FLOOD ANALYSIS ALONG THE LITTLE MISSOURI RIVER WITHIN … · 2010-12-22 · FLOOD ANALYSIS ALONG THE LITTLE MISSOURI RIVER WITHIN AND ADJACENT TO THEODORE ROOSEVELT NATIONAL PARK,

FLOOD ANALYSIS ALONG THE LITTLE MISSOURI RIVER WITHIN AND

ADJACENT TO THEODORE ROOSEVELT NATIONAL PARK, NORTH DAKOTA

By Douglas G. Emerson and Kathleen M. Macek-Rowland

Water-Resources Investigations Report 86-4090

Prepared in cooperation with the

NATIONAL PARK SERVICE

Bismarck, North Dakota

1986

UNITED STATES DEPARTMENT OF THE INTERIOR

DONALD PAUL HODEL, Secretary

GEOLOGICAL SURVEY

Dallas L. Peck, Director

For additional information write to:

District Chief, WRD U.S. Geological Survey 821 East Interstate Avenue Bismarck, ND 58501

Copies of this report can be purchased from:

Open-File Services Section Western Distribution Branch U.S. Geological Survey Box 25425, Federal Center Denver, CO 80225 (Telephone: (303) 236-7476)

CONTENTS

Page.

Abstract 1Introduction 1Flood frequency 3Flood profiles 1 2Ice jams 14Flood-hazard assessment 33Summary 35References 36

ILLUSTRATIONS

Figure 1. Map showing location of Theodore RooseveltNational Park 2

2. Map showing South Unit study reach and locationof cross sections A-A 1 through R-R 1 4

3. Map showing Elkhorn Ranch Site study reach andlocation of cross sections S-S 1 through V-V 5

4. Map showing North Unit study reach and locationof cross sections W-W 1 through FF-FF 1 6

5. Graphs showing relation between the 100- and 500-year flood discharges and drainage area for the Little Missouri River 9

6. Cross sections A-A 1 through L-L 1 and water-surface elevations for 100- and 500-year floods, Little Missouri River, South Unit reach 15

7. Cross sections M-M 1 through O-O' and water-surface elevations for 100-year flood, Knutson Creek reach 19

8. Cross sections P-P 1 through R-R 1 and water-surface elevations for 100-year flood, Paddock Creek reach 20

9. Cross sections S-S 1 through V-V and water-surface elevations for 100- and 500-year floods, Little Missouri River, Elkhorn Ranch Site reach 21

10. Cross sections W-W through CC-CC 1 and water- surface elevations for 100- and 500-year floods, Little Missouri River, North Unit reach 23

11. Cross sections DD-DD 1 through FF-FF 1 and water- surface elevations for 100-year flood, Squaw Creek reach 26

12. Profiles for 100- and 500-year floods and streambed, Little Missouri River, South Unit reach 27

111

ILLUSTRATIONS, Continued

Figure 13. Profiles for 100-year flood and streambed,Knutson Creek reach 28

14. Profiles for 100-year flood and streambed,Paddock Creek reach 28

15. Profiles for 100- and 500-year floods andstreambed, Little Missouri River, ElkhornRanch Site reach 29

16. Profiles for 100- and 500-year floods and streambed, Little Missouri River, North Unit reach 30

17. Profiles for 100-year flood and streambed,Squaw Creek reach 31

18. Graphs showing relation between backwater due to ice and water-surface elevations, and an envelope curve 32

19. Graphs showing water-surface elevation-frequencycurves 34

Table

3.

TABLES

Annual peak discharges and annual maximum water-surface elevations for the streamflow station Little Missouri River at Medora (06336000) -

Annual peak discharges and annual maximum water-surface elevations for the streamflow station Little Missouri River near Watford City (06337000) -

Flood discharges for selected reaches -1013

SELECTED FACTORS FOR CONVERTING INCH-POUND UNITS TO

THE INTERNATIONAL SYSTEM (SI) OF UNITS

For those readers who may prefer to use the International System (SI) of Units rather than inch-pound units, the conversion factors for the terms used in this report are given below.

Multiply inch-pound unit By To obtain SI unit

Cubic foot per second

(ft3/s)

Foot (ft)

Mile (mi)

Square mile

0.02832

0.3048

1.609

2.590

cubic meter per

second

meter

kilometer

square kilometer

National Geodetic Vertical Datum of 1929 (NGVD of 1929): A geodetic datum derived from a general adjustment of the first-order nets of both the United States and Canada, formerly called "mean sea level." NGVD of 1929 is referred to as sea level in this report.

FLOOD ANALYSIS ALONG THE LITTLE MISSOURI RIVER WITHIN AND

ADJACENT TO THEODORE ROOSEVELT NATIONAL PARK,

NORTH DAKOTA

By Douglas G. Emerson and Kathleen M. Macek-Rowland

ABSTRACT

The Little Missouri River flows through Theodore Roosevelt National Park t which consists of three separate units: South Unit, Elkhorn Ranch Site, and North Unit. The park is located in the Little Missouri badlands. Discharges and water-surface elevations for 100- or 500-year floods or both were computed for selected reaches along the Little Missouri River and three of its tribu taries (Knutson Creek, Paddock Creek, and Squaw Creek) within and adjacent to Theodore Roosevelt National Park. The 100- and 500-year flood discharges for the Little Missouri River were determined from streamflow records. The 100-year flood discharges for the three creeks were estimated using a multiple-regression equation based on drainage area and soil-infiltration index. Water-surface elevations were determined by the step-backwater method. The effects of ice jams on water-surface elevations were estimated from streamflow records.

