Vermillion River Monitoring Network

2008 Report

Prepared for:

Vermillion River Watershed Joint Powers Organization

May, 2009

Prepared by:

Dakota County Soil and Water Conservation District

Acknowledgments: The results presented in this report would not be complete without contributions made by the following persons:

Brooke Asleson-Minnesota Pollution Control Agency

Andrea Bergman-Minnesota Department of Natural Resources

Melissa Bokman-Scott County

Cassandra Champion-Metropolitan Council Environmental Services

Kim Chapman-Applied Ecological Services, Inc.

Curt Coudron-Dakota County Soil and Water Conservation District

Dave Holmen-Dakota County Soil and Water Conservation District

Karen Jensen-Metropolitan Council

Laura Jester-Dakota County Soil and Water Conservation District

Greg Kruse-Minnesota Department of Natural Resources

Ann Messerschmidt-City of Lakeville, MN

Paul Nelson-Scott County and Vermillion River Watershed Joint Powers Organization Scott County Administrator

Brian Nerbonne-Minnesota Department of Natural Resources

Lisa Pearson-Minnesota Department of Natural Resources

Jaime Rockney-Scott Soil and Water Conservation District

Laurie Sovell-Minnesota Pollution Control Agency

Travis Thiel-Dakota County and Vermillion River Joint Powers Organization

Justin Watkins-Minnesota Pollution Control Agency

Mark Zabel-Dakota County and Vermillion River Joint Powers Organization Dakota County Administrator

Executive Summary: The Vermillion River Monitoring Network was created to collect water quality/quantity information throughout the Vermillion River

Watershed. Samples are analyzed for a variety of parameters including nutrients, bacteria, and sediment. These results are used to

establish long-term water quality and quantity data, provide trend analysis and pollutant loading values. Results for the 2008 monitoring season are compared against state water quality standards or minimally impacted stream eco-region

means, developed by the Minnesota Pollution Control Agency (Appendix A). Results in red text are exceeding state water quality

standards or eco-region means.

Although most parameters are below state standards or minimally impacted stream eco-region means, several parameters did exceed

water quality standards and/or eco-region means. Wastewater treatment plant discharge can contribute to elevated conductivity levels

and may explain the conductivity results for those sites nearest to the Elko/New Market waste water treatment plant. Since the

Vermillion River has been listed as impaired for bacteria, it is not surprising that 2008 E. coli results continued to exceed the state

standard at all locations. A region-wide Total Maximum Daily Load (TMDL) study has been completed to help address elevated

bacteria concentrations (MPCA 2006). Nitrate results were unusually high at the South Branch site, and may warrant further

investigation in view of nitrate groundwater contamination in the eastern portion of the watershed. Mean turbidity (cloudiness) results

at sites VR807 and SB802, located in the trout stream portion of the watershed, are only slightly exceeding the state turbidity standard,

but may still constitute a violation of state water quality standards.

Introduction:

The Vermillion River Watershed is one of the largest watersheds located within the Minneapolis/St. Paul metropolitan area. More

importantly, the watershed is home to a robust and thriving trout population located within two rapidly growing counties in

Minnesota. As a result, numerous water quality monitoring programs are actively assessing the health of this watershed. The purpose

of this report it to concisely summarize the results of the surface water quality monitoring activities sponsored by the Vermillion River

Watershed Joint Powers Organization (VRWJPO) and completed by the Dakota County Soil and Water Conservation District

(DCSWCD) and the Scott Soil and Water Conservation District (SSWCD).

In addition to describing results from 2008, this report includes historical water quality monitoring results from as early as 2000. The

historical results presented here are intended to describe long-term water quality trends apparent in the watershed. The level of

statistical analysis completed here is limited due to a relatively brief water quality record, and results should be considered

preliminary.

Vermillion River Monitoring Network: The Vermillion River Monitoring Network (VRMN) was created in the early 1990’s to a obtain water quality data from the Vermillion

River Watershed and initially consisted of six monitoring stations located in Dakota County. Since then, the network has grown to

include a total of eight permanent monitoring stations (Figure 1) and includes an automated weather station designed to assist with

water quality analysis in the Vermillion River Watershed.

