A water-quality investigation of the Yellowstone Riverwas conducted during low-flow conditions in August 2000,under the U.S. Geological Survey's National Water-QualityAssessment (NAWQA) program. Samples for analysis ofwater chemistry (nutrients, field measurements, and otherconstituents) and biological communities (periphyton,phytoplankton, and macroinvertebrates) were collected at11 sites on the main stem of the Yellowstone Riverbetween Corwin Springs and Sidney, Montana, as well asfrom tributaries including the Clarks Fork of theYellowstone River, the Bighorn River, and the TongueRiver.

Preliminary results of the investigation indicateconcentrations of total nitrogen varied little throughout thelength of the main stem of the Yellowstone River; totalphosphorus concentrations increased slightly in the down-stream direction. In contrast, periphyton chlorophyll a andash-free dry mass concentrations, and algal productivityrates, were highest in the middle sections of theYellowstone River.

At low to moderate concentrations, algae are an integralpart of a healthy stream ecosystem. Algae are single-celled plants that contain chlorophyll and carry outphotosynthesis. The periphyton (algae attached to rocks,logs and submerged objects) and phytoplankton (sus-pended or floating algae) are primary producers in theaquatic food chain, and provide food and habitat forinvertebrates and other organisms. During daylight, algaeproduce oxygen that is essential for aquatic life, sometimescausing the water to be supersaturated with oxygen.During the night, excessive algal growths can depletedissolved-oxygen concentrations to levels lethal to fish,

particularly trout, due to algal respiration and consumptionof oxygen through decay of dead algal cells and otherorganic matter in the water. Respiration and decay oforganic matter consume oxygen throughout the day andnight, but are offset by photosynthesis during the daylighthours. Excessive growths of algae also can be aestheti-cally displeasing, as well as a nuisance for anglers,irrigators, and other water users.

In response to nuisance growths of the green algaeand dissolved-oxygen concentra-

tions less than State of Montana standards, voluntarynutrient criteria were adopted in the Clark Fork basin ofwestern Montana (tributary to the Columbia River)(Watson and others, 2000). The nutrient criteria from theClarks Fork are presented in this paper as a point ofreference, as are the ambient water-quality recommenda-tions issued by the U.S. Environmental Protection Agency(2000a) to help the states establish nutrient criteria forcontrol of nuisance algal conditions. The EPA recommen-dations for concentrations of two causal variables,

Cladophora glomerata

total

U.S. Department of the Interior

U.S. Geological Survey

Water-Resources Investigations Report 01-4238

Cheyenne, Wyoming, 2001

View looking downstream in the Yellowstone River at

Corwin Springs (site Y1) .(photo by Greg Boughton)

CHEMICAL AND BIOLOGICAL INDICATORS OF NUTRIENT ENRICHMENT IN THE

YELLOWSTONE RIVER BASIN, MONTANA AND WYOMING, AUGUST 2000:

STUDY DESIGN AND PRELIMINARY RESULTS

OVERVIEW

Background

1

nitrogen and total phosphorus, and two response variables,, are based on ecoregions

(Omernik, 1996) to account for natural variations in waterquality; ecoregions for the Yellowstone River Basin inMontana are shown in figure 1. Nitrogen and phosphorusare considered causal variables because limited supply ofeither phosphorus or nitrogen, or both, can hinder algalgrowth, and excess supply of either nutrient, or both, canresult in excessive algal growth. The response

chlorophyll a and turbidity

chlorophyll a and turbidityvariables

are considered potentialindicators of excessive algal growth. Chlorophyll a is ameasure of algal biomass or standing crop. Turbidity is ameasurement of light penetration through a water sample,and is influenced by phytoplankton, inorganic particlessuch as clay and silt, and other materials such as dissolvedorganic matter.

The U.S. Geological Survey is conducting variousstudies in the Yellowstone River basin under the NAWQA

program (Miller and Quinn, 1997, and. The purpose of

this report is to describe the design of one of the studiesand present preliminary results. Eleven sampling siteswere located on the main stem of the Yellowstone River,spanning almost 1,000 kilometers and bracketing majortributaries (fig. 1). Sampling sites also were located on themajor tributaries near their confluence with theYellowstone River and at selected NAWQA sites (SB1,BH1, and LP1) (fig. 1). Table 1 lists the samples andmeasurements at each site; only the preliminary results aredescribed here. Additional data presentation and interpre-tation are planned to meet the objectives of this study,which are:

Evaluate the trophic condition of the Yellowstone Riverusing chemical and biological indicators ofeutrophication,

