Quantifying groundwater-surface water exchange: Development and testing of Shelby tubes and seepage blankets as discharge measurement and sample collection devices.

摘要

Quantification of groundwater-surface water exchange and the role of hyporheic flow in this exchange is increasingly of interest to a wide range of disciplines (e.g., hydrogeology, geochemistry, biology, ecology). The most direct method to quantify groundwater-surface water exchange is a seepage meter, first developed in the 1940s. Widespread use of the traditional 1970s-era 55-gallon half-barrel seepage meter has shown that the method is subject to potential errors, particularly in flowing waters (e.g., streams, rivers, tidal zones). This study presents two new direct seepage measurement devices, the Shelby tube and the seepage blanket, designed to minimize potential measurement errors associated with flowing surface waters. The objective of the study is to develop and test the new methods by comparing results (specific discharge, hydraulic conductivity, and dissolved constituent concentration) to established methods. Results from both laboratory and field testing suggest that the new devices have utility in quantifying the water and dissolved constituent exchange between surface water and groundwater.