49th Street Outfall Treatment Project
If you should have additional questions or concerns please call the City of Gulfport Public Works Department at (727) 893-1089. Additional information on Florida Friendly Landscaping and stormwater ponds is available at the University of Florida/IFAS’s website, www.ifas.ufl.edu or the SWFWMD’s site.
Frequently Asked Questions
No, all small landlocked ponds within the City of Gulfport are actually stormwater detention ponds. The stormwater system is designed and constructed by the City of Gulfport and permitted by the Southwest Florida Water Management District. *(With the exception of those ponds located on Pinellas County School Board properties).
Stormwater ponds are manmade features located in your neighborhood, (Wood Ibis, Tomlinson, Gulfport Elementary, Boca Ciega High School). Detention ponds are often mistaken for small lakes; however, these ponds play a unique role in managing the surface water quality of water ultimately discharged into Boca Ciega Bay. Stormwater ponds play an important role by trapping sediments and other large solids carried by run-off from roads, parking lots, and lawns. In addition to sediments, stormwater ponds also collect a number of pollutants such as bacteria, oils, fertilizers, heavy metals, and organic contaminants,(animal wastes, pesticides, and herbicides. The held brackish water allows heavier contaminants, such as solids or metals, to sink to the bottom of the pond and eventually become bottom layer sediments. The retained water naturally filters the contaminants and returns clean water to nearby water bodies or wetlands.
Nutrients can seep into the water and provide food for unwanted plants like algae. Excessive algal growth can lead to decreased oxygen in the water that fish need to breathe, resulting in fish kills. Bacteria and other pathogens from pet waste can create health hazards in ponds.
By design, the proposed pond in the adjacent to the Marina will and those at Wood Ibis, Tomlinson Park contain a littoral shelf, which is a shallow area within the pond. Regulatory agencies, such as SWFWMD, require that littoral shelves be vegetated to a minimum of 85%. These areas are usually about 1-2 feet in depth and occupy approximately 30% of the entire surface area of the pond. Littoral shelves provide emergent aquatic vegetation the appropriate water depth necessary to thrive. This vegetation competes with algae for space, light and nutrients and helps to filter out pollutants such as heavy metals, oils and fertilizers. An unplanted littoral shelf or one that is sparsely covered by vegetation will regularly make algae blooms worse. In the deeper areas of a pond, water depths deprive algae the benefit of full sunlight; but in an area that is just a few feet deep such as a littoral shelf, the algae have the benefit of full, consistent sunlight. In these shallow areas algae can grow very rapidly. The thicker and denser the littoral vegetation, the less sunlight, living space and nutrients will be available for algae growth. If managed properly, ponds and littoral shelves can provide an aesthetically pleasing and healthy habitat for a wide variety of wildlife; including insects, fish, birds and reptiles.
Much of what some people consider to be weeds are actually beneficial plants. It is the policy of the City not to remove any beneficial shoreline plants. The proper plants will prevent shoreline soil erosion and help to prevent flooding by slowing down the flow of stormwater run- off during major rain events, and provide habitat for select water fowl. Aquatic plants pump oxygen into the water and create habitats by providing cover and nurseries for fish and other organisms. More importantly, vegetated shorelines improve the water quality by filtering polluted runoff and trapping sediments. Additionally, it assists to control the growth of nuisance vegetation and ultimately helps make the pond visually pleasing. Plants grow well when they are fertilized. When excess fertilizers reach stormwater ponds, they provide nutrients necessary for all plants to grow, which leads to an overabundance of plants in your pond. To reduce the amount of plants around your pond, reduce the amount of fertilizer, pet waste, and grass clippings that get into the pond.
What you see is probably algae. Excess nutrients in the water combined with warm, sunny weather, will cause algae to grow very rapidly. This can often lead to excessive algal growth which is commonly referred to as an algae bloom.
Many creatures in the pond use algae as food. Algae is natural and does help break down the nutrients in the pond; however, too much algae may cause problems. Plants need sunlight to grow. When algae cover the surface of the pond, it reduces the amount of light that can get to other plants that live in the water, or on the bottom of the pond. This can prevent many of the native plants from growing and reduce the viability of the pond ecosystem.
Submersed vegetation is various aquatic plants growing below the water’s surface. While these plants will help filter out pollutants and provide a habitat for aquatic life, non-native or nuisance weeds need to be controlled. It is necessary to control submersed vegetation to prevent invasive species from taking over. Additionally, when allowed to reach the surface often mats of algae will often develop in these areas causing new problems.
We use several different options to help control algae blooms and submersed vegetation. Sometimes it is necessary to use chemicals, such as aquatic herbicides, to treat either of these, for this we contract with a certified lake maintenance contractor. For some ponds we use biological and/or mechanical methods, such various aeration devices (fountains) or beneficial bacteria and microbes. However, the best method is educating the community on how to help prevent nutrients, such as fertilizers from ever entering the ponds by following the University of Florida/IFAS Florida Yards and Neighborhoods recommendations for Florida Friendly Yards. www.ifas.ufl.edu
Aeration exposes water to air, where it absorbs oxygen. In a healthy pond, when plants and fish die off, their remains fall to the bottom, and beneficial bacteria break down the waste. But algae forms when oxygen levels decline, coating the water’s surface and denying plants and fish the oxygen and sunlight needed for survival. Aeration uses the power of water, air or machinery to force both oxygen-depleted water and waste to the pond’s surface, where gases are released and oxygen is absorbed. Thus, allowing beneficial bacteria to thrive, while depleting algae’s food source. When algae disappear, fish and plant life can flourish. However, with City budget constraints, combined with the initial cost to purchase, install these aeration devices, the number that can be installed each year is limited.
