Analisis Pengaruh Perubahan Tata Guna Lahan Terhadap Debit Banjir Kota Magelang Wilayah Timur Saluran Irigasi Progo Manggis

Abstract

Land cover change in Kota Magelang occurs every year. The conversion is caused by population and economic growth, hence size area of permeable area plummets. Land cover change influences land infiltration rate. This research was performed to investigate drainage discharge changes in 2013, 2015, and 2017 caused by land cover change. Moreover, flood discharge of 2017 was compared to flood discharge caused by RTRW Kota Magelang. Design rainfall was analyzed by using Thiessen polygon method and frequency analysis. Then, analysis was continued by catchment area delineation and land cover analysis to acquire surface run off coefficient. After that, calculation of flood discharge was carried out by utilizing rational equation. Findings showed that drainage discharge grew as result of built up area rose. Comparison of drainage discharge in year of 2013, 2015 and 2017 showed drainage debit surge. Several catchment area drainage discharges in year of 2017 were almost similar with drainage discharge generated by RTRW plan.