INTRODUCTION

Theodore Roosevelt National Park an area of geologic, historic, and scenic interest is located in western North Dakota (fig. 1) in the Little Missouri badlands. The park consists of three separate units: South Unit, Elkhorn Ranch Site, and North Unit. The Little Missouri River, a tributary of the Missouri River, flows north through the South Unit and Elkhorn Ranch Site and then turns in the North Unit and flows east. The Little Missouri badlands are described by Bluemle (1977) as a "Rugged, deeply-eroded, hilly area along the Little Missouri River; gentle slopes characterize 20 to 50 percent of the area and local relief is commonly over 500 feet."

The National Park Service needed information on flood potential as part of a general management plan for the park. They requested and funded a study to determine water-surface elevations along the Little Missouri River and three of its tributaries (Knutson Creek, Paddock Creek, and Squaw Creek) within and adjacent to Theodore Roosevelt National Park. The water-surface elevations will be used by the National Park Service as a basis for planning visitor activities and selecting structure sites*

The objectives of the study were to: (1) Determine water-surface eleva tions for 100- and 500-year flood discharges for selected reaches of the Little Missouri River; (2) determine water-surface elevations for 100-year

4800' -

4700" -

NORTH DAKOTA

SOUTH DAKOTA

Theodore Roosevelt National Park (North Unit)

KENZIECQ BILLINGSTXX

Theodore RooseveltNational Park

(Elkhorn Ranch Site)

Theodore Roosevelt National Park (South Unit)

10400' 10300'Base modified from U.S. GeologicalSurvey Theodore RooseveltNational Memorial Park, 0 5 10 15 20 25 MILESN. Dak. (South Unit), 1974 I r H H , h ' '

0 5 10 15 20 25 KILOMETERS

Figure 1. Location of Theodore Roosevelt National Park.

flood discharges for the areas near the mouths of Knutson, Paddock, and Squaw Creeks; and (3) evaluate the effects of ice jams on water-surface elevations.

The study reach for the South Unit (fig. 2) is about 8 river miles long and includes the area along the Little Missouri River from about 0.1 mi south of Medora to about 1 mi downstream from Beef Corral Bottom. The study reach for the Elkhorn Ranch Site (fig. 3) is about 3 river miles long and includes the area from about 0.5 mi south of the south boundary of the site to about 0.05 mi north of the north boundary of the site. The study reach for the North Unit (fig. 4) is about 7 river miles long and includes the area from about 1 mi upstream from Squaw Creek Campground to the bridge on U.S. Highway 85.

FLOOD FREQUENCY

The annual peak discharge data for the streamflow station Little Missouri River at Medora (06336000), which has a drainage area of about 6,190 mi^, were used to determine the 100- and 500-year flood discharges for the Little Missouri River along the South Unit reach. The flood discharges determined are considered to be applicable for the entire South Unit reach. The pro cedures described by the U.S. Geological Survey (1982) were used to determine flood-flow frequency. The station has a discontinuous record from May 1903 to September 1934 and a continuous record from October 1945 to September 1976. The records include 50 annual peak discharges and 50 annual peak elevations (table 1).

Discharge data are not available for the Little Missouri River near the Elkhorn Ranch Site reach. Therefore, annual peak discharge data for the streamflow stations Little Missouri River at Marmarth (06335500), Little Missouri River at Medora (06336000), and Little Missouri River near Watford City (06337000) were used to determine the 100- and 500-year flood discharges for these stations. The 100- and 500-year flood discharges determined at these stations were then plotted against the station drainage areas (fig. 5) and a curvilinear line drawn through the points. The 100-year flood discharge for the Little Missouri River near the Elkhorn Ranch Site reach, which has a drainage area of about 6,680 mi^, was determined from the plot to be 69,000 ft-Vs, and the 500-year discharge was determined from the plot to be 103,000 ft-^/s. Flood discharges determined in this analysis are considered to be applicable for the entire Elkhorn Ranch Site reach.

The annual peak discharge data for the streamflow station Little Missouri River near Watford City (06337000), which is located near the downstream end of the North Unit and has a drainage area of about 8,310 mi^, were used to determine the 100- and 500-year flood discharges for the Little Missouri River along the North Unit reach. Flood discharges determined in this analysis are considered to be applicable for the entire North Unit reach. The station has a continuous record from September 1934 to the present. The record includes 48 annual peak discharges and 48 annual peak elevations (table 2).

