Groundwater

The most productive aquifers in the Parker River basin are in the western third of the basin and consist of ice-contact deposits composed of sand and gravel, which were deposited in stream channels and temporary lakes in contact with glacial ice. Most of the aquifers in the eastern two-thirds of the basin consist of sandy glacial-outwash deposits, which are generally thin and less permeable than the ice-contact deposits. These outwash deposits, however, may be productive where buried beneath younger marine or swamp deposits in the central part of the basin.

The largest yields are likely where the coarser ice-contact deposits underlie or interfinger with outwash. Most aquifers in the basins, both ice-contact and outwash, are extensively overlain by organic swamp deposits, which may result in excessive iron concentrations in groundwater. Yields of large-diameter, gravel-packed wells in glacial deposits are as much as 500 gal/min, and the average yields of small-diameter, driven wells are about 10 to 22 gal/min. In addition, bedrock supplies small amounts of groundwater almost anywhere.