Review of Flow Duration Methods and Indicators of Flow Duration in the Scientific Literature: Great Plains of the United States


Review of Flow Duration Methods and Indicators

of Flow Duration
in the Scientific Literature:

Great Plains of the United States

March 2022
EPA-840-B-22006

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Review of Flow Duration Methods and Indicators of Flow Duration

in the Scientific Literature:

Great Plains of the United States

March 2022

Prepared by:

Amy James

Ecosystem Planning and Restoration
Cary, NC

Kenneth McCune

Southern California Coastal Water Research Project
Costa Mesa, CA

Raphael Mazor

Southern California Coastal Water Research Project
Costa Mesa, CA

In collaboration with the U.S. Environmental
Method Project Delivery Team:

Ken Fritz

Office of Research and Development
Cincinnati, OH

Tracie Nadeau

Office of Wetlands, Oceans, and Watersheds
Portland, OR

Julie Kelso

Office of Wetlands, Oceans, and Watersheds
ORISE Fellow
Washington, DC

Agency's Streamflow Duration Assessment

Brain Topping

Office of Wetlands, Oceans, and Watersheds
Washington, DC

Rachel Harrington

Office of Wetlands, Oceans, and Watersheds
Washington, DC

The following members of the National Steering Committee, and the Regional Steering Committee for
the Great Plains, provided input and technical review:

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National

Tunis McElwain

U.S. Army Corps of Engineers

Regulatory Branch

Washington, DC

Gabrielle David

U.S. Army Corps of Engineers

Engineer Research and Development Center

Hanover, NH

Matt Wilson

U.S. Army Corps of Engineers
Regulatory Branch
Washington, DC

Rose Kwok

U.S. Environmental Protection Agency
Office of Wetlands, Oceans and Watersheds
Washington, DC

Regional
Kerryann Weaver

U.S. Environmental Protection Agency
Region 5
Chicago, IL

Ed Hammer

U.S. Environmental Protection Agency
Region 5
Chicago, IL

Loribeth Tanner

U.S. Environmental Protection Agency
Region 6
Dallas, TX

Shawn Henderson

U.S. Environmental Protection Agency
Region 7
Lenexa, KS

Suggested Citation: James, A., McCune, K., Mazor, R. 2022. Review of Flow Duration Methods and
Indicators of Flow Duration in the Scientific Literature, Great Plains of the United States. Document No.
EPA-840-B-22006.

This work was funded through EPA contract EP-C-17-001 to Ecosystem Planning and Restoration (EPR).
The views expressed in this report are those of the authors and do not necessarily represent the views
or policies of the U.S. Environmental Protection Agency.

Cover Photos

Jason Daniels

U.S. Environmental Protection Agency
Region 7
Lenexa, KS

Billy Bunch

U.S. Environmental Protection Agency
Region 8
Denver, CO

Rob Hoffman

U.S. Army Corps of Engineers
Oklahoma District
Tulsa, OK

Photos are the property of the U.S. Environmental Protection Agency and were taken as part of data
collection efforts for development of a Streamflow Duration Assessment Method in the Great Plains.

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Table of Contents

Table of Contents	i

Table of Figures	iii

Table of Tables	iii

1.0 STATEMENT OF THE PURPOSE	1

2.1	General approach	2

2.2	Search methods	5

2.3	Analysis of sources	6

2.3.1	Including Sources in the Review	6

2.3.2	Evaluating information about indicators	8

3.0 EXISTING FLOW DURATION ASSESSMENT METHODS	8

3.1	Arid West (Beta)	16

3.2	Western Mountains (Beta)	17

3.3	New Mexico	19

3.4	Temperate US (IN, KY, OH, IL, NH, NY, VT, WV, and WA)	19

3.5	Pacific Northwest	20

3.6	Interim Oregon Method	21

3.7	North Carolina	22

3.8	Eastern Kentucky	22

3.9	Ohio	22

3.10	Idaho	23

3.11	Alberta, Canada (Foothills)	24

3.12	Mediterranean Europe	25

3.13	Czech Republic	27

4.0 INDICATORS IN THE GREAT PLAINS	29

4.1	Geomorphological Indicators	29

4.2	Hydrologic Indicators	30

4.3	Biological Indicators	31

4.3.1	Aquatic macroinvertebrates	31

4.3.2	Algae	37

4.3.3	Bryophytes	38

4.3.4	Riparian and wetland vascular plants	38

4.3.5	Vertebrates	39

i

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6.2 PROPOSED INDICATORS	41

Geomorphological indicators	42

Hydrologic indicators	42

Biological indicators	42

Aquatic macroinvertebrates	42

Algae	42

Bryophytes	43

Wetland and riparian plants	43

Vertebrates	43

6.0 BIBLIOGRAPHY	43

6.1	Flow duration assessment methods	43

6.2	Indicators	48

Biology	48

Geomorphology	54

Hydrology	54

Other Topics	55

ii

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Table of Figures

Figure 1. Map of flow duration regions, showing the northern and southern Great Plains 2

Figure 2. Process for identifying field indicators of flow duration to assess in the AW, WM, and GP 4

Figure 3. Decision tree for reviewing sources 7

Figure 4: Streamflow classifications based on field-measured indicator data in the beta SDAM for the

Arid West (Mazor et al. 2021a) 17

Figure 5: Field-measured and desktop indicator data used in the beta SDAM for the Western Mountains

based on snow-influence (Mazor et al. 2021b) 18

Figure 6. Flowchart used to determine stream flow class in the Pacific Northwest method (adapted from

Nadeau 2015) 21

Figure 7. PHWH stream classification flow chart based on HHEI scoring (from Ohio EPA 2012) 23

Figure 8. Characteristics of seepage-fed and fluvial channels in McCleary et al. (2012) 25

Figure 9. Relationship of aquatic phases to flow duration in Gallart et al. (2017) 26

Figure 7. Relationship between biodrought index scores and flow classes, from Straka et al. (2019) 28

Figure 11. Neohermes aestivation chamber in a dry streambed in Arizona 36

Table of Tables

Table 1. Search parameters and dates used to assemble literature on indicators of flow duration in the

Great Plains 5

Table 2. Methods for assessing stream flow duration and their associated indicators. Asterisks indicate

the protocol covers portions of the Great Plains 9

Table 3. Summary of indicators included in streamflow duration assessment methods from Table 2.

Highlighted columns are those existing SDAMs developed for use in the GP region 12

Table 4. Evaluation criteria for indicators identified in the literature review 14

Table 5. Score interpretation for the New Mexico flow duration method 19

Table 6. Erosion-based Stream Classes and Corresponding Flow Duration Class (adapted from McCleary

et al. 2012) 24

Table 7. Metrics in the Biodrought index developed by Straka et al. (2019) 27

Table 8. GP studies of aquatic macroinvertebrates in different flow duration classes 31

Table 9. Vegetation associated with flow-duration classes 39

Table 10. Great Plains studies offish in different streamflow duration classes 39

Table 11. Characteristic reptiles and amphibian species of different types of stream habitats in the
Midwest (Kingsbury and Gibson 2012) 41

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1.0

STATEMENT OF THE PURPOSE

The purpose of this review is to document methods and indicators that may be used to develop
a streamflow duration assessment method (SDAM) for the Great Plains (GP), with an emphasis
on field-based indicators and methods that distinguish ephemeral, perennial, and intermittent
streams. It describes indicators proposed for testing at both baseline and validation sites across
the GP, following the process of Fritz et al. (2020). Additionally, information on potential study
sites of known hydrology will be included, as gleaned from the existing literature, and from
input from the Regional Steering Committee and other practitioners working in the GP, where
possible.

This work is part of a larger effort by the U.S. Environmental Protection Agency, working
cooperatively with the U.S. Army Corps of Engineers, to develop regional SDAMs for nationwide
coverage (https://www.epa.gov/streamflow-duration-assessment).

Although direct measures of flow duration (e.g., long-term records from stream gauges) are
usually preferred to determine whether a stream is perennial, intermittent, or ephemeral,
indirect indicators of hydrology can also be used for this purpose when direct measures are
unavailable or impractical to deploy (Fritz et al. 2020). Indirect indicators are generally those
which are shaped by the typical hydrology of the channel, such as its geomorphology (e.g.,
presence of bed and bank, channel depositional features, or riffle-pool sequences), associated
biology (e.g., presence and type of macroinvertebrates or presence of wetland plants), and
other hydrology indicators aside from the presence of flowing water (e.g., presence of hydric
soils or sediment on plants and debris). Indirect flow duration indicators have two major
strengths that make them effective tools for those assessing potentially regulated waters and
aquatic resource managers. First, they are substantially less expensive to measure, typically
requiring little more than a single site-visit, whereas stream gauges require substantial
installation and maintenance costs. Second, many indirect indicators reflect long-term
hydrologic characteristics, integrating over space and time; thus, they provide better
information about flow duration than instantaneous or short-term observations of hydrology,
which may be absent during drier periods that may not reflect typical reach conditions (i.e.,
drought conditions).

The GP, within the context of this review, is considered those areas largely dominated by native
prairie-type vegetation (tall-, short-, and mixed grass) that generally receive less than 40 inches
of precipitation a year. However, it is important to note that significant forested areas are also
found in the northeast part of this region as defined, where average yearly rainfall totals are
closer to the upper end of the range (30 to 40 inches). The GP can be divided into a 'northern'
and 'southern' section based on the importance of snowmelt to river discharge, as the
boundary between north and south approximately follows the line south of which mean annual
snowfall is less than 0.7 m (2 ft; Wohl et al. 2016). States within this region include Iowa,

Kansas, Minnesota, Nebraska, North and South Dakota, and Wisconsin, as well as portions of
Colorado, Michigan, Missouri, Montana, New Mexico, Oklahoma, Texas, and Wyoming. (Figure

1).

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Alaska

Pacific
Northwest

Northern
Great Plains

Northeast

Western
Mountains

Southeast

Hawaii

Southern
Great Plains

Figure 1. Map of flow duration regions, showing the northern and southern Great Plains. The
Great Plains, Northeast, and Southeast regions were derived from the 'Ordinary High-Water
Mark (OHWM) Scientific Support Document' (Wohl et al. 2016).

2.1 General approach

To date, flow duration literature reviews have been completed for the Arid West (AW; McCune
and Mazor 2019) and the Western Mountains (WM; McCune and Mazor 2021) regions. For the
GP literature review, existing flow duration assessment methods, data sources, and indicators
identified in these previous literature reviews were reevaluated for their applicability to the GP.
Further queries of literature databases were conducted to identify and evaluate any additional
flow duration methods, data sources, and indicators that should be considered specifically for
the GP.

As with the AW and WM regions, field indicators of flow duration were first identified from
established flow duration methods (Figure 2). Indicators were characterized by type (e.g.,
plants, benthic macroinvertebrates) and endpoint used to assess the indicator (e.g., presence of
indicator taxa, abundance). Indicators identified from existing flow duration methods were
supplemented with additional indicators whose use were supported by scientific literature and
other appropriate sources but were not incorporated into established methods. The full list of
potential indicators was then evaluated for several key criteria:

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Consistency: Does it work? Is there evidence from appropriate sources (see below) that
the indicator can discriminate flow classes across different environmental settings,
seasons, etc.? Indicators were consistent if it was used in at least two methods or
showed support as a discriminatory tool in the scientific literature.

Repeatability: Can different practitioners take similar measurements, with sufficient
training and standardization? Is the indicator robust to sampling conditions (e.g., time of
day)? Repeatability was assessed based on personal knowledge of the field methods.

Defensibility: Does the indicator have a rational or mechanistic relationship with flow
duration in the region being considered? This aspect was assessed based on personal
knowledge of ephemeral and intermittent stream systems in these regions. For
example, hydric soils develop in the anoxic conditions created during prolonged
inundation and therefore are unlikely to be found in ephemeral streams (Cowardin et al.
1979). In contrast, substrate sorting reflects the magnitude of flow (Hassan et al. 2006),
and sorting is evident in ephemeral, as well as perennial and intermittent streams.

Rapidness: Can the indicator be measured during a one-day site-visit (even if
subsequent lab analyses are required)? Methods requiring multi-day visits are outside
the goals of the present study.

Objectivity: Does the indicator rely on objective (often quantitative) measures? Or does
it require extensive subjective interpretation by the practitioner?

For each indicator, it was also noted if there were studies demonstrating its effectiveness in
determining flow-duration classes, if available.

The list of potential indicators meeting most of these criteria resulted in a shortened list of
priority indicators for further evaluation. This list of priority indicators was further evaluated for
two additional desirable (but not essential) criteria:

Robustness: Does human activity complicate interpretation of the indicator in highly
disturbed or managed settings? For example, aquatic vegetation may be purposefully
eliminated from streams managed as flood control channels, limiting the value of
vegetation indicators in certain environments. Although many indicators can be
influenced by human activity, they may still provide value in determining flow class
(particularly in undisturbed streams). Therefore, this was considered an important, but
non-essential, criterion for selecting indicators for exploration.

Practicality: Can the technical team realistically sample and/or observe the indicator in
the present study? For example, if special permits are required for assessment, an
indicator may be inappropriate for further investigation.

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Based ori these criteria, a final list of possible indicators of flow duration were selected to serve
as the basis for field data collection in the GP. The objective here is to identify indicators that
can be combined and evaluated as an SDAM for the GP region. A subsequent objective is to see
how well that preliminary SDAM works compared to an SDAM developed for the Pacific
Northwest (Nadeau 2015) and the method developed by the New Mexico Environment
Department (NMED 2011).

Figure 2. Process for identifying field indicators of flow duration to assess in the AW, WM,

and GP.

4

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2.2 Search methods

First, sources identified in the Arid West and Western Mountain literature reviews were
evaluated for their relevance to the Great Plains. These included flow duration methods from
across the U.S. and elsewhere, data sources that could be more broadly applied across regions,
and sources with data specific to the GP. These sources have already been evaluated using the
decision tree shown in Figure 3 for the AW and WM literature reviews. Therefore, no further
analysis was performed on these sources, unless they had information specific to the GP.

Next, to compile a more thorough collection of GP-specific flow duration sources, additional
searches of reference libraries and using search engines, including Google, Google Scholar and
Web of Science (WOS), were completed. Dates of search, search terms and combinations, and
number of hits for each are shown in Table 1. If the number of hits was large, only the titles or
abstracts of the first 50 search results were reviewed to determine applicability to the subject
and the GP. This compiled library of sources was also supplemented by appropriate sources
from the personal libraries of the technical team.

