RESEARCH· ·1970·

GEOLOGICAL SURVEY RESEA~RCH 1970
TRANSMISSIVITY AND STORAGE COEFFICIENT OF AQUIFE:Rs IN
THE FOX HILLS SANDSTONE AND THE HELL CREEK FORMATION,
MERCER AND OLIVE'R COUNTIES, NORTH DAKOTA
By MACK G. CROFT and E. A. WESOLOWSKI, Bismarck, N. Oak.
Work done in 0001Jeration with the North Dakota State Water
Commission and the Nwth Dakota Geological Survey
Abstract.-Since 1963, about 100 flowing stock and domestic
wells have been drilled into the Fox Hills Sandstone and the
Hell Creek Formation in Mercer and Oliver Counties, N. Dak.
Aquifer tests were made on about half of the wells. The values
obtained for transmissivity range from 13 to 3,100 gallons per
day per foot, and average 510 gallons per day per foot. An
analysis of the potentiometric surface in the southwestern part
of Mercer County indicates a transmissivity of about 1,400
gallons per day per foot. The values for permeability average
16 gallons per day per square foot. Data indicate storage coefficient
values are between 1o-' and 1QJ. The aquifer tests indicate
that the wells have specific capacities that range from less
than 0.1 to 0.6 gallon per minute per foot.
The purpose of this investigation is to determine the
transmissivity, storage coefficient, and permeability of
aquifers in ·the Fox Hills Sandstone and Hell Creek
Forn1ation by use of df;tta from flowing stock and
domestic wells in l\1ercer ~nd Oliver Counties, N. Dak.
About 100 flowing wells have .been drilled in this area
since 1963. The investigation is part of the general cooperative
water-resources study of the area which began
in 1966.
Mercer and Oliver Counties, in west-central North
Dakota, ino1ude approximately 1,840 square miles and
are bordered on the . north and east by the Missouri
River. -
The well-numbering system used in this report is
based on the location of the well in the Federal system
of rectangular surveys of public lands. The first numeral
denotes the township north of a base line, the
second denotes the range west of the fifth principal .
meridian, and the third denotes the section in which
the well is located. The lowercase letters "a," "b," "c,"
and "d" designate, respectively, the northeast, northwest,
southwest, and southeast quarter sections as well
as the quarter-quarter sections. For example, well 141-
81-13db is in the NWl/i SEll! sec. 13, T. 141 N., R.
81 w.
Numerous geologic and hydrologic investigations of
artesian aquifers have been made in North Dakota and
adjoining areas. The earliest geologic investigations
pertinent to this report were made by Lloyd and Hares
( 1915) and Stanton ( 1920). Recent geologic investigations
have been made by Johnson and Kunkel (1959),
Denson and Gill ( 1965), and Pipiringos, Chisholm,
and Kepferle (1965). The flow-test method used to
determine the transmissivity and storage coefficient
was devised by Jacob and Lohman ( 1952). Hydrologic
studies similar to this investigation were made of the
Fox Hills Sandstone and the lower part of the Hell
Creek Formation in Montana by Taylor (1965, 1968).
G'EOLOGY
Geographically the area is part of the glaciated Missouri
Plateau. l\1ost of the flowing wells are in the
stream valleys, which are incised 400 to 600 feet below
the plateau surface.
Geologic formations exposed in the region range
from Cretaceous to Quaternary in age. The bedrock
formations, partly capped by a veneer of glacial drift,
dip gently to the northwest at rubout 10 feet per mile
into the Williston basin (Denson and Gill, 1965, pl.
5; Johnson and Kunkel, 1959, p. 1). Test drilling and
core analyses in Mercer and Oliver Counties indicate
that the Fox Hills Sandstone and the Hell Creek For-
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U.S. GEOL •. SURVEY PROF. PAPER 70o-B, PAGES Bl9D-B195