EVALUASI KAPASITAS SALURAN KALI BELIK YOGYAKARTA

Many urban area such as Yogyakarta has been develop rapidly in term of facilities and infrastructure. A shift function of the landuse from vacant land to built land causing problems in water resources. The occurrence of flood are really common in urban areas, due to the over capacity of the drains. One of the Yogyakarta city areas which are frequently flooded are the ones crossed by the river Belik.One of the Yogyakarta city , which are frequently flooded, is the area along Belik River. The purpose of this research are to determine the existing channel capacity, to determine the peak discharge with different rainfall intensities and to determine the maximum rainfall intensity based on the existing capacity of the drainage system. Maximum of the runoff is calculated using the rational method, while the maximum channel capacity using the method of Slope Area Manning. Landuse are dominated by land up such as buliding and settlement causing the runoff is large within a small drainage area. The channel of River Belik in Valley of UGM, Klitren and Batikan Street has the potential flooding. The result shows that the maximum capacity of the channel in Belik river the Valley of UGM can accommodate rainfall intensity of 40 mm/hour, mean while in Klitran it can accommodate rainfall intensity of 60 mm/hour, while in Batikan Street only 26 mm/hour. Research concluded that the channel of Belik River in Valley of UGM and in Batikan Street are unable to accommodate the existing runoff. The channel of Belik River in Klitren is still able to accommodate the runoff, it is because the channel is elevated