Reefs Affected by Storm Water Run-off

Letter to the Editor:

I’d like to add an important element to a recent Associated Press article about the Coral Reef Task Force Meeting in St. Thomas. Quoting from that article:

“What causes disease in coral can be hard to pinpoint and could be a combination of things. Other threats include silt runoff from construction sites, which prevents the coral from getting enough sunlight, and a record increase in fleshy, green algae, which competes with coral for sunlight.”

This list of issues, probably inadvertently excludes the most important source of sediment in conditions such as we find in the U.S. Virgin Islands, and other areas of the northeastern Caribbean. Based on more than a decade of research by students and graduates of the Department of Geology of Colorado State University, mostly in the Fish Bay watershed and other areas on St. John, and jointly sponsored over the years by a variety of territorial, UVI, federal and private resources, Island Resources Foundation concludes that the single most significant cause of erosion and sediment in near coastal waters is dirt roads and driveways usually built by the private homes and sub-divisions in all of our coastal areas. Especially dangerous in this regard are roads that are frequently graded in an attempt to keep a smooth surface. (See for example the large sediment discharge photographed in Haulover Bay in 1999 at

Dr. Carlos Ramos-Scharron (who has studied these issues in the Virgin Islands for many years, but who has nothing to do with the web page cited above) is currently organizing a new project with the residents of the Fish Bay watershed in St. John to improve the ability of GIS models to predict sediment-prone road segments and to use those models to predict the most effective and efficient mitigation strategies.

Bruce Potter
Island Resources Foundation