Figure 1. Vermillion River Monitoring Network and WOMP Station Locations

In 2008, the Minnesota Pollution Control Agency (MPCA) listed the

Vermillion River as impaired for turbidity. This new listing extends

along the main channel of the Vermillion River, from Highview

Avenue in Lakeville, MN to just west of Highway 3 in Farmington,

MN. In anticipation of the forthcoming turbidity TMDL study, the

VRWJPO purchased two automated turbidity probes to supplement

existing turbidity data for the impaired reach (Figure 2). This new

equipment will allow for an improved understanding of conditions

contributing to turbidity exceedances of state water quality standards

and will aid in future TMDL load calculations.

On March 18th

of 2008, the Metropolitain Council completed a project

to re-route all Empire Wastewater Treatment Plant (WWTP) effluent,

which had been previously discharging directly into the Vermillion

River, to outlet directly into the Mississippi River, via a 13 mile long

pipeline. Although this project is likely to improve water quality

downstream from the Empire WWTP, anecdotal information suggests

that in 2008 alone, flow near the falls in Hastings was lower than it has

been in 25 years (Figure 3).

The Vermillion River Joint Powers Board continued to contract with

the Minnesota Department of Natural Resources (MNDNR) in 2008 to

assist in refining flow measurements and the data analysis necessary to

convert VRMN 15-minute stage data into 15-min flow data, which is

used by various water resource management organizations throughout

the watershed. These data are available on the Minnesota Cooperative

Stream Gaging Program website

(http://www.dnr.state.mn.us/waters/csg/index.html).

Methods:

Monthly base flow and event flow samples were collected from the Vermillion River Monitoring Network utilizing standardized

procedures outlined by the Metropolitan Council Environmental Services (Metropolitan Council, 2003). At each station, automated

equipment records stage every fifteen minutes, which is then converted to flow values through the use of MNDNR developed rating

tables. A temperature logger is also located at each station to continuously record temperature throughout the summer months.

All grab samples are transported to the Metropolitan Council Environmental Services Water Quality Lab and are analyzed according

to EPA specified protocols for various endpoints. These endpoints include standard bacterial and chemical parameters. Quality

assurance and quality control samples are reviewed annually using MPCA established data quality objectives. At the end of every

sampling season, these data are entered into the MPCA’s Environmental Data Access system and the EPA’s STORET database.

Results and Discussion: In addition to results from the Vermillion River Monitoring Network, data from the Metropolitan Council’s Watershed Outlet

Monitoring Program (WOMP) site, located on the Vermillion River in Hastings, are included to provide water quality data from the

extreme eastern portion of the watershed. This site is labeled as VR WOMP in Figure 1. Similar to the VRMN, DCSWCD staff

collect monthly low flow samples, event grab samples, and event composite samples from this location.

Results presented in the following graphs extend from the western-most site, located in Scott County, to the Metropolitan Council’s

Watershed Outlet Monitoring Program site, located in Hastings. The various graphs describe monitoring site data with the

westernmost sites on the left side of the graphs and easternmost sites on the right side of the graphs (Figures 5-8 and 10-13). Results

include flow, precipitation, nutrient, turbidity, temperature, and E. coli (bacteria) data.

Results are typically presented as an arithmetic or geometric mean and are compared against mean values for minimally impacted

streams of the Western Corn Belt Plains ecoregion, published by the Minnesota Pollution Control Agency (MPCA) (McCollor and

Heiskary, 1993). The Western Corn Belt Plains ecoregion was selected since the majority of the Vermillion River Watershed is

located within this ecoregion. Results are also compared against State Water Quality Standards (Minnesota Statute 7050) where

appropriate. Stream temperature data are compared against optimal temperatures for adult brown trout (Bell, 2006).

