Simply put, a stormwater system is a tool for managing the runoff from rainfall. When rainwater lands on rooftops, parking lots, streets, driveways & other surfaces that water cannot go through, the runoff (called stormwater runoff) flows into grates, swales or ditches located around your neighborhood. These send the water into your stormwater pond. A storm water pond is specifically designed to help prevent flooding & remove pollutants from the water before it can drain into the ground water, our main source of drinking water, or into streams, rivers, lakes, wetlands, estuaries or the gulf. Your storm water pond might be located in your backyard, down the street or on nearby property. Without a stormwater system, the stormwater runoff usually flows into the nearest water body without treatment. The runoff carries pollutants such as litter, motor oil, gasoline, fertilizers, pesticides, pet wastes, sediments & anything else that can float, dissolve or be swept away by moving water.
Wetlands are Florida’s original storm water systems & once covered more than half the state. Wetlands are extremely valuable resources because they:
• Control flooding. They do this by soaking up & retaining excess water like a giant sponge. They also slow down water flow, giving floodwaters more time to recede.
• Serve as habitat for a variety of plants & animals. Many endangered plant & animal species depend on wetlands for their survival.
• Improve water quality. Wetlands slow down the flow of water & absorb pollutants, storing them, breaking them down & in some cases even using them as nutrients.
Unfortunately, because people once misunderstood the true value of wetlands, more than one-half of our original wetlands have been drained for agriculture or filled for roads, housing developments & industrial complexes. As development increased & more paved areas covered the land, storm water runoff became the primary source of pollution to surface waters in Florida. In the early 1980s, the Florida Legislature passed laws requiring treatment of storm water.
Stormwater systems come in a variety of shapes, sizes & forms, but basically there are two types, retention & detention.
A retention system is designed to allow water to seep through soil into the shallow groundwater aquifer. A system can be constructed or it can be a natural depression. Grass stabilizes basin slopes & filters sediments. Retention systems are constructed so that storm water percolates into the ground without direct discharge to natural surface water bodies. A swale is a linear retention system. It is either a constructed or natural area shaped to allow water to be quickly absorbed into the ground or to allow the water to flow to other water bodies. As in a shallow ditch, a swale promotes water absorption through soils. Swales hold water during & immediately after a storm, but they are generally dry.
Detention systems (ponds) are the most recognizable stormwater system. They are designed to allow material to settle & be absorbed. After a storm, water slowly drains from the pond through a pipe in the “outflow” structure. Part of the pond, known as the permanent pool, is always below the level of the drain structure. Constructed detention systems (ponds) are required to have aquatic plants around the perimeter to help filter sediment in storm water runoff. The owner of the pond should refer to the permit for exact specifications. Because retention & detention systems were designed to imitate natural processes, individuals may have stormwater systems on or near their property without realizing it. What appears to be a natural indentation in the backyard may have been designed as a stormwater swale. What looks like a wild patch of shrubbery may be an important vegetative buffer around a pond.
In Florida, the responsibility for permitting most stormwater systems rests with the water management districts. After developers complete construction of permitted systems in residential areas, the permit & the legal responsibility for maintaining these systems are typically passed on to a homeowners, condominium owners, or property owners association. It is then that the upkeep & maintenance of the system becomes the responsibility of the association, not the developers or the water management district. The association is responsible for labor & expenses for keeping the system functional. This responsibility applies to every homeowner & property owner in the neighborhood, even if they do not live adjacent to a detention or retention system, as everyone’s stormwater flows into the system. Copies of your association’s operation &maintenance permit, plans, & maintenance guidelines were provided at the time of the transfer to your association’s representative. For more specific information about your pond, you may call the Southwest Florida Water Management District’s stormwater permitting staff. Click on the following link to obtain the contact information for the SWFWMDs service offices.
You can help conserve and improve the quality of water that enters the storm water ponds & promote a healthy environment within your community by following the advice provided below.
If properly maintained, storm water ponds help prevent flooding & filter out pollutants before they reach streams, rivers, lakes, wetlands, ground water, estuaries &, ultimately, the gulf. Following are a few basic maintenance guidelines that can help keep your stormwater system functioning properly:
• Clear or clean inflow/outflow structures.
