Link to USGS home page

Water Resources of North Dakota

STREAMFLOW CHARACTERISTICS OF
STREAMS IN THE UPPER RED RIVER OF
THE NORTH BASIN, NORTH DAKOTA,
MINNESOTA, AND SOUTH DAKOTA

By Gregg J. Wiche and Tara Williams-Sether

U.S. GEOLOGICAL SURVEY Open-File Report 97-416


Prepared in cooperation with the
SOUTHEAST CASS WATER RESOURCE DISTRICT and the
CASS COUNTY JOINT WATER RESOURCE DISTRICT

Table of Contents

Definition of Terms

Abstract

Introduction

History of the stream-gaging program in North Dakota

Explanation of station summaries

Data considerations

References

List of streamflow gaging stations (Table 1)

Streamflow statistics

05030000 Otter Tail River near Detroit Lakes, MN
05030500 Otter Tail River near Elizabeth, MN
05040000 Pelican River near Detroit Lakes, MN
05040500 Pelican River near Fergus Falls, MN
05046000 Otter Tail River below Orwell Dam near Fergus Falls, MN
05047500 Mustinka Ditch above West Branch Mustinka River near Charlesville, MN
05048000 Mustinka Ditch below West Branch Mustinka River near Charlesville, MN
05048500 West Branch Mustinka River below Mustinka Ditch near Charlesville, MN
05049000 Mustinka River above Wheaton, MN
05050000 Bois de Sioux River near White Rock, SD
05050500 Bois de Sioux River near Fairmount, ND
05051000 Rabbit Creek at Campbell, MN
05051500 Red River of the North at Wahpeton, ND
05051522 Red River of the North at Hickson, ND
05051600 Wild Rice River near Rutland, ND
05051700 Wild Rice River near Cayuga, ND
05053000 Wild Rice River near Abercrombie, ND
05054000 Red River of the North at Fargo, ND
05054500 Sheyenne River above Harvey, ND
05055000 Sheyenne River near Harvey, ND
05055100 North Fork Sheyenne River near Wellsburg, ND
05055200 Big Coulee near Maddock, ND
05055500 Sheyenne River at Sheyenne, ND
05056000 Sheyenne River near Warwick, ND
05057000 Sheyenne River near Cooperstown, ND
05057200 Baldhill Creek near Dazey, ND
05058000 Sheyenne River below Baldhill Dam, ND
05058500 Sheyenne River at Valley City, ND
05058700 Sheyenne River at Lisbon, ND
05059000 Sheyenne River near Kindred, ND
05059500 Sheyenne River at West Fargo, ND
05059600 Maple River near Hope, ND
05059700 Maple River near Enderlin, ND
05060000 Maple River near Mapleton, ND
05060500 Rush River at Amenia, ND
05061000 Buffalo River near Hawley, MN
05061500 South Branch Buffalo River at Sabin, MN
05062000 Buffalo River near Dilworth, MN
05062200 Elm River near Kelso, ND
05062500 Wild Rice River at Twin Valley, MN
05064000 Wild Rice River at Hendrum, MN
05064500 Red River of the North at Halstad, MN


DEFINITION OF TERMS

Climatic year is the 12-month period April 1 through March 31. The climatic year is designated by the calendar year in which it begins.

Cubic foot per second (ft3/s) is the rate of discharge representing a volume of 1 cubic foot passing a given point during 1 second and is equivalent to 7.48 gallons per second or 448.8 gallons per minute or 0.02832 cubic meters per second.

Discharge is the volume of water in the "natural" channel of a stream that passes a given point within a given period of time. Discharge often is used interchangeably with the term "streamflow".

Drainage area (of a stream at a streamflow-gaging station) is the area, measured in a horizontal plane, enclosed by a topographic divide from which direct surface runoff from precipitation normally drains by gravity into the stream upstream from the station.

Drainage basin is a part of the surface of the Earth that is occupied by a drainage system, which consists of a surface stream or a body of impounded surface water together with all tributary surface streams and bodies of impounded surface water.

Gage height is the water-surface elevation referred to some arbitrary gage datum. Gage height often is used interchangeably with the more general term "stage", although gage height is more appropriate when used with a reading on a gage.

Gaging station is a particular site on a stream, canal, lake, or reservoir where systematic observations of hydrologic data are obtained.

