Caballo Reservoir 

2007 Sedimentation Survey 

U.S. Department of the Interior 

Bureau of Reclamation 

Technical Service Center 

Denver, Colorado May 2008 
U.S. Department of the Interior 

Bureau of Reclamation 

Technical Service Center 

Water and Environmental Resources Division 

Sedimentation and River Hydraulics Group 

Denver, Colorado May 2008 

Caballo Reservoir 

2007 Sedimentation Survey 

prepared by 

Ronald L. Ferrari 
ACKNOWLEDGMENTS

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

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

this report. Ronald Ferrari and Mike Sixta of the Sedimentation Group conducted the 

hydrographic survey of the reservoir in September of 2007. Ron Ferrari completed the 

data processing to generate the new area-capacity tables. 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.
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PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 

1. REPORT DATE (DD-MM-YYYY) 

 May 2008 

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

5a. CONTRACT NUMBER 

5b. GRANT NUMBER 

4. TITLE AND SUBTITLE 

Caballo Reservoir 

2007 Sedimentation Survey 

5c. PROGRAM ELEMENT NUMBER 

5d. PROJECT NUMBER 

5e. TASK NUMBER 

6. AUTHOR(S) 

Ronald L. Ferrari 

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) 10. SPONSOR/MONITOR'S ACRONYM(S) 

Bureau of Reclamation, Denver Federal Center, PO Box 25007 

Denver, CO 80225-0007 11. SPONSOR/MONITOR'S REPORT 

NUMBER(S) 

12. DISTRIBUTION/AVAILABILITY STATEMENT 

13. SUPPLEMENTARY NOTES 

14. ABSTRACT 

The Bureau of Reclamation (Reclamation) surveyed Caballo Reservoir in September 2007 to compute a present storageelevation relationship (area-capacity tables). The underwater survey was conducted at the project’s reservoir elevation 4,135.0 

feet. The project datum is 43.3 feet lower than National Geodetic Vertical Datum of 1929 (NGVD29) and 45.5 feet lower than 

North American Vertical Datum of 1988 (NAVD88). The underwater survey used sonic depth recording equipment interfaced 

with 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 standard land 

surveying methods, using RTK GPS to measure portions of the 32 sedimentation range lines surveyed. 

As of September 2007, at reservoir water surface elevation 4,182.0 feet, the surface area was 11,532 acres with a total capacity 

of 324,934 acre-feet. Since the reservoir’s 1938 initial filling, 21,802 acre-feet of sediment have accumulated in Caballo 

Reservoir. Since the 1999 reservoir survey, 1,738 acre-feet of sediment have been trapped. The average annual rate of sediment 

accumulation since 1938 is 312.8 acre-feet and since 1999 it is 206.9 acre-feet. 

15. SUBJECT TERMS 

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

area/ RTK GPS 

16. SECURITY CLASSIFICATION OF: 19a. NAME OF RESPONSIBLE PERSON 

a. REPORT b. ABSTRACT a. THIS PAGE 

17. LIMITATION 

OF ABSTRACT

18. NUMBER 

OF PAGES 

19b. TELEPHONE NUMBER (Include area code)

Standard Form 298 (Rev. 8/98) 

Prescribed by ANSI Std. Z39.18 
Table of Contents 

Page 

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

Dam and Reservoir.................................................................................................................... 1 

Summary and Conclusions............................................................................................................... 2 

Control Survey Data Information..................................................................................................... 3 

Reservoir Operations........................................................................................................................ 4 

Hydrographic Survey Equipment and Method................................................................................. 4 

Reservoir Sediment Distribution ...................................................................................................... 9 

Lateral Distribution ................................................................................................................... 9 

Longitudinal Distribution.......................................................................................................... 9 

Development of the 2007 Caballo Reservoir Surface Areas................................................... 29 

Width adjustment method ................................................................................................ 29 

2007 Storage Capacity ............................................................................................................ 34 

2007 Reservoir Sediment Analyses................................................................................................ 37 

References...................................................................................................................................... 37 

Index of Figures 

Page 

 

Figure 1 - Bureau of Reclamation reservoirs in New Mexico.......................................................... 1 

Figure 2 - Survey vessel with mounted instrumentation on Jackson Lake in Wyoming.................. 5

Figure 3 - Caballo Reservoir sedimentation range lines................................................................... 7 

Figure 4 - Caballo Reservoir sedimentation range lines................................................................... 8 

Figure 5 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 1. ...................... 11 

Figure 6 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 2. ...................... 11 

Figure 7 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 3. ...................... 12 

Figure 8 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 4. ...................... 12 

Figure 9 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 5. ...................... 13 

Figure 10 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 6. .................... 13 

Figure 11 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 7. .................... 14 

Figure 12 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 8. .................... 14 

Figure 13 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 9. .................... 15 

Figure 14 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 10. .................. 15 

Figure 15 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 11. .................. 16 

Figure 16 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 12. .................. 16 

Figure 17 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 13. .................. 17 

Figure 18 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 14. .................. 17 

Figure 19 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 15. .................. 18 

Figure 20 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 16. .................. 18 

Figure 21 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 17. .................. 19 

Figure 22 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 18. .................. 19 

Figure 23 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 19. .................. 20 

Figure 24 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 20. .................. 20 

Figure 25 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 21. .................. 21 

Figure 26 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 22. .................. 21 

Figure 27 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 23. .................. 22 

Figure 28 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 24. .................. 22 

Figure 29 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 25. .................. 23 
Figure 30 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 26. .................. 23 

Figure 31 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 27. .................. 24 

Figure 32 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 28. .................. 24 

Figure 33 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 29. .................. 25 

Figure 34 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 30. .................. 25 

