Yokohama drainage eyed as model for Cebu City

Storm pipes that will channel rainwater away from the streets and into rivers are being considered as one of the solutions to Cebu City’s flooding problems.

In yesterday’s Reduce Danger Zones (ReDZ) task force meeting, chairman Jose Daluz said a network of storm pipes is part of the drainage system used in Yokohama, Japan.

He said he will use Yokohama’s drainage network as a model for Cebu city.

Daluz said it starts with enforcing the three meter water easement in the Mahiga River, one of five major waterways in Cebu City.

In Yokohama, both sides of the river have a five-meter easement and a six-meter-road before any building is built, Daluz said.

The drainage system starts in Sergio Osmeña Street which serves as the boundary of the cities of Cebu and Mandaue and would stretch all the way to the city slaughterhouse at the back of a mall.

“I hope we could talk to Mandaue side also. Mandaue should do its part also because when we are going to do the riprap, it would be very long,” Daluz said.

Daluz said Yokohama uses storm pipes that are 60 meters deep.

Since the city doesn’t have tunnels like Yokohama’s, Daluz said the city can use pipes that are 30 meters deep and 100 meters long and big enough for a person to get inside.

The storm pipes in Yokohama are connected to the sewerage system that occupies 3-5 hectares and could accommodate thousands of cubic meters of rainwater.

The sewerage system will filter the rainwater and discharge it back to the river.

Daluz said the city has a Sewage Treatment Plan (STP) in the North Reclamation Area (NRA).

“This drainage system is not very difficult to implement because it doesn’t require a big amount of money. There are no informal settlers in the specified areas,” Daluz said.

Daluz also called on task force members to prepare a risk reduction plan for occupants of the Guadalupe, Bulacao, Kinalumsan, Lahug and Mahiga rivers.

At the Buhisan dam, the Cebu City government will prohibit parking along the Buhisan Road to ensure access for rescue vehicles.

Owners of illegally parked vehicles were ordered towed, Councilor Dave Tumulak said.

Tumulak is Mayor Michael Rama’s designated representative in the City Risk Reduction Management Council.

Tumulak said Metro Cebu Water District Manager Armando Paredes assured Cebu City officials of their cooperation in resolving the plight of the 2,000 families living along the Buhisan dam spillway.

Residents expressed concern on their safety after the dam overflowed twice last week.

City Administrator Jose Marie Poblete asked MCWD officials to help in the relocation of the spillway occupants as part of their corporate social responsibility.

Tumulak said MCWD officials were also asked to slowly release water from the dam into the Buhisan River without waiting for the dam to overflow.

He said MCWD officials admitted that two of the three floodgates at the dam are defective, making it difficult to release excess water into the Buhisan river.

Buhisan is one of 18 barangays identified as landslide prone in the 2008 report of the Environment Management Bureau.

Among them were barangays Lusaran, Binaliw, Guba, Budlaan, Malubog, Buot, Busay, Pamutan, Sirao, Taptap, Tagbao, Tabunan, Pung-ol Sibugay, Sudlon I and II, Sinsin, Sapangdaku and Adlawon.

Barangays Bonbon, Labangon, Kasambagan, Kinasang-an and Mabolo were also identified as the most flood prone barangays in the city.

Tumulak said he will share the EMB report with the concerned barangays so they could prepare their own disaster management plans. /Christine Emily L. Pantaleon and Doris C. Bongcac