Department of Geography and the Environment

Runoff and Soil Erosion Study Gets Underway in Culebra, Puerto Rico

Fri, August 18, 2017
Runoff and Soil Erosion Study Gets Underway in Culebra, Puerto Rico
Banderote Reef, at Tamarindo Bay, Culebra Alfredo Montanez, 2012

Some of the most pristine coral reef ecosystems in the Caribbean lie off the small island of Culebra, located 20 miles east of Puerto Rico’s mainland.  However, since the 1990s, Culebra has experienced a significant increase in land development and unpaved roads, which are key contributors to sediment runoff into nearby coastal waters.  Sediments entering the bays and estuaries inhibit the health of the surrounding corals by reducing their exposure to sunlight and burying the coral when the sediment settles.  Due to the environmental and economic importance of these coral reefs, recent efforts have been made by NOAA, The University of Puerto Rico, and NGOs such as Protectores de Cuencas to aid in protecting these ecosystems from further damage.

During the month of July, incoming master’s student Preston McLaughlin, Professor Carlos Ramos-Scharrón from the Department of Geography and the Environment, and Yasiel Figueroa from the Department of Environmental Sciences at the Universidad de Puerto Rico Río Piedras relied on various research techniques to help quantify the amount of runoff and sediment being produced from unpaved roads in Culebra, while also evaluating the efficiency of previously applied erosion control techniques.  Methods used to gather the data for this project included rainfall simulations, which measured runoff and erosion rates from unpaved roads and natural areas in a controlled environment, and Guelph Permeameter readings to determine water absorption rates for both natural soils and unpaved roads.  Accompanying the data collected from these simulations, there are also various instruments installed around Culebra that will be used to monitor the intensity and sediment runoff yields for future rainfall events.  The data collected from these natural rainfall events will provide important information regarding sediment erosion rates at a larger scale.  The information derived from these research techniques are intended to help influence decision-making practices from organizations focused on preserving the health of coral reef ecosystems, and effectively maintaining unpaved roads. 

The data gathered and analyzed from this project will be used as Preston’s master’s thesis. For any further questions or information, please contact Preston at, or Carlos at

Rainfall simulation on an unpaved road segment








Carlos and Yasiel taking readings from a rainfall simulation in a natural area






Preston taking readings from the Guelph Permeameter

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