Center for Coastal Resources Management

The objective of this project was to perform a combination of water quality modeling analyses that evaluated individual systems for general flushing characteristics. Residence times for water bodies in the Virginia coastal zone were calculated using three water quality models, depending upon the complexity of the water body. Results showed that residence times range from 0.1 to 29 days. One outlier has a residence time of 72 days. Approximately 80% of water bodies in the Virginia coastal zone are dominated by quickly flushed tidal creeks and tributaries with residence times less than about 5 days.

Descriptive statistics were used to analyze the data, and the residence times were grouped into tidal flushing categories using mean depth. Shallower water bodies flush more quickly than deeper water bodies. The flushing categories (quickly, intermediately, and slowly flushed) reflect a relative time frame in which a water body is flushed. Residence times and flushing categories were joined to a geographic information system layer in order to spatially display and analyze results.