Lake Apopka facts for kids
Quick facts for kids Lake Apopka |
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 Lake Apopka
Location in Florida
Lake Apopka
Location in the United States
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| Location | Orange / Lake counties, Florida, United States |
| Coordinates | 28°37′14″N 81°37′19″W / 28.62056°N 81.62194°W |
| Basin countries | United States |
| Max. length | 12.3 mi (19.8 km) |
| Max. width | 9.7 mi (15.6 km) |
| Surface area | 30,800 acres (125 km2) |
| Average depth | 15.4 feet (4.7 m) |
Lake Apopka is the fourth largest lake in the U.S. state of Florida. It is located about 15 miles (24 km) northwest of Orlando. Most of the lake is in Orange County, but part of its western side is in Lake County.
Lake Apopka gets its water from a natural spring, rainfall, and stormwater runoff. Water from Lake Apopka then flows through the Apopka-Beauclair Canal. It empties into nearby Lakes Beauclair and Dora. From Lake Dora, the water continues to Lake Eustis, then to Lake Griffin. Finally, it flows northward into the Ocklawaha River, which eventually joins the St. Johns River.
Contents
Lake Apopka's Story
For many years, Lake Apopka was a very popular spot in Central Florida. In the 1940s, people from all over the United States came to fish for large bass. There were 21 fishing camps along the lake's edge!
However, people have changed Lake Apopka for over 100 years. In 1888, the Apopka-Beauclair Canal was built. Then, in 1941, a wall called a levee was built. This levee helped drain 20,000 acres (80 square kilometers) of shallow marshland so it could be used for farming.
When farms and other places released water full of nutrients into the lake, it caused big problems. These nutrients made too much algae grow. This "algal bloom" made the lake cloudy and unhealthy. It also caused the lake to lose its fun activities and its large fish populations.
In 1980, a company called Tower Chemical Company (TCC) improperly got rid of harmful chemicals, including a pesticide called DDE. These chemicals spilled into Lake Apopka. The U.S. Environmental Protection Agency (EPA) was told about the spill, and TCC stopped its operations in December 1980.
The EPA started an investigation in 1981. The site was cleaned up and became a Superfund site. Even with these efforts, some chemicals soaked into Florida's underground water supply, called an aquifer. These chemicals spread to other lakes and waterways in Central Florida. They caused health problems for many animals in the lake, including alligators, affecting their ability to have babies.
In 1991, a group called Friends of Lake Apopka (FOLA) was formed. Their goal was to help the lake recover from the farms that were releasing a lot of phosphorus into it. Farmers used lake water to flood their fields in summer to stop soil from washing away. Then, they would pump this water, full of phosphorus, back into the lake before planting. This made the lake very unhealthy, causing huge algal blooms. These blooms took away oxygen and sunlight, which plants on the lake bottom needed to live. Over many years, the lake's sandy bottom became covered in a thick layer of muck.
In 1996, Governor Lawton Chiles signed the Lake Apopka Restoration Act. This law provided money to buy the farmlands that were causing the pollution. When the farms closed, the St. Johns River Water Management District (SJRWMD) could start turning the fields back into the marshland they once were. They checked the land for chemical pollution and began cleaning it up.
North Shore Restoration Efforts
Historically, over 85% of the phosphorus entering Lake Apopka came from farms on its north shore. To fix this, the District and the U.S. Department of Agriculture (USDA) bought almost all these farms between 1988 and 2001. This greatly reduced the amount of harmful nutrients flowing from farms into the lake.
The 1996 Lake Apopka Improvement and Management Act set a goal for how much phosphorus should be in the lake. The District aimed to reduce phosphorus from farming by 75% compared to 1989–1994 levels. The ultimate goal is to have only 55 parts per billion (ppb) of phosphorus in the lake.
Restoring the wetlands on the North Shore Enhancement Area (NSEA) helps reduce stormwater pollution and nutrient levels in Lake Apopka. This speeds up the lake's recovery. The restoration plan involves building new structures, and using special methods to treat the soil.
