KIRWIN RESERVOIR

1996 SEDIMENTATION

SURVEY

FOR TH

j.

U.S. Department of the Interior

Bureau of Reclamation
REPORT DOCUMENTATION PAGE I OMBNo.O4-O188

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1. AGENCY USE ONLY (Leave Blank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED

August 1997 Final ___________________________

4. TITLE AND SUBTITLE 5. FUNDING NUMBERS

Kirwin Reservoir PR

1996 Sedimentation Survey

6. AUTHOR(S)

Ronald L. Ferrari ____________________________

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION

REPORT NUMBER

Bureau of Reclamation, Technical Service Center, Denver CO 80225-0007 ____________________________

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSORING/MONITORING

AGENCY REPORT NUMBER

Bureau of Reclamation, Denver Federal Center, P0 Box 25007, DIBR Denver CO 80225-0007 ___________________________

11. SUPPLEMENTARY NOTES

Hard copy available at Bureau of Reclamation Technical Service Center, Denver, Colorado

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Available from the National Technical Information Service,

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13. ABSTRACT (Maximum 200 words)

The Bureau of Reclamation (Reclamation) surveyed the underwater area of Kirwin Reservoir in May 1996 to develop

a topographic map and compute a present storage-elevation relationship (area-capacity tables). The data were also

used to calculate reservoir capacity lost due to sediment accumulation since dam closure on March 7, 1955. The

survey used sonic depth recording equipment interfaced with a global positioning system (GPS) that gave continuous

sounding positions throughout the underwater portion of the reservoir. Reservoir topography was developed by a

computer program using collected and projected underwater data along with above-water topography determined

from digitized contour lines from the U.S. Geological Survey quadrangle (USGS quad) maps. The USGS quads of

the reservoir area were developed from aerial photography obtained in 1958 and 1971. The new topographic map of

Kirwin Reservoir is a combination of digitized contours and 1996 underwater measured topography.

As of May 23, 1996, at top of active conservation elevation (feet) 1,729.25, the surface area was 5,071 acres, the total

capacity was 98,154 acre-feet, and the active capacity was 89,639 acre-feet. Since initial filling in March 1955, about

1,278 acre-feet of sediment have accumulated in Kirwin Reservoir below elevation 1729.25, resulting in a 1.28

percent loss in reservoir volume. Since 1955, the estimated average annual rate of reservoir capacity lost to

sediment_accumulation_is_31.1_acre-feet. _____________________

14. SUBJECT TERMS 15. NUMBER OF PAGES

21

reservoir area and capacity! sedimentation/ reservoi r surveys! sonar! sediment

distribution! contour area' reservoir area' sedimentation survey! global positioning system 16. PRICE CODE

17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFiCATION 20. LIMITATION OF ABSTRACT

OF REPORT OF ThIS PAGE OF ABSTRACT

UL UL UL UL

NSN 7540-01-280-5500 Standard Form 298 (Rev. 2-89)

Prescribed by ANSI Std. 239-18

298-102
KIRWIN RESERVOIR

1996 SEDIMENTATION SURVEY

by

Ronald L. Ferrari

Sedimentation and River Hydraulics Group

Water Resources Services

Technical Service Center

Denver, Colorado

August 1997

ACKNOWLEDGMENTS

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

of the Technical Service Center (TSC) prepared and published this report. Ronald

Ferrari and James Melena of the TSC conducted the hydrographic survey. Special thanks

to Mr. David Grooms, of the Great Plains Region, for the field assistance during the

hydrographic survey. Ronald Ferrari completed the data processing needed to generate

the new topographic map and area-capacity tables. Sharon Nuanes of the TSC completed

the USGS contour digitizing and was consulted during the map development. James

Melena of TSC performed the technical peer review of this documentation.

U.S. Department of the Interior

Mission Statement

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 Tribes.

The information contained in this report regarding commercial products or firms may not

be used for advertising or promotional purposes and is not to be construed as an

endorsement of any product or firm by Reclamation.

The information contained in this report was developed for Reclamation; no warranty

as to its accuracy, usefulness, or completeness is expressed or implied.

11

CONTENTS

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Introduction 1

Summary and conclusions 2

Reservoir operations 2

Hydrographic survey equipment and method 3

GPS Technology and Equipment 3

Survey Method and Equipment 5

Reservoir area and capacity 6

Topography Development 6

Development of 1996 Contour Areas 8

1996 Storage Capacity 8

Sediment analyses 9

References 11

TABLES

Table

1 Reservoir sediment data summary 12

2 Summary of 1996 survey results 14

Figure

FIGURES

1 Kirwin Reservoir location map 15

2 Kirwin dam, plan and section 16

3 Kirwin Reservoir end-of-month elevations for 1955 through 1996 17

4 Kirwin 1996 underwater collected data 18

5 Kirwin underwater 1996 collected data and added points 19

6 Kirwin Reservoir topographic map 20

7 1996 area and capacity curves 21

111

INTRODUCTION

Kirwin Dam and Reservoir are principal features of the Solomon Division Kirwin Unit of the

Pick-Sloan Missouri Basin Program. Additional unit features are the Kirwin main, north, and

south canals, the laterals, and the drainage systems. Kirwin Dam and Reservoir, on the North

Fork Solomon River, are located in Phillips County of north central Kansas less than one mile

upstream of the town of Kirwin (fig. 1).

Kirwin Dam was constructed between 1952 through 1955 with first storage on March 7, 1955.