Ground water is the water in the ground that is in the zone of saturation, from which wells, springs, and ground-water runoff are supplied.

Hydrologic unit is a geographic area representing part or all of a surface drainage basin or distinct hydrologic feature as delineated by the Office of Water Data Coordination on the State Hydrologic Unit Maps; each hydrologic unit is identified by an eight-digit number.

Instantaneous discharge is the discharge at a particular instant of time.

Mean is the arithmetic average of a list of values.

Mean discharge is the arithmetic mean of individual discharges during a specific period.

Partial-record station is a particular site where limited streamflow data are collected systematically over a period of years.

Period of record is the time during which a stream-gaging station is in operation and for which the records are published.

Probability of occurrence is the likelihood that an event will occur. Probabilities are generally expressed as a decimal number between 0 and 1. If the probability is 0, the event will not occur; if the probability is 1, the event will occur absolutely. Probability also can be expressed as a percent, where 0 percent corresponds to 0 probability and 100 percent corresponds to a probability of 1.

Recurrence interval is the average time interval between occurrences of a hydrologic event of a given or greater magnitude, usually expressed in years.

Regulation is the artificial manipulation of the flow of a stream.

Stage see "gage height"

Standard deviation is a measure of the variability of the values in a list of values.

Stream-gaging station is a gaging station where a record of discharge of a stream is obtained.

Streamflow see "discharge"

Surface water is the water on the surface of the earth.

Water year is the 12-month period October 1 through September 30. The water year is designated by the calendar year in which it ends and which includes 9 of the 12 months.


ABSTRACT

Statistical summaries of streamflow data for all active and inactive gaging stations for the Red River Basin upstream of and including Halstad, Minnesota, are presented in this report. The summaries for each streamflow-gaging station include (1) manuscript (station description), (2) graph of the annual mean discharge for the period of record, (3) statistics of monthly and annual mean discharges, (4) graph of the annual flow duration, (5) monthly and annual flow duration, (6) probability of annual high discharges, (7) probability of annual low discharges, (8) probability of seasonal low discharges, (9) annual peak discharge and corresponding gage height for the period of record, and (10) monthly and annual mean discharges for the period of record.

INTRODUCTION

A part of the mission of the United States Geological Survey is the collection of systematic data to determine the quantity as well as the quality and use of surface and ground water. A total of 7,292 streamflow-gaging stations (as of 1994) were operated by the U. S. Geological Survey in the United States, Puerto Rico, and the Trust Territories of the Pacific Islands (Wahl and others, 1995). Of the 7,292 streamflow-gaging stations, 60 were operated in the Red River Basin upstream of Emerson, Manitoba, excluding the Devils Lake Basin.

At streamflow-gaging stations, the water level in the river is monitored continually. A relation between water level and discharge is developed by making periodic discharge measurements throughout the range in water level. This relation is referred to as a station rating. A continuous record of streamflow is computed for each gaging station by using the water level record and the station rating.

Knowledge of the magnitude and time distribution of streamflow is essential for all aspects of water management and environmental planning. Federal, State, and local agencies responsible for the development and management of North Dakota's surface-water resources use this knowledge for making safe, economical, and environmentally sound water-resource planning decisions.

Streamflow statistics published in annual state water reports by the U. S. Geological Survey include records of daily mean discharge, annual high and low discharge, and annual mean discharge. Other statistics can be retrieved from U.S. Geological Survey computer files. Water resource managers must go to various sources to obtain the necessary statistics. These sources may only include active gaging stations listed in the most recent annual report and, thus, overlook information available for many inactive gaging stations.

The purpose of this report is to provide a comprehensive publication summarizing streamflow characteristics for all active and inactive gaging stations for the Red River Basin upstream of and including Halstad, Minnesota, excluding the Devils Lake Basin. Active and discontinued gaging stations that have a least 10 years of record are listed in table 1

Table 1. List of streamflow-gaging stations for which streamflow statistics
                are published in this report Continued
_______________________________________________________________________________

Station
                Station name
number
_______________________________________________________________________________

05030000  Otter Tail River near Detroit Lakes, MN
05030500  Otter Tail River near Elizabeth, MN
05040000  Pelican River near Detroit Lakes, MN
05040500  Pelican River near Fergus Falls, MN
05046000  Otter Tail River below Orwell Dam near Fergus Falls, MN

