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Aquatic surveys and assessment within the Middle Powder River watershed (Volume 2006) online

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Aquatic Surveys and Assessment within the Middle
Powder River Watershed

Prepared for the Bureau of Land Management, Miles City FO
ESA010009 Task Order #28


David M. Stagliano

Aquatic Ecologist

April 2006



Natural Resource Information System
Montana State Library

Aquatic Assessment Executive Summary

Project goals of the Aquatic Surveys and Assessment of the Middle Powder Watershed were to:
1) set up integrator sites, 2) assess aquatic community baseline data, 3) identify and interpret key
watershed indicators (against reference condition standards) to determine aquatic condition status
and trends before the development of CBM wells in the immediate watershed (Pers. comm. with
Joseph Platz, 3/5/2005). This report represents the local reach-scale, aquatic portion of the larger
watershed assessment that will use an ecological community context to help qualify watershed
health and to identify focal concerns in the region. Inventory work occurred on BLM lands
where possible to enable informed management decisions at a watershed planning scale.
Fish, water quality parameters, habitat and macroinvertebrate samples were taken at 5 mainstem
Powder River and one tributary site in the Middle Powder Watershed in Montana for this BLM
assessment. One mainstem site was sampled twice temporally for fish and an additional
macroinvertebrate sample was collected from a spring- supported reach of Bloom Creek.

Macroinvertebrate Communities: Overall, 59 taxa were reported from all mainstem sites.
Average macroinvertebrate taxa richness per site was 23.4. Paired macroinvertebrate samples
taken at each mainstem site using two EMAP sampling protocols were in agreement for ranking
all five Powder River sites as non-impaired, with the DEQ MMI index scores >37. However, the
two protocols yielded very different community composition measures and the within-site
sampling method variability was greater than similar-method across site variability. Within-site
percent and taxa similarity values between the two EMAP protocols were low and ranged from
40% to 77.6%. To achieve less site/protocol-influenced variability, higher macroinvertebrate
numbers and consistency in future biomonitoring, we recommend the EMAP Targeted-Riffle
Protocols. Although, the Reach- Wide EMAP samples did pick up 2 of the 5 species of rare
sand-dwelling mayflies not sampled with the Targeted-Riffle Protocols.

Fish Communities: Fish surveys were accomplished using the 300m seining protocols
developed by Bramblett (2003) for MT Fish, Wildlife and Parks. This protocol seemed to cover
most macrohabitats in a reach, but due to the large size of the Powder, rarely encompassed more
than one series of riffle/run/pools. Overall, we captured and identified 1299 individuals of 13
fish species (1 1 natives). Native fish averaged 7 species per site (7.5 is the expected reference
condition), and 2 sites had the exotic carp and introduced plains killifish, respectively. Fish
communities scored relatively low using the IBI (averaging 59.5-fair integrity range), but when
using the derived Observed vs. Expected (O/E) values, 4 of 5 sites fell within the 1.2-0.8
unimpaired/good community threshold ranking, one was on the border (0.8) and Site 6 showed
some impairment in the community with an O/E of 0.66. The fish O/E scores also correlated
with the MMI scores across sites better than the IBI. The Sturgeon Chub, a MT species of
concern, was only collected at one site and only represented 2 individuals. We recommend
including at least 2 riffle/run complexes (skip portions of long monotonous sand reaches) in the
300m seining and using the O/E scores for integrity analysis.

Community Integrity results from the fish, habitat and macroinvertebrate surveys combined to
rank the Powder River reach upstream of Rough Creek (Site 5) the most biologically intact,
followed by the Powder River reach @ the Wyoming border (Site 1) and Site (2), the Dry Creek
reach. We recommend choosing these as integrator and future monitoring sites.


We would like to thank The Montana State Office of the Bureau of Land Management (BLM),
especially Gayle Sitter, and Joe Platz of the Miles City Field Office for support and funding for
the Aquatic Program of the Montana Natural Heritage Program. This project was also partially
funded by the ongoing BLM Watershed Assessment Project.

We wish to thank those who assisted us with this project in the water, including field help from
Coburn Currier, Support Biologist of the MTNHP and Trixi B. Smith, volunteer helper from
Michigan State University. Additional on-site field and logistics help were supplied by Linda
Vance and Greg Kudray.
All photos in the report were taken by MTNHP personnel, unless otherwise noted.

