Any use of trade, product or firm names is for descriptive purposes only and

does not imply endorsement by the U.S. Government.

Although these data have been processed successfully on a computer system

at the U.S. Geological Survey, no warranty expressed or implied is made

regarding the display or utility of the data on any other system, or for general

or scientific purposes, nor shall the act of distribution constitute any such

warranty. The U.S. Geological Survey shall not be held liable for improper or

incorrect use of the data described and/or contained herein.

This map was printed on an electronic plotter directly from digital files. 

Dimensional calibration may vary between electronic plotters and between X 

and Y directions on the same plotter, and paper may change size due to 

atmospheric conditions; therefore, scale and proportions may not be true on 

plots of this map.

This and other USGS information products are available at

http://store.usgs.gov/

U.S. Geological Survey

Box 25286, Denver Federal Center

Denver, CO 80225

To learn about the USGS and its information products visit

http://www.usgs.gov/

1-888-ASK-USGS, 1-888-275-8747

This report is available at:

http://pubs.usgs.gov/sim/3203/

Publishing support provided by:

Denver Science Publishing Network

Manuscript approved for publication on February 28, 2012 

For more information concerning this publication, contact:

Center Director, USGS Colorado Water Science Center

Box 25046, Mail Stop 415

Denver, CO 80225-0046

303-236-6900

Or visit the Colorado Water Science Center site at:

http://co.water.usgs.gov/

Suggested Citation: Kohn, M.S., 2012, Bathymetry of Totten

Reservoir, Montezuma County, Colorado, 2011: U.S. Geological

Survey Scientific Investigations Map 3203, scale 1:290

[http://pubs.usgs.gov/sim/3203/].

Bathymetry of Totten Reservoir, Montezuma County, Colorado, 2011

By

Michael S. Kohn

2012

station also continuously records its position. The rover communicates with the base station and is used to 

collect and record individual data points throughout the study area based on the position of the base station.

The daily water-surface elevation was determined from the RTK GPS survey-data points. The RTK GPS 

dataset included more than 6,000 data points obtained over the course of the study on the shoreline and in the 

shallow areas of the lake that were not navigable by boat. The shoreline was surveyed from a lake depth of 3 

ft to 2–3 ft above the top of the dam. 

All survey data were collected with a common coordinate system, geoid, ellipsoid, and datum. The 

coordinate system used was Universal Transverse Mercator (UTM), zone 12 north, the horizontal datum was 

North American Datum 1983 (NAD 83), and the vertical datum was North American Vertical Datum 1988 

(NAVD 88), Geoid 03, ellipsoid World Geodetic System 1984 (WGS 84). Data from the base station collected 

throughout the study were submitted to the National Geodetic Survey’s Online Positioning User Service 

(OPUS) Web site for processing (http://www.ngs.noaa.gov/OPUS/, accessed October 19, 2011). All survey 

data were recomputed to reflect the OPUS solution correction.

POST PROCESSING AND DATA ANALYSIS

The motion sensor in the multibeam sonar records the instrument’s motion in terms of pitch, roll, and 

heave. Pitch is the alternating rise and fall of the boat’s bow and stern, roll is rotation of the boat about its 

main axis, heave is the vertical rise and fall of the entire vessel, and yaw is the rotation of the sonar from the 

boat’s main axis. The ambient offsets of pitch, roll, and yaw were corrected using a calibration test, otherwise 

known as a patch test, as the instrument was not installed exactly vertical and in line with the boat’s main axis. 

From the patch test, the pitch offset angle was determined to be -15.5 degrees, the roll 1.0 degree, and the yaw 

5.5 degrees. 