The dam is a rolled earthfihl structure, whose dimensions are (fig. 2):

• Hydraulic height' 97.3 feet

• Structural height 169.0 feet

• Top width 30 feet

• Crest length 12,646 feet

• Crest elevation 1,779 feet

Kirwin Dam's spillway, located in the right abutment about 4,000 feet southeast of the old river

channel, is an ungated, overflow structure. It consists of a 1,200-foot long, unlined, shallow

approach channel with approximate bottom elevation of 1720 and width of 90 feet. This

approach channel provides a passageway for flood control releases when the reservoir water

surface is below elevation 1750. 2 The spillway crest at elevation 1757.3 is 400 feet wide. The

center portion of the spillway crest contains fifteen 5- by 5-foot gated sluiceways which provide

flood control releases. Access to the spillway gallery, which contains the controls for operation

of the sluiceway gates, is provided on each side of the spillway through the access house.

Spiliway flows through the sluiceways are confined within a chute and are discharged to a 350-

foot wide, 95-foot long stilling basin whose floor elevation is 1658.0 feet. The discharge

capacity is 96,000 cubic feet per second (cfs) at reservoir elevation 1,773.0, (Bureau of

Reclamation, 1981).

The gated outlet works is a concrete conduit located approximately 150 feet upstream from the

centerline of the dam. The outlet works serves as both a river and canal outlet facility. The

releases are made from a stilling well located near the downstream side of the dam. The

discharge capacity, at reservoir elevation 1,701.0, is 175 cfs to the canal and 100 cfs to the river.

Kirwin Reservoir stores water from the North Fork Solomon River and Bow Creek. The

drainage area above the dam is 1,367 square miles, ranging from elevation 1,697.0, top of

inactive pool, to greater than elevation 3,450 at its headwaters. The reservoir length at

elevation 1,729 is around 13.8 miles, including the 8.7-mile North Fork Solomon River and the

1-mile Bow Creek. The average width of the reservoir is 0.6 mile.

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.

2A11 elevation levels are shown in feet.

SUMMARY AND CONCLUSIONS

This Reclamation report presents the 1996 results of the first extensive survey of Kirwin

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

• develop reservoir topography

• compute area-capacity relationships

• estimate storage depletion caused by sediment deposition since Kirwin Dam closure

The bathymetric survey was run using sonic depth recording equipment interfaced with a

differential global positioning system (DGPS) capable of determining sounding locations within

the reservoir. The system continuously recorded depth and horizontal coordinates of the survey

boat as it was navigated along grid lines covering Kirwin Reservoir. The positioning system

provided information to allow the boat operator to maintain 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 true reservoir bottom elevations.

The 1996 underwater surface areas at predetermined contour intervals were generated by a

computer graphics program using the underwater collected data. The above-water reservoir

contours were digitized from U.S. Geological Survey 7.5 minute quadrangle (USGS quad) maps

of Kirwin Reservoir. The new topographic map of Kirwin Reservoir is a combination of the

digitized and underwater measured topography. The area and capacity tables were produced by a

computer program that uses measured contour surface areas and a curve-fitting technique to

compute area and capacity at prescribed elevation increments. The 1996 area and capacity tables

were generated using the 1996 measured areas at elevation 1720.0 and less and the original

measured areas for elevation 1725.0 and greater.

Table 1 contains a summary of Kirwin Reservoir's watershed characteristics for the 1996 survey.

The 1996 survey determined that the reservoir has a storage capacity of 98,154 acre-feet and a

surface area of 5,071 acres at reservoir elevation 1,729.25 feet. Since closure in 1955, the

reservoir has accumulated a sediment volume of 1,278 acre-feet below reservoir elevation

1,729.25. This volume represents a 1.28 percent loss in capacity and an average annual loss of

31.1 acre-feet.

RESERVOIR OPERATIONS

Kirwin Reservoir is primarily an irrigation and flood protection facility (the following values are

from May 1996 area-capacity tables):

• 198,467 acre-feet of surcharge storage between elevations 1,757.3 and 1,773.0.

• 215,136 acre-feet of flood control between elevations 1,729.25 and 1,757.3.

• 89,639 acre-feet of active conservation storage between elevations 1,697.0 and 1,729.25.

• 3,546 acre-feet of inactive storage between elevations 1,693.0 and 1,697.0.

• 4,969 acre-feet of dead storage below elevation 1,693.0.

2
The Kirwin Reservoir inflow and end-of-month stage records in table 1 show the annual (January

through December) inflow and fluctuation for the operation period March 1955 through May

1996. The average annual reservoir inflow for this operation period was 34,338 acre-feet. Figure

3 show the extreme storage fluctuations of Kirwin Reservoir when in 1957 it ranged from

elevation 1,694.8 to 1,729.5 to the maximum elevation on record, elevation 1,737.0, on June 2,

1995. The records also show the reservoir has operated in the inactive zones, elevation 1697.0

and below, during the years of 1978, 1980 through 1985, and 1990 through 1992, and at a low

storage content, below elevation 1710, between the years 1975 through 1993. Prior to dam

closure, records for 1920 through 1954 calculated a mean annual flow of 56,100 acre-feet at the

dam

HYDROGRAPHIC SURVEY EQUIPMENT AND METHOD

The hydrographic survey equipment was mounted in the cabin of a 24-foot tn-hull aluminum

vessel equipped with twin in-board motors. The hydrographic system contained on the survey

vessel consisted of a global positioning system (GPS) receiver with a built-in radio and an

onmidirectional antenna, a depth sounder, a helmsman display for navigation, a plotter, a

computer, and hydrographic system software for collecting underwater data. Power to the

equipment was supplied by an on-board generator.

The shore equipment included a second GPS receiver with a built-in radio and an

omnidirectional antenna. The GPS receiver and antenna were mounted on a survey tripod over a

known datum point. The power for the shore unit was provided by a 12-volt battery.

