| Abstract: | Two glaciodeltaic outwash terraces in southern
Rensselaer and northern Columbia Counties, known
locally as the Schodack and Kinderhook terraces,
consist of ice-contact and outwash sand and gravel and
together form a regional, unconfined, stratified-drift
aquifer with a combined area of 18.75 square miles.
The hydrogeology of these aquifers is summarized on
four maps at 1:24,000 scale, that depict (1) locations of
wells and test holes, (2) surficial geology, (3) altitude
of the water table, and (4) altitude of the bedrock
surface.
Both terraces are associated with a thin and
probably discontinuous confined aquifer consisting of
beds of glaciofluvial sand and gravel derived from the
outwash deltas that form the two terraces. The confined
aquifer is overlain by thick deposits of lacustrine silt
and clay. Consultants? estimates of average hydraulic
conductivity, based on aquifer tests conducted at four
test wells screened in thicker sections of the confined
aquifer, range from 430 to 2,360 ft/d (feet per day),
with a mean of 1,150 ft/d. The mean estimate of
hydraulic conductivity derived from specific-capacity
data from 16 test wells screened in confined and
unconfined sections of the aquifer is 640 ft/d.
Reported yields for domestic wells completed in
unconfined sections of the Schodack and Kinderhook
terrace aquifers average 16.1 and 18.3 gal/min (gallons
per minute), respectively, and reported yields of
domestic wells completed in hydraulically confined
sections of these terraces average 15.3 and 12.8 gal/
min, respectively. Yields from public-supply wells
screened in the confined sections of the Schodack
Terrace aquifer range from 50 to 1,050 gal/min and
average 305 gal/min. Average annual recharge to the
Schodack Terrace aquifer and adjacent upland till
deposits, as estimated in a 1960 U.S. Geological
Survey study, were 16.3 and 7.1 inches per square
mile, respectively. Bedrock that underlies the study
area has been highly modified by tectonic activity,
differential weathering, and preglacial erosion which
produced about 900 ft of relief on the bedrock surface.
A major thrust fault that runs north-south through the
area separates autocthonous Ordovician rock units to
the west from allocthonous Cambrian (Taconic) rocks
to the east. |
| Genre: | USGS Numbered Series |
| ProdID: | 31109 |
| Citation Author: | Reynolds, Richard J. |
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| Citation Language: | ENGLISH |
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| Citation Phsyical Description: | 4 maps ;117 x 61 cm., on sheets 133 x 82 cm., folded to 20 x 18 cm. +1 pamphlet (73 p. : ill., map ; 28 cm.) |
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| Citation Series: | Open-File Report |
| Citation Series Code: | OFR |
| Citation Series Number: | 97-639 |
| Citation Search Results Text: | Hydrogeology of the Schodack-Kinderhook area, Renssealaer and Columbia counties, New York; 1999; OFR; 97-639; Reynolds, Richard J. |
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| Citation Year: | 1999 |
| Type: | citation/reference |
| Text: | Hydrogeology of the Schodack-Kinderhook area, Renssealaer and Columbia counties, New York; 1999; OFR; 97-639; Reynolds, Richard J. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/usgs_thumb.jpg |
| URL (DOCUMENT): | http://ny.usgs.gov/pubs/of/of97639/OF97-639.pdf |
| URL (PLATE): | http://pubs.usgs.gov/of/1997/0639/plate-1.pdf |
| URL (PLATE): | http://pubs.usgs.gov/of/1997/0639/plate-2.pdf |
| URL (PLATE): | http://pubs.usgs.gov/of/1997/0639/plate-3.pdf |
| URL (PLATE): | http://pubs.usgs.gov/of/1997/0639/plate-4.pdf |
| Date Other: | Sat, 1 Dec 2001 00:00 -0600 |
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