Beauheim 1987 - Waste Isolation Pilot Plant - U.S. Department of ...
Beauheim 1987 - Waste Isolation Pilot Plant - U.S. Department of ...
Beauheim 1987 - Waste Isolation Pilot Plant - U.S. Department of ...
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Thus, at three <strong>of</strong> the four locations where data have<br />
been collected on both Magenta and Forty-niner<br />
hydraulic heads, vertical hydraulic gradients are<br />
upward from the Magenta to the Forty-niner. Data<br />
from the fourth location, DOE-2, are too ambiguous<br />
to allow definition <strong>of</strong> the gradient. These<br />
observations imply that, at least at H-3, H-14, and H-<br />
16, precipitation cannot be infiltrating through the<br />
Dewey Lake Red Beds and other formations<br />
overlying the Rustler and recharging the Rustler<br />
below the Forty-niner. Furthermore, unless and until<br />
a water table is detected in the lower Dewey Lake<br />
and its hydraulic head is measured, the possibility <strong>of</strong><br />
recharge from the surface reaching even the Fortyniner<br />
cannot be evaluated. Efforts are currently<br />
undeway to determine whether or not a water table<br />
exists in the Dewey Lake at H-3 and H-16, but<br />
resolution <strong>of</strong> the question may take several years.<br />
In summary, a more complete understanding <strong>of</strong><br />
vertical hydraulic-head relations among the Rustler<br />
members is available today than existed in 1983.<br />
Data from the WlPP underground facility (Peterson et<br />
al., <strong>1987</strong>) and H-16 indicate a potential for an upward<br />
gradient from the Salado to the lower Rustler. Data<br />
from Mercer (1983) and from H-16 indicate that<br />
upward hydraulic gradients exist between the<br />
unnamed lower member <strong>of</strong> the Rustler and the<br />
Culebra over much <strong>of</strong> the WlPP site. Attempts to<br />
collect representative data on the formation pressure<br />
<strong>of</strong> the Tamarisk have failed to date, but recent data<br />
from DOE-2, H-14, and H-16 support Mercer’s<br />
observation <strong>of</strong> downward hydraulic gradients from<br />
the Magenta to the Culebra at the WlPP site.<br />
Together these observations imply that the Culebra,<br />
the most transmissive member <strong>of</strong> the Rustler, acts as<br />
a drain on the overlying and underlying Rustler. The<br />
data from H-3, H-14, and probably H-16 indicate that<br />
the present hydraulic gradient between the Fortyniner<br />
and the Magenta is upward at those locations,<br />
effectively preventing modern precipitation at the<br />
surface from recharging the Magenta or deeper<br />
Rustler members. Figure 6-3 illustrates these<br />
relationships.<br />
E<br />
G E W<br />
cwm<br />
DEWEY LAKE RED BEDS<br />
ANHYDRITWGYPSUM ?<br />
CLAYSTONE<br />
ANHYDRITE/GYPSUM<br />
MAGENTA DOLOMITE MEMBER<br />
2 I I<br />
.?<br />
I<br />
A<br />
CLAYSTONE<br />
ANHYDRITEIGYPSUM ?I I<br />
0<br />
U<br />
a CULEBRA DOLOMITE MEMBER I J.<br />
CLAYSTONE. HALITE, GYPSUM<br />
LEGEND:<br />
DIRECTION OF HYDRAULIC GRADIENT<br />
BETWEEN TWO WATER-BEARING UNITS<br />
SILTSTONE<br />
SALAD0 FORMATION<br />
+<br />
?<br />
UNKNOWN DIRECTION OF HYDRAULIC GRADIENT<br />
BECAUSE OF UNKNOWN HEAD IN UNIT<br />
Figure 6-3. Vertical Hydraulic-Head Relations Among the Rustler Members at the WlPP Site<br />
137