Bathymetry of Deadmans Lake, Golf Course Reservoir 9, Ice Lake, Kettle Lakes 1–3, and Non-Potable Reservoirs 1–4 at the U.S. Air Force Academy, Colorado, 2019

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The U.S. Geological Survey, in cooperation with the U.S. Air Force Academy (USAFA), carried out bathymetric and topographic surveys to characterize the volume of Deadmans Lake, Golf Course Reservoir 9, Ice Lake, Kettle Lakes 1–3, and Non-Potable Reservoirs 1–4 at the U.S. Air Force Academy, Colorado. 

The study is meant to improve reservoir regulation and operation during periods of drought or high demand so that the lakes and reservoirs can be monitored using stage and volume gages.

This study provides an updated characterization of storage capacity and improved understanding of present
(2019) water capacity in the lakes and reservoirs at the USAFA, which will  improve reservoir regulation and operation during periods of drought or high demand so that the lakes and reservoirs can be monitored using stage and volume gages.

In addition, these surveys serve as a baseline that could be compared with future surveys of the lakes and reservoirs.

Bathymetric maps of each lake and reservoir are presented with figures of the elevation-volume curves in the Scientific Investigations Map (Kohn and Hempel (2020)). The bathymetric surveys for this study were carried out from October 15, 2019, to December 12, 2019, using a manually operated, boat-mounted, single-beam echo sounder integrated with a Real-Time Kinematic (RTK) Global Navigation Satellite Systems (GNSS) receiver. Topographic surveys were carried out during the same time period using RTK GNSS to collect elevation data at and above the water surface and up to the elevation of the dam or spillway at the time of the surveys. The topographic and bathymetric datasets were imported into Esri ArcMap 10.7.1. The combined survey points were then interpolated into digital elevation models (DEMs), which were used to determine lake or reservoir volumes that correspond to water-surface elevations between the lakebed and the approximate top of the dam or spillway.

The elevation and volume data at specified elevations for each lake or reservoir and the combined topographic and bathymetric RTK GNSS survey points and bathymetric DEMs are published in Kohn and Hempel (2020).

The data for Deadmans Lake, Golf Course Reservoir 9, Ice Lake, Kettle Lakes 1–3, and Non-Potable Reservoirs 1–4 are presented in the following formats:

 

1.  Table:

Elevation of the spillway crest, main outlet structure, dam crest, and top of outlet tower for Deadmans Lake, Golf Course Reservoir 9, Ice Lake, Kettle Lakes 1–3, and Non-Potable Reservoirs 1–4, U.S. Air Force Academy, Colorado, 2019.

[NAVD 88, North American Vertical Datum of 1988; NA, not applicable because feature did not exist; NS, not surveyed because feature was submerged beneath the water surface and not accessible]

Lake or reservoir Spillway crest elevation, in U.S. survey feet (NAVD 88) Spillway crest elevation, in feet (NAVD 88) Main outlet structure elevation, in U.S. survey feet (NAVD 88) Main outlet structure elevation, in feet (NAVD 88) Dam crest elevation, in U.S. survey feet (NAVD 88) Dam crest elevation, in feet (NAVD 88) Top of the outlet tower elevation, in U.S. survey feet (NAVD 88) Top of the outlet tower elevation, in feet (NAVD 88)
Deadmans Lake NA NA 7,187.67 7,187.68 7,190.35 7,190.36 NA NA
Golf Course Reservoir 9 6,927.61 6,927.62 6,924.23 6,924.24 6,929.91 6,929.92 NA NA
Ice Lake 6,373.30 6,373.31 6,372.14 6,372.15 6,375.17 6,375.18 NA NA
Kettle Lake 1 6,457.42 6,457.43 6,455.59 6,455.60 6,459.31 6,459.32 NA NA
Kettle Lake 2 NA NA 6,474.64 6,474.65 6,481.05 6,481.06 NA NA
Kettle Lake 3 6,487.68 6,487.69 6,485.21 6,485.22 6,488.09 6,488.10 NA NA
Non-Potable Reservoir 1 6,573.02a 6,573.03a NS NS 6,584.79 6,584.80 6,584.13 6,584.14
Non-Potable Reservoir 2 6,898.45 6,898.46 NS NS 6,902.03 6,902.04 6,904.26 6,904.27
Non-Potable Reservoir 3 6,963.26 6,963.27 NS NS 6,968.06 6,968.07 6,969.16 6,969.17
Non-Potable Reservoir 4 7,201.99b 7,202.00b NS NS 7,209.74 7,209.75 7,206.22 7,206.23
a Two spillways are present at Non-Potable Reservoir 1, so values from the lower spillway, the north spillway, are listed here and the south spillway crest is at an elevation of 6,579.17 U.S. survey feet (6,579.18 feet) above NAVD 88.
b The spillway was located on the outlet tower above the main outlet structure and was not a separate channel on the ground adjacent to the reservoir.

 

2. Map Sheet - Bathymetric maps of the features.

Bathymetric DEMs (map sheet) were used to determine lake or reservoir volumes that correspond to water-surface elevations between the lakebed and the approximate top of the dam or spillway.

3. FIGURE - Elevation-volume curves

Lake and reservoir volumes were computed at specified elevation ranges using the Surface Volume tool in ArcMap (Esri, 2020) and were compiled into elevation-volume curves

4. TABLE:

Water-surface elevations and volumes of Deadmans Lake, Golf Course Reservoir 9, Ice Lake, Kettle Lakes 1–3, and Non-Potable Reservoirs 1–4, U.S. Air Force Academy, Colorado, during the bathymetric survey, fall 2019.
[NAVD 88, North American Vertical Datum of 1988]
Lake or reservoir Date of survey Water-surface elevation during bathymetric survey, in U.S. survey feet (NAVD 88) Water-surface elevation during bathymetric survey, in feet (NAVD 88) Volume during bathymetric survey, in acre-feet
Deadmans Lake November 14, 2019 7,184.92 7,184.93 9.24
Golf Course Reservoir 9 October 15, 2019 6,920.83 6,920.84 1.81
Ice Lake October 18, 2019 6,369.53 6,369.54 16.25
Kettle Lake 1 October 15, 2019 6,455.70 6,455.71 18.75
Kettle Lake 2 October 16, 2019 6,474.69 6,474.70 33.91
Kettle Lake 3 October 17, 2019 6,485.29 6,485.30 47.14
Non-Potable Reservoir 1 November 15, 2019 6,568.24 6,568.25 102.36
Non-Potable Reservoir 2 November 12, 2019 6,895.64 6,895.65 309.14
Non-Potable Reservoir 3 November 13, 2019 6,958.78 6,958.79 113.04
Non-Potable Reservoir 4 November 14, 2019 7,187.65 7,187.66 4.50