Table 1. Search parameters and dates used to assemble literature on indicators of flow
duration in the Great Plains

Search

Sear

ch

Key Terms

Hits

Source

Dat

e





WOS

12/2/19

"great plains" AND "flow duration"

19

WOS

12/2/19

"prairie" AND "flow duration"

4

WOS

12/2/19

"great plains" AND ("perennial stream" OR "intermittent

85







stream" OR "ephemeral stream" OR "dry stream" OR "









interrupted stream" OR "seasonal stream" OR "temporary









stream" OR "episodic stream" OR " flow permanence" OR









"intermittency")



WOS

12/2/19

"prairie" AND ("perennial stream" OR "intermittent stream"

43







OR "ephemeral stream" OR "dry stream" OR "interrupted









stream" OR "seasonal stream" OR "temporary stream" OR









"episodic stream" OR " flow permanence" OR









"intermittency")



WOS

12/2/19

("Montana" OR "North Dakota" OR "South Dakota" OR

237







"Minnesota" OR "Wisconsin" OR "Illinois" OR "Iowa" OR









"Kansas" OR "Nebraska" OR "Wyoming" OR "Oklahoma" OR









"Missouri" OR "Texas" OR "New Mexico") AND ("perennial









stream" OR "intermittent stream" OR "ephemeral stream"









OR "dry stream" OR "interrupted stream" OR "seasonal









stream" OR "temporary stream" OR "episodic stream" OR









"flow permanence" OR "intermittency")



WOS

12/5/19

"great plains" AND ("macroinvertebrates" OR "amphibians")

118







AND "stream"



GS

12/4/19

"great plains" AND "flow duration"

325

GS

12/4/19

"great plains" stream indicator AND "flow duration"

496

GS

12/4/19

"great plains" AND "intermittent stream"

1,430

5

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Search

Sear

Key Terms

Hits

Source

Dat

12/4/19

"great plains" AND "perennial stream"

962

12/4/19

"great plains" AND "ephemeral stream"

945

12/4/19

"great plains" AND "flow duration" AND ("macrophytes" OR

428

"algae" OR "bryophytes" OR "riparian vegetation")

12/5/19

"great plains" AND "flow duration" AND

436

("macroinvertebrates" OR "fish" OR "amphibians")

12/6/19

"great plains" AND "hydrologic regime"

1,780

Google

12/30/2019

"Intermittent stream" AND "indicator" AND "Great Plains"

5,340

Google

12/31/2019

"great plains" AND "flow duration"

17,600

Google

12/31/2019

"great plains" AND "streamflow duration" AND "indicator"

293

2.3 Analysis of sources

2.3.1 Including Sources in the Review

Applicability/Utility: Sources with available articles were first reviewed to determine if a source
was 'applicable' for this analysis. Applicable sources were those that provided information
about the biological, physical, or hydrologic characteristics of streams along a flow duration
gradient in the GP. Sources in regions outside the GP were also considered applicable if other
elements of the reference were relevant to the study. Several sources found during searches
did not meet this criterion. Factors that limited the applicability of a citation include reliance on
intensive hydrologic data (e.g., continuous flow gage data), or reliance on other data types that
could not be rapidly measured in the field (e.g., model data, remote sensing inputs).

Once a source was considered applicable, it was evaluated for inclusion in this review following
the decision tree in Figure 3 and as described below.

Review: Sources needed to undergo peer-review, be published by a government agency, or
come from a subject-matter expert. All sources met this criterion.

Soundness: Sources needed to rely on sound scientific principles, and conclusions had to be
consistent with data presented. All sources met this criterion.

Clarity/Completeness: Sources needed to provide underlying data, assumptions, or model
parameters, as well as author sponsorship or author affiliations. Several sources did not provide
a clear basis for determining flow-duration classes for study sites. Where possible, we applied
the most appropriate flow-duration class based on available data, sometimes applying
ambiguous classifications (e.g., "perennial or intermittent", or "intermittent or ephemeral"). If
data were insufficient to support these designations, the source was excluded from the review.

Uncertainty/Variability: Sources needed to identify variability, uncertainties, sources of error, or
bias, reflecting them in any conclusions drawn. This criterion could generally be satisfied
through reported ranges or measures of variability and uncertainty (e.g., standard deviation,

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statistical significance) associated with each indicator and flow-duration class. No sources were
excluded for this criterion.

Figure 3. Decision tree for reviewing sources.

7

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2.3.2 Evaluating information about indicators

Each source was reviewed to identify information about indicators of flow duration. First, the
flow duration classes represented in the study were determined. Classes were either reported
by the authors using their criteria to determine the flow class, or it was determined from other
data presented in the study if not given. For example, sites were classified as perennial if year-
round flow was reported. Where appropriate, ambiguous classes were applied; for example, if a
study reported that a stream dried or had water only in pools, but the duration of the dry
period was unclear, the site was classified as "ephemeral or intermittent." Results, including
manuscript text, figures, and tables, were reviewed for information about indicators associated
with different site classes. Typical levels (e.g., means) and associated measures of variability
(e.g., ranges, standard deviations) were recorded for each indicator.

3.0 EXISTING FLOW DURATION ASSESSMENT METHODS

Thirteen total methods were found to be appropriate for potentially evaluating stream flow
duration classes, as they incorporate indirect indicators of flow duration that can be rapidly
assessed in the field (Table 2), though only two of these are specifically designed for use in
portions of the GP. Table 3 provides a summary of which indicators are used by each method.
An additional six methods were found during the AW and WM literature searches (Kennard et
al. 2010, Trubilowicz et al. 2013, Berkowitz et al. 2011, Noble et al. 2010, Berhanu et al. 2015,
Porras and Scoggins 2013), but were excluded from consideration because they lack a rapid
field component, focusing instead on long-term records of measured or modeled flow.

Table 4 provides a summary of the evaluation criteria (see Section 2.1) applied to indicators.
Indicators that met all criteria were designated as priority indicators. All priority indicators were
proposed for inclusion in the pilot study in the GP. In addition, certain non-priority indicators
used in the New Mexico method are also proposed for use in the GP since this method covers
portions of this region.

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Table 2. Methods for assessing stream flow duration and their associated indicators. Asterisks indicate the protocol covers portions of
the Great Plains.

Source

Geographic
location

Used in Regulatory
Decision-making?

Represented
classes

Biological Indicators

Geomorphological Indicators

Hydrological/Other Indicators

Mazor et al.
(2021a)

Arid West (parts
of AZ, CA, CO,
NM, NV, TX, UT,
and WY)

Currently in beta
testing; intended to
be used by the Corps
and EPA to support
evidence of WOTUS
jurisdiction once final

Perennial,
intermittent, at
least

intermittent, and
ephemeral

Wetland (hydrophytic) plants,
aquatic macroinvertebrates (#
and EPT), algae (presence and %
cover), fish

Supplemental info (for 'needs
more information'):
amphibians/snakes, perennial
indicator macroinvertebrate
taxa, iron-oxidizing
fungi/bacteria





Mazor et al.
(2021b)

Western

Mountains (parts
of AZ, CA, CO,
MT, NM, SD, UT,
and WY)

Currently in beta
testing; intended to
be used by the Corps
and EPA to support
evidence of WOTUS
jurisdiction once final

Perennial,
intermittent, at
least

intermittent, and
ephemeral

Aquatic macroinvertebrates
(abundance and richness,
includes perennial indicator
taxa), algal cover, fish
abundance and presence,
differences in vegetation

Supplemental info (not used in
model): presence of aquatic or
semi-aquatic amphibians and
reptiles, iron-oxidizing
fungi/bacteria

Bankfull width, sinuosity

Long-term precipitation, long-
term maximum air temperature,
snow influence (stratifies what
indicators are used in the model
and how they are interpreted)

Surface Water

Quality

Bureau, NM

Environment

Department

(2011)

New Mexico,
USA*

Yes, as an assessment
methodology for
conducting use
attainability analyses
and to properly
classify streams to
satisfy NM water
quality standards;
does not appear to be
used by Corps Districts
to support WOTUS
jurisdiction

Ephemeral,
perennial and
intermittent

Fish, benthic

macroinvertebrates, filamentous
algae and periphyton, riparian
vegetation, rooted upland plants
in streambed, iron oxidizing
bacteria/fungi, bivalves,
amphibians

Sinuosity, floodplain and
channel dimensions, channel
structure, particle size or stream
substrate sorting

Water in channel, hydric soils,
sediment on plants or debris,
hyporheic zone/groundwater
table, seeps/springs

9

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Source

Geographic
location

Used in Regulatory
Decision-making?

Represented
classes

Biological Indicators

Geomorphological Indicators

Hydrological/Other Indicators

Fritz et al.
(2006)

Temperate USA
(Indiana,
Kentucky, Ohio,
Illinois, New
Hampshire, New
York, Vermont,
West Virginia,
and

Washington)*

No

Ephemeral,
perennial and
intermittent

Benthic macroinvertebrates,
amphibians, algal cover, algal
assemblage, bryophyte
assemblage, riparian canopy
cover

Sinuosity, slope, depth, wetted
width, depth to
bedrock/groundwater table,
streambed sediment
moisture/size distribution

Water chemistry, habitat unit
designation, water velocity,
continuous hydrologic
monitoring

Nadeau
(2015a)

Pacific

Northwest, USA

Yes; used by Corps
Districts and EPA as
supporting evidence
of Waters of the US
(WOTUS) jurisdiction

Ephemeral,
perennial and
intermittent

Benthic macroinvertebrates,
wetland plants, riparian
corridor, fish,
amphibians/snakes

Slope, evidence of
erosion/deposition, floodplain
connectivity



Topping et al.
(2009)

Oregon, USA

No; superseded by the
OR Final SDAM
(Nadeau 2011) and
Pacific Northwest
method (Nadeau
2015). Was primarily
used to test indicators
for development of a
data-driven SDAM

Ephemeral,
perennial and
Intermittent

Wetland plants, fibrous roots
and rooted plants, streamer
mosses or algal mats, iron-
oxidizing bacteria, fungi,
flocculent material, benthic
macroinvertebrates,
amphibians/snakes, fish, lichen
line, riparian vegetation corridor

Continuous bed and bank, in-
channel structure, soil texture or
stream substrate sorting,
erosional features, depositional
features, sinuosity, headcuts
and grade controls

Groundwater/hyporheic
saturation, springs and seeps,
debris piles/wrack lines, evenly
disbursed leaf litter/loose
debris, redoximorphic features
in toe of bank

NC Division of
Water Quality
(2010)

North Carolina,
USA

Yes, to comply with
401 ('waters of the
state') and state-level
rules (riparian
buffers); used by
Corps Wilmington
District as supporting
evidence of WOTUS
jurisdiction

Ephemeral,
perennial, and
intermittent

Fibrous roots in streambed,
rooted upland plants, benthic
macroinvertebrates, aquatic
mollusks, fish, crayfish,
amphibians, algae, wetland
plants in streambed

Presence of

modification/ditches, channel
and bank continuity, sinuosity,
channel structure, streambed
particle size, active/relict
floodplain, depositional
bars/benches, recent alluvial
deposits, headcuts, grade
control (natural), natural valley,
2nd or > order channel,

Baseflow presence, iron
oxidizing bacteria, leaf litter,
organic debris drift
accumulation, sediment on
plants/debris, soil-based
evidence of high- water table

Svec et al.
(2005)

Eastern Kentucky

No

Ephemeral,

intermittent,

perennial



Bankfull width, width to depth
ratio, entrenchment ratio, slope,
watershed area



10

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Source

Geographic
location

Used in Regulatory
Decision-making?

Represented
classes

Biological Indicators

Geomorphological Indicators

Hydrological/Other Indicators

Ohio EPA
(2012)

Ohio

Yes, as an assessment
methodology for
conducting use
attainability analyses
of primary headwater
habitat streams; does
not appear to be used
by Corps Districts to
support WOTUS
jurisdction

Ephemeral,
intermittent/per
ennial (warm
water), perennial
(cold water)

Fish, benthic

macroinvertebrates, amphibians
(salamander community),
riparian zone and floodplain
quality

Average bankfull width,
sinuosity, stream gradient, max
pool depth, number of substrate
types (includes leaf litter) and
percentages of most
predominant types

Water in channel/flow

Savage and
Rabe (1979)

Idaho

No

Ephemeral,
"spring streams"
and permanent

Rooted vascular plants in
channel, bryophytes, aquatic
invertebrates, amphibians, fish

Gradient, substrate

Water in channel

McCleary et al.
(2012)

Alberta, Canada

('Foothills'

region)

No, guides forest
management

Upland, swale,

discontinuous

channel,

seepage-fed

channel, fluvial

channel

In-channel vegetation presence;
plant community type (to
determine soil moisture regime)

Continuous channel, presence of
headcuts, pools, organic
bridges1, bankfull width,
undercut width, particle
size/substrate sorting, riffle-pool
sequence

Water in channel

Gallart et al.
(2017)

Mediterranean
Europe

No

Intermittent-
pools,

intermittent-dry,

episodic-

ephemeral,

perennial;

Hyperrheic,

eurheic,

oligorheic,

arheic,

hyporheic/dry





Hydrologic metrics (based on
modeled or recorded flow),
citizen observations

Straka et al.
(2019)

Czech Republic

No Intermittent,

near-perennial,
and perennial

Benthic macroinvertebrates





1 Created when roots extend across, or large woody debris falls over a channel, thus allowing the forest floor to extend across the channel while the streambed remains
continuous beneath the bridge.

11

-------
Table 3. Summary of indicators included in streamflow duration assessment methods from Table

2. Highlighted columns are those existing SDAMs developed for use in the G

region.

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able 4. Evaluation criteria for indicators identified in the

Indicator

Consistency

Repeatability

Defensibility

Rapidness

Objectivity

Priority
Indicator

Robustness

Practicality

Proposed

Geomorphology

Bankfull width and depth

Continuous bed and banks presence

Undercut width

Depositional or erosional features in the

channel

Depositional or erosional features on the

floodplain

Distinct substrate composition in streambed

from adjacent uplands (particle size or

Yes1

substrate sorting)

Entrenchment ratio (floodplain/channel

Yes1

dimension)

Evidence of active floodplain

Evidence of relict floodplain

Presence of natural grade control

Natural valley presence

Presence of headcuts

In-channel sequences of erosional and

Yes1

depositional features

Stream order

Sinuosity

Yes1

Slope/Gradient

Yes

Organic bridge

Hydrology

Continuous logged data

Groundwater observation

Distribution/amount of leaf litter or debris

Hydric soils or redoximorphic features

Yes

Modeled hydrology

Observed aquatic state

Yes

Reported aquatic state from interviews

Observed or reported soil saturation

Observation of baseflow

Presence of wrack or drift lines

Sediment deposition on plants or debris

Yes

Yes1

Soil-based evidence of a high-water table

Presence of seeps and springs

Yes

iterature review.

