STUDY OF FLOOD CONTROL AND MORPHOLOGY OF THE JEROAN RIVER IN MADIUN REGENCY

• Main Author: Ummah, Rif'atul
• Format: Theses
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/71279
• Institution: Institut Teknologi Bandung

Jeroan River is a tributary of the Madiun River located in the Madiun District. The problem that occurred in Jeroan River is flood happen several times . Floods are caused by high rainfall, the influence of bankfull capacity, changes in land use and the presence of backwater from Madiun River. This research was conducted to analyze the causes of flooding, flood control and river morphology in order to evaluate and complement the flood control study conducted in 2018. Hydrological and hydraulic analysis was carried out using the HEC-HMS 4.10 and HEC-RAS 6.1 programs. The area of the Jeroan Basin is ± 620 km2 with the length of the main river of ± 36 km. The Jeroan watershed modeling is divided into 5 subbasin, namely Upper Jeroan Subbasin, Mejayan Subbasin, Klitik Subbasin, Piring-Sono Subbasin and Muneng Subbasin. In this study, calibration was carried out 4 times including hydrological calibration, manning calibration, model results calibration and canal bottom change calibration. Based on the results of the study, flooding was caused by an increase in R25 of 17% at the Gemarang station, 13% at the Saradan station and 12% at the Muneng station. Backwater only occurs when Madiun River on the highest water level elevation and does not occur when the water level elevation in on average daily The effect of the backwater of the Madiun River increases the water level of the Jeroan River by 0.85-1.65 meters (at the most critical cross) with a length of influence of up to ±15 km from downstream. Changes in land use increase the planned flood discharge by 4%. Q25 was obtained for each subbasin of 322.2 m3/s in Upstream Jeroan Subbasin, 344.9 m3/s in the Mejayan Subbasin, 96.1 m3/s in the Klitik Subbasin, 223.8 m3/s in the Piring-Sono Subbasin, and 149.4 m3/s in the Muneng Subbasin. In this study, an evaluation was carried out on planning the results of the 2018 study using the planned flood discharge from the 2022 calculation results, it was found that the results of the 2018 planning could handle 49% of flood from initially being able to handle 100%. Jeroan River tends to experience bed degradation with a degradation of 149,646 tonnes/year and an aggradation of 121,145 tonnes/year. The biggest degradation occurred at sta J- 610 of 1.2 m/year. The addition of 2 groundsills upstream and downstream of the bridge on J-177 can overcome the degradation of Jeroan River.