GPS Technology and Equipment

The positioning system used at Kirwin Reservoir was Navigation Satellite Timing and Ranging

(NAVSTAR) GPS; an all-weather, radio-based, satellite navigation system that enables users to

accurately determine three-dimensional position. The NAVSTAR system's primary mission is to

provide passive global positioning and navigation for land, air, and sea based strategic and

tactical forces and is operated and maintained by the Department of Defense (DOD). The GPS

receiver measures the distances between the satellites and itself and determines the receiver's

position from intersections of the multiple range vectors. Distances are determined by accurately

measuring the time a signal pulse takes to travel from the satellite to the receiver.

The NAVSTAR system consists of three segments:

The space segment is a network of 24 satellites maintained in precise orbit about 10,900

nautical miles above the earth, each completing an orbit every 12 hours.

The ground control segment tracks the satellites, determining their precise orbits.

Periodically, the ground control segment transmits correction and other system data to all

the satellites, and the data are then retransmitted to the user segment.
• The user segment includes the GPS receivers which measure the broadcasts from the

satellites and calculate the position of the receivers.

The GPS receivers use the satellites as reference points for triangulating their position on earth.

The position is calculated from distance measurements to the satellites that are determined by

how long a radio signal takes to reach the receiver from the satellite. To calculate the receiver's

position on earth, the satellite distance and the satellite's position in space are needed. The

satellites transmit signals to the GPS receivers for distance measurements along with the data

messages about their exact orbital location and operational status. The satellites transmit two "L"

band frequencies (called Li and L2) for the distance measurement signal. At least four satellite

observations are required to mathematically solve for the four unknown receiver parameters

(latitude, longitude, altitude, and time; the time unknown is caused by the clock error between

the expensive satellite atomic clocks and the imperfect clocks in the GPS receivers (for

hydrographic surveying the altitude, Kirwin's water surface elevation parameter was known,

which realistically meant only three satellite observations were needed to track the survey vessel;

during the Kirwin Reservoir survey, the best 6 available satellites were used for position

calculations).

The GPS receiver's absolute position is not as accurate as it appears in theory because of the

function of range measurement precision and the geometric position of the satellites. Precision is

affected by several factors----time, because of the clock differences, and atmospheric delays

caused by the effect on the radio signal of the ionosphere. Geometric dilution of precision

(GDOP) describes the geometrical uncertainty and is a function of the relative geometry of the

satellites and the user. Generally, the closer together in angle two satellites are from the receiver,

the greater the GDOP. GDOP is broken into components: position dilution of precision (x,y,z)

(PDOP) and horizontal dilution of precision (x,y) (HDOP). The components are based only on

the geometry of the satellites. The PDOP and HDOP were monitored during the Kirwin

Reservoir Survey, and for the majority of the time they were less than 3, which is within the

acceptable limits of horizontal accuracy for Class 1 and 2 level surveys (Corps of Engineers,

1991).

An additional and larger error source in GPS collection is caused by false signal projection,

called selective availability (S/A). The DOD implements S/A to discourage the use of the

satellite system as a guidance tool by hostile forces. Positions determined by a single receiver

when S/A is active can have errors of up to 100 meters.

A method of collection to resolve or cancel the inherent errors of GPS (satellite position or S/A,

clock differences, atmospheric delay, etc.) is called differential GPS (DGPS). DGPS was used

during the Kirwin Reservoir survey to determine positions of the moving survey vessel in real

time. DGPS determines the position of one receiver in reference to another and is a method of

increasing position accuracies by eliminating or minimizing the uncertainties. Differential

positioning is not concerned with the absolute position of each unit but with the relative

difference between the positions of two units, which are simultaneously observing the same

satellites. The inherent errors are mostly canceled because the satellite transmission is essentially

the same at both receivers.

4
At a known geographical benchmark, one GPS receiver is programmed with the known

coordinates and stationed over the geographical benchmark. This receiver, known as the master

or reference unit, remains over the known benchmark, monitors the movement of the satellites,

and calculates its apparent geographical position by direct reception from the satellites. The

inherent errors in the satellite position are determined relative to the master receiver's

programmed position, and the necessary corrections or differences are transmitted to the mobile

GPS receiver on the survey vessel. For the Kirwin Reservoir, position corrections were

determined by the master receiver and transmitted via an ultra-high frequency (UHF) radio link

every 3 seconds to the survey vessel mobile receiver. The survey vessel's GPS receiver used the

corrections along with the satellite information it received to determine the vessel's differential

location. Using DGPS resulted in positional accuracies of I to 2 meters for the moving vessel

compared to positional accuracies of 100 meters with a single receiver.

The Technical Service Center (TSC) mobile and reference GPS units are identical in construction

and consist of a 6-channel Li coarse acquisition (CIA) code continuous parallel tracking receiver,

an internal modem, and a UHF radio transceiver. The differential corrections from the reference

station to the mobile station are transmitted using the industry standard Radio Technical

Commission for Maritime Services (RCTM) message protocol via the UHF radio link. The

programming to the mobile or reference GPS unit is accomplished by entering necessary

information via a notebook computer. The TSC's GPS system has the capability of establishing

or confirming the land base control points by using notebook computers for logging data and

post-processing software. The GPS collection system has the capability of collecting the data in

1927 or 1983 NAD (North American Datums) in the surveyed area's state plane coordinate

system's zone. For Kirwin Reservoir, the data were collected in the Kansas's 1927 NAD north

state plane zone.

Survey Method and Equipment

The Kirwin Reservoir hydrographic survey was conducted on May 20 through May 23, 1996 at

reservoir water surface elevation 1,731.2. The bathymetric survey was run using sonic depth

recording equipment interfaced with a DGPS capable of determining sounding locations within

the reservoir. The survey system software continuously recorded reservoir depths and horizontal

coordinates as the survey boat moved across close-spaced grid lines covering the reservoir area.

