###### Abstract  
Determination of hydrological properties of the aquifer is of fundamental importance in hydrogeological and geotechnical studies. An attempt has been made to refine the hydraulic conductivity values computed from the pumping test by utilizing the hydraulic values computed in the laboratory. This study uses hydraulic conductivity computed in the laboratory of rock samples, pumping test data in conjunction with the empirical equations, and vertical electric sounding (VES) to determine the hydraulic properties of Lower Bari Doab (LBD) in the Indus Basin of Pakistan. The utilized dataset comprises pumping test results (Kpump) from 17 water wells, hydraulic conductivity values (Klab) of different grain size subsurface lithologies, and 50 VES stations. To this end, the investigated area is divided into 17 polygons by using the Thiessen technique, and equal distribution/weight of conductivities values is assigned to 17 polygons (one polygon around each water well where pumping test is conducted). The true resistivity ranging from 20-90 Ohm-m along with an average thickness of the aquifer is computed using the VES data for each polygon. A novel approach has been developed to estimate the hydraulic conductivity of the aquifer by combining laboratory data and pumping test which is used to compute the other hydraulic properties. The calculated hydraulic conductivity, transmissivity, and tortuosity values of the aquifer range from 4.4 to 85.6 m/day, 674 to 8986 m\({}^{2}\)/day, and 13 to 20, respectively. The porosity ranges from 32 to 45% and the formation factor values fall in the range 4 to 12. Higher hydraulic conductivities were encountered in the southern portion of the area near the junction of the rivers, and it increases with an increase in porosity. The aquifer having T \(>\) 5700 m\({}^{2}\)/day and K \(>\) 40 m/day, yields a large quantity of water whereas the portion of an aquifer with T \(<\) 1100 m\({}^{2}\)/day and K \(<\) 13 m/day are combatively low yield aquifer. The results of the resistivity method show that the subsurface geological material, as depicted from true resistivity, is composed of layers of sand, clay, and silt mixed with gravel/sand. This study improves the understanding of the aquifer and will help in the development and management of groundwater resources in the area including the prediction of future behavior of the aquifer. geophysical method; hydraulic conductivity; transmissivity; porosity; formation factor +
Footnote †: journal: _Sci_  
0000-0002-4000-0002-9999-2200][PERSON]  
12305534999  
largest dams (Tarbela Dam, Mangla Dam, and Mirani Dam) but is under severe pressure due to overexploitation that continues to occur due to the rapidly increasing population that has outpaced aquifer recharge. In 2020, Pakistan faced a huge groundwater crisis due to large-scale extraction from the aquifer. About 62 billion m\({}^{3}\) of water is annually drawn from the aquifer from the Indus Basin which is about 1/3 rd of the total annual water withdrawal in Pakistan [1]. Huge pumpage has resulted in a rapid decline in water level and as a result, groundwater availability and quality have substantially deteriorated [2; 3; 4; 5]. The rapid installation of tube-wells without any geotechnical or geophysical investigation has lowered the groundwater level and has caused the salinity issue [6; 7; 8; 9; 10]. In the past, it was reported [11] a rise of more than 0.2 m per year, and in the Bahawalpur area (adjacent to Lower Bari Doab), the rate was nearly 0.4572 m per year [12]. However, in recent years, the trend has reversed [13] showed a decline of 15 m in the water table of the Upper Bari Doab since 1960. [PERSON] and [PERSON] [14] reported average change in the water table for the last several decades, the rates are shown in Table 1. It was found [15] that the yearly decline had increased to 2 to 3 m. The uncontrolled withdrawals have put the aquifer under stress by causing an imbalance between recharge and abstraction.