Is the quality of water in the Big River Management Area affected by land use?
An ecological risk assessment of the Big River Management Area

Aaron Wdowin

Brown University, Sc.B. May 2005

The Big River Management Area is fast becoming a topic of interest as the water demand in southern Rhode Island increases. Due to its location, hydrogeologic properties and large amount of relatively pure water, the development of this area is viewed as the next step in providing municipal water supplies to the state. There is currently an absence of effective management if this area is to be developed into a water supply. To address this, management will require scientific studies that determine the relationship and flow dynamics of the ground and surface waters within the entire watershed. This study attempts to answer the question of whether contaminants from various potential sources are adversely affecting the surface waters; as well as to encourage the creation of a framework that identifies threats to the aquifer to better the overall system of management. Stream samples were collected from November through March to compare the stream ion concentrations when roads were salted versus when they were unsalted. The samples were analyzed with an ion chromatograph to detect the presence of Na and Cl, which were used to identify if storm runoff was affecting surface water chemistry.

It was found that highway runoff is reaching the stream and therefore should be a concern for future management as any contaminant spilled is likely to contaminate the aquifer. The dairy farm located in the BRMA does not seem to threaten the water of the aquifer because the natural system can currently dissipate low concentrations of nitrate contaminants. As expected there was a strong correlation between stream contaminant concentration and increased precipitation for all of the potential contaminant areas. This study has begun the process of locating sources of surface water contamination within the BRMA, and providing management with scientific data that will aid in the protection of the aquifer now and in the future.