Hamilton Reservoir at Hamilton, Missouri, 2019

Water supply lakes are the primary source of water for many communities in northern and western Missouri. Therefore, accurate and up-to-date estimates of lake capacity are important for managing and predicting adequate water supply. Many of the water supply lakes in Missouri were previously surveyed by the U.S. Geological Survey in the early 2000s (Richards, 2013) and in 2013 (Huizinga, 2014); however, years of potential sedimentation may have resulted in reduced water storage capacity. Periodic bathymetric surveys are useful to update the area/capacity table and to determine changes in the bathymetric surface. Hamilton Reservoir is a water supply lake used by the city of Hamilton in northwestern Missouri. The surface area of Hamilton Reservoir is about 87 acres at the primary overflow spillway elevation (926.4 feet above the North American Vertical Datum of 1988). A previous bathymetric survey was completed in 2000 with a single-beam echosounder. In July 2019, the U.S. Geological Survey, in cooperation with the Missouri Department of Natural Resources and the City of Hamilton, completed a bathymetric survey of Hamilton Reservoir using a multibeam echosounder. The water-surface elevation during the survey was about 926.24 feet. Supplemental data were collected in shallow areas using an acoustic Doppler current profiler (ADCP) mounted on a remote-controlled vessel equipped with a differential global positioning system (DGPS), as well as discrete GPS data. These data can be combined with light detection and ranging (lidar) data to prepare a bathymetric map and a surface area and capacity table for the lake. These data also can be used to compare the current bathymetric surface with the previous bathymetric surface. Based on a comparison of the elevation of coincident points in the 2000 and 2019 surveys (elevation of the spillway crest), the 2000 survey data needed to be adjusted upward by 3.04 feet to match the elevation and datum of the 2019 survey. Because of the advances in surveying techniques and accuracy since the previous surveys, it was assumed that the 2019 elevation was the more accurate value. The gridded bathymetric point data (HamiltonRes2019_bathy_pts.zip) were computed on a 1.64-foot (0.50-meter) grid using the Combined Uncertainty and Bathymetry Estimator (CUBE) method, which is used as the source of points to create the bathymetric surface. Bathymetric quality-assurance data (HamiltonRes2019_QA_raw.zip) were collected to evaluate the vertical accuracy of the gridded bathymetric point data. Each of these two zip files contains a shapefile with an attribute table. Attribute/column labels of each table are described in the "Entity and attribute" section of the metadata file. References Cited: Huizinga, R.J., 2014, Bathymetric surveys and area/capacity tables of water-supply reservoirs for the city of Cameron, Missouri, July 2013: U.S. Geological Survey Open-File Report 2014–1005, 15 p., http://dx.doi.org/10.3133/ofr20141005. Richards, J.M., 2013, Bathymetric surveys of selected lakes in Missouri—2000–2008: U.S. Geological Survey Open-File Report 2013–1101, 9 p. with appendix, http://pubs.usgs.gov/of/2013/1101.