Lake Tohopekaliga Nutrient Reduction Plan Two Years Later

Transcription

1 Lake Tohopekaliga Nutrient Reduction Plan Two Years Later Danielle Honour, P.E., D.WRE Kimberly Lawrence Florida Stormwater Association Annual Conference June 12, 2014

2 Nutrient Reduction Plan Timeline

3 Overview of Lake Toho Impairment November 2010: Placed on Verified List by FDEP Category 5: Impaired and Total Maximum Daily Load (TMDL) required Initially impaired for nutrients due to increasing trend of Trophic State Index (TSI) Osceola County and City of Kissimmee disagreed Independent analysis showed no TSI Impairment Ambient nutrient content not related to algae Upper Kissimmee Planning Unit Source: FDEP, 2011

4 Overview of Lake Toho Impairment (cont.) FDEP reconsidered impairment Agreed more research was needed Imbalance of flora and fauna due to excessive macrophytes (hydrilla) December 2011: Nutrient Reduction Plan (NRP) completed February 2012: Final Listing Category 4e : Impaired but ongoing restoration activities underway, no TMDL required

5 NRP Process Timing and Applicability Evaluation ***Prior to TMDL adoption*** Nutrient Reduction Plan Implementation Strategic Monitoring and Initial Assessment Causative pollutant is questionable or uncertain Highly managed or variable systems Final Impairment Listing & Adoption Marginal impairment fluctuates over time

6 The TMDL Process Input based on findings during plan implementation and monitoring Evaluation Objectives, concerns, local knowledge, management activities, monitoring plan, data collection Implementation (e.g., BMAP) Strategic Monitoring and Initial Assessment Development of Basin Management Action Plans (BMAPs) NRP/RAP Ability to Challenge Final Impairment Listing and Adoption Review data and calculations, questions/ comments, reasonable assurance plan Public meetings, input and comments on plan development and final allocations Development and Adoption of Total Maximum Daily Loads (TMDLs) Public workshops, input and review on appropriateness of targets set, initial allocations and modeling

7 What is a Nutrient Reduction Plan? Hybrid of a Basin Management Action Plan (BMAP) and Reasonable Assurance Plan (RAP) Key Differences: No water quality targets are set No allocation of load reductions Not a long term solution: stepping stone Monitoring plan and research priorities will align to the goals and objectives identified by the stakeholders to determine future targets Plan is not formally adopted

8 Lake Tohopekaliga (Toho) Background Upper Kissimmee River Basin Headwaters to the Everglades Watershed area = 473 sq. mi. Lake = 34 sq. mi. Class 3 fresh water lake Popular for fishing, hunting, boating, bird watching and sightseeing Economic importance

9 What Makes Lake Toho Special Highly managed since the 1960s Water level stabilization (1960s) Sewage treatment plant effluent discharges (1940s to 1980s) Major drawdowns to improve habitat (1969, 1979, 1987, 2004) Introduction of Hydrilla species into the lake (1980s) Change in Hydrilla management to support endangered snail kites Impact of management activities still not fully understood

10 Nutrient Reduction Plan Elements Pollutant Load Analysis Runoff based TN and TP Loads by Jurisdiction Management Actions BMPs to reduce TN and TP loads Research Priorities Hydrilla Literature Review Strategic Monitoring Plan Establish monitoring network Track Implementation Plan Commitment

11 Tracking Implementation 2014 Biennial Update Report Coordination with FDEP on update elements Accomplishments by participants Research and monitoring Monitoring results and trends Research accomplishments Implementation issues Future activities Feedback from FDEP Detail on projects Public education activities

12 Lake Tohopekaliga Monitoring Builds on existing efforts by municipal stakeholders and SFWMD Data evaluated by WBIDs Consistent with FDEP approach under Impaired Waters Rule Mann Kendall test to determine statistical significance Analyzed statistical long term (where available) trends Tributary monitoring Continued in lake monitoring

13 Tributary Water Quality Trend Analysis Statistically Significant Results ( ) 95 percent confidence level (P < or = 0.05) Remaining Tributary WBIDs no trend WBID TKN NO2 /NO3 TP Chl a Avg. Concentration Slope of Trend ( /yr) Hart Branch N/A 1.19 mg/l Boggy Creek N/A 0.02,0.00 mg/l 0.001, E. Lake Toho Drain N/A E. Lake Toho 4 ug/l Shingle Creek N/A 0.83 mg/l St. Cloud Canal N/A 0.76 mg/l Mill Slough N/A 0.65 mg/l Improving Declining - - No Trend

14 Lake Toho Water Quality Trend Analysis Results ( ) Parameter Statistically Significant Trend Slope of Trend ( /yr) Total Phosphorus as P Decreasing Orthophosphate as P (mg/l) Decreasing Total Kjeldahl Nitrogen as N (mg/l) Increasing Nitrate/Nitrite (mg/l) None Chlorophyll a None Turbidity (NTU) Increasing Color (PCU) Decreasing ph (SU) Increasing Conductivity (µmhos/cm) Increasing Excluded 2003/2004 drawdown years due to possible anomalies