 The post processing of the multibeam echo sounder bathymetry data was performed using HYPACK 

2011 from HYPACK, Inc. (HYPACK, Inc., 2011). All the data were filtered using the automated search and 

filter tool. Then, manual filtering was performed on the multibeam echo sounder bathymetry data to edit any 

spikes or inconsistencies the automated filter overlooked. Once all the data were filtered, the data were 

separated by the observation day. The multibeam echo sounder bathymetry data were interpolated onto a grid, 

with individual grid cells having sides of 6.56 ft, by computing the average depth in each cell and positioning 

the mean at the cell center.

The daily mean water surface elevation was computed from the gage height recorded at the gage located 

near the outlet structure. The multibeam echo sounder bathymetry data, which initially used the water-surface 

elevation as a datum, were converted to elevation (NAVD 88) using the daily mean water-surface elevation. 

The result was one dataset with a common horizontal and vertical datum (NAD 83 and NAVD 88). 

The bathymetry dataset was imported into Environmental Systems Research Institute (ESRI) ArcMap 

9.3.1 (Environmental Systems Research Institute, Inc., 2010) so the elevation contours and reservoir area and 

volume could be determined from the lake bottom to approximately 2–3 ft above the top of dam. Once the 

6.56-ft grid was created using HYPACK 2011, it was merged with the RTK GPS dataset in ArcMap by 

generating a triangulated irregular network (TIN) from both datasets. The TIN was then converted to a 6.56-ft 

horizontal grid, and using the contour tool in ArcMap, contours at intervals of 3 ft were produced. The areas 

and volumes at various elevations were computed using the surface volume tool in ArcMap (figs. 1–3, and 

table 1).

In figure 1, some of the upper contours are not continuous; this is mainly due to the spillway not allowing 

for the continuation of the contours as the spillway invert is below the elevation of the top of the dam. However, at the northeast end of the reservoir, near the inlet, sufficient data were not collected to resolve the 

contours causing the breaks. Where breaks in contours occurred, it was assumed the areas and volumes above 

that point were computed as if a vertical wall existed at that point. That assumption provided better results 

than using a high resolution digital elevation model. When comparing the 10-meter digital elevation model 

(DEM) (Gesch and others, 2002) at the reservoir with the data collected, it appeared that the DEM did not 

provide sufficient accuracy to improve the dataset collected for this report. Therefore, no DEM was used to 

supplement the dataset and the results of this report were generated only from field data.

BATHYMETRY OF TOTTEN RESERVOIR

From the RTK GPS data, the top of the dam was approximately 6,100 ft above NAVD 88, the spillway 

invert was 6,094 ft above NAVD 88, and full-pool elevation was 6,092 ft above NAVD 88. The invert 

elevation of the main outlet is approximately 6,076 ft above NAVD 88 (Ken Curtis, Dolores Water Conservancy District, written commun., Jan. 4, 2011). At the spillway elevation, the surface area of the lake is 243 ac 

and the volume is 2,940 ac-ft, of which, 42 ac-ft is in the dead pool. The minimum elevation of the reservoir 

is located 33 ft below the spillway elevation. As shown in figure 3, the volume increases very rapidly with 

depth initially, but at elevations greater than 6,078 ft above NAVD 88, the stage-volume curve is approximately linear.

SUMMARY

A better understanding of available water supply aids water managers in their operation of reservoirs 

during periods of drought and (or) high demand, and, should another bathymetric survey be conducted in the 

future, provides a dataset that also could be used to determine sedimentation infill rate and the useful lifespan 

of the reservoir. The U.S. Geological Survey, in cooperation with Dolores Water Conservancy District, carried 

out a bathymetry study of Totten Reservoir, Montezuma County, Colorado, from June 6–9, 2011. The study 

was performed using a man-operated boat-mounted multibeam echo sounder integrated with GPS navigation 

and RTK GPS. The vertical and horizontal precision of the multibeam echo sounder GPS as rated by the 

manufacturer are ±0.065 feet and ±0.032 feet, respectively. The vertical and horizontal precision of the RTK 

GPS as rated by the manufacturer are ±0.066 feet and ±0.033 feet, respectively. From the RTK GPS survey, 

the top of dam was approximately 6,100 feet above North American Vertical Datum 1988 (NAVD 88) and the 

spillway invert was 6,094 feet above NAVD 88. The two collected datasets were merged and imported into 

geographic information system software. The results of the study include a stage-surface area and stagevolume relations and bathymetric map. At the spillway elevation, the surface area of the lake is 243 acres and 

the volume is 2,940 acre-feet.