Stormwater pond environments rely on natural processes to maintain natural order. Proper water quality is achieved through the activity of naturally occurring microorganisms. Today, most ponds are bombarded with excess nutrients from multiple sources including stormwater runoff, fertilizers, animal waste, and pollution. The naturally occurring bacteria cannot keep up with this influx of nutrients. The microbial species occur naturally in most ponds. Although specialized, they have trouble maintaining large populations, and are easily pushed out by other bacteria that do not perform the same beneficial processes. By supplementing the natural biological processes, it is possible to maintain very large populations of microbes that constantly “graze” on excess nutrients and organic sludge.
A few dead fish floating on the surface is not necessarily cause for alarm. The majority of fish kills that occur are due to a variety of natural causes. Fish can die of starvation, injury, stress, disease, parasites, lack of dissolved oxygen in the water, changes in the pH, and even rapid fluctuations in temperature. Low dissolved oxygen levels are the most common cause of fish kills. The amount of oxygen in a body of water will vary with water temperature, aquatic plant densities and amount of sunlight. During the rainy seasons, stormwater runoff can lead to fish kills. Heavy rains wash organic material, nutrients, and fertilizers into the ponds, – accelerating plant growth which can lead to depleted oxygen levels. These same rain events also carry herbicides, pesticides and pet waste into stormwater ponds. Ammonia, which comes from animal waste, is highly toxic to fish.
The man-made concrete structure that you see is an outfall structure. An outfall structure is the discharge point for the stormwater pond that prevents the pond from overflowing during heavy rain events.
No, you do not fill stormwater ponds. While everyone wants their pond to look aesthetically pleasing, these ponds were designed as part of a storm water system by managing the runoff from rainfall. A stormwater pond is specifically designed to help prevent flooding and remove pollutants from the water. Adding water to a pond can cause flooding by interfering with the pond’s design and ability to hold stormwater runoff.
The bad odor you notice typically comes from one of these three sources: rotting organic matter, water turnover or certain types of algae. Ponds with stagnant, poorly oxygenated water develop into temperature layers. Decaying organic matter settles on the bottom of the pond where there is little oxygen thus slowing the break down process and producing odor. Windy cooler weather or heavy rainstorms can cause a pond to mix, which brings the bad water to the surface. This most commonly occurs right after our first cold front but can also occur throughout the warmer months of summer and fall. Finally, certain kinds of algae such as cyanobacteria or chara algae can emit a musty, earthy odor. The use of an aeration device in the pond helps target the cause of these odors by continually mixing and oxygenating all levels of the water column and promoting the growth of beneficial bacteria.
The City of Gulfport is responsible for managing and maintaining the City’s stormwater ponds. Regardless of who has the responsibility for maintenance, all of the residents iof the City of Gulfport can help keep ponds clean, and healthy. This will reduce the amount of maintenance by limiting the amount of nutrients and pollutants in stormwater runoff.
SWFWMD GRANT $640,291
CITY OF GULFPORT $640,291
TOTAL COST $1,780,582
- The wet pond and baffle boxes will remove 2,320 pounds of pollution from Boca Ciega Bay
- The wet ponds will capture one inch of stormwater runoff with most of the debris
- Eighty percent of the flow will be discharged 2,670 feet further away from the beach
- The additional baffle boxes will remove debris at the intersections of 27th Ave. and 48th St. and 49th St. S. and 29th Ave. S. to improve Boca Ciega Bay
- The alum project removed an additional 489 kg of nutrients at approximate cost of $1,250,000 more than the wet ponds. At this project location, the alum ponds are not cost efficient and constructing and maintaining them is not feasible
- SWFWMD and FDEP agree that this project will improve Boca Ciega Bay water quality and have a contracts with City for their matching contribution.
49th STREET / PROJECT SCHEDULE
- Existing Southwest Florida Water Management District (SWFWMD) permit extension July 2014
- Cooperative Funding application to Southwest Florida Water Management District (SWFWMD) October 2014 – Funding in October 2015
- Construction January 2016-June 2017
- Ongoing System Maintenance – Starting June 2017
Gulfport’s Public Works Superintendent Don Sopak watches as a six-foot diameter section of existing stormwater pipe is removed beneath 49th Street and a 3,200-pound pre-cast concrete diverter is lowered into place as a final leg of the 49th Street Outfall Treatment Project. The diverter will channel stormwater to detention ponds adjacent to the Gulfport Marina for filtration prior to being discharged into Boca Ciega Bay and is expected to remove thousands of pounds of pollution from the Bay. The project is scheduled to be completed this summer 2017.
image/info credit: Wolfgang Deininger
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