Most of the transects (grid lines) were run primarily in a north-south direction. Data were also

collected along the shore as the boat traversed to the next transect and as it maneuvered in the

open areas between the trees. Thick tree growth within the reservoir prevented the boat from

surveying some areas, such as those near the shoreline, shallow water areas in the main body, and

coves or inlets along the banks. In some areas the growth was so thick the survey vessel ended

the collection in 18 to 20 feet of water or at approximately bottom elevation 1712. This included

large areas of the reservoir around Bow Creek and the large cove areas of the reservoir that exist

at reservoir elevation 1720 and above. Figure 4 illustrates the reservoir area covered by the 1996

underwater survey versus the contours digitized from the USGS quad maps (the light outside

dashed line represents the elevation 1729 contour and the heavy inside dashed line represents the

elevation 1720 contour). The survey vessel's guidance system gave directions to the boat

operator to assist in maintaining course along these predetermined lines. During each run, the

5
depth and position data were recorded on the notebook computer hard drive for subsequent

processing by TSC personnel. The underwater data set includes 24,328 data points. A graph

plotter was used in the field to track the boat and ensure adequate coverage during the collection

process. The water surface elevation recorded by a Reclamation gage during the time of

collection was used to convert the sonic depth measurements to true lake bottom elevations.

For stationing the master GPS unit, there were no known benchmarks or datums that overlooked

the reservoir. For the underwater collection the hydrographic survey crew established a datum

using the hydrographic GPS units and software. In establishing the control for the reference

datum the second order National Geodetic Survey benchmark (Kirwin), located just north of the

reservoir, was used. The control was brought in from the Kirwin benchmark to a pipe on the

dam marked 75+99.5, 17.5US. This method calculated 1927 NAD state plane coordinates of

North 488,248.337 and East 1,681,399.747 at this location. The shore-based master GPS unit,

which transmits the correction information to the mobile GPS unit on the survey vessel, was

stationed at this new datum site throughout the survey. This location was chosen because it was

accessible and overlooked the reservoir. The location allowed for good radio transmission of the

differential corrections to the mobile survey vessel throughout the reservoir survey. During post

processing of the collected data, the few collected points without differential correction were

removed.

The underwater data were collected by a depth sounder which was calibrated by lowering a

deflector plate below the boat by cables with known depths marked by beads. The depth sounder

was calibrated by adjusting the speed of sound, which can vary with density, salinity,

temperature, turbidity, and other conditions. The collected data were digitally transmitted to the

computer collection system via a RS-232 port. The depth sounder also produces an analog hard

copy chart of the measured depths. These graphed analog charts were printed for all survey lines

as the data were collected and recorded by the computer. The charts were analyzed during postprocessing, and when the analog charted depths indicated a difference from the recorded

computer bottom depths, the computer data files were modified.

RESERVOIR AREA AND CAPACITY

Topography Development

The topography of Kirwin Reservoir was developed from the 1996 collected underwater data and

from the USGS quad maps. The upper contours of Kirwin Reservoir were developed by

digitizing the contour lines of elevation 1,720.0, 1729.0, 1730.0, 1740.0, and 1757.0, from the

USGS quad maps that covered the Kirwin Reservoir area. The USGS quad maps were

developed from aerial photography dated 1958 and 1971. ARC/INFO V7.0.2 geographic

information system software was used to digitize the USGS quad contours. The digitized

contours were transformed to Kansas' NAD 1927 north state plane coordinates using the

ARC/INFO PROJECT command.

6
Following are the ARCiTNFO resulting digitized areas from the USGS quads versus the original

reported areas reported in March of 1955:

(1) USGS digitized 1720 contour area was 3,637 acres, or 99.8% of the original 3,757-acre area

(2) USGS digitized 1729 contour area was 4,973 acres, or 98.9% of the original 5,030-acre area

(3) USGS digitized 1730 contour area was 5,289 acres, or 101.9% of the original 5,190-acre area

(4) USGS digitized 1740 contour area was 6,964 acres, or 100% of the original 6,965-acre area

(5) USGS digitized 1757 contour area was 10,257 acres, or 97% of the original 10,550-acre area.

It is assumed that the area differences are due to the quad scale (one inch equals two thousand

feet) and the different methods of digitizing the contour areas. The underwater topography on

the USGS quad maps, elevation 1720 and below, was noted to be from a Reclamation map dated

1952.

The elevation 1,729.0 contour digitized from USGS quad maps was used to perform a clip of the

Kirwin Reservoir triangular irregular network (T[N) such that interpolation was not allowed to

occur outside the 1,729.0 contour. This complete contour was selected since it was the elevation

that most nearly enclosed the 1996 underwater data collected at reservoir elevation 1731.2. This

clip was performed using the hardclip option of the ARC/[NFO CREATETIN command. Using

ARCEDIT, the underwater collected data and the digitized 1720 and 1729 contours from the

USGS quad maps were plotted (figure 4). The plot found that the majority of the underwater

data occurred completely within the elevation 1729 clip and required only minor adjustments to

enclose all collected data.

For developing the 1996 Kirwin Reservoir contour map and calculating the surface areas, data

information was needed for the underwater reservoir areas not surveyed. Using ARCEDIT, the

digitized elevation 1720 USGS quad contour and the 1996 underwater collected data layers were

overlaid or plotted on-screen. Using ARCEDIT, elevation points were added to develop

reservoir contours and to calculate surface areas for elevation 1720 and below. Location of these

points was determined by using the 1720 contour as the pattern and the elevation information of

the individual 1996 collected data points. The majority of the additional points used the 1720

contour pattern to determine where they were to be placed assuming no change, but when the

1996 collected data indicated that a change had occurred, the placement of the data points

reflected the underwater reservoir conditions. In the cove areas of the reservoir additional points

were also placed to develop the contours below elevation 1720. Figure 5 has the resulting

contours for elevation 1710 and 1720 along with the digitized 1720 and 1729 contours, 1996

collected underwater data, and additional data points.

