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Heriberto Torres-Sierra

Publications and source records attributed to Heriberto Torres-Sierra.

14 recordsLinked to original sources
USGS2016

Dam failure analysis for the Lago El Guineo Dam, Orocovis, Puerto Rico

The U.S. Geological Survey, in cooperation with the Puerto Rico Electric Power Authority, completed hydrologic and hydraulic analyses to assess the potential hazard to human life and property associated with the hypothetical failure of the Lago El Guineo Dam. The Lago El Guineo Dam is within the headwaters of the Río Grande de Manatí and impounds a drainage area of about 4.25 square kilometers. 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. 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. The flow routing in the hydraulic analyses was completed using the unsteady flow module available in the HEC–RAS model. Above the Lago El Guineo Dam, the simulated inflow peak discharges from HEC–HMS resulted in about 550 and 414 cubic meters per second for the 6- and 24-hour probable maximum precipitation events, respectively. The 24-hour, 100-year recurrence storm simulation resulted in a peak discharge of about 216 cubic meters per second. For the hydrologic analysis, no dam failure conditions are considered within the model. The results of the hydrologic simulations indicated that for all hydrologic conditions scenarios, the Lago El Guineo Dam would not experience overtopping. For the dam breach hydraulic analysis, failure by piping was the selected hypothetical failure mode for the Lago El Guineo Dam. Results from the simulated dam failure of the Lago El Guineo Dam using the HEC–RAS model for the 6- and 24-hour probable maximum precipitation events indicated peak discharges below the dam of 1,342.43 and 1,434.69 cubic meters per second, respectively. Dam failure during the 24-hour, 100-year recurrence rainfall event resulted in a peak discharge directly downstream from Lago El Guineo Dam of 1,183.12 cubic meters per second. Dam failure during sunny-day conditions (no precipitation) produced a peak discharge at Lago El Guineo Dam of 1,015.31 cubic meters per second assuming the initial water-surface elevation was at the morning-glory spillway invert elevation. The results of the hydraulic analysis indicate that the flood would extend to many inhabited areas along the stream banks from the Lago El Guineo Dam to the mouth of the Río Grande as a result of the simulated failure of the Lago El Guineo Dam. Low-lying regions in the vicinity of Ciales, Manatí, and Barceloneta, Puerto Rico, are among the regions that would be most affected by failure of the Lago El Guineo Dam. Effects of the flood control (levee) structure constructed in 2000 to provide protection to the low-lying populated areas of Barceloneta, Puerto Rico, were considered in the hydraulic analysis of dam failure. The results indicate that overtopping can be expected in the aforementioned levee during 6- and 24-hour probable maximum precipitation events. The levee was not overtopped during dam failure scenarios under the 24-hour, 100-year recurrence rainfall event or sunny-day conditions.

Orocovis↗
USGS2015

Dam failure analysis for the Lago de Matrullas Dam, Orocovis, Puerto Rico

The U.S. Geological Survey, in cooperation with the Puerto Rico Electric Power Authority, completed a hydrologic and hydraulic study to assess the potential hazard to human life and property associated with the hypothetical failure of the Lago de Matrullas Dam, located within the headwaters of the Río Grande de Manatí. The hydrologic study yielded outflow hydrographs and peak discharges for Lago de Matrullas and other subbasins in the Río Grande de Manatí hydrographic basin for three extreme rainfall events: (1) a 6-hour probable maximum precipitation (PMP) event, (2) a 24-hour PMP event, and (3) a 100-year-recurrence, 24-hour rainfall event. The hydraulic study simulated the hypothetical dam failure of Lago de Matrullas using hypothetical flood hydrographs generated from the hydrologic study and selected dam breach parameters. The flood wave resulting from the failure was downstream-routed through the lower reaches of the Río Matrullas, the Río Toro Negro, and the Río Grande de Manatí for determination of water-surface profiles developed from the event-based hydrologic scenarios and “sunny day” (no precipitation) conditions. The Hydrologic Modeling System (HEC–HMS) and the River Analysis System (HEC–RAS) computer programs, developed by the Hydrologic Engineering Center (HEC) of the U.S. Army Corps of Engineers, were used for the hydrologic and hydraulic modeling, respectively. The flow routing in the hydraulic analyses was performed using the unsteady-state flow module available in the HEC–RAS model. At the Lago de Matrullas Dam, inflow peak discharges of about 1,104 and 1,032 cubic meters per second (m 3 /s) were estimated with HEC–HMS for the 6- and 24-hour PMP events, respectively. The 100-year recurrence, 24-hour rainfall event simulation resulted in a peak discharge of about 418 m 3 /s. For the hydrologic analysis, no dam failure conditions were considered with the model. The results of the hydrologic simulations indicated, however, that the dam would be overtopped by the simulated 6- and 24-hour PMP events. Unlike the 6- and 24-hour PMP events, no overtopping was observed during the simulated 100-year recurrence, 24-hour rainfall event. For the dam-breach hydraulic analysis, the hypothetical failures of the Lago de Matrullas Dam included two possible failure modes: overtopping and piping. Overtopping failure was evaluated in this study for the 6- and 24- hour probable-maximum-precipitation breach scenarios. Piping dam failure was simulated for sunny day conditions and for the 100-year-recurrence, 24-hour rainfall scenario. Results from the simulated dam failure of the Lago de Matrullas Dam using the HEC–RAS model for the 6- and 24-hour PMP events showed peak discharges at the dam of 3,149.33 and 3,604.70 m 3 /s, respectively. Dam failure during the 100-year-recurrence, 24-hour rainfall event resulted in a peak discharge of 2,103.12 m 3 /s directly downstream from the dam. Dam failure under sunny day conditions produced a peak discharge of 1,695.91 m 3 /s at the dam assuming the antecedent lake level was at the morning-glory spillway invert elevation. Flood-inundation maps prepared as part of the study depict the flood extent and provide valuable information for preparing an Emergency Action Plan. Results of the failure analysis indicate that a failure of the Lago de Matrullas Dam could cause flooding to many of the inhabited areas along stream banks from the Lago de Matrullas Dam to the mouth of the Río Grande de Manatí. Among the areas most affected are the low-lying regions in the vicinity of the towns of Ciales, Manatí, and Barceloneta. The delineation of the flood boundaries near the town of Barceloneta considered the effects of a levee constructed during 2000 at Barceloneta in the flood plain of the Río Grande de Manatí to provide protection against flooding to the near-by low-lying populated areas. The results showed overtopping can be expected in the aforementioned levee during 6- and 24-hour probable-maximum-precipitation dam failure scenarios. No overtopping of the levee was simulated, however, during dam failure scenarios under the 100-year recurrence, 24-hour rainfall event or sunny day conditions.

