U.S. Department of the Interior

Bureau of Reclamation

Technical Service Center

Denver, Colorado March 2010

Technical Report No. SRH-2010-3 

Tom Steed Reservoir -

Mountain Park Dam

2009 Survey
ACKNOWLEDGMENTS

The Bureau of Reclamation's (Reclamation) Sedimentation and River Hydraulics 

(Sedimentation) Group of the Technical Service Center (TSC) prepared and published 

this report. Ben Claggett, Lou Hall, and Ashley Ladd of the Reclamation’s Oklahoma 

Area Office of the Great Plains Region and Ronald Ferrari of the Sedimentation Group 

conducted the bathymetry survey of the reservoir in May and June of 2009. Ron Ferrari 

completed the data processing to generate the new topographic map and area-capacity 

tables presented in this report. Kent Collins of the Sedimentation Group performed the 

technical peer review of this documentation.

Mission Statements

The mission of the Department of the Interior is to protect and 

provide access to our Nation’s natural and cultural heritage and 

honor our trust responsibilities to Indian Tribes and our 

commitments to island communities.

The mission of the Bureau of Reclamation is to manage, develop, 

and protect water and related resources in an environmentally and 

economically sound manner in the interest of the American public.

Reclamation Report

This report was produced by the Bureau of Reclamation’s Sedimentation and 

River Hydraulics Group (Mail Code 86-68240), PO Box 25007, Denver, 

Colorado 80225-0007, www.usbr.gov/pmts/sediment/.

Disclaimer

No warranty is expressed or implied regarding the usefulness or completeness of 

the information contained in this report. References to commercial products do 

not imply endorsement by the Bureau of Reclamation and may not be used for 

advertising or promotional purposes.
U.S. Department of the Interior

Bureau of Reclamation

Technical Service Center

Water and Environmental Resources Division

Sedimentation and River Hydraulics Group

Denver, Colorado March 2010

Technical Report No. SRH-2010-3

Tom Steed Reservoir -

Mountain Park Dam

2009 Survey

prepared by

Ronald L. Ferrari 
REPORT DOCUMENTATION PAGE Form Approved 

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1. REPORT DATE (DD-MM-YYYY) 

March 2010

2. REPORT TYPE 3. DATES COVERED (From – To)

4. TITLE AND SUBTITLE 

Tom Steed Reservoir –

Mountain Park Dam

2009 Survey

5a. CONTRACT NUMBER

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S) 

Ronald L. Ferrari

5d. PROJECT NUMBER

5e. TASK NUMBER

5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 

Bureau of Reclamation, Technical Service Center, Denver, CO 80225

8. PERFORMING ORGANIZATION REPORT 

NUMBER 

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 

Bureau of Reclamation, Denver Federal Center, PO Box 25007

Denver, CO 80225-0007

10. SPONSOR/MONITOR'S ACRONYM(S)

11. SPONSOR/MONITOR'S REPORT 

NUMBER(S) 

12. DISTRIBUTION/AVAILABILITY STATEMENT 

13. SUPPLEMENTARY NOTES 

14. ABSTRACT

Reclamation surveyed Tom Steed Reservoir (impounded by Mountain Park Dam) in late May through early June 2009 to 

develop updated reservoir topography and compute present storage-elevation relationships (area-capacity tables). The 

underwater survey, conducted between water surface elevations 1,408.2 and 1,408.4 (feet) used sonic depth recording equipment 

interfaced with a real-time kinematic (RTK) global positioning system (GPS) that provided continuous sounding positions 

throughout the underwater portion of the reservoir covered by the survey vessel. The above-water topography was obtained by 

digitizing the reservoir’s water edge from several years of aerial photographs collected by the United States Department of

Agriculture (USDA). Four years of flights that ranged in reservoir water surface elevations between 1,403.3 through 1,412.2

feet were used. These digitized images enabled contours to be developed where boat access was not possible due to vegetation

and shallow water conditions. This study assumed no change since the original survey at elevation 1,412.0 and above. Accurate

mapping of the upper reservoir contours would require aerial collection during low reservoir conditions from which detailed 

reservoir contours could be developed.

As of June 2009, at conservation reservoir pool elevation 1,411.0, the surface area was 6,362 acres with a total capacity of

97,322 acre-feet. Since the June 1975 closure of Tom Steed Dam this survey only measured a slight total capacity change below

elevation 1,411.0. The minimal measured change was due to accuracy differences between the original and 2009 data sets. This 

survey measured a minimum elevation of 1,372.6 or 8.6 feet of sediment accumulation near the dam.

15. SUBJECT TERMS 

reservoir area and capacity/ sedimentation/ reservoir surveys/ global positioning system/ sounders/ contour 

area/ RTK GPS

16. SECURITY CLASSIFICATION OF: 17. LIMITATION 

OF ABSTRACT

18. NUMBER 

OF PAGES 

19a. NAME OF RESPONSIBLE PERSON

a. REPORT b. ABSTRACT a. THIS PAGE 19b. TELEPHONE NUMBER (Include area code)

Standard Form 298 (Rev. 8/98) 

Prescribed by ANSI Std. Z39.18 

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Table of Contents

Page

Introduction ...................................................................................................................................... 1

Summary and Conclusions............................................................................................................... 4

Control Survey Data Information..................................................................................................... 6

Reservoir Operations........................................................................................................................ 7

Hydrographic Survey Equipment and Method ................................................................................. 8

Reservoir Area and Capacity.......................................................................................................... 13

Topography Development....................................................................................................... 13

Development of the 2009 Tom Steed Reservoir Surface Areas.............................................. 16

2009 Storage Capacity ............................................................................................................ 25

2009 Reservoir Analyses................................................................................................................ 27

References...................................................................................................................................... 28

Index of Figures

Page

Figure 1 - Reclamation Reservoirs Located in Oklahoma................................................................ 1

Figure 2 – Mountain Park Project and surrounding features. ........................................................... 2