Discharge data are not available for Knutson and Paddock Creeks, which are located in the South Unit (fig. 2), or for Squaw Creek, which is located in

141 N.

R. 14O N. R. 14O N.

Base modified from U.S. Geological Survey Belfield. 1980

R. 1O2 W. R.101 W.

3 MILES

3 KILOMETERS

CONTOUR INTERVAL G5.6 FEET NATIONAL GEODETIC VERTICAL DATUM OF 1929

G-G'

EXPLANATION

CROSS SECTION

PARK BOUNDARY

Figure 2. South Unit study reach and location of cross sections A-A' through R-R'.

47°15'00" 103°37'30" R. 102 W.^

Base modified from U.S. Geological Survey Roosevelt Creek West, 1974base moamed trom u.b. ue Roosevelt Creek West, 1974 Roosevelt Creek East, 1970

0h 0

R. 102 W.

1 MILE

V4 Vz 1 KILOMETER

CONTOUR INTERVAL 20 FEET NATIONAL GEODETIC VERTICAL DATUM OF 1929

EXPLANATION

S-S' CROSS SECTION

- - PARK BOUNDARY

Figure 3. Elkhorn Ranch Site study reach and location of cross sections S-S'.through V-V.

R. 100 W. 10320'00" R. 99 W. 103 15'00"

T.148 N.

T. 147 N.

R.100 W.Base modified from U.S. Geological Survey Watford City, 1982

R. 99 W.

3 MILES

0123 KILOMETERS

CONTOUR INTERVAL 65.6 FEET NATIONAL GEODETIC VERTICAL DATUM OF 1929

W-W

EXPLANATION

CROSS SECTION

- PARK BOUNDARY

Figure 4. North Unit study reach and location of cross sections W-W through FF-FF'.

Table 1 . Annual peak discharges and annual maximum water-

surface elevations for the streamflow station

Little Missouri River at Medora (06336000)

DatePeak discharge

(cubic feet per second)

Maximumwater-surface

elevation(feet abovesea level)

JuneJulyJuneJuneJune

MayMar.MayJulyApr.

JuneMar.Apr.JuneFeb.

SeptJuneApr.MayJune

JuneMar.Mar.Mar.Mar.

Apr.Mar.Apr.Apr.June

9,2,8,246,

31,16

17,8,3,

16164,7,25

. 12228

24,12

2423232127

8,221,8,21

190419051906

, 19071908

1909, 1910191119121914

, 1915, 191619241929

, 1930

3, 1930, 1931, 19321933

, 1934

, 1946, 1947, 1948, 1949, 1949

1950, 195119521952

, 1953

118

132910

127551

246

1838

41

1220

1

96524

14

255

428

,600,500,900,000,800

,400,550,540,750,850

,700,630,500,700

,700,610,500,800,850

,310,000,100 ,600

,600,200

,500,820

22222

22222

22222

2222

2222

222

2

i,iif

iiiii

itiii

iiti

itii

tii

i

257256258262257

258256255255253

260255260263255

251256259251

255267260259

-

259255265

-254

.95

.95

.75

.75

.45

.25

.25

.35

.45

.05

.75

.85

.55

.95

.15

.27

.41

.19

.25

.50

.25

.25

.75-

.75

.75

.10-.96

Table 1. Annual peak discharges and annual maximum water-

surface elevations for the streamflow station Little

Missouri River at Medora (06336000) Continued

DatePeak discharge



elevation(feet abovesea level)

Apr. 7, 1954June 27, 1955Mar. 20, 1956Mar. 27, 1956June 22, 1957

July 4, 1958Mar. 20, 1959Mar. 22, 1960May 24, 1961May 30, 1962

Mar. 3, 1963June 10, 1964Apr. 3, 1965Mar. 14, 1966May 11, 1 967

Mar. 7, 1968Mar. 23, 1969May 9, 1970June 6, 1971Mar. 11, 1972

Mar. 1, 1973June 20, 1973May 21, 1974May 9, 1975June 21, 1976

4,32025,600

2,0307,900

5,0506,6508,1003,540

10,800

11,0009,17015,0006,80015,700

3,00011,2006,550

21,20040,000

3,8205,230

22,8006,000

2,252.742,260.652,251.51

2,254.20

2,252.652,254.222,255.472,251.972,256.60

2,261 .052,255.862,259.302,254.732,258.48

2,252.102,256.752,254.062,259.572,265.43

2,254.45

2,253.652,260.752,253.81

I/)LJ

o: <Z)a

9000

8000

7000

6000

5000

4000

100-YEAR FLOOD

UTTLE MISSOURI RIVER NEAR WATFORD CITY \ (06337000)

'ESTIMATED DISCHARGE OF UTTLE MISSOURI RIVER ~ FOR ELKHORN RANCH SITE REACH

UTTLE MISSOURI RIVER AT MEDORA (06336000)

UTTLE MISSOURI RIVER AT MARMARTH (06335500)

40.000 50.000 60.000 70.000 80.000FLOOD DISCHARGES. IN CUBIC FEET PER SECOND

0.000

<LJa:

LJo

Q

9000

8000

7000

6000

5000

4000

LITTLE MISSOURI RIVER NEAR WATFORD CITY (06337000)

500-YEAR FLOOD

ESTIMATED DISCHARGE OF UTTLE MISSOURI RIVER FOR ELKHORN RANCH SITE REACH

UTTLE MISSOURI RIVER AT MARMARTH (06335500) UTTLE MISSOURI RIVER AT

MEDORA (06336000)

70.000 80.000 90.000 100.000 110.000

FLOOD DISCHARGES. IN CUBIC FEET PER SECOND120.000

Figure 5. Relation between the 100- and 500-year flood discharges and drainage area for the Little Missouri River.