05047500  Mustinka ditch above West Branch Mustinka River near Charlesville, MN
05048000  Mustinka ditch below West Branch Mustinka River near Charlesville, MN
05048500  West Branch Mustinka River below Mustinka Ditch near Charlesville, MN
05049000  Mustinka River above Wheaton, MN
05050000  Bois de Sioux River near White Rock, SD

05050500  Bois de Sioux River near Fairmont, ND
05051000  Rabbit Creek at Campbell, MN
05051500  Red River of the North at Wahpeton, ND
05051522  Red River of the North at Hickson, ND
05051600  Wild Rice River near Rutland, ND

05051700  Wild Rice River near Cayuga, ND
05053000  Wild Rice River near Abercrombie, ND
05054000  Red River of the North at Fargo, ND
05054500  Sheyenne River above Harvey, ND
05055000  Sheyenne River near Harvey, ND

05055100  North Fork Sheyenne River near Wellsburg, ND
05055200  Big Coulee near Maddock, ND
05055500  Sheyenne River at Sheyenne, ND
05056000  Sheyenne River near Warwick, ND
05057000  Sheyenne River near Cooperstown, ND

05057200  Baldhill Creek near Dazey, ND
05058000  Sheyenne River below Baldhill Dam, ND
05058500  Sheyenne River at Valley City, ND
05058700  Sheyenne River at Lisbon, ND
05059000  Sheyenne River near Kindred, ND

05059500  Sheyenne River at West Fargo, ND
05059600  Maple River near Hope, ND
05059700  Maple River near Enderlin, ND
05060000  Maple River near Mapleton, ND
05060500  Rush River at Amenia, ND

05061000  Buffalo River near Hawley, MN
05061500  South Branch Buffalo River at Sabin, MN
05062000  Buffalo River near Dilworth, MN
05062200  Elm River near Kelso, ND
05062500  Wild Rice River at Twin Valley, MN

05064000  Wild Rice River at Hendrum, MN
05064500  Red River of the North at Halstad, MN
_______________________________________________________________________________

HISTORY OF THE STREAM-GAGING PROGRAM IN NORTH DAKOTA

Much of the history of the stream-gaging program in North Dakota outlined in this report was written by Crosby (1970). However, the number of streamflow-gaging stations given in figure 2 may differ from the number given by Crosby (1970) because the type of gaging stations included may differ. The collection of systematic streamflow data began in 1882 when a gaging station was established on the Red River of the North at Grand Forks. This gaging station was a stage station; however, infrequent discharge measurements were made for navigational purposes. Stage data were obtained on the Missouri River at Bismarck in 1881-82 and in 1886-89 by the Missouri River Commission. As result of the National Reclamation Act of 1902 and the disastrous flood in 1897 in the Red River of the North Basin, the U.S. Geological Survey, in cooperation with the state of North Dakota, established and operated streamflow-gaging stations from 1901-09. Additional interest was created as problems with Canada concerning the division of waters along the international boundary resulted in the formation of the International Joint Commission in 1912. Eight streamflow-gaging stations were in operation in 1925 when State cooperation was discontinued. Only five federally operated gaging stations were continued. State cooperation resumed in 1931, but funds were limited from 1934-38. However, the Rivers and Harbors Act of 1927 and the Flood Control Acts of 1928 and 1936 resulted in the U.S. Army Corps of Engineers supporting a large expansion of the stream-gaging program. Forty-one gaging stations were in operation when the North Dakota-South Dakota U.S. Geological Survey Office was created on October 16, 1944. Plans for the coordinated development of the waters of the Missouri River Basin, with respect to flood control, navigation, power, and irrigation, were formulated in 1943-44 by the U.S. Army Corps of Engineers, the Bureau of Reclamation, and the States in the Basin. These plans resulted in a rapid increase in the stream-gaging program, and, by 1947, 64 gaging stations were in operation. The number of gaging stations grew steadily from the late 1940's until the late 1960's, and, by 1969, 109 gaging stations were in operation.

During 1969-76, the number of gaging stations in operation remained relatively stable. During the 1970's, the U.S. Geological Survey established 25 additional gaging stations to monitor the quantity and quality of streamflow in drainage basins underlain by strippable lignite deposits (Haffield, 1981). By 1979, about 145 gaging stations were in operation in North Dakota. During 1981-83, the number of gaging stations in operation declined rapidly, and, during 1984-87, the number declined slowly to about 110. Since 1987, the number of gaging stations in operation has been relatively stable at about 105 to 110.