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Iron-oxidizing bacteria or fungi

Yes

Velocity

Biology

Algae

Yes

Lichens

Bryophytes

Yes

Fibrous roots in streambed

Wetland vegetation (FACW, OBL, SAV)

Yes

Upland vegetation in channel

Yes

Riparian vegetation

Yes

Aquatic macroinvertebrates - Presence

Yes

Aquatic macroinvertebrates - Abundance

Yes

Aquatic macroinvertebrates - Indicator taxa

Yes

Aquatic macroinvertebrates - Traits

Amphibians - Presence

Yes

Amphibians - Abundance and diversity

Aquatic mollusks -- Presence

Yes

Reptiles - Presence

Yes

Fish - Abundance

Fish - Presence

Yes

Fish - Indicator taxa

Additional indicators from primary literature

Geomorphology

Max pool depth*

Hydrology

Dissolved O2*

Water column organic C+

Woody jams5

Biology

Diatom abundance4

Bird abundance4

Terrestrial arthropods4

Canopy cover4

Riparian vegetation - diversity4

Microbial diversity4

1: Non-priority indicator proposed for inclusion because it is required by the New Mexico protocol (NMED 2011)
* Identified in both AW and WM literature reviews
+ Identified in AW literature review
§ Identified in WM literature review

-------
3.1 Arid West (Beta)

This method is the first produced as part of the cooperative regional SDAM expansion effort
described in Section 1, developed using the process outlined in Fritz et al. (2020). Based on the
statistical analysis of field sampled data, five biological field indicators were found to support
an accurate determination of a stream's flow duration class in the Arid West:

1) How many hydrophytic plant species are growing in the channel, or within one half-
channel width of the channel?

2) How many aquatic macroinvertebrate individuals are found?

3) Is there evidence of aquatic stages of EPT taxa?

4) Are algae found on the streambed?

5) Are single indicators (i.e., the presence of fish or >10% algal cover) of intermittent or
perennial streamflow duration observed?

The first four indicators are evaluated together to assign a preliminary flow duration class; the
presence of single indicators, #5 above, determines that a reach is "at least intermittent", even
if the assigned preliminary flow class determined from indicators 1-4 was ephemeral. Field-
measured indicator data is applied to the decision matrix shown in Figure 4, sequentially from
left to right, to determine flow class (Mazor et al. 2021a).

-------
I. Hydropkvtic

1. Aquatic

3. EPT

-t. Algae

5. Single indicators

Classification

plant species

invertebrates

taxa

• fish present

• algae cover > 10%

Absent

Ephemeral

None

Absent

Present

At least intermittent

Present

Absent

Need more information

Present

At least intermittent

Absent

Need more information

Absent

Present

At least intermittent

Few (1-19)

Present

Absent

Need more information

Present

At least intermittent

None

Present

At least intermittent

Absent

Need more information

Absent

Present

At least intermittent

Many (20+)

Present

Absent

Need more information

Present

At least intermittent

Present

At least intermittent

Absent

Need more information

None

Absent

Present

At least intermittent

Present

At least intermittent

Absent

Intermittent

Few (1-19)

Present

At least intermittent

Few (1-2)

Present

At least intermittent

Absent

Intermittent

Many (20+)

Present

At least intermittent

Present

Absent

At least intermittent

Present

Intermittent

Absent

Need more information

None

Absent

Present

At least intermittent

Present

At least intermittent

Absent

At least intermittent

Few (1-19)

Many (3+)

Present

Perennial

Absent

At least intermittent

Many (20+)

Present

Perennial

Figure 4: Streamflow classifications based on field-measured indicator data in the beta SDAM for

the Arid West (Mazor et al. 2021a)

3.2 Western Mountains (Beta)

This method is the second produced as part of the cooperative regional SDAM expansion effort
described in Section 1, developed using the process outlined in Fritz et al. (2020). Based on the
statistical analysis s of field sampled data, six field indicators (4 biological and 2
geomorphological) and two climactic indicators available through online geodatabases were

-------
found to support a determination of a stream's flow duration in the Western Mountains (Mazor
etal. 2021b):

Field Indicators

1) The abundance and richness of aquatic invertebrates (specifically, the total
abundance, the abundance of mayflies, and the abundance and richness of
perennial indicator families)

2) Algal cover on the streambed (%)

3) Fish abundance (0-3 score, where 0 is no fish or only mosquitofish observed)

4) Differences in vegetation between the channel and surrounding uplands (0-3 score,
where 0 is no difference)

5) Bankfull channel width

6) Sinuosity (0-3 score, where 0 is poor)

Climactic Indicators (supported through a web application designed for this effort)

7. Long-term precipitation (average precipitation in May and October)

8. Long-term maximum annual air temperature

The presence offish may also be used as a single indicator to classify a stream as "at least
intermittent" even if other indicators suggest an ephemeral classification. This method is
stratified by snow-influence, as shown in Figure 5.

Snow-influenced areas

Non-snow influenced areas

Aquatic invertebrates:

• Total abundance

• Abundance of mayflies

• Abundance of perennial indicatorfamilies

• Number of perennial indicatorfamilies

• Number of perennial indicator families

Algal cover on the streambed

Fish presence (as a single indicator)

Fish abundance (as a core indicator) and Fish
presence (as a single indicator)

Differences in vegetation

Bankfull channel width

Sinuosity

Climate

• October precipitation

• May precipitation

• Annual maximum temperature

Figure 5: Field-measured and desktop indicator data used in the beta SDAM for the Western
Mountains based on snow-influence (Mazor et al. 2021b).

The beta SDAM for the Western Mountains relies on a random forest model to make stream
flow duration classifications (ephemeral, intermittent, at least intermittent, and perennial) and
a web application is publicly available to complete the assessment. Supplemental indicators
that provide further evidence for a streamflow classification are also noted in the field (but are

-------
not used as input into the random forest model): presence of aquatic or semi-aquatic life stages
of reptiles and amphibians, and the presence of iron-oxidizing fungi and bacteria.

3.3 New Mexico

The New Mexico Environment Department developed a two-level method for assessing flow
duration (NM Environment Department 2011) for streams throughout the state, including the
small portion that lies within the Great Plains region as defined in this analysis. The first level
(Level 1) is more rapid and is sometimes sufficient to classify a stream as perennial,
intermittent, or ephemeral. Level 1 relies on qualitative sampling of benthic
macroinvertebrates, fish, filamentous algae, and other organisms, plus field observation of
channel morphology and soils. In some cases, a second level (Level 2) consisting of quantitative
fish and benthic macroinvertebrate samples may be necessary. Level 2 also requires the use of
continuous loggers or stream gages to measure water presence. In this method, 14 indicators of
flow duration ("attributes") are scored, yielding a index that forms the basis of the classification
(Table 5). Notably, this method may result in ambiguous situations (gray rows in Table 5), which
may be resolved by the more intensive Level 2 analysis, and by investigation of adjacent
reaches. Certain indicators (specifically, fish and aquatic macroinvertebrates) may result in a
perennial designation, even if scores are low. Like Nadeau (2015), this method was also
designed for application in semi-arid regions. Like Topping et al. (2009), many indicators require
subjective visual assessment by practitioners.

Table 5. Score interpretation for the New Mexico flow duration method.

Waterbody
type

Level 1 total score

Determination

Ephemeral

Less than 9.0

Stream is ephemeral

> 9.0 and < 12.0

Stream is recognized as intermittent until further analysis
(Level 2) indicates that the stream is ephemeral.

Intermittent

> 12 and < 19.0
or score is lower but aquatic
macroinvertebrates and/or
fish are present

Stream is intermittent

> 19.0 and < 22.0

Stream is recognized as perennial until further analysis
(Level 2) indicates that the stream is intermittent

Perennial

Greater than 22.0

Stream is perennial

3.4 Temperate US (IN, KY, OH, IL, NH, NY, VT, WV, and WA)

Fritz et al. (2006) described a comprehensive suite of protocols for measuring potential flow
permanence indicators in headwater streams, which, due to their position in the landscape, are
more prone to drying. The suite of indicators and description of collection methods described is
more comprehensive than the other listed SDAMs, but no conclusive flow duration
classification is drawn upon at the end of the analysis. Indicators are physical or biological and
include channel slope, basic channel geomorphology (bankfull width and depth, entrenchment
ratio), water depth (maximum pool depth, thalweg depth), macroinvertebrates, and algae,

-------
among others. Publications following this report (Fritz et al. 2008; Johnson et al. 2009; Fritz et
al. 2009; Roy et al. 2009) assess the effectiveness of someeach indicators separately. These
methods have been applied widely throughout the USA, mostly outside the GP (except for IL).

3.5 Pacific Northwest

For purposes of classifying perennial, intermittent and ephemeral streams in the Pacific
Northwest (PNW), Nadeau (2015) developed a method that uses five biological and physical
habitat indicators: 1) presence of aquatic macroinvertebrates; 2) number of mayflies (order
Ephemeroptera); 3) presence of perennial indicator taxa from Mazzacano and Black (2008) or
Blackburn (2012); 4) presence of wetland indicator plants (specifically, SAV, FACW, orOBL) as
determined from regionally appropriate wetland plant lists; and 5) reach slope. Single indicators
such as the presence of fish and aquatic stages of amphibians may result in an "at least
intermittent" classification. Ancillary indicators, such as evidence of sediment erosion or
deposition, are also considered as contextual support for the flow duration determination.
Indicators are measured objectively, without requiring subjective or qualitative visual
assessments by practitioners. This data-driven method resulted from a three-state study (Idaho,
Oregon, and Washington; Nadeau et al. 2015) of the Oregon Interim Method (Topping et al.
2009; see 3.2).

Indicators are evaluated with a simple branching flow-chart (Figure 6), and not all indicators are
needed to make a determination at every site. Consequently, it is among the simplest tools to
implement. This method strongly emphasizes biological indicators, including only one
geomorphological indicator (i.e., slope), and no hydrological indicators.

-------
Figure 6. Flowchart used to determine stream flow class in the Pacific Northwest method

(adapted from Nadeau 2015).

3.6 Interim Oregon Method

Prior to the development of the method of Nadeau (2015) for the PN W, Topping et al. (2009)
developed a flow duration assessment tool for Oregon that evaluates a series of
geomorphological, hydrological, and biological indicators as absent, weak, moderate, or strong
along a stream reach. In general, the strength of the indicator is considered evidence of longer
flow durations. Each indicator is scored and summed; if the total score is below 13, the stream
is considered ephemeral, and if the total score is above 25, the stream is considered perennial.
Single indicators (e.g., presence offish, amphibians, or aquatic macroinvertebrates) may result
in a classification of "at least intermittent.". In contrast to Nadeau (2011, 2015), assessing the
strength of the indicators requires subjective visual assessments by users.

Note that the release of the data-driven Final Streamflow Duration Assessment Method for
Oregon (Nadeau 2011) superseded the use of the Interim Method in Oregon; the Final Oregon
Method was, in turn, superseded by the substantively similar Streamflow Duration Assessment

-------
Method for the Pacific Northwest (Nadeau 2015) as a result of a three-state validation study
(Nadeau et al. 2015).

3.7 North Carolina

This method, developed by the North Carolina Division of Water Quality (2010), includes 9
biological, 11 geomorphic, and 6 hydrologic indicators to determine if a stream is perennial,
intermittent, or ephemeral, as well as to designate locations in the landscape as origins of
streamflow, or sinks where flow ceases. As with the New Mexico method, indicators are scored
to yield an index, with more indicators (or more robustly evident indicators) yielding a higher
score; similarly, the presence of specific taxa (fish, crayfish, amphibians, or clams) can result in a
perennial designation, even if scores are low. Scores required for perennial or intermittent
designations are somewhat higher for the North Carolina method than the New Mexico
method, perhaps due to the higher number of indicators (26 vs. 14). This method was
developed for a region that generally receives at least 5-10 more inches of annual rainfall
(excluding far southwestern NC, where rainfall totals are much higher) than the wettest parts of
the GP and about 4 times more annual rainfall than the driest parts of the GP.

3.8 Eastern Kentucky

This method by Svec et al. (2005) was developed to determine the flow duration of a stream
(ephemeral, intermittent, or perennial) in the context of determining required silivicultural best
management practices in the eastern coalfield region of Kentucky. The authors measured a
suite of channel geometry characteristics to determine their power to predict flow duration,
including bankfull width, mean bankfull depth, width to depth ratio, flood prone width,
streambed slope, depth to bedrock, entrenchment ratio, and cross-sectional area. The most
predictive measurements of flow duration were found to be watershed area, stream slope,
bankfull width, width to depth ratio, and entrenchment ratio. However, it is important to note
that none of the streams sampled in this study were truly ephemeral (defined in this study as
having measureable discharge <10% of the time), with no streams having <50% flow duration.
Therefore, predictive models developed from data collection in this study may not apply as
robustly to ephemeral or near-ephemeral intermittent streams as they do to perennial streams
or near-perennial intermittent streams.

3.9 Ohio

Ohio EPA (2012) has developed an assessment and classification method for Primary
Headwater Habitat (PHWH; generally, drainage areas less than 1.0 mi2 and deep pools are less
than 40cm) to better evaluate water quality in small headwater stream ecosystems. This
method determines different stream classes (Class I, II, and III) based on the type of biological
community the stream can support. These classes are partially based on flow duration, where
Class I streams are considered ephemeral, Class II streams are considered intermittent to
perennial (warmwater), and Class III streams are considered perennial streams influenced by
groundwater (coldwater). There are three levels of assessment, where the first two levels are

-------
considered 'rapid': Level 1 is a physical assessment of habitat using the headwater habitat
evaluation index (HHEI), Level 2 incorporates qualitative biological sampling, and Level 3 is a
quantitative biological assessment of vertebrate and macroinvertebrate communities (taxa
evaluated to lowest practicable taxonomic level). Level I metrics include substrate (including
habitat such as leaf packs and fine detritus), maximum pool depth, and average bankfull width.
Scores from these metrics determine the HHEI, which is then fed into the flowchart in Figure 7.
Generally, Level I, combined with Level II, is enough to determine the PHWH stream class;
however, the use of Level III is the final arbiter of stream class.

Figure 7. PHWH stream classification flow chart based on HHEI scoring (from Ohio EPA 2012)
3,10 Idaho

Savage and Rabe (1979) classified lower order (l°-4°) streams in Idaho (and applicable to other
Rocky Mountain states) based on physical, chemical, and biological differences. The five stream
classes include ephemeral, spring-fed, and three types of permanent streams (just categorized

-------
as '1', '2', and '3'). Ephemeral streams are described as only containing water during high
runoff, though this characteristic appears to be the only one used to distinguish it from the
other classes. Spring-fed streams have a major spring source, with little seasonal variation in
discharge (likely perennial). The different types of permanent streams are largely distinguished
by gradient (expressed as bedform pattern, e.g. riffle-pool vs. meandering-glide) and type of
substrate. 'Permanent' streams, as described by the authors, have high seasonal variation in
flow volume and intermittency, especially in the summer months, which appears to indicate
that truly 'intermittent' streams are likely included in this category with non-spring-fed
perennial streams. The biological community of the three types of permanent streams is also
characterized, including vascular plants, algae, liverworts, benthic macroinvertebrates,
amphibians, and fish. However, because intermittent streams are not separated from perennial
streams in the permanent stream class, this system has low utility as a flow duration
assessment method.

3.11 Alberta, Canada (Foothills)

This method was developed for use in the forested Foothills region of Alberta to assign erosion-
based stream classifications to headwater streams to better inform forest management
decisions (McCleary et al. 2012). These classifications are largely based on dominant surface
erosion processes, which are often driven by degree of flow permanence. The classes align with
traditional flow duration categories as shown in Table 6.

