Link to USGS home page
Modified from "Surface Water" by Kirk A. Miller in Zelt, R.B., Boughton, G.K., Miller, K.A., Mason, J.P., and Gianakos, L.M., 1999, Environmental setting of the Yellowstone River Basin, Montana, North Dakota, and Wyoming: U.S. Geological Survey Water-Resources Investigations Report 98-4269, 112 p. (online version)
Hydrography and selected streamflow-gaging stations, Yellowstone River Basin
Figure 12. Hydrography and selected streamflow-gaging stations, Yellowstone River Basin.
(Click on image for a larger version, 79KB)

Droughts

Severe droughts of several-years duration have occurred in the Yellowstone River Basin (YRB). Droughts with recurrence intervals greater than 25 years occurred during the periods 1929-42 and 1948-62 over most of Wyoming and Montana (Druse, 1991; Merritt and others, 1991), including nearly all of the YRB. Such regional drought conditions are common in the upper parts of the Missouri River Basin (Matthai, 1979). Droughts with recurrence intervals of 10 to 25 years occurred in the YRB between 1976 and 1982. Recent data for representative streamflow-gaging stations in the basin used in previous drought analyses by Druse (1991) and Merritt and others (1991) indicate lower than normal flows from about 1987 to about 1994 (table 4).

Table 4. Annual departure from mean annual discharge at selected streamflow-gaging stations, Yellowstone River Basin, water years 1987-96 (Modified from U.S. Geological Survey, 1997c)

[06191500 (2), station number and (reference number, fig. 12); --, no data]

Water year

Annual departure from mean annual discharge, in percent

06191500
(2)

06214500
(6)

06225500
(11)

06317000
(42)

06318500
(43)

06324500
(44)

1987

-32.5

-30.3

-11.4

21.7

-2.6

7.2

1988

-36.4

-36.4

-31.2

-43.8

-33.5

-40.2

1989

-9.8

-11.1

-22.1

-53.5

-22.5

-64.7

1990

-3.6

-10.3

-14.2

-31.6

6.3

-22.0

1991

3.0

4.2

10.2

-12.9

31.9

8.4

1992

-11.1

-9.5

-32.9

-39.5

31.7

-23.0

1993

11.9

9.0

-16.3

36.3

--

29.1

1994

-22.6

-30.3

-34.4

-34.1

--

-31.2

1995

6.9

12.6

4.7

130

--

75.9

1996

45.4

38.6

12.5

-8.8

--

2.1

The drought of 1977 affected most of the United States west of the Mississippi River (Matthai, 1979). In the YRB, the 1977 drought was part of the 1976-82 drought period; the most severely affected areas were the upper parts of the Wind and Yellowstone River watersheds (Druse, 1991; Merritt and others, 1991). Decreased streamflows during droughts can result in higher dissolved-solids concentrations. Median concentrations of total dissolved solids in samples collected during September through the following February of each year (that is, the period of year during which flows are lower) were significantly higher (Wilcoxon rank-sum test; p < 0.05) during the drought period 1976-82 than during non-drought years at sites 3 and 6 on the upper Yellowstone River (table 5). Dissolved-solids concentrations were higher during the 1976-82 drought than during non-drought periods at site 12 on the Wind River; however, the difference was not significant (table 5). Site 12 might not be representative of drought conditions in the upper parts of the Wind River watershed because of flow modifications upstream of the site.

Table 5. Statistics for total dissolved-solids concentration at selected sites, September-February, during non-drought and drought periods, upper Wind and Yellowstone Rivers, 1969-94

[n, number of analyses; mg/L, milligrams per liter; Y, yes; N, no]

Reference number
(fig. 12)

Station number

Non-drought periods

1976-82 drought

n

Median concentration
(mg/L)

n

Median concentration
(mg/L)

Significance
(p-value)a

3

06192500

60

172

33

183

Y (p=0.0239)

6

06214500

89

272

38

282

Y (p=0.0363)

12

06228000

93

277

37

287

N (p=0.1752)

aWilcoxon rank-sum test for significance; one-sided p value. Higher concentrations of total dissolved solids during the 1976-82 drought are significant at the 95-percent confidence level if p<0.05.


Return to Wyoming Drought Watch.

U.S. Department of Interior, U.S. Geological Survey
Maintainer: Kirk Miller
URL: http://wy.water.usgs.gov/projects/drought/html/yrb_droughts.html