DISTRIBUTION OF THE SAN ANDRES LIMESTONE, ARTESIAN AQUIFER
IN THE ROSWELL BASIN OF SOUTHEASTERN NEW MEXICO, U.S.A
Dr. William M. Turner
As part of the effort to develop computer models of the Roswell Artesian Basin for the
purpose of managing water rights transfers, the Technical Section of the Office of the
State Engineer for the State of New Mexico in the United States evaluated the
transmissivity distribution within the San Andres limestone aquifer. The discussion
that follows is adapted from Rao (1991) and supplemented.
The Roswell Ground-Water Basin covers a large area in the Pecos River valley in
southeastern New Mexico (Figure 1). The basin is bounded
on the west by the Sacramento Mountains, about 80 miles (129 km) distant from the Pecos
River; on the east by the foot of the High Plains of Texas, about 25 miles (40 km) from
the Pecos River; on the south by the Seven Rivers Hills. The northern boundary of
the Roswell Basin is near Vaughn, New Mexico about 90 miles (145 km) north of Roswell, New
The surface elevation within the Roswell Basin declines from about 10,000 feet (3,048
m) at the crest of the Sacramento Mountains on the west to about 3,500 feet (1,067 m) at
the Pecos river east of Roswell, New Mexico. From the Pecos River, the surface rises
eastward to 4,000 feet (1,219 m) at the foot of the High Plains of Texas (Hantush,
The geologic formations involved in the transmission, storage and confinement of ground
water in the Roswell Basin are the shallow alluvium deposits, the Chalk Bluff Formation,
the San Andres Formation and the Yeso Formation (Hantush, 1957).
Alluvium deposits form the Shallow Alluvial aquifer. The Chalk Bluff Formation
forms the upper semi-confining aquitard overlying the San Andres Limestone artesian
aquifer. The Yeso Formation forms the semi-confining aquitard below the San Andres
Fiedler and Nye (1933, p.249) discuss the general nature of the distribution of
transmissivity of the artesian aquifer. According to Fiedler and Nye, the Roswell
basin artesian aquifer can be divided into five high permeability and four low
permeability zones as shown in their Plate 41. These alternate and approximately
parallel high and low permeability zones appear to extend from west to east. Fiedler
and Nye provide some hydrogeological explanation for the pattern of transmissivity
distribution (p. 183)
Hantush (1957) reported transmissivity values ranging from 56,000 to 1,465,000 gpd/ft
(694 to 18,166 m2/) based on four aquifer-performance tests (APTs) in the San
Andres Limestone artesian aquifer. The APTs were made in areas where the aquifer is
well developed and apparently is more permeable than in undeveloped areas of the
basin. All of Hantush's APTs were performed in the high permeability zones defined
by Fiedler and Nye (1933, Plate 41). Hantush (1957) noted that it is probable that
the portions of the aquifers separating the developed areas are less permeable. He
also presented a set of representative transmissivities for different parts of the Roswell
Artesian Basin (Hantush, 1957, Table 5)
Hantush (1961) reported one more transmissivity value of 1,890,000 gpd/ft (23,460 m2/d)
for the San Andres Limestone in the Northwest One-Quarter of the Southeast One-Quarter of
the Southeast One-Quarter of Section 33, Township 10 South, Range 25 East, New Mexico
Principal Meridian, Central Zone.
Havenor (1968, p.13) reported a transmissivity of 1,500,000 gpd/ft (18,600 m2/d)
in Township 12 South, Range 24 East based on personal communication with Mervin L. Klug.
Information regarding the specific location of the well or the nature of the pumping test
is not given. This data is not used in the analysis of transmissivity
Kinney et al. (1968, Figure 11) presented a map of transmissivity distribution of
the San Andres Limestone based on data from Hantush (1957, 1961), an APT apparently
made by the United States Geological Survey for which no reference is given, and
transmissivity values calculated from the specific capacity of wells. Transmissivity
values calculated from specific capacities are not provided.
Saleem and Jacob (1971) analyzed a number of step-drawdown tests from data in the files
of Smith Machinery Company of Roswell, New Mexico. The company routinely ran
step-drawdown tests to determine the optimum pump size for wells. These tests are of
short duration. They lasted up to about two hours. Saleem and Jacob (1971)
present 82 transmissivity values for the San Andres Limestone artesian aquifer.
Summers (1972) presented some additional transmissivity data obtained by application of
Harrill's equation (Harrill, 1971) to eight step-drawdown tests run on seven wells in
Rabinowitz et al. (1977) presented a map of transmissivity distribution of the Roswell
artesian basin. The information on APT transmissivities used in the preparation of
the map apparently were provided by W. K. Summers through personal communication. At
the time of writing this report, these data could not be confirmed. These data
points are not used in the analysis of transmissivity distribution.
Appendix A is a listing of available transmissivity data for the San Andres Limestone
artesian aquifer. The data were analyzed to study the statistical pattern of their
Rao (1991) plotted the transmissivity data on normal-probability paper. The data
significantly deviated from the theoretical, normal-distribution line. He concluded
that the transmissivities distribution does not follow a normal statistical probability
The natural-logarithms of the transmissivity values are plotted in Figure 2. The data points closely follow the theoretical
lognormal-distribution curve. This means the statistical distribution of aquifer
transmissivities in the San Andres Limestone aquifer is satisfactorily explained by a
lognormal probability density function. The chi-square goodness of fit test in the Table 1 supports this finding.
We conclude from the work of previous workers as analyzed by Rao (1991) and the present
author that the transmissivity within the San Andres Limestone aquifer is lognormally
Fiedler, A.G. and Nye, S.S., 1933. Geology and Ground-Water Resources of the
Roswell Artesian Basin, New Mexico. U.S. Geological Survey
Hantush, M.S., 1957. Preliminary Quantitative Study of the Roswell Ground-Water
Reservoir, New Mexico. New Mexico Institute of Mining and
Bureau of Mines and Mineral Resources Division.
Hantush, M.S., 1961, Aquifer Tests on Saline Water Wells near Roswell, New
Mexico. New Mexico Institute of Mining and Technology,
Harrill, J.R., 1971. Determining Transmissivity From Water-Level Recovery of a
Step-Drawdown Test (in Geological Survey Research 1970).
Survey Professional Paper 700-C, C212-C213.
Havenor, K.C., 1968. Structure, Stratigraphy, and Hydrogeology of the Northern
Roswell Artesian Basin, Chaves County, New Mexico. New Mexico
of Mines and Mineral Resources Circular 93.
Kinney, E.E., J.D. Nations, B.J. Oliver, P.C. Wagner, T.A. Siwula, and R.E.
1968. The Roswell Artesian Basin. Roswell Geological
Rabinowitz, D.D., G.W. Gross, and C.R. Holmes, 1977. Environmental tritium as
hydrometeorologic tool in the Roswell Basin, New Mexico,
parameters. Journal of Hydrology, 32:35-46.
Rao, B., 1991, Roswell Basin Analytical Groundwater Flow Model - Users Manual,
Report TDH-91-2, New Mexico State Engineer Office, March,
Saleem, Z.A. and C.E. Jacob, 1971. Dynamic Programming Model and
Analysis, Roswell basin, New Mexico. New Mexico Water Resources
Institute, WRRI Report 10.
Summers, W.K., 1972. Application of Harrill's Equation to a Limestone
Ground Water, 10(4), p.21-23.