Understand sources of nutrient enrichment and biologi-cal responses associated with tributary inflows andland-use practices, and

http://wy.water.usgs.gov/YELL/index.htm

�

�Purpose and Scope

Kalispell

Helena

Study unitYellowstoneNational

Park

Cheyenne

Riverton

Billings

Fort Peck

INDEXMAP

Casper

MONTANA

WYOMING

NORTH

DAKOTA

Sampling site and number

EXPLANATION

Northwestern Great Plains

Ecoregions

Middle Rockies

Wyoming Basin

Montana Valley and Foothill Prairies

111° 110° 109° 108° 107° 106° 105° 104°

48°

47°

46°

45°

44°

Figure 1. Location of sampling sites for Yellowstone River study, August 2000. Ecoregions are based on patterns

of land use, land surface form, potential natural vegetation, and soils (modified from Omernik, 1996).

100 MILES

20 40 60 80 100 KILOMETERS0

20 40 60 800

Base modified from U.S. Geological Surveydigital data, 1:2,000,000, 1972Albers Equal-area Conic projectionStandard parallels 29°30 and 45°30� �

Yellowstone

YellowstoneLake

Bighorn

Lake

TongueRiver

Reservoir

Riv

er

River

Missouri

Clarks

Riv

er

Bigh

orn

Tong

ue

Powde

r

River

Riv

er

Shoshone

River

Fork

Boundary ofYellowstoneNational Park

Study unit boundary

MONTANA

WYOMING

MO

NTA

NA

NO

RT

HD

AK

OTABillings

Glendive

Livingston

MilesCity

Sheridan

Cody

Gillette

Y11

Y11 Y10

Y9

Y7P1

Y8

T2

Y6BH2

Y5

Y4

BH1

LP1

CF1

SB1Y1

Y3Y2

2

� Compare biological indicators of river quality in 2000with those representing water-quality conditionspresent in the mid-1970s to determine whether anychanges have occurred in the trophic condition of theYellowstone River during the past few decades.

Total nitrogen (TN) concentrations in the main stem ofthe Yellowstone River were relatively unchanged through-out the length of the river during August 2000 (fig. 2),while total phosphorus (TP) concentrations increasedslightly in the downstream direction. Most of the nutrientconcentrations shown in figure 2 exceeded

of 0.300 milligrams per liter (mg/L) TN and0.020 mg/L TP set by the Tri-State Council to control

nuisance algal growths of in the Clark ForkRiver, Montana (tributary to the Columbia River) (Watsonand others, 2000). Some of the nutrient concentrations inthe Yellowstone River also exceeded the ecoregion specificcriteria recommended by the U.S. EnvironmentalProtection Agency (2000a). For example, the TP concen-tration from the Yellowstone River at site Y1 (table 2)exceeded the proposed TP criterion of 0.015 mg/L for theMiddle Rockies ecoregion, and the TP concentration fromthe Yellowstone River at site Y2 exceeded the proposed TPcriterion of 0.010 mg/L for the Montana Valley andFoothill Prairies ecoregion. The concentrations of TN atsites Y1 and Y2 were less than the proposed criteria fortheir respective ecoregions. Other than sites Y1 and Y2,the sites on the main stem of the Yellowstone River arelocated in the Northwestern Great Plains ecoregion, whereEPA recommendations are unavailable at this time(November 2001).

Cladophora

voluntarycriteria

3

Nutrients

Soda Butte Creekat Park boundary

Yellowstone Riverat Corwin Springs

Yellowstone Rivernear Livingston

Clarks ForkYellowstone River

Bighorn River atKane

Bighorn River atmouth

Tongue River atmouth

Little PowderRiver above DryCreek

Powder River atLocate

Yellowstone Riverat Greycliff

Yellowstone Riverat Laurel

Yellowstone Riverat Billings

Yellowstone Riverat Custer

Yellowstone Riverat Forsyth

Yellowstone Riverat Miles City

Yellowstone Rivernear Terry

Yellowstone Riverat Glendive

Yellowstone Rivernear Sidney

06187915

06191500

454634109463401

SB1

Y1

Y2

Y3

Y4

CF1

Y5

Y6

BH1

BH2

Y7

T2

Y8

LP1

P1

Y9

Y10

Y11

X

X

X

X

X

X

X

X

X

X

NS

NS

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

NS

NS

NS

NS

X

X

X

X

X

X

X

X

X

X

X

NS

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X X

X

X

X

X

X

X

X

X X

X

X

X

X

NS

NS

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X X

X

X

X

X

X

X

X

NS

NS

X

X

X

06205200

06208500

06214500

06218000

06279500

06294500

06295000

06308500

06309000

06324970

06326500

06326530

06327500

06329500

06192500

Table 1. Sampling sites and measurements for ecological synoptic, Yellowstone River Basin, August 2000