One method is called "soil inversion." This process uses special farm equipment to plow up to one meter deep. It essentially flips the soil, bringing clean soil to the surface and burying the contaminated top layer. This top layer contained high levels of organochlorine pesticides (OCPs) from years of farming. This work was finished in May 2009. It helped make sure these harmful chemicals could not enter the food chain. The inversion process made about 4,000 acres (1,600 hectares) of soil safe.
The soils in the NSEA also had too many nutrients like phosphorus because of years of farming. To help with this, a "soil amendment" was added. This is a leftover material from drinking water treatment. It helps trap extra phosphorus in the soil. This stops phosphorus from getting into the water when the area is reflooded. This soil amendment was put on about 7,000 acres (2,800 hectares) and was mostly done by 2009.
As each part of the restoration is completed, experts check the area to make sure it's safe for wildlife. Once approved, the areas are reflooded to become wetlands again. The new structures help create different water levels for various wetland habitats. They also allow water to be moved between different areas within the NSEA, reducing the need to release water into the lake.
When new areas are flooded and animals start to move in, fish are regularly checked. This ensures that pesticide levels in their bodies are safe for birds that eat fish. Newly flooded areas are watched for at least a year to make sure no pesticides build up in the food web that could harm water birds. Also, weekly bird surveys are done to quickly spot any problems. By January 2011, almost 10,000 acres (4,000 hectares) were in different stages of reflooding.
On February 20, 2014, the Lake Apopka Loop Trail opened to the public. This trail goes through the NSEA, allowing people to enjoy the restored area.
The Marsh Flow-Way
The Marsh Flow-Way is a special wetland built by people. It is located on the northwest shore of Lake Apopka. It started working in November 2003. Its main goal is to remove phosphorus and other floating materials already in Lake Apopka's water.
This system covers about 760 acres (308 hectares). It has four separate wetland areas, along with walls, canals, and ditches. The Marsh Flow-Way treats water that is pumped into it from Lake Apopka. This lake water has too much phosphorus, algae, and floating bits.
Water flows from west to east through the system. Gates and boards control the water level in each wetland area. Cleaned water from all areas collects in a pump basin. From there, it is pumped into the Apopka Beauclair Canal. Most of this cleaner water goes back into Lake Apopka. The rest flows downstream to another facility that removes nutrients.
The main plants growing in the flow-way are shallow marsh and shrub swamp plants. Shallow marsh plants include pickerelweed, arrowhead, and cattail. Shrub swamp plants include primrose willow and some types of willow. There are also open water areas in the wetlands.
As lake water moves through the plants in the Marsh Flow-Way, it slows down. This allows tiny particles, which contain phosphorus and other nutrients, to settle out of the water. These settled particles, along with decayed wetland plants, form new layers of organic material over the native soils. Water usually stays in the wetland areas for two to seven days. The water depth can be between 12 and 18 inches (30 to 45 cm).
The flow-way's performance changes with the seasons. It works best in cooler months (October through May) and less well in warm months (June through September). Over seven years of operation, it has performed as expected. By 2010, the system removed about 28% of the incoming phosphorus each year. It also removed about 90% of the incoming floating solids.
Harvesting Gizzard Shad
One way to help Lake Apopka is by removing gizzard shad fish. These fish contain phosphorus in their bodies. By taking them out of the lake, we remove that phosphorus. This also helps reduce how much phosphorus is recycled within the lake. When there is less phosphorus, there are fewer algae, which makes the water clearer.
Removing gizzard shad from other lakes has helped improve the food web, reduce algae, make water clearer, and create better conditions for game fish. This method is expected to have similar good results in Lake Apopka.