Table 6. Erosion-based Stream Classes and Corresponding Flow Duration Class (adapted from
McCleary et al. 2012)

Class

Best corresponding flow
duration class

Class Description

Upland

Upland (none)

Surface erosion driven by overland flow and
tree root throw; no depression or surface water
present; usually vegetated, with non-
hydrophytic species.

Swale

Ephemeral

Historic channel migration removed material
and created a depression. Feature is vegetated,
with hydrophytic species.

Discontinuous channel

Intermittent

Includes alternating sections of channel and
vegetated ground. Channel may be actively
migrating upstream or in recovery with
encroaching vegetation, but vegetation will
usually be limited or absent in the channel
itself.

Seepage-fed channel

Intermittent, transitional,
or small permanent

Channel with a continuous bed but insufficient
stream power to transport larger streambed
material; therefore, these channels generally
lack typical bed features (e.g. regular riffle-pool
sequence).

-------
Fluvial channel

Small or large permanent

Channel with a continuous bed and sufficient
amount of power to transport most material
endemic to the area.

Simple observations (type, presence/absence of vegetation, continuity of channel) are used to
distinguish the first 2 stream classes (not including upland) from each other and seepage-fed
and fluvial channels. For seepage and fluvial channels, the indicators shown in Figure 8 are used
to determine the class. This method is a simple way to distinguish epehemeral and
discontinuous intermittent streams; however, for continuous channels, it is not able to
distinguish intermittent from perennial streams.

feature
number

Seepage-fed
channel features

Fluvial
channel features

Fine bed material collected from deepest
part of channel is mostly silt and organic
matter. If required, use a hand texturing
procedure to confirm3.

Fine bed material collected from deepest
part of channel is mostly well-sorted sand.
If required, use a hand texturing
procedure to confirm3.

Unconsolidated bed along the deepest
part of channel. Indicated if when
standing on one foot, the surveyor's boot
sinks to a depth > 10 cm.

Consolidated channel bed. Indicated if
the surveyor's boot does not sink to a
depth of > 10 cm.

No steps / riffles created by mobile gravel
or cobblesb.

Steps/ riffles with regular spacing created
by mobile gravel or cobbles'3.

No pools present13.

Pools present with regular spacing6.

Organic bridges present13.

No organic bridges present13.

Head cuts present6 andc.

No head cuts present13 andc.

Maximum bankfull widthd >3x the
minimum width.

Maximum bankfull widthd <3x the
minimum width.

Total undercut width6 > bankfull width.

Total undercut width6 < bankfull width.

Total

See Section 3.1 for interpreting tally

Figure 8. Characteristics of seepage-fed and fluvial channels in McCleary et al. (2012)

3,12 Mediterranean Europe

Prat et al. (2014) developed an assessment framework known as Mediterranean Intermittent
River ManAGEment (MIRAGE) to identify the flow status of streams in order to guide selection
of appropriate condition assessment tools based on biology, water chemistry, habitat, or other
condition indicators. The first step in analysis is determining the flow duration of a stream using
the Temporary Stream Regime Tool (TRS-Tool; Gallart et al. 2012, Ga I lart et al. 2017). The TRS-

-------
Tool uses three potential sources of flow estimation/observation to determine stream flow
classification: 1) interviews, 2) interpretation of high-resolution aerial photographs and rapid
field observation, and 3) outputs from hydrologic rainfall-runoff models. Flow classification is
largely focused on different types of temporary streams.

Interview methodology is documented in Gallart et al. (2016). Interviews target locals
encountered in the vicinity of a stream in question, who either live or tend land along the
stream. The core interview consists of five key questions:

1. How often does flow cease?

2. During non-flowing months, are there pools and for how long?

3. When there is no surface water, is there water in the alluvium?

4. How frequently are flow/pools/dry riverbeds observed during each season?

5. Have any changes in flow regime been observed recently?

Rapid field observations and photographic interpretation focuses strictly on hydrologic
indicators, such as presence of pools, riffles, or dry streambed over several visits. Interviews
and observations allow for a finer categorization of different aquatic states that involve flow as
well as disconnected pools and dry riverbed. These are represented by flow permanence (Mf),
pool permanence (Mp), and dry-period permanence (Md) in Figure 9. Using this plot, further
flow regime classifications (e.g., fluent-stagnant, quasi-perennial, episodic) are then defined.

Always flow

Arrangementof the three main metrics that correspond to the three aquatic phases:
flow permanence (Mf). Isolated pools permanence (Mp) and dry river permanence (Md).
in the FPD (Flow - Pools - Dry) graph.The arrowsshow the progression of every one of the
three metrics whereas the axes show the values of every one of them. The central point
represents a river that undergoes the three aquatic phases with the same frequency.

Figure 9. Relationship of aquatic phases to flow duration in Gallart et al, (2017).

-------
3.13 Czech Republic

Straka et al. (2019) recently developed a "biodrought" index to classify streams as perennial or
intermittent based strictly on the composition of benthic macroinvertebrate communities
(Figure 7). Based on a data set of 23 streams in the Czech Republic (mostly in the Carpathian
Mountains and Central Highlands) consisting mostly of paired perennial and non-perennial sites
(both "intermittent" and "near perennial"), they identified indicator species associated with
different flow regimes, and developed a seasonally-adjusted index consisting of three metrics
that could discriminate between the three flow-regime classes (Table 7).

Table 7. Metrics in the Biodrought index developed by Straka et al. (2019)

Metric

Flow state indicated by
high values

Proportion of indicator taxa (perennial indicators/ perennial +
intermittent indicators)

Perennial

Proportion of taxa with high body flexibility

Intermittent

Preference for organic sustarte (Autumn samples only)

Intermittent

Total abundance (Spring samples only)

Perennial

-------
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BIODROUGHT index

Figure 10. Relationship between biodrought index scores and flow classes, from Straka et al.
(2019). Top panel shows the probability of classification as the index score increases. The
second panel shows scores associated with calibration data. The bottom panel shows scores
associated with independent validation data. INT: Intermittent. NPE: Near-perennial. PER:
Perennial.

As with Nadeau (2015), the index of Straka et al. (2019) uses aquatic invertebrates to
discriminate between perennial and intermittent streams, but not to discriminate ephemeral
streams. But the two indices differ in a few important aspects. First, indicator taxa were
identified at the species or genus level, which reduces the rapidness of this method if lab-based
identifications are required. Second, indicator taxa were identified through an empirical
method (i.e., indicator species analysis), whereas the indicators of Nadeau (2015) were derived
from life history information and experience of stream ecologists in the Pacific Northwest
(Blackburn and Mazzacano 2012). Third, the biodrought index takes into account the presence
of intermittent indicator taxa, whereas the method of Nadeau (2015) found superior
performance when only perennial indicator taxa are considered. This index has not been
validated in the field.

-------
4.0

INDICATORS IN THE GREAT PLAINS

A review of literature describing indicators in the GP shows general support for indicators used
in current flow duration assessment methods, particularly biological indicators. A discussion of
each class of indicators and evidence for their association with streamflow classes in the GP is
given below.

4.1 Geomorphological Indicators

Aside from New Mexico Level I indicators that assess geomorphology, there were no studies or
other methods found that defined differences in stream geomorphology based on flow
duration classification in the GP. Instead, relevant studies described the characteristics of GP
streams with known flow duration and/or substrate types. Costigan et al. (2014) found that for
a large, perennial sand-bed stream in south-central Kansas (Ninnescah River), bed slope and
sinuosity decreased, and bankfull width to depth ratios increased, as the channel progressed
downstream. Friedman and Lee (2002) found that ephemeral sand-bed channels in the
Colorado piedmont widen and narrow in response to flooding and periods of low-flow
respectively. Channel narrowing was also accompanied by an increase in forest width of a
similar magnitude, as trees (primarily cottonwoods) became established in the channel bed
during these periods of low flow. In a preliminary analysis of potential controls on refuge pools
(those that retain water throughout the year, but are often isolated for long periods), Wohl et
al. (2009) describe typical ephemeral and intermittent channels found on the Pawnee National
Grassland (northeast CO) as grassy swales with relatively broad, shallow active channels, highly
variable degrees of longitudinal incision, and active headcuts throughout.

Tufa Deposits

In alkaline waters rich in carbonate, tufa deposits may form under certain conditions. Tufa
deposition processes are highly dependent on physiochemical and biological factors not directly
related to flow duration (Ford and Pedley 1996). For example, Ford and Pedley (1996)
described areas throughout the US (including sites in the GP) in which tufa formations occur,
including fossil tufa sites, where historical conditions allowed for the formation of tufa but are
no longer actively forming - meaning that tufa presence is not representative of the current
present-day hydrologic condtions. No studies were found to support the use of tufa deposits as
an indicator of flow duration, as the basis of their formation is not explicitly linked to flow
duration and the presence of such formations is not an indicator of present-day stream flow.
Observations of tufa formations in an ephemeral stream by Wright (2000) showed that minimal
flow is needed for such formations, whereas flow obstructions can be the major factor affecting
tufa formation in ephemeral streams. Other than Wright (2000), there were no other studies
found that focused on describing connections between flow duration and tufa formation;
rather, most research found aimed at understanding the physiochemical or biological processes
that affect tufa formations.

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4.2 Hydrologic Indicators

Several methods identified in this review use the prevalence and/or distribution of leaf
litter/packs or wrack lines (e.g., Topping et al. 2009, NCDWQ 2010) to distinguish between flow
duration types. For leaf litter, the interim Oregon and North Carolina methods assign scores for
this indicator based on the assumption that more leaf litter will be retained in ephemeral and
intermittent channels due to prolonged absences of flow that might move leaf debris out of a
reach. The North Carolina method was developed for a largely forested ecoregion while the
interim Oregon method was developed for a region that encompasses both forests and arid
grasslands.

In grassland dominated areas of the GP, allochthonous organic matter inputs are expected to
be lower than in forested systems, especially in ephemeral headwater reaches that may lack a
riparian gallery forest. In addition, prairie streams tend to retain less of this material because of
frequent scouring floods and a lack of retentive structures such as large wood (Gurtz et al.
1988). However, two studies identified in this review compared the decomposition rates of leaf
packs in intermittent and perennial streams within the GP: in north-central Texas (Hill et al.
1988) and northeastern Kansas (Tate and Gurtz 1986). Both studies found that decomposition
rates of hardwood leaf litter (e.g., elm, box elder, pecan) were slower in intermittent channels
versus perennial channels; therefore, leaf litter might be expected to persist longer in those
environments, due not just to absence of flow but potential differences in decay rates.

Dry conditions hinder both microbial growth and macroinvertebrate re-colonization times,
which likely impact decomposition processes. However, Tate and Gurtz (1986) found a low
prevalence of macroinvertebrate shredders, which are considered an important factor in
detritus processing, in both intermittent and perennial channels. This outcome suggests that
their absence did not play a crucial role in decay rate differences, at least in this study. It is
important to note that the use of this indicator in grassland dominated areas of the GP may be
confounded by a lack of woody vegetation (at least for headwaters higher in the drainage
network) and the characteristic high intensity flooding events typical of this region.

Woody jams

In the Western Mountains (WM) literature review, large woody jams (also called "debris jams")
are identified as a potentially important component of streams in the WM (e.g. Mersel and
Lichvar 2014; Faustini and Jones 2003, Abbe and Montgomery 1996). In addition, most of the
studies in Mersel and Lichvar (2014) investigating the impacts of large woody jams on stream
ecology, stream channel morphology, water velocity, and to a lesser extent, flow duration, are
from more heavily forested regions largely in the Pacific Northwest. No studies on the
importance of woody jams (for flow duration or otherwise) in the GP were found during the
literature review.

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4.3 Biological Indicators

In contrast to many of the other indicators mentioned above, biological indicators are often
directly related to flow duration. Consequently, many studies corroborated relationships
between biological indicators and flow duration, particularly aquatic macroinvertebrates and
plants. Also included here are discussions of studies from the Arid West (AW) and Western
Mountains (WM) since biological indicators can be widespread; if a study is specific to the Great
Plains (GP), it is indicated as such.

4.3.1 Aquatic macroinvertebrates

In general, studies provide strong support for the use of aquatic invertebrates as indicators of
flow duration. Although training is required, field-based family level identifications are practical
for aquatic macroinvertebrates, further underscoring their suitability as indicators. The Pacific
Northwest method (Nadeau 2015) makes use of studies by the Xerces society (i.e., Mazzacano
and Black 2008, Blackburn and Mazzacano 2012) to identify perennial indicator taxa in the
Pacfic Northwest and many of these taxa, where present, may have similar indicator values in
the GP (see below).

In addition, studies conducted in the GP that compared or characterized community
composition and/or abundance of macroinvertebrates in perennial streams and streams with
shorter flow durations were found during this literature review and are summarized in Table 8.
Study results are presented at different taxonomic resolutions, ranging from genus and species
to family level or higher. Provided flow classifications are also of varying levels of specificity,
with streams having shorter than perennial flow duration often not categorized into
intermittent or ephemeral classes.

Table 8. GP studies of aquatic macroinvertebrates in different flow duration classes.