Figure 3 - Mountain Park Dam and operating spillway. .................................................................. 3

Figure 4 - USGS Quad of Tom Steed Reservoir. The red outlined, blue shaded area is reservoir 

elevation 1,411. The red outline of the west reservoir area is elevation 4,110. ..................... 4

Figure 5 – View of the reservoir from the East Dike. ...................................................................... 6

Figure 6 - Survey Vessel with Mounted Instrumentation on Jackson Lake in Wyoming. ............... 8

Figure 7 - Tom Steed Reservoir 2009 survey data points. ............................................................. 11

Figure 8 - Tom Steed Reservoir at East Dike. ................................................................................ 14

Figure 9 - Mountain Park Reservoir, West Dike. ........................................................................... 14

Figure 10 - Tom Steed Reservoir, Otter Creek............................................................................... 15

Figure 11 - Tom Steed Reservoir topographic map........................................................................ 17

Figure 12 - Tom Steed Reservoir topographic map image............................................................. 18

Figure 13 - Tom Steed Reservoir topography. ............................................................................... 19

Figure 14 – Tom Steed Reservoir Area and Capacity Plots........................................................... 23

Index of Tables

Page

Table 1 - Reservoir Sediment Data Summary (page 1 of 2)........................................................... 21

Table 2 - Tom Steed Reservoir survey results................................................................................ 26
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1

Tom Steed Reservoir -

Mountain Park Dam 2009 Survey

Introduction

Mountain Park Dam impounds Tom Steed Reservoir. Both are principal features 

of the Mountain Park Project in Kiowa County located in southwestern Oklahoma

(Figure 1). The dam, on West Otter Creek, is about 4 miles north of Snyder, 3 

miles northwest of Mountain Park, and 20 miles northeast of Altus, Oklahoma. 

The project includes the Bretch Diversion Dam and Canal located on Elk Creek 

about five miles south of Hobart (Figure 2). Bretch Diversion Dam can divert up 

to 1,000 ft3/s from Elk Creek into Otter Creek which provides water supplements 

into Tom Steed Reservoir.

Two saddles with embankment dikes are located east and west of Mountain Park 

Dam to help impound Tom Steed Reservoir. The East Dike is 1.2 miles east of 

the left dam abutment and the West Dike is 1.4 miles west of the right abutment. 

The East Dike length is 10,630 feet with a structural height of 28 feet and the 

West Dike length is 13,233 feet with a structural height of 20 feet. The crests for 

both dikes are near elevation 1,428 feet.1

Figure 1 - Reclamation Reservoirs Located in Oklahoma.

 

1

Elevations in feet. Elevations based on original project datum established by Reclamation that is near 

National Geodetic Vertical Datum of 1929 (NGVD29) and approximately 0.5 feet lower than the North 

American Vertical Datum of 1988 (NAVD88).
2

Figure 2 – Mountain Park Project and surrounding features.

Mountain Park Dam is a double curvature thin arch concrete dam built from 1973 

through 1975 (Figure 3). The thrust block crests are at elevation 1,423.6 with the 

parapet wall crest at elevation 1,427.0. The dam’s dimensions are:

Hydraulic height2 59 feet Dam crest elevation 1,423.6

Structural height 133 feet Parapet crest elevation 1,427.0

Crest length 535 feet 

 

2

The definition of such terms as “hydraulic height,” “structural height,” etc. may be found in manuals such 

as Reclamation’s Design of Small Dams and Guide for Preparation of Standing Operating Procedures for 

Dams and Reservoirs, or ASCE’s Nomenclature for Hydraulics.
3

Figure 3 - Mountain Park Dam and operating spillway.

An uncontrolled overflow spillway spans 320 feet of the axis of the dam with 

crest elevation 1,414.0 at top of the exclusive flood control pool. The spillway is 

designed for maximum discharge 38,300 ft3/s at maximum reservoir elevation 

1,423.6. The outlet works consists of an intake structure near the left abutment 

and three outlets for river, flood, and municipal water releases.

The Mountain Park Project is operated and maintained to provide water storage 

for municipal and industrial uses as well as flood control. The project also 

provides recreation and fish and wildlife conservation benefits. The dam, 

reservoir, and distribution system are operated by the Mountain Park Master 

Conservancy District.

The drainage area above the dam is 121 square miles and is generally flat. The 

upper portion of the basin is crop and pasture land. The lower portion consists 

primarily of a narrow and steep-sided valley cut through granite bedrock. The 

reservoir is around 4.5 miles long with an average width of 2.2 miles (Figure 4).
4

Figure 4 - USGS Quad of Tom Steed Reservoir. The red outlined, blue shaded area is 

reservoir elevation 1,411. The red outline of the west reservoir area is elevation 4,110.

Summary and Conclusions

This Reclamation report presents the results of the 2009 survey of Tom Steed

Reservoir. The primary objectives of the survey were to gather data needed to:

$ develop reservoir topography

$ compute current area-capacity relationships

$ estimate storage depletion, by sediment deposition, since dam closure

A control survey was conducted using the on-line positioning user service 

(OPUS) and RTK GPS to establish a horizontal and vertical control network near 

the reservoir for the hydrographic survey. OPUS is operated by the National 

Geodetic Survey (NGS) and allows users to submit GPS data files for processing 

with known point data to determine positions relative to the national control 

network. The GPS base was set over a temporary mark on the East Dike. The

coordinates for this point were processed using OPUS, and from this base 

additional points were measured during the May and June 2009 hydrographic 

survey.
5

The horizontal control for this study was in feet, Oklahoma South state plane 

coordinates, in the North American Datum of 1983 (NAD83). The vertical 

control was in feet, tied to NAVD88 and the Reclamation project vertical datum. 

All elevations in this report are referenced to Reclamation’s project or 

construction vertical datum that is near NGVD29 and about 0.5 feet lower than 

NAVD88.

