Estimation of natural groundwater recharge in the Aguascalientes semiarid valley, Mexico
Groundwater recharge (GWR) is analyzed and evaluated within the Aguascalientes Valley by means of a modified linearized Boussinesq equation and the Water Table Fluctuations (WTF) technique. These techniques use the specific yield, water table variations and the subsurface drainage of groundwater. The methodology is applied to the semiarid Aguascalientes valley, which contains a thick vadose zone. The combination of the analytical solution based on the Boussinesq equation and the WTF technique, allows the method to be applied in areas with deep groundwater levels, such as the Aguascalientes valley, without the need for high temporal resolution data. The data for the application of the method were provided by various government agencies and includes information on 145 wells positioned within the valley during the period 1985-2015. The specific yield and the transmissivity were integrated from the results of two previous investigations. Results indicate that the variation of recharge ranges from 0.86 to 525.69 mm/year in the analyzed period, with the highest recharge rates occurring in the north and center parts of the valley and is likely attributed to high specific yield and vertical hydraulic conductivity due to the presence of coarse permeable soils present in the area. Conversely, the lowest recharge rates were found to occur near the north and south borders of the valley.