The Impact of Land Use Change on Surface Runoff at Air Dingin Sub-watershed, Padang City Indonesia

Abstract The land load in the Air Dingin Sub-watershed is increasing due to relocation of Padang City administrative center district. Subsequently, this not only reduces catchment area but also increases surface runoff, because open green space, which originally served as a area, has been converted into settlements. A random measurement infiltration rate with double-ring infiltrometer was used method and analyzed using Kostiakov technique. capacity obtained then classified quantitatively zoning. runoff discharge Modeling System hydrology, while flow coefficient determined by analyzing topography, use, soil type data HEC-HMS modeling, HSS SCS CN Method ArcGIS 10.6. calculate value field filtration. This took account physical properties cover. performed analysis showed that 788.70 m 3 /sec, design (2010) 600.0 /sec. increased 188.70 /sec or an increase 31.45%. average 0.000002–0.5 cm/minute, there residual after percolation process 499.31 /second. caused flooding initial inundation 5.72 minutes rain. In terms zoning division based on rate, very low zone.