Figure 35 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 30A. ............... 26 

Figure 36 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 31. .................. 26 

Figure 37 - Altus Reservoir longitudinal profile. ........................................................................... 27 

Figure 38 - Width adjustment method for revising contour areas. ................................................. 30 

Figure 39 - Caballo Reservoir area and capacity plots. .................................................................. 33 

Index of Tables 

Page 

Table 1 - Reservoir sediment data summary (page 1 of 2)............................................................. 31 

Table 2 - Summary of 2007 survey results..................................................................................... 35 
Caballo Reservoir 

2007 Sedimentation Survey 

Introduction 

Dam and Reservoir 

Caballo Dam and Reservoir are located on the Rio Grande, 25 miles downstream 

of Elephant Butte Dam and 17 miles south of the city of Truth or Consequences in 

Sierra County of south central New Mexico (figure 1). Caballo Reservoir is a 

multi-use reservoir with its main function being water storage for irrigation and 

flood control. Caballo Reservoir is one of the two storage facilities of the Rio 

Grande Project that provides water for irrigation, municipal, and industrial use. 

Storage lost in Elephant Butte Reservoir due to sediment deposition is partially 

recovered by Caballo Reservoir storage. Recreation activities provided by 

Caballo Reservoir include year-round camping, boating, and fishing. 

Truth or Consequences

Figure 1 - Bureau of Reclamation reservoirs in New Mexico.

1
Construction of Caballo Dam began in 1936 and was completed in 1938 with first 

storage beginning in January of 1938. The dam is an earthfill zoned structure 

whose dimensions are: 

 Hydraulic height1 78 feet Structural height 96 feet 

 Crest length 4,558 feet Crest elevation 4,190.0 feet2

 Top width 35 feet Top of parapet wall 4,193.0 feet 

 

The spillway is a concrete-lined open channel in the left abutment controlled by 

dual 50-foot-wide by 22.5-foot-high radial gates with top of gate (including the 

1.5 foot splash plate) at elevation 4,183.5. The spillway has a crest elevation of 

4,161.0 and a maximum discharge capacity of 33,200 cubic feet per second (cfs) 

at reservoir elevation 4,182.0. 

The outlet works, located in the left abutment, consist of an intake with 

trashracks, 13.5 foot diameter concrete-lined upstream tunnel, a gated chamber 

with four 6-foot-wide by 7.5-foot-high pressure slide gates, a 13.5 foot diameter 

concrete lined downstream tunnel that is horseshoe shaped, and a concrete stilling 

basin. The outlet works were designed to pass 5,000 cfs at reservoir elevation 

4,182.0. 

The total drainage area of the Rio Grande above Caballo Dam is 27,260 square 

miles of which 1,237 square miles contribute sediment. The majority of the 

sediment inflow is trapped behind Elephant Butte Dam, but several tributaries 

flow into Caballo Reservoir, contributing sediment. At elevation 4,182.0, the 

reservoir length is around 16.7 miles with an average width of 1.1 miles. 

Summary and Conclusions 

This Reclamation report presents the results of the 2007 survey of Caballo 

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

$ compute area-capacity relationships 

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

The bathymetric survey was run using sonic depth recording equipment interfaced 

with a differential global positioning system capable of determining sounding 

 

1 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.

2

 Elevations in feet. All elevations based on the original project datum established by U.S. Bureau of 

Reclamation that is around 43.3 feet lower than NGVD29 and 45.5 feet lower than NAVD88. 

2
locations within the reservoir. The system continuously recorded depth and 

horizontal coordinates of the survey boat as it navigated along previously 

established sediment range 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 

on the project’s datum. 

Standard land surveying techniques were used to measure the upper reservoir 

sediment range lines that could not be covered during the bathymetric survey. 

Land portions of range lines 10 through 31 were surveyed in September 2007. 

The land survey techniques were used to measure any noted changes on these 

range lines. The results from these surveys were used to develop the 2007 area 

and capacity tables and to compute the volume of sediment that has accumulated 

since the previous surveys. 

Tables 1 and 2 contain the summary of the 2007 Caballo Reservoir survey results. 

The 2007 survey determined that the reservoir has a total storage capacity of 

324,934 acre-feet and a surface area of 11,532 acres at reservoir elevation 

4,182.0. The 2007 area and capacity tables were produced by a computer 

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

compute the area and capacity at prescribed elevation increments (Bureau of 

Reclamation, 1985). The volume of sediments that have accumulated in the 

reservoir since the original (1938) survey is 21,802 acre-feet representing a total 

loss in reservoir capacity of 6.3 percent. The average annual sediment 

accumulation rate for the 69.7 years of record is 312.8 acre-feet. 

Control Survey Data Information 

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 surveys. OPUS is operated by the National 

Geodetic Survey (NGS) and allows users to submit GPS data files where it is 

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

control network. Initially, the GPS base was set over a temporarily driven piece 

of rebar on the west bank overlooking the reservoir. The coordinates for this 

point were processed using OPUS, and from this base additional points were 

established and checked during the survey using OPUS. The OPUS generated 

coordinates were further verified by RTK GPS observation shots on the NGS 

datum point “C 366,” located downstream of Caballo Dam. 

The horizontal control was established in New Mexico state plane coordinates, 

central zone, on the North American Datum of 1983 (NAD83). The vertical 

control for the established points was on the National American Vertical Datum 

3
of 1988 (NAVD88). RTK GPS water surface measurements were periodically 

collected and a comparison of the reservoir water surface recorded by the 

Reclamation gage found they were around 45.5 feet higher. NGS published data 

in the study area shows the NAVD88 elevations are around 2.2 feet higher than 

NGVD29 elevations. These values compare well with the previous studies that 

noted a 43.3 feet difference between the NGVD29 datum and the Reclamation 

project datum. 