ABSTRACT

In order to better characterize the water supply capacity of Totten Reservoir, Montezuma County, 

Colorado, the U.S. Geological Survey, in cooperation with the Dolores Water Conservancy District, conducted 

a bathymetric survey of Totten Reservoir. The study was performed in June 2011 using a man-operated 

boat-mounted multibeam echo sounder integrated with a global positioning system and a terrestrial real-time 

kinematic global positioning system. The two collected datasets were merged and imported into geographic 

information system software. A bathymetric map of the reservoir was generated in addition to plots for the 

stage-area and the stage-volume relations.

INTRODUCTION

Totten Reservoir is owned and operated by the Dolores Water Conservancy District (DWCD), and water 

from the reservoir is used for recreation and irrigation of agricultural land. Because the storage capacity of 

Totten Reservoir is not documented and storage capacity information would aid water-resources managers in 

their operation of the reservoir during periods of drought and (or) high demand, the U.S. Geological Survey 

(USGS), in cooperation with the DWCD, conducted a bathymetric study of Totten Reservoir to determine the 

stage-surface area and stage-volume relations of the reservoir. This report provides water managers with a 

better understanding of available water supply in the reservoir and, should another bathymetric survey be 

conducted in the future, a dataset that also could be used to determine sedimentation infill rate and the useful 

lifespan of the reservoir. This report supports one of the USGS strategic directions of water supply by 

providing information related to the water census of the United States.

PURPOSE AND SCOPE

This report presents the results of the bathymetric evaluation of Totten Reservoir. The report contains a 

description of the data collection and analytical methods used to survey the reservoir and to develop datasets 

which aid water managers. A bathymetric map of the reservoir is presented with plots for the stage-area and 

the stage-volume relations.

DESCRIPTION OF STUDY AREA

Totten Reservoir is located in southwestern Colorado at 37°21'39" N. latitude and 108°32'06" W. longitude in central Montezuma County, just northeast of the town of Cortez (U.S. Geological Survey, 2011). 

Totten Reservoir is a man-made lake created by the impoundment of Rocky Ford Ditch (Holdren and Nelson, 

1998). Construction of the dam was completed in 1965 (Holdren and Nelson, 1998). The reservoir has a 

mean depth of 13.7 feet (ft) and maximum depth of 21 ft with a surface area of 241 acres (ac) (Holdren and 

Nelson, 1998). A hydrologic study of the reservoir revealed the average annual surface runoff and average 

annual groundwater inflows to the reservoir are approximately 183 acre-feet (ac-ft) and 223 ac-ft, respectively 

(Bureau of Reclamation, 1988).

The water rights in the reservoir are owned by the DWCD; however, recreational activities are permitted 

on the reservoir as Totten Reservoir is home to Totten Reservoir State Wildlife Area. Downstream from Totten 

Reservoir approximately 0.2 miles (mi), Rocky Ford Ditch flows into Simon Draw, a branch of McElmo 

Creek, a tributary of the San Juan River which feeds the Colorado River (U.S. Geological Survey, 2011).

BATHYMETRIC MEASUREMENT AND STORAGE ANALYSIS

The USGS performed a bathymetric survey of Totten Reservoir using a man-operated boat-mounted 

multibeam echo sounder integrated with a global positioning system (GPS) and a terrestrial real-time 

kinematic (RTK) GPS in June 2011. For the purposes of this report, data collected from both the boatmounted multibeam echo sounder and terrestrial RTK GPS will be considered bathymetric data. The multibeam echo sounder collected data at lake depths of approximately 3 feet and greater, whereas a terrestrial 

topographic survey was performed with the RTK GPS in shallow areas near the shore not navigable by boat to 

the elevation of the top of the dam plus about 2 to 3 additional feet. 