Missouri River near Watford City (06337000)


elevation(feet above

Date (cubic feet per second) sea level)Peak discharge


JulyMar.JuneMar.Mar.

SeptJuneMar.Feb.Apr.

Mar.Feb.Mar.Mar.Mar.

Mar.Apr.Mar.Mar.Apr.

Mar.JuneJuneJuneJuly

JuneMar.Mar.Mar.May

1110151522

iiitt

. 231111228,

1424251724

289,252710

2522142830

23252022

24,

iit

tiiii

i

iti

iitii

iiit

19351936193719381939

, 19401941194219431944

19451946194719481948

19491950195119511952

19531953195419551956

1957195819591960

1961

2088

1426

413122532

308

110

16

2660

1842

710172

61212182

iiii

iti,t

tii

i

tt

ii

iiit

tiiti

500800990600500

270000600000600

000000000

000

000000 000000

.-

650200600770

890000800900920

11111

11111

1111

111

1

1

111

11111

,939,937,936,938,942

,935,938,938,947,943

,943,937,953,943

-

,942,950,942

-

,944

,937-

,937,938,935

,936,938,939,938,932

.63

.03

.88

.43

.08

.86

.03

.62

.03

.43

.43

.78

.03

.63-

.73

.45

.97-

.56

.58-

.40

.99

.03

.83

.97

.16

.86

.79

10



Missouri River near Watford City (06337000) Continued

Date

May 31, 1962Mar. 5, 1963July 5, 1964Apr. 8, 1965Apr. 10, 1965

Mar. 12, 1966Mar. 22, 1967Mar. 1, 1968Mar. 23, 1969May 9, 1970

Mar. 28, 1971Mar. 13, 1972Feb. 28, 1973Feb. 2, 1974May 21, 1974

May 11, 1975Mar. 19, 1976June 24, 1976June 17, 1977Mar. 30, 1978

Mar. 18, 1979Apr. 17, 1979Mar. 23, 1980June 14, 1980Oct. 23, 1980

Feb. 18, 1981Feb. 21, 1982Mar. 13, 1982

Peak discharge (cubic feet per second)

12,10010,00012,000

20,000

12,00030,0007,90015,30013,400

31,00052,8007,500

6,750

17,500

7,6006,40031,500

10,000 865

1,390

11,000

__

Maximum water-surface

elevation (feet above sea level)

1,935.741,938.931,936.851,946.96

1,936.361,945.101,935.411,937.071,936.33

1,944.301,943.711,935.451,935.33

1,937.431,938.42

1,934.431,940.11

1,935.70

1,932.84

1,933.31

1,942.06

11

the North Unit (fig. 4). The 100-year flood discharges were estimated using a multiple-regression equation based on drainage area and soil-infiltration index (O. A. Crosby, U.S. Geological Survey, written commun., 1984). The equation,

Q100 = 927A°- 65Si-1 - 00 ,

where Q-joo = t-*16 1 00-year flood discharge, in cubic feet per second;A = the drainage area, in square miles; and

Si = the soil infiltration index, in inches;is based on 47 streamflow stations with most of the stations having 18 years of record. The average standard error of estimate is 98 percent.

A summation of the 100- and 500-year flood discharges for the Little Missouri River and the 100-year flood discharges for the three creeks is listed in table 3. The 100-year flood discharges on the Little Missouri River range from 65,300 to 78,800 ft3 /s, whereas the 500-year flood discharges range from 99,300 to 113,500 ft3/s. The 100-year flood discharges on the three creeks range from 18,500 to 31,800 ft3 /s.

FLOOD PROFILES

The water-surface profiles for the flood discharges listed in table 3 for the various reaches were computed using the U.S. Geological Survey's E431 program (Shearman, 1976). The program computes water-surface profiles for gradually varied, subcritical flow by the step-backwater method. The computations that were used to define water-surface elevations are based on hydraulic equations that depend on the following assumptions: (1) Stream discharge remains constant in the subreach defined by the two cross sections; (2) the flow regime in the subreach is entirely critical, critical and subcritical, or subcritical; (3) the longitudinal water-surface and channel slopes are small enough that normal depths and vertical depths may be con sidered equal; (4) the water surface is level across each individual cross section; (5) effects from sediment and air entrainment are negligible; and (6) all losses are correctly evaluated.

Starting elevations for downstream ends of the South Unit reach, the Elkhorn Ranch Site reach, and the three creeks were obtained using a slope- conveyance technique together with computed 100- or 500-year discharges or both discharges. The starting elevations for the downstream end of the North Unit reach were obtained using the relationship between elevation and discharge for the streamflow station Little Missouri near Watford City (06337000), which is located at the downstream end of the North Unit reach. Gradually varied flow does not exist where the creeks enter the Little Missouri River flood plain. Because of this, the flood profile for the creeks cannot be computed using this method for the area within the Little Missouri River flood plain. The computed flood profiles for the three creeks are for reaches upstream of the Little Missouri flood plain.