Reservoir Operations 

Caballo Reservoir is part of the Rio Grand Project that provides storage for 

irrigation, flood control, and recreation. The September 2007 capacity table lists 

324,934 acre-feet of total storage below water surface elevation 4,182.0, table 1. 

The 2007 survey measured a minimum lake bottom elevation of 4,120.0. The 

reservoir was designed to provide a minimum of 100,000 acre feet of storage 

capacity for flood control purposes (Bureau of Reclamation, 2005). The capacity 

values from elevation 4,182.0 and below are from the 2007 results. 

 $ 47,000 acre-feet of surcharge between elevation 4,182.0 and 4,186.0. 

 $ 100,046 acre-feet of flood control between elevation 4,172.44 and 4,182.0. 

 $ 224,888 acre-foot of conservation between elevation 4,104.0 and 4,172.44. 

 $ 0 acre-foot of dead storage below 4,104.0. 

Caballo Reservoir computed annual inflow and reservoir stage records are listed 

by water year on table 1 for the period of 1938 through 2007. The inflow values 

computed by the Upper Colorado Region show the annual fluctuation with a 

computed average inflow of 680,900 acre-feet through September of 2007. The 

maximum reservoir elevation was 4,182.1 recorded during water year 1942. 

Since the last survey in 1999, the maximum recorded reservoir elevation was 

4,159.6 recorded during water year 2000 with the minimum recorded elevation 

4,126.8 during water years 2001 and 2003. 

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 2. 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 

4
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 2 - 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 

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

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

Mexico’s state plane coordinates, central zone in NAD83. The RTK GPS system 

employs two receivers that track the same satellites simultaneously just like with 

differential GPS. 

The Caballo Reservoir bathymetric survey was conducted on September 22, 2007 

at water surface elevation 4,135.0 (Reclamation project datum). The boat was 

used again on September 26 of 2007 to collect additional data between the 

sediment range lines that could be used for more detailed mapping of the 

reservoir. However, with the reservoir nearly twelve feet lower than the 1999 

survey; this portion of the reservoir was relatively small compared to the overall 

reservoir and assumed insignificant to this sediment analysis. That data has been 

preserved for future analyses if needed. 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 the range lines. The survey vessel's guidance system provided 

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

predetermined lines. A layout of the reservoir sedimentation range line system is 

shown on figures 3 and 4. During each range line traverse, the depth and position 

data were recorded on the notebook computer hard drive for subsequent 

processing. The water surface elevation at the dam, recorded by a Reclamation 

5
gage, was used to convert the sonic depth measurements to lake-bottom 

elevations. The elevations are all tied to Reclamation’s project datum that is 43.3 

feet lower than NGVD29 and 45.5 feet lower than NAVD88. 

The 2007 underwater data was collected by a depth sounder that was calibrated by 

adjusting the speed of sound through the water column which can vary with 

density, salinity, temperature, turbidity, and other conditions. The collected 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. Additional information on 

collection and analysis procedures are outlined in Chapter 9 of the Erosion and 

Sedimentation Manual (Ferrari and Collins, 2006). 

The upper portion of the reservoir not covered by the 2007 large boat survey, 

sediment range lines 10 through 31, were also surveyed in September of 2007. 

Standard land surveying techniques were used to measure only the portions of 

these range lines that indicated possible change. Spot check measurements were 

conducted on other portions of the range lines to confirm there were no significant 

changes since the previous surveys. Access to portions of some of the range lines 

was hindered by soft bottom sediments, but these deposits were fairly flat and the 

sediment elevation was easily projected along the remainder of the range line 

alignment. The above water data was tied to the same control network as the 

bathymetric collection with the elevations in NAVD88. During post processing, 

the elevations were shifted to match the Reclamation vertical datum that is 45.5 

feet lower than NAVD88. 

6
7
8
Reservoir Sediment Distribution 

Lateral Distribution 

Ground profiles of the 32 reservoir sedimentation ranges are plotted on figures 5 

through 36 where the profiles illustrate the general lateral distribution of 

sediments in the reservoir. The plots illustrate the survey results from the 1938 

(original), 1981, 1999, and 2007 surveys. During the 1981 survey, the abovewater portions of each range line from each end point to the water edge were 

measured. For the main portion of the reservoir, range lines 1 through 10, the 

results from the 1981 and 1999 surveys were used to develop the range line plots 

for the areas not covered by the 2007 underwater survey. The 1981 and 1999 data 

were also used to complete the plots of the remaining range lines (11 through 31) 

in areas that the 2007 field crew and collected data determined there was no 

significant change and for portions that were not accessible. 

Longitudinal Distribution 

To illustrate the sediment distribution throughout the reservoir a longitudinal 

profile was plotted for the 1938, 1981, 1999, and 2007 reservoir conditions 

(figure 37). The differences between the profiles represent the sediment 

encroachment into the reservoir since the dam closed in 1938. The average 

bottom elevations for each range line were used to plot these longitudinal profiles. 

As with the lateral plots, the longitudinal plots illustrate minimal change since the 

1999 survey. The plots show sediment deposits below range line 23 with the 

greatest depths of longitudinal sediment deposits occurring downstream of range 

line 17 for all the surveys. This pattern of sediment deposition is due to reservoir 

operation as the water surface is usually drawn down below elevation 4,140. 

Over time it is expected the pivot point near elevation 4,142 will begin to move 

further downstream, but the 1999 to 2007 survey results measured only minimal 

movement. Even though Elephant Butte Reservoir traps the majority of the 

sediment originating upstream, there are several tributaries into Caballo Reservoir 

contributing sediment during high flow events that deposits within the reservoir. 

