62-304.640. Withlacoochee Basin TMDLs  


Effective on Thursday, January 30, 2020
  • 1(1) Rainbow Springs Group and Rainbow Springs Group Run. The nitrate TMDL is an in-stream monthly mean concentration of 0.35 mg/L and is allocated as follows:

    27(a) The Wasteload Allocation (WLA) for wastewater sources is not applicable.

    38(b) The WLA for discharges subject to the Department’s National Pollutant Discharge Elimination System Municipal Stormwater Permitting Program is to address anthropogenic sources in the basin such that in-stream nitrate concentrations meet the TMDL target, which, based on the mean concentrations from the 2000-2010 period, will require a 82 percent reduction of nitrate.

    91(c) The Load Allocations for nonpoint sources are to address anthropogenic sources in the basin such that in-stream nitrate concentrations meet the TMDL target, which, based on the mean concentrations from the 2000-2011 period, will require a 82 percent reduction of nitrate.

    133(d) The Margin of Safety is implicit.

    140(2) Lake Juliana. The nutrient TMDL for Lake Juliana is an annual geometric mean of 1.03 mg/L Total Nitrogen (TN), which is intended to achieve the applicable annual geometric mean chlorophyll 171a 172criterion for low color, high alkalinity lakes, and is allocated as follows:

    184(a) The WLA for wastewater point sources is not applicable;

    194(b) The WLA for discharges subject to the Department’s NPDES Municipal Separate Storm Sewer System (MS4) Permitting Program is a 40% reduction of TN based on mean concentrations from the 2003-2013 period.

    226(c) The Load Allocation (LA) for nonpoint sources is a 40% reduction of TN based on mean concentrations from the 2003-2013 period; and,

    249(d) The Margin of Safety is implicit.

    256(e) While the LA and WLA for TN have been expressed as the percent reduction needed to attain the applicable Class III nutrient criteria, it is the combined reductions from both anthropogenic point and nonpoint sources that will result in the restoration of nutrient conditions in the impaired waterbody. However, it is not the intent of this TMDL to abate natural background conditions.

    319(3) 320Gum Springs (Alligator Springs). 324The nutrient TMDL for Gum Springs (Alligator Springs) is an annual geometric mean (AGM) of 0.35 mg/L nitrate-nitrite at the spring vent, and is allocated as follows:

    351(a) The WLA for wastewater sources is not applicable;

    360(b) The WLA for discharges subject to the Department’s NPDES MS4 Permitting Program is a 78% reduction of nitrate-nitrite (calculated from 3811.58 mg/L), which is based on the highest AGM concentration from the 3932009 – 2017 period;

    397(c) The LA for n402onpoint sources is 78406% reduction of nitrate-nitrite (calculated from 1.58 mg/L), which is based on the highest AGM from the 2009 ‒ 2017 period, 427and

    428(d) The Margin of Safety is implicit.

    435(e) 436While the LA for nitrate-nitrite has been expressed as the percent 447reduction needed to attain the applicable Class III nutrient criteria, it is the combined reductions from both anthropogenic point and nonpoint sources that will result in the restoration of nutrient conditions in the impaired waterbody. However, it is not the intent of this TMDL to abate natural background conditions.

    496(4) 497Wilson Head Spring. 500The nutrient TMDL for Wilson Head Spring is an AGM of 0.35 mg/L nitrate-nitrite at the spring vent, and is allocated as follows:

    523(a) The WLA for wastewater sources is not applicable;

    532(b) The WLA for discharges subject to the Department’s NPDES MS4 Permitting Program is a 43% reduction of nitrate-nitrite (calculated from 5530.61 mg/L), which is based on the highest AGM concentration from the 5652009 – 2017 period;

    569(c) The LA for nonpoint sources is 43577% reduction of nitrate-nitrite (calculated from 0.61 mg/L), which is based on the highest AGM from the 2009 595‒ 2017 period, 598and

    599(d) The Margin of Safety is implicit.

    606(e) 607While the LA for nitrate-nitrite has been expressed as the percent reduction needed to attain the applicable Class III nutrient criteria, it is the combined reductions from both anthropogenic poi637nt and nonpoint sources that will result in the restoration of nutrient conditions in the impaired waterbody. However, it is not the intent of this TMDL to abate natural background conditions.

    668(5) 669Blue Spring (Citrus County). 673The nutrient TMDL for Blue Spring (Citrus County) is an AGM of 0.35 mg/L nitrate-nitrite at the spring vent, and is allocated as follows:

    697(a) The WLA for wastewater sources is not applicable;

    706(b) The WLA for discharges subject to the Department’s NPDES MS4 Permitting Program is a 61% reduction of nitrate-nitrite (calculated from 7270.90 mg/L), which is based on the highest AGM concentration from the 7392009 – 2017 period;

    743(c) The LA for nonpoint sources is 61751% reduction of nitrate-nitrite (calculated from 0.90 mg/L), which is based on the highest AGM from the 2009 769‒ 2017 period, 772and

    773(d) The Margin of Safety is implicit.

    780(e) 781While the LA for nitrate-nitrite has been expressed as the percent reduction needed to attain the applicable Class III nutrient criteria, it is the combined reductions from both anthropogenic poi811nt and nonpoint sources that will result in the restoration of nutrient conditions in the impaired waterbody. However, it is not the intent of this TMDL to abate natural background conditions.

    842(6) Lake Agnes. The nutrient TMDL for Lake Agnes is a seven-year average of annual loads of 10,896 lbs/year TN and 618 lbs/year TP, which are intended to achieve the applicable chlorophyll 875a 876criterion for low color and low alkalinity lakes, and is allocated as follows:

    889(a) The WLA for wastewater point sources is not a899pplicable;

    900(b) The WLA for discharges subject to the Department’s NPDES MS4 Permitting Program is a 41% reduction of TN (calculated from 18,552 lbs/year) and a 69% reduction of TP (calculated from 1,979 lbs/year) from the 2000-2016 period;

    939(c) The LA for nonpoint sources is a 41% reduction of TN (calculated from 18,552 lbs/year) and a 69% reduction of TP (calculated from 1,979 lbs/year) based on average loads from the 2000-2016 period; and,

    976(d) The Margin of Safety is implicit.

    983(e) While the LA and WLA for TN and TP have been expressed as the percent reduction needed to attain the applicable Class III nutrient criteria, it is the combined reductions from both point and nonpoint sources that will result in the restoration of nutrient conditions in the impaired waterbody.

    1033Rulemaking Authority 1035403.061, 1036403.067 FS. 1038Law Implemented 1040403.061, 1041403.062, 1042403.067 FS. 1044History–New 5-7-13, Amended 12-11-16, 10-29-19, 1-30-20.