• Remove nuisance and excess vegetation.
• Repair eroded slopes.
• Clean up trash & yard waste in your yard & gutters & around storm drains.
• Apply Florida-Friendly Landscaping™ principles to your landscape, which can conserve water & reduce pollution of water resources. By knowing your plants, soils, & water needs, you can dramatically reduce the amount of water used for irrigation, chemicals used for pest control & fertilizers used for growth. Information on Florida-friendly landscaping can be found on the District’s web site, http://www.swfwmd.state.fl.us/yards/ , or on the University of Florida’s web site,http://www.floridayards.org/.
• Plant trees around the perimeter of a stormwater pond to help shade the area, absorb nutrients & lower the water table.
• Plant a buffer zone (minimum of ten feet) of low-maintenance plants between your lawn & shoreline to absorb nutrients & provide wildlife habitat.
• Use nontoxic chemical alternatives whenever possible & pull weeds by hand.
• Avoid overuse of fertilizers, especially near the water’s edge. Rain & lawn watering can wash excess fertilizer into water bodies where excess nutrients cause algal blooms (green pond scum) & undesirable weed growth. The University of Florida’s Institute of Food & Agricultural Sciences recommends using fertilizers with a high percentage of slow release nitrogen. The higher percentage of slow-release, the less chance of leaching into Florida’s water bodies. Proper fertilizer application can result in less mowing, less thatch buildup, less irrigation, fewer nutrients washing into ponds & water bodies, & fewer insect & disease problems.
• Use only herbicides labeled for aquatic use when maintaining stormwater ponds. Herbicides not labeled for aquatic use may harm fish & other aquatic life, & their Application to aquatic sites is prohibited by state & federal law.
• Wait until grass is actively growing to apply fertilizer. Fertilizer applied when grass is not growing wastes your money & time & can contaminate your water. If fertilizer is spilled on the lawn or on the sidewalk or pavement, sweep it up as thoroughly as possible & put it back in the bag.
• Never dump oils & other chemicals from your home directly into stormwater drains, which are direct conduits to your stormwater pond or natural water body. Contact your local government’s waste management department for a list of disposal facilities.
• Keep vehicles tuned up & in good operating condition. Check for drips & repair leaks immediately to keep nuisance oils off pavement.
• Buy low or no-phosphate cleaners & detergents. Phosphates act as a fertilizer & increase algae & aquatic weeds in stormwater ponds. When these plants die, they rob the water of oxygen & fish may die.
• Wash your vehicles, bicycles & home equipment on the lawn, where soapy water can’t quickly run toward the nearest storm drain, picking up other pollutants as it goes. Wash your car with nontoxic, low-phosphate soap & use water sparingly.
• Sweep walks & driveways instead of hosing them down.
• Clean up pet wastes from which nutrients & bacteria can enter the stormwater drains & contaminate the water system.
• Avoid cutting your lawn too short, which reduces its effectiveness in capturing runoff. Leaving it taller will help it to survive dry periods.
• Never deposit lawn clippings in water bodies & storm drains as this can increase oxygen demand in the water, which can significantly harm fish populations. Use lawn clippings for mulch or compost.
• Do not fill stormwater ponds, swales, & retention systems because this can cause flooding & endanger water bodies. Stormwater systems are designed & constructed to an appropriate size. Any reduction in treatment volume will interfere with the pond’s ability to hold stormwater runoff.
• Changing the elevation of large pieces of property can have drastic impacts on where stormwater flows. Consult the stipulations of your neighborhood’s permit before any construction.
Above Information taken from SWFWMDs website on 2-17-015 from the following link:
http://www.swfwmd.state.fl.us/files/database/site_file_sets/33/stormwater_systems.pdf
If you have any questions, would like an aerial of your site, need a proposal, or would like to hire Zoller Engineering to quickly recertify your Stormwater Management System, please text or call 941-812-2585, or email Bryan.Zoller@gmail.com.
Florida P.E. # 63933