9
This Page Intentionally Left Blank.

10
Caballo Sedimentation Range Profiles: Range Line 1

1938, 1981, 1999, and 2007 Surveys

4100

4120

4140

4160

4180

4200

4220

0 500 1000 1500 2000 2500 3000 3500 4000

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 5 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 1. 

Caballo Sedimentation Range Profiles: Range Line 2

1938, 1981, 1999, and 2007 Surveys

4100

4120

4140

4160

4180

4200

4220

4240

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 6 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 2. 

11
Caballo Sedimentation Range Profiles: Range Line 3

1938, 1981, 1999, and 2007 Surveys

4100

4120

4140

4160

4180

4200

4220

4240

0 500 1000 1500 2000 2500 3000 3500 4000

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 7 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 3. 

Caballo Sedimentation Range Profiles: Range Line 4

1938, 1981, 1999, and 2007 Surveys

4100

4120

4140

4160

4180

4200

4220

4240

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 8 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 4. 

12
Caballo Sedimentation Range Profiles: Range Line 5

1938, 1981, 1999, and 2007 Surveys

4100

4120

4140

4160

4180

4200

4220

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 9 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 5. 

Caballo Sedimentation Range Profiles: Range Line 6

1938, 1981, 1999, and 2007 Surveys

4100

4120

4140

4160

4180

4200

4220

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 10 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 6. 

13
Caballo Sedimentation Range Profiles: Range Line 7

1938, 1981, 1999, and 2007 Surveys

4100

4120

4140

4160

4180

4200

4220

4240

0 1000 2000 3000 4000 5000 6000 7000 8000 9000

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 11 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 7. 

Caballo Sedimentation Range Profiles: Range Line 8

1938, 1981, 1999, and 2007 Surveys

4100

4120

4140

4160

4180

4200

4220

0 1000 2000 3000 4000 5000 6000 7000 8000 9000

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 12 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 8. 

14
Caballo Sedimentation Range Profiles: Range Line 9

1938, 1981, 1999, and 2007 Surveys

4110

4120

4130

4140

4150

4160

4170

4180

4190

4200

4210

4220

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 13 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 9. 

Caballo Sedimentation Range Profiles: Range Line 10

1938, 1981, 1999, and 2007 Surveys

4110

4120

4130

4140

4150

4160

4170

4180

4190

4200

4210

4220

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 14 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 10. 

15
Caballo Sedimentation Range Profiles: Range Line 11

1938, 1981, 1999, and 2007 Surveys

4120

4140

4160

4180

4200

4220

4240

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 15 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 11. 

Caballo Sedimentation Range Profiles: Range Line 12

1938, 1981, 1999, and 2007 Surveys

4120

4140

4160

4180

4200

4220

4240

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 16 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 12.

16
Caballo Sedimentation Range Profiles: Range Line 13

1938, 1981, 1999, and 2007 Surveys

4120

4140

4160

4180

4200

4220

4240

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 17 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 13. 

Caballo Sedimentation Range Profiles: Range Line 14

1938, 1981, 1999, and 2007 Surveys

4120

4140

4160

4180

4200

4220

4240

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 18 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 14. 

17
Caballo Sedimentation Range Profiles: Range Line 15

1938, 1981, 1999, and 2007 Surveys

4120

4140

4160

4180

4200

4220

4240

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 19 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 15. 

Caballo Sedimentation Range Profiles: Range Line 16

1938, 1981, 1999, and 2007 Surveys

4130

4140

4150

4160

4170

4180

4190

4200

4210

4220

4230

4240

0 500 1000 1500 2000 2500 3000 3500

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 20 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 16. 

18
Caballo Sedimentation Range Profiles: Range Line 17

1938, 1981, 1999, and 2007 Surveys

4130

4140

4150

4160

4170

4180

4190

4200

4210

4220

4230

4240

4250

4260

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 21 – Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 17. 

Caballo Sedimentation Range Profiles: Range Line 18

1938, 1981, 1999, and 2007 Surveys

4130

4150

4170

4190

4210

4230

4250

4270

4290

4310

4330

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 22 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 18. 

19
Caballo Sedimentation Range Profiles: Range Line 19

1938, 1981, 1999, and 2007 Surveys

4130

4140

4150

4160

4170

4180

4190

4200

4210

4220

4230

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000 8500

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 23 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 19. 

Caballo Sedimentation Range Profiles: Range Line 20

1938, 1981, 1999, and 2007 Surveys

4130

4140

4150

4160

4170

4180

4190

4200

4210

4220

4230

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000 8500 9000 9500

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 24 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 20. 

20
Caballo Sedimentation Range Profiles: Range Line 21

1938, 1981, 1999, and 2007 Surveys

4140

4150

4160

4170

4180

4190

4200

4210

4220

4230

4240

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000 8500 9000 9500

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 25 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 21. 

Caballo Sedimentation Range Profiles: Range Line 22

1938, 1981, 1999, and 2007 Surveys

4140

4150

4160

4170

4180

4190

4200

4210

4220

4230

4240

0 1000 2000 3000 4000 5000 6000 7000 8000 9000

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 26 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 22. 

21
Caballo Sedimentation Range Profiles: Range Line 23

1938, 1981, 1999, and 2007 Surveys

4140

4150

4160

4170

4180

4190

4200

4210

4220

4230

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 27 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 23. 

Caballo Sedimentation Range Profiles: Range Line 24

1938, 1981, 1999, and 2007 Surveys

4150

4160

4170

4180

4190

4200

4210

4220

4230

0 500 1000 1500 2000 2500 3000 3500 4000 4500

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 28 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 24. 