Table of Contents

Introduction 5

Study Sites 6

Study Site Map 7

Methods 8

Habitat and Water Quality Collection 8

Fish Communities 9

Macroinvertebrate Communities 10

Results and Discussion 11

Habitat and Water Quality Results 11

Fish Community Analysis 12

Macroinvertebrate Communities 16

Conclusions and Recommendations 18

Literature Cited 19

Appendix A. Raw data and IBI metric calculation from fish data collected from Middle Powder


Appendix B. Frequencies of fish species occurrence (F of O) across different segments of the

Powder River. All sites includes 2 Wyoming sites @ river mile 225 and 235, all MT sites

includes from river mile 220 to the confluence with the Yellowstone

Appendix C. Macroinvertebrate taxa list and abundance at each site, and plains MMI calculation


Appendix D. Macroinvertebrate protocol comparisons with Percent Community Similarity and

Taxa Similarity per site.

Appendix E. Fish and Macroinvertebrate Community Group Descriptions

List of Figures

Map 1. Aquatic Sample sites in the Middle Powder River Watershed 7

Figure 1 . Seining the Powder River near the WY border 8

Figure 2. Kick Seining a riffle on the Powder River 8

Figure 3. Fish IBI and O/E comparisons at the Powder River sites. Sites 5tl & 5t2 are June and July

samples at Site 5, respectively 13

Figure 4. Cluster analysis of relativized macroinvertebrate abundance data taken with the two EMAP

protocols 16

Figure 5. Relationship between the habitat scores, Fish O/E and the macroinvertebrate MMI index scores.
Impairment thresholds are lines @ 0.8 (O/E) and 37 (MMI) 17

List of Tables

Table 1 . Fish metrics and classification of fishes captured on the Powder River (2005) 9

Table 2. Impairment determinations from the MMI and O/E (RIVPACS) models 10

Table 3. Habitat quality scores, physical & water quality parameters of Middle Powder River sites 11

Table 4. Fish collected from the mainstem Powder River, IBI and O/E index scores 12

Table 5. Temporal variability in fish samples from Site 5 12

Table 6. Powder River fish samples @ the Wyoming border taken 30 years apart 14

Table 7. Cumulative species list and percentage of site occurrences of fish collected on the main-stem
Powder River in Montana (0-220 river miles). Asterisk (*) indicates fish species that have not been

collected since the 1970' s collections 15

Table 8. Overall macroinvertebrate results, sample date, percent sub-sampled, total taxa richness, number
of individuals in the sample, multimetric index score, and impairment status for each stream site 16


The Powder River is a vast drainage representing one of the last undammed, large prairie river
systems in the United States. In this part of southeastern Montana, the landscape through which
the Powder flows resembles a virtually natural condition- state of a large prairie river with
sweeping meanders across the valley bottom, side channels, oxbows, shifting islands and
functional connectedness to the floodplain. The Powder River aquatic ecosystem supports many
elements of community function and biological diversity associated with its physical setting,
including 25 native fish species (19 in Montana) and numerous species of rare invertebrates.
With its specialized aquatic life, the Powder River supports not only a diverse community but
represents the sole remnant of a once widespread Great Plains riverine community of fish and
invertebrates (Hubert 1993). Prairie rivers and streams are one of the most understudied and
endangered aquatic systems in North America (Dodds et al 2004). Furthermore, the Powder
River provides substantial habitat for the declining sturgeon chub (MTSOC, species of concern),
a species that has been extirpated from much of its historic range (Werdon 1994). In Wyoming,
the Powder River was identified by Patton et al. (1998) as supporting an abundance of species
adapted to turbid rivers (the flathead chub, Platygobio gracilis', plains minnow, Hybognathus
placitus\ western silvery minnow, Hybognathus argyritis\ river carpsucker, Carpoides carpio,
and the channel catfish, Ictalurus punctatus) that have been greatly reduced or eliminated from
other drainages. In a previous report, Stagliano (2005) identified the Powder River as the
reference standard in its Large Prairie River classification; no other large prairie system in the
ecoregion contains the quality and biological integrity of its communities and habitats. The
Powder River has been identified as the primary spawning area for the lower Yellowstone River
sauger (MTSOC) population (Rehwinkel 1978), as well as other species that migrate from the
Yellowstone River to these tributaries to spawn (the blue sucker (Cycleptus elongatus),
shovelnose sturgeon (Scaphirhynchus platorhynchus), burbot, and channel catfish)(Backes 1994,
Riggs and Gardner 2000).

