Minimum Flows for the St. Marks River Rise Rule Development Workshop December 20, 2018
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT Statutory Requirements s.373.042, F.S. What is an MFL? Limit at which further withdrawals will cause significant harm to the water resources or ecology of the area. Purpose: To protect water resources and associated ecology. Provides information to support water supply planning and water use permitting evaluations. 2
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT Priority Waterbodies 3
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT St. Marks River Rise Study Area 4
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT St. Marks River Rise 237 cfs 689 cfs Spring Flow 452 cfs 5
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT Enhanced Data Collection • More than 60 sites • Hydrology – Aquifer levels – River stage and flow – Spring flow • Water Quality – Salinity – Temperature Insert picture of person collecting data 6
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT Enhanced Data Collection • Elevation Data – River channel – Floodplain • Ecological Data – Vegetation Communities – Instream Habitat Elevation Data 7
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT Baseline Time Series • No measurable impacts from withdrawals • Baseline is period of record: – (October 1, 1956 – November 27, 2017) 2000 St. Marks Rise Spring Discharge 2,000 Baseline Spring Flow (cfs) 1750 River Rise spring Discharge (cfs) 1500 1,500 1250 Flow (cfs) 1000 750 1,000 500 250 0 500 1/1/1956 1/1/1961 1/1/1966 1/1/1971 1/1/1976 1/1/1981 1/1/1986 1/1/1991 1/1/1996 1/1/2001 1/1/2006 1/1/2011 1/1/2016 0 0% 25% 50% 75% 100% 8 Date Exceedance Frequency
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT Florida Administrative Code (F.A.C.) Requirements Chapter 62-40.473(1), F.A.C. 1. Natural seasonal fluctuations in water flows or levels, 1. Natural seasonal fluctuations in water flows or levels, 2. Non-consumptive uses, and 2. Non-consumptive uses, and 3. Environmental values associated with coastal, estuarine, 3. Environmental values associated with coastal, estuarine, riverine, spring, aquatic, and wetland ecology, including: riverine, spring, aquatic, and wetland ecology, including: (a) Recreation in and on the water } (b) Fish and wildlife habitats and the passage of fish (c) Estuarine resources “Water (d) Transfer of detrital material Resource (e) Maintenance of freshwater storage and supply Values” (f) Aesthetic and scenic attributes (WRVs) (g) Filtration and absorption of nutrients and other pollutants; (h) Sediment loads (i) Water quality (j) Navigation 9
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT Water Resource Value Metrics • Recreation – Safe Power Boat Passage (2 ft x 30 ft) – Safe Canoe/Kayak Passage (1.5 ft Depth) • Fish and Wildlife Habitats – Fish Passage (0.6 ft Depth) – Manatee Passage (3.8 ft x 3.8 ft) – Floodplain Wetland Inundation – Instream Woody Habitat Inundation • Estuarine Resources – Low Salinity Habitats (Volume, Surface Area, Shoreline Length) 10
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT Hydrology Models • Models used to quantify changes in spring flow and WRV metrics – River hydraulic model – spring flow effects on river stage and flow – Estuarine Model – spring flow effects on salinity • Significant harm threshold: 15% reduction in metric 11
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT Results Allowable Flow Spring Flow Range Limiting Metrics Reduction (cfs) Low (<400 cfs) Dead Woody Debris Habitat 67 Live Roots Habitat 42 Hardwood Hammock 33 Medium (400 - 600 cfs) Cypress Hardwood Swamp 34 Boat Passage 40 Manatee Passage 50 Ironwood Hammock 50 High (>600 cfs) Ash Swamp 101 12
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT Results 13
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT Minimum Flow • Most limiting metric protective of full range of flows • Hardwood Hammock inundation: 33 cfs reduction when spring flow is 447 cfs • Applied to long-term average daily spring flow (452 cfs) Long-term Daily Percent Average Minimum Allowable Flow Allowable Flow Spring Flow Reduction Reduction (cfs) (cfs) (%) 419 33 7.3% 14 14
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT Peer Review • Independent experts in Hydrology, Ecology, and Environmental Flows • Scope of Peer Review – Supporting Data and Information – Technical assumptions – Procedures and Analyses 15
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT Peer Review Comments “…The Panel supports and endorses the District’s approach to determining the minimum flow and final selection of the minimum flow for the St. Marks River Rise and Spring Run.” Key Revisions • Improved riverine model and provided additional documentation • Removed boat launching metric • Reduced boat passage depth 16
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT Evaluation of Need for Prevention or Recovery Strategy • St. Marks River Rise currently meets the proposed minimum flow – No recovery strategy needed • Effects of projected withdrawals through 2040 do not exceed available spring flow of 33 cfs – No prevention strategy needed 17
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT MFL Assessment • MFL status anticipated to be assessed every 5 years • Difference between 30-year average flow and the baseline flow compared to the available water of 33 cfs • MFL anticipated to be reevaluated in 10 years 18
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT Rulemaking Schedule November 1, 2018 Notice of Rule Development was published December 20, 2018 Rule Development public workshop followed by 14 day public comment period February 28, 2019 Anticipated Board review and approval of draft rule language April 1, 2019 Deadline to publish Notice of Proposed Rule End of May, Anticipated effective date of Proposed Rule beginning of June, 2019 19
NORTHWEST FLORIDA WATER MANAGEMENT DISTRICT Thank You Insert background photo 20
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