so-called “national roads.” National roads are major streets or highways constructed and maintained by the Ministry of Public Roads. Maman said that is would be useless to fix the roads during the rainy season. “If it’s raining the asphalt won’t dry,” he explained. “Or the roads will get holes in them again if vehicles pass over the repaired areas.” 

Among those people to previously voice the five-year claim was Coordinating Minister for People’s Welfare Agung Laksono, who in December told the Jakarta government to be vigilant of the cycle and take preventive measures. “We hope the city can act quickly,” he said. “Bad weather and high-intensity rain is part of a five-year cycle and it is predicted that January or February will be marked by continuous heavy rains.”

source : the jakarta globe