The Hydrologic Engineering Center’s Hydrologic Modeling System (HEC-HMS) and Hydrologic Engineering Center’s River Analysis System (HEC-RAS) computer programs, developed by the U.S. Army Corps of Engineers, were used for the hydrologic and hydraulic modeling, respectively, to analyze the potential for dam failure under different hydrologic conditions. The hydrologic assessment was designed to determine the outflow hydrographs and peak discharges for Lago El Guineo and other subbasins in the Río Grande de Manatí hydrographic basin for three extreme rainfall events: (1) a 6-hour probable maximum precipitation event, (2) a 24-hour probable maximum precipitation event, and (3) a 24-hour, 100-year recurrence rainfall event. The hydraulic study simulated a dam failure of Lago El Guineo Dam using flood hydrographs generated from the hydrologic study. The simulated dam failure generated a hydrograph that was routed downstream from Lago El Guineo Dam through the lower reaches of the Río Toro Negro and the Río Grande de Manatí to determine water-surface profiles developed from the event-based hydrologic scenarios and “sunny day” conditions. This USGS data release contains all of the input and output files for the simulations described in the associated model documentation report (http://doi.org/10.3133/sir20165070). This data release also includes (1) geospatial data of the watersheds (2) precipitation depths for use in the model, and (3) HEC-HMS and HEC-RAS source codes.