Anthropogenic influences on morphological changes in the Progo River, Daerah Istimewa Yogyakarta Province, Indonesia

Abstract

Changes in the river morphology require knowledge of the suite of drivers that control it, whether natural or human. The study aims to analyze the anthropogenic influences on morphological changes in the Progo River using Google Earth Images. It is essential to know the recent changes in the morphology of the Progo River so that stakeholders can make policies to control human activities that influence the morphology changes of the Progo River. The study area is located in Bantul Regency, Daerah Istimewa Yogyakarta Province, Java Island, Indonesia. The size of ​​the Progo River watershed is around 17,432 square kilometers. Google Earth Images analysis is carried out to analyze the morphological changes of the Progo River from 2012 to 2019. The result shows that land-use changes due to dam construction affected the sediment supply downstream of the dam. In addition, land-use changes around the Progo River due to the opening of agricultural land and settlement areas had an effect on decreasing the infiltration area, so that the number of trees holding the soil from erosion was reduced, producing more eroded sediment that flowed to the river. Sand mining in the river could cause the deepening of water depths and a decrease in the average height of the riverbed.

Quality of surface water due to sand mining activity: a case study from the Progo River, Daerah Istimewa Yogyakarta Province, Indonesia

“…Several construction structures are found along the Progo River, such as revetment, bridge, intake of irrigation, weir, and groundsill. In addition, human activities such as sand mining and opening up agricultural land were also reported along the Progo River [22]. The Progo River is one of the rivers with a volcanic and non-volcanic source of sediment [21].…”

Correlation of lithofacies and depositional environment using Markov chain analysis in Sambipitu formation at Ngalang river, Gunungkidul, Yogyakarta, Indonesia

“…The zone of Blow (1969) was used to determine the age and the depositional environment according to Phleger (1951) and Tipsword et al (1966). Current morphological and rock conditions around a river can describe the past condition of the river, such as rocks formed or lithology, geological structure, current erosion and sedimentation process (Zamroni et al, 2020). Sedimentation process requires some flow current, such as turbidity current in a basin as transportation media (Selley, 1985).…”