By the fall of 2011, about 18.5 million pounds (8,400 metric tons) of gizzard shad had been removed from the lake. This means about 129,000 pounds (58 metric tons) of phosphorus and 387,000 pounds (175 metric tons) of nitrogen were taken directly out of the lake through the fish. Also, by reducing the gizzard shad, the lake's phosphorus recycling was cut by about 322,000 pounds (146 metric tons). Nitrogen recycling was cut by about 1.9 million pounds (862 metric tons).
Restoring Aquatic Habitat
The District has planted wetland plants in Lake Apopka behind protective barriers. These plants provide homes for fish and other wildlife. As the lake's water quality gets better and clearer, these planting efforts are becoming less necessary. Native aquatic plants are starting to grow back on their own.
There is an ongoing effort to map where more than 350 beds of native underwater plants are located. This number changes each year.
Improved water clarity has also allowed an invasive plant called hydrilla to grow in the lake. Hydrilla can quickly take over and outcompete native plants. So, staff also work to find and treat these unwanted plants with special herbicides.
Challenges in Restoration
Restoring Florida's most polluted large lake has faced unexpected problems. For example, an estimated 676 birds died on former farmlands at Lake Apopka in late 1998 and early 1999. Most of these were American white pelicans, wood storks, and great blue herons. The main cause of these bird deaths was leftover organochlorine pesticide (OCPs) from farming. Birds got these chemicals by eating contaminated fish.
The District has done research to better understand how OCPs move through the food chain. This includes how they go from contaminated soil to fish, and then from fish to birds that eat them. The information learned from this research helps guide the restoration of the former farmlands at Lake Apopka. It also helps with other projects that aim to restore ecosystems damaged by farming.
Water Quality Improvements
Lake Apopka has shown improvements in its water quality. This is thanks to the reduction of phosphorus flowing into the lake from the surrounding land. Measurements of total phosphorus, chlorophyll (a measure of algae), and Secchi transparency (how clear the water is) all showed improving trends between 1987 and 2010.
However, during this 23-year period, three events caused the water quality to get worse for a short time.
- The first was a storm in March 1993. But the water quality started improving again the next year.
- The second happened in 2001 and 2002 at the end of a very bad drought. The lake lost almost 80% of its water, and phosphorus levels went up. But the improving trend continued the following year.
- Between 2004 and 2006, phosphorus levels were below 100 ppb and got close to the target of 55 ppb. These long-term improvements continued even after hurricanes in 2004 and 2005.
- The most recent event was a severe drought in 2007 and 2008. The lake lost up to 52% of its water. Phosphorus levels increased sharply when the lake was low. However, phosphorus levels dropped again in 2009 and continued to improve in 2010.
The most recent data from September 2011 showed that total phosphorus levels were 80 ppb. This was a 62% decrease compared to earlier levels. Chlorophyll a (algae) was 52 ppb, a 36% decrease. Water transparency (Secchi depth) was 14.6 inches (37 cm), which was a 53% increase, meaning the water was much clearer.
Summary of Accomplishments
In 2002, the District's Governing Board approved a rule. This rule limits how much phosphorus can be released into Lake Apopka or its streams from new construction. The District has worked with local, state, and federal agencies to achieve many things:
- They bought over 19,000 acres (7,700 hectares) of farmland along the lake's north shore. This reduced phosphorus pollution from farms. It also allowed them to restore the former marshes back into wetlands. About 10,000 acres (4,000 hectares) have been restored to wetlands.
- They operate the marsh flow-way. By 2010, this flow-way had removed about 19 metric tons of total phosphorus and about 32,000 metric tons of total suspended solids from Lake Apopka's water.
- They have harvested gizzard shad fish. From 1993 through December 2010, they removed over 58 metric tons of phosphorus and 175 metric tons of nitrogen from the lake through fish tissue.
- They replanted six types of native wetland plants in the water along the lake's shoreline. This helps bring back homes for fish and wildlife.
- They worked with the Friends of Lake Apopka and the East Central Florida Regional Planning Council. Together, they made a plan to ensure that future building projects do not harm the lake.
