Zumbro River Watershed TMDLs

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Zumbro River Watershed TMDLs With some focus on
Lake Shady Lake Shady Cafe August 3,
2009 Minnesota Pollution Control Agency Barr
Engineering, Inc.
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Presentation Outline

• TMDL Overview Preliminary Results (10-15
  minutes)
• TMDL work as it relates to Lake Shady
• Watershed management (2 minutes)
• Cursory look at sites up and down of Lake Shady
  (10-15 min)
• IF TIME Historical pollutant loading at SF
  Zumbro site (5 minutes)
• Discussion/Questions (open ended)

Zumbro River North Rochester at 75th Street
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Lake Shady
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YOU ARE HERE
SF 232,574 acres MF 277,832 NF 153,149 LK
34,881 LOW 211,903
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Basin Update Impaired Waters Process at Forefront
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Background Impaired Waters

• In the 1970s, the Clean Water Act provided
  motivation and funding to identify water quality
  problems and to develop solutions to correct
  these problems
• States have a responsibility to create water
  quality standards that are based on the
  designated uses of water bodies.
• States are also required to assess water bodies
  (such as a lakes, rivers, and streams) and use
  the information to identify waters not meeting
  water quality standards (303d list)

Note fact sheets
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Impairment Examples

• Affected Use gtgt Assessment Parameter
• Aquatic Consumption gtgt mercury
• Aquatic Recreation gtgt pathogens (E. coli)
• Aquatic Recreation gtgt excess nutrients
  (phosphorus)
• Aquatic Life gtgt Turbidity

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Turbidity Visuals
0-3 NTU
0-3 NTU
12-20 NTU
12-30 NTU??
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Turbidity Background Cont

• Minnesotas turbidity water quality standard 25
  NTU (10 NTU coldwater)
• Waters with turbidity over 25 NTU can stress
  aquatic life
• Waters that go over 25 NTU repeatedly are
  considered impaired

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Why is Turbidity an Issue?

• Impacts to Recreation
• Reduced visibility for swimmers and boaters
• Reduced sportfish populations
• Impacts to Health
• Increased potential for waterborne diseases from
  recreation
• Increased need for drinking water treatment
• Impacts to Aquatic Life
• Reduced light for submerged aquatic plants
• Increased temperatures
• Reduced oxygen levels

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Background Excess Nutrients DemandSupply
Affected Use Aquatic Recreation
Note fact sheets
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Background TMDLs

• Total Maximum Daily Loads (TMDLs) are required to
  be developed for each pollutant in a water body
  on the 303d list (also known as the impaired
  waters list)
• In general terms, a TMDL is the amount of a
  specific pollutant that a water body can receive
  and attain and maintain a given water quality
  standard
• Point and nonpoint sources of pollution are
  estimated
• A strategy for achieving the water quality
  standard must be developed, approved, and then
  implemented

Note fact sheets
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Zumbro River Watershed TMDLs

• First round of Clean Water Legacy Act TMDL
  Development Money
• Contract with Barr Engineering
• January 2007 October 2009 timeline
• Addresses multiple listings on major watershed
  scale
• Goal Improved Water Quality in ZR Basin

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Zumbro TMDLs Results
Lower Zumbro River at Kruger Landing
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Estimated Required TSS Load Reductions

• Silver Creek 50-65
• 07040004-556 80
• Bear Creek 60-70
• Willow Creek 80
• SF Zumbro 70
• Cascade Creek 60-75
• 07040004-601 45
• Dodge Center Creek 45
• SB MF Zumbro 55-85
• Milliken Creek 55
• MF Zumbro 90
• Zumbro River nr mouth 75
• Notes
• WWTF not a significant piece of the TSS load
• MS4 component significant for some of the urban
  streams

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Source Identification

• Each TMDL lists probable TSS sources
• Point vs Non-point split is solid
• Non-point breakdown is present
• Each TMDL includes listing of probable sources

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Zumbro TMDLs

• What will happen from here on?
• Turbidity TMDLs
• April 30, 2009 First Draft
• July 15, 2009 second draft
• Sector meetings
• Public notice (review and comment) probably start
  sometime in Sept
• Turbidity TMDL results will inform lake TMDL work
• Implementation Plan
• Probably some iteration/revision of ZWP Plan
• Door open to funding
• LGUs, others manage non-point sources
• Track Progress

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Zumbro TMDL work as it Relates to Lake Shady

• Upstream issues addressed watershed management
• Lake Zumbro water budget Middle Fork rated
• Examination of historical TP, TSS loading
• Sites upstream and downstream of Lake Shady
• Useful, but not perfectly translatable
• TMDL focused on water quality standards and
  related assessment parameters/methodologies
• Lake Zumbro water quality is largely a function
  of epilimnetic conditions
• Turbidity sampling is currently focused on
  uppermost stratum of flow

