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Determination of bench-mark elevations at Bethel Island and vicinity, Contra Costa and San Joaquin counties, California, 1987

Open-File Report 88-498

By:
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Abstract

Elevations of 49 bench marks in the southwestern part of the Sacramento-San Joaquin River Delta were determined during October and November 1987. A total of 58 miles of level lines were run in the vicinity of Bethel Island and the community of Discovery Bay. The datum of these surveys is based on a National Geodetic Survey bench mark T934 situated on bedrock 10.5 mi east of Mount Diablo and near Marsh Creek Reservoir. The accuracy of these levels, based on National Geodetic Survey standards, was of first, second, and third order, depending on the various segments surveyed. Several bench marks were noted as possibly being stable, but most show evidence of instability. (USGS)

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Determination of bench-mark elevations at Bethel Island and vicinity, Contra Costa and San Joaquin counties, California, 1987
Series title:
Open-File Report
Series number:
88-498
Edition:
-
Year Published:
1988
Language:
ENGLISH
Publisher:
U.S. Geological Survey,
Description:
iv, 11 p. :maps ;28 cm.