22
Caballo Sedimentation Range Profiles: Range Line 25

1938, 1981, 1999, and 2007 Surveys

4150

4160

4170

4180

4190

4200

4210

4220

4230

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 29 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 25. 

Caballo Sedimentation Range Profiles: Range Line 26

1938, 1981, 1999, and 2007 Surveys

4150

4160

4170

4180

4190

4200

4210

4220

4230

4240

4250

0 200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 30 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 26. 

23
Caballo Sedimentation Range Profiles: Range Line 27

1938, 1981, 1999, and 2007 Surveys

4150

4160

4170

4180

4190

4200

4210

4220

4230

4240

4250

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 31 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 27. 

Caballo Sedimentation Range Profiles: Range Line 28

1938, 1981, 1999, and 2007 Surveys

4150

4160

4170

4180

4190

4200

4210

4220

4230

4240

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 32 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 28. 

24
Caballo Sedimentation Range Profiles: Range Line 29

1938, 1981, 1999, and 2007 Surveys

4160

4170

4180

4190

4200

4210

4220

4230

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000 8500

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 33 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 29. 

Caballo Sedimentation Range Profiles: Range Line 30

1938, 1981, 1999, and 2007 Surveys

4160

4170

4180

4190

4200

4210

4220

4230

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000 8500

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 34 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 30. 

25
Caballo Sedimentation Range Profiles: Range Line 30A

1938, 1981, 1999, and 2007 Surveys

4165

4170

4175

4180

4185

4190

4195

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500 7000 7500 8000 8500

Distance (ft)

Elevation (ft)

1938 Survey

1981 Survey

1999 Survey

2007 Survey

Figure 35 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 30A. 

Caballo Sedimentation Range Profiles: Range Line 31

1938, 1981, and 1999 Surveys

4160

4170

4180

4190

4200

4210

4220

4230

4240

-500 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 5500 6000 6500

Distance (ft)

Elevation (ft)

1938 Original Survey

1981 Survey

1999 Survey

Figure 36 - Sedimentation range profiles for 1938, 1981, 1999, and 2007 - range 31. 

26
Caballo Reservoir Longitudinal Average Bed P

1938, 1981, 1999, 2007 Comparison

411041154120412541304135414041454150415541604165417041754180

354045505560657075808590 

Channel Distance Upstream of Dam (thousan

Elevation (ft)

RL 20

RL 2

RL 3

5

0

RL 31 

RL 16

RL 17

RL 19

RL 18

RL 24

RL 23

RL 22

RL 21

RL 29

RL 28

RL 27

RL 26

RL 30A

27
This Page Intentionally Left Blank 

28
Development of the 2007 Caballo Reservoir Surface 

Areas 

Width adjustment method 

In some previous Caballo Reservoir resurveys, new contour maps were drawn 

from the range-line survey data. Contours between collected range-lines for new 

maps were drawn using the original contour map as a guide or control and 

estimating the new contour location based on changes that occurred at each rangeline. This method was eventually abandoned for the constant factor method, 

which was further modified to the width adjustment method (Ferrari and Collins, 

2006). In the width adjustment method, illustrated on figure 38, the new contour 

area, A1, between any two ranges is computed by applying an adjustment factor to 

the original contour area, A0, between the two ranges. This adjustment factor is 

defined as the ratio of the new average width to the original average width for 

both upstream and downstream ranges at the specified contour. The revised 

segmented surface areas for each contour are then summed for the whole 

reservoir. The summarized segmented surface area versus elevation becomes the 

basic input for volume computations. 

A comparison of the simultaneous plots of original range profiles against the 

resurveyed range profiles indicates the lateral distribution of the sediment at the 

measured points. Where these plots indicate changes have occurred on the side 

slopes of the reservoir, an engineering judgment decision is required to determine 

whether the change is due to survey inaccuracies or due to actual deposition or 

erosion. 

On the original full scale base topography map of Caballo Reservoir, the finalized 

location of all reservoir sediment ranges were marked. This divided the reservoir 

into storage segments defined either by adjacent range lines and/or by terminal 

ends of the reservoir, such as the dam or upstream ends of surface area contours. 

For the 1981 sedimentation study, planimetering determined the original 

segmental contour surface areas between boundaries at a maximum water surface 

elevation of 4,182 and for each 5-foot contour from elevation 4,180 to the lowest 

original contour area within each segment. For the 1938 and 2007 measured 

range lines, the width of all contours for each segment was computed at 5-foot 

contour intervals. From these values, adjustment factors were computed by 

dividing the new survey average width by the original survey average width for 

each contour interval within each segment. The new segmental contour areas 

were computed by multiplying the original contour area by the adjustment factor. 

All segment areas, by elevation increments, were added together to develop the 

2007 surface areas used in the area-capacity computations. 

29
Initial Survey New Survey

Ao = Contour Area A1 = Contour Area (Computed) 

Wo' = Downstream Width W1′ = Downstream Width 

Wo′′ = Upstream Width W1′′ = Upstream Width 

( ) ( )⎥

⎦

⎤ ⎢

⎣

⎡

+

+ = "

0

'

0

"

1

'

1

1 WW

WW A

Figure 38 - Width adjustment method for revising contour areas. 

30
31

1. 2. 3. STATE New Mexico

4. 5. Truth or Consequences 6. COUNTY

7. ° 53 ' 0 5 " ° 17 ' 30 " 8. 1 9. SPILLWAY CREST EL 2

10. 11. 12. GROSS STORAGE 15

CAPACITY, AC-FT

a. 

b. 4

c. 3

d. 16

e.

f.

g.

