SFWMD projects to reduce nutrient load entering lake

Posted 5/13/21

WEST PALM BEACH – “Lake Okeechobee really is the heart of the Everglades. What are we doing to take care of that beating heart of the Everglades?” asked Jennifer Reynolds, South …

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SFWMD projects to reduce nutrient load entering lake

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WEST PALM BEACH – “Lake Okeechobee really is the heart of the Everglades. What are we doing to take care of that beating heart of the Everglades?” asked Jennifer Reynolds, South Florida Water Management District (SFWMD) Ecosystem Restoration and Capital Projects Division Director at the May 13 meeting of the SFWMD governing board.

“Decades of nutrient pollution has flowed into Lake Okeechobee and runoff continues to be a problem,” she said.

“We have doubled our monitoring network,” she said. This data helps SFWMD evaluate how well projects are working,” she said. “We are delineating areas in our northern watershed. In those basins where we have monitoring, evaluating types of nutrients.

“None of us can do this alone. It’s a really big problem. It’s a problem that we share but we also share the solution. Florida Department of Environmental Protection (FDEP), FDACS and SFWMD need to work together,” Reynolds said.

The Lake Okeechobee watershed extends from Orlando to the northern shores of Lake Okeechobee covering about 3.5 million acres.

The TMDL is a goal of how much nutrient load can go into the lake and be sustainably incorporated into the ecosystem without causing harm, Reynolds said. That goal for Lake Okeechobee is 140 metric tons of phosphorus. That includes 35 metric tons of phosphorus that enters the lake via rainfall.

The phosphorus level in the runoff should be around 105 metric tons a year, Reynolds said. “We’re a lot higher than that – about four times higher than that.”

FDEP Basin Management Action Plan sets the goals and also ranks which basins contribute the most phosphorus to the flow entering the lake. Eighteen of the 64 basins were designated as priority 1, she said.

“We looked at the 18 priority basins and further selected watersheds based on nutrient loading from last five years of data,” Reynolds explained. The top priorities were Taylor Creek/Nubbin Slough and Indian Prairie.

The third priority is the Lower Kissimmee basin.

Reynolds said this focuses limited funding in areas where projects could have the greatest immediate impact.

“A lot of the nutrient loading has to do with the amount of rainfall and the amount of runoff,” Reynolds said. “The more rainfall, the more runoff and the more nutrient loading you are going to have.” She said it’s important to consider both runoff and the concentration within that runoff.

A project that can store where there is a lot of runoff can be effective. In a small area with high concentration, a nutrient removal project can be effective.

Indian Prairie Watershed

Projects in the Indian Prairie Watershed include:

• Lykes West Waterhole, a 2,370-acre public-private partnership diverts and treats water from the C-40 canal before it enters Lake Okeechobee. Longterm average benefit is reduction of 5.3 metric tons of phosphorus and 24 metric tons of nitrogen per year.

• Buck Island Ranch, 4,607-acre private-public partnership retains stormwater in ditches and improved pastures to reduce runoff entering the lake. An 188-acre component at Buck Island Ranch is a new concept. They are growing feed for cattle and harvesting it, removing that nutrient load from the basin. Total storage is about 2,193 acre feet per year. Total phosphorus reduction is about 0.71 metric tons per year.

• Istokpoga Marsh Watershed Improvement is a 308-acre stormwater impoundment owned by Highlands County. Estimated long-term average benefit is reduction of 1.36 metric tons of phosphorus.

• Brighton Valley is a public-private partnership that focuses on water storage. The 8,142-acre project diverts and treats water from the C-41A canal before entering Lake Okeechobee. Estimated long-term average benefit is 3.2 metric tons of phosphorus and 27.3 metric tons of nitrogen removed.

Taylor Creek Nubbin Slough

In Taylor Creek Nubbin Slough Basins:

• Taylor Creek STA is a 118-acre STA, that diverts and treats runoff from upper Taylor Creek before entering Lake Okeechobee. Estimated long term average reduction of phosphorus is 1.9 metric tons per year. Reynolds said in 2016, 700,000 acre feet of water inflowed into this STA. That year, they saw a phosphorus load reduction of about 56%. Years with less water going through the STA have lower total removal rates but the percent reduction stays above 50%.

• Lakeside Ranch STA is a 1,707-acre STA. Estimated average phosphorus reduction is 11.5 metric tons per year. “We’re seeing a 93% removal rate out of that STA. It’s really producing great benefits,” said Reynolds. A water control structure that has recently come online will keep water flowing to this STA year round.

• Nubbin Slough STA is a 770-acre STA. Some of the water control structures were leaking, causing it to lose water. This reduced the effectiveness of the STA. It is offline for repairs.

• Brady Ranch STA is a 1,800-acer Flow Equalization Basin (FEB) and Aquifer Storage and Recovery (ASR) project to expand regional storage and reduce nutrient loads. Estimated long-term average benefit is 7,200 acre feet of water storage and phosphorus reduction of 3.95 metric tons per year. This project is still in the design.

• Grassy Island FEB and ASR is on the 4,000-acre property owned by SFWMD. About 800 acres is available for construction of the project. It will expand regional storage and reduce nutrient loads as well as assist with the Taylor Creek STA. Estimated long-term average benefit is 3,200 acre feet of storage and phosphorus reduction of 0.79 tons of phosphorus per year.