EXPLANATION OF STATION SUMMARIES

Station summaries are presented so that each station description and tables of streamflow statistics and probabilities of occurrence are presented in the same order and format for each gaging station, including the same relative placement of the pages. Because the tables were created by "data retrievals" or statistical program results, significant figures were not rounded to U.S. Geological Survey standards. The order of presentation is as follows:

1. manuscript (station description),
2. graph of the annual mean discharge for the period of record,
3. table of statistics of monthly and annual mean discharges,
4. graph of the annual flow duration,
5. table of monthly and annual flow duration,
6. table of probability of annual high discharges,
7. table of probability of annual low discharges,
8. table of probability of seasonal low discharges,
9. table of annual peak discharge and corresponding gage height for the period of record, and
10. table of monthly and annual me an discharges for the period of record.

Where both pre-regulation and post-regulation statistics are presented for a gaging station, the manuscript, graph of annual mean discharges, table of annual peak discharges and corresponding gage heights, and table of monthly and annual mean discharges are presented with the pre- and post-regulation data. The respective tables for the post-regulation data are presented in the same relative page formats.

Manuscripts

The location, drainage area, period of record, and other information about each streamflow-gaging station included in this report are presented in manuscript form. This information is compiled from records maintained by the U.S. Geological Survey and generally is presented in the same format as published in the annual state water report. The following comments clarify information presented under the various headings of the station manuscript.

LOCATION.--Information on gaging station location is obtained from the most accurate maps available and is furnished with respect to cultural and physical features in the vicinity of the gaging station and the community or landmark included in the gaging station name. In the case of discontinued gaging stations, the location is furnished using features in the vicinity at the time the gaging station was in operation. In many instances, the identifying features have been altered since the gaging station was discontinued.

DRAINAGE AREA.--Drainage area is measured using U.S. Geological Survey 7.5-minute topographic quadrangle maps. However, 7.5-minute topographic maps for drainage area computations were not available when some gaging stations were installed; therefore, the accuracy of drainage areas also varies. Drainage areas of discontinued gaging stations are those determined while the gaging station was in operation.

PERIOD OF RECORD.--The period of record is the period for which there are published records for the gaging station or for an equivalent gaging station. An equivalent gaging station is a gaging station that was in operation prior to the subject gaging station, and whose location is such that records from it can reasonably be considered equivalent with records from the subject gaging station. This situation arises when a gaging station is relocated upstream or downstream and given a new gaging station number and name, but the changes in drainage area and other basin characteristics are not significantly different.

GAGE.--The type of gage or recorder that is or was used to collect data, the datum of the gage referred to sea level, and a condensed history of the types, locations, and datums of previous gages are given under this heading.

EXTREMES FOR PERIOD OF RECORD.--Extremes may include maximum and minimum discharges and maximum and minimum gage heights. Unless other wise qualified, the maximum discharge is the instantaneous maximum corresponding to the highest gage height that occurred. If the maximum gage height did not occur on the same day as the maximum discharge, it is listed separately. Similarly, the minimum discharge is the instantaneous minimum corresponding to the lowest gage height that occurred, unless qualified and listed otherwise.

EXTREMES OUTSIDE PERIOD OF RECORD.--Included is any information available concerning major floods or unusually low flows that occurred outside the stated period of record. The information may not have been obtained by the U.S. Geological Survey.

Statistics of Monthly and Annual Mean Discharges

Statistics of monthly and annual mean discharges presented for each gaging station include (1) the maximum, minimum, and mean monthly discharges and (2) the maximum, minimum, and mean annual discharges. The water years (October 1 through September 30) in which the maximum and minimum discharges occurred are listed with the respective values, and the standard deviation and coefficient of variation of the monthly and annual mean discharges are listed with the respective values. Also, the percentage of the annual discharge that is comprised by each monthly mean discharge is listed in the table.

Each of the statistics is explained in the following paragraphs. As an aid to the readers' understanding of how the monthly mean and annual mean discharges are determined, data for the gaging station Otter Tail River near Detroit Lakes, MN (05053000) are used as an example. Each monthly value is the mean of the daily values for the month. Months or years for which all daily values are not available are not included in the compilation of statistics.

