Board approves $2.19 million project to reduce phosphorus entering Lake Apopka

Four-quadrant design limits phosphorus movement

PALATKA, Fla., Dec. 8, 2020 — The St. Johns River Water Management District Governing Board today approved the contract for a $2.19 million project to reduce phosphorus loads to Lake Apopka through infrastructure improvements to the Duda portion of the North Shore.

“The Duda Property project exemplifies the type of restoration activity that reduces watershed inputs of phosphorous to the lake,” said St. Johns River Water Management District Executive Director Dr. Ann Shortelle. “This is one of many restoration projects at Lake Apopka funded through legislative dollars to improve water management on Lake Apopka North Shore wetlands and reduce phosphorus loading to the lake.”

The project will enhance the lake’s improving water quality as well as the District’s ability to increase water storage and improve the recovering wetlands’ habitat value.

Map of Lake Apopka Duda Water Storage Improvements

Lake Apopka Duda Water Storage Improvements

Overly enriched with nutrients, such as phosphorus and nitrogen, Lake Apopka has experienced persistent algal blooms for decades. The District’s restoration program works to reduce excessive nutrients in the lake by limiting the amount of nutrients and phosphorus entering the lake and removing accumulated phosphorous and sediments from the lake.

Since the late 1980s, the District’s work at Lake Apopka has resulted in phosphorus reductions of 64% while water clarity has increased by 55%. The recovery of clearer water and return of sunlight to the lake’s bottom has caused the regrowth of submerged aquatic vegetation, missing for 50 years, and improved critical largemouth bass habitat.

The District’s multipronged approach to Lake Apopka water quality restoration has been “diet and exercise.” “Diet” has focused on reducing the amount of phosphorus entering the lake. The largest “diet” improvement occurred following the Legislature’s 1996 direction to the District to buy out the farms on the North Shore.

“Exercise” is removal of phosphorus already in the lake, which has included harvest of gizzard shad from the lake since 1993 and operating the marsh flow-way since 2003 to continuously filter algae, suspended solids and associated nutrients.

As part of the District’s “diet” regimen, the Lake Apopka Duda Property Water Storage Improvement project involves raising internal levee heights and constructing hydraulic improvements to separate the property into four cells that can be independently managed. This work will allow an extra half a foot of water to be stored on the property, which will reduce pumped discharges and nutrient loads to Lake Apopka. The estimated total phosphorus load reduction to Lake Apopka is 390 pounds per year.

Other current projects at Lake Apopka include a pay-for-performance project that uses an innovative technology to remove phosphorus from the lake’s water; improvements to the marsh flow-way; infrastructure improvements that will allow more water storage, increase water management flexibility and reduce nutrient inputs to Lake Apopka; and projects to accelerate wetland restoration and recovery of aquatic plants.

The contract today was awarded to Westwind Contracting Inc., which expects to complete the project in summer 2021.

Lake Apopka, located about 15 miles northwest of Orlando, is the headwaters of the Ocklawaha Chain of Lakes and is the fifth largest lake in Florida. The Duda Property is located on the northeast shore of Lake Apopka.