Figure 3. 8/30/08-Low flow conditions at

Vermillion River Falls in Hastings, MN.

Figure 2. DCSWCD staff install automated turbidity

monitoring equipment.

Comparisons with ecoregion mean data and state standards are simple and are only intended to be used as a coarse method to identify

water quality exceedances. These analyses are not intended to be a definitive determination of water quality impairment. Assessment

of impairment is completed bi-annually by the MPCA using a more comprehensive process and assessment methods.

Flow and Precipitation

Mean daily flows and precipitation data for the 2008 sampling season are presented in Figure 4. Flow and precipitation results are

similar to those observed in recent years, with the exception VR803 and VR WOMP flow results. As mentioned above, the

Metropolitan Council re-routed the Empire Wastewater Treatment Plant discharge from the Vermillion to the Mississippi River in

March of 2008. As a result, volumes at the downstream sites, VR803 and VR WOMP, were reduced from previous years. In fact, the

lowest mean daily flow for station VR803, over the entire history of the VRMN, occurred in 2008. Mean daily flow on August 26th

,

2008 was 29.7 cfs. The next lowest recorded VR803 mean daily flow occurred on October 2nd

, 2003 at 41.7 cfs. In addition, volume

at the VR WOMP station was so low that water stopped flowing over the Hastings dam in the end of August, which has never been

observed by ConAgra employees working at the adjacent plant.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0

50

100

150

200

250

300

350

400

4/1

/2008

5/1

/2008

5/3

1/2

008

6/3

0/2

008

7/3

0/2

008

8/2

9/2

008

9/2

8/2

008

10/2

8/2

008

Pre

cip

itatio

n (in

ch

es

)

Flo

w (c

fs)

Date

Precipitation (in.)

V24

VR809

SC804

VR807

NC808

MC801

SB802

VR803

VR WOMP

Figure 4. 2008 Vermillion River Monitoring Network and WOMP Flow and Precipitation Results

Total Phosphorus

Total phosphorus is a common

indicator of overall water quality

for surface waters and is included

here for a similar purpose. Total

phosphorus concentrations in

2008 (Figure 5) were below the

Western Corn Belt plains

minimally impacted stream eco-

region mean. Sites V24 and

VR809 are located downstream

from the Elko/New Market

Wastewater Treatment Plant,

which likely accounts for a

portion of the elevated total

phosphorus concentrations.

Historical total phosphorus results

are presented in Figure 6. Total

phosphorus concentrations in

surface waters are often driven by

precipitation events. With fewer

large rain events in 2006-2008, it

is not surprising that total

phosphorus concentrations appear

to have decreased. In addition,

the Metropolitan Council

upgraded the Empire wastewater

treatment plant in early 2006,

which likely accounts for a

portion of the apparent decrease in

phosphorus concentrations

observed in 2006-2007. With the

Empire wastewater treatment

plant effluent re-routed to the

Mississippi River in 2008,

average total phosphorus

concentrations continued to

decrease at downstream

monitoring locations.

Figure 6. Historical Mean Total Phosphorus Results

0

0.05

0.1

0.15

0.2

0.25

0.3

V24 VR809 SC804 VR807 NC808 MC801 SB802 VR803 VR WOMP

To

tal P

ho

sp

ho

rus

(m

g/L

)

Monitoring Station

Base Flow Mean

Event Flow Mean

Overall Mean

Eco-region Mean

Figure 5. 2008 Mean Total Phosphorus Results

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

2000 2001 2002 2003 2004 2005 2006 2007 2008

To

tal P

ho

sp

ho

rus

(m

g/L

)

Monitoring Station

VR24 Mean

VR809 Mean

SC804 Mean

VR807 Mean

NC808 Mean

MC801 Mean

SB802 Mean

VR803 Mean

Eco-Region Mean

Nitrates Nitrate concentrations were also

below the minimally impacted

stream eco-region mean, with the

exception of site SB802 (Figure

7). Concentrations here may be

the result of a combination of

nitrate sources including

agricultural runoff and various

groundwater inputs. However, it

should be noted that nitrate

concentrations at site SB802 were

the highest in the watershed, and

the source of these elevated results

remains unknown. Furthermore,

the MPCA has begun to assess

designated trout streams to ensure

they are below the 10 mg/L

drinking water standard. Within

the Vermillion River Watershed,

water quality data from the South

Branch site is the only data

approaching this standard and may

ultimately result in a TMDL,

should nitrate concentrations

exceed this standard in the near

future.

