Quantification of temporal distribution of recharge in karst systems from spring hydrographs

"The estimation of the temporal distribution of recharge in karst aquifers is a challenge due to large heterogeneities in geometric and hydraulic parameters of the vadose and phreatic zone. This article provides a time-continuous approach for the estimation of inflow into the conduit system of a karst aquifer which consists of the sum of direct recharge and flow from the fissured matrix blocks into the conduit system.

Abstract
Summary: The estimation of the temporal distribution of recharge in karst aquifers is a challenge due to large heterogeneities in geometric and hydraulic parameters of the vadose and phreatic zone. This article provides a time-continuous approach for the estimation of inflow into the conduit system of a karst aquifer which consists of the sum of direct recharge and flow from the fissured matrix blocks into the conduit system. The approach employs the first time derivative of the spring hydrograph and the recession coefficient of the conduit system for the determination of this function. The first time derivative of the hydrograph describes the rate of change in spring discharge. It reflects the ratio of inflow to and outflow from the conduit system. The recession coefficient depends on the hydraulic diffusivity, which controls the velocity of the signal transmission through the system. "

Geyer, Birk, Steffen, Liedl, Rudolf, Sauter, Martin

Journal of Hydrology Volume 348 Pages 452-463 Issue 3/4