Analysis of Sand Mining Impacts on Riverbed in the Downstream of the Progo River, Indonesia

The Progo River is a river that flows in the Province of Central Java and Yogyakarta Province in Indonesia. This river originates at Mount Sindoro with the main river length of about 138 km and has a watershed area of approximately 243,833,086 hectares. The Progo River is a natural river which has one of its upper reaches, which is sourced from Mount Merapi. This condition resulted in the Progo River being affected by the material carried by cold lava. The research method is carried out by analysing the amount of sand mining, social and economic impacts, sediment transport, degradation or aggradation at the point of review based on primary and secondary data from the results of laboratory measurements and tests. The location of the research was carried out at the point of the Srandakan Bridge to the Progo River Estuary. The results showed that at the Srandakan Bridge point to the Progo River Estuary the volume of sand mining was 459,576 m³/year, one of the social and economic impacts of sand mining was the opening of job opportunities for the community around the mining location, and degradation of the river bed, with a degradation value of 0.43 m/year. (paper)