Integrated modelling of potential recharge in small recharge ponds

Abstract

Integrated models that simultaneously simulate potential recharge and time delay for wetting front to reach water table are necessary for comprehensive and coordinated planning of managed aquifer recharge. Most of the existing models do not simultaneously simulate the potential recharge, length of advancement of wetting front, and time delay for wetting front to reach water table except the few numerical models, which are data intensive, high initial software and data setup cost, spatial and temporal discretisation depended accuracy, and time-consuming. This paper presents an integrated potential recharge simulation (IPRS) and time delay for wetting front to reach water table (TDWF) models for simultaneously simulating the potential recharge and time delay for wetting front to reach water table under time-variant inflows and outflows, respectively. The models have been derived by integrating the modified Green-Ampt model for variable water depth into the water balance equation of recharge pond. The numerical calculations of the IPRS and TDWF models are performed by the computer program written in Fortran-95. The performance comparison of the IPRS and TDWF models with HYDRUS-1D model for a hypothetical recharge pond over variety of soils showed its ability and comparability with the HYDRUS model. The models have also been successfully demonstrated for a recharge pond in a watershed in a semi-arid region of India. The IPRS model was found to be sensitive to the changes in inflow and saturated hydraulic conductivity of the bed soil of the recharge pond. The derived models will be helpful in simultaneous simulating the potential groundwater recharge and time delay to reach water table and optimum design and evaluating the effectiveness of recharge ponds and/or other surface artificial groundwater recharging facilities of any shape and size in the field.