In the late 1960’s, Winter Park citizens began to observe a decline in the water quality of our lakes. The Lakes and Waterways Advisory Board was formed in 1967 in part to develop solutions to the deterioration of our lakes. Stormwater discharges into our lakes were recognized as a major source of pollution, leading to a City ordinance in the late 1970’s requiring on-site stormwater retention ponds for new commercial developments. Later, zoning regulations were modified to require on-site stormwater retention for new and redeveloped residential properties as well. Beginning in 1987 the City of Winter Park began an aggressive program to keep leaves, litter and other large debris out of the lakes. More frequent street sweeping was instituted, especially during the springtime leaf fall season. In addition, about 130 leaf traps were installed over a period of several years on most large stormwater outfalls, which prevent leaves, grass, litter and other large debris from entering the lakes. While it is recognized that these leaf traps did not remove small particles or dissolved pollution in stormwater, they could be installed quickly and cheaply. They exclude tremendous quantities of contamination from the lakes and are making a significant long-term beneficial impact on lake water quality.
In 1989, the City of Winter Park passed a Stormwater Ordinance, which became the centerpiece of the effort for the recovery of our lakes. Perhaps the most important aspect of this ordinance was the establishment of a stormwater utility; a funding mechanism intended to pay for the construction and operation of new lakes cleanup projects. Every residential and commercial property in the City pays a stormwater utility fee, which is related to the amount of impervious (paved) surface area. This fee currently averages about $10 per home per month, which raises Citywide about $2.2 million per year. By direction of the City Commission, 41% of these funds are designated for the construction of new capital projects and the remainder for the operation and maintenance of existing stormwater treatment projects. This funding mechanism is essential to the recovery of our lakes, providing a dedicated funding source that cannot be used for other purposes. Capital projects that have been and will be funded by the stormwater utility are described later in this report.
Project Selection Criteria
Winter Park has been actively planning and constructing stormwater treatment projects since 1989. During that time, the following general priorities have been followed in evaluating and selecting potential projects:
- Treat stormwater inflows to the lakes rather than lake water itself, since pollutant concentrations are higher in stormwater and treatment systems are simpler to install in a confined area, making treatment easier and more cost effective;
- Focus on large stormwater outfall pipes, which are generally the greatest source of pollution;
- Emphasize projects on the Chain of Lakes, which are Winter Park’s largest lakes with public access, the highest visibility, the most extensive recreational use, and the greatest number of lakefront homes;
- Concentrate on the “headwaters” to the Chain of Lakes, especially Lake Virginia, since through normal flow patterns, cleaned-up water from this lake will flow downstream to the rest of the Chain;
- Concentrate on stormwater runoff from commercial areas which typically have a very high percentage of impervious area and proportionally higher pollutant loads.
Over the years, we have adjusted these priorities as conditions have changed and we have learned from experience. As we complete more projects, these priorities will continue to be modified. We have already begun moving toward treating Non-chain Lakes and smaller outfalls. The current five year plan has focuses in part on looking at alternatives to the storm drain traps on most of the small landlocked lakes in the city. Once the majority of the stormwater runoff is treated in some manner, the City may shift focus to projects that treat in-lake pollution: lake water itself and/or lake sediments.
If Winter Park were to be developed from scratch today, significant acreage (as much as 10% of the total land area) would be dedicated to stormwater retention ponds. Unfortunately, stormwater pollution issues were not understood many years ago, and most existing development in the area does not have allowances for stormwater management. With little undeveloped land available, Winter Park often cannot use systems like retention ponds that require large plots of land, forcing us to employ less land intensive technologies, such as alum injection or underground systems. As more experience is gained in the cleanup of urban lakes in Florida and around the United States, promising new technologies will emerge. We will continue to look for new, more efficient and cost-effective systems to improve our lakes.
There are many different technologies available now for treating stormwater pollution before it enters our lakes including the following:
Alum (or other chemical) Injection
Alum is a flocking agent. When injected into stormwater it binds with phosphorus and sediments as it forms a heavier than water floc. The floc then settles to the bottom taking the pollutants out of the water column. Some stations have floc collection systems to remove the floc from the environment.
Traditional Retention or Detention Ponds
Retention ponds hold all stormwater that enters. Water can only leave through percolation or evaporation. Detention ponds slow down water so that sediments can settle out, and algae and bacteria can breakdown other pollutants. Retention/Detention systems retain storms up to a certain volume, and then act as detention systems for volumes above the design amount.
- Exfiltration Systems
Stormwater is allowed to percolate into the ground through large perforated pipes buried beneath the street. Weirs built into the system contain the water to be treated.
- Centrifugal or Vortex Type Water-Solids Separators
Water enters a circular chamber, and must pass through a screen before discharging. The circular motion of the water helps pull sediments to a sump in the center. Smaller and lighter particles are trapped by the screen. The circular action of the water helps clean the screen, and keep the system from clogging.
- Baffle Boxes
Underground chambers with vertical walls, or baffles, that trap sediment as stormwater passes through. Water must build up behind the baffle until it is high enough to flow over. This slows the flow and allows sediments to settle.