BATHYMETRIC MEASUREMENTS USED IN DATA COLLECTION

Bathymetric data from the multibeam echo sounder were collected June 6–8, 2011, using a Teledyne 

Odom Hydrographic ES3PT–M integrated multibeam echo sounder and motion sensor (Teledyne Odom 

Hydrographic, Inc., 2011) equipped with a Trimble SPS461 GPS receiver using procedures described in 

Wilson and Richards (2006). The vertical and horizontal precision of the multibeam echo sounder GPS as 

rated by the manufacturer are ±0.065 ft and ±0.032 ft, respectively (Trimble Navigation Limited, 2009b). The 

multibeam echo sounder has a swath width of 120 degrees capable of collecting data to depths of 197 ft. The 

echo sounder collects 240 data points at a sample frequency of 12 hertz (Hz); however, this varies with depth. 

The GPS generates position data at a rate of 5 Hz and navigational data at a rate of 1 Hz. A Teledyne Odom 

Hydrographic Real Time Appliance (RTA) was used for data synchronization of all aforementioned instruments resulting in a data string recorded at 1 Hz. The bathymetry data from the multibeam echo sounder were 

compiled and stored using the hydrographic survey software, HYPACK 2010 from HYPACK, Inc. (HYPACK, 

Inc., 2010). 

The multibeam echo sounder emits a pulse at a frequency of 240 kilohertz, which is reflected off the lake 

bed and detected by the receiver. The velocity of the pulse is affected by the lake temperature and salinity. 

For Totten Reservoir, a freshwater lake, the effect of salinity was assumed to be negligible (U.S. Army Corps 

of Engineers, 2002). Velocity profiles of Totten Reservoir were recorded using a Teledyne Odom Hydrographic Digibar-Pro velocity meter throughout the study and were used to correct the data during postprocessing (Teledyne Odom Hydrographic, Inc., 2001). Calibration points were obtained with the RTK GPS 

while the multibeam echo sounder was simultaneously recording to confirm the results.

The dam, principle outlet structure, and spillway also were surveyed using the RTK GPS. The terrestrial 

topographic survey was performed June 6–9, 2011, with a Trimble R8 GNSS RTK GPS receiver, a Trimble 

HPB450 radio modem, and a Trimble TSC2 controller. The vertical and horizontal precision of the RTK GPS 

as rated by the manufacturer are ±0.066 ft and ±0.033 ft, respectively (Trimble Navigation Limited, 2009a). 

The RTK GPS setup consisted of a base station, which included a receiver and radio, and a rover which 

consisted of a receiver and controller. The base station was located at a fixed position on the east end of the 

dam and receives information from satellites and transmits data to the rover’s receiver via the radio. The base 

ACKNOWLEDGMENTS

Several U.S. Geological Survey (USGS) employees helped with the data collection, including Jennifer L. 

Moore and Keelin R. Schaffrath. Kenneth R. Odom, now of Southern Company, Birmingham, Ala., provided 

help with the data collection along with assistance in organizing the data collection. Kristine L. Verdin and 

Barbara C. Ruddy (USGS) helped generate the map and associated graphics. The author would like to thank 

Paul J. Kinzel (USGS) for the onsite help and technical support he provided during the data collection and 

analysis, as well as comments he provided as a technical reviewer. Cory A. Williams (USGS) helped with the 

data collection and provided beneficial comments as a technical reviewer. The data collection was made 

easier by E.A. Birk of Dolores Water Conservancy District, who granted the survey crew access around the 

reservoir. Ken Curtis of Dolores Water Conservancy District provided previous survey information and 

helped to coordinate the study. 

