Report Title: Freshwater resources and saline water near the Sac
and Fox Nation tribal lands, eastern Lincoln County, Oklahoma
Report Number: WRIR 96-4173
Author: Marvin M. Abbott
Abstract
The purpose of this project was to evaluate the freshwater resources
and possible sources of high-chloride and high-sulfate concentrations
in parts of the aquifer near the Sac and Fox Nation tribal land in
eastern Lincoln County, Oklahoma. Water-quality sampling and borehole
geophysical data indicate the potential for fresh ground water on
tribal land generally is greatest in the Vanoss Formation, in the
SE1/4 sec. 21, T. 14 N., R. 06 E. and in the NE1/4 sec. 22, T. 14 N.,
R. 06 E. These locations avoid the flood-prone areas and borehole
geophysical resistivity logs indicate the altitude of the base of
fresh ground water is below 650 ft. The altitude of the base of fresh
ground water is indicated to be generally near the surface under the
W1/2 sec. 22, T. 14 N., R. 06 E., the SE1/4 sec. 22, SE1/4 SE1/4 NE1/4
sec. 21, and NE1/4 NW1/4 NW1/4 sec. 27.
Conditions are more favorable for placement of fresh ground-water
wells in sec. 34, T. 14 N., R. 06 E., where the tribe has leased
water rights, than on tribal land in secs. 15, 16, 21, and 22, T. 14
N., R. 06 E. Sandstones overlain by or enclosed in thick clay and
shale sequences are likely to be somewhat isolated from the flow
system and retain some of the residual brine. Borehole geophysical
logs suggest that sandstones near CH1, CM1, and WT1 have more clay and
shale content than the sandstones near L2. Greater amounts of clay in
the sandstones will retard the flushing of residual brines from the
sandstones and could result in a shallow base of fresh water near CH1,
CM1, and WT1. For these reasons and because circulation of fresh
ground water is limited by discharge to the Deep Fork, general water
quality under tribal land would probably be poorer than in the area
where the tribe has leased water rights.
Samples have chloride or sulfate concentrations greater than 250
milligrams per liter in the W1/2 sec. 22, T. 14 N., R. 06 E. Six
cluster well samples from tribal land have chloride or sulfate
concentrations above the suggested maximum contaminant levels set by
U.S. Environmental Protection Agency.
Water-quality data indicate there may be more than one source for the
salinity in the very saline and briny samples near the tribal
land. Two possible sources for chloride and sulfate in water-quality
samples are shallow brines and deep oil brines. Probable sources of
shallow brines in the study area are: 1) solution of minerals by fresh
water moving through the aquifer and 2) residual brines deposited with
the sediment. There are no salt or gypsum beds in the Vanoss, Ada, or
Vamoosa Formations, but there may be nodules and finely disseminated
minerals present in the formations. Residual brines could remain in
sand stones and shales that have low hydraulic conductivity and have
not been diluted by freshwater recharge. Data suggest both sources
have mixed with the fresh ground water from the Vanoss Formation. This
is indicated by the relations of the bromide/chloride concentration
ratio to chloride concentration, delta deuterium to delta
18oxygen, and by delta 18oxygen to chloride molality
relation.
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Last modified: Mon May 24 08:34:45 1999