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Link Watershed Management to Designated Use

• Southeast Minnesota is the heart of the states
  fertile limestone stream smallmouth and trout
  fisheries. There are 15 smallmouth streams in
  this region, and all of them could benefit from
  better landuse policies, as well as in-stream
  habitat work One stream that could really
  benefit from more attention is the Middle Fork of
  the Zumbro River. A native smallmouth stream in
  Dodge County, the Middle Fork still holds
  smallies, but targeted easements and some limited
  in-stream work could significantly reduce
  siltation and increase smallmouth habitat.
• From My Dream Better Smallmouth Fisheries,
  article by Tim Holschlag, Midwest Fly Fishing,
  July 2009, Page 13

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Lake ZumbroWater Pollutant Loads
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Water Budget
Ungauged land area, percent of wtshd total 14
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TP and TSS Loads
Preliminary Estimates Draft Only July 2009 SF
Load corroborated by continuous turbidity
regressions Percentages are high because ungauged
values not included
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Upstream Downstream of Lake Shady
Lake Shady 272,832 acres Mantorville 111,524
(41) Pine Island 82,175 (30)
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Concentration Snapshots

• Simple look at TSS and TP at various points in
  the watershed
• Hydrographs dont always match perfectly
• Can be interpreted as general indication of
  relative water quality at sampling locations as
  water moves through system
• Only grab samples not total sediment
• Rainfall variable across basin
• Sampling was focused on events

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This is not total sediment its TSS
Sample
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8/9/07 calm period
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8/19/07 SF peak, outflow and MF rising
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9/25/07 all hydrographs rising after relatively
calm period
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10/1-10/3/2007 peak and receding limb of
significant event
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After significant late September 2007 event, more
rain pushed flow up again at all three locations
10/1/2007
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5/30/08 all points rising at start of event
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6/9, 6/12 and 6/13/2008 rising limb and peak of
big event
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Load Estimates
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Lake Shady 272,832 acres Mantorville 111,524
(41) Pine Island 82,175 (30)
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23.6
Total Suspended Solids-TSS (June-08)
6,427,824 kg
Lake Zumbro
27,223,118 kg
65.6
Middle Fork
34.4
17, 870,250 kg
Lake Shady
South Fork
N Br of Middle Fork
9,352,868 kg
1,380,613 kg
6,116,115 kg
22.6
77.4
S Br of Middle Fork
4,735,502 kg
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47.6
Total Phosphorus (June-08)
22,526 kg
Lake Zumbro
47,293 kg
67.5
Middle Fork
32.5
31,938 kg
Lake Shady
South Fork
N Br of Middle Fork
15,355 kg
12,160 kg
20,589 kg
59.1
40.9
S Br of Middle Fork
8,429 kg
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Thoughts

• Can Conclude that
• TMDL monitoring does not inform total sediment
  budget, sed rates, etc. for LZ or LS
• It appears that Lake Shady does not remove much
  (if any) TSS from the MF Zumbro stored TSS is
  likely exported during major events
• The volatile fractions of the TSS entering and
  exiting the lake are approx equal
• To fully understand Lake Shadys treatment with
  respect to sediment, would likely need particle
  size info, vertically-integrated sampling
  techniques, etc.

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• If there is time
• SF historical loading
• MF Video

Justin Watkins Rochester MPCA 507.206.2621
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South Fork Zumbro River Historical Loading Data
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Data Sources

• MPCA Milestone Site
• S000-268
• 1973 to present
• 75th Street North
• 2 of 5 years, monthly
• TMDL project site
• S003-802
• 2007 and 2008
• 90th Street North
• For load work
• USGS flow gauge
• 05372995
• 1950s to present
• Instant flows only 1990-2008

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Data Summary

• Instant flow period of record does not match well
  the Milestone schedule
• Data Used
• 124 pairs, 91 for May-Sept, 114 for Mar-Oct
• 1991-2002 20 values (with 8 in 2001)
• 2003 17
• 2005-2006 8
• 2007 49
• 2008 30

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This is not total sediment its TSS
Sample
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2 ft/sec
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FLUX notes

• Flow vs concentration is based largely on recent
  data, but applied to flow record 1990-2008.
• Flow vs concentration very good and CVs very low
  for TP (0.05) and moderately low for TSS (0.09)
• No adjustments were made for 37th Street vs 75th
  Street vs 90th Street
• Simple analysis suggests that 75th and 90th
  essentially equivalent concentrations

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MPCA Milestone Trend Analysis
http//www.pca.state.mn.us/water/pubs/milestonetre
ndsbydecade.xls
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Milestone has Documented Trends
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Justin Watkins Rochester MPCA 507.206.2621
Discussion Questions
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