Estimation of Aquifer Hydraulic Parameters from Pumping Test Data Analysis: A Case Study of Baquba Shallow Unconfined Aquifer

Abstract

The groundwater resources are an important component of arid and semi-arid countries such as the Baquba area under this study. The pumping tests have conducted in the shallow unconfined aquifer (Quaternary sediments) within Baquba Local Government Area, Diyala, Iraq, for estimating of the aquifer properties as there is limited information on aquifer parameters. Drawdown and recovery data have recorded in seventeen single pumping wells and two monitoring wells locates at distances of 4 and 20 m from the pumping well in Abu-Khamis and Al-Othmania sites respectively. Type-curve matching of the drawdown and recovery data have analyzed using Cooper-Jacob's Straight-line and Thies recovery methods through computer software (Aqtesolv4.5). The ranges of the drilling borehole depth are 15m to 38.4m. The aquifer saturated thickness ranges from 8m to 26m. The outcomes of the pumping test data analysis showed that the transmissivity values ranged between 124 to 541 m²/day with an average value of 245.3m2/day. The hydraulic conductivity ranged from 7.5 to 25.6 m/day with an average value of 14.5 m/day. The specific yield ranges from 0.05 to 0.28 with an average value of 0.12. The specific capacity of the wells have ranged from 0.86 to 7.07 l/s with an average value of 2.46 l/s. The transmissivity values have analyzed according to Krasny classification system (KCS) for identifying the transmissivity variations as well as the supply potential of the groundwater within the study area. The transmissivity classification results have showed that the study area classifies as a high groundwater supply potential with slightly heterogeneous aquifer soil.