Use of seepage meters in a groundwater – lake interaction study in a fractured rock basin — a case study

López

Webb

et al. 2020

Water

The efficiency of seepage meters, long considered a fixed property associated with the meter design, is not constant in highly permeable sediments. Instead, efficiency varies substantially with seepage bag fullness, duration of bag attachment, depth of meter insertion into the sediments, and seepage velocity. Tests conducted in a seepage test tank filled with isotropic sand with a hydraulic conductivity of about 60 m/d indicate that seepage meter efficiency varies widely and decreases unpredictably when the volume of the seepage bag is greater than about 65 to 70 percent full or less than about 15 to 20 percent full. Seepage generally decreases with duration of bag attachment even when operated in the mid-range of bag fullness. Stopping flow through the seepage meter during bag attachment or removal also results in a decrease in meter efficiency. Numerical modeling indicates efficiency is inversely related to hydraulic conductivity in highly permeable sediments. An efficiency close to 1 for a meter installed in sediment with a hydraulic conductivity of 1 m/d decreases to about 60 and then 10 percent when hydraulic conductivity is increased to 10 and 100 m/d, respectively. These large efficiency reductions apply only to high-permeability settings, such as wave- or tidally washed coarse sand or gravel, or fluvial settings with an actively mobile sand or gravel bed, where low resistance to flow through the porous media allows bypass flow around the seepage cylinder to readily occur. In more typical settings, much greater resistance to bypass flow suppresses small changes in meter resistance during inflation or deflation of seepage bags.

Section: Install the Seepage Cylinder Deeper Into The Bed Sedimentmentioning

confidence: 99%

Variable Seepage Meter Efficiency in High-Permeability Settings

López

Webb

et al. 2020

Water

“…Lake-sediment temperature measurements have been used in similar studies to identify potential groundwater-inflow areas where water-quality samples could be collected and seepage rates measured to further confirm and quantify the inflow of groundwater (Jones, 2006). Lake-sediment temperatures were measured along the shorelines because groundwater inflow to lakes has been observed to decrease exponentially with distance from shore (Lee, 1977;Fellows and Brezonik, 1980;Erickson, 1981;Attanayake and Waller, 1988;Rosenberry, 1990). Other studies report the decrease in groundwater inflow with distance from a lakeshore is not exponential because of heterogeneity of the sediment (Woessner and Sullivan, 1984;Krabbenhoft and Anderson, 1986), but it was beyond the scope of this study to collect sediment temperature data for entire lakes.…”

Section: Lake-sediment Temperature Surveysmentioning

confidence: 99%

Groundwater and surface-water interactions near White Bear Lake, Minnesota, through 2011

Jones

Trost²,

Scientific Investigations Report

et al. 2013

Groundwater ‐ the disregarded component in lake water and nutrient budgets. Part 1: effects of groundwater on hydrology

Lewandowski

Meinikmann

et al. 2015

Hydrological Processes

151

Abstract:Lake eutrophication is a large and growing problem in many parts of the world, commonly due to anthropogenic sources of nutrients. Improved quantification of nutrient inputs is required to address this problem, including better determination of exchanges between groundwater and lakes. This first of a two-part review provides a brief history of the evolution of the study of groundwater exchange with lakes, followed by a listing of the most commonly used methods for quantifying this exchange. Rates of exchange between lakes and groundwater compiled from the literature are statistically summarized for both exfiltration (flow from groundwater to a lake) and infiltration (flow from a lake to groundwater), including per cent contribution of groundwater to lake-water budgets. Reported rates of exchange between groundwater and lakes span more than five orders of magnitude. Median exfiltration is 0.74 cm/day, and median infiltration is 0.60 cm/day. Exfiltration ranges from near 0% to 94% of input terms in lake-water budgets, and infiltration ranges from near 0% to 91% of loss terms. Median values for exfiltration and infiltration as percentages of input and loss terms of lake-water budgets are 25% and 35%, respectively. Quantification of the groundwater term is somewhat method dependent, indicating that calculating the groundwater component with multiple methods can provide a better understanding of the accuracy of estimates. The importance of exfiltration to a lake budget ranges widely for lakes less than about 100 ha in area but generally decreases with increasing lake area, particularly for lakes that exceed 100 ha in area. No such relation is evident for lakes where infiltration occurs, perhaps because of the smaller sample size.