Analysis of mainstay discharge in the Way Batumerah Watershed for annual water allocation plans

Abstract

This water shortage has caused drought disasters whose impact is felt both in rural areas in decreasing food production and in urban areas experiencing raw water difficulties. In the implementation of the "Water Allocation Preparation" activity, several technical approaches will be carried out including: Data Collection; Data Analysis; Prioritization of water users; Calculation of water balance; Calculation of water allocation plan; and Implementation, Monitoring and Evaluation of the Implementation of the Annual Water Allocation Plan. In the watershed of Way Batumerah, the intake area has a watershed area of 6.97 Km2 where the Batumerah Intake; Sedimentation occurs in the distribution pipe; There are two villages that are drained by intakes; There are community channels around the intake; and During the dry season, water is not enough to meet the needs of the community.The availability of water in the Batumerah River can be calculated in a period of half a month. In wet year conditions, the largest mainstay discharge (Q30%) of 1.83 m3 /s occurred in October II. In normal year conditions, the largest mainstay discharge (Q50%) was obtained at 0.89 m3/s in September II. In dry years, the largest mainstay discharge (Q80%) was obtained at 0.35 m3/s in June I. The calculation of maintenance flow needs must follow KP 02/2013 which is 5% of the existing discharge in the relevant period or Q95 according to SE Director General of Natural Resources 05/2016.The water allocation unit and allocation limit for PDAMs in the Batumerah watershed are assumed to be in accordance with the value of PDAM's water needs for the dry condition half-month, which is 0.105 m3/s. However, in certain months there is a deficit, so PDAM's water demand is the result of reducing water availability with minimum maintenance flow needs (0.001 m3/s). Water use priority is a policy that regulates the order of water allocation based on applicable laws and regulations.