When 2008 nitrate concentrations

are plotted against historical

annual means, a trend in nitrate

concentrations is beginning to

emerge. Since 2006, nitrate

concentrations have continued to

rise at the South Branch/SB802

monitoring location (Figure 8).

Nitrate pollution is typically not

associated with runoff events and

concentrations often appear more

elevated under lower flow

conditions. This is likely the

result of a more chronic source of

nitrates in the South Branch sub-

watershed. If volumes in the river

are even more reduced during a

dry year, the nitrate concentrations

resulting from a chronic source

may appear even greater. Since

2008 was a relatively dry year, it

is not surprising that nitrate levels

are higher than the historical

record. However, this pattern

only appears in the SB802 data

set. Nitrate concentrations at all

other sites are roughly consistent,

or show a decreasing trend, when

compared against the historical

record.

0

1

2

3

4

5

6

7

8

V24 VR809 SC804 VR807 NC808 MC801 SB802 VR803 VR WOMP

Nit

rate

(m

g/L

)

Monitoring Station

Base Flow Mean

Event Flow Mean

Overall Mean

Eco-region Mean

Figure 7. 2008 Mean Nitrate Results

0

1

2

3

4

5

6

7

8

2001 2002 2003 2004 2005 2006 2007 2008

Nit

rate

(m

g/L

)

Year

VR24 Mean

VR809 Mean

SC804 Mean

VR807 Mean

NC808 Mean

MC801 Mean

SB802 Mean

VR803 Mean

Eco-Region Mean

Figure 8. Historical Mean Nitrate Results

Pollutant Yields

Nitrate and total phosphorus pollutant loads for each monitoring station and/or associated tributary (Figure 9) were calculated using

the FLUX stream load computation tool (Walker, 1988) for the 2008 monitoring season (March-November). A pollutant load is the

total mass of a particular pollutant that flows through a monitoring station over a given period of time. Calculated loads are divided

by the area of the associated sub-watershed for each monitoring station/tributary to provide pollutant load per acre or a pollutant yield

(Table 1). This type of analysis allows for a comparison of pollutants produced per unit area, regardless of total watershed size,

among various sub-watersheds.

Figure 9. Monitoring Site Sub-Watersheds

Table 1. 2007-2008 Pollutant Yields for the Vermillion River Monitoring Network

Sub-Watershed

(Associated Monitoring Station)

2007 NO3 Yield

(kg/acre)

2008 NO3 Yield

(kg/acre)

2007 Total Phosphorus

Yield (kg/acre)

2008 Total Phosphorus

Yield (kg/acre)

Main Channel at 220th St. (SC804) 0.28 0.97 na 0.036

Main Channel at Denmark Ave. (VR807) 0.62 0.96 0.032 0.045*

South Creek 1.18 0.95 na 0.060*

Middle Creek 0.28* 0.59* 0.029 -0.026*

North Creek (NC808) 0.24* 0.34* 0.022 0.056

South Branch Vermillion River (SB802) 2.06 2.83 0.037 0.095*

Main Channel at Goodwin Ave. (VR803) 1.88 1.36 0.067 0.035

*indicates poor FLUX diagnostic results for calculated pollutant load

Nitrate yields for 2008 were highest for the South Branch Vermillion River sub-watershed (Table 1). The South Branch sub-

watershed nitrate yield, which is of similar size and similar land use as the sub-watershed monitored at 220th

Street (SC804), was

roughly three times larger than the yield at 220th

Street. Additional monitoring may be needed to aid in determining the source of

nitrates in the South Branch sub-watershed. Nitrate yield was somewhat elevated for the main channel at Goodwin Avenue, but this is

expected as the VR803 monitoring station is located just downstream from the City of Vermillion’s wastewater treatment facility.