The invertebrate communities in the Powder River are as rare and specialized as the fishery.
Rehwinkel (1978) concluded that the Powder River supported the most unique community of
benthic invertebrates in Montana. More recent investigations (2000-2002) by Dan Gustafson
(pers comm. 01/12/2006) and this study (2005) indicate that some of these specialized mayflies
(Ephemeroptera) are not only rare, but are in decline. Six of these globally rare to uncommon
mayfly species (Analetris eximia, Anepeorus rusticus, Raptoheptagenia cruentata, Ametropus
neavei, Homoeoneuria alleni, Lachlania saskatchewanensis) will now be included on the 2006
Montana species of concern list (unpublished, Montana Natural Heritage Program 2006). These
species were probably once quite common in prairie rivers in the northern Great Plains, but have
been eliminated throughout most of their historic range due to impoundments and other
anthropogenic river alterations.

The Powder River Basin in Wyoming and Montana is currently undergoing one of the world's
largest coalbed natural gas (CBNG) developments with about 12,000 wells in place in 2003,
14,200 in 2005, and up to 70,000 projected over the next 20 to 30 years (Davis and Bramblett,
2006). Coal bed methane mining has the potential to severely disrupt the ecosystem and harm its
biota, both in the riparian zone and within the stream itself. The interconnectedness of rivers
with their watershed renders any lotic ecosystem vulnerable to threats from human activities

anywhere in the landscape (Allan et al.l997). Numerous aquatic and fisheries professionals have
commented on the consequences of CBM mining within the watershed in an EIS report to the
BLM. See expert evaluations at allan.shtml for
potential ecological consequences of unrestricted CBM development within the immediate
watershed. A recent aquatic task group (ATG) was convened by the BLM to address some of the
monitoring and research issues and will undoubtedly perform rigorous scientific investigations
before proceeding on a path that will endanger a rare ecosystem.

Powder River Sites

Per conversation with Joe Platz (5/5/2005), we chose sites along the main-stem Middle Powder
River with BLM in-holdings that were easily accessible and would complement USGS
monitoring sites (see Map 1):

1) *Large parcels upstream of Moorhead near the WY border where Bradshaw, Bitter and
Dry Creeks enter the Powder (either side access, 2 reaches).

2) Downstream of Moorhead where Jenkins Creek enter the Powder (south side access).

3) ^Across and downstream from where Bloom Creek enters the Powder (south-side access.
Buttermilk Creek).

4) Upstream from where Rough Creek (north) enters the Powder (north-side access)

Site No.




Elev (ft)


Powder River 1

Powder River @ WY border





Powder River 2

Powder River @ Dry Creek





Powder River 3

Powder River @ Jenkins Creek





Powder River 6

Powder River @ Buttermilk Creek





Powder River 5tl

Powder River ups Rough Creek





Powder River 5t2

Powder River ups Rough Creek





Bloom Creek

downstream Hailstone Spring





Joe Platz and I did site recon in early June and established the 5 mainstem Powder River reaches
(with GPS points, flagging and site photos at the 0, 300 and 450m points). Numerous tributary
sites on BLM lands were visited (-19 stream miles) in the watershed for possible lotic sampling,
but were consistently dry. Intermittent Prairie Stream reaches that were visited, but not sampled,
included Bitter, Buttermilk, Jenkins, Rough (north & south), Buffalo, Dry and Maverick Prong
of Bloom Creek (see Map 1). One mainstem site (166.2 RM, Site 5 near Rough Creek) was
sampled twice temporally for fish.


Aquatic communities (fish & macroinvertebrates) and riparian areas were inventoried and
assessed using a combination of FWP (fish) and BLM / EPA (macroinvertebrates and habitat
assessments) protocols and methodology. Reach lengths were set as a standard 300m, but to
encompass an additional set of riffle macrohabitats for the macroinvertebrate targeted-riffle
sampling protocols were extended to 450m. Information and results from previous inventories,
such as those conducted by FW&P (fish) and the BLM (e.g. PFC Lotic riparian areas) will be
integrated into the final Watershed Assessment report. This report will provide a valuable
baseline of current watershed health and recommendations for future monitoring efforts.

Map 1 . Aquatic sample sites in the Middle Powder River Watershed.

