Jones Edmunds developed a Watershed Management Plan (WMP) for the Coastal Fringe Roberts Bay (North) Watershed. The project generally followed SWFWMD’s Guidelines and Specifications for Developing Watershed Management Plans, with the four major elements being Project Development, Digital Topographic Information, Watershed Evaluation, and Watershed Management Plan. The watershed is approximately 5 square miles and includes the coastal regions east of the Phillippi Creek and Matheny Creek watersheds. Most of the development occurred before modern stormwater management regulations, so only a small percentage is served by current Best Management Practices (BMPs). Approximately three-fourths of the watershed is below the 100-year storm surge.
With the exception of Grand Canal, which is primarily for watercraft navigation, there are very few larger stormwater management systems in the watershed. Much of the watershed is characterized by local-scale drainage features that discharge directly to the Gulf of Mexico or the Bay. Therefore, the level of detail in the model and the determination of what should be represented in the watershed modeled differed from other Sarasota County and SWFWMD WMPs.
Digital topographic information was primarily based on 2007 LiDAR data from the Florida Division of Emergency Management Coastal LiDAR project, which Jones Edmunds helped to manage. Due to existing level of urbanization, virtually no topographic voids due to development are newer than the LiDAR flight. However, the density of multi-story buildings in some portions of the watershed does leave a questionable bare-earth representation of the terrain.
The watershed evaluation was expedited using the County’s Stormwater Infrastructure Database. This database, although not complete, allowed for a detailed understanding of the local storm sewer networks and their impact on basin delineations. Additionally, they provided a more thorough understanding of the stormwater system at the initial desktop level than what is often available, which helped focus the amount of field reconnaissance needed.