o - Waste Isolation Pilot Plant

3.6 Dewey Lake, Rustler, and Salado Formation Behavior In the
Exhaust Shaft
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The Exhaust Shaft was drilled and lined between 1983 and 1985. During that
time, site investigations did not report the presence of groundwater within 195
feet of the surface. During sinking and mapping of the Exhaust Shaft the
shallowest fluid production noted was from the Magenta and the Culebra
dolomites. Both aquifers were instrumented with piezometers to monitor
hydraulic heads. In addition, the Dewey Lake, the Forty-niner, the Tamarisk and
the unnamed member of the Rustler Formation were also instrumented with
piezometers as well as the contact between the Rustler/Salado Formations to
monitor the hydraulic heads in those stratigraphic units. Figure 3.26 provides the
location and depth of the gauges located in the Exhaust Shaft in feet and meters
below the top of the collar.
Figures 3.27 - 3.33 are linear plots of the fluid pressure expressed in poundsper-square
inch (psi) versus time in calendar years (years) for the gauges
monitoring the Dewey Lake Formation, the Forty-niner member, the Magenta
member, the Tamarisk member, the Culebra member, and the unnamed
member of the Rustler Formation and the contact between the Rustler/Salado
Formations.
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Figure 3.34 is a plot of precipitation versus time from a climatological monitoring
station located at the WIPP Site for the period extending from August 1 1996 ­
August 31, 1997. Long-term precipitation data may be useful in evaluatin"
infiltration. Figure 3.34 shows that there was significant rainfall between June­
July 1996 and June-August 1997.
3.7 W1PP Site Precipitation
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