Sample Sites in the
Middle Powder Watershed



Middle Powder Watershed
^^ Streams
• Sample Sites


Bureau of Reclamation

US Fish and Wildlife Service

National Park Service

US Porest Service

other USD A (ag research stations)
I Army Corps of Engineers
I Other Department of Defense

Undifferentiated state

DNRC{state trust lands)

10 Kilometers

Montana Fish, Wildlife & Parks

University, Institutions, MDT
DNRC (water project lands)
Local Government
Bureau of Indian Affairs Trust
Tribal Lands
Undifferentiated Private
Plum Creek
Pnvate Land Trusts

Habitat and Water Quality Collection and Analysis

A visual rapid habitat assessment (Barbour et al. 1999) based on 10 habitat variables
(instream fish cover, epifaunal substrate, pool substrate characterization, pool variability, channel
alteration, sediment deposition, channel sinuosity, channel flow status, bank condition, bank
vegetative protection, riparian vegetated zone width) was completed for each sampled reach. The
habitat quality scoring is based on a maximum score of 200. Additional physical habitat:
channel wetted width (in meters), channel depths recorded at Va, Vi and % wetted width at all
transects (in centimeters), and substrate (in % size-class coverage per transect) based on
WoUman size-classes were measured at 10 transects spaced 30 meters apart perpendicular to the
stream channel. Specific conductivity, pH, water temperature and dissolved oxygen
concentration were measured on-site prior to biological sampling with a Yellow Springs
Instruments, Inc. model 85 water quality meter calibrated to the higher conductivity level.

Fish Collection and Analysis

Fish surveys were performed using the 300m seining protocols developed by Bramblett (2003)
for MT Fish, Wildlife and Parks. This protocol calls for block nets at the upstream and
downstream ends of the reach, but the width of the Powder River precluded the use of these.
Instead, shallow riffle areas were used as barriers and probably sufficient to prevent fish from
escaping while the run & pool areas were being seined (Figure 1). Shallow riffle areas unable to
be seined in the normal fashion because of rock obstructions were "kick-seined" (Figure 2) to
capture fish inhabitating this macrohabitat. We used 30ft, Va inch mesh seines to cover most
areas across the channel and all macrohabitats within the reach. Fish were transferred to holding
buckets, identified to species, enumerated in the field, examined for external anomalies (e.g.
deformities, eroded fins, lesions, and tumors), and then released. Young-of-the-year fish less
than 20 millimeters in length were noted on the field sheet (not included in the totals), and
released. Voucher specimens were only taken in the case of uncertain field identifications of the
silvery minnows, Hybognathus spp., which were preserved in 10% buffered formalin and
identified in the lab. Vouchers will be submitted to the Montana State University fish collection.

Figure 1. Seining the Powder River @ the WY border

Figure 2. Kick Seining a riffle on the Powder River

Analysis of the sampled fish communities used Integrated Biotic Indices (IB I) (Bramblett et. al
2005) and derived Observed/Expected (O/E) Fish Models (Stagliano 2005) to detect impairment
in the biological integrity of the sites. The IBI involved calculation of a series of metrics

evaluating different attributes of the community (Table 1). Because fish taxa richness is
expected to be directly proportional to watershed size, we used an average catchment area for
this reach (20,962 km^) based at the Moorehead gaging station. The metrics allowed calculation
of an overall score between and 100. Bramblett et al. (2005) did not propose threshold criteria
for good, fair, and poor biological integrity for these scores. Therefore, we applied commonly
used criteria 75 to 100 indicating good to excellent biological integrity, 25 to 74% indicated fair
biological integrity, and <25% indicating poor biological integrity.

Table 1. Fish metrics and classification of fishes captured on the Powder River (2005).


Scientific Name











Hiodon alosoides



River carpsucker

Carpiodes carpio


Shorthead Redhorse




Common carp

Cyprinus carpio


Flathead Chub

Platygobio gracilis


Longnose dace

Rhinichthys cataractae


Plains minnow

Hybognathus placitus


Western silvery

Hybognathus argyritis



Sand shiner

Notropis stramineus


Sturgeon Chub

Macrhybopsis gelida



Plains Killifish

Fundulus kansae



Channel catfish

Ictalurus punctatus



Noturus flavus




































HB = herbivore (> 90% plants or detritus); IC = invertivore/carnivore (>25% both invertebrates and vertebrates); IN = invertivore; OM =

oninivore(25-90% plants or detritus)

t BE = benthic; GE = generahst; WC = water column: Brown (1971); Scott and Crossman (1973); Becker (1983)