Total phosphorus yields for 2008 were relatively consistent across the watershed and among the various tributaries. The total

phosphorus yield for the South Branch of the Vermillion River was the highest in the watershed. However, diagnostic tests indicate

that the FLUX load estimate for this site are not statistically sound, and these value should be treated with some suspicion.

Turbidity

Turbidity results for 2008 varied

throughout the watershed (Figure

10). Turbidity during base flow

conditions remained well below

the state standards for all sites.

However, during larger

precipitation events, turbidity was

substantially elevated, often

exceeding state standards. Also,

it should be mentioned that 2008

turbidity analysis, for all samples,

was conducted by the

Metropolitan Council

Environmental Services

laboratory which records turbidity

in nephelometric turbidity ratio

units, which are not in the same

units as state water quality

standards (nephelometric

turbidity units). This problem is

not exclusive to the Metropolitan

Council Environmental Services

laboratory and will likely be

addressed by state agencies in the

near future.

Turbidity results are somewhat

variable over the period of record

(Figure 11). Results from 2008

are within the range of previous

years.

0

5

10

15

20

25

30

V24 VR809 SC804 VR807 NC808 MC801 SB802 VR803 VR WOMP

Tu

rbid

ity

(N

TR

U)

Monitoring Station

Base Flow Mean

Event Flow Mean

Overall Mean

Cold Water Standard

Warm Water Standard

Figure 10. 2008 Mean Turbidity Results

Figure 11. Historical Mean Turbidity Results (Cold water turbidity standards

apply only to stations on the trout stream portion of the Vermillion River-SC804,

VR807, NC808, MC801, SB802)

0

5

10

15

20

25

30

35

40

45

2001 2002 2003 2004 2005 2006 2007 2008*

Tu

rbid

ity

(N

TU

)

Monitoring Station

VR24 Mean

VR809 Mean

SC804 Mean

VR807 Mean

NC808 Mean

MC801 Mean

SB802 Mean

VR803 Mean

Warm Water State Standard

Cold Water State Standard

Temperature

The Minnesota Department of Natural Resources (MNDNR) has been very active in monitoring stream temperatures in the Vermillion

River Watershed. Since 2005, the DCSWCD has been assisting the MNDNR with temperature monitoring to help delineate the trout

stream designation on the Vermillion River. In addition, the VRWJPO was awarded an EPA Targeted Watershed Grant in 2005.

Identifying and describing the way in which groundwater and anthropogenic inputs are influencing the temperatures of the Vermillion

River, was among several goals specified in this grant. Stream temperature results presented here are a compilation of data resulting

from both MNDNR and the EPA Targeted Watershed Grant efforts.

Automated temperature loggers were placed at each of the VRMN stations, and water temperature was recorded at 15-minute

intervals. Mean temperatures for the period of 6/2-9/2 were then plotted and are shown in Figure 12. Results from 2008 are plotted

adjacent to 2005, 2006, and 2007 temperatures for the same reference period. According to a recent literature review, the adult brown

trout chronic (long-term) exposure temperature limit is approximately 64 F (Bell, 2006). Average temperatures at most monitoring

stations, especially those in the trout stream portion of the Vermillion River (SC804, VR807, NC808, MC801, SB802) were near the

64 F threshold.

It appears that temperatures were generally higher in 2006 than in other years. Likely explanations include slightly higher ambient air

temperatures and large construction de-watering projects in the Middle and North Creek area in 2005, 2007-2008. De-watering

projects remove cool groundwater and discharge those waters to area streams. It should also be noted that the temperature logger at

site VR809 was out of the water for much of the 2006-2008 summer months, and as a result the reported mean temperature is based on

a smaller dataset than at other sites. This site appears to be located very near the surface water/ground water interface and frequently

runs dry throughout a typical monitoring season.