Roughness coefficients (Mannings Hn H ) used in the computations were chosen from experience and by using results of coefficient-verification studies by Barnes (1967). Limited cross-sectional data were obtained from field surveys.

12

Table 3. Flood discharges for selected reaches

Reach

Recurrence interval (years)

Probability (percent)

Discharge(cubic feet per

second)

Little Missouri River South Unit

Little Missouri River Elkhorn Ranch Site

Little Missouri River North Unit

Knutson Creek

Paddock Creek

Squaw Creek

100500

100500

100500

100

100

100

1 0.2

1 0.2

1 0.2

1

1

1

65,30099,300

69,000103,000

78,800113,500

31,800

18,500

24,600

13

The locations of the field-surveyed cross sections are shown in figures 2-4. These cross sections and computed water-surface elevations for the various reaches are shown in figures 6-11. Limited resources dictated the number of field-surveyed cross sections. Additional intermediate cross sections required for computational purposes were synthesized from the field-surveyed data and topographic maps. The average velocities for the 100-year flood for the Little Missouri River are about 4.8 ft/s for the South Unit reach, 4.9 ft/s for the Elkhorn Ranch Site reach, and 3.6 ft/s for the North Unit reach. The average velocities for the 500-year flood are about 0.2 ft/s higher than the average velocities for the 100-year flood. The average velocities for the 100-year floods on the three creeks are about 7.8 ft/s for Knutson Creek, 4.6 ft/s for Paddock Creek, and 6.6 ft/s for Squaw Creek. The flood profiles of the various reaches are shown in figures 12-17. The average water-surface slope for the floods on the Little Missouri River is about 0.0005 ft/ft, and the difference between the 100- and 500-year flood elevations averages about 3.5 ft.

ICE JAMS

"An ice jam may be defined as an accumulation of ice in a stream which reduces the cross sectional area available to carry the flow and increase the water-surface elevation. The accumulation of ice is usually initiated at a natural or manmade obstruction or a relatively sudden change in channel slope, alignment, or cross section shape or depth. In northern regions of the United States, where rivers can develop relatively thick ice covers during the winter, ice jamming can contribute significantly to flood hazards. When historical records are examined, ice jams are typically found to occur in the same locations. This is because the necessary conditions for genesis of an adequate ice supply and obstruction of its downstream transport determine the specific areas where ice jams will occur." (Federal Emergency Management Agency, 1982, p. A 3-1).

An analysis of ice jams is subjective. The Little Missouri River at Medora (06336000) and the Little Missouri River near Watford City (06337000) are the only streamflow stations having data available for analysis. The backwater due to ice versus the water-surface elevations for discharge measurements was plotted for these two stations (fig. 18). All discharge measurements for the Little Missouri River at Medora (06336000) were used to develop a maximum observed backwater envelope curve. Cross section C-C' of the Little Missouri River, South Unit reach, is located at this site. From September 1934 to October 1959, the streamflow station Little Missouri River near Watford City (06337000) was located about 1 mi upstream from its present location. Only the measurements made during that period were used to develop a maximum observed backwater envelope curve. Cross section AA-AA 1 of the Little Missouri River, North Unit reach, is located about 200 ft upstream from this site. A maximum observed backwater envelope curve was not developed for the present streamflow-station location because of the lack of high-flow measurements.

Although the curves represent only maximum observed backwater and the number of measurements decreases at higher flows, the curves represent a trend

14

A1

2280

2270

2260

2250 -

2240

I 7500-YEAR FLOOD ELEVATION (2276.1 FEET)

100-YEAR FLOOD ELEVATION (2271.9 FEET)

0 200 400 600 800 1000 1200 1400 1600 1BOO 2000

DISTANCE, IN FEET

LJ

<Ul

Ul

O CD

LJ LJ

z o

1

B'

2280

2270

2260 -

2250 -

2240



200 400 600 BOO

DISTANCE, IN FEET

2280

2270

2260

2250

2240

C'

/ / / rv / / / /\/ / / /,RAILROAD IRID6C STRINGERS ,,500-YEAR FLOOD ELEVATION (2273.6 FEET)

,100-YEAR FLOOD ELEVATION (2269.8 FEET)

VERTICAL LINES WITHIN SECTION ARE BRIDGE PIERS

0 200 400 600

DISTANCE, IN FEET

Figure 6. Cross sections A-A' through L-L' and water-surface elevations for 100- and 500-year floods. Little Missouri River, South Unit reach.

