Characteristics of Unconfined Aquifer Based on Pumping Test on Wells Made by residents in the Biromaru Area Sigi Regency

Abstract

The Biromaru area, located in Sigi Regency, is an agricultural area that was once relies heavily on Gumbasa irrigation in the management of rice fields and farming businesses plant another. Aftermath of the earthquake on September 28, 2018 Gumbasa irrigation canal suffered such severe damage that it could no longer drain the rice fields in the Biromaru area. As a result, most of the people have a livelihood in farming in the fields seeks to carry out independent exploration and exploitation of groundwater. The purpose of this study is to determine the characteristics of unconfined aquifer which includes Transmissivity (T), Storativity (S) and Specific yield (Sy) in the research area. The data collection method used is the pumping test method, long term test and step drawdown test and the analytical method used is the curve-fitting method Neuman, Theis recovery and Hantush Bierschenk for well efficiency performance analysis. Based on the well test and aquifer test as well as lithological correlation results, the Transmissivity value is 315-600 m2/day, Storativity 2.15X10-2 - 6.17X10-3, Specific Yield 1.34X10-1-2.86X10-1, Hydraulic Conductivity 1.19X102-36.4 m/day. and permeability 16,488 m/day. The potential for groundwater discharge in the study area is 226.067 cm3/day. The maximum available discharge is 2.01 X 10-2 m3/s, the value of B = 4.76 X 10-3 and the value of C = 1.8 X 10-5. Aquifer Loss 90.1%, Well Loss 9.9% and Well Efficiency (Ew) 88.3%.