• Dixie Ranch is a public-private partnership. This 3,771-acre public-private partnership is a storage project to capture rainfall and reduce runoff entering the lake. Estimated long-term benefit is 856 acre-feet of water per year.

“Are we trying to tackle 300 tons with our projects alone? No,” said Reynolds. Some of it will be tackled by regulations by FDEP, some will be solved on agricultural lands through the Best Management Practices (BMPs) regulated by FDACS. BMPs require farmers and ranchers to limit fertlizer use to that is shown to be needed by soil and leaf tests, use more efficient means of fertilizing plants and/or restrict runoff from their property.

FDACS sends FDEP a list of all agriculture operations who are not enrolled in the FDACS BMP program. If a property is getting the agriculture classification on the tax roll, the property owner is required to enroll in the BMP program or do water quality monitoring.

“We’re taking a look at the difference in the type of phosphorus, whether it is a suspended solid or dissolved in the water column,” she said. Testing can determine the difference between the legacy phosphorus and new phosphorus. Sediment-based phosphorus is the legacy phosphorus, she said. New phosphorus includes fertilizer in runoff.

“In the lake itself, we have a huge legacy problem,” she said.

“If there is no reasonable responsibility in what is coming into state waters, I don’t know how you can ever achieve the reduction of 300 metric tons of phosphorus,” said SFWMD Board Member Ron Bergeron.

Chris Pettit, director, Office of Agricultural Water Policy at Florida Department of Agriculture and Consumer Services, said FDACS does research with University of Florida and FDEP to make sure the BMPs work. For example, for the cattle ranching manual, “we had over 200 pieces of documentation to support that manual,” he said. “We are dealing with efficiency in input as it relates to our program.”

He said the statute provides FDEP with the ability to do representative site monitoring to look at the sub-watershed impacts.

Reynolds said it takes at least three years of water quality data to identify a trend.

At the May 13 meeting, Reynolds asked the SFWMD board to consider two new projects. One project would be in the lower Kissimmee basin that has water going into Lake Okeechobee. This area receives water from a large watershed.

She said they worked with FDEP because SFWMD cannot do such a large project with their limited funding. She said they are looking for a private partner to acquire the land, design a project and operate the project for a 5-year period. At the end of the 5-year period, the project and land would be turned over to SFWMD. The project would achieve a minimum reduction of 13 to 15 metric tons of phosphorus per year.

She said they received two proposals from EIP Florida Water Quality LLC and HGS LLC.

EIP owns two ranches of approximately 3,500 acres, straddling the L-62 canals and adjacent to the Kissimmee River. The project would hold water and flow it through STAs. They would also use inovative methods to reduce phosphorus load in the water. Reynolds said the cost of the project would not exceed $300 million and would be funded by $12.6 million in state dedicated funds with the remainder to come from future state funding.

“We haven’t negotiated the terms of the agreement,” she said.

In the public comment period, Mike Elfienbein said he proposed a project that would take more phosphorus out of Lake Okeechobee and the district “decided it wasn’t worthy of its time, money and effort.” Despite widespread support from the counties in the district, his $500,000 project that afforded a more-cost effective solution was “pooh-poohed” by SFWMD, he said.

“When the BMAP (basin management action plan) was adopted in 2014, the goal was to meet the TMDL by the year 2034,” said Paul Gray of Audubon Florida. He said the FDEP plan doesn’t come close to reaching the TMDL goals. “Storage is the first thing in cleaning water. After (Hurricane) Irma, 1.5 million acre feet of water went into Lake Okeechobee at one time,” he said. Storage is essential to cleaning the water before it goes into the lake, he said.

“We’ve long been advocates for northern storage,” said Nyla Pipes of One Florida Foundation. She said a project that is going to cost up to $300 million deserves more discussion before approval.

Benita Whalen of Florida Cattlemen’s Association said every watershed plan includes regional projects as well as BMPs. BMPs alone won’t provide the solution. The solicitiation period for this project was fairly short, she added. She said she knows other property owners are intersted in doing projects. The accumluation of legacy phosphorus is in the lake, in the canals and in the soils of the watershed, she added.

The governing board voted unanimously to move forward with negotiations on the project.

Sean Sculley, chief of the SFWMD Applied Science Division, asked the governing board to approve an innovative technology project to remove phosphorus from the water.

The project was chosen by district staff to be located in the S-191 basin. In the past five years, the basin has expored an average of 63 metric tons of phosphorus. It will compliment projects in the Taylor Creek/Nubbin Slough basins. It will be funded with $3 million grant from FDEP and $3 million from the Northern Everglades and Estuaries Protection Plan funds for total cost of up to $6 million.

Ferrate Solutions Inc. submitted a bid of $154 per pound of phosphorus removed.

“The risk is bourne on the contractor,” he said.

The water will be removed from the C-59 canal and treated with a ferrate additive, an iron complex containing oxygen. The ferrate binds with the phosphorus by way of a quick oxidation and coagulation process and is then removed by sedimentation.

The contractor is expected to remove 18 metric tons of phosphorus during this contract.

The SFWMD unanimously voted to move forward with the contract.

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