REFERENCES CITED

Bureau of Reclamation, 1988, Chapter V - Salt loading calculations, supplement to definite plan report — 

Appendix B, Water Supply/Hydrosalinity, January, 1988, Dolores Project, Colorado.

Environmental Systems Research Institute, Inc., 2010, ArcGIS—A complete integrated system: Redlands, 

Calif, ESRI. Accessed Oct. 17, 2011, from http://www.esri.com/software/arcgis/.

Gesch, D., Oimoen, M., Greenlee, S., Nelson, C., Steuck, M., and Tyler, D., 2002, The National Elevation 

Dataset: Photogrammetric Engineering and Remote Sensing, v. 68, no. 1, p. 5-11.

Holdren, C., and Nelson, S.M., 1998, Water supply and water quality in Totten Reservoir, Montezuma County, 

Colorado: Bureau of Reclamation Technical Memorandum no. 8220–98–09, accessed Oct. 17, 2011, 

from http://www.usbr.gov/pmts/eco_research/9809.html

HYPACK, Inc., 2010, HYPACK® 10.0.5.31, Hydrographic survey software user manual: Middletown, Conn., 

HYPACK, Inc. [various paged], accessed Oct. 5, 2011, from 

http://www.hypack.com/new/Support/DocumentsManualsTechnicalArticlesetc/tabid/81/Default.aspx

HYPACK, Inc., 2011, HYPACK® 11.0.1.49, Hydrographic survey software user manual: Middletown, Conn., 

HYPACK, Inc. [various paged], accessed Oct. 5, 2011, from 

http://www.hypack.com/new/Support/DocumentsManualsTechnicalArticlesetc/tabid/81/Default.aspx

Trimble Navigation Limited, 2009a, Trimble® R8 GNSS receiver user guide, version 4.11, revision A: 

Dayton, Ohio, Trimble Navigation Limited, 50 p., accessed Nov. 4, 2011 from http://www.altop.com/sites/default/files/0Trimble_R8-R6-R4-5800M3_ENG.pdf

Trimble Navigation Limited, 2009b, Trimble® SPS461 specifications sheet: Dayton, Ohio, Trimble Navigation Limited, 2 p., accessed Nov. 4, 2011, from http://trl.trimble.com/docushare/dsweb/Get/Document445955/SPS461%20DGPS.pdf

Teledyne Odom Hydrographic, Inc., 2001, Digibar-Pro profiling sound velocimeter 1.0, Operation manual: 

Baton Rouge, La., Teledyne Odom Hydrographic, Inc. [various paged], accessed Nov. 4, 2011, from 

http://www.odomhydrographic.com/media/pdf/product_resources/84.pdf

Teledyne Odom Hydrographic, Inc., 2011, ES3PT 1.4, User manual: Baton Rouge, La., Teledyne Odom 

Hydrographic, Inc. [various paged], accessed Nov. 2, 2011, from 

http://www.odomhydrographic.com/media/pdf/product_resources/85.pdf

U.S. Army Corps of Engineers, 2002, Engineering and design, hydrographic surveying, Manual No. 1110-2-

1003: Washington, D.C., 510 p.

U.S. Geological Survey, 2011, Colorado StreamStats: U.S. Geological Survey, accessed Oct. 17, 2011, from 

http://streamstatsags.cr.usgs.gov/co_ss/default.aspx?stabbr=co&dt=1323879434710

Wilson, G.L., and Richards, J.M., 2006, Procedural documentation and accuracy assessment of bathymetric 

maps and area/capacity tables for small reservoirs: U.S. Geological Survey Scientific Investigations 

Report 2006–5208, p. 2–7.

 

Base from U.S. Geological Survey digital data, 2011

Universal Transverse Mercator projection, Zone12 North

Horizontal coordinate information is referenced to the North American Datum 

of 1983 (NAD 83)

Figure 1. Bathyetric contours of Totten Reservoir, Montezuma County, Colorado, 2011 (not for navigational use).

