Critique of North Branch of Sunrise

River TMDLNate Topie and Taylor Hoffman

Background

East Central MN, tributary of Sunrise River and part of larger St. Croix River Basin

Most of river basin has high or very high aquifer sensitivity to pollution

Land useType Percentage

Agriculture 58.1

Forest 8.3

Open Water 5.3

Forested Wetland 17.7

Non-Forested Wetland 8.0

Barren 0.1

Background Ctd.

Listed as impaired water under 303d of Clean Water Act due to Fecal Coliform Impaired for swimming & other primary contact

recreation

Fecal Coliform: bacteria present in intestines of warm-blooded animals Indicator for contamination by feces Indicator for presence of waterborne pathogens,

viruses, protozoa

Water Quality Standards

Standard Part 1: Monthly geometric mean should not exceed 200

organisms/100 mL Must have 5 samples per month

Standard Part 2: No more than 10% of samples taken during a month

can exceed 2000 organisms/100 mL

Standards only apply between April and October

Focused on geometric mean because less subject to random variation

Sunrise Water Quality Data

Data was collected from August-September in 1997, May-July in 1998, April-October in 2002-2003 Didn’t include 1997 data or previous data Little data for 2002-2003 seasons

Sampled at sites SUN-15 and SUN-5

Continuous flow data taken at SUN-5 and flow at other sites assumed to be proportional

Data for 2002-2003 were grouped together if from the same month

Sunrise Water Quality Data

Sunrise Water Quality Data

Sunrise Water Quality Data

Used month of June to calculate desired reduction because the month had the highest number of geometric mean exceedances 52% reduction=((geometric

mean-standard)/geometric mean) Seen as protective guideline But three out of five sample sites had less than 5

samples, what was required by standard

Not mentioned how many ‘wet’ or how many ‘dry’ samples were taken

2002 had a wet summer; 2003 had a wet spring Two seasons of data aren’t very representative of

system; no dry or very wet years present

Source Assessment

Source Assessment

TMDL and Allocations

Followed process developed by “Revised Regional TMDL Evaluation of Fecal Coliform Bacterial Impairments in Lower Mississippi River Basin in Minnesota”

WLA North Branch Wastewater Treatment Plant MS4

Determined from TMDL-WLAWWTP-MOS, which was divided between non-point and MS4 based on land percentages

Leaking septic systems; illegal straight pipes assumed to be zero

LA Non-point: livestock, septic systems, wildlife, pets outside of

MS4 Remaining 68% after WLAWWTP, MOS, and WLAMS4 were subtracted

from TMDL

Margin of Safety and Reserve Capacity

MOS given by difference between the central and lowest value for each zone Used this method because the allocations are direct

functions of daily flows MOS will account for flow variability

Reserve Capacity assumed equal to zero As growth increases, assumed that fecal coliform

will decrease Sewer systems with disinfection will take the place of

livestock populations

TMDL and Sources

Public Participation

Included organizations/persons such as: Minnesota DNR, MPCA, Chisago SWCD, North

Branch City Council, Wild River State Park, U of M Extension, volunteer stream monitors, landowners, and interested citizens.

Included a steering committee, public information meetings, and publications in local press

Monitoring Plan

Test specifically for E. coli instead of broadly fecal coliform

Monitor at same sites

Samples taken 5 times per month April through October

At least two seasons

Implementation

Focus on reducing top 3 sources (top 80%): unregulated livestock facilities, pasture near streams, and dangerous septic systems

Numerous financial incentives for landowners

Time frame: 5-10 years

Goals of Implementation

Reduce fecal coliform load from unregulated livestock facilities. Store waste, vegetative buffer strips, move fences,

clean lot

Reduce load from pastures near streams Move livestock, rotational grazing

Reduce load from septic systems Bring into compliance, switch to city sewer

Surface applied manure, pets, wildlife

Summary

Calculation of the components of the TMDL were valid (WLA, LA, MOS, Reserve Capacity)

52% reduction seems reasonable

Top three goals in implementation make sense Valid to focus on those sources for implementation

since they were derived from more reliable calculations

Would be easier to pinpoint and decrease (vs. wildlife fecal contamination)

The sources of those goals produced high amounts of fecal coliform during wet and dry periods

Summary

Could use more data Not enough grab samples in between two seasons

Below requirement of 5 samples per month Would make the geometric mean and therefore reduction goal

more accurate if more samples were taken Only two years used for data collection

Though they compared to 1998, could be helpful to include more years of data

Also, mentioned in beginning of report that there was close to 20 years of data; where is it/can it be used?

TMDL calculation was roughly approximated for some sources; however this couldn’t really have been improved