Contours for elevations 1720.0 and below were computed from the developed underwater data

using the TIN surface modeling package within ARC/INFO. The underwater survey data were

collected in the Kansas north zone state plane coordinates in NAD 1927 (a TIN is a set of

adjacent, non-overlapping triangles computed from irregularly spaced points with x,y coordinates

and z values). TIN was designed to deal with continuous data such as elevations. The TIN

software uses a method known as Delaunay's criteria for triangulation. Triangles are formed

between all data points including all boundary points. This method preserves all collected survey

points. The method requires that a circle drawn through the three nodes of a triangle will contain

7
no other point, meaning that sample points are connected to their nearest neighbors to form

triangles using all collected data. Elevation contours are then interpolated along the triangle

elements. The TiN method is discussed in great detail in the ARC/iNFO V7.0.2 Users

Documentation.

In creating the TIN, points that fell within a set distance of each other were weeded out to

eliminate flat triangular elements (flat triangles occur where all three points making up a triangle

have the same elevation). Elimination of redundant points helped to improve the performance of

the contouring process and helped create more continuous contours in the lower elevations of the

reservoir.

The linear interpolation option of the ARC/INFO TINCONTOUR command was used to

interpolate contours from the Kirwin Reservoir TIN. In addition, the contours were generalized

by weeding out vertices along the contours. This generalization process improved the

presentability of the resulting contours by removing veiy small variations in the contour lines.

This generalization had little bearing on the computation of surface areas and volumes for Kirwin

Reservoir. The contour topography at 2-foot intervals is presented on figure 6, drawing number

371 -D-364.

Development of 1996 Contour Areas

The 1996 contour surface areas for Kirwin Reservoir were computed at 2-foot increments, from

elevation 1,680.4 to 1,720.0, using the Kirwin Reservoir TIN discussed above. The 1996 survey

measured the minimum reservoir elevation at 1,680.4 feet. These calculations were performed

using the ARC/INFO VOLUME command. This command computes areas at user specified

elevations directly from the TIN and takes into consideration all regions of equal elevation. As

discussed in the survey method and equipment section, large areas of the underwater portion of

the reservoir were not surveyed due to the thick tree growth. This accounts for the fact that the

1996 areas were only computed for elevation 1,720.0 and below. Due to the lack of 1996 survey

data the fmal 1996 area computations assumed no change in surface area from elevation 1725

and above.

1996 Storage Capacity

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

the area-capacity computer program ACAP85 (Bureau of Reclamation, 1985). Surface areas at

2-foot contour intervals from minimum reservoir elevation 1,680.4 to elevation 1,720.0 and the

original surface areas at 5-foot contour intervals from elevation 1,725.0 to 1,770.0 and 1,773.0

were used as the control parameters for computing the Kirwin Reservoir capacity. The program

can compute an area and capacity at elevation increments 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,

which was set at 0.00000 1 for Kirwin Reservoir. This capacity equation is then used over the

full range of intervals fitting within this 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) tests the fit until it also exceeds the error limit. Thus, the capacity curve

8
is defined by a series of curves, each fitting a certain region of data. Final area equations are

derived by differentiating the capacity equations, which are of second order polynomial form:

y a1 + a-,x + a3x2

where:

y capacity

x elevation above a reference base

a1 intercept

a, and a3 coefficients

Results of the 1996 Kirwin Reservoir area and capacity computations are listed in table 1 and

columns (4) and (5) of table 2. Listed in columns (2) and (3) of table 2 are the original surface

areas and recomputed capacity values. A separate set of 1996 area and capacity tables has been

published for the 0.01-, 0.1-, and 1-foot elevation increments (Bureau of Reclamation 1996). A

description of the computations and coefficients output from the ACAP85 program is included

with these tables. Both the original and 1996 area-capacity curves are plotted on figure 7. As of

May 1996, at elevation 1,729.25, the surface area was 5,071 acres with a total capacity of 98,154

acre-feet and an active capacity of 89,639 acre-feet.

SEDIMENT ANALYSES

Sediments have accumulated in Kirwin Reservoir to a total volume of 1,278 acre-feet since dam

closure in March 1955. This volume was calculated at top of reservoir water supply elevation

1,729.25. It must be noted that the 1996 underwater survey was conducted at water surface

elevation 1731.2, but that the final product relied on the original measured surface areas at

elevation 1725.0 and greater for computing the 1996 reservoir area and capacity tables. Column

6 of table 2 gives the measured sediment volume by elevation, and the area curve on figure 7

illustrates the resulting measured surface areas and calculated capacities. This table and figure

illustrate that the majority of the sediment deposit is in the lower elevations of the reservoir. The

average annual rate of sediment deposition between closure and May 1996 (41 .1 years) was 31.1

acre-feet per year. The storage loss in terms of percent of original storage capacity was 1.28

percent. Tables 1 and 2 contain the Kirwin Reservoir sediment accumulation and water storage

data based on the 1996 resurvey.

The original 50-year sediment deposition estimate was 10,750 acre-feet, which was projected to

settle below elevation 1729.25. The 1996 study found very little sediment accumulation, (1,278

acre-feet) within Kirwin Reservoir considering the size of the drainage basin and the large

projected estimate. Prior to reservoir impoundment, a sediment range line network was

established for monitoring sediment inflow. A review of the range lines that were resurveyed

found little change except in the original river channels. The collected information indicated that

there was some sediment inflow, but that there was not enough information for conclusive

9
results. The computed sediment accumulation was very similar to that found in Webster

Reservoir, which is located southwest of Kirwin Reservoir on the South Fork of the Solomon

River.