17. LENGTH OF RESERVOIR

18. TOTAL DRAINAGE AREA 5 22. 4

19. NET SEDIMENT CONTRIBUTING AREA 5 23. MEAN ANNUAL RUNOFF 6

20. LENGTH MILES AVG. WIDTH MILES 24. MEAN ANNUAL INFLOW 7

21. 25. °F °F7

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

26. DATE OF 35. 36

8 8

9

26. DATE OF 37. 38.

8

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.

8

43.

c.

673

354.1

AVG. ANN.

PERCENT OF TOTAL SEDIMENT LOCATED WITHIN REACH DESIGNATION

15,226

0.0

PERCENT OF TOTAL SEDIMENT LOCATED WITHIN DEPTH DESIGNATION

4,105

4,115

9/30/2007

21,802

0.286

1/15/1981

4/14/1999

467 0.102

1/6/1938

a.

15,067,967

5,241,800

467 4.39

PERIOD a. AVG. ANNUAL

327.3

312.8 0.253

673

688,700

47,459,100

0.265

27,149,333

42,217,300

 /MI.2

-YR.

E 18.3 61.3

A 

69.7

A

0.286

105-

4,135

34.5

4,145

4,155

0.0

4,175

20,064

1/15/1981

OF 4,115 4,125

a.

0.167

0.214

4,125

26.

DATE

1/6/1938

4/14/1999

9/30/2007

1/6/1938

1/15/1981

4/14/1999

9/30/2007

SURVEY

RANGES OR 

YRS

PER. PER.

YRS

4/14/1999 11,532

Contour (D)

SURVEY

34. PERIOD

27.5

SURVEY

TYPE OF 

MIN. ELEVATION

NO. OF

a.

823,390

631,380

PRECIPITATION

MEAN ANN.

Range (D)

1/6/1938

ANNUAL

9/30/2007

Range (D)

 

Range (D)

32.7

LONG 107

SURCHARGE

STORAGE

ALLOCATION

ELEVATION

27260

624,000

6.5

8.6

0-10 10-20 20-30 30-40 60-70 70-80 110-

35.4

3.3 0.5

30.6

21.8 6.2

4,165 4,175

3.3 0.6

4,155

4,182 

3.8

0.090 6.29

0.094 5.79

4,165

4,135 4,145

19.9 0.9

27.7

20.0

3.5

30.2 4.0

50-60 90-100 115- 120-

75

40-50 80-90

0.0

DATE

9/30/07

SURVEY

26. 44.

6.0

1/15/81

4/14/99

REACH DESIGNATION PERCENT OF TOTAL ORIGINAL LENGTH OF RESERVOIR

DEPTH DESIGNATION ELEVATION RANGE IN FEET

4,838

1,738

264.4

206.9

15,226 354.1

INTERVALS

AREA, AC.

8

8

MAX. ANN.

11,532 9

8

11,532

TOP OF POOL

4 W

ACRE-FEET

INCHES

INCHES

MILES

8.71

680,900

0.47

TOP OF DAM ELEVATION

RANGE

Bureau of Reclamation STREAM

19

Rio Grande River

NEAREST P.O.

32

I MAX. ELEVATION

JOINT USE

CONSERVATION

S

A

B

16.7

45

SQUARE MILES

1237 SQUARE MILES

MILES

U

N 10000

S

4,182.0 11,532

R

V

MULTIPLE USE

AVG. WIDTH OF RESERVOIR 1.08

R

O

I INACTIVE

E FLOOD CONTROL

R

E

S

0

ORIGINAL

SURFACE AREA, AC-FT

13.

346,736

8.4

DEAD

0

346,736

4,104.0 0

 

326,672

346,736

324,934

331,510

64

MEAN ANNUAL PRECIPITATION

32.

ACRE - FEET

4100.5

0.48

BEGAN

DATE NORMAL

33.

OPERATIONS

2/8/38

111

1,693,000

b.

PERIOD WATER INFLOW, ACRE-FEET

813,100

1,930,000 27,149,333

c. TOTAL a. 

WATER INFLOW TO DATE, AF

MEAN ANN. b. TOTAL

 

AVG. ANN. /MI.2

-YR. TOTAL b.

631,380

680,900

TOTAL SEDIMENT DEPOSITS TO DATE, AF

a.

 

TOTAL b.

PERIOD CAPACITY LOSS, ACRE-FEET

c.

V

R

1/15/1981

SURVEY

SURVEY

ANNUAL TEMP, MEAN °F RANGE -16

43 43

Y

D

T

RESERVOIR SEDIMENT

DATA SUMMARY

Caballo Reservoir

NAME OF RESERVOIR 1

M

D

A 1 TWP. 6 S

OWNER

SEC

LAT

DATA SHEET NO.

32 (RL)

5-ft (CI) 11,532

32 (RL)

32 (RL)

4190.0

14.

4161.00

ACRE-FEET

ORIGINAL 

SURFACE

DATE

STORAGE

CAPACITY

to

BEGAN

1/6/38

Sierra

RATIO AF/AF

0.51

0.48

0.49

Table 1 - Reservoir sediment data summary (page 1 of 2). 
32

 

1

2

3

4

5

6

7

8

9

10

4,123.1 875,800

1945 4,178.1 4,120.6 843,200 1946 4,175.9 4,121.1 858,800

1943 4,181.1 4,119.2 807,000

714,300

1941 4,158.8 4,119.7 692,800 1942 4,182.1 4,133.7 1,930,000

1939 4,155.2 4,108.1 915,600 1940 4,154.2 4,123.9

1944 4,176.4

1952

1948

4,180.0

1950

4,119.2

4,131.8

4,121.9

720,800

4,165.6

4,175.2

4,153.4 543,000

4,125.2 742,800

4,132.5

451,100 4,120.0

707,900

754,600

1947

1949

1951

4,178.8

4,164.8

4,162.2

SURVEY 

4,180.0 11,104 324,100 4,182.0 11,532 346,736

1961

9,967 271,442

1938

1,305

4,158.4

ELEVATION AREA CAPACITY

4,152.9

4,158.1

4,148.9 4,134.0

4,162.0

1991

1995

SURVEY 4,110.0 71 187

1,554

3,880

7,103

3,617

4,160.0

4,145.0

4,175.0

2007

Annual inflow from 1938 through 2007, item 45.

