redwood river tmdl critique

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

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Redwood River TMDL Critique. David De Paz, Alana Bartolai , Lydia Karlheim. Introduction Redwood 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. - PowerPoint PPT Presentation

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Page 1: Redwood River TMDL Critique

Redwood River TMDL Critique

David De Paz, Alana Bartolai, Lydia Karlheim

Page 2: Redwood River TMDL Critique

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]

Page 3: Redwood River TMDL Critique

Watershed CharacteristicsRedwood River

Area: 705 sq. mileTributary to the Minnesota River

The impaired reaches are classified as:

2B

2C

3B7

2B

2C

Recreation of all kind/aquatic life

Aquatic life support and recreation

stringent

Less stringent

General industrial purposes

Limited resource value

Note: Class 7 streams had not been assessed in this draftreport but will be in 2010.

Page 4: Redwood River TMDL Critique

Land UseRedwood River

• Land Use– 85.5% Agriculture– 2.5% urban/Residential

• Artificial drainage

Page 5: Redwood River TMDL Critique

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

Standard only valid

April -October

Class 2B/2C(organisms/

100mLs)

Class 7(organisms/

100mLs)

E. coli 126 630

Fecal coliform 200 1000

[wolfenotes.com]

Page 6: Redwood River TMDL Critique

Sampling SitesRedwood River

[USEPA, 2011]

‘99

‘03-’06

‘99

‘99

’99-’06‘99

’99-’06

’99-’06

‘74-’06

Sites sampled by the MPCA and the Redwood-Cottonwood Rivers Control Area (RCRCA)

Page 7: Redwood River TMDL Critique

Fecal Coliform Redwood River

[MPCA]

Time Period: 1997-2006

(geometric mean by reach)

Page 8: Redwood River TMDL Critique

TMDLs were calculated for each of the 8 reaches at each flow condition (helpful for BMP implementation).

TMDL= ∑ (WLAs + ∑ LAs + MOS + RC)

TMDL DevelopmentRedwood River

point sources

nonpoint sources

accounts for uncertainty

future development

Page 9: Redwood River TMDL Critique

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)

TMDL Allocation WLA & LARedwood River

Likely non-point sources

Land-applied manure

inadequate human WW treatment

Non-permitted municipal stormwater systems

Pets/wildlife

Page 10: Redwood River TMDL Critique

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.

TMDL Allocation MOS & RC Redwood River

Page 11: Redwood River TMDL Critique

TMDL AllocationsWest line to Threemile Creek

[MPCA]

Land use :• 82.3 %cultivated• 10.9 % urban• 4.2 % grass• 2.0 % forest• 0.5% water/wetlands• 1 WWTF with MS4 permit covering

2.86 % of the entire watershed • No feedlots with NPDES permits • 5472 animal units without permits• 140 SSTS units with 56 are failing.

Page 12: Redwood River TMDL Critique

TMDL AllocationsWest line to Threemile Creek

[MPCA]

Page 13: Redwood River TMDL Critique

TMDL Required ReductionWest line to Threemile Creek

[MPCA]

58.42%

69.65%

60.32% 60.55%

0%Inadequate

dataInadequate

data

Page 14: Redwood River TMDL Critique

Load Duration CurveWest line to Threemile

[MPCA]

Page 15: Redwood River TMDL Critique

Implementation and BMPsRedwood River

[MPCA]

BMPs:CRP buffers

alternative tile intakes

grassed waterways

livestock exclusion

sediment basins

nutrient management plans

wetland restorations

streambank stabilization

Goal:Achieve water quality standards for fecal coliform bacteria within 10 years by educating, training, and providing monetary incentives.

Note: Specific implementation plan will be made after TMDL gets approved

Page 16: Redwood River TMDL Critique

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]

Page 17: Redwood River TMDL Critique

Critiques & Assumptions:Fecal Coliform

Fecal Coliform vs. E.Coli• Standard is normalized based on comparison studies by MPCA showing that 63% of fecal

coliform will be E.Coli.

• E. coli samples converted using 179 E. coli = 200 cfu meaning that 89.5% of fecal coliform will be E. Coli.

• Substantiated using 35 sample pairs from the same Watersheds between 1985-2006

[MPCA]

Standard only valid

April -October

Class 2B/2C(organisms/

100mLs)

Class 7(organisms/

100mLs)

E. coli 126 630

Fecal coliform 200 1000

Page 18: Redwood River TMDL Critique

Critiques & Assumptions:Flow

• 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

[USEPA, 2011]

‘99

‘03-’06

‘99

‘99

’99-’06‘99

’99-’06

’99-’06

‘74-’06

Page 19: Redwood River TMDL Critique

Critiques & AssumptionsImplementation

BMPs:

CRP buffers

alternative tile intakes

Grassed waterways

livestock exclusion

sediment basins

nutrient management plans

wetland restorations

streambank stabilization

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

Page 20: Redwood River TMDL Critique

Strength Required ReductionWest line to Threemile Creek- site with largest reduction

[MPCA]

58.42%

69.65%

60.32% 60.55%

0%Inadequate

dataInadequate

data

Page 21: Redwood River TMDL Critique

Strengths• TMDL broken up by flow and reach

• 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]

Page 22: Redwood River TMDL Critique

Questions?

[confusedcow.webs.com]