KAJIAN INFRASTRUKTUR DAN SEMPADAN SUNGAI TERHADAP POTENSI DAMPAK BANJIR LAHAR DINGIN DI SUNGAI PROGO TENGAH
Abstract
Progo River becomes one of the river its upper coarse in Merapi Mountain having active status in which it is prone to materials eruption from the mountain explosion. These materials are carried away by the cold lava flood flows which can cause damages and losses influencing the condition of the infrastructure and environment of people living around the riparian areas. Riparian area functions is to maintain the protection activities, controlling activities , and the use of resources found in the river so that it can run in accordance with its goals. The research objective is to study the accordance of the condition of riparian area of Middle Progo River with the established rules. The method used was field survey assissted by the application of Survey123 for ArcGIS. The data processing used ArcGIS software. The research result shows that there are some locations are not in accordance with the established rules on riparian areas. One of the largest location having the highest settlement percentage included in riparian areas is Jatisarono Village Nanggulan Subdistrict with the areas of settlement of 0.1224 km square and 44.07% for riparian area with 50 m width and 0.1766 km square while 21.16% for riparian area with 100 m width. Jatisarono village also becomes the village with highest approximate population number within the riparian areas with 135 people in riparian area with 50 m width and 195 people riparian area with 100 m width. From the field survey result, it is found that 13 river infrastructures along the Middle Progo River consisting of 10 bridges, 2 dams, and 1 groundsill (sample) is still in fairly good condition.