St. Johns River Water Management District And Andrew rew Suthe utherland land, , PhD hD MF MFLs Technical Program m Ma Manager Division of Wa Water Supply Planning and Assessme ment
Statut utor ory Dir irect ectiv ive Water management districts must establish MFLs that set… “…the limit at which further withdrawals would be significantly harmful to the water resources or the ecology of the area.” Section 373.042(1), Florida Statutes (F.S.)
Statut utor ory Dir irect ectiv ive “…consideration shall be given to… non-consumptive uses, and environmental values …” 62-40.473, F.A.C. • Recreation in and on the water • Fish & wildlife habitats and the passage of fish • Estuarine resources • Transfer of detrital material • Maintenance of freshwater storage & supply • Aesthetic and scenic attributes • Filtration / absorption of nutrients & pollutants • Sediment loads • Water quality • Navigation
SJRWMD MFLs MFLs Determination • Determine the most critical environmental features to protect and the minimum hydrologic regime required for their protection (MFLs condition) MFLs Status Assessment • Determine the baseline hydrologic regime that represents current conditions (Baseline condition) • MFL and Baseline conditions are compared to determine water available
amount available for withdrawal (sustainable yield) Baseline condition Lake Level / River Flow amount needed to sustain surface water environment and MFL condition beneficial uses Time
MFLs Determination Protect Natural Flow/Stage Variability Communities and Species adapted to High and Low Events IH: upland encroachment FH: wetland inundation Lake MA: organic soils FL: wetland regeneration IL: fish passage
MFLs Determination MFLs are Events Magnitude, Duration and Frequency flooding events of varying duration and frequency target Water Level elevation drying events of varying duration and frequency Time
MFLs Determination Critical Event: Frequent Flood Event frequent flood needed to maintain extent of Magnitude: HS mean elev. hardwood swamp Duration: ≥ 30 days Return Interval: 2 years mean elevation of swamp Upland HH Hardwood Swamp TZ Marsh
MFLs FLs Status us Asses essment ment Current Status of MFLs Use long-term hydrologic model simulations • Groundwater model used to determine effect of current • pumping Compare the frequency of a critical events • Baseline Condition vs MFLs Condition • Determine water availability (freeboard) or deficit • Future Status of MFLs • Use 20-yr projected ground water use Groundwater model used to determine effect of projected • pumping and remaining freeboard 9
Prevent ention & ion & R Reco ecover ery Strategies gies Surface water and Groundwater Models Key for Assessment No action Are MFLs met under Yes required 2035 water demand? No Prevention Yes strategy Are MFLs met under current water Recovery demands? No strategy 10
Upper Upper Oc Ocklaw klawaha aha Riv iver er Bas asin in (UOR UORB) Lak Lakes es MFLs FLs
2019 Wekiva River at SR 46 Rock Lake Griffin Springs Wekiwa Springs Harris Chain of Lakes (Beauclair, Dora, Eustis, and Harris) Little Wekiva River and associated springs Lake Apopka DRAFT
UOR UORB Lak Lakes es M MFLs FLs Environme mental Analyses • Fieldwork complete • WRVs analyses - ongoing Mo Modeling • Calibrated model: • Peer reviewed • Updates near completion • MFLs assessment - ongoing DRAFT
Ne Next xt S Steps eps Est. Dates • Post model peer review responses to website… June 2018 • External peer review of UORB MFLs report …... March 2019 • Notice of Rule Development …………………...... October 2019 • Rulemaking workshop ……………………………. November 2019 • Notice of Proposed Rule …………………………. December 2019 DRAFT
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