The Stormwater Ecological Enhancement Project (SEEP) began in 1995 as a take-home final exam for the course Ecosystems of Florida. The objective was to develop a management plan to enhance a stormwater retention basin located within the University of Florida Natural Area and Teaching Lab (NATL) for species diversity while optimizing the basin's use for research and education. Since that time, the Wetlands Club at UF has taken this project further and implemented a full-scale created wetland that achieves not only the original objectives but also improves wildlife habitat, water quality, and aesthetics. These efforts have been in close coordination with the NATL Advisory Committee.
What is a Stormwater Retention Basin?
Water that runs off the land during and after a rainstorm is called stormwater runoff. This runoff and any pollutants it carries flows into streams, rivers, lakes and depressions throughout the landscape. In an urbanized landscape natural physical, chemical and biological processes are disrupted and leaves, litter, animal waste, oil, greases, heavy metals, fertilizers and pesticides are transported downstream. A stormwater retention basin provides temporary storage for the runoff generated by development in the watershed, releasing it slowly and reducing the potential for flooding. The basin also provides some treatment of pollution carried by the stormwater runoff.
While wetlands have historically been considered of little importance, our increasing understanding of these systems is changing this misconception. Wetlands are now recognized for providing many vital benefits. Some of these benefits include:
- habitat for commercially valuable fish and shellfish,
- improved water quality.
Although we have lost more than 50 percent of the historic wetlands in the lower 48 states, protection of wetlands has increased considerably over the past 15 years due to recognition of these values.
Wetlands and Stormwater Basins
Wetlands can be found alongside rivers and lake shores, and as low areas in the landscape that often become flooded during storms. These wetlands are the natural stormwater basins of the landscape. As humans create stormwater basins to reduce the effects of development, it seems only logical to mimic these natural stormwater basins. This provides benefits beyond that of water storage as the basin becomes a multipurpose area serving our needs to reduce flooding while offsetting wetland functions that have been lost over the past 200 years. The water treatment component of the retention basin would also be substantially enhanced by the diversity of vegetation and complexity of the integrated wetland community. The integration of these "free" services provided by a natural system with the needs of our growing world has been termed Ecological Engineering. This new approach to urban and regional planning is not only a more environmentally sensitive approach, but one that uses processes that have been working naturally for millions of years.
The Retention Pond at NATL
The 3-acre retention pond is the low point of a 39.75 acre watershed. The majority of the basin was constructed in 1988 with additional storage created in 1990. Structures within this watershed contributing significant runoff to the basin include the Center for Performing Arts, Entomology and Nematology buildings, the Park & Ride commuter lot and roadways between and around these buildings. The total storage of the basin to offset the increased runoff generated by these impervious surfaces is 478,000 cubic feet. As originally designed the bottom of the basin is essentially flat, with uniform slopes on the north, south and east sides. To the west of the basin the slope is low and quickly grades into the preexisting depression of the area. Because the basin is almost uniform in elevation the established vegetation was dominated by Cattail.
Ecologically Enhanced Design
The primary goal of the project is to increase the diversity of flooding depths and frequency of flooding that will occur since this is the primary factor regulating species composition in a wetland. To do this two depressions, one 4-feet, the other 5-feet deep, were dug at the southeastern end of the pond providing a deep, open-water habitat. At the north end a low berm was constructed to temporarily impound 80% of the entering stormwater. This forebay provides the first phase of treatment and was planted with species known to take up heavy metals and remove nutrients. Water from the forebay is then slowly released, first flowing through an area planted to resemble a bottom-land hardwood swamp, and move into a shallow freshwater marsh before entering the deep-water ponds.
At the southeastern end of the pond another small berm was built to divert stormwater away from the deep-water ponds, increasing treatment time. At the end of this berm a knoll was built and planted with trees to provide nesting or roosting sites for birds. The basin was planted with species that resemble those found in wetlands of North Central Florida. A boardwalk also will be constructed.
Expected SEEP Benefits
The SEEP project already has provided a great learning experience for Wetlands Club members through project design and organization, regulatory agency interaction and team work. Other benefits of the project include:
-Species diversity. The variety of plantings and topographic diversity on the sight provides new genetic material as well as suitable establishment sites for long-term increases in vegetative species diversity within the basin.
- Wildlife habitat. Vegetative diversity as well as diversity of aquatic habitat provides a multitude of new biotic niches not previously available in the basin. The value of this habitat becomes increasingly important as other areas on campus and in the Gainesville community are encroached upon.
-Aesthetics. Retention basins are notoriously unattractive, often fenced in, littered with trash, and square. Although the retention basin at the NATL is pleasant compared to some, its appeal would be improved if it resembled a diverse wetland.
-Water Quality. Construction of the forebay, planting of species known to have high treatment potential, and diversion of stormwater to maximize treatment all improve the water treatment potential of the basin.
-Research. Since integration of wetlands and stormwater basins is still a relatively new concept, little is known about optimization and performance of these systems. Implementing SEEP provides a unique opportunity to test the principles of this integration, pushing the University of Florida to the forefront of this technology. The location of this site on campus as well as the location of the site within NATL allows for easy access and control over activities within the site. Faculty, staff and state agencies interested in this topic will be able to use this as a long-term study site.
-Education. Educational opportunities for both students and the public enormous for this site. The University has one of only three wetland centers in the country with some of the founding faculty in principles of Ecological Engineering. Many courses throughout the campus use the area for various components of their curriculum. Public education opportunities abound with the construction of the new Florida Museum of Natural History within a stones throw of the basin.