15

D'

2280

2270

2260

2250

2240

I l UEOORA BRIDGE STRINGERS

/

V/////////7T7A/500-YEAR FLOOD ELEVATION (2272.0 FEET)



0 200 400 600

DISTANCE, IN FEET

aUI O

o m

ui ui

E'

2280

2270

2260

2250

2240

MO-YEA.R FLOOD ELEVATION f??7l.« FEETi

100-YEAR FLOOD ELEVATION (2267.J FUT)\

-800 -600 -400 -200UI

0 200 400 600DISTANCE, IN FEET

BOO tOOO 1200

izou

2270

2260

2250

it AH

/////////I/////1 ////, INTERSTATE 14 BRIDGE STRINGERS

tT

L. '

\

\ . **

N

7__^---

*


tOO-YEAR FLOOD ELEVATION (2262.2 FEET)


200 400 600 BOODISTANCE. IN FEET

Figure 6. Cross sections A-A' through L-L' and water-surface elevations for 100- and 500-year floods. Little Missouri River, South Unit reach Continued.

16

G'

2270

2260

2250

2240

2230

500-YEAR FLOOD ELEVATION (22*1.7 FEET)


-1000 -800 -COO -400 -200 0 200 400 BOO BOO 1000 1200 1400

DISTANCE, IN FEET

UJ>

<UJ V) UJ

o m

UJu.

z g

ILJ

LJ

H

2270

2260

2250

2240

2230

500-YEAR FLOOD ELEVATION (2251.S FEET)


H'

-600 -400 -200 0 200 400 600DISTANCE, IN FEET

BOO 1000 1200

2270

2260

2250

2240

2230



-400 -200 200 400 600 800 1000 1200 1400 1600 1800

DISTANCE. IN FEET


17

J'

2260

22SO

2240 -

2230 -

2220

MO-YEAR FLOOD ELEVATION Q2»t.4 rctT) 7

-1000 -800 -tOO -400 -200 0 200 400 tOO 100DISTANCE, IN FEET

UJ

LJ

o ffi

UJ UJ

O

IyUJ

K'

2260

2250

2240

2230

2220-400 -200

MO-YEAR FLOOD ELEVATION (2252.4 FEET)

100-YEAR FLOOD ELEVATION (2248.S FEET)

200 400 §00 aoo tooo 1200 MOO DISTANCE, IN FEET

L'

2260

2250

2240

2230

2220

50Q-YCAR FLOOD ELEVATION (2250.5 FEET)


-1600 -1400 -1200 -1000 -800 -600 -400 -200 0DISTANCE, IN FEET

200 400 600


18

MM'

2275

2270

2265

2260

2255

2250


300 400 500 600 700 800 900 1000 1100 1200 1300

DISTANCE, IN FEET

N'

Ld

< Ld

UJ

O CD

I- UJ

2265

2260

2255

2250

2245

2240

I \ I l I I


100 200 300 400 500 600 700DISTANCE. IN FEET

0'

2265

2260

2255

2250

2245

2240

I I I T

100-YEAR FLOOD ELEVATION (22»t.« FEET)

-100 0 100 200 300 400 500

DISTANCE, IN FEET

Figure 7. Cross sections M-M' through O-O' and water-surface elevations for 100-year flood, Knutson Creek reach.

19

2270

22fO -

2250 -

2240 -

2250

ttO-YKA« ruOOO CUVATION (22M.4 rVCYj ^L

-100 0 100 200 500 400DISTANCE. IN FEET

Ul

Ul

<Ul V)

Ul

O ffi

Ul Ul

Ul

Ul

2270

2210

2250

2240

2250-200 -100

Q'

100-YCAR riOOO ELEVATION (2257.7 ftCT)

100 200 500 400 500 COO

DISTANCE. IN FEET700 BOO 900 1000

22CO

2250

2240

R 1

I I i I l

tOO-YEAR riDOD ELEVATION (2251.0

2250-1000 -tOO -BOO -700 -COO -500 -400 -500 -200 -100 0

DISTANCE. IN FEET100 200

Figure 8. Cross sections P-P' through R-R' and water-surface elevations for 100-year flood, Paddock Creek reach.

20

2150

2140

2130

2120UJ

a

Ul> o00

2110

MO-YEAR FLOOD ELEVATION (2U8.1 FEET)

IQQ-YEXft FLOOD ELEVAT10M (2134.S FEET)

S'

-400 -200 200 400 fOO 100 1000 1200

DISTANCE, IN FEET1400 1*00 1800 2000

UJ UJ

z. oIaUJ

2140

21SO

2120

2110

500-YEAR FLOOD ELEVATION (21S5.I FEET)

200 400 fOO 800 1000

DISTANCE, IN FEET1200 1400

Figure 9. Cross sections S-S' through V-V and water-surface elevations for 100- and 500-year floods. Little Missouri River, Elkhorn Ranch Site reach.

21

2140

2130

2120

> UJ

UJ> o ffi

2110

I I I I I T

500-YEAR FLOOD ELEVATION (2134.5 FEET)100-YEAR FLOOD ELEVATION (2131.1 FEET)

U'

-BOO -SOO -400 -200 0 200 400 SOO

DISTANCE, IN FEET800 1000 1200 1400

Ul

2140

2130

2120

2110

2100

I i i i i r

MO-YEAR FLOOD ELEVATION (2132.J FEET)

100-YEAR FLOOD ELEVATION (212J.O FEET)

-200 200 400 SOO 800


Figure 9. Cross sections S-S' through V-V and water-surface elevations for 100- and 500-year floods, Little Missouri River, Elkhorn Ranch Site reach Continued.