[chl a, chlorophyll a; AFDM, ash-free dry mass; NS, not sampled (no flow)]

Station nameUSGS

station numberSitecode Turbidity

Lightextinction

Suspendedsediment

Periphytontaxonomy

Invertebratetaxonomy

Periphytonchl a and

AFDMNutrients

Dielmeasure-

ments

Y1(CorwinSprings)

Y2 Y4 Y5(Billings)

Y6 Y7(Forsyth)

Y8 Y9 Y10 Y11(Sidney)

CF1 BH2 T2

Figure 2. Nutrient concentrations in the Yellowstone River and selected tributaries, August 2000. Voluntary criteria for control

of nuisance algal growths in the Clark Fork River, Montana (Watson and others, 2000) are shown for reference.

0

0.010

0.005

0.015

0.020

0.025

0.035

0.030

0.040

SITE

CO

NC

EN

TR

AT

ION

,IN

MIL

LG

RA

MS

PE

RLIT

ER

Total phosphorus

Total phosphorus

voluntary criterion

0

0.2

0.4

0.6

0.8

1.2

1.0

1.4

CO

NC

EN

TR

AT

ION

,IN

MIL

LG

RA

MS

PE

RLIT

ER

Total nitrogen

Total nitrogen voluntary criterion

Clarks ForkYellowstone River

enters

Bighorn Riverenters

0.305 0.016 1.5 1.4 25.0

1.23 0.095 66 18.3 50.9

0.260 0.020 2.8 38.6 18.9

MR

WB

Y1

MVFPY2

0.34 0.015 0.5 1.42 332

3320.30 0.010 1.0 21.08

0.368 0.022 4.2 1.782 43.92

1Proposed criteria from U.S. Environmental Protection Agency (2000a)Criterion for aggregate ecoregion is shown because specific criterion is not available.2

BH1

Table 2. Proposed algal-nutrient criteria for selected ecoregions in the Yellowstone River Basin

[mg/L, milligrams per liter; NTU, Nephelometric Turbidity Units; g/L, micrograms per liter; mg/m , milligrams per square meter;

MR, Middle Rockies; MVFP, Montana Valley and Foothill Prairies; WB, Wyoming Basin]

� 2

Site Ecoregion Aug. 2000 Aug. 2000 Aug. 2000 Aug. 2000 Aug. 2000

Total nitrogen (mg/L)Total phosphorus

(mg/L)Plankton

chlorophyll a ( g/L)�Periphyton

chlorophyll a (mg/m )2Turbidity (NTU)

Proposedcriterion

Proposedcriterion

Proposedcriterion

Proposedcriterion

Proposedcriterion

1 1 1 1 1

4

The standing crop of periphytonin the Yellowstone River, as indi-cated by chlorophyll a and ash-freedry mass (AFDM) concentrations(fig. 3), was highest in the middlesegments of the river near Billings(site Y5) and Forsyth (site Y7). Thepeaks in standing crop might be areflection of inflows from the ClarksFork Yellowstone River (site CF1),which joins the main stem betweensites Y4 and Y5, and the BighornRiver, which joins the main stembetween sites Y6 and Y7. Thefilamentous green algae

was noted during thesampling at many of the sites andwas particularly abundant at sites Y5,Y7, and CF1. The chlorophyllconcentration of 797 mg/m (milli-grams per square meter) in theYellowstone River at Billings(site Y5), 114 mg/m in the ClarksFork Yellowstone River (site CF1),and 164 mg/m in the Bighorn River(site BH2) were in the range of orexceeded the 100 to 200 mg/mchlorophyll a concentration sug-gested as an indicator of nuisancealgal conditions (U.S. EnvironmentalProtection Agency, 2000b).Periphyton chlorophyll a concentra-tions from sites Y1 and Y2 were lessthan the NutrientEcoregion II proposed criterion of33 mg/m (U.S. EnvironmentalProtection Agency, 2000a).

