LAND CONSERVATION FOR REHABILITATION OF CRITICAL WATERSHEDS: CASE IN WAY CENGKAAN, WAY BESAI SUB-WATERSHEDS, LAMPUNG, INDONESIA

Abstract

Land and water conservation are the keys to success in controlling the rate of sedimentation. The sediment runoff rate represents the catchment area that increases erosion. This study was conducted to analyze the sedimentation rate in the upstream part of the Way Cengkaan, Way Campang tributary rivers located in Pekon Karang Agung, Way Tenong District, West Lampung Regency. It was carried out from January to December 2020. The research equipment included: a current meter, a stopwatch, a rollmeter, a rainfall recorder, an automatic water level recorder (AWLR), a peiscal, sediment bottles, scales, ovens, and cups. While the materials used are sediment samples, discharge measurement results, and water level. The calculation of flow was carried out at two observation points, upstream and downstream of the Cengkaan River before entering the Way Campang River. Calculation of flow rate using the velocity-area methods using the current meter and the float method. During the observation period from January to July 2020, the sediment velocity increased in line with the trend of the sediment velocity map. The sediment velocity curve for upstream stations is steeper than for downstream stations. The sediment volume decreased relatively in December 2020, and the slope of the sediment velocity graph at the downstream observation point is larger than that at the upstream observation point. This finding reflected that in the one-year observation period from January to December 2020, the evaluation resulted from a decreasing trend of sedimentation in the Way Cengkaan River. Based on these conditions, the implementation of a land conservation program carried out in collaboration between farmer groups and beneficiary stakeholders has a positive impact and effectively contributes to improving the quality of the watershed by reducing the sedimentation rate.