22

13A31 V3S 3A08V 133J Nl 'NOLLVA313

Figure 10. Cross sections W-W through CC-CC' and water-surface elevations for 100- and 500-year floods, Little Missouri River, North Unit reach.

23

M

M

13A31 V3S 3A08V 133J Nl 'NOI1VA313

Figure 10. Cross sections W-W through CC-CC' and water-surface elevations for 100- and 500-year floods. Little Missouri River, North Unit reach Continued.

24

AA1970

1960

1950

1940

1 1 1 1 1 1 1 1 1


100 -YEAR FLOOD ELEVATION (1954.3 FEET)

1 1

/

1 1 1 1 1 1 I1930 ________

0 200 400 600 800 1000 1200 1400 1600 1800 20

AA 1

DISTANCE, IN FEET

UJ>

UJ>Om

UJ UJ

UJ_lUJ

BBI960

1950

1940

1930

tatn

\

1 1 1 1 1 1 1


_ ^~~~ ~- -^400-YEAR FLOOD ELEVATI

^^"

-

ON (194B.B FEET) _

-

^ 1 -

1 1 1 1 1 1 1

BB'

200 400 600 800 1000 1200


CC'

1950



VERTICAL LINES WITHIN SECTION ARE BRIDGE PIERS1940 -

1930 -

1920800 1000 1200 1400 1600

DISTANCE, IN FEET

Figure 10. Cross sections W-W through CC-CC' and water-surface elevations for 100- and 500-year floods, Little Missouri River, North Unit reach Continued.

25

1980 100-YEAR FLOOD ELEVATION (1979.9 FEET)

1975

1970 -

1965100 200 300 400 500 600


Ul

OCO

Ul Ulu.

Ul

EE 1

1970 -

1965 -

1960


100 200 300 400 500 600

DISTANCE, IN FEET

FF1980

FF'

1975

1970

1965

1960

1955

100-YEAR FLOOD ELEVATION (1974.6 FECT)

100 200 300 400 500 600

DISTANCE, IN FEET

Figure 11. Cross sections DD-DD' through FF-FF' and water-surface elevations for 100-year flood, Squaw Creek reach.

26

2280

bJ

bJ

bJ (/)

LJ

oCD

LJ LJ

LJ

LJ

2270 -

2260 -

2250 -

2240 -

2230 -

222010.000 20.000 30,000

DISTANCE, IN FEET40,000 50.000

Figure 12. Profiles for 100- and 500-year floods and streambed, Little Missouri River, South Unit reach.

27

2270

Ul

Ul (Si Ul>O m

2260

ui ui u.

2250z"O

1ui_jUl

2240

CROSS SECTIONS

1000 2000DISTANCE, IN FEET

3000

Figure 13. Profiles for 100-year flood and streambed, Knutson Creek reach.

2260

ui

Ul V)

UJ 2250

Om

uiUl

2240z"

O

1

u.

Ul

2230

FV.OOO

CROSS a SECTIONS

" ^ZZZZZZZZZZ1000 2000 3000

DISTANCE, IN FEET4000

Figure 14. Profiles for 100-year flood and streambed. Paddock Creek reach.

28

UJ

LJ

UJ(/)UJ

O00

UJ_J UJ

2140

2130

2120

*f

\

2110

2100

CROSS SECTIONS

2000 4000 6000


Figure 15. Profiles for 100- and 500-year floods and streambed. Little Missouri River, Elkhorn Ranch Site reach.

29

1980

Ld

LJ

t/)LU

O CD

bJ

1970 -

1960 -

1950 -

1940

1930 -

192010.000 20,000 30.000

DISTANCE, IN FEET40.000 50.000

Figure 16. Profiles for 100- and 500-year floods and streambed. Little Missouri River, North Unit reach.

30

1980

LJ

LJ

LJ V)

LJ >oCD

LJ LJ

2«t

2 O h-

LJ

LJ

1970

1960

1950500 1000

DISTANCE. IN FEET1500

Figure 17. Profiles for 100-year flood and streambed, Squaw Creek reach.

31

UJ

LITTLE MISSOURI RIVER AT MEDORA (06336000)

Ld O

2257 2259 2261 2283 2285 2267 2269

ELEVATION, IN FEET ABOVE SEA LEVEL

O

a:Ld

IoCD

LITTLE MISSOURI RIVER NEAR WATFORD CITY (06337000)

/OLD GAGE LOCATION ABOUlA 1 MILE UPSTREAM FROM

^PRESENT SITE )

1938 1940 1942 1944 1946 1948 1950 1952

ELEVATION, IN FEET ABOVE SEA LEVEL1954

Figure 18. Relation between backwater due to ice and water-surface elevations, and an envelope curve.

32

in which the backwater decreases as the discharge increases. For both streamflow stations, the backwater due to ice approaches zero before reaching the elevation computed in the step-backwater computations for the 100-year flood discharge.