Nutrient Ecoregion II, theWestern Forested Mountains,contains the Middle Rockies, theMontana Valley and Foothill Prairies,and other level III ecoregions in thewestern United States.

minute intervals. The linear por-tions of the diel curves (for example,

Cladophoraglomerata

2

2

2

2

2

Aggregate

Aggregate

Algal productivity and respirationwere highest in the middle segmentsof the main stem Yellowstone River.Data sondes were deployed for about48 hours at selected sites to recorddissolved oxygen and pH at15-

Algal Productivity

Algal Standing Crop

Pmax

Rmax

Figure 5. Rates of dissolved oxygen production (P ) and respiration (R ),

August 2000.max max

-0.30

-0.10

-0.20

0.20

0.00

0.10

0.30

0.40

0.50

0.60

0.70

Y1(CorwinSprings)

Y2 Y5(Billings)

Y6 Y7(Forsyth)

Y8 Y9 Y11(Sidney)

SITE

CH

AN

GE

IND

ISS

OLV

ED

OX

YG

EN

,IN

GR

AM

SP

ER

CU

BIC

ME

TE

RP

ER

HO

UR

Pm

ax Rmax

Figure 4. Diel fluctuations in dissolved oxygen concentration and pH in the Yellowstone

River at Custer, site Y6, August 26-28, 2000 (P , dissolved oxygen production, R ,

respiration).max max

5

6

7

8

9

10

11

12

1600

1800

2400

1200

1800

2400

0600

1200

1800

2400

0600

TIME

DIS

SO

LV

ED

OX

YG

EN

,IN

MIL

LIG

RA

MS

PE

RLIT

ER

AN

Dp

H,

INS

TA

ND

AR

DU

NIT

S

pH

Aug. 26 Aug. 27 Aug. 28

Dissolved oxygen

Figure 3. Periphyton chlorophyll a (chl a) and ash-free dry mass (AFDM), August 2000.

1

10

100

1,000

Y1(CorwinSprings)

Y2 Y3 Y4 Y5(Billings)

Y6 Y7(Forsyth)

Y8 Y9 Y10 Y11(Sidney)

SITE

Clarks ForkYellowstone River

entersBighorn Riverenters

Ch

la,

INM

ILLIG

RA

MS

PE

RS

QU

AR

E

ME

TE

R,

AN

DA

FD

M,

ING

RA

MS

PE

R

SQ

UA

RE

ME

TE

RChl a

AFDM

5

fig. 4) were used to estimate P (the maximum rate ofproduction) and R (the maximum rate of respiration).The highest value for P in the Yellowstone River was0.61 grams O /cubic meter/hour at site Y5 in Billings(fig. 5). The R also was highest at site Y5 (fig. 5),consistent with the highest standing crop of periphyton.

Preliminary results indicate relatively high algalstanding crop and productivity in the middle segments ofthe Yellowstone River during August 2000. Those algalfactors appear to be uncorrelated to the total nitrogen andtotal phosphorus concentrations, indicating that the algalfactors provide a more sensitive measure of nutrient influxto the system than instantaneous sampling of total nutrientconcentrations in the water column, at least for thesnapshot provided by the August 2000 data. Additionalanalyses that may help to understand the trophic status andfunctioning of the river include evaluation of seasonalnutrient data, examination of algal and invertebratecommunity structure and autecology, and study of interre-lationships of those factors with other physical andchemical factors such as turbidity and suspended sediment.

max

max

max

2

max

Miller, Kirk, and Quinn, Tom, 1997, National Water-Quality Assessment Program, Yellowstone River Basin:U.S. Geological Survey, Fact Sheet 149-97, 4 p.

Omernik, J.M., 1996, Level III ecoregions of the continen-tal United States: Corvallis, Ore., U.S. EnvironmentalProtection Agency, digital map, scale 1:250,000.

U.S. Environmental Protection Agency, 2000a, NationalNutrient Criteria Development, accessed February2001, at URL

U.S. Environmental Protection Agency, 2000b, Nutrientcriteria technical guidance manual, rivers and streams:EPA-822-B-00-002, 152 p.

Watson, V. J., Ingman, Gary, and Anderson, Bruce, 2000,Clark Fork River: Scientific basis of a nutrient TMDLfor a river of the northern Rockies U.S.Environmental Protection Agency, 2000, Nutrientcriteria technical guidance manual, rivers and streams:EPA-822-B-00-002, p. A-19 to A-24.

in

.http://www.epa.gov/OST/standards/nutrient.html

By David A. Peterson, Stephen D. Porter,Layout and final illustrations by Suzanne C. Roberts

and S.M. Kinsey

U.S. Geological Survey, WRD2617 E. Lincolnway, Suite BCheyenne, Wyoming 82001-5662

state_rep_wy@usgs.gov

Or visit our website at

For copies of this report or additional information, contact:

District Chief

Email:

http://wy.water.usgs.gov/ Printed on recycled paper

REFERENCES

Where Do We Go From Here?

Quiet water on the Yellowstone River below the mouth of the

Bighorn River.

6