Estimating ground-water recharge from streamflow records

The purpose of this paper is to estimate ground-water recharge based on the investigation of the balance between ground-water recharge and discharge from streamflow hydrographs. Two methods of hydrograph analysis are employed in a case study of Cho-Shui River basin, Taiwan. The first is the recession-curve-displacement method, which assumes the linearity of the master recession curve while the profile of the ground-water head distribution is nearly stable. The second method is the base-flow-record estimation, which uses a relatively arbitrary procedure to estimate a continuous record of ground-water discharge (baseflow) under the streamflow hydrograph. Through implementing these two methods, the annual rates of ground-water recharge and infiltration in the area of Cho-Shui River basin are examined as our case study. Results showed that the discharge calculated by the method of base-flow-record estimation is about 16% average less than the recharge calculated by the recession-curve-displacement method in the mountain region.