Web Enabled “Conjunctive Use Model for Management of Surface and Ground Water using concept of MAR and ASR”

Abstract

A comprehensive user friendly web-enabled “Conjunctive Use Model for Management of Surface and Ground Water using concept of MAR and ASR” has been developed using semi- analytical approaches for management of surface and ground water in a recharge basin, based on the concept of managed aquifer recharge (MAR) and aquifer storage treatment and recovery (ASTR). The model for simulation of aquifer responses due to recharge and extraction of recharged water has been developed by integrating the hydrologic components into the basic water balance equation; and the models for simulation of contaminants’ fate in the recharge basin and through the soil column underneath have been developed by considering: (i) in-basin mass balance with decay of contaminant and, (ii) 1-dimensional advection-dispersion-decay equation coupled with linearized sorption isotherm kinetics, respectively. The estimate of hydrologic components included; inflow to the recharge basin from its catchment by SCS-CN model, water surface evaporation by combination of Priestley-Taylor and Penman method, recharge by Hantush’s basic equation for water table rise due to recharge from a rectangular spreading basin in absence of pumping well, and drawdown due to pumping by Theis’s well function equation. The contaminant’s fate estimate included; time varying changes in concentration due to assimilation and detention of contaminant in the recharge basin and transport of assimilated materials through saturated soil column until they reached the groundwater table. Duhamel’s convolution equation and method of superposition have been used to obtain the resulting water table position due to pumping and recharge, and also for computation of contaminants’ fate. The performances of recharge-pumping and contaminants’ transport models have been illustrated by examples. These models can successfully be used and upscale as potential tools for MAR and ASTR. The web-enabled GUI interface is an efficient tool to provide a platform to users and professionals for calculating time-varying depth of water in, and groundwater recharge from, a recharge basin consequent to the pumping in the vicinity of the basin for recovery of recharged water. This could also allow users to simulate the contaminant transport process in the basin and through the saturated soil column before mixing with the groundwater. Therefore, a web-enabled GUI interface has been developed for general access of the models. Using the web-enabled interface, users can use the models for computation and to visualize the outputs in graphical as well as tabular format.