This dataset is a polyline shapefile containing bathymetric contours, at 1-meter intervals, of Lago Guayabal, Villalba, Puerto Rico. The contours were generated from bathymetric data collected during a sedimentation survey conducted during the period December 11- December 14, 2017 by the Puerto Rico office of the Caribbean-Florida Water Science Center of the U.S. Geological Survey (USGS). The goals of the survey were to determine reservoir infill sedimentation rates, generate a bathymetric map of the reservoir, and create a stage-volume relation. Field techniques used during the survey were similar to those outlined by Soler-López (2008) and Wilson and Richards (2006). More than 270,000 water-depth points were surveyed along 60 navigation lines used in previous sedimentation surveys (Soler-López, 2003, 2008). All water-depth data were collected using a Teledyne-Odom Echotrac CVM depth sounder coupled to a Global Positioning System (GPS). Esri ArcGIS, version 10.5 (reference similar to that in metadata for point shapefile), was used to edit the depth data and create a triangulated irregular network (TIN) model, from which bathymetric contours and a stage-volume relation were generated . References: Soler-López, L.R., 2003, Sedimentation History of Lago Guayabal, Puerto Rico, 1913-2001: U.S. Geological Survey Water-Resources Investigations Report 03-4198, 28 p, 2 pls. Soler-López, L.R., 2008, Comparison of Storage Capacity and Sedimentation Trends of Lago Guayabal, Puerto Rico, December 2001 and October 2006: U.S. Geological Survey Scientific Investigation Map 2008-3016, 1 sheet Wilson, G.L., and Richards, J.M., 2006, Procedural Documentation and Accuracy Assessment of Bathymetric Map and Area/Capacity Tables for Small Reservoirs, U.S. Geological Survey-Scientific Investigation Report 2006-5208, 24 p. plus oversize figs,https://pubs.usgs.gov/sir/2006/5208/pdf/SIR-06-5208.pdf.