Table 1 gives some clues as to why the sediment accumulation is lower than original projections.

The mean annual runoff of the 1,367-square-mile-basin, for the 41.1 year period of record, was

34,338 acre-feet, or only 0.47 inches. Prior to dam closure, the records for 1920 through 1954

calculated a mean annual flow of 56,100 acre-feet at the dam. Lovewell Reservoir, located on

White Rock Creek approximately 85 miles northeast of Kirwin Reservoir, had a calculated mean

annual runoff of 3.4 inches. Kirwin Reservoir drainage basin has a much lower runoff, reflecting

the lower sediment contribution. Another factor is illustrated in item 45 of table 1 and on figure

3, which depicts the range in reservoir operation. The reservoir has operated at full conditions in

a few years--above elevation 1729.25--but in many more years the reservoir has operated at low

reservoir content, below elevation 1710, and there have even been years when it operated in the

inactive zone, below elevation 1697. These low reservoir operating conditions probably have

caused some of the upper-reservoir accumulated sediments to move towards the dam, and some

of this accumulated material is assumed to eventually be flushed downstream through the outlet

works.

The measured surface areas, column 2 and 4, and the calculated sediment volume, column 6 of

table 2, along with the area curves of figure 7 show some interesting results. The table shows the

1996 surface areas at less than the original areas below elevation 1705 due to sediment

accumulation and then show 1996 surface areas larger than the original areas at elevations 1710

and 1715. The resulting reservoir capacity loss due to sediment distribution is a maximum of

1,741 acre-feet at elevation 1710 and a minimum of 1,025 acre-feet at elevation 1720. These

results are explained by comparing the new reservoir topography at elevation 1710 with the

original topography on the USGS quad map and by examining past reservoir operations. Since

dam closure, the reservoir has operated at elevation 1710 or below around 40 percent of the time.

Comparing the original and the 1996 topography, it appears that a second inflow channel has

developed just above the confluence of Bow Creek and the Solomon River. This second channel

explains why the 1996 surface areas--approximately elevation 1710--are larger than the original

areas. It is assumed this original reservoir bottom material was eroded downstream by river

inflows during low reservoir elevations, and deposited downstream near the dam. For

determining the sediment contribution from the drainage area over the 41.1 years of reservoir

operation, the value at reservoir elevation l729.25--l,278 acre-feet--was used.

10

REFERENCES

American Society of Civil Engineers, 1962. Nomenclaturefor Hydraulics, ASCE

Headquarters, New York.

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

__________________ 1985. Surface Water Branch, ACAP8S User's Manual, Technical

Service Center, Denver, Colorado.

__________________ 1 987a. Guide for Preparation of Standing Operating Procedures for

Bureau of Reclamation Datns and Reservoirs, U.S. Government Printing Office, Denver, CO.

Denver, CO.

1987b. Design of Small Dams, U.S. Government Printing Office,

__________________ May 1996. Denver Office, Kirwin Reservoir Area and Capacity Tables,

Bostwick Division, Great Plains Region, Denver, CO.

Corps of Engineers, March 1991. Application of D?fferential Global Positioning System for

Hydrographic Survey and Dredge Positioning, ETL 1110-7-5 (FR), Department of the Army,

Washington, DC.

Environmental Systems Research Institute, Inc., 1992. ARC Command Reftrences.

11

RESERVOIR SEDIMENT

DATA SUMMARY Kirwin Reservoir

NAME OF RESERVOIR 1

DATA SHEET NO.

O 1. OWNER Bureau of Reclamation 2. STREAM North Fork Solomon River 3. STATE Kansas

A 4. SEC. 33 TM?. 4$ RANGE 16W 5. NEAREST P.O. Kirwin 6. COUNTY Phillips

N 7. LAT 39° 39' 49° LONG 99° 07' 29" 8. TOP OF DAM ELEVATION 1,779.0 9. SPILLWAY CREST EL. 1757.3

H 10. STORAGE 11. ELEVATION 12. ORIGINAL 13. ORIGINAL 14. GROSS STORAGE 15. DATE

E ALLOCATION TOP OF POOL SURFACE AREA, AC CAPACITY, AR ACRE- FEET STORAGE

S BEGAN

E

R

a. SURCHARGE 1,773.0 14.660 198,470 513,020

v

b. FLOOD CONTROL 1,757.3 10,640 215,115 314,550

3/07/55

O c. POWER

I d. WATER SUPPLY 1,729.25 5,071 89,650 99,435 16. OATE

R a. IRRIGATION NORMAL

OPERATION

f. INACTIVE 1,697.0 1,010 3,400 9,785

g. DEAD 1,693.0 720 6,385 6,385 3/55

-

17. LENGTH OF RESERVOIR 13.8' MILES AVG. WIDTH OF RESERVOIR 0.6 MILES

B 18. TOTAL DRAINAGE AREA 1,367 SQUARE MILES 22. MEAN ANNUAL PRECIPITATION 23.72 INCHES

A 19. NET SEDIMENT CONTRIBUTING AREA 1,367 SQUARE MILES 23. MEAN ANNUAL RUNOFF 0.47 INCHES

20. LENGTH MILES AV. WIDTH MILES 24. MEAN ANNUAL RUNOFF 34,338k ACRE-FEET

•_ 21. MAX. ELEVATION 3.450 MIN. ELEVATION 1,697 25. ANNUAL TEMP. MEAN 54°F RANGE -22°F to 112°F5

S 26. DATE OF 27. 28. 29. TYPE OP 30. NO. OF 31. SURFACE 32. CAPACITY 33. C/I

U SURVEY PER. ACCL. SURVEY RANGES OR AREA, AC. ACRE-FEET RATIO AR/AR

R ________________ ___________________________________________________ ___________________________________

V

__________________

E 3/07/55 Contour (D) 5-ft 5,0716 99,4326 2.90

Y

D

5/23/96 41.1 41.1 Contour (0) 2-ft 5,071' 98,154' 2.86

A

26. DATE OF 34. PERIOD 35. PERIOD WATER INFLOW, ACRE FEET WATER INFLOW TO DATE, AR

T

SURVEY ANNUAL ______________________________

A

PRECIP.