15 Completed Literature Review on the Relationship Between Hydrilla and Nutrients Information on the impact of large scale aquatic plant management on water quality is not readily available Hydrilla has the ability to retrieve nutrients from both roots and shoots to varying degrees Derives primary nutrition from bottom sediments Water column nutrients have minimal influence on the ability to colonize large areas of the KCOL Estimated sediment reserves of N&P and internal cycling of nutrients are adequate to sustain populations for extended periods of time Water Column Nutrients and Abundant Hydrilla Growth on Lake Tohopekaliga (Netherland et. al, 2012)

16 Completed Literature Review on the Relationship Between Hydrilla and Nutrients Hydrilla Growth on Lake Toho will continue Shallow nature of lake Large sediment pools of N&P Water schedules that promote stabilization Physiological adaptations Invasive traits of the plant Even if inflowing N&P are reduced Water Column Nutrients and Abundant Hydrilla Growth on Lake Tohopekaliga (Netherland et. al, 2012)

17 Here Comes the Lake Okeechobee BMAP BMAP process initiated in 2013 Drainage area spans over 3.5 million acres Lake O TMDL Target Concentration 0.04 mg/l TP Target Load 140 MT/year (~63% reduction) Northern Six Sub Watersheds is the focus of the BMAP Upper Kissimmee Lower Kissimmee Lake O Watershed Land Use % Lake Istokpoga Indian Prairie Agriculture 51.2 Fisheating Creek Taylor Creek/Nubbin Slough Natural Areas Urban

18 Lake O BMAP TP Loading Summary Sub Watershed Area (ha) Attenuated TP Load (MT/yr) %Load TP Reductions (MT/yr) Fisheating Creek 128, % 6.01 Indian Prairie 111, % 6.22 Lake Istokpoga 159, % 132 Lower Kissimmee 173, % Taylor Creek/Nubbin Slough 80, % Upper Kissimmee* 416, % 4.32 *Lake Toho located in Upper Kissimmee Sub watershed Total 1,070, % 59.0 What is the non attenuated source reduction needed to meet the attenuated reduction requirements? Cost per lb. reduced in Lake O become $$$

19 Upper Kissimmee s Sub Watershed Upper Kissimmee s Sub Watershed Lowest average TP concentration Highest Discharge Stakeholder ability to manage flow? Water Years Source: FDEP, 2013

20 Lake Toho s Role in the BMAP Lake Toho Watershed Located in Upper Kissimmee Sub Watershed 11% of the area in Lake O Northern Tributary Sub Watersheds Contains the majority of the urban area (MS4) Lake Toho Average TP: 0.05 mg/l Source: SFWMD, 2011

21 Stakeholders Have High Hopes for NRP s Role in Lake O BMAP Gives NRP stakeholders a head start Strategic monitoring already in place Demonstrated TP has been consistently decreasing in Lake Toho Stakeholders already have projects and implementation underway Streamlines process of submitting projects Loads reductions will be re calculated due to different tools

22 As a Result, Water Quality Mandates are Driving the County s Master Planning Process County Comprehensive Plan requires stormwater master plan update every 5 years Previous updates historically flood control driven Designed a Master Plan to support existing and anticipated water quality requirements Completed County Wide Master Plan Update in early 2014

23 Master Plan Designed to Support Existing and Anticipated Water Quality Requirements Water Quality Regulatory Framework (TMDL, BMAP, NRP, NNC, Impaired Waters, ERP, NPDES, LOPP) Water Quality Trend Analysis Non TMDL waterbodies Included pristine waters to determine trends County wide pollutant load analysis Consistent with NRP approach Delineated BMP tributary area coverage

24 Master Plan Designed to Support Existing and Anticipated Water Quality Requirements (cont.) Basin Prioritization Emphasis on impaired waters, NRP and Lake O BMAP subbasins Urban Loads Flooding Recreational Value Future Growth Previously Completed Study

25 Master Plan Designed to Support Existing and Anticipated Water Quality Requirements (cont.) Conceptual alternatives analysis Focused on top ranked subbasins Focused on storage for water quality/quantity Provides options for County to consider Load reduction estimates Cost/lb nutrient removal Ranking and prioritization E. Lake Toho

26 Upcoming Activities and Lessons Learned Lake Toho will be assessed with NNC in future assessments NRP does not suit every scenario Process helped stakeholders identify what we know & what we don t know Demonstrated who controls what Still too early to determine if further reductions will be needed from Lake Toho stakeholders Does meeting the Lake O target mean Lake Toho will no longer be impaired?

27 Questions??? Danielle M. Honour, P.E., D.WRE Kimberly Lawrence