Suspended-sediment data in the upper Rio Grande De Loiza basin, Puerto Rico

Guzman-Rios, Senen

doi:10.3133/ofr88324

Cited by 2 publications

(3 citation statements)

References 6 publications

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“…Suspended and bed load sediment transport data were compiled from previous USGS studies to summarize annual yield [Guzmán-Ríos, 1989;Larsen, 1997;Simon and Guzmán-Ríos, 1990;USGS, 1999]. Annual runoff data were derived from a USGS data base for a surface-water gaging station, USGS ID 50051310, at the outlet of the Cayaguás watershed [USGS, 1999].…”

Section: Fluvial Sediment and Runoffmentioning

confidence: 99%

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Mass wasting and sediment storage in a small montane watershed: An extreme case of anthropogenic disturbance in the humid tropics

Larsen¹,

Román²

2001

Geomorphic Processes and Riverine Habitat

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By the peak of land-use conversion for subsistence cropping and plantation agriculture in Puerto Rico in the 1940's, 94 percent of the original forest cover had been eliminated. In a small (26.4 km 2) upland watershed that typifies this land-use history, field surveys and examination of aerial photographs indicate that more than 2,000 landslides have occurred since about 1820 when forest clearing began. The landslides are attributable to a combination of three factors: a highly weathered bedrock (Cretaceous granodiorite), episodic heavy rainfall, and almost two centuries of intense land-use practices. On average, landslide scars number 140/km 2 in the Cayaguás watershed, equal to 80 landslide scars/km 2 /100 y. The volume of hillslope material eroded by landsliding is estimated at 660,000 m 3 /km 2 (870,000 Mg/km 2). If all colluvium was transported from the catchment, then the volume is equivalent to a mean surface lowering of the entire watershed by 660 mm, or 3.8 mm/y. Soil augering, field observations at construction sites, road cuts and stream banks, mapping from aerial photographs, and GIS-based estimates of the surface area of footslopes, indicate that colluvium may total 149,000 Mg/km 2. If mobilized, this would be sufficient stored material to supply the annual average fluvial sediment yield for as long as 129 years. The great availability of colluvial and alluvial sediment on footslopes, floodplains, and in channels will maintain high sediment yield well into the 21st century in spite of government efforts to reforest hillslopes and institute other hillslope soil conservation measures. Wieczorek, G.F., Preparing a detailed landslide-inventory map for hazard evaluation and reduction, Bulletin of the Association of Engineering Geologists, 21, 337-342, 1984.

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Section: Fluvial Sediment and Runoffmentioning

confidence: 99%

“…Table 4. Annual fluvial sediment discharge and runoff from the Cayaguás watershed, Puerto Rico [Guzmán-Ríos, 1989;Larsen, 1997;Simon and Guzmán-Ríos, 1990;U.S. Geological Survey, 1999).…”

Section: Fluvial Sedimentmentioning

confidence: 99%

Mass wasting and sediment storage in a small montane watershed: An extreme case of anthropogenic disturbance in the humid tropics

Larsen¹,

Román²

2001

Geomorphic Processes and Riverine Habitat

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“…Suspended-sediment data collection on a scheduled basis began in the Lago Loiza basin in 1984 (Guzman-Rios, 1989). The average water year suspended-sediment load from 1984 to 1993 transported at the Rio Grande de Loiza at Caguas gaging station was 271,200 metric tons and 164,400 metric tons at the Rio Gurabo at Gurabo gaging station (table 5).…”

Section: Suspended Sedimentmentioning

confidence: 99%

Effects of land use on upland erosion, sediment transport, and reservoir sedimentation, Lago Loiza basin, Puerto Rico

Gellis¹,

Webb²,

Wolfe³

et al. 1999

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Lago Loiza, the major water-supply reservoir for San Juan, Puerto Rico, has lost 47 percent of its storage capacity to sedimentation since impoundment in 1953. This report describes results of a study on the effects of land use on upland erosion rates, sediment yield, and reservoir sedimentation rates. Based on Cesium-137 and bathymetric survey data, sedimentation rates documented for the period 1964-90 were slightly less than the rates documented for the period 1953-63. The major land use in the early history of the reservoir was cropland, which comprised 48 percent of basin area in 1950. Following economic shifts on the island in the 1960's, agricultural land was abandoned and replaced by forest, which increased from 7.6 percent in 1950 to 20.6 percent of the basin in 1987. The boundary of the Lago Loiza basin is 22 kilometers south-southeast of San Juan. Population in the basin increased 77 percent from 1950 to 1990 and housing units increased 194 percent. Even with the increase of forest cover in the basin, reservoir sedimentation rates did not decrease until 1979-90. This lag time may reflect the transport of sediment that was stored in the fluvial system during the period of deforestation and mobilized during the period of afforestation. In the last 20 years, the substantial increase of population and housing in the basin caused more land area to be disturbed and may have caused sedimentation rates to remain high.

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Suspended-sediment data in the upper Rio Grande De Loiza basin, Puerto Rico

Cited by 2 publications

References 6 publications

Mass wasting and sediment storage in a small montane watershed: An extreme case of anthropogenic disturbance in the humid tropics

Mass wasting and sediment storage in a small montane watershed: An extreme case of anthropogenic disturbance in the humid tropics

Effects of land use on upland erosion, sediment transport, and reservoir sedimentation, Lago Loiza basin, Puerto Rico

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