Agenda Item Name:
Title
Newnans Lake Initiative Update
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Presenter:
Shane Williams, EP
Description:
A staff presentation on the project history of the Newnans Lake Improvement Initiative and proposed future efforts.
Recommended Action:
Recommended Action
Hear staff presentation on the project history of the Newnans Lake Improvement Initiative and proposed future efforts.
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Prior Board Motions:
8/24/2016 Board approves contract with FDEP for Phase 1 of the Newnans Lake Initiative.
4/5/2018 Board approves contract with FDEP for Phase 2 of the Newnans Lake Initiative and approves inter-fund loan from Stormwater Assessment to fund project.
2/28/2019 Board approves contract with SJRWMD for a second treatment weir on Little Hatchet Creek.
5/26/2019 Board approves inter-fund loan from Stormwater Assessment for the SJRWMD contract.
9/17/19 Board requested a presentation regarding the Newnans Lake Initiative
Fiscal Consideration:
Fiscal Consideration
N/A
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Background:
Newnans Lake was listed as an impaired waterbody in 2002 by FDEP. The cause of the impairment was determined to be nitrogen and phosphorus. The Lake has been included in the Orange Creek Basin Management Action Plan (BMAP) since 2004. The 2019 amendment to the BMAP specified load reduction allocations for each local Government within the Lake’s watershed. These allocations are for external load that is delivered to the lake. In addition to external loads, nutrients that have accumulated in the muck and sediment on the lake bottom are recycled into the water column when the bottom sediment are disturbed. The internal recycling of nutrients is the single largest source of nutrients in the lake.
In 2016 Phase 1 of the Newnans Lake Improvement Initiative was begun with $456,000 of legislative funding. The phase was completed in December of 2017 and resulted in an assessment of phosphorus sources and dynamics in Little Hatchet Creek and Gum Root Swamp and development of potential projects to reduce phosphorus loads including permeable reactive weirs for phosphorus reduction located in Little Hatchet Creek.
In 2018, Phase 2 was begun using $250,000 of legislative funding. This phase included additional project identification for Hatchet Creek and the design and permitting of a reactive treatment weir in Little Hatchet Creek for phosphorus removal. An additional treatment weir was funded in 2019 with cooperative funding from SJRWMD. Both weirs are scheduled for construction in December 2019.
In the current fiscal year, using stormwater assessment funds, Alachua County will complete a feasibility and preliminary siting and size study for a treatment wetland to address the internal recycling of nutrients. The County is also asking for state funding for a treatment wetland to be allocated in the 2020 legislative session.