Source

Region

Notes

Perennial

Intermittent/
Ephemeral

Bovbjerg et
al. (1970)

Upper Little
Sioux River in
Minnesota
and Iowa

Sampled aquatic fauna
in intermittent and
perennial sections of
the river

Associated taxa: All unionid
mussels and Sphaerium sp.,
Ferrissia, Callibaetus, Caenis,
Isonychia, Ameletus,
Ancyronyx, Ischnura, and
Orconectes virilis

Associated taxa: Stagnicola
reflexa, Planorbula,
Peltodytes, Pelonomus, and
Notonecta

Bramblett
and Fausch
(1991)

Southeastern
Colorado -
Purgatoire
River and 10
tributaries

Habitat and biota
descriptions;
tributaries not given a
definitive flow
classification

Associated taxa (Purgatoire
River): Choroterpes
mexicanus, Microcylloepus,
Cheumatopsyche,
Hydropsyche, Simuliidae;
mostly collector-gatherers
and filterers

The tributaries had a greater
preponderance of predators
(odonates) and scrapers
(physid snails)

-------
Source

Region

Notes

Perennial

Intermittent/
Ephemeral

Buchholtz
and

Buchholtz
(1974)

Southeast
South Dakota
(Vermilion
River)

Sampled aquatic fauna
in intermittent and
perennial ('continous')
sections of the river

Associated taxa: Ischnura,
Leucorrhinia, Trichocorixa,
Agabus, Enallagma, Ranatra,
and Laccophilinae

Associated taxa: Ferrissia,
Suphisellus

Burkand
Kennedy
(2013)

North-central
Texas(Ash
Creek [spring
fed] and
tributaries)

Evaluated perennial
riffles and pools, and
disconnected pools
(shaded and non-
shaded); except for
Ash Creek, no
definitive flow
classification is given

Associated taxa (perennial
riffles): Chimarra,
Cheumatopsyche, Similium,
Lutrochus, Neotrichia, and
Mayatrichia

Found in shaded disconnected
pools lacking surface flow for
over a month: Marilia,

Oecetis, Helicopsyche, and
Microcylloepus

Fritz and
Dodds(2002)

Northeast
Kansas (Kings
Creek/Konza
Prairie

Evaluated role of
disturbance (e.g.
drying, flood) and
refugia on benthic
assemblage in
intermittent and
perennial streams

Associated taxa:
Hydropsyche,

Neochoroterpes, Calopteryx
maculata, and Argia plana

Associated taxa: Brachyceran
Diptera (Phoridae, Sepsidae,
Scathophagidae)

Harrell and
Dorris (1968)

North-central
Oklahoma
(Otter Creek
drainage)

Characterized benthic
macroinvertebrate
community of
intermittent streams

Not Applicable (N/A)

Oligochaetes (70%) and
dipterans (22%) made up
majority of all macrobenthos
collected in pools; dipterans
(Pelopia spp.) replaced
Limnodriulus spp. as the
dominant taxon as water
levels receded in summer

Harris et al.
(1999)

Nebraska and

southwest

Minnesota

Characterized benthic
macroinvertebrate
community in
perennial streams

Associated taxa (most
abundant): Chironomidae,
Simuliidae, Oligochaeta,
Nemotoda, Heptagenia,
Leptophlebia, Taniopteryx,
Baetidae, Physidae

N/A

King et al.
(2015)

Austin, Texas

(urban

streams)

Uses Flow
Permanence Index
(FPI; Porras and
Scoggins 2013); ranges
from 0 to 100. No
estimated score
ranges are given for
perennial,
intermittent, and
ephemeral flow

Taxa found only in streams
with an FPI of 90 or above:
Heterelmis, and
Nectopsyche; others
appearing and increasing
substantially in number
above an FPI of 70 include
Psephenus, Isonychia,
Macrelmis texanus, and
Erpetogomphus

Physella snails experienced
large increases in streams
with an FPI of 30 or lower

-------
Source

Region

Notes

Perennial

Intermittent/
Ephemeral

Miller and

Golladay

(1996)

Southern
Oklahoma

Macrobenthos
response to flooding
events ('spates) in a
perennial and
intermittent stream

Associated taxa: Baetis,
Chimarra, Leptophlebia,
Tricorythodes, and Tipulidae;
Chironomids were most
common invert found in both
stream types.

Intermittent associated taxa:
Physella, Zealeuctra, Perlesta,
and Perlodidae; large
numbers of Caenis and
Simuliidae, though these taxa
were found in both stream
types; chironomids were most
common invert found in both
stream types.

Stagliano
(2005)

Missouri
River

drainage in
Montana

Aquatic community
classification-
includes perennial and
intermittent streams
in the northern
glaciated Plains and
northwestern Plains
ecoregions

Many species are common
between smaller perennial
and intermittent streams
(including mayflies Caenis
and Callibaetis); however,
Cheumatopsyche,
Hydropsyche, Dubiraphia,
and Microcylloepus were
found only in the perennial
streams

Intermittent streams with
fishless pools that re-hydrate
may be dominated by
crustaceans with resting egg
stages: Ostracoda, Copepoda,
Cladocera, Branchinecta (fairy
shrimp), Caenestheriella (clam
shrimp), and Lepidurus
(tadpole shrimp)

Vander
Vorste et al.
(2008)

Eastern

Montana

(northern

glaciated

Plains)

Characterized benthic
macroinvertebrate
community of
intermittent streams
(family level)

N/A

Chironomidae was most
prevalent taxa in sampled
intermittent streams; in
general, collector-gatherers
and burrowers were the most
common taxa found

Vander South Dakota Characterized benthic N/A
Vorste (2010) (northern macroinvertebrate
glaciated community of
Plains) intermittent streams
(family level)

Families found in highest
abundance were
Chironomidae, Tubificidae,
Enchytraeidae,
Ceratopogonidae, Culicidae,
and Lymnaeidae

Below, major groups of aquatic macroinvertebrates are considered in relation to flow duration;
studies are not confined to the GP, but also draw from the AW and WM literature reviews,
where applicable.

Mollusks

In the AW and WM literature reviews, there was generally strong support for the perennial
indicator status of mollusks (e.g., Lusardi et al. 2016), particularly for the New Zealand mudsnail
(Potamopyrgus antipodarum), a non-native invader in streams throughout the West (e.g.,
Herbst et al. 2008, Bogan et al. 2013) that has extended its range into parts of the GP. However,
Straka et al. (2019) identified this taxon as an indicator of intermittent or nearly perennial
Czech streams, along with numerous taxa in Physidae, Planorbiidae, and Lymnaeidae. A number
of Lymnaeid taxa were also indicators of perennial flow, along with the Ancylid snail Ancylus
fluviatilis. However, in the GP, Bovbjerg et al. (1970) found members of Planorbiidae and
Lymnaeidae in intermittent reaches of the Little Sioux River. Three studies conducted in the GP

-------
also found that Physid snails (mostly Physella) were found or were in greater abundance in
streams with less than perennial flow (Bramblett and Fausch 1991, King et al. 2015, and Miller
and Golladay 1996), though they do not appear to be restricted to streams with shorter flow
durations (Stagliano 2005, Harris et al. 1999).

Although they are less widespread than many gastropods, freshwater mussels may be good
indicators of perennial flow, though some species in the Unionidae family (widespread in North
America) have been shown to survive prolonged periods of drying (Alyakrinskaya 2004).
However, Metcalf (1983) also found that a relatively short drought event (1 year) in southeast
Kansas resulted in a large die-off of unionid mussels. In addition, in a faunal study of the upper
Little Sioux River in Minnesota and Iowa (Bovbjerg et al. 1970), no unionid mussels were found
in the intermittent section of the river farthest upstream. Fingernail clams (Sphaeriidae) are not
treated as a perennial indicator taxon, but some support for this classification is found in
Lusardi et al. (2016) and Bovbjerg et al. (1970). However, Straka (2019) identified Pisidium as an
indicator of intermittent flow.

Mayflies

No mayfly families are considered to be an indicator of perennial flow in Blackburn and
Mazzacano (2012), although studies suggest that some taxa show a preference for perennial
flow (e.g., Isonychidae, King et al. 2015, Bovbjerg et al. 1970; Leptophlebiidae, Fritz and Dodds
2002, Miller and Golladay 1996, and Harris et al. 1999). Some studies support Baetidae as a
perennial indicator (e.g., Bovbjerg et al. 1970, Bonada et al. 2006, Miller and Golladay 1996,
Harris et al. 1999), while others suggest they prefer intermittent flow (e.g., Miller and Brasher
2011) or can be found in both flow types (Stagliano 2005). Straka et al. (2019) found numerous
mayfly indicator taxa of both intermittent/nearly perennial streams (e.g., Cloeon dipterm) and
perennial streams (e.g., Baetis rhodani).

Stoneflies

Several studies support the use of perlid stoneflies as indicators of perennial flow (e.g., Bonada
et al. 2006, Lusardi et al. 2016, Bogan 2017), but a few studies report them at very low
abundance in intermittent streams (e.g., del Rosario and Resh 2000, Miller and Golladay 1996).
Few studies in the AW and WM and no studies in the GP indicated if Pteronarcyidae were
collected, suggesting that this taxon may be too rare to be a useful indicator in these regions.

Although Capniidae are listed as an indicator of intermittent flow in Blackburn and Mazzacano
(2012), and this family is known to contain intermittent stream specialist taxa (e.g., Mesocapnia
arizonensis, Bogan 2017), intermittent indicators are not used in Nadeau (2015), and many taxa
in this family are found in perennial streams as well as intermittent (Bogan 2017).

In Czech streams, Straka et al. (2019) identified four indicators of intermittent flow (species in
Taeniopterygidae, Capniidae, Perlodidae, and Nemouridae), and numerous indicators of
perennial flow (species in Nemouridae, Perlidae, Perlodidae, Chloroperlidae, and Leuctridae).

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One Isoperla species (i.e., I. tripartita) is an indicator of intermittent flows, whereas two species
(i.e., I. oxlepis and I. rivularum) are indicators of perennial flows, suggesting that even genus-
level identifications may be too coarse to provide meaningful indication of flow duration.

Caddisflies

In the AW and WM, several studies support the use of Hydropsychidae, and to a lesser extent,
the other caddisfly families (i.e., Philopotamidae, Rhyacophilidae, and Glossosomatidae) as
indicators of perennial flow (Bonada et al. 2006, Miller and Brasher 2011, Erman and Erman
1995). In the GP, five studies support the use of caddisfly species in Hydropsychidae and
Philopotamidae as perennial indicators (Bramblett and Fausch 1991, Burk and Kenndedy 2013,
Fritz and Dodds 2002, Miller and Golladay 1996, and Stagliano 2005). In parts of the WM,
several studies suggested that additional families, such as Brachycentridae or Calamoceratidae,
may be good indicators of perennial flow (Bonada et al. 2006, Miller and Brasher 2011). Staka
et al. (2019) identified several indicator species for intermittent flows in Czech streams
(Beraeidae, Phryganeidae, and numerous species in Limnephilidae), and numerous indicators of
perennial flows in several families (including Glossosomatidae, Hydropsychidae, Limnephilidae,
Phryganeidae, Polycentropidae, and Rhyacophilidae).

Beetles

Several studies illustrate that elmid beetles show a strong preference for perennial streams, but
they are occasionally found in intermittent reaches as well (Burk and Kennedy 2013) —
particularly if those reaches are close to perennial waterbodies. De Jong et al. (2013) note that
Optioservus quadrimaculatus and Zaitzevia parvula are comparatively well-adapted to colonize
intermittent streams shortly after rewetting in the AW. Psephenidae are supported as an
indicator of perennial flow in Bonada et al. (2006) and King et al. (2015). Several aquatic beetle
families could be indicators of intermittent flow (e.g., Hydrophilidae: Bonada et al. 2006, Bogan
and Lytle 2007), and some are documented from ephemeral streams (De Jong et al. 2015).
Straka et al. (2019) identified several indicators of intermittent flow in Czech streams (mostly
Dytiscidae, Hydrophilidae, Helophoridae, and Hydraenidae), as well as of perennial streams
(several Elimdae, as well as Dytiscidae, Gryinidae, Hydraenidae, and Scirtidae).

Odonata

Several studies support the use of Gomphidae and Cordulegastridae as indicators of perennial
flow (e.g., Bonada et al. 2006, King et al. 2015). Straka et al. (2019) identified a Coenagrionidae
species to be indicative of intermittent flows in Czech streams; while they found no Odonata
taxa to be indicative of perennial flows, Cordulegastrid taxa were excluded from intermittent
streams (in agreement with Blackburn and Mazzacano 2012), whereas Calopterygidae were
more widespread (in disagreement with Blackburn and Mazzacano 2012). In the GP, Fritz and
Dodds (2002), Buchholtz and Buchholtz (1971), and Bovbjerg et al. (1970) found representatives
from Calopterygidae (Calopteryx maculata) and Coenagrionidae (Argia plana, Enallagma sp.,
Ischnura sp.) to be associated with perennial streams.

-------
Megaloptera

Corydalidae are listed as an indicator of perennial streams in the PNW (Blackburn and
Mazzacano 2012), but some reports from montane regions in the arid southwest (e.g., Bogan
and Lytle 2007) considered them to be indicative of intermittent flow. Cover et al. (2015)
describes two genus-groups within this family; the Neohermes-Protochauliodes group, which is
well adapted to intermittency by building hyporheic aestivation chambers to survive the dry
period (Figure 11), and the Orohermes-Dysmicohermes group, which does not burrow and is
therefore restricted to perennial streams. Distinguishing the two genus-groups in the field may
be possible, as the Neohermes-Protochouliodes group has distinctive head patterns in late
in stars (M. Cover, personal communication).

Figure 11, Neohermes aestivation chamber in a dry streambed in Arizona; the red box

indicates the area shown in the right photo (courtesy M.T. Bogan).

Diptera

Canedo-Argiielles et al. (2016) suggest that the diverse genera within Chironomidae may have
strong preferences for certain flow duration conditions, which is supported by several other
studies (e.g., Bonada et al. 2006, Miller and Brasher 2011). Herbst et al, (2019) found numerous
midge taxa associated with perennial flows, while other taxa were associated with intermittent
flows. In the GP, Chironomidae were one of the most abundant and cosmopolitan taxa in both
perennial and intermittent streams (Miller and Golladay 1996, Vander Vorste et al, 2008,

Vander Vorste 2010). Fritz and Dodds (2002) also found that families in the Brachycera
suborder (Phoridae, Sepsidae, and Scathophagidae) were generally associated with intermittent
streams. However, challenges with identifying this group in the field may make them
impractical for use in a field-based, rapid flow duration assessment method.

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Other aquatic invertebrates

In their study of Czech streams, Straka et al. (2019) identified several non-insect indicators of
intermittent streams, including the flatworm Mesastoma, the nematomorph Gordius, several
oligochaetes and leeches, and the isopod Asllus aquaticus. They also found numerous non-
insect indicators of perennial flows, such as several flatworm species (e.g., Dugesia, Polycelis),
several oligochaetes and leeches, the Hydracarina mites, and the amphipod Gammarus
fossarum. In Stagliano (2005), a suite of crustaceans is given as indicative of intermittent stream
ecosystems in the northern GP that have fishless pools. These taxa (see Table 6; fairy, clam, and
tadpole shrimps, ostracodes, copepods, and cladocerans) have resting egg stages that can resist
dry periods for a year or more. However, most of the indicative taxa are small and likely hard to
identify easily in the field, though the shrimps may allow for field sampling/identification.

Birnbaum et al. (2007) found that crayfish of the Cambaridae family inhabited intermittent
streams in central Texas, even during low to no flow conditions in summer. However, as
documented by Bovbjerg (1952; 1970) in northeast Illinois and the Little Sioux River headwaters
in Minnesota and Iowa, certain species of Cambaridae such as Faxonius propinquus (nee
Orconectes propinquus) and F. virilis (nee O. virilis) are more likely to be found in oxygen rich
flowing stream systems and are replaced by other members of the Cambaridae, such as F.
immunis (nee O. immunis) and Fallicambarus fodiens (nee Cambarus fodiens), that are better
able to withstand lower oxygen levels in slow-moving or pool habitats.

4.3.2 Algae

Algal biofilm, mats and other macroalgal forms are evident in most streams within a week of
the onset of flow (even 1 day, in the case of biofilms), and thus their presence may not always
be a good indicator of perennial or intermittent flow (Benenati et al. 1998, Robson et al. 2008,
Corcoll et al. 2015). However, most studies suggest that macroalgal growth in the first two
weeks after flow onset may be limited, particularly in hydrologically isolated systems without
access to perennial refugia (Robson et al. 2008). Thus, the abundance, rather than the presence
of macroalgal forms may be an effective indicator of flow duration.

Taxonomic identification of most algal species is difficult in the field, and they are therefore ill
suited for use as a field-based flow duration indicator. However, several studies suggest that
there are flow-duration affinities for several groups. For example, Benenati et al. (1998) showed
that the macroalga Cladophora tends to dominate in perennial streams, while diatoms and the
filamentous cyanobacterium Oscillatoria dominate in intermittent streams. Certain macroalgal
groups are readily identifiable in the field (Entwisle et al. 1997), potentially providing sufficient
information to inform flow duration assessment.

