Barbara C. Ruddy, U.S. Geological Survey, Hydrologist 20130118 vector digital data Reston, Virginia USGS https://water.usgs.gov/lookup/getspatial?sim2012-3202GroundhogResContours Michael S. Kohn 2013 https://pubs.usgs.gov/sim/3202/ The U.S. Geological Survey performed a bathymetric survey of Groundhog 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. The multi-beam echo sounder collected data at lake depths of approximately 3 feet and greater, whereas the 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 data from the multibeam echo sounder were collected June 27-29, 2011, and were compiled and stored using the hydrographic survey software, HYPACK 2010 from HYPACK, Inc. (HYPACK, Inc., 2010). The data were interpolated onto a 2-meter grid by computing the average of the data in each cell and positioning the mean at the cell center. The data were converted to elevation above the National Vertical Datum 1988 (Gesch and others, 2002) using reservoir stage. The bathymetry and GPS datasets were then imported into ESRI Arcmap so elevation contours could be determined. The data were used to create a Triangulate Irregular Network (TIN). This TIN was converted to a 2-meter raster dataset which was subsequently contoured. The contour lines were smoothed using a generalized 500 technique (ESRI, 2010). Some holes in the smoothed contour dataset were removed manually and some of the contours were manually adjusted to connect contours and fix any other issues. This created the final contour map.References: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.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.aspxKohn, M.S., 2012, Bathymetry of Groundhog Reservoir, Dolores County, Colorado, 2011: U.S. Geological Survey Scientific Investigations Map 3202, scale 1:8,000 [https://pubs.usgs.gov/sim/3202/].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=1323879434710 The U.S. Geological Survey, in cooperation with the Dolores Water Conservancy District, conducted a bathymetric survey of Groundhog Reservoir, Dolores County, Colorado, in order to characterize the water supply capacity of the 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. Additionally, stage-area and stage-volumes relations were developed and plots were made. Data Quality: The accuracy of the data is considered to be good. The bathymetric data were collected using a Teldyne 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 dam, principle outlet structure, and spillway also were surveyed using the RTK GPS. The terrestrial topographic survey was performed using 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 daily water-surface elevation was determined from the RTK GPS survey-data points. The RTK GPS dataset not only included more than 700 water-surface elevation points over the course of the study, but almost 6,000 data points were obtained 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. 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 10 ft were produced. The areas and volumes at various elevations were computed using the surface volume tool in ArcMap. Some of the upper contours are not continuous; this is mainly due to the spillway and irrigation canal not allowing for the continuation of the contours as the spillway and canal inverts are below the elevation of the top of the dam. However, in the northwest end of the reservoir and east of the Nash Creek 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. The data are presented in: Kohn, M.S., 2012, Bathymetry of Groundhog Reservoir, Dolores County, Colorado, 2011: U.S. Geological Survey Scientific Investigations Map 3202, scale 1:8,000 [https://pubs.usgs.gov/sim/3202/]. Other references cited: 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. HYPACK, Inc., 2011, 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.al-top.com/sites/default/files/0Trimble_R8-R6-R4-5800M3_ENG.pdf Trimble Navigation Limited, 2009b, Trimble® SPS461 specifications sheet: Dayton, Ohio, Trimble Naviga-tion Limited, 2 p., accessed Nov. 4, 2011, from http://trl.trimble.com/docushare/dsweb/Get/Document-445955/SPS461%20DGPS.pdf Teledyne Odom Hydrographic, Inc., 2011, ES3PT 1.4, User manual: Baton Rouge, La., Teledyne Odom Hydrographic, Inc. [variously paged], accessed Nov. 2, 2011, from http://www.odomhydrographic.com/media/pdf/product_resources/85.pdf 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. 20110627 20110629 Data were collected from June 27 through 29, 2011. Complete None planned -108.313598 -108.283896 37.812585 37.783011 USGS Thesaurus bathymetric survey USGS Thesaurus Groundhog Reservoir ISO 19115 Topic Categories elevation inlandWaters Geographic Names Information System Groundhog Reservoir Geographic Names Information System southwestern Colorado Geographic Names Information System Dolores County None June 2011 USGS Metadata Identifier USGS:0a482d5f-b106-445b-9c7b-5b8e6ac05334 None Although these data have been used by the U.S. Geological Survey, Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of these data, software, or related materials. The use of firm, trade, or brand names in this report is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey. The names mentioned in this document may be trademarks or registered trademarks of their respective trademark owners. U.S. Geological Survey Barbara C. Ruddy Hydrologist mailing

Box 25046, MS 415

Denver CO 80225 US 303.236.6916 303.236.4912 bcruddy@usgs.gov https://water.usgs.gov/GIS/browse/groundhogResContours.jpg Illlustration of data set jpg Prepared in cooperation with the Dolores Water Conservancy District None Unclassified None Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; ESRI ArcGIS 10.0.5.4400 topology present complete The accuracy of the data is considered to be good. The bathymetric data were collected using a Teldyne 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 dam, principle outlet structure, and spillway also were surveyed using the RTK GPS. The terrestrial topographic survey using 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 daily water-surface elevation was determined from the RTK GPS survey-data points. The RTK GPS dataset not only included more than 700 water-surface elevation points over the course of the study, but almost 6,000 data points were obtained 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. 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 10 ft were produced. The areas and volumes at various elevations were computed using the surface volume tool in ArcMap. Some of the upper contours are not continuous; this is mainly due to the spillway and irrigation canal not allowing for the continuation of the contours as the spillway and canal inverts are below the elevation of the top of the dam. However, in the northwest end of the reservoir and east of the Nash Creek 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. 2012 Vector String 17 Transverse Mercator 0.9996 -111.0 0.0 1640419.947506562 0.0 coordinate pair 0.000000007283529335211371 0.000000007283529335211371 meters D North American 1983 GRS 1980 6378137.0 298.257222101 GroundhogResContours These are the bathymetric contour lines in elevation above the National Vertical Datum 1988. National Vertical Datum 1988 FID Internal feature number. ESRI Sequential unique whole numbers that are automatically generated. 011 Shape Feature geometry. Coordinates defining the features ESRI Coordinates defining the features. polyline Coordinates defining the features ESRI 20130108 20130108 011 ID Unique whole numbers ESRI 0 399 none 20130108 20130108 011 CONTOUR Elevation of reservoir bottom in whole feet. National Vertical Datum 1988 8650 8740 20110627 20110629 011 Length Length of feature ESRI 576 46000 011 U.S. Geological Survey Michael Ierardi mailing

445 National Center

Reston VA 20192 US 1-888-275-8487 (1-888-ASK-USGS) mierardi@usgs.gov Although this data set has been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed or implied is made by the U.S. Geological Survey as to the accuracy of the data and related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this data, software, or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Shapefile 0.117 https://water.usgs.gov/GIS/dsdl/GroundhogResContours.zip None. This dataset is provide by USGS as a public service. 20201117 U.S. Geological Survey Ask USGS -- Water Webserver Team mailing

445 National Center

Reston VA 20192 1-888-275-8747 (1-888-ASK-USGS) mierardi@usgs.gov FGDC Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998