EVALUASI TIMBULNYA GENANGAN PADA CATCHMENT AREA SISTEM PEMATUSAN GREGES YANG DILAYANI RUMAH POMPA GREGES DI RAYON GENTENG SURABAYA

Abstract

Drainage systems in Surabaya at Genteng is Greges drainage system with a area of 1520 ha served by Greges Pumping Station has one primary channel is Greges channel. One of the primary channel at Genteng, Greges channel which is increase of the 17 secondary channel. Pumping station at Genteng, especially Greges drainage system in addition of Greges pumping station server the Greges primary channel there are 4 pumping station is Gadukan, Morokrembangan, Dupak Bandarejo, and Asem Jaya. The research variables in the Greges drainage system are pumping capacity at Greges, Gadukan, Morokrembangan, Dupak Bandarejo, and Asem Jaya, the flow discharge to the primary channel of Greges channel, and the flow discharge to the secondary channel. The methods used are hydrology and hydraulics calculations, comparison of current and initial pump capacity, analysis of Standard Operating Procedure (SOP) of pump house operation of Greges, Gadukan, Morokrembangan, Dupak Bandarejo, Asem Jaya, and cost calculation of the plan. The results showed at Genteng especially Greges drainage system Greges channel which is increase that the condition of the existing 5 secondary channel is Tembok Gede, Semarang, Margo Rukun, Demak Timur, and Dipak are not able to serve discharge which cause sediment. Other factor, the cause of more inundation the absence of a Standard Operating Procedure (SOP) operating pump in Greges, Gadukan, Morokrembangan, Dupak Bandarejo, and Asem Jaya in regulation occurred of inundation area of flood 5.71 ha time of flood 240 minutes and water level of flood 40 cm at 16 April 2016 is one of the largest of flood at Genteng that takes place in Greges drainage system. Sediment dredging was selected as the plan, obtained dredging cost with 10,697 m3 sediment volume of Rp. 148.076.680,00.