The bathymetric survey was conducted using sonic depth recording equipment 

interfaced with a differential global positioning system capable of determining 

sounding locations within the reservoir. The system continuously recorded depth 

and horizontal coordinates of the survey boat as it navigated along predetermine 

grid lines. The positioning system provided information that allowed the boat 

operator to maintain a course along these grid lines. Water surface elevations 

recorded by a Reclamation gage during the time of collection were used to 

convert the sonic depth measurements to reservoir bottom elevations tied to the 

project’s vertical datum.

The initial above-water topography for the 2009 survey was determined by 

digitizing contour lines from the USGS quads of the reservoir area. Orthographic 

aerial images collected between 2004 and 2008 and between water surface 

elevations 1,403.3 and 1,412.2 were downloaded from the USDA data web site 

(USDA, 2010) for this analysis. Reservoir contours were developed at various

water surface elevations by digitizing the water surface edge from the aerial 

images. The aerial images were collected at high altitudes over the reservoir,

making it difficult at times to distinguish the reservoir water surface edge. 

However, it was determined that the developed contours were the best means to 

accurately locate the present shoreline. The original surface areas for portions of 

the original reservoir capacity computations were measured from the USGS quad 

contours at 10-foot intervals. The recent aerial flights provided more accurate 

detail of the reservoir between elevation 1,403.3 and 1,412.2. This study assumed 

no change since the original measured and computed surface areas from elevation 

1,412.0 and above.

The new 2009 Tom Steed Reservoir topographic map is a combination of the 

digitized water surface edges from the USDA orthographic aerial photographs and 

the 2009 underwater survey data points. A topographic computer program 

generated the 2009 reservoir surface areas at predetermined contour intervals 

from the combined reservoir data. The 2009 area and capacity tables were 

produced by a computer program that used the measured contour surface areas 

and a curve-fitting technique to compute the area and capacity values at 

prescribed elevation increments (Bureau of Reclamation, 1985).

Tables 1 and 2 contain summaries of Tom Steed Reservoir and watershed 

characteristics for the 2009 study. The 2009 survey determined the reservoir has 

a total storage capacity of 97,322 acre-feet with a surface area of 6,362 acres at
6

top of the conservation pool, elevation 1,411.0. Since June 1975 Mountain Park 

Dam closure, this survey only measured a slight change in reservoir capacity from 

the original reservoir volume computations at elevation 1,411.0. The 2009 survey 

measured 4,258 acre-feet of lost capacity below elevation 1,388.0, but the 

capacity was essentially regained between elevation 1,388.0 and 1,412.0. The 

losses and gains were computed by comparing the original surface areas and the 

2009 surface areas for the reservoir. It is assumed that a small portion of the loss 

from elevation 1,388.0 and below was due to material from the upper elevation 

shoreline being eroded over time and settling in the lower elevations of the 

reservoir. However, it is believed the computed capacity losses and gains are 

primarily due to accuracy differences between the original and 2009 measured 

surface areas. The 2009 survey measured a minimum elevation of 1,372.6 or 

around 8.6 feet of sediment accumulation at the dam.

Control Survey Data Information

Prior to the 2009 survey, a temporary point was set on the East Dike using OPUS

to establish the horizontal and vertical control datum (Figure 5). OPUS, operated 

by the NGS, allows users to submit GPS data files that are processed with known 

data to determine point positions relative to the national control network. The

East Dike temporary point was the base for the entire reservoir survey.

Figure 5 – View of the reservoir from the East Dike.

The horizontal control was in Oklahoma south zone state plane coordinates in 

NAD83 and vertical control tied to the Reclamation project datum. All elevations 
7

in this report are referenced to Reclamation’s project or construction vertical 

datum that is near NGVD29 and approximately 0.5 feet lower than NAVD88.

Topographic survey shots were taken of the water surface and compared to the 

water surface gage readings. The RTK GPS elevations in NAVD88 averaged

0.45 feet higher than the recorded gage reading which is near the 0.5 foot shift 

between NGVD29 and NAVD88. Survey shots were also taken on top of the East 

Dike alignment and varied from elevation 1,427.7 to 1,428.2 compared to design 

crest elevation 1,428.

A topographic shot was also collected on a BOR brass cap, labeled 1,409.889, 

located downstream of the East Dike (coordinates for the 2009 topographic shot 

listed below). The measurement was 0.39 feet higher than the stamped elevation 

on the brass cap. As of this report, no history was located on how the elevation 

on this brass cap was originally established.

North 518,729.484

East 1,679,651.533

Elevation 1,410.75 (NAVD88)

Elevation 1,410.28 (NGVD29) (computed using US Army Corp of 

Engineers’ program CORPSCON)

Reservoir Operations

Tom Steed Reservoir is part of the Mountain Park Project that was designed to 

provide storage for municipal, industrial, and flood control. The project also 

provides recreation facilities along with fish and wildlife conservation. The June

2009 capacity table computed 197,347 acre-feet of total storage below the 

maximum water surface elevation 1,423.6 (Table 1). The 2009 survey measured a 

minimum lake bottom elevation of 1,372.6. The following values are from the 

June 2009 capacity table:

$ 79,741 acre-feet of surcharge storage, elevation 1,414.0 through 

1,423.6.

$ 20,284 acre-feet of flood control storage, elevation 1,411.0 through

1,414.0. 

$ 92,922 acre-feet of conservation pool storage, elevation 1,386.3 through

1,411.0. 

$ 4,383 acre-feet of inactive pool storage, elevation 1,376.5 through 

1,386.3.

$ 17 acre-feet of dead pool storage below elevation 1,376.5.
8

The computed annual inflow and reservoir stage records for Tom Steed Reservoir

are listed by water year in Table 1 for the period 1975 through 2009. The inflow 

values were computed by Reclamation’s Oklahoma Area Office for this study and 

are rough estimates of reservoir inflows by measured monthly change in reservoir 

elevations resulting in computed capacity change and adjusted for estimated

monthly reservoir evaporation rates. These inflow values show the annual 

fluctuation with a computed average annual inflow of 35,260 acre-feet. The 

maximum end of month reservoir elevation of 1,414.5 was recorded during water 

year 1987. After initial filling in 1980, a minimum end of month reservoir

elevation of 1,399.8 was recorded during water years 1993 and 1998.