The maximum monthly mean discharge is the maximum value of all the monthly mean values. The maximum mean value for October is 138 cubic feet per second (ft3/s), which occurred during water year 1945. Similarly, the minimum monthly mean discharge is the minimum value of all the monthly mean values. The minimum mean value for October is 2.16 ft3/s, which occurred during water year 1957. The maximum and minimum monthly mean values can be found in the statistics of monthly and annual mean discharges table or by searching the monthly and annual mean discharges table.

The mean monthly discharge is the mean of all the monthly mean discharges for a given month, and the standard deviation is a measure of the variability of the values. The mean monthly discharge for October is 29.2 ft3/s, and the standard deviation is 28.9 ft3/s. The monthly mean discharge for October (mean of the mean monthly values) is the same as the mean of all October daily values for the period of record used. However, the standard deviation is smaller than the standard deviation obtained using all daily values. The standard deviation is smaller because the monthly values have less variability than the daily values.

The coefficient of variation is the ratio of the standard deviation to the mean, and it provides a comparison of the standard deviation in units of the mean. The coefficient of variation is dimensionless. Because monthly mean discharges are much greater in spring than in winter, the standard deviations also are much greater in spring than in winter. However, dividing the standard deviation by the mean monthly discharge tends to equalize the measures for all months so a more meaningful comparison among months can be made.

The percentage of the annual discharge is the percent of the annual discharge that occurred during each month. It is calculated by dividing the mean discharge for the month by the total of the 12 monthly mean discharges and multiplying by 100. Because of rounding of the monthly percentage, the sum of the 12 percentages may not equal 100 percent.

The maximum, minimum, and mean annual discharges are selected or computed from the annual mean discharges for the period of record. The water years of occurrence of the maximum and minimum values are listed with the respective values, and the standard deviation of the mean of the annual mean values is listed with the mean value. The minimum annual mean discharge of 9.82 ft3/s occurred in 1940, and the maximum annual mean discharge of 98.4 ft3/s occurred in 1966. The mean annual discharge for the period of record is 53.7 ft3/s.

Monthly and Annual Flow Duration

The monthly and annual flow duration table is a magnitude and frequency analysis of daily discharge values. It is computed by tabulating the number of daily discharge values that fall within preselected class limits, computing the percentage of values within each class, and interpolating discharge values for the percentages shown in the table. Monthly values are calculated from daily values in all complete months in the record, and annual figures are calculated for all complete water years. For example, if the 90-percent flow duration value for October is 2.80 ft3/s, then 90 percent of all October daily discharge values for the period of record were equal to or greater than 2.80 ft3/s.

Probability of Occurrence of High or Low Discharges

The probabilities of occurrence of annual high discharges, annual low discharges, and seasonal low discharges are presented in three tables for each gaging station. Probability of occurrence is an estimate of the likelihood that a particular discharge in a stream will be equaled or exceeded in 1 year or, in the case of low flows, the likelihood that the discharge will not be equaled or exceeded during the year. The probability of occurrence of a high flow is called the exceedance probability, and the probability of occurrence of low flow is called the nonexceedance probability. For example, if the discharge for the 0.20 exceedance probability is listed as 255 ft3/s, then a 20 percent chance exists that a discharge equal to or greater than 255 ft3/s will occur once during the year.

Recurrence interval is another way of expressing annual probability and it is the reciprocal of probability of occurrence. The recurrence interval for an exceedance probability of 0.20 is 5 years (1 divided by 0.20). For a long discharge record the annual maximum discharges can be expected to equal or exceed 255 ft3/s on average once every 5 years.

The table of probability of annual high discharges for each gaging station lists the maximum instantaneous discharge and the maximum mean discharge for 3, 7, 15, and 30 consecutive-day periods for selected exceedance probabilities and recurrence intervals. Values for the maximum instantaneous discharge are computed from the streamflow record according to the guidelines established by the Hydrology Sub committee of the Interagency Advisory Committee on Water Data (1982). According to the guidelines, adjustments are made for length of record and regional skew.

Values for the maximum mean discharges for 3, 7, 15, and 30 consecutive-day periods are computed from the annual high mean values of the corresponding periods. The computations are based on the log-Pearson Type III distribution using values obtained for the water year.

