The effect of development on nitrogen loading on St. John, U.S. Virgin Islands

Abstract

The majority of St. John's land and coast is a National Park and is protected by the federal government. In spite of these restrictions, the population of St. John has risen in the past fifteen years as has the number of tourists that visit the island. A possible side-effect to the growing population is increased nitrogen loading to the bays, which can impact the benthic habitat. The purpose of this thesis is to evaluate the extent of the effects of human developments on nitrogen loading of the bays on St. John, U. S. Virgin Islands. This is accomplished by taking nitrogen samples of the bays, using ArcGIS and the Nitrogen Loading Model to estimate the nitrogen loading of the bays, and correlating historical nitrogen concentrations with increases in population. While the analysis of nitrogen samples of the bays is inconclusive, the Nitrogen Loading Model estimates that bays with greater levels of development have higher amounts of nitrogen loading. Historical nitrogen concentrations show little relationship between the level of development of the watersheds and the concentration of nitrogen within the bays. Overall, there is little evidence that nitrogen loading from development is causing excessive nitrogen loading.