108°32'00"

108°32'00"

108°31'45"

108°31'45"

108°31'30"

108°31'30"

37°21'45"

37°21'45"

37°22'15"

37°22'15"

37°22'15"

37°22'15"

37°22'00"

37°22'00"

0 100 200 300 METERS

0 200 400 600 800 1,000 FEET

CONTOUR INTERVAL 3 FEET

NORTH AMERICAN VERTICAL DATUM OF 1988 

Dam

Spillway

Rocky Ford Ditch

6,072

6,075

6,078

6,078

6,075

6,072

6,069

6,072

6,069

6,075

6,072

6,069

6,066

6,063

6,075

6,078

6,078

6,081

6,084

6,078

6,081

6,081

6,081

6,078

6,078

6,081

6,099

6,102

6,084

6,087

6,090 

6,099

6,102

6,084

6,081

6,084

6,087

6,090

6,093

6,096 6,099

6,102

6,102

6,102

6,102

6,099

6,096

6,093

6,090

6,087

6,084

6,081

6,078

6,078

6,099

6,096

6,093

6,096

6,093

6,099

6,102

6,099

6,096

6,093

6,090

EXPLANATION

Bathymetric contour—Line of equal lake-bottom

 elevation, in feet above NAVD 88. Interval is 3

 feet. Hachures indicate depression

Lake boundary—Edge of water at lake-surface

 elevation, 6,092 feet above NAVD 88

0 50 6,055

6,060

6,065

6,070

6,075

6,080

6,085

6,090

6,095

6,100

6,105

6,110

100 150

Reservoir surface area, in acres

Stage elevation, in feet (NAVD 88)Stage elevation, in feet (NAVD 88)

200 250 300

Figure 2. Stage-surface area curve of Totten Reservoir, Montezuma County, Colorado, 2011.

0 1,000 6,055

6,060

6,065

6,070

6,075

6,080

6,085

6,090

6,095

6,100

6,105

6,110

2,000 3,000

Reservoir volume, in acre-feet

4,000 5,000 6,000

Figure 3. Stage-volume curve of Totten Reservoir, Montezuma County, Colorado, 2011.

Table 1. Stage-surface area and stage-volume

 relation for selected elevations of Totten

 Reservoir, Montezuma County, Colorado, 2011.

Stage elevation,

in feet (NAVD 88)

Stage-surface

area, in acres

Stage-volume,

in acre-feet

6,061 0.000 0.000

6,062 0.017 0.003

6,063 0.131 0.077

6,064 0.238 0.262

6,065 0.358 0.549

6,066 0.641 1.05

6,067 0.905 1.82

6,068 1.16 2.84

6,069 1.57 4.20

6,070 2.07 6.01

6,071 2.76 8.41

6,072 3.92 11.7

6,073 5.38 16.3

6,074 7.03 22.5

6,075 9.50 30.7

6,076 15.5 42.4

6,077 35.4 66.9

6,078 63.5 116

6,079 89.5 193

6,080 112 294

6,081 128 414

6,082 140 548

6,083 152 695

6,084 162 852

6,085 173 1,020

6,086 185 1,200

6,087 197 1,390

6,088 206 1,590

6,089 213 1,800

6,090 219 2,020

6,091 225 2,240

6,092 231 2,470

6,093 237 2,700

6,094 243 2,940

6,095 249 3,190

6,096 254 3,440

6,097 259 3,700

6,098 264 3,960

6,099 269 4,220

6,100 273 4,490

6,101 277 4,770

6,102 281 5,050

6,103 286 5,330

COLORADO

Index map

Montezuma

County

Totten Reservoir

Cortez

Prepared in cooperation with the

Dolores Water Conservancy District

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Map 3203

Kohn, M.S., Bathymetry of Totten Reservoir, Montezuma County, Colorado, 2011