X Scott and Crossman (1973); Pflieger (1997); Barbour et al. (1999)

§ Tolerant reproductive strategists are not litho-obligates, use parental care @ spawning site: Scott and Crossman (1973); Pflieger (1997)

** INT = intolerant; MOD = moderately tolerant: TOL = tolerant; Barbour et al. (1999);

tt N = native; I - introduced; Brown (1971); Holton and Johnson (2003)

Derivation of the expected fish communities is performed by identifying the frequency of
occurrence that a species has at a site classified in a reference condition and summing the
frequencies across all fish species of the community (see Appendix B). The O/E (Observed taxa
of an evaluated site/Expected Taxa for a reference site) model is a direct measure of the
biological community. It compares the taxa that are expected at a site (carp and introduced fish
are never "expected" and given zeros) with the actual taxa that were found when the site was
sampled. In some cases, it is more ecologically meaningful than the IBI, but not always.

Macroinvertebrate Collection and Analysis

Paired macroinvertebrate samples taken at each site allowed a comparison of two differing
sampling protocols. The two methods utilized were the EMAP_Targeted Riffle (8 composited
surbers) and the EMAP_Reach-Wide Multi-habitat. These samples were taken in July 2005
following the standard EMAP protocols (Lazorchak 1998), and processed (sorting, identification,
and data analysis) by David Stagliano at the Montana Natural Heritage Program Helena lab.
Macroinvertebrates were identified to the taxonomic level specified by Montana DEQ and
biological metrics were calculated from the data. Montana Department of Environmental
Quality's newest multimetric macroinvertebrate (MMI) protocols (Jessup et al. 2005, DEQ 2006)
were used to analyze the macroinvertebrate samples. Metric results were then scored using the
Montana DEQ bioassessment criteria and each sample categorized as non-impaired or impaired
according to threshold values.

The macroinvertebrate MMI score is based upon a series of metrics that measure attributes of
benthic macroinvertebrate communities regarding condition changes to a stream system (in the
form of pollution or pollutants). The invertebrate metrics include: EPT Taxa Richness (Score =
EPT richness/14*100): Ephemeroptera, Plecoptera &Trichoptera taxa; Percent Tanypodinae
(Score = PercentTanypodinae/10 *100): Tanypodinae is a subfamily within the family
Chironomidae; Percent Orthocladiinae of Chironomidae (Score = (100-percent
Orthocladiinae of Chironomidae/100)*100); Predator Taxa Richness (Score = number of
predator taxa/9*100); Percent Collectors and Filterers (Score = (100 - percent collectors
and filterers/65)*100): This metric measures the relative abundance of collector and filterer taxa
in the sample. The index score represents the condition of the macroinvertebrate community at
the time the sample was collected within that past year. If the index score is below the
impairment threshold, the individual metrics can be used to provide insight as to why the
communities are different from the reference condition (Barbour et. al 1999, Jessup et. al. 2005).
The results from the eastern plains index metrics are averaged to obtain the final index score.
The impairment threshold set by MT DEQ is 37 for the eastern plains stream index (Table 2).

Table 2. Impairment determinations from the MMI and O/E (RIVPACS) models (taken from
Jessup 2005, Feldman 2006).



Low Valley

Eastern Plains


>0.8 or < 1.2
<0.8 or > 1.2

>0.8 or < 1.2
<0.3 or > 1.2

>0.3 or < 1.2
<0.8 or > 1.2




Impairment Determination

Not impaired

Not impaired

Not impaired



Habitat and Water Quality Results and Analysis

Powder River Sites 1 and 5 scored highest in habitat quahty with both the BLM and EPA RBP
assessment protocols, representing 70% & 85% of the best possible score, respectively (Table 3).
Site 5 also had the highest number of recorded channel depths >50cm indicating ample deep
holding areas for fish. Powder River Site 3 scored lowest in both habitat assessment scores
despite having the second highest number of channel depths >50cm, unfortunately many of these
deep areas had unsuitable, unconsolidated substrate (silt, fine sand) to be considered optimum
fish habitat. Temperature increases and dissolved O2 (DO) decreases progressing through the

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Online LibraryDavid M StaglianoAquatic surveys and assessment within the Middle Powder River watershed (Volume 2006) → online text (page 1 of 4)