45

50

55

60

65

70

75

80

85

90

VR809* SC804 VR807 NC808 MC801 SB802 VR803

Te

mp

era

ture

(F

)

Monitoring Station-Vertical bars indicate temperature range (*small annual sample size)

2005 Summer Mean Temperature

2006 Summer Mean Temperature

2007 Summer Mean Temperature

2008 Summer Mean Temperature

Max. Optimal Temperature for Adult Brown

Trout

Figure 12. Historical Mean Temperature Results

Escherichia coli

Escherichia coli concentrations for 2008

within the Vermillion River Watershed

continue to exceed the state standard

(Figure 13). Precipitation event samples

produced the most elevated results.

Possible explanations for base flow results

include septic system discharge,

agricultural runoff, livestock in streams,

urban runoff, and re-suspension of

sediment bacteria.

In 2007, the MPCA recommended that

DCSWCD/SSWCD staff discontinue using

fecal coliform as a bacterial endpoint.

This was suggested in anticipation of a

change in Minnesota water quality Rules

7050. Since 2007, the DCSWCD has only

been collecting E. coli bacteria samples

from the Vermillion River Monitoring

Network, and for this reason no historical

analysis is available.

Conclusions and Suggestions for Future Monitoring: The VRMN was initially designed to aid in pollutant load calculations for monitoring stations located throughout the watershed. This

type of monitoring strategy includes collecting storm event and base flow grab samples and is particularly useful when completing

TMDL study activities. As an impaired waterway, Vermillion River monitoring data will be used in future TMDL studies and other

water quality modeling activities. However, results from this current monitoring program are also submitted to the MPCA annually

and are routinely used to determine if the Vermillion River, or its tributaries, are meeting water quality standards. Since

approximately half of these samples submitted for assessment are comprised of storm samples, and storm events are relatively short-

lived in the watershed (Figure 4), a bias towards less favorable water quality conditions may be present in the current and historical

dataset. A more appropriate monitoring strategy might include regularly scheduled sampling, in addition to storm event samples.

Using this technique, data would remain suitable for load calculations and TMDL modeling activities, and likely be more appropriate

for assessment purposes.

Nitrate concentrations within the South Branch of the Vermillion River continue to be problematic. Mean nitrate concentrations

exceed eco-region means and appear to be increasing on an annual basis (Figure 8). This could be the result of reduced rainfall in

recent years, but may also indicate an increase in nitrate contributions to the South Branch. If concentrations continue to rise and ever

exceed 10 mg/L, even for one sample, the MPCA may list the South Branch as impaired for nitrates which wil require that a TMDL

study be completed on this sub-watershed. The VRWJPO may want to consider developing a strategy (increased incentives for

conservation practices) to minimizing nitrate concentrations in the South Branch sub-watershed.

0

200

400

600

800

1000

1200

1400

V24 VR809 SC804 VR807 NC808 MC801 SB802 VR803 VR WOMP

E. c

oli (

MP

N/1

00

mL

)

Monitoring Station

Base Flow Geomean

Event Flow Geomean

Overall Geomean

State Standard

Figure 13. 2008 Geometric Mean E. coli Results

References: Bell J.M., 2006. The Assessment of Thermal Impacts on Habitat Selection, Growth, Reproduction, and Mortality in Brown Trout

(Salm trutta L): A Review of the Literature. Prepared for the Vermillion River EPA Grant #WS 97512701-0 and the Vermillion River

Joint Powers Board. Applied Ecological Services, Inc.

McCollar S., and Steve Heiskary, 1993. Selected Water Quality Characteristics of Minimally Impacted Streams from Minnesota’s

Seven Ecoregions. Addendum to: Descriptive Characteristics of the Seven Ecoregions of Minnesota.