Hydrographic Survey Equipment and

Method

The hydrographic survey equipment was mounted in the cabin of a 24-foot trihull 

aluminum vessel equipped with twin in-board motors (Figure 6). The 

hydrographic system included a GPS receiver with a built-in radio, a depth 

sounder, a helmsman display for navigation, a computer, and hydrographic 

system software for collecting the underwater data. An on-board generator 

supplied power to all the equipment. The shore equipment included a second 

GPS receiver with an external radio. The GPS receiver and antenna were 

mounted on a survey tripod over a known datum point and a 12-volt battery 

provided the power for the shore unit.

Figure 6 - Survey Vessel with Mounted Instrumentation on Jackson Lake in Wyoming.

The Sedimentation and River Hydraulics Group uses RTK GPS with the major 

benefit being precise heights measured in real time to monitor water surface 

elevation changes. The basic output from a RTK receiver are precise 3-D 

coordinates in latitude, longitude, and height with accuracies on the order of 2 
9

centimeters horizontally and 3 centimeters vertically. The output is on the GPS 

datum of WGS-84 that the hydrographic collection software converted into

Oklahoma’s state plane coordinates, south zone in NAD83. The RTK GPS 

system employs two receivers that track the same satellites simultaneously just 

like with differential GPS.

The Tom Steed Reservoir bathymetric survey was conducted in 2009 from May 

19-21 and June 1-4 between water surface elevation 1,408.2 and 1,408.4

(Reclamation project datum). The bathymetric survey was conducted using sonic 

depth recording equipment, interfaced with a RTK GPS, capable of determining 

sounding locations within the reservoir. The survey system software continuously 

recorded reservoir depths and horizontal coordinates as the survey boat moved 

along closely spaced grid lines covering the reservoir area. Most transects (grid 

lines) were run somewhat parallel to the upstream-downstream alignment of the 

reservoir at around 300-foot spacing. The survey vessel's guidance system gave 

directions to the boat operator to assist in maintaining the course along these 

predetermined lines. Data was collected along the shore by the survey vessel for 

the majority of the reservoir. During each run, the depth and position data were 

recorded on the laptop computer hard drive for subsequent processing. Final 

processing of the underwater collected data set resulted in approximately 139,000 

points (Figure 7).

The 2009 underwater data was collected by a depth sounder calibrated by 

lowering an instrument that measured the average sound velocity of the reservoir 

water column. The sounder was further checked by lowering a weighted marked 

cable to compare the digital depth versus the cable depth. The weighted cable 

was lowered near the dam and also in the main body of the reservoir at different 

depths. Near the dam the sediment laden bottom was very soft allowing the 

weight to easily sink about 1 foot below the reservoir bottom. In the main part of 

the reservoir the bottom was much more solid. The collected depth data were 

digitally transmitted to the computer collection system through a RS-232 port. 

The depth sounder also produced an analog hard-copy chart of the measured 

depths. These graphed analog charts were analyzed during post-processing, and 

when the analog charted depths indicated a difference from the computer recorded 

bottom depths, the computer data files were modified. The water surface 

elevations at the dam, recorded by a Reclamation gage, were used to convert the 

sonic depth measurements to true lake-bottom elevations. Additional information 

on collection and analysis procedures is included in Engineer and Design: 

Hydrographic Surveying (Corps of Engineers, January 2002) and Reservoir 

Survey and Data Analysis (Ferrari and Collins, 2006).
10

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11

Figure 7 - Tom Steed Reservoir 2009 survey data points.
12

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13

Reservoir Area and Capacity

Topography Development

The topography of Tom Steed Reservoir was developed from combined 2009 

bathymetric data and the digitized reservoir water surface edge from several sets 

of aerial photographs collected by the USDA. The reservoir water surface 

elevation was recorded by the Reclamation gage on the day of each aerial flight:

Year Water Surface Elevation

2004 1,403.3

2005 1,406.7

2006 1,404.6

2008 1,412.0 (average of two flight lines)

Contours digitized from USGS quads at elevations 1,410 and 1,411 were used 

during field collection and to evaluate the USDA aerial images of the reservoir. 

As part of the analysis, the 1,411 USGS contour was used as a hardclip polygon 

for the 2009 collected data. The resulting computation values were similar to 

those using the contours developed from USDA aerials only. Since the digitized 

contours from the USDA aerial photographs provided more detail and more 

current upper elevation contours, the USGS quad contours were not used in the 

development of the final 2009 Tom Steed Reservoir topography for this study.

Following are images that compare the digitized contours from the USGS and 

USDA data sets. Footnotes on the original area capacity tables for Tom Steed 

reservoir indicate that some of the surface areas were developed by digitizing the 

USGS quad contours that for this area are only at 10-foot intervals. As seen on 

Figure 8, the reservoir area outlined from the digitized USGS contour elevation 

1,411 (outlined by the blue shaded area on Figure 4) lines up well with the USDA

developed contours. This was the case for the majority of the reservoir. Figures 9 

and 10 illustrate areas of the reservoir where the USDA developed contours 

plotted outside the USGS 1,411 digitized contour. This explains why the original 

total surface areas in the upper elevations are less than the total surface areas 

developed by the 2009 survey. The larger surface areas measured for the 2009 

survey resulted in the 2009 total reservoir capacity at elevation 1,411.0 being near 

the original capacity computation even though sediment deposition reduced the 

capacity in the lower elevation zone of the reservoir. During the 2009 field 

survey, shoreline erosion was observed, but the majority of the measured change 

in the upper elevation is likely due to the increased detail of the upper contours

developed from the USDA aerial images compared to those developed from the 

USGS quads. The aerial images represent actual reservoir conditions at given 

elevations.
14

Figure 8 - Tom Steed Reservoir at East Dike.

