Land-Use Effects on Erosion, Sediment Yields, and Reservoir Sedimentation: A Case Study in the Lago Loíza Basin, Puerto Rico

Potential Effects of Runoff, Fluvial Sediment, and Nutrient Discharges on the Coral Reefs of Puerto Rico

“…Once offshore, the sediment is reworked and redistributed by waves and currents. During the water years 1984 to 1993, 80% of the annual suspended-sediment load was transported into Lago Loíza in 4 to 24 days from the Rio Gurabo branch and in 7 to 12 days from the Río Grande de Loíza branch (GELLIS et al, 2006). Average sediment concentrations in slopewash measured by GELLIS et al (2006) ranged from 2000 ppm from forested areas to more than 60,000 ppm for waters flowing across bare ground at construction sites.…”

“…During the water years 1984 to 1993, 80% of the annual suspended-sediment load was transported into Lago Loíza in 4 to 24 days from the Rio Gurabo branch and in 7 to 12 days from the Río Grande de Loíza branch (GELLIS et al, 2006). Average sediment concentrations in slopewash measured by GELLIS et al (2006) ranged from 2000 ppm from forested areas to more than 60,000 ppm for waters flowing across bare ground at construction sites. In comparison, the average annual discharge-weighted sediment concentration was only 270 ppm from the Río Bairoa, a watershed with 6% pasture and forest (GELLIS et al, 2006).…”

“…Average sediment concentrations in slopewash measured by GELLIS et al (2006) ranged from 2000 ppm from forested areas to more than 60,000 ppm for waters flowing across bare ground at construction sites. In comparison, the average annual discharge-weighted sediment concentration was only 270 ppm from the Río Bairoa, a watershed with 6% pasture and forest (GELLIS et al, 2006). CRUISE and MILLER (1994) Calvesbert, 1970) and (B) cumulative precipitation associated with Hurricane Georges, September 21-22, 1998 (modified from U.S. Geological Survey, 1999).…”

A review of radiometric analysis on soil erosion and deposition studies in Africa

“…The 137 Cs isotope has a half-life of about 30 years (Poręba, 2006). Gellis et al (2006), Walling (1998), Mahawatte and Abeynayake (2010) observed that there is a strong adsorption of 137 Cs by clay and organic matter in soils. According to Patrocinio and Andrello (2009) and Dercon et al (2012) 137 Cs is useful in studying the sediment chronology since it is rapidly and strongly absorbed to fine particles of the soil.…”

Long-Term Impacts of Non-Sustainable Tourism and Urban Development in Small Tropical Islands Coastal Habitats in a Changing Climate: Lessons Learned from Puerto Rico

“…Land clearing trends in support of the little remaining agriculture on the island and construction associated to urban sprawl and tourism stand out as some of the most important active sources of terrestrial sediment on the island. It is important to note that empirical research shows that while agricultural activities may induce a tenfold increase in hillslope-scale erosion rates relative to undisturbed conditions www.intechopen.com (Gellis et al, 2006;Smith & Abruña, 1955), erosion rates on barren surfaces typical of construction sites and unpaved roads may represent a one to a four-order magnitude increase relative to background rates (Gellis et al, 2006;Ramos-Scharrón, 2010). Therefore, the combination of a very high road density network that increases the incidence of landslides accompanied by a fast pace of land transformation to urban spaces suggests that current sediment yield rates may be among the highest ever experienced on the island.…”