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Floyds Fork Bacteria TMDL. Andrea M. Fredenburg Kentucky Division of Water TMDL Section November 28, 2012. Goals. Present watershed information Present TMDL calculations Provide example for one stream segment Vote on options for path forward to public notice. KY’s Bacteria Criteria.
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Floyds Fork Bacteria TMDL Andrea M. Fredenburg Kentucky Division of Water TMDL Section November 28, 2012
Goals • Present watershed information • Present TMDL calculations • Provide example for one stream segment • Vote on options for path forward to public notice
Monitoring Data • 319 (h) funded—Currys Fork and Bullitt Co. • MSD • Historical KDOW data • EPA funded—USGS data collection
Bacteria Impaired Segments • 18 impaired stream segments • 18 E. coli PCR • 4 Fecal coliform PCR • 4 Fecal coliform SCR • 26 listed waterbody/pollutant combinations
Potential Sources • KPDES-permitted sources to WLA • Others to LA
Sewer Lines* *Information Not Available for Jefferson County
Sewer Lines* *Information Not Available for Jefferson County
TMDL Calculation Example • South Fork Currys Fork 0.0 to 6.1 • E. coli PCR impairment • SFCF-2 USGS sample site
TMDL Equation TMDL (allowable # per day) = Allowable Concentration (allowable # per 100 ml) x Flow (in cubic feet per second) x Conversion Factor (24,465,758.4 per day) Conversion factor is figured as 1 cubic foot = 28316.85 ml and 1 day = 86400 seconds 1 x 1 cubic foot x 28316.85 ml x 86400 seconds = 24,465,758.4 100 ml second 1 cubic foot 1 day 1 day
Convert Gage Flow to TMDL Site Flow Flow at sample site = Acres of land draining to sample site ÷ Acres of land draining to gage site x Flow at gage Flow at sample site = 4672 acres ÷ 51136 acres x 233 cfs Flow at sample site = 21.3 cfs
Site SFCF-2 TMDL TMDL = Allowable Concentration x Flow x Conversion Factor TMDL = 240 E. coli colonies per 100 ml x 21.3 cfs x 24,465,758.4 per day TMDL = 125,068,956,900 E. coli colonies per day TMDL = 1.25E+11 E. coli colonies/day
Segment TMDL Segment TMDL = Site TMDL x Acres at downstream end of segment ÷ Acres at site Segment TMDL = 1.25E+11 E. coli colonies/day x 5949 acres ÷ 4672 acres Segment TMDL = 1.59E+11 E. coli colonies/day
TMDL and Flow TMDL = Allowable Concentration x Flow x Conversion Factor TMDL ≈ Flow Sample Load = Sample Concentration x Flow (on sample day) x Conversion Factor
TMDL Allocations TMDL = ∑WLA + ∑LA + MOS Explicit MOS is 10% of TMDL South Fork Currys Fork 0.0-6.1 Segment TMDL = 1.59E+11 E. coli colonies/day MOS= 1.59E+11 E. coli colonies/day x 10% MOS= 1.59E+10 E. coli colonies/day
SWS-WLA SWS-WLA = Allowable Concentration of Bacteria (#/100 ml) x Facility Design Capacity (Design Flow in cfs) x Conversion Factor (24,465,758.4/day) South Fork Currys Fork 0.0 to 6.1
Remainder Remainder = TMDL – MOS – ∑SWS-WLA South Fork Currys Fork 0.0 to 6.1 Remainder = 1.59E+11 - 1.59E+10 - 1.68E+09 Remainder = 1.42E+11 E. coli (colonies/day)
MS4-WLA MS4-WLA = # Acres of Developed Land in MS4 ÷ # Acres in Subwatershed x Remainder For South Fork Currys Fork 0.0 to 6.1 754 acres of developed land in the MS4 5948.52 acres in the subwatershed Remainder = 1.42E+11 E. coli (colonies/day) South Fork Currys Fork 0.0 to 6.1 MS4-WLA = 754 ÷ 5948.52 x 1.42E+11 MS4-WLA = 1.80E+10 E. coli (colonies/day)
Future Growth WLA Future Growth-WLA = Future Growth WLA Percentage x Remainder South Fork Currys Fork 0.0 to 6.1 754 acres of developed land 5948.52 acres of land in the subwatershed. Percent Developed Area = 12.68 (754 ÷ 5948.52 = 12.68%) • Future Growth WLA Percentage = 2%, Remainder = 1.42E+11 Future Growth-WLA = 2% x 1.42E+11 E. coli (colonies/day) Future Growth-WLA = 2.83E+09 E. coli (colonies/day)
LA ∑LA = TMDL - MOS - ∑WLA South Fork Currys Fork 0.0 to 6.1 TMDL = 1.59E+11 MOS = 1.59E+10 • ∑ SWS-WLA = 1.68E+09 • MS4-WLA = 1.80E+10 • Future Growth-WLA = 2.83E + 09 • ∑WLA =2.25E+10 ∑LA= 1.59E+11 – 1.59E+10 – 2.25E+10 ∑LA= 1.21E+11
The TMDLs and Allocations • E. coli PCR • Fecal coliform PCR • Fecal coliform SCR
Vote • TAC review/comments prior to public notice • TAC review/comments concurrent with public notice
Contact Information Andrea M. Fredenburg TMDL Section Division of Water 200 Fair Oaks Lane Frankfort, KY 40601 Andrea.Fredenburg@ky.gov