Metropolitan Council Environmental Services-Quality Assurance Program Plan: Stream Monitoring (2003). Metropolitan Council. 5

Feb. 2007 http://www.metrocouncil.org/Environment/RiversLakes/Streams/Stream%20Monitoring%20QAPP_Final.pdf

Minnesota Pollution Control Agency, 2006. Revised Regional Total Maximum Daily Load Evaluation of Fecal Coliform Bacteria

Impairments in the Lower Mississippi River Basin in Minnesota.

Appendix A. 2008 Water Quality Data Summary

Monitoring Sites

Vermillion

River and

Cty. 46

(Scott Co.)

(V24)

Vermillion

River and

235th St.

(VR809)

Vermillion

River and

220th St.

(SC804)

Vermillion

River and

Denmark Ave.

(VR807)

Middle Creek

and Hwy. 3

(MC801)

North Creek

and Hwy. 3

(NC808)

South Branch

Vermillion

River and

Cty. 66

(SB802)

Vermillion

River and

Goodwin Ave.

(VR803)

2008 Notes

Pa

ram

ete

rs (

sta

te s

tan

dard

/ec

o-r

eg

ion

mea

n)

Mean Alkalinity 282 mg/L 241 mg/L 232 mg/L 226 mg/L 228 mg/L 218 mg/L 189 mg/L 218 mg/L Typical for

freshwater

Mean Conductivity

(698 mMHOs) 1670 mMHOs 727 mMHOs 606 mMHOs 639 mMHOs 659 mMHOs 661 mMHOs 541 mMHOs 642 mMHOs

Above eco-region

mean downstream

from Elko/New

Market wastewater

treatment plant

Mean Dissolved Oxygen 10.39 mg/L 9.11 mg/L 8.91 mg/L 8.38 mg/L 8.01 mg/L 8.52 mg/L 9.07 mg/L 9.49 mg/L Adequate for trout

fishery

Geometric Mean E. coli

(126 MPN/100ml)

583

MPN/100mL

173

MPN/100mL

220

MPN/100mL

274

MPN/100mL

175

MPN/100mL

168

MPN/100mL

245

MPN/100mL

210

MPN/100mL

Exceeding state

standard at all sites

Mean Nitrate

(NO2+NO3=4.8 mg/L) 2.31 mg/L 1.11 mg/L 2.20 mg/L 2.37 mg/L 1.31 mg/L 1.20 mg/L 6.61 mg/L 4.21 mg/L

Exceeding eco-

region mean on

South Branch at

Cty. 66

Mean Nitrogen

Ammonia

(0.4 mg/L)

0.04 mg/L 0.05 mg/L 0.03 mg/L 0.03 mg/L 0.04 mg/L 0.04 mg/L 0.03 mg/L 0.07 mg/L Below eco-region

mean

Mean Total Phosphorus

(0.28 mg/L) 0.23 mg/L 0.13 mg/L 0.06 mg/L 0.08 mg/L 0.07 mg/L 0.09 mg/L 0.09 mg/L 0.09 mg/L

Below eco-region

mean

Mean pH

(6.5-8.5) 8.17 8.21 8.33 8.21 8.19 8.09 8.24 8.21

In compliance

with state standard

Mean Total Suspended

Solids

(45.3 mg/L)

17.8 mg/L 17.5 mg/L 9.3 mg/L 28.3 mg/L 12.4 mg/L 24.1 mg/L 13.1 mg/L 16.5 mg/L Below eco-region

mean

Mean Summer

Temperature

(64 F)

67.4 F 68.2 F 65.9 F 64.7 F 60.4 F 60.1 F 64.6 F 69.1 F Slightly elevated

for trout fishery

Mean Turbidity

(10 NTU) 10.4 NTRU 11.5 NTRU 7.9 NTRU 11.4 NTRU 7.8 NTRU 9.2 NTRU 11.0 NTRU 10.5 NTRU

Exceeding state

standard at some

trout stream sites

mg/L = milligrams per liter or parts per million (ppm)

mMHO = micromhos or microseimens

MPN = most probable number

F = degrees Fahrenheit

NTRU = nephelometric turbidity ratio units