Elevations tied to project datum that is 43.3 feet less than NGVD29 and 45.5 feet less than NAVD88. Top parapet wall, elevation 4,193.0.

4,175.0 9,967 11,104 324,934

47. REMARKS AND REFERENCES

Calculated using mean annual runoff value of 680,900 AF (item 24).

249,620 302,298 4,182.0 11,532

Spillway crest, El. 4,161.0. Top active conservation, El. 4,172.44. Top flood pool and radial gates, El. 4,182.0. Splash plate crest, El. 4,183.5.

49. Bureau of Reclamation April 2008

AGENCY MAKING SURVEY

AGENCY SUPPLYING DATA DATE

48.

10

4,115.0

4,130.0

4,145.0

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

Bureau of Reclamation

Exclusive flood pool is top 100,000 AF, El. 4,172.44 to El. 4,182.0. Below 4,172.44 is conservation storage for irrigation.

BOR Project Data Book, 1981. Annual precipitation at dam, 8.71 inches (1936-1992) from NOAA/NWS.

Removed drainage area above Elephant Butte Reservoir. 

Values from 1981 Sedimentation Survey report.

 February 1938 through 1998 from 1999 report. 1999 through October 1, 2007 computed by Reclamation regional office. 

 capacity values. 

Range lines 1 through 9 by bathymetric survey. Ranges line 10, combination of RTK GPS land and bathymetric survey. Range lines 11

 through 30 by RTK GPS land survey for portions of the lines accessible. Width adjustment method used to compute new area and 

738,600

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

1938 4,129.4 4,110.2

8,429

44,554

124,646

64,180

146,067

1953 4,122.0

4,120.2

1987 4,174.8 4,172.3

4,135.8

1971

4,172.6

4,155.9

4,133.8

4,164.4 245,400

1955 4,121.5 211,800 1956 4,121.3 253,600

553,700 4,138.6

4,121.7

4,131.2

1954 4,124.1

791,700

1959 4,133.1 699,500 1960 4,160.6 4,119.5 681,800

1957 384,400

578,600 1962 4,160.1

1958 4,159.1

4,129.2 691,500

1973 4,137.0 604,300 1974 4,155.2 4,132.0 672,900

4,123.7

661,900

1979 4,130.1 574,400 1980 4,160.9 4,130.3 670,300

1975 4,134.0

635,300 1982

646,500 1976 4,152.0 4,135.8

4,130.8 691,700

1985 4,172.9 4,135.9 901,000 1986 4,176.7 4,173.4

1981 4,129.1

666,100

1,693,000

1989 4,165.8 4,148.1 730,800

1988 4,178.5 4,152.2 685,300

1992 4,154.7 4,138.1

1990 4,150.1 4,135.6

705,800

1993 4,172.4 4,136.5 1,061,100 1994 4,178.5 4,143.9 711,100

573,100

4,137.9 698,200

1997 4,151.8 4,140.2 741,300

4,177.3 4,138.4 1,184,000 1996

4,146.5 4,131.3 668,200

1998

2006

2000

4,158.4 4,126.8 773,600 2002

4,150.9 4,134.0 461,800

4,132.7 570,900 

46. ELEVATION - AREA - CAPACITY - DATA FOR

86,100

4,105.0 0 0

 

4,794 65,581

7,737

4,120.0 983 4,702 4,125.0 1,576 11,100

4,140.0 2,657 28,869

113,315

224,545

2,271

46,540

4,155.0 5,913 92,348

CAPACITY ELEVATION AREA CAPACITY

4,150.0

4,135.0 1,982 17,270

45. RANGE IN RESERVOIR OPERATION

1965 4,144.2 4,125.5

4,151.3 4,139.1

ELEVATION

376

2005

1999 736,200

AREA

2007 4,151.9

4,149.0 4,122.2 516,500 1972

1969 4,150.5 4,137.6 667,000 1970 4,150.7 685,600

300,200

1963 4,154.2 4,134.7 509,900 1964 4,138.2 4,122.3 183,400

4,132.7

1966 4,162.0 4,128.3

4,143.8 4,124.6

660,900

1967 4,155.0 4,133.7 433,100 1968 4,162.6 4,134.9 548,500

520,900

4,150.0 4,888 4,155.0 5,998

4,165.0 7,752 183,205 4,170.0 8,784

4,115.0 0 0 4,120.0 0 0 4,125.0 909

4,130.0 2,129 20,362 4,135.0 2,583 32,142 4,140.0 3,176

1977 4,160.0 4,126.3 395,900 1978 4,145.0 4,127.6 375,400

4,159.6 4,138.9 751,900

4,150.3 4,141.2 825,900

1,101,000

4,155.1

4,171.4

4,138.1 813,100

2003 4,150.1 4,126.8 338,300 2004 4,151.7 4,131.6

2001

411,700

1983 4,160.9 4,139.7 662,500 1984 4,158.9 4,130.2 650,300

4,154.4

4,160.0 7,006 4,165.0 161,504 4,170.0 8,771 202,775

Table 1 – Reservoir sediment data summary (page 2 of 2). 
33

Area-Capacity Curves for Caballo Reservoir

4,1004,1054,1104,1154,1204,1254,1304,1354,1404,1454,1504,1554,1604,1654,1704,1754,1804,185