Dormant algal propagules may accumulate in the dry streambed and be resuscitated in lab
conditions. This approach has been proposed as a way to assess ecological conditions of dry
lakes and streambeds (Carvalho et al. 2002, Robson 2008), and could be used to assess flow

-------
duration. But because of the intensive nature of this approach, it is not well suited for a rapid
flow duration assessment method.

4.3.3 Bryophytes

The presence of "streamer mosses" is an indicator of intermittent or perennial flow duration in
Topping et al. (2009). Several studies support this use (Fritz et al. 2009, Cole et al. 2010), and a
number of taxa have been designated in terms of moisture preferences (e.g., Appendix A in
Fritz et al. 2009). Vieira et al. (2012, 2016) identified bryophyte community types characteristic
of intermittent and perennial rivers in Mediterranean Europe. They found that intermittent
rivers were dominated by drought tolerant taxa (e.g., Scorpiurium), and upright acrocarpous
annual forms, while perennial streams had more prostrate pleurocarpic perennial mats.

4.3.4 Riparian and wetland vascular plants

The presence of wetland indicator plants is an important indicator of flow duration in several
methods, especially in Nadeau (2015), where it may be the most important indicator in a dry
stream reach. An advantage of riparian plants over other biological indicators of flow duration
is that they are non-motile organisms, some having very long lifespans (i.e., decades).
Therefore, they are well suited to reflect local, long-term flow conditions in a way that fish or
invertebrates may not.

Several studies show a very strong relationship between flow duration and plant communities
(e.g., Caskey et al. 2015, Stromberg et al. 2007). Caskey et al. (2015) showed a decrease in
wetland plant occurance after diversion of perennial flow along stream reaches in the Routt
National Forest, CO (within the WM). Reynolds and Shafroth (2017) noted a number of plant
species indicative of perennial versus intermittent flow regimes in high and low elevation
streams in the Colorado Basin. Although that study did not identify ephemeral streams, the
authors report that the driest streams in their study were dominated by upland plants, such as
sagebrush and juniper (Lindsay Reyonlds, personal communication). Thus, the taxonomic
composition of riparian and wetland plants may be an effective indicator of flow duration.
Table 9 shows potential indicator species from these WM studies, included here because some
species have distributions that extend into or encompass the GP.

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Table 9. Vegetation associated with flow-duration classes.

Source

Region

Notes

Perennial

Intermittent

Caskey et
al. (2015)

Colorado
Rocky Mtns. -
Routt NF

Flow diversion
experiment,
summarizing
vegetation changes
above and below
diversions

Associated taxa (labeled
as obligate wetland
species): Carex utriculata,
Mertensia ciliate, Salix
planifolia, Salix wolfii,
Veronica americana

Reynolds
and

Shafroth
(2017)

Upper
Colorado
River Basin

Characteristic
riparian plants
associated with high
and low elevation
perennial and
intermittent streams

Associated taxa (low
elevation):

Rhus trilobata, Betula
occidentalis, Carex
nebrascensis, Juncus
torreyi, Rosa woodsia,
Equisetum arvense

Associated taxa (low
elevation):

Ericameria nauseosa,
Atriplex canescens,
Sporobolus cryptandrus,
Gutierrezia sarothrae

4.3.5 Vertebrates

Several flow duration assessment methods use the presence of vertebrates as indicators of
perennial or intermittent flow. Nadeau (2015), NCDWQ (2010), and Topping et al. (2009) use
the presence offish as a biological flow duration indicator. Generally, the GP is characterized by
naturally fluctuating flows from cycles of drought and flood that produce isolated perennial and
intermittent pools that serve as important refugia for fish during dry periods. While there are
likely no indicator species of fish that are restricted to intermittently or ephemerally flowing
streams in the GP, there are species that can better withstand environmental extremes and
may be more likely to be found in isolated pool habitats. Table 10 summarizes studies found
during this literature review that were conducted in the GP that compared or characterized fish
community composition in perennial and intermittent/ephemeral streams.

Table 10. Great Plains studies offish in different streamflow duration classes.

Source

Region

Notes

Perennial

Intermittent/
Ephemeral

Anderson et

North-central

Characterized fish at

Species found only

Species found only at

al. (1983)

Texas (Brazos

intermittent site

below dam:

upstream, intermittent

River)

above Possum

orangethroat and dusky

site: emerald shiner, sand

Kingdom Dam and

darters, central

shiner, plains minnow,

perennial sites below

stoneroller, bluntnose

speckled chub, and Red

minnow, blacktail

River pupfish

shiner, brook silverside,

and blackstripe

topminnow

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Source

Region

Notes

Perennial

Intermittent/
Ephemeral

Bramblett

Southeastern

Habitat and biota

Species more associated

Generalist fishes that favor

and Fausch

Colorado -

descriptions;

with perennial river

both intermittent and

(1991)

Purgatoire

tributaries not given

sites: red shiner, sand

perennial sites: fathead

River and 10

a definitive flow

shiner, flathead chub,

minnow and green sunfish

tributaries

classification

longnose dace, channel
catfish

Falke et al.

Northeastern

3 segments of River:

Not Applicable (N/A)

Authors found that fathead

(2012)

Colorado

perennial (fed by

minnow was the best

(Arikaree

aquifer),

colonizer of formerly dry

River)

intermittent, and
ephemeral (largely
due to pumping)

sites.

Fausch and

Southeastern

Characterized fish

N/A

Taxa associated more with

Bramblett

Colorado -

community

drier, intermittent sites:

(1991)

Purgatoire

composition of

fathead minnow, central

River and 10

perennial river sites

stoneroller, white sucker,

tributaries

and intermittent
tributary sites

black bullhead, and green
sunfish

Smith and

Southern

Sampled perennial,

Species most associated

Taxa most associated with

Powell

Oklahoma

intermittent, and

with perennial sites:

ephemeral sites: fathead

(1971)

ephemeral sections

Mississippi silverside,

minnow, golden shiner,

of Brier Creek,

common logperch,

and green sunfish

upstream and

blacktail shiner, white

downstream of Lake

crappie, shad,

Texoma

orangethroat darter

Ostrand

North-central

Characterized fish

N/A

Cyprinodontids and

and Wilde

Texas(upper

assemblage in

mosquito fish tended to

(2004)

Brazos River

isolated pools in an

maintain populations or

drainage)

intermittent system

increase in abundance as
pools dried, while
sharpnose shiner, plains
minnow, smalleye shiner,
plains killfish, Red River
pupfish, and red shiner all
decreased in population

The list of amphibian and reptile species used in Nadeau (2015) should be updated to include
taxa found in the GP through consultation with regional experts. Habitat preferences of taxa
specific to the GP will need to be developed if they are to be used as an indicator of flow
duration classes. For instance, in its Habitat Management Guidelines for the Midwest, Partners
in Amphibian and Reptile Conservation (Kingsbury and Gibson 2012) identify those species that
are most characteristic of certain stream habitats, for all or part of their life cycle (Table 11).
From a GP perspective, the 'midwest' in this context includes the Dakotas, Iowa, Illinois, Kansas,
Michigan, Minnesota, Missouri, Nebraska, and Wisconsin.

-------
Table 11. Characteristic reptiles and amphibian species of different types of stream habitats in
the Midwest (Kingsbury and Gibson 2012).

Aquatic Habitat

Characteristic Species*

Notes

Small streams,
springs, and seeps

Salamanders: four-toed, long-tailed,
eastern red-backed
Frogs: green, pickerel
Snakes: queen, northern watersnake

Small streams likely include those that are
intermittent; while springs and seeps are
generally fed by groundwater, they are
often isolated from other bodies of water
by terrestrial habitats

Rivers and large
streams

Salamander: mudpuppy+

Turtles: alligator snapping, smooth
softshell, spiny softshell, northern
map, wood

Snakes: eastern ribbonsnake,
northern watersnake, diamond-
backed watersnake, queen, red-bellied
mudsnake

Generally perennial systems. The
mudpuppy is a truly aquatic species that
requires water throughout its life cycle,
while many of the turtles leave the water
only to lay eggs. Two of the snake species
overlap from smaller streams, though all
the snakes here would be considered semi-
aquatic.

*Only includes those species that have ranges overlapping the GP
+Gilled throughout life cycle, aquatic only

In its headwater stream assessment method, Ohio EPA (2012) stipulates salamander species
that are indicators of perennial flow (generally those with larval stages longer than 12 months),
as well as those that can tolerate intermittent flow. Many of the species listed do not have
ranges that include the GP. One perennial indicator species, the longtailed salamander (Eurycea
longicauda), can be found in parts of IL and MO that are included in the GP, though it is noted
that some populations of this species have larval periods that are shorter than 12 months, and
Kingsbury and Gibson (2012) denotes this species as characteristic of smaller streams that have
a higher likelihood of being intermittent. Species given as tolerating intermittent flow and that
are also found in the GP include members of Ambystoma such as A. tigrinum (eastern tiger
salamander) and A. texanum (smallmouth salamander), as well as Hemidactylium scutatum
(four-toed salamander).

Painted turtles (Chrysemys picta) occur from the humid east coast through the northern Great
Plains and into the PNW. They are generally associated with permanent lentic habitats. In parts
of Iowa, they co-occur with the yellow mud turtle (Kinosternon flavescens), whose range in
Iowa is isolated from its usual range in the southern GP. Christiansen and Bickham (1989)
documented that when a lake these turtles were using completely dried, painted turtles moved
to remaining water sources (including a stream type habitats), but mud turtles would not. The
authors concluded that mud turtles began terrestrial estivation early, a behavior which is likely
a hallmark of the drier environment in which they evolved. Therefore, turtles with these types
of behavioral strategies may be poor flow duration indicators.

6.2 PROPOSED INDICATORS

Based on the above discussion, as well as study goals, we will largely evaluate indicators used in
the Pacific Northwest (Nadeau 2015) and New Mexico (NMED 2011) methods for the Great

-------
Plains. However, additional indicators with positive evidence for determining flow duration in

the primary literature, as well as any other priority indicators from Table 4 will also be included:

Geomorphological indicators

• Slope (Nadeau 2015)

• Sinuousity (NMED 2011)

• Floodplain and channel dimensions (aka, entrenchment ratio; NMED 2011)

• In-channel structure/riffle-pool sequence (NMED 2011)

• Substrate sorting (NMED 2011)

Hydrologic indicators

• Water in channel (NMED 2011); includes observations of hyporheic flow and isolated
pools

• Hydric soils (NMED 2011); includes sampling of soil moisture and texture

• Sediment on plants and debris (NMED 2011)

• Seeps and springs (NMED 2011)

• Number of woody jams within 10 m of the reach (Mersel and Lichvar 2014)

Biological indicators

Aquatic macroinvertebrates

• Presence of aquatic macroinvertebrates (Nadeau 2015). Early instars, partial terrestrial
taxa, and aerially dispersing life stages will be noted separately, if encountered.

• Abundance of mayflies (Nadeau 2015). Again, early instars will be ignored.

• Presence of perennial indicator taxa (Nadeau 2015). To facilitate this indicator, benthic
macroinvertebrates will be identified to the following taxonomic levels:

o Family: Aquatic Insects and Mollusks (with the exception of Corydalidae, which is

identified to genus-groups following Cover et al. 2015)
o Superorder or Order: Aquatic Mites and Crustaceans
o Phylum or Class (if possible): Aquatic Annelida and others
Every taxon that requires identification to the family level (i.e., aquatic insects and
mollusks) will be collected for laboratory confirmation of field identifications.
Additionally, whenever the identity of a specimen that requires family level ID is
unknown or uncertain, vouchers will be collected to determine identification in the
laboratory.

Algae

• Presence of filamentous algae (NMED 2011)

• Presence of live or dead algal mats (Topping et al. 2009)

-------
Bryophytes

• Presence of streamer mosses (Topping et al. 2009)

• Presence of liverworts (Fritz et al. 2009, Vieira et al. 2016)

• Presence of pleurocarp and acrocarp bryophytes in the channel and banks (Fritz et al.
2009, Vieira etal.2016)

Wetland and riparian plants

• Presence of FACW, OBL, and SAV plants, following Nadeau (2015). The regional wetland
plant lists encompassing the Great Plains (Lichvar et al. 2016) will be used.

• Absence of rooted vegetation in thalweg (NMED 2011)

• Vegetation differences between riparian zone and adjacent uplands (NMED 2011)
Vertebrates

• Presence offish, reptiles and amphibians (Nadeau 2015)

• Presence of fish (NMED 2011)

6.0 BIBLIOGRAPHY

6.1 Flow duration assessment methods

Here we present the sources reviewed for methods or method validation in determining flow
duration classes. Methods that were excluded based on the criteria in Figure 3 are presented
separately; rationale for exclusion is provided in "Notes" for each entry. Where applicable,
validation studies or studies associated with the development of a method are listed under
"Related Sources".

Europe

Gallart, F., Cid, N., Latron, J., Llorens, P., Bonada, N., Jeuffroy, J., ... Prat, N. (2017). TREHS: An
open-access software tool for investigating and evaluating temporary river regimes as a first
step for their ecological status assessment. The Science of the Total Environment, 607-608, 519-
540. https://doi.Org/10.1016/i.scitotenv.2017.06.209

Related Sources

Belmar, O., Velasco, J., & Martinez-Capel, F. (2011). Hydrological classification of natural
flow regimes to support environmental flow assessments in intensively regulated
Mediterranean rivers, Segura River Basin (Spain). Environmental Management, 47(5),
992-1004. https://doi.org/10.1007/sQ0267-011-9661-0

Gallart, F., Llorens, P., Latron, J., Cid, N., Rieradevall, M., & Prat, N. (2016). Validating
alternative methodologies to estimate the regime of temporary rivers when flow data

-------
are unavailable. The Science of the Total Environment, 565, 1001-1010.
https://doi.Org/10.1016/i.scitotenv.2016.05.116

Gallart, F., Prat, N., Garca-Roger, E. M., Latron, J., Rieradevall, M., Llorens, P., ...
Froebrich, J. (2012). A novel approach to analyzing the regimes of temporary streams in
relation to their controls on the composition and structure of aquatic biota. Hydrology
and Earth System Sciences, 16(9), 3165-3182. https://doi.org/10.5194/hess-16-3165-
2012

Prat, N., Gallart, F., Von Schiller, D., Polesello, S., Garcfa-Roger, E. M., Latron, J., ...
Froebrich, J. (2014). THE MIRAGE TOOLBOX: AN INTEGRATED ASSESSMENT TOOL FOR
TEMPORARY STREAMS. River Research and Applications, 30(10), 1318-1334.
https://doi.org/10.10Q2/rra.2757

Straka, M., Polasek, M., Syrovatka, V., Stubbington, R., Zahradkova, S., Nemejcova, D., ... Paril,
P. (2019). Recognition of stream drying based on benthic macroinvertebrates: A new tool in
Central Europe. Ecological Indicators, 106,105486.