Figure 9 - Mountain Park Reservoir, West Dike.
15

Figure 10 - Tom Steed Reservoir, Otter Creek.

A developed contour just outside the 2008 aerial digitized contour, elevation 

1,411.9, was used as a hard boundary for the 2009 developed contours. This clip 

was assigned elevation 1,413.0 and was used during the triangular irregular 

network (TIN) and contour development to prevent interpolation outside the 

enclosed polygon or reservoir area.

Contours for the reservoir from elevation 1,412.0 and below were developed from

the TIN generated within ARCGIS. A TIN is a set of adjacent non-overlapping 

triangles computed from irregularly spaced points with x,y coordinates and z 

values. A TIN is designed to deal with continuous data such as elevations. The 

TIN software uses a method known as Delaunay's criteria for triangulation where 

triangles are formed among all data points within the polygon clip. The method 

requires that a circle drawn through the three nodes of a triangle will contain no 

other point, meaning that all the data points are connected to their nearest 

neighbors to form triangles and all the collected data points are preserved. The 

TIN method is discussed in detail in the ARCGIS user’s documentation, (ESRI, 

2010).

The linear interpolation option of the ARCGIS TIN and CONTOUR commands

was used to interpolate contours from the Tom Steed Reservoir TIN. The areas of 

the enclosed contour polygons at one-foot increments were computed from the 

survey data for elevations 1,473.0 through 1,410.0. Since limited above water 
16

data was collected, this study assumed no change in reservoir surface area since 

the 1975 survey at elevation 1,412.0 and higher. The surface area of the contour 

digitized from USDA aerial photography near elevation 1,412 was very similar to 

the original computed surface area for that elevation. The reservoir contour 

topography at 2-foot intervals from elevation 1,412.0 and below is presented on

Figures 11 through 13. Development of the contours within ARCGIS was 

directly from the TIN using all the enclosed data points resulted in a somewhat 

jagged representation of the contours. There are other mapping packages that can 

be used to generate smoother contours, but for this study the TIN approach 

includes all data points to produce the most accurate surface area and resulting 

volume. The best means to develop the upper contours and resulting above water 

reservoir areas would be by conducting a detailed aerial survey with the reservoir 

drawn down.

Development of the 2009 Tom Steed Reservoir Surface 

Areas

The 2009 surface areas for Tom Steed Reservoir were computed at 1-foot 

increments directly from the reservoir TIN from elevation 1,374.0 through 

1,410.0. The TIN was developed from the 2009 collected data and digitized data 

sets within the hardclip polygon created from the previously described digitized 

1,413.0 contour. Surface area calculations were performed using ARCGIS

commands that compute areas at user-specified elevations directly from the TIN. 

For the purpose of this study, the measured survey areas at 2-foot increments from 

elevation 1,374.0 through 1,410.0 were used in computing the new area and 

capacity tables. This study assumed no change in surface area, since the original 

or 1975 survey, at elevation 1,412.0 and above.

Table 1 provides a summary of the 2009 survey conducted on Tom Steed 

Reservoir. The area and capacity curves for the original and 2009 surveys are 

plotted on Figure 14.
17

Figure 11 - Tom Steed Reservoir topographic map.
18

Figure 12 - Tom Steed Reservoir topographic map image.
19

Figure 13 - Tom Steed Reservoir topography.
20

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21

1 . 2 . West Otter Creek 3 . STATE: Oklahoma

4 . 5 . Mountain Park 6 . COUNTY:Kiowa

7 . ° 4 4 ' 1 9 " ° 5 9 ' 1 5 " 8 . 19 . SP ILLWAY CREST EL. 2

10. 11. 12. GROSS STORAGE 15.

CAPACITY, AC-FT

a. 3

b.

c.

d. 16.

e.

f .

g.

17. LENGTH OF RESERVOIR 4

18. 522. 6INCHES

19. NET SEDIMENT CONTRIBUTING AREA 523. MEAN ANNUAL RUNOFF 7INCHES

20. LENGTH MILES AVG. WIDTH MILES 24. MEAN ANNUAL RUNOFF 7 ACRE-FEET

21. 25. °F °F6

26. DATE OF 27. 28. 29. 30. 31.

26. DATE OF 35. 36.

7

26. DATE OF 37. 38.

26. DATE OF 39.AVG. DRY WT. 40. SED. DEP. TONS/MI.2-YR 41. STORAGE LOSS, PCT. 42.SEDIMENT 

(#/FT3) b. TOTAL b. TOTAL TO INFLOW, PPM

TO DATE DATE a. PER. b. TOT.

43.

RESERVOIR SEDIMENT

DATA SUMMARY

Tom Steed

1,801

1,386.3

1,376.5

1,268

DATA SHEET NO.

DATE

STORAGE

1,423.0

14.

BEGAN

DATE NORMAL

6/1975

88,804 OPERATIONS

6,749

6/1975

NAME OF RESERVOIR 1

DATE

OF

SURVEY

DATE

OF

SURVEY

1,414.0

ACRE-FEET

t o 120

330

MILES AVG. WIDTH OF RESERVOIR

MIN. ELEVATION 560 -11

SURVEY

26. 44.

1 0

10-

26.

CAPACITY

WATER INFLOW TO DATE, AF

SURVEY

PERIOD CAPACITY LOSS, ACRE-FEET

TOTAL

PERIOD

U

A

T

Y

SURVEY

V

S

6/2009

MAX. ELEVATION 14,000 ANNUAL TEMP, MEAN °F RANGE

a. TOTAL b.

I

N

AREA, AC. ACRE - FEET

NO. OF

a. MEAN ANN.

