Application of Subsurface Soil Temperature as a Tracer to Estimate Recharge from Managed Aquifer Recharge Structures

Temperature can be used as a tracer to characterize vertical recharge rates of fluids through soil. The objective of the present study is to estimate the groundwater recharge from a percolation pond using temperature as a tracer and to assess the temporal and spatial variation on the effect of clogging. Temperature data from different depths at the pond bottom were collected for four different time periods using temperature sensors. These temperature measurements were modelled using the 1DTempPro software. Input parameters required for this model are depth to the temperature sensor from the pond bottom, time series temperature data and sediment properties such as porosity, thermal conductivity, dispersivity and heat capacity. The rate of recharge during the early periods of rainfall is more which gradually decreases afterwards. These results were also compared with the recharge rates calculated by conventional water balance method. The decrease in recharge rate at the pond bottom is attributed to the clogging of suspended particles present in the water. The groundwater temperature data and associated analytical tools are formal solutions for groundwater flow rates and are still underused and not yet utilized to its full potential.