0 35000 70000 105000 140000 175000 210000 245000 280000 

Capacity (acre-feet)

Elevation (feet)

12,000 10,800 9,600 8,400 7,200 6,000 4,800 3,600 2,400 

Area (acres)

200719991981Original

Capacity

Area

Figure 39 - Caballo Reservoir area and capacity plots. 
2007 Storage Capacity 

The storage-elevation relationships for Caballo Reservoir, based on the measured 

surface areas, were generated in the area-capacity program ACAP using the least 

squares method of curve fitting (Bureau of Reclamation, 1985). This program 

computes the surface area at 1.0-, 0.1-, and 0.01-foot increments by linear 

interpolation between basic data contours. The respective capacities and capacity 

equations are than obtained by integration of the area equations. The initial 

capacity equation is tested over successive intervals to check whether it fits within 

an allowable error term (set at 0.000001 for Caballo 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. Differentiating 

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

capacity 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 Caballo Reservoir area and capacity computations are listed in a 

separate set of 2007 area and capacity tables and have been published for the 0.01, 

0.1 and 1-foot elevation increments (Bureau of Reclamation, 2007). A 

description of the computations and coefficients output from the ACAP program 

is included with these tables. The 1938, 1981, 1999 and 2007 area-capacity 

relationships are listed on table 2 and the curves are plotted on figure 39. As of 

September 2007, at reservoir water surface elevation 4,182.0, the surface area was 

11,532 acres with a total capacity of 324,934 acre-feet. 

34
1 2 3 4 5 6 7 8 910 11 

1938 1938 1981 1981 1999 199

 Original Original 1981 1981 Sediment Percent 1999 1999 Sediment Perc

Elevation Area Capacity Area Capacity Volume Computed Area Capacity Volume Compu

Feet Acres Ac-Ft Acres Ac-Ft Ac-Ft Sediment Acres Ac-Ft Ac-Ft Sedim

4,182 11,532 346,736 11,532 331,510 15,226 100.0 11,532 326,672 20,064 4,180 11,104 324,100 11,104 308,874 15,226 100.0 11,104 304,035 20,065 4,175 9,967 271,422 9,967 256,196 15,226 100.0 9,967 251,358 20,064 4,170 8,784 224,545 8,767 209,361 15,184 99.7 8,767 204,523 20,022 4,165 7,752 183,205 7,730 168,119 15,086 99.1 7,741 163,255 19,950 4,160 7,103 146,067 7,032 131,214 14,853 97.6 7,031 126,325 19,742 4,155 5,998 113,315 5,930 98,809 14,506 95.3 5,889 94,027 19,288 4,150 4,888 86,100 4,874 71,799 14,301 93.9 4,854 67,170 18,930 4,145 3,880 64,180 3,766 50,199 13,981 91.8 3,733 45,700 18,480 4,140 3,176 46,540 2,804 33,774 12,766 83.8 2,719 29,569 16,971 4,135 2,583 32,142 2,226 21,199 10,943 71.9 2,038 17,677 14,465 4,130 2,129 20,362 1,580 11,684 8,678 57.0 1,546 8,718 11,644 4,125 1,576 11,100 1,168 4,814 6,286 41.3 861 2,701 8,399 

4,120 983 4,702 505 631 4,071 26.7 110 274 4,428 

4,115 376 1,305 0 0 1,305 8.6 0 0 1,305 

4,110 71 187 0 0 187 1.2 0 0 187 

4,105 4 0 0 0 00.0 0 0 0

4,100 0 0 0 0 00.0 0 0 0

1 Reservoir water surface elevation. Elevations tied to project datum that is 43.3 feet less than NGVD29 and 45.5 feet 2 Original, 1938 reservoir surface area.3 Original, 1938 reservoir capacity.4 1981 reservoir surface area.5 1981 reservoir capacity.6 1981 computed sediment volume, column (3) - column (5).7 1981 measured sediment in percentage of total sediment of 15,226 acre-feet.8 1999 reservoir surface area.9 1999 reservoir capacity.

10 1999 computed sediment volume, column (3) - column (9).11 1999 measured sediment in percentage of total sediment of 20,064 acre-feet.12 2007 measured reservoir surface area.13 2007 reservoir capacity computed using ACAP.14 2007 measured sediment volume, column (3) - column (13).15 2007 measured sediment in percentage of total sediment of 21,802 acre-feet.16 Depth of reservoir expressed in percentage of total depth, 82 feet, from maximum water surface 4,182.0.

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2007 Reservoir Sediment Analyses 

The Caballo Reservoir 1938 (original), 1981, 1999, and 2007 area and capacity 

values are illustrated on figures 39 and the results are listed on tables 1 and 2. 

These presentations illustrate the capacity loss that has occurred during the 69.7 

years of reservoir operations. This study found that as of September 2007, at 

reservoir water surface elevation 4,182.0, the surface area was 11,532 acres with a 

total capacity of 324,934 acre-feet. Since the reservoir’s initial filling in 1938, 

21,802 acre-feet of sediment have accumulated in Caballo Reservoir. Since the 

1999 reservoir survey, 1,738 acre-feet of sediment have been trapped. The 

average annual rate of sediment accumulation since 1938 is 312.8 acre-feet and 

since 1999 it is 206.9 acre-feet. 

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, December 2005. Standing Operating Procedures (SOP), 

Caballo Reservoir, Rio Grande Project, New Mexico - Texas, Upper Colorado 

Region, Albuquerque, New Mexico. 

Bureau of Reclamation, September 2007. Caballo Reservoir Area and Capacity 

Tables, Rio Grande Project, Upper Colorado Region, Albuquerque, New Mexico. 

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

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