Comparison of Selected Methods for Estimating Groundwater Recharge In Humid Regions

Method:	Category:	Spatial Scale:	Temporal Scale:	Quantity Estimated:	Ease of Use:	Data Needs:	Cost:
Seepage Meters	Streamflow	Point	Event to Months	Potential Recharge	Moderate	Low	Low
Seepage meters directly measure stream infiltration at a point beneath the streambed, providing an estimate of potential recharge that could reach the water table from that point on the stream. A seepage meter is a cylinder (such as half of a 55-gal drum) that is driven into the bed of a surface-water body. The top of the cylinder is attached to an expandable bag, partially filled with water. Changes in the volume of water in the bag indicate the infiltration rate through the streambed. Seepage meters are not difficult to construct and install in sediments and data are simple to evaluate. Installation is not possible in bedrock. Recharge estimates can be derived for individual events or days. Recording flowmeters can be used to obtain longer-term estimates.