Redwood River TMDL Critique

1. Redwood River TMDL Critique David De Paz, Alana Bartolai, Lydia Karlheim

2. IntroductionRedwood River • The Redwood River is impaired for both aquatic life and aquatic recreation due to fecal coliform and turbidity. • Our critique is on the TMDL for bacteria. • 8 reaches of the Redwood River fail to meet the water quality standard for bacteria (E. coli). [MPCA]

3. Watershed CharacteristicsRedwood River The impaired reaches are classified as: Recreation of all kind/aquatic life stringent 2B Aquatic life support and recreation 2C 2B General industrial purposes 3B 2C 7 Less stringent Limited resource value Note: Class 7 streams had not been assessed in this draft report but will be in 2010. Area: 705 sq. mile Tributary to the Minnesota River

4. Land UseRedwood River • Land Use • 85.5% Agriculture • 2.5% urban/Residential • Artificial drainage

5. BacteriaRedwood River Causes in the watershed: • failing septic systems -there are 1,948 subsurface sewage treatment systems. 1,051 are deemed “failing”, 334 are deemed “threats to public health” • wastewater treatment plant bypasses and flushes (there are 8 WWTP) • unsewered communities • livestock waste from feedlots • land applied manure (98% of total) • Domestic pets and wildlife [wolfenotes.com]

6. Sampling SitesRedwood River ’99-’06 ‘99 ‘74-’06 ’99-’06 ’99-’06 ‘99 ‘99 ‘03-’06 ‘99 [USEPA, 2011] Sites sampled by the MPCA and the Redwood-Cottonwood Rivers Control Area (RCRCA)

7. Fecal Coliform Redwood River Time Period: 1997-2006 [MPCA] (geometric mean by reach)

8. TMDL DevelopmentRedwoodRiver TMDLs were calculated for each of the 8 reaches at each flow condition (helpful for BMP implementation). TMDL= ∑ (WLAs + ∑ LAs + MOS + RC) nonpoint sources future development point sources accounts for uncertainty

9. TMDL Allocation WLA & LARedwoodRiver • Waste load Allocations (WLAs)- • NPDES permits= 0 (Livestock facilities that have been issued NPDES permits are assigned a zero WLA) • WWTF: assumed to be discharging the maximum of 200 orgs/100 mLs => overestimated • MS4(storm sewer systems): => MS4 + LA • The rest is assumed to be LA • Load Allocation (LA)- non-point sources not subject to NPDES permit • (except land applied manure)

10. TMDL Allocation MOS & RC Redwood River • Reserve Capacity (RC)- • Total RC== 0 because the watershed shows trends of decreasing population and stagnant animal numbers. • Note: The MPCA will reopen the TMDLs covered in this report if adjustments are required • Margin of Safety (MOS)- • calculated per flow zone since allocations = (flow) • x conversion factors => load • Implicit MOS: used when dry and low flow zone calculations used a concentration-based limit. In these conditions, flow is primarily GW fed and very little E. coli is conveyed.

11. TMDL AllocationsWest line to Threemile Creek • Land use : • 82.3 %cultivated • 10.9 % urban • 4.2 % grass • 2.0 % forest • 0.5% water/wetlands • 1 WWTF with MS4 permitcovering 2.86 % of the entire watershed • No feedlots with NPDES permits • 5472 animal units without permits • 140 SSTS units with 56 are failing. [MPCA]

12. TMDL AllocationsWest line to Threemile Creek [MPCA]

13. TMDL Required ReductionWest line to Threemile Creek 69.65% 60.55% 60.32% 58.42% 0% Inadequate Inadequate data data [MPCA]

14. Load Duration CurveWest line to Threemile [MPCA]

15. Implementation and BMPsRedwoodRiver Goal: Achieve water quality standards for fecal coliform bacteria within 10 years by educating, training, and providing monetary incentives. [MPCA] Note: Specific implementation plan will be made after TMDL gets approved

16. Critiques & Assumptions:Fecal Coliform/ E.coli • Unknowns of Fecal Coliform: • Survival rates • Fecal coliform may be higher when stream bed is aggravated (i.e. scouring events, runoff) [Davis et al. ,2005] [http://www.shardcore.org]

17. Fecal Coliform vs. E.Coli • Standard is normalized based on comparison studies by MPCA showing that 63% of fecal coliform will be E.Coli. Critiques & Assumptions:Fecal Coliform • E. coli samples converted using 179 E. coli = 200 cfumeaning that 89.5% of fecal coliform will be E. Coli. • Substantiated using 35 sample pairs from the same Watersheds between 1985-2006 [MPCA]

18. Several reaches don’t have sufficient flow monitoring data • USGS gage stations were used to find missing flow data • Duration of monitoring data varies between stations ’99-’06 ‘99 ‘74-’06 Critiques & Assumptions:Flow ’99-’06 ’99-’06 ‘99 ‘99 ‘03-’06 ‘99 [USEPA, 2011]

19. Critiques & AssumptionsImplementation • Livestock manure has environmental and economic benefits: • Less prone to erosion • Reduces commercial fertilizer • Wetland restorations • affects farmers • Streambank stabilization • Can be expensive • Livestock exclusions • Requires fencing and more management

20. Strength Required ReductionWest line to ThreemileCreek- site with largest reduction 69.65% 60.55% 60.32% 58.42% 0% Inadequate Inadequate data data [MPCA]

21. Strengths • TMDL broken up by flow andreach • 4 of the 8 reaches analyzed were not yet on the 303d list, but were included for thoroughness • Entire portion of report focuses on understanding E. coli sources • Willingness to reevaluate plan if/when changes occur ( i.e. population growth) [MPCA]

22. Questions? [confusedcow.webs.com]