Technical note: Water table mapping accounting for river–aquifer connectivity and human pressure

Abstract

A water table mapping method that accounts for surface-water–groundwater (SW-GW) connectivity and human pressure, such as pumping and underground structures occurrence, has been elaborated and tested in the heavily urbanized Parisian area. The method developed here consists of two steps. First, hard data (hydraulic head) and soft data (dry wells) are used as conditioning points for the estimation of the SW-GW connection status. A disconnection criteria of 0.75 m is adjusted on observed unsaturated zone depth (UZD). It is a default value in areas where such data are missing. The second step consists of the final mapping of the water table. Given the knowledge of the disconnection criteria, the final map is achieved with an ordinary kriging of the UZD that integrates the surface water elevation without unsaturated zone where it is relevant. The methodology is demonstrated on two datasets of UZD observations that were collected under low- and high-flow conditions.