The table of probability of annual low discharges for each gaging station lists the minimum mean discharge for 1, 3, 7, 14, 30, 60, 90, 120, and 183 consecutive-day periods for selected nonexceedance probabilities and recurrence intervals. Values for the minimum mean discharges are computed from the annual low discharge values of the corresponding periods using the log-Pearson Type III distribution. If the log-Pearson Type III distribution curve fails to fit the data at the lower end, a graphical interpretation is made. Probabilities of annual low discharges are computed using values obtained for the climatic year (April 1 through March 31).

The table of probability of seasonal low discharges for each gaging station lists the minimum mean discharge for 1, 7, 14, and 30 consecutive-day periods for selected probabilities and recurrence intervals. These values are computed from the seasonal low mean values of the corresponding periods using the log-Pearson Type III distribution.

The annual low discharge and the seasonal low discharges that occur in any given year are sensitive to natural-channel processes, such as evapotranspiration and human-induced hydrologic modifications, such as the operation of many small water-storage reservoirs; the effects of surface-water withdrawal for agricultural, municipal, and industrial use; and the effects of return flow to the river. Thus, the statistics in tables are given for recurrence intervals that generally are within twice the period of record.

DATA CONSIDERATIONS

Period of Record

The reliability of statistical data is related to the length of record for a stream. The Hydrology Subcommittee of the Interagency Advisory committee on Water Data (1982) recommends that at least 10 years of record be used for computing flood frequency estimates. Therefore, the length of record criterion for inclusion of a gaging station in this report is at least 10 years. Even with this criterion, the lengths of record for each gaging station varies substantially. Subsequently, extreme high or low flows may be included in the streamflow record of one gaging station and not in another, resulting in inconsistencies in the streamflow statistics when comparing gaging station data. Also, longer record lengths for many of the gaging stations in this report may result in different streamflow statistics when comparing data in this report with data in previous publications.

Differences in statistical data for pre- and post-regulation periods are not caused solely by regulation. Differences can be attributed to the length of record and climatic variability as expressed by hydrologic variability. By comparing a statistic that easily can be affected by regulation, such as the 7-day low flow, and a statistic that generally is unaffected by regulation, such as the mean annual discharge, a determination can be made about the effect of regulation. As an example, the annual 7-day low flow with a 10-year recurrence interval for the Red River of the North at Fargo is zero for the pre-regulation period (1901-41) and 17.9 ft3/s for the post-regulation period (1942-94). The effect of regulation on the mean annual discharge of the Red River of the North can be assumed to be negligible; however, the mean annual discharge is 403 ft3/s for the pre-regulation period and 741 ft3/s for the post-regulation period. Although annual 7-day low flow for a 10-year recurrence interval is much greater for the regulation period, the mean annual discharge for the regulated period also is much greater, indicating that regulation may happen to correspond to a relatively wet period in the Red River of the North Basin.

REFERENCES

Crosby, O.A, 1970, A proposed streamflow data program for North Dakota: U.S. Geological Survey Open-File Report, 68 p.
Haffield, N.D., 1981, Statistical summaries of streamflow and water-quality data for streams of western North Dakota, 1977-80: U.S. Geological Survey Open-File Report 81-1066, 78 p.
Hydrology Subcommittee of the Interagency Advisory Committee on Water Data, 1982, Guidelines for determining flood flow frequency: Hydrology Subcommittee Bulletin 17B, 28 p., 14 appendices.
Wahl, K.L., Thomas, W.O., Jr., and Hirsch, R.M., 1995, Stream-gaging program of the U.S. Geological Survey: U.S. Geological Survey Circular 1123, 22 p.

For more Information Contact:

District Chief
821 East Interstate Avenue
Bismarck, ND 58503
Phone: (701)250-7400
Fax: (701)250-7492
Office hours: 8:00 a.m. to 5:00 p.m. CST

For more information on all USGS
reports and products (including maps,
images, and computerized data), call
1-888-ASK-USGS.

Additional earth science information
can be found by accessing the USGS
Home Page on the World Wide Web at http://www.usgs.gov

Inquire on this report: Gregg J. Wiche

Click to Return to Table of Contents

Click to Return to North Dakota Home Page

 


U.S. Department of the Interior || U.S. Geological Survey
Maintainer: Webmaster
Last update: Tuesday, 31-Aug-2004 11:43:27 EDT
Privacy || Disclaimer|| Accessibility || FOIA
URL: http://nd.water.usgs.gov/pubs/ofr/ofr97416/index.html
FirstGov, "Your First Click to the U.S. Government"