The water-surface elevation of a flood causes the most concern whether or not the elevations are during an ice jam or free flow. Elevation frequencies for areas subject to ice-jam flooding can be based on the development of elevation-frequency relationships for two different populations (ice-jam flood elevations and free-flow flood elevations when adequate data are available). These relations can be combined into a single composite curve for flood elevation at a site under study. Because a combined frequency is needed, separating the annual maximum water-surface elevations into values for ice-jam and free-flow conditions, developing separate elevation frequencies, and then combining the two frequencies is not warranted. Therefore, a single elevation-frequency curve was developed by assigning Weibull plotting positions to both ice-jam and free-flow elevations and fitting a curve to these points on log-normal probability paper.

All of the annual maximum water-surface elevations (table 1) for the streamflow station Little Missouri River at Medora (06336000) were used to develop an elevation-frequency curve (fig. 19) for that site. Only the annual maximum water-surface elevations prior to October 1959 (table 2) for the streamflow station Little Missouri River near Watford City (06337000) were used to develop a curve (fig. 19) for that site. The Weibull plotting position was used to plot the elevations and the graphical method was used to fit a curve to the points. Caution must be exercised when comparing the elevations from the elevation-frequency curve to elevations associated with the flood discharges (figs. 6 and 10) because: (1) The graphical method requires no assumptions as to the type or characteristics of the distribution, and (2) only 20 years of elevation record were used to compute the elevation- frequency curve compared to 48 years of discharge record used to compute the discharge-frequency curve for the streamflow station Little Missouri River near Watford City (06337000). Because ice jams normally are location oriented, these ice-jam analyses apply to the specific location of the streamflow stations.

FLOOD-HAZARD ASSESSMENT

Flooding from the Little Missouri River and the three creeks causes a hazard to persons and property. The flood hazard of the Little Missouri River alone is very different from that of the three creeks. The Little Missouri River has a relatively large drainage basin and the threat of a flood may be known days in advance. The velocity of flood flows in the flood plain is con siderably less than that in the main channel. In contrast, flooding from the three creeks most likely will be caused by intense, localized thunderstorms, and the threat of a flood may be known only hours in advance. The flood water will fill the flood plain of the creek and will flow at fast velocities. Once the flood water of a creek reaches the flood plain of the Little Missouri River, the water will spread out, reducing the velocities and depths.

33

2290

2280-

LITTLE MISSOURI RIVER AT MEDORA (06336000)

70 60 50 40 30 20 10 5 21 0.5 0.2 0.1

EXCEEDANCE PROBABILITY, IN PERCENT

EXPLANATION

FREQUENCY CURVE

1980

1970

O

I-

LJ _J UJ LJJ O

2 1960 CC

COCC 1950LJJI-

1940

OBSERVED ANNUAL PEAKS

193C

LITTLE MISSOURI RIVERNEAR WATFORD CITY

(06337000)

70 60 50 40 30 20 10 5 21 0.5 0.2 0.1

EXCEEDANCE PROBABILITY, IN PERCENT

Figure 19. Water-surface elevation-frequency curves.

34

SUMMARY

Flood analyses were performed on selected reaches along the Little Missouri River and its tributaries (Knutson, Paddock, and Squaw Creeks). Streamflow records were used in the flood flow frequency analysis for the Little Missouri River. The 100-year flood discharge determined for the Little Missouri River South Unit reach was 65,300 ft^/s; the discharge determined for the Little Missouri River Elkhorn Ranch Site reach was 69,000 ft^/s; and the discharge determined for the Little Missouri River North Unit reach was 78,800 ft^/s. A multiple-regression equation based on drainage area and infiltration index was used in the flood flow frequency analysis for the creeks. The 100-year flood discharge determined for Knutson Creek reach was 31,800 ft^/s; the discharge determined for Paddock Creek reach was 18,500 ft^/s; and the discharge determined for Squaw Creek reach was 24,600 ft^/s. Cross-sectional data were obtained by field surveys. Water-surface elevations were computed using step-backwater methods.

Streamflow records for two stations on the Little Missouri River were used to develop maximum observed backwater envelope curves and elevation frequency curves. The maximum observed backwater envelope curves show a trend in which the backwater decreases as the discharge increases. The backwater due to ice approaches zero before reaching the computed elevations for the 100-year discharges.

35

REFERENCES

Barnes, H. H., Jr., 1967, Roughness characteristics of natural channels: U.S. Geological Survey Water-supply Paper 1849, 213 p.

Bluemle, J. P., 1977, The face of North Dakota, the geologic story: North Dakota Geological Survey Educational Series 11, 73 p.

Federal Emergency Management Agency, 1982, Guidelines and specifications for study contractors: Washington, D.C., 132 p.

Shearman, J. O., 1976, Computer applications for step-backwater and floodway analyses: U.S. Geological Survey Open-File Report 76-499, 103 p.

U.S. Geological Survey, 1982, Guidelines for determining flood flow frequency: Interagency Advisory Committee on Water Data, Office of Water Data Coordination, 28 p.

36

FLOOD ANALYSIS ALONG THE LITTLE MISSOURI RIVER WITHIN … · 2010-12-22 · FLOOD ANALYSIS ALONG THE LITTLE MISSOURI RIVER WITHIN AND ADJACENT TO THEODORE ROOSEVELT NATIONAL PARK,

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