34.0 Contour (D)

ANNUAL

PRECIPITATION

SURVEY

6/2009 9

97,354

2.76

V

O

I

R

B

A

6,330

MEAN ANNUAL PRECIPITATION

SQUARE MILES

SQUARE MILES

8,550

1,801

97,354

TOTAL DRAINAGE AREA

2.2 MILES

Bureau of Reclamation

17W

SURFACE AREA, ACRES

3 4

OWNER:

SEC

LAT

1 6

M

STREAM:

NEAREST P.O.

D

A TWP. 3 N RANGE

TOP OF DAM ELEVATION:

ORIGINAL 13. ORIGINAL 

LONG 9 8

RATIO AF/AF

35,260 114,295

33.

MEAN ANN. b. TOTAL

35,260

9

2-ft

C/I

79,741

20,268

BEGAN

RANGES OR 

INTERVALS

SURFACE

26.5

117,622

9,478

7,134

197,363

35,260

5.5

TYPE OF 32.

SURVEY

2.76 8

TOTAL SEDIMENT DEPOSITS TO DATE, AF

PERIOD WATER INFLOW, ACRE-FEET

c. TOTAL

6,330 8

97,322

 /MI.2-YR.

a.

6/2009

PERCENT OF TOTAL SEDIMENT LOCATED WITHIN REACH DESIGNATION

9 0

70-

8 0

DEPTH DESIGNATION RANGE BY RESERVOIR ELEVATION

2 0 3 0 4 0 6 0 7 0

50-

REACH DESIGNATION PERCENT OF TOTAL ORIGINAL LENGTH OF RESERVOIR

PERCENT OF TOTAL SEDIMENT LOCATED WITHIN DEPTH DESIGNATION

100

105-

DEAD

TOP OF POOL

FLOOD CONTROL

POWER

1,423.6

1,414.0

4.5

YRS YRS

5-ft

SURCHARGE

INACTIVE

STORAGE

ALLOCATION

1,411.0

JOINT USE

CONSERVATION

ELEVATION

121

Contour (D)

121

6/1975

D

PERIOD

R

E

S

E

S

R

1 0

PER.

34.

R

34.0

PER.

E

A 6/2009

125

115-

105 111 115 120

0 - 20- 30- 60- 80- 90- 100- 110- 120-

 

AVG. ANN. c.

1 0

 /MI.2-YR.

a. 

11,989,800

AVG. ANN. a.

1 0

c. b.

6,362

11,989,800

a. AVG. ANNUAL

b. MAX. ANN.

Table 1 – Reservoir Sediment Data Summary (page 1 of 2).
22 9

1

2

3

4

5

6

7

8

9

10

11 End of month maximum and minimum elevations. 

 survey results is not possible. 

1,423.6 9,478 197,347

1,418.0

47. REMARKS AND REFERENCES

132,363

8,111 148,097 1,420.0 8,599 164,807

117,606 1,416.0 7,623

1,422.0 9,088 182,494

1,411.0

1,412.0 6,646 103,826 1,414.0 7,134

91,101

1,380.0

1,402.6

1,402.0 4,532 47,898 1,404.0 1,406.0 5,441

24,936 31,696

7,491

67,937

1,408.0 5,801 1,410.0 6,362 97,322

1,386.0

1,396.0

1,390.0

1,129

3,157

DATE

Reservoir length at elevation 1,411.

Total drainage area from Reclamation's SOP report. Reservoir water supplements from Bretch Diversion Dam, drainage area of 549 mi 2.

49. Bureau of Reclamation March 2010

2009 capacities computed by Reclamation's ACAP program. Assume no surface area change from original values from el. 1412.0 and above.

Due to detail difference between original and 2009 surveys, computing capacity loss due to sediment deposition by comparing 

48. AGENCY MAKING SURVEY Bureau of Reclamation

AGENCY SUPPLYING DATA

Elevations in feet based on original project datum reported as NGVD29; around 0.5 feet lower than NAVD88. Parapet wall crest, el. 1,427.0.

Concrete arch portion of dam functions as uncontrolled overflow spillway with crest elevation 1,414.0.

 from Bretch Diversion Dam. 

Elevations from Reservoir Capacity Allocation in SOP, dated 1/2000. Capacity values recomputed for 2009 analysis using ACAP.

Mean annual runoff from 1975 through May 2009 from Reclamation's Regional computed inflows. Rough estimate. Supplemental water 

Surface area and capacity at elevation 1,411.0, conservation capacity.

Bureau of Reclamation Project Data Book, 1981. Values for Mountain Park Project.

