U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings
of the Technical Meeting, Colorado Springs, Colorado, September 20-24, 1993,
Water-Resources Investigations Report 94-4015
  
Field Instrumentation for Multilevel Monitoring of Hydraulic
Head in Fractured Bedrock at the Mirror Lake Site, Grafton County, New Hampshire
by
Paul A. Hsieh (U.S. Geological Survey, Menlo Park, CA), Richard
L. Perkins (U.S. Geological Survey, Bow, NH), and Donald O. Rosenberry (U.S.
Geological Survey, Lakewood, CO)
Abstract
An adjustable and removable instrument, consisting of commercially available
components, was developed for monitoring hydraulic heads at several depth
intervals in bedrock wells. The intervals are isolated from each other by
packers. Each interval is connected to an open pipe, so that the water level
in the pipe equals the hydraulic head in the interval. The water levels
are monitored by a potentiometer-float system and automatically recorded
by a datalogger. The water levels are also measured manually by a water-level
probe to check periodically the automatic measurements. The hydraulic-head
monitoring instrument can be removed from the well to accommodate activities
such as geophysical logging, water sample collection, or hydraulic testing.
This instrumentation has been installed at 12 bedrock wells at the Mirror
Lake site.
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