TECHNICAL PLANNING FOR PROGO RIVER CLIFF PROTECTION AT NGIWON SUB-VILLAGE, BANYUWANGI VILLAGE, BENDONGAN DISTRIST, MAGELANG REGENCY

• Main Author: Wati, Sella
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/69872
• Institution: Institut Teknologi Bandung

Watershed (DAS) is an ecosystem whose main elements include natural resources such as soil, water, plants, and human resources as the beneficiaries. The Progo watershed is administratively located in the districts and cities of Central Java Province and Daerah Istimewa Yogyakarta. The Progo watershed bears a heavy burden, exacerbated by the increase in population density and intensive use of natural resources, resulting in a decrease in the watershed with visible symptoms of flooding downstream of the Progo watershed and the collapse of cliffs due to abrasion and scour in the upstream of the Progo watershed. Ngiwon sub-village is one of the residential areas along the Progo river channel. Since 1995, there has been abrasion and scouring in the river channel resulting in changes in river morphology to the loss of 3,000 meters of land and ± 1.5 ha of rice fields. Moreover, from year to year, the cliff collapse that occurs is getting closer to residential areas. Therefore, technical planning was carried out as a countermeasure and protection for a 600-meter-long riverbank. Planning is conducted by determining the river's water level in Q10 and analyzing the collapse of the cliffs that occur through the HEC RAS 6.2 modeling so that an average water level of 6.36 meters and an average scour depth of 1.25 meters are obtained. Considering the modeling results, a gravity-type-revetmen (DPT) is planned as high as 9.5 meters with a budget plan of Rp. 30,832,000,000.00,- and an alternative design in the form of a 9-meter high groyne with a budget plan of Rp. 17.955,000,000.00,-.