0

61,760

1,407.6

1,414.3

2005

2007

1,403.8

7, 11

1,376.0

YEAR MAX. ELEV. MIN. ELEV. INFLOW, AF YEAR MAX. ELEV. MIN. ELEV. INFLOW, AF

79,222

1,406.9

1

46. ELEVATION - AREA - CAPACITY - DATA FOR

2009

12,930

1,401.5

1978 1,399.9 35,979 1979 1,409.0 1,404.3 31,690

1,414.5 1,410.0 114,295

1,412.1

1986 1,410.9

1980 1,412.8

65,775 1991 1,411.2 1,407.6 37,765

1981

1,407.2 41,248 1987

1,406.4

12,100

42,125

1988

1990 1,411.0 1,408.4

1,390.7

1,407.9 1,405.8 18,878

1984 1,406.8 45,319 1985 1,407.9 1,406.1 30,332

1975

38,900

8,117

1977 1,402.8 1,392.1

1,409.0 1,406.7

1,399.8 63,881

1,402.2 74,605

1996 1,410.8 1,407.5 31,763 1997 1,412.0 1,408.7 29,089

1992 1,410.9 1,409.1 35,022 1993 1,412.2

1994 1,408.9 1,404.4 8,786 1995 1,411.8

1998 1,411.2 1,399.8 31,974 1,408.1 1,400.4 26,842

2002 1,407.0 1,403.4 8,888

2000 1,408.7 1,405.0 30,846 1,411.1 1,407.1 31,905

24,397

2001

1999

2003

26,739

1,405.4 1,403.3

ELEVATION

SURVEY

AREA CAPACITY

1,372.6 0 1,374.0 1

CAPACITY ELEVATION AREA CAPACITY

1,394.0

12 1,376.5 13 17

1,176 4,400

10 1,378.0

39,341

6,636

19,058

4,040

1,388.0

1,400.0

57,459

6,079

4,054 1,386.3

1,392.0 2,271

1,398.0 3,602

5,020

45. RANGE IN RESERVOIR OPERATION

2004 1,404.0

1,393.1 1,388.9 9,668

1,407.1

1976

2008 1,411.4 1,408.4

2009 CAPACITY

ELEVATION AREA

28

14,078 2,716

1,463

1,854 9,964

145 196 1,382.0 448 802 1,384.0

47

2,085

2009 1,408.4 1,406.6

835

1982 1,411.8 1,406.4 38,776 1983

15,152

1,410.9 1,408.2 46,148 1989 1,411.2 1,409.3 31,974

27,824

2006 1,401.9

Table 1 – Reservoir Sediment Data Summary (page 2 of 2).
23

1,365.0

1,370.0

1,375.0

1,380.0

1,385.0

1,390.0

1,395.0

1,400.0

1,405.0

1,410.0

1,415.0

1,420.0

1,425.0

10,000 9,000 8,000 7,000 6,000 5,000 4,000 3,000 2,000 1,000 0

1,365.0

1,370.0

1,375.0

1,380.0

1,385.0

1,390.0

1,395.0

1,400.0

1,405.0

1,410.0

1,415.0

1,420.0

1,425.0

0 20,000 40,000 60,000 80,000 100,000 120,000 140,000 160,000 180,000 200,000 Elevation (feet)

Capacity (acre-feet)

Area-Capacity Curves for Tom Steed Reservoir

2009 Survey

Original Survey

Area

Capacity

Area (acre)

Capacity (acre-feet)

Figure 14 – Tom Steed Reservoir Area and Capacity Plots
24

This page intentionally left blank.
25

2009 Storage Capacity

The storage-elevation relationships based on the measured surface areas were 

developed using the area-capacity computer program ACAP (Reclamation, 1985). 

The ACAP program computes the area and capacity at elevation increments from 

0.01 to 1.0 foot by linear interpolation between the given contour surface areas. 

The program begins by testing the initial capacity equation over successive 

intervals to ensure that the equation fits within an allowable error limit. The error 

limit was set at 0.000001 for Tom Steed Reservoir. The capacity equation is then 

used over the full range of intervals fitting within the allowable error limit. For 

the first interval at which the initial allowable error limit is exceeded, a new 

capacity equation (integrated from basic area curve over that interval) is utilized 

until it exceeds the error limit. Thus, the capacity curve is defined by a series of 

curves, each fitting a certain region of data. Through differentiation of the 

capacity equations, which are of second order polynomial form, final area 

equations are derived:

y = a1 + a2x + a3x

2

where: y = capacity

x = elevation above a reference base

a1 = intercept

a2 and a3 = coefficients

Results of the Tom Steed Reservoir area and capacity computations are listed in a 

separate set of 2009 area and capacity tables and have been published for the 0.01, 

0.1 and 1-foot elevation increments (Bureau of Reclamation, 2009). A 

description of the computations and coefficients output from the ACAP program 

is included with these tables. The original and 2009 area-capacity relationships 

are listed on Table 2 and the curves are plotted on Figure 14. As of June 2009, at 

conservation use elevation 1,411.0, the surface area was 6, 362 acres with a total 