New Mexico

Surface Water Quality Bureau, New Mexico Environment Department. (2011). HYDROLOGY
PROTOCOL FOR THE DETERMINATION OF USES SUPPORTED BY EPHEMERAL, INTERMITTENT)
AND PERENNIAL WATERS. Retrieved from

https://www.env.nm.gov/swqb/documents/swqbdocs/MAS/Hvdrology/Hvd rologyProtocolAPP
RQVED05-2011.pdf

Related Sources

Surface Water Quality Bureau, New Mexico Environment Department. (2011).
HYDROLOGY PROTOCOL FOR THE DETERMINATION OF USES SUPPORTED BY
EPHEMERAL, INTERMITTENT; AND PERENNIAL WATERS (Appendix 1). Retrieved from:
https://www.env.nm.gov/swqb/documents/swqbdocs/MAS/Hvdrology/Appendixl.pdf

Surface Water Quality Bureau, New Mexico Environment Department. (2012).

Hydrology Protocol Use Attainability Analysis for an Ephemeral Stream (Cover Sheet, Dec
2012). Retrieved from:

https://www.env.nm.gov/swqb/documents/swqbdocs/MAS/Hvdrology/Hvd rologyCover
SheetREVDec2012.docx

Surface Water Quality Bureau, New Mexico Environment Department. (2011).

Hydrology Determination Field Sheets (May 2011). Retrieved from:
https://www.env.nm.gov/swqb/documents/swqbdocs/MAS/Hvdrology/Hvd rologyFieldS
heetsREVMay2011.docx

-------
North Carolina

NC Division of Water Quality. (2010). Methodology for Identification of Intermittent and
Perennial Streams and their Origins (Version 4.11). North Carolina Department of Environment
and Natural Resources. Retrieved from:

http://portal.ncdenr.org/web/wq/swp/ws/401/waterresources/streamdeterminations
Related Sources

Fritz, K. M., Wenerick, W. R., & Kostich, M. S. (2013). A validation study of a rapid field-
based rating system for discriminating among flow permanence classes of headwater
streams in South Carolina. Environmental Management, 52(5), 1286-1298.
https://doi.org/10.1007/sQ0267-013-0158-x

Pacific Northwest. Arid West, and Western Mountains

Mazor, R.D., Topping, B., Nadeau, T.-L., Fritz, K.M., Kelso, J., Harrington, R., Beck, W., McCune,
K., Lowman, H., Allen, A., Leidy, R., Robb, J.T., and David, G.C.L. 2021a. User Manual for a Beta
Streamflow Duration Assessment Method for the Arid West of the United States. Version 1.0.
Document No. EPA-800-5-21001.

Mazor, R.D., Topping, B., Nadeau, T.-L., Fritz, K.M., Kelso, J., Harrington, R., Beck, W., McCune,
K., Allen, A., Leidy, R., Robb, J.T., David, G.C.L., and Tanner, L. 2021b. User Manual for a Beta
Streamflow Duration Assessment Method for the Western Mountains of the United States.
Version 1.0. Document No. EPA-840-B-21008.

Nadeau, T.-L. (2015). Streamflow Duration Assessment Method for the Pacific Northwest (No.
EPA 910-K-14-001). U.S. Environmental Protection Agency, Region 10, Seattle, WA.

Related Sources

Nadeau, T.-L. (2011). 2011 Streamflow Duration Assessment Method for Oregon (No.
EPA 910-R-11-002). U.S. Environmental Protection Agency, Region 10.

Nadeau, T.-L., Leibowitz, S. G., Wigington, P. J., Jr, Ebersole, J. L., Fritz, K. M., Coulombe,
R. A., Comeleo, R.L, Blocksom, K. A. (2015). Validation of rapid assessment methods to
determine streamflow duration classes in the Pacific Northwest, USA. Environmental
Management, 56(1), 34-53.

Topping, B. J. D., Nadeau, T.-L., & Turaski, M. R. (2009). Oregon Streamflow Duration
Assessment Method Interim Version - Interim version (March 2009).

Savage, N.L., & Rabe, F.W. (1979). Stream types in Idaho: an approach to classification of
streams in natural areas. Biological Conservation 15.

-------
Temperate U.S.

Fritz, K. M., Johnson, B. R., & Walters, D. M. (2006). Field Operations Manual for Assessing the
Hydrologic Permanence and Ecological Condition of Headwater Streams (No. EPA/600/ R-
06/126). U.S. Environmental Protection Agency, Office of Research and Development,
Washington DC. Retrieved from: https://www.epa.gov/sites/production/files/2015-
11/documents/manual for assessing hydrologic permanence - headwater streams.pdf

Related Sources

Fritz, K. M., Johnson, B. R., & Walters, D. M. (2008). Physical indicators of hydrologic
permanence in forested headwater streams. Journal of the North American
BenthologicalSociety, 27(3), 690-704.

Johnson, B. R., Fritz, K. M., Blocksom, K. A., & Walters, D. M. (2009). Larval
salamanders and channel geomorphology are indicators of hydrologic permanence in
forested headwater streams. Ecological Indicators, 9(1), 150-159.

Roy, A. H., Dybas, A. L., Fritz, K. M., & Lubbers, H. R. (2009). Urbanization affects the
extent and hydrologic permanence of headwater streams in a midwestern US
metropolitan area. Journal of the North American Benthological Society, 28(4), 911-928.

Kentucky

Svec, J. R., Kolka, R. K., & Stringer, J. W. (2005). Defining perennial, intermittent, and ephemeral
channels in Eastern Kentucky: Application to forestry best management practices. Forest
Ecology and Management, 214(1), 170-182. https://doi.Org/10.1016/i.foreco.2005.04.008

Ohio

Ohio EPA. (2012). Field Evaluation Manual for Ohio's Primary Headwater Streams (Version 3.0).
Ohio EPA, Division of Surface Water. Retrieved from:
http://epa.ohio.gov/portals/35/wqs/headwaters/PHWHManual 2012.pdf

Canada

McCleary, R., Haslett, S., & Christie, K. (2012). Field Manual for Erosion-Based Channel
Classification. Foothills Research Institute. Retrieved from:

https://friresearch.ca/sites/default/files/null/WP_2012_ll_Manual_FieldManual_ErosionBase
d_Channel_Class_Vers_7.0.pdf

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Excluded Methods

Berhanu, B., Seleshi, Y., Demisse, S. S., & Melesse, A. M. (2015). Flow Regime Classification and
Hydrological Characterization: A Case Study of Ethiopian Rivers. WATER, 7(6), 3149-3165.
https://doi.org/10.3390/w7063149

Rational for Exclusion: Low utility. Analysis of flow duration class requires flow metrics
extracted from observed or modeled daily flow data and is therefore not a rapid method.

Berkowitz, J., Casper, A. F., & Noble, C. (2011). A multiple watershed field test of
hydrogeomorphic functional assessment of headwater streams—Variability in field
measurements between independent teams. Ecological Indicators, 11(5), 1472-1475.
https://doi.Org/10.1016/i.ecolind.2011.01.004

Rational for Exclusion: Low applicability and utility. This study may be useful in
estimating expected errors in field measured hydrogeomorphic flow duration indicators,
but there is no direct application for these indicators in direct assessment of flow
duration.

Kennard, M. J., Pusey, B. J., Olden, J. D., Mackay, S. J., Stein, J. L., & Marsh, N. (2010).
Classification of natural flow regimes in Australia to support environmental flow management.
Freshwater Biology, 55(1), 171-193. https://doi.Org/10.llll/i.1365-2427.2009.02307.x

Rational for Exclusion: Low utility. Methods of determining hydrologic regime here rely
upon mean daily discharge data.

Noble, C. V., Berkowitz, J., & Spence, J. (2010). Operational Draft Regional Guidebook for the
Functional Assessment of High-gradient Ephemeral and Intermittent Headwater Streams in
Western West Virginia and Eastern Kentucky. US Army Corps of Engineers, Vicksburg. Retrieved
from

http://www.lrh.usace.armv.mil/Portals/38/docs/Operational%20Draft%20Regional%20Guidebo
okl.pdf

Rational for Exclusion: Low applicability. This study assesses indicators of habitat
capacity and function at streams with flow duration known from intensive hydrologic
data.

Porras, A., & Scoggins, M. (2013). The Flow Permanence Index: A Statistical Assessment of Flow
Regime in Austin Streams. City of Austin, Watershed Protection Department. Retrieved from
http://www.austintexas.gov/watershed protection/publications/document.cfm?id=213560

Rational for Exclusion: Low utility. The methodology relies on regionally specific
hydrologic models, rather than field indicators.

Trubilowicz, J. W., Moore, R. D., & Buttle, J. M. (2013). Prediction of stream-flow regime using
ecological classification zones. Hydrological Processes, 27(13), 1935-1944.
https://doi.org/10.1002/hyp.9874

-------
Rational for Exclusion: Low utility. The methodology relies on regionally specific
hydrologic models, rather than field indicators.

6.2 Indicators

Biology
Algae

Benenati, P. L., Shannon, J. P., & Blinn, D. W. (1998). Desiccation and recolonization of
phytobenthos in a regulated desert river: Colorado River at Lees Ferry, Arizona, USA. Regulated
Rivers: Research & Management, 14(6), 519-532.

Carvalho, L., Bennion, H., Dawson, H., Furse, M., Gunn, I., Hughes, R., ... Others. (2002). Nutrient
conditions for different levels of ecological status and biological quality in surface waters (Phase
I). Environment, 2002.

Corcoll, N., Casellas, M., Huerta, B., Guasch, H., Acuna, V., Rodrfguez-Mozaz, S., ... Sabater, S.
(2015). Effects of flow intermittency and pharmaceutical exposure on the structure and
metabolism of stream biofilms. The Science of the Total Environment, 503-504,159-170.

Entwisle, T. J., Sonneman, J. A., & Lewis, S. H. (1997). Freshwater algae in Australia. Sainty &
Associates.

Gillett, N. D., Pan, Y., Manoylov, K. M., Stancheva, R., & Weilhoefer, C. L. (2011). THE POTENTIAL
INDICATOR VALUE OF RARE TAX A RICHNESS IN DIATOM-BASED STREAM BIOASSESSMENT 1.
Journal of Phycology, 47(3), 471-482.

Robson, B. J., Matthews, T. Y. G., Lind, P. R., & Thomas, N. A. (2008). Pathways for algal
recolonization in seasonally flowing streams. Freshwater Biology, 53(12), 2385-2401.

Shaver, M. L., Shannon, J. P., Wilson, K. P., Benenati, P. L., & Blinn, D. W. (1997). Effects of
suspended sediment and desiccation on the benthic tailwater community in the Colorado River,
USA. Hydrobiologia, 357(1), 63-72.

Aquatic Macroinvertebrates

Alyakrinskaya, I. O. (2004). Resistance to drying in aquatic mollusks. Biology Bulletin, 31(3).

Birnbaum, J.S., Winemiller, K.O., Shen, L., Munster, C.L., Wilcox, B.P., and Wilkins, R.N. (2007).
Associations of watershed vegetation and environmental variables with fish and crayfish

-------
assemblages in headwater streams of the Pedernales River, Texas. River Research and
Applications, 23, 979-996.

Blackburn, M., & Mazzacano, C. (2012). Using aquatic macroinvertebrates as indicators of
streamflow duration (Washington and Idaho Indicators). Prepared for the U.S. Environmental
Protection Agency, Region 10.

Bogan, M. T. (2017). Hurry up and wait: life cycle and distribution of an intermittent stream
specialist (Mesocapnia arizonensis). Freshwater Science 36(4), 805-815.

Bogan, M. T., Boersma, K. S., & Lytle, D. A. (2013). Flow intermittency alters longitudinal
patterns of invertebrate diversity and assemblage composition in an arid-land stream network.
Freshwater Biology, 58(5), 1016-1028.

Bogan, M.T., & Lytle, D.A. (2007). Seasonal flow variation allows 'time-sharing' by disparate
aquatic insect communities in montane desert streams. Freshwater Biology, 52(2), 290-304.

Bonada, N., Rieradevall, M., Prat, N., & Resh, V. H. (2006). Benthic macroinvertebrate
assemblages and macrohabitat connectivity in Mediterranean-climate streams of northern
California. Journal of the North American Benthological Society, 25(1), 32-43.

Bovbjerg, R.V. (1952). Comparative ecology and physiology of the crayfish Orconectes
propinquus and Cambarus fodiens. Physiological Zoology, 25(1), 34-56.

Bovbjerg, R.V. (1970). Ecological isolation and competitive exclusion in two crayfish (Orconectes
virilis and Orconectes immunis). Ecology, 51(2), 225-236.

Bovbjerg, R.V., Pearsall, N.L., and Brackin, M.L. (1970). A preliminary faunal study of the upper
Little Sioux River. Proceedings of the Iowa Academy of Science, 77(27).

Bramblett, R. G., & Fausch, K. D. (1991). Fishes, macroinvertebrates, and aquatic habitats of the
Purgatoire River in Pinon Canyon, Colorado. The Southwestern Naturalist, 281-294.

Brasher, A. M. D., Albano, C. M., Close, R. N., Cannon, Q. H., & Miller, M. P. (2010).
Macroinvertebrate Communities and Habitat Characteristics in the Northern and Southern
Colorado Plateau Networks: Pilot Protocol Implementation. National Park Service, Fort Collins,
Colorado.

Buchholtz, C., and Buchholtz, C. (1974). Biological diversities in various ecosystems on the east
branch of the Vermilion River. Proceedings of the South Dakota Academy of Science, 53, 246-
253.

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Burk, R.A., & Kennedy, J.H. (2013). Invertebrate communities of groundwater dependent
refugia with varying hydrology and riparian cover during a supraseasonal drought. Journal of
Freshwater Ecology 28(2), 251-270.

Canedo-Arguelles, M., Bogan, M. T., Lytle, D. A., & Prat, N. (2016). Are Chironomidae (Diptera)
good indicators of water scarcity? Dryland streams as a case study. Ecological Indicators, 71,
155-162.

Cover, M. R., Seo, J. H., & Resh, V. H. (2015). Life History, Burrowing Behavior, and Distribution
of Neohermes filicornis (Megaloptera: Corydalidae), a Long-Lived Aquatic Insect in Intermittent
Streams. Western North American Naturalist/Brigham Young University, 75(4), 474-490.

De Jong, G. D., Canton, S. P., Lynch, J. S., & Murphy, M. (2015). Aquatic invertebrate and
vertebrate communities of ephemeral stream ecosystems in the arid southwestern United
States. The Southwestern Naturalist, 60(4), 349-359.

De Jong, G. D., Smith, E. R., & Conklin, D. J., JR. (2013). RIFFLE BEETLE COMMUNITIES OF
PERENNIAL AND INTERMITTENT STREAMS IN NORTHERN NEVADA, USA, WITH A NEW STATE
RECORD FOR OPTIOSERVUS CASTANEIPENNIS (FALL) (COLEOPTERA: ELMIDAE). The
Coleopterists' Bulletin, 67(3), 1-9.

del Rosario, R. B., & Resh, V. H. (2000). Invertebrates in intermittent and perennial streams: is
the hyporheic zone a refuge from drying? Journal of the North American Benthological Society,
19(4), 680-696.

