| Abstract: | The U.S. Geological Survey ‘s National Center is on a 105-acre tract straddling rocks of two distinct types. These are pelitic schists of late Precambrian or early Paleozoic age; and sandstone, shale, siltstone, conglomerate, and diabase of Triassic age. Two observation wells and two core holes were drilled on the part of the property underlain by Triassic sedimentary rocks. The wells were drilled to monitor water levels, for equipment testing and to determine the hydraulic properties of the Triassic rocks. Geophysical logs were run and lithologic logs prepared from drill cuttings and cores. An aquifer test was conducted and indicated that the transmissivity is about 40 sq ft/day. Flowmeter surveys showed that the water comes from two thin zones, presumably bedding plane partings. The flowmeter surveys, core samples, and geophysical logs suggest that the Triassic sandstone is a fractured-rock aquifer. A water sample taken at the close of the aquifer test was low in dissolved solids, soft, and of excellent quality. (Woodard-USGS) |
| Genre: | USGS Numbered Series |
| ProdID: | 9964 |
| Citation Author: | Larson, J. D. |
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| Citation Language: | ENGLISH |
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| Citation Phsyical Description: | 36 p., :ill., map ;27 cm. |
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| Citation Publisher: | U.S. Geological Survey, |
| Citation Series: | Open-File Report |
| Citation Series Code: | OFR |
| Citation Series Number: | 78-144 |
| Citation Search Results Text: | Hydrogeology of the observation well site at the United States Geological Survey National Center, Reston, Virginia; 1978; OFR; 78-144; Larson, J. D. |
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| Citation Year: | 1978 |
| Type: | citation/reference |
| Text: | Hydrogeology of the observation well site at the United States Geological Survey National Center, Reston, Virginia; 1978; OFR; 78-144; Larson, J. D. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/usgs_thumb.jpg |
| Date Other: | Sat, 1 Jan 1994 00:00 -0600 |
| Publisher: | U.S. Geological Survey, |