Orocovis↗
USGS2001

The rainfall-triggered landslide and flash-flood disaster in northern Venezuela, December 1999

Rainstorms in December 1999 induced thousands of landslides along the northern slopes of the Cordillera de la Costa mountain range principally in the state of Vargas, Venezuela . Rainfall accumulation of 293 millimeters during the first 2 weeks of December was followed by an additional 911 millimeters of rainfall on December 14 through 16. The landslides and floods inundated coastal communities resulting in a catastrophic death toll estimated at between 15,000 and 30,000 people. Debris flow damage to houses, buildings, and infrastructure in the narrow coastal zone was severe. Flash floods on alluvial fans at the mouths of rivers draining the coastal mountain range also contributed to the general destruction. In time scales spanning decades to centuries, the alluvial fans along this Caribbean coastline are areas of high geomorphic activity. Because most of the coastal zone in Vargas consists of steep mountain fronts that rise directly from the Caribbean Sea, the alluvial fans provide the only relatively flat areas upon which to build. Rebuilding and reoccupation of these areas requires careful determination of hazard zones to avoid future loss of life and property. A limited assessment of the distribution and character of landslides is currently in progress by the U.S. Geological Survey in cooperation with the Venezuelan Ministry of Environment and Natural Resources.

Conference Paper↗
USGS2001

Natural hazards on alluvial fans: the debris flow and flash flood disaster of December 1999, Vargas state, Venezuela

Large populations live on or near alluvial fans in locations such as Los Angeles, California, Salt Lake City, Utah, Denver, Colorado, and lesser known areas such as Sarno, Italy, and Vargas, Venezuela. Debris flows and flash floods occur episodically in these alluvial fan environments, and place many communities at high risk during intense and prolonged rainfall. In December 1999, rainstorms induced thousands of landslides along the Cordillera de la Costa, Vargas, Venezuela. Rainfall accumulation of 293 mm during the first 2 weeks of December was followed by an additional 911 mm of rainfall on December 14 through 16. Debris flows and floods inundated coastal communities resulting in a catastrophic death toll of as many as 30,000 people. Flash floods and debris flows caused severe property destruction on alluvial fans at the mouths of the coastal mountain drainage network. In time scales spanning thousands of years, the alluvial fans along this Caribbean coastline are dynamic zones of high geomorphic activity. Because most of the coastal zone in Vargas consists of steep mountain fronts that rise abruptly from the Caribbean Sea, the alluvial fans provide practically the only flat areas upon which to build. Rebuilding and reoccupation of these areas requires careful determination of hazard zones to avoid future loss of life and property. KEY TERMS: Debris flows, flash floods, alluvial fans, natural hazards, landslides, Venezuela

Conference Paper↗
USGS1997

Hurricane Hortense: impact on surface water in Puerto Rico

Late Monday night, September 9, and into the early morning hours of Tuesday, September 10, 1996, Hurricane Hortense passed over the southwestern part of Puerto Rico (inset). Hurricane Hortense made landfall as a Category One Hurricane (74 to 95 miles per hour) on the Saffir-Simpson Scale, with maximum sustained winds of nearly 80 miles per hour. The eye of Hurricane Hortense moved over the towns of Guayanilla, Yauco, Guánica, Lajas, San Germán, Cabo Rojo, Hormigueros, and Mayagüez (fig. 1).

Fact Sheet↗
USGS1987

Estimated water use in St. Croix, U.S. Virgin Islands, October 1983-September 1985

St. Croix is the largest of the U.S. Virgin Islands, with a land area of 82 square miles. The island is located about 60 miles east-southeast of Puerto Rico and about 40 miles south of St. Thomas and St. John (fig. 1). St. Croix has experienced a dramatic increase in its population over the last 25 years, growing from about 15,000 inhabitants in 1960 to about 54,000 in 1985 (personal communication, U.S. Virgin Islands Planning Office). Tourism development has also resulted in a large transient population with demands for services and facilities. The population and economic growth of St. Croix has resulted in a significant increase in the demand and supply of water (fig. 2).

Virgin Islands↗