______________

a. MEAN ANN.

_______________

b. MAX. ANN.

_____________

c. TOTAL

_

a. MEAN ANN. b. TOTAL

5/23/96 23.72 34,338 129,300 1,411,300 34,338 1,411,300

26. DATE OF 37. PERIOD CAPACITY LOSS, ACRE-FEET 38. TOTAL SEDIMENT DEPOSITS TO DATE, AR

SURVEY _______________

a. TOTAL

________________

b. AV. ANN.

_______________

c. /MI.-YR.

_____________

a. TOTAL

__________________

b. AV. ANNUAL

________________

C. /MI.-YR.

5/23/96 1,2788 31.1 .02 1,278 31.1 .02

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

SURVEY MT. (#/FT')

____________________________

a. PERIOD b. TOTAL TO

___________

a. AV.

_________________

b. TOTAL TO

________

a.

______

b.

5/23/96 .0318 1.288

26.

DATE

43. DEPTH DESIGNATION RANGE IN FEET BELOW ELEVATION

OF

SURVEY

PERCENT OF TOTAL SEDIMENT LOCATED WITHIN DEPTH DESIGNATION

26. 44. REACH DESIGNATION PERCENT OF TOTAL ORIGINAL LENGTH OF RESERVOIR

DATE

SURVEY

0-10 10-

20

20-

30

30-

40

40-

50

50-

60

60-

70

70-

80

80-

90

90-

100

100-

105

105-

110

110-

115

115-

120

120-

125

PERCENT OF TOTAL SEDIMENT LOCATED WITHIN REACH DESIGNATION

Table 1. - Reservoir sediment data summary (page 1 of 2).

12
45. RANGE IN RESERVOIR OPERATIONS

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

1955 1,693.2 1,675.6 21,300 1956 1,698.1 1,692.5 7,600

1957 1,729.5 1,694.8 123,100 1958 1,728.2 1,725.9 28,200

1959 1,727.9 1,724.0 23,300 1960 1,731,6 1,725.1 60.900

1961 1,732.1 1,725.4 60,900 1962 1,730.5 1,726.4 52,800

1963 1,728.8 1,724.9 33,500 1964 1,726.8 1,719.8 16.300

1965 1,730.4 1,719.7 82,000 1966 1,729.2 1,723.8 30,300

1967 1,726.2 1,723.6 29,900 1968 1,727.5 1,722.2 51,800

1969 1,732.0 1,727.4 69.300 1970 1,729.8 1,723.9 25,500

1971 1,725.8 1,718.6 19,800 1972 1,719.6 1,713.4 16.000

1973 1,718.0 1,710.8 30,900 1974 1,718.4 1,709.9 23,700

1975 1,722.4 1,710.5 57.200 1976 1,719.8 1,707.8 12,500

1977 1,711.6 1,700.7 20,000 1978 1,706.8 1,696.2 15.700

1979 1,708.3 1,699.7 23.800 1980 1,707.0 1,695.6 9,900

1981 1,697.5 1,695.4 3.900 1982 1,702.1 1,696.0 - 9,000

1983 1,705.5 1,696.8 9,700 1984 1,706.1 1,696.8 15.500

1985 1,706.3 1,697.0 17.200 1986 1,711.5 1,702.1 20.400

1987 1,715.3 1,704.7 36.300 1988 1,714.2 1,703.6 11.100

1989 1,707.4 1,700.1 12.200 1990 1,707.0 1,695.8 12.400

1991 1,697.8 1,695.5 3,800 1992 1,704.9 1,695.7 15,600

1993 1,735.1 1,704.9 129,300 1994 1,734.7 1,728.1 58,700

1995 1,737.1 1729.0 91.100 1996 1,731.2 1,730.2 18900

46. ELEVATION - AREA - CAPACITY DATA FOR 1996 CAPACITY

ELEVATION AREA CAPACITY ELEVATION AREA CAPACITY ELEVATION AREA CAPACITY

1680.4 0 0 1681 1.4 0 1682 31.8 17

1684 262.6 311 1686 384.1 958 1688 491.9 1,834

1690 601.6 2,928 1692 704.8 4.234 1693 (765) 4.969

1694 825.0 5,764 1696 948.7 7.538 1697 (1.006> 8,515

1698 1.063,3 9.550 1700 1,207.3 11.820 1702 1,320.0 14,347

1704 1,471.6 17,139 1706 1,612.2 20.223 1708 1,865.4 23,700

1710 2,186.4 27,752 1712 2,541.8 32,480 1714 2,913.9 37,936

1716 3.222,2 44,072 1718 3,479.1 50,774 1720 3,655.4 57,908

1725 4.396 78,037 1729.25 5.071 98.154 1730 5.190 102,002

1735 6,140 130.327 1740 6.965 163.089 1745 7,860 200,152

1750 8,980 242,252 1755 9.960 289,602 1760 11.435 343,089

1765 12,510 402,952 1770 13,885 468,939 1773 14,660 511757

47. REMARKS AND REFERENCES

Length at reservoir elevation 1729 from USGS quad maps of reservoir. North Fork Solomon River = 8.7 miles and Bow

Creek = 5.1 miles.