capacity of 97,322 acre-feet.
26

1 2 3 4 5 6 7 8

2009 2009

Elevations Original Original 2009 2009 Area Volume Percent of

Survey Capacity Survey Survey Difference Difference Reservoir

(feet) (acres) (acre-feet) (acres) (acre-feet) (acres) (acre-feet) Depth

1,423.6 9,478 197,363 9,478 197,347 0 1 6 100.0

1,422.0 9,088 182,510 9,088 182,494 0 1 6 97.3

1,420.0 8,599 164,823 8,599 164,807 0 1 6 94.0

1,418.0 8,111 148,113 8,111 148,097 0 1 6 90.6

1,416.0 7,623 132,379 7,623 132,363 0 1 6 87.2

1,414.0 7,134 117,622 7,134 117,606 0 1 6 83.9

1,412.0 6,646 103,842 6,646 103,826 0 1 6 80.5

1,411.0 6,330 97,354 6,362 97,322 3 2 3 2 78.9

1,410.0 6,015 91,181 6,079 91,101 6 4 8 0 77.2

1,408.0 5,582 79,584 5,801 79,222 219 362 73.8

1,406.0 5,148 68,854 5,441 67,937 293 917 70.5

1,404.0 4,715 58,991 5,020 57,459 305 1532 67.1

1,402.0 4,282 49,994 4,532 47,898 250 2096 63.8

1,400.0 3,849 41,863 4,040 39,341 191 2522 60.4

1,398.0 3,416 34,598 3,602 31,696 186 2902 57.0

1,396.0 2,982 28,200 3,157 24,936 175 3264 53.7

1,394.0 2,549 22,669 2,716 19,058 167 3611 50.3

1,392.0 2,116 18,004 2,271 14,078 155 3926 47.0

1,390.0 1,752 14,136 1,854 9,964 102 4172 43.6

1,388.0 1,490 10,894 1,463 6,636 -27 4258 40.3

1,386.3 1,268 8,550 1,176 4,400 -92 4150 37.4

1,386.0 1,229 8,175 1,129 4,054 -100 4121 36.9

1,384.0 967 5,979 835 2,085 -132 3894 33.6

1,382.0 706 4,306 448 802 -258 3504 30.2

1,380.0 444 3,156 145 196 -299 2960 26.8

1,378.0 379 2,333 2 8 4 7 -351 2286 23.5

1,376.5 330 1,801 1 3 1 7 -317 1784 21.0

1,376.0 314 1,640 1 0 1 2 -304 1628 20.1

1,374.0 250 1,076 1 1 -249 1075 16.8

1,372.6 204 758 0 0 -204 758 14.4

1,372.0 185 641 0 0 -185 641 13.4

1,370.0 120 336 0 0 -120 336 10.1

1,368.0 7 2 144 0 0 -72 144 6.7

1,366.0 3 6 3 6 0 0 -36 3 6 3.4

1,364.0 0 0 0 0 0 0 0.0

1 Elevation of reservoir water surface. (Project vetical datum, near NGVD29).

2 Original reservoir surface area.

3 Original reservoir capacity recomputed using ACAP.

4 Reservoir surface area from 2009 survey.

5 Reservoir 2009 capacity computed using ACAP.

6 Area difference between original and 2009 survey = column (3) - column (5).

7 Volume difference between original and 2009 survey = column (4) - column (5).

8 Depth of reservoir expressed in percentage of total depth, 59.6 feet.

Table 2 - Tom Steed Reservoir survey results.
27

2009 Reservoir Analyses

Results of the 2009 Tom Steed Reservoir area and capacity computations are 

listed in Table 1 and columns 4 and 5 of Table 2. Columns 2 and 3 of Table 2 list 

the original area and capacity values. For this study the original capacities were 

recomputed using the same program as used to compute the 2009 capacities, 

ACAP (Reclamation, 1985). Only limited information was located on how the 

original surface areas and capacities were developed, but a footnote on one table 

indicated contour surface areas were measured from a 1975 survey and USGS 

quad contours that were at 10-foot intervals. Column 7 lists the capacity 

differences between the original and 2009 surveys. Figure 14 is a plot of the Tom 

Steed Reservoir surface area and capacity values for the surveys and illustrates the 

differences. The comparisons show that the total reservoir capacity in 2009 was

197,347 acre-feet or only 16 acre-feet less than the original volume at maximum 

reservoir elevation 1,423.6. It must be noted that the 2009 area and capacity 

tables were generated assuming no surface area change since the 1975 or original 

survey at elevation 1,412.0 and above. Column 6 lists the surface area differences 

between the original and 2009 surveys. Assuming no change at elevation 1,412.0 

and above is not entirely accurate, but any loss due to sediment deposition above 

this elevation is not likely to be significant since the reservoir has never operated 

above elevation 1,415 and rarely operates above elevation 1,412. Also, only the

limited detailed information on the actual reservoir topography in these upper 

elevation areas was available for the 2009 study.

During the planning phase for this reservoir, the original estimated 100 year 

sediment accumulation for Tom Steed Reservoir was 17,000 acre-feet from 

elevation 1,414.0 and below. Of this amount it was estimated that 11,700 acrefeet would deposit above pool elevation 1,386.3 meaning 5,300 acre-feet would 

be deposited below the inactive reservoir area below elevation 1,386.3. From 

Table 2, a comparison of the original and 2009 results show that for the first 34 

years of reservoir operations 4,150 acre-feet of sediment has already deposited 

below elevation 1,386.3. As stated previous data comparisons between the 

original and the 2009 survey data may be statistically invalid, but the 2009 study 

did measure a significantly smaller inactive and dead storage capacity than 

originally computed. The 2009 study measured a minimum bottom elevation of 

1,372.6 compared to the original minimum bottom elevation of 1,364.0 or nearly 

9 feet of sediment accumulation near the dam. During the 2009 data collection a 

weighted probe was dropped from the boat to confirm depth sounder readings. 

The light weighted probe sunk well over a foot into the reservoir bottom sediment

deposits indicating the material was not very consolidated at this time. Future 

build up of this material near the dam will eventually affect the outlet operations. 

Future collection will be required to better monitor and project the sediment 

buildup at the dam and throughout the reservoir. 
28

The results of the 2009 Tom Steed Reservoir study provide up-to-date surface 

area and capacity information for the reservoir from elevation 1,412.0 and below. 

This study had enough information to develop the current surface areas and 

resulting capacity as presented in this report. Aerial collection would be required 

for total reservoir topography development.

References

American Society of Civil Engineers, 1962. Nomenclature for Hydraulics, ASCE 

Headquarters, New York.

Bureau of Reclamation, 1981. Project Data, Denver Office, Denver CO.

Bureau of Reclamation, 1985. Surface Water Branch, ACAP85 User's Manual, 

Technical Service Center, Denver CO.

Bureau of Reclamation, 1987(a). Guide for Preparation of Standing Operating 

Procedures for Bureau of Reclamation Dams and Reservoirs, U.S. Government 

Printing Office, Denver, CO.

Bureau of Reclamation, 1987(b). Design of Small Dams, U.S. Government 

Printing Office, Denver CO.

Bureau of Reclamation July 1998. Standing Operating Procedures (SOP), 

Mountain Park Dam and Tom Steed Reservoir, Mountain Park Project, 

Oklahoma, GP Region, Billings, MT.

Bureau of Reclamation, June 2009. Tom Steed Reservoir Area and Capacity 

Tables, Mountain Park Project, Great Plains Region, Billings, MT.

Corps of Engineers, January 2002. Engineer and Design Hydrographic

Surveying, EM 1110-2-1003, Department of the Army, Washington DC,

(www.usace.army.mil/inet/usace-docs/eng-manuals/em1110-2-1003/toc.htm).

ESRI, 2010. Environmental Systems Research Institute, Inc. (www.esri.com)

Ferrari, R.L. and Collins, K. (2006). Reservoir Survey and Data Analysis, 

Chapter 9, Erosion and Sedimentation Manual, Bureau of Reclamation, 

Sedimentation and River Hydraulics Group. Denver, Colorado.

www.usbr.gov/pmts/sediment

USDA, 2010. United States Department of Agriculture, Online GIS Services,

http://datagateway.nrcs.usda.gov/