Erman, N. A., & Erman, D. C. (1995). Spring permanence, Trichoptera species richness, and the
role of drought. Journal of the Kansas Entomological Society, 68(2), 50-64.

Fritz, K.M. & Dodds, W.K. (2005). Harshness: characterisation of intermittent stream habitat
over space and time. Marine and Freshwater Research 56, 13-23.

Fritz, K.M. & Dodds, W.K. (2004). Resistance and resilence of macroinvertebrate assemblages to
drying and flood in a tallgrass prairie stream system. Hydrobiologia 527, 99-112.

Fritz, K.M. & Dodds, W.K. (2002). Macroinvertebrate assemblage structure across a tallgrass
pariaire stream landscape. Archivfur Hydrobiologie 154(1), 79-102.

Harrel R.C., & Dorris, T.C. (1968). Stream order, morphometry, physicochemical conditions, and
community structure of benthic macroinvertebrates in an intermittent stream system.

American Midland Naturalist 80(1), 220-251.

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Harris M.A., Kondratieff B.C., & Boyle, T.P. (1999). Macroinvertebrate community structure of
three prairie streams. Journal of the Kansas Entomological Society 72(4), 402-425.

Herbst, D. B., Bogan, M. T., & Lusardi, R. A. (2008). Low specific conductivity limits growth and
survival of the New Zealand mud snail from the Upper Owens River, California. Western North
American Naturalist/ Brigham Young University, 68(3), 324-333.

Herbst, D. B., Cooper, S. D., Medhurst, R. B., Wiseman, S. W., & Hunsaker, C. T. (2019). Drought
ecohydrology alters the structure and function of benthic invertebrate communities in
mountain streams. Freshwater Biology, 64(5), 886-902.

King, R. S., Scoggins, M., & Porras, A. (2015). Stream biodiversity is disproportionately lost to
urbanization when flow permanence declines: evidence from southwestern North America.
Freshwater Science, 35(1), 340-352.

Lusardi, R. A., Bogan, M. T., Moyle, P. B., & Dahlgren, R. A. (2016). Environment shapes
invertebrate assemblage structure differences between volcanic spring-fed and runoff rivers in
northern California. Freshwater Science, 35(3), 1010-1022.

Mazzacano, C., & Black, S.H. (2008). Using Aquatic Macroinvertebrates as Indicators of
Streamflow Duration. The Xerces Society for Invertebrate Conservation.

Metcalf, A.L. (1983). Mortality in unionacean mussels in a year of drought. Transactions of the
Kansas Academy of Science 86(2-3), 89-92.

Miller, M. P., & Brasher, A. (2011). Differences in macroinvertebrate community structure in
streams and rivers with different hydrologic regimes in the semi-arid Colorado Plateau. River
Systems, 19(3), 225-238.

Miller, A.M., & Golladay, S.W. (1996). Effects of spates and drying on macroinvertebrate
assemblages of an intermittent and a perennial prairie stream. Journal of the North American
Benthological Society 15(4), 670-689.

Stagliano, D.M. (2005). Aquatic Community Classification and Ecosystem Diversity in Montana's
Missouri River Watershed. Report to the Bureau of Land Management. Montana Natural
Heritage Program, Helena, MT.

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Vander Vorste R. (2010). Hydroperiod, Physicochemistry, and Seasonal Change of
Macroinvertebrate Communities in Intermittent Prairie Streams. Masters Thesis.

Vander Vorste R., Rasmussen, E., &Troelstrup, N.H. (2008). Family-level community structure of
insects inhabiting intermittent streams within the northern glaciated plains. Oak Lake Field
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Bryophytes

Cole, C., Stark, L. R., Bonine, M. L., & McLetchie, D. N. (2010). Transplant Survivorship of
Bryophyte Soil Crusts in the Mojave Desert. Restoration Ecology, 18(2), 198-205.

Fritz, K. M., Glime, J. M., Hribljan, J., & Greenwood, J. L. (2009). Can bryophytes be used to
characterize hydrologic permanence in forested headwater streams? Ecological Indicators, 9(4),
681-692.

Vieira, C., Aguiar, F. C., Portela, A. P., Monteiro, J., Raven, P. J., Holmes, N. T. H., ... Ferreira, M.
T. (2016). Bryophyte communities of Mediterranean Europe: a first approach to model their
potential distribution in highly seasonal rivers. Hydrobiologia, 1-17.

Vieira, C., Seneca, A., Sergio, C., & Ferreira, M. T. (2012). Bryophyte taxonomic and functional
groups as indicators of fine scale ecological gradients in mountain streams. Ecological
Indicators, 18, 98-107.

Vertebrates

Anderson, K.A., Beitinger, T.L. and Zimmerman, E.G., 1983. Forage fish assemblages in the
Brazos River upstream and downstream from Possum Kingdom Reservoir, Texas .Journal of
Freshwater Ecology, 2(l):81-88.

Bramblett, R. G., & Fausch, K. D. (1991). Fishes, macroinvertebrates, and aquatic habitats of the
Purgatoire River in Pinon Canyon, Colorado. The Southwestern Naturalist, 36(3), 281-294.

Christiansen, J.L. and Bickham, J.W., 1989. Possible historic effects of pond drying and winterkill
on the behavior of Kinosternon flavescens and Chrysemys picta. Journal of Herpetology,
23(1):91-94.

Falke, J.A., Bailey, L.L, Fausch, K.D., & Bestgen, K.R. (2012). Colonization and extinction in
dynamic habitats: an occupancy approach for a Great Plains stream assemblage. Ecology, 93(4),
858-867.

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Fausch, K.D., & Bramblett, R.B. (1991). Disturbance and fish communities in intermittent
tributaries of a western Great Plains River. Copeia (3), 659-674.

Fox, J. T., & Magoulick, D. D. (2019). Predicting hydrologic disturbance of streams using species
occurrence data. The Science of the Total Environment, 686, 254-263.

Harrel, R.C., Davis, B.J., & Dorris, T.C. (1967). Stream order and species diversity of fishes in an
intermittent Oklahoma stream. American Midland Naturalist, 78(2), 428-436.

Hughes, R. M., Herlihy, A. T., & Sifneos, J. C. (2015). Predicting aquatic vertebrate assemblages
from environmental variables at three multistate geographic extents of the western USA.
Ecological Indicators, 57, 546-556.

Kingsbury, B.A. and Gibson, J. [editors]. (2012). Habitat Management Guidelines for Amphibians
and Reptiles of the Midwestern United States. Partners in Amphibian and Reptile Conservation
Technical Publication HMG-1, 2nd edition, 155 pp. Retrieved from:
https://www.mwparc.org/products/habitat/MWHMG-Full.pdf

Meador, M.R. & Matthews, W.J. (1992). Spatial and temporal patterns in fish asssemblage
structure of an intermittent Texas stream. American Midland Naturalist 127(1), 106-114.

Ostrand, K.G. and Wilde, G.R. (2004). Changes in prairie stream fish assemblages restricted to
isolated streambed pools. American Fisheries Society 133,1329-1338.

Perkin, J.S., Gido, K.B., Cooper, A.R., Turner, T.F., Osborne, M.J., Johnson, E.R., & Mayes, K.B.
(2015). Fragmentation and dewatering transform Great Plains fish communities. Ecological
Monographs 85(1), 73-92.

Smith, C.L. and Powell, C.R. (1971). The summer fish communities of Brier Creek, Marshall
County, Oklahoma. American Museum Novitates; 2458,1-30.

Scheuerer J.A., Fausch, K.D., and Bestgen, K.R. (2003). Multiscale processes regulate brassy
minnow persistence in a Great Plains river. Transactions of the American Fisheries Society 132,
840-855.

Vegetation

Caskey, S. T., Blaschak, T. S., Wohl, E., Schnackenberg, E., Merritt, D. M., & Dwire, K. A. (2015).
Downstream effects of stream flow diversion on channel characteristics and riparian vegetation
in the Colorado Rocky Mountains, USA. Earth Surface Processes and Landforms, 40(5), 586-598.

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Reynolds, L.V., & Shafroth, P.B. (2017). Riparian plant composition along hydrologic gradients in
a dryland river basin and implications for a warming climate. Ecohydrology 10,1864.

Stromberg, J. C., Lite, S. J., Marler, R., Paradzick, C., Shafroth, P. B., Shorrock, D., ... White, M. S.
(2007). Altered stream-flow regimes and invasive plant species: the Tamarix case. Global
Ecology and Biogeography: A Journal of Macroecology, 16(3), 381-393.

Geomorphology

Allen, G. H., Pavelsky, T. M., Barefoot, E. A., Lamb, M. P., Butman, D., Tashie, A., & Gleason, C. J.
(2018). Similarity of stream width distributions across headwater systems. Nature
Communications, 9(1), 610.

Costigan, K.H., Daniels, M.D., Perkin, J.S., & Gido, K.B. (2014). Longitudinal variability in
hydraulic geometry and substrate characteristics of a Great Plains sand-bed river.
Geomorphology 210, 48-58.

Ford, T. D., & Pedley, H. M. (1996). A review of tufa and travertine deposits of the world. Earth-
Science Reviews, Vol. 41, pp. 117-175. https://doi.org/10.1016/s0012-8252(96)00030-x

Friedman, J. M., & Lee, V. J. (2002). EXTREME FLOODS, CHANNEL CHANGE, AND RIPARIAN
FORESTS ALONG EPHEMERAL STREAMS. Ecological Monographs, 72(3), 409-425.

Wohl, E., Egenhoff, D. & Larkin, K. (2009). Vanishing riverscapes: A review of historical channel
change on the western Great Plains, in James LA, SL Rathburn, and GR Whittecar, eds.,
Management and Restoration of Fluvial Systems with Broad Historical Changes and Human
Impacts: Geological Society of America Special Paper 451, p. 131-142.

Wright, J. S. (2000). Tufa accumulations in ephemeral streams: observations from The
Kimberley, north-west Australia. The Australian Geographer, 31(3), 333-347.

Hydrology

Abbe, T. B., & Montgomery, D. R. (1996). Large woody debris jams, channel hydraulics and
habitat formation in large rivers. Regulated Rivers: Research & Management, 12(2-3), 201-221.

Costigan, K.H., Daniels, M.D., & Dodds, W.K. (2015). Fundamental spatial and temporal
disconnections in the hydrology of an intermittent prairie headwater network. Journal of
Hydrology 522, 305-316.

Faustini, J. M., & Jones, J. A. (2003). Influence of large woody debris on channel morphology
and dynamics in steep, boulder-rich mountain streams, western Cascades, Oregon.
Geomorphology, 51(1), 187-205.

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Gurtz, M.E., Marzolf, G.R., Killingbeck, K.T., Smith, D.L., & McArthur, J.V. (1988). Hydrologic and
riparian influences on the import and storage of coarse particulate organic matter in a prairie
stream. Canadian Journal of Fisheries and Aquatic Sciences 45.

Hill, B.H., Gardner, T.J., & Ekisola, O.F. (1988). Breakdown of gallery forest leaf litter in
intermittent and perennial prairie streams. Southwestern Naturalist 33(3), 323-331.

Mersel, M. K., & Lichvar, R. W. (2014). A guide to ordinary high-water mark (OHWM)
delineation for non-perennial streams in the western mountains, valleys, and coast region of
the United States. ENGINEER RESEARCH AND DEVELOPMENT CENTER HANOVER NH COLD
REGIONS RESEARCH AND ENGINEERING LAB. Retrieved from https://erdc-
library.erdc.dren.mil/xmlui/bitstream/handle/11681/5501/ERDC-CRREL-TR-14-
13.pdf?sequence=l&isAllowed=y

Tate, C.M., & Gurtz, M.E. (1986). Comparison of mass loss, nutrients, and invertebrates
associated with Elm leaf litter decomposition in perennial and intermittent reaches of tallgrass
prairie streams. Southwestern Naturalist 31(4), 511-520.

OtherTopics

Caruso, B. S., & Haynes, J. (2011). Science and policy integration issues for stream and wetland
jurisdictional determinations in a semi-arid region of the western US. Wetlands Ecological
Management 19, 351-371.

Caruso, B. S., & Haynes, J. (2011). Biophysical-regulatory classification and profiling of streams
across management units and ecoregions. Journal of the American Water Resources Association
47(2), 386-407.

Caruso, B. S., & Haynes, J. (2010). Connectivity and Jurisdictional Issues for Rocky Mountains
and Great Plains Aquatic Resources. Wetlands, 30(5), 865-877.

Dodds, W.K., Gido, K., Whiles, M.R., Fritz, K.M., & Matthews, M.J. (2004). Life on the edge: The
ecology of Great Plains prairie streams. Bioscience 54(3).

Dodds, W.K., Gido, K., Whiles, M.R., Daniels, M.D., & Grudzinski, B.P. (2015). The stream biome
gradient concept: factors controlling lotic systems across broad biogeographic scales.
Freshwater Science 34(1), 1-19.

Fritz, K.M., Nadeau, T.-L., Kelso, J.E., Beck, W.S., Mazor, R.D., Harrington, R.A., & Topping, B.J.
(2020). Classifying streamflow duration: the scientific basis and an operational framework for
method development. Water, 12 (2545).

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Hill, B.H., and Gardner, T.J. (1987). Benthic metabolism in a perennial and an intermittent Texas
prairie stream. Southwestern Naturalist 32(3), 305-311.

Hill, B.H., Gardner, T.J., and Ekisola, O.F. (1992). Benthic organic matter dynamics in Texas
prairie streams. Hydrobiologia 242, 1-5.

Matthews, W.J. (1988). North American prairie streams as systems for ecological study. Journal
of the North American Benthological Society 7(4), 387-409.

McCune, K., & Mazor, R. (2021). Review of Flow Duration Methods and Indicators of Flow
Duration in the Scientific Literature: Western Mountains. Southern California Coastal Water
Research Project Technical Report 1222. Prepared for the U.S. Environmental Protection
Agency.

McCune, K., & Mazor, R. (2019). Review of Flow Duration Methods and Indicators of Flow
Duration in the Scientific Literature: Arid Southwest. Southern California Coastal Water
Research Project Technical Report 1063. Prepared for the U.S. Environmental Protection
Agency.

Wohl, E., Mersel, M.K., Allen, A.O., Fritz, K.M., Kichefski, S.L., Lichvar, R.W., Nadeau, T-L.,
Topping, B.J., Trier, P.H., & Vanderbilt, F.B. (2016). Synthesizing the Scientific Foundation for
Ordinary High-Water Mark Delineation in Fluvial Systems. ERDC/CRREL SR-16-5.

Zale, A.V., Leslie, D.M., Fisher, W.M., & Merrifield, S.G. (1989). The physicochemistry, flora, and
fauna of intermittent prairie streams: a review of the literature. US Fish and Wildlife Service
Biological Report 89(5). 44 pp.

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