2

Average precipitation at Kirwin Dam. 1955-1996.

Calculated using mean annual runoff value of 34,338 AF, item 24.

Computed annual inflows from North Fork Solomon River and Bow Creek. 3/55 through 5/96 (by calendar year>.

Bureau of Reclamation Project Data Book, 1981.

6

Original surface area and capacity at elevation 1,729.25. top of water supply. Original capacity recomputed by

Reclamation's ACAP program using original surface areas.

Surface area and capacity at elevation 1729.25 computed.,, y ACAP program using 1996 and original surface areas.

1996 surveyed only underwater portion of reservoir belowelevation 1731.2. Due to heavy vegetation adequate data

collected at elevation 1720 and below. During the 1996 underwater survey reservoir was at elevation 17312.

Elevation 1725.0 and above from original measured areas.

Total capacity loss calculated by comparing original recomput ed capacity and 1996 capacity at reservoir elevation

1729.25, top of water supply elevation.

Maximum and minimum elevations and inflow values in acre-feet by calendar year, from 1955 through 5/96.

Capacities computed by ACAP computer program. Areas at eleva tion 1725 and above from origi nal survey.

48. AGENCY MAKING SURVEY Bureau of Reclamation

49. AGENCY SUPPLYING DATA Bureau of Reclamation DATE August 1997

Table 1. - Reservoir sediment data sunmiary (page 2 of 2).

13
Table 2 * Srary of 1996 survey results.

(1)

Elevation

(feet)

(2)

Original

Area

(acres)

(3)

Original

Capacity

(acre-feet)

(4)

1996

Area

(acres)

(5)

1996

Capacity

(acre-feet)

(6)

Measured

Sediment

Voltm

(acre-feet)

(7)

Percent

Measured

Sediment

(8)

Percent

Reservoir

Depth

1773.0 14.660 513.035 14.660 511,757 - - 100.0

1770.0 13.885 470.218 13.885 468,939 - - 97.3

1765.0 12.510 404.230 12.510 402,952 - 92.9

1760.0 11.435 344.368 11.435 343.089

____________

- - 88.5

1757.3 10.639 314.568 10.639 313.290 - - 86.1

1755.0 9.960 290,880 9.960 289.602 - - 84.1

1750.0 8.980 243.530 8.980 242.252 - - 79.6

1745.0 7,860 201.430 7860 200.152 - - 75.2

1740.0 6,965 164,368 6,965 163.089 - - 70.8

1735.0 6,140 131,605 6.140 130.327 - - 66.4

1730.0 5.190 103.280 5.190 102.002 - 61.9

1729.25 5.071 99.432 5,071 98.154 1.278 100.0 61.3

1725,0 4.396 79.315 4.396 78.037 1.278 100.0 61.3

1720,0 3,757 58.933 3.655 57.908 1.025 8&2 53.1

1715.0 2.974 42.105 3.068 40.927 1.178 92.2 48.7

1710.0 2.071 29,493 2,186 27.752 1.741 136.2

1705.0 1.585 20.353 1.542 18.646 1.707 133.6

__________

39.8

1700.0 1.273 13,208 1.207 11.820 1.388 108.6 35.4

1695.0 834 7.940 887 6.620 1.320 103.3 31.0

1693.0 720 6,386 765 4.969 1.417 110.9 29.2

1690.0 549 4,483 602 2.928 1.555 121.7 26.5

1685.0 371 2.183 323 604 1.579 123.6 22.1

1680.0 200 755 0 0 755 59.1 17.7

1675.0 39 158 0 0 158 12.4 13.3

1670.0 7 43 0 0 43 3.4 8.8

1665.0 5 13 0 0 13 1.0 4.4

1660.0 0 0 0 0 0 0.0 0.0

(1) Elevation of reservoir water surface.

(2) Original reservoir surface area.

(3) Original calculated reservoir capacity cquted using WAP fran original measured surface areas.

(4) Reservoir surface area fr 1996 survey for elevations 1720 and below. Areas for elevation 1725

and greater are original measured areas.

(5) 1996 calculated reservoir capacity ceuted using ACAP. from 1996 surface areas.

(6) Measured sediment volte = coltm (3) - colime (5).

(7) Measured sediment expressed in percentage of total sediment 1.278 acre-feet at elevation 1729.25.

(8) Depth of reservoir expressed in percentage of total depth (113 feet).

Note: The 1996 survey developed dated imderwater reservoir topography from elevation 1720.0

and below. Surface areas at elevation 1725 and above are original measured areas. Reservoir

elevation was at 1731.2 during 1996 xiderwater survey.

14

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15
Space intentionally left blank due to security concerns 
Kirwin Reservoir

1740

1735

1730

1725

1720

U-

-ri

1715

Ui

1710

1705

1700

1695

TOP OF CONSERVATION = 1729.25

TOP OF INACTIVE = 1697.0

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PLU5' AEVED DATA POINTS

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19
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Area-Capacity Curves for Kirwin Reservoir

Area (acres)

15000 13500 12000 10500 9000 7500 6000 4500 3000 1500 0

N.)

1 (L)

1770

1760

1750

1740

0

1730

. 1720

Ui

1710

1700

1690

1680

1670

1660

Capacity

1780

1770

1760

1750

1740

1730

1720

1710

1700

1690

1680

1670

1660

0 55500 111000 166500 222000 277500 333000 388500 444000 499500 555000

Capacity (acre-feet)
RECLAMATION'S MISSION

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.