States and Tribes Embrace 

Bioassessment and Biocriteria 

for Protecting Streams and 

Small Rivers

The miles of streams and small rivers assessed for biological condition ! increased from 65,000 in 1995 to almost 440,000 in 2001.

GROWTH OF THE NATION’S PROGRAMS

• More States, Tribes and other programs are using 

bioassessment and biocriteria than ever before for 

streams and small rivers

 - The number of programs using bioassessment has 

increased from 41 to 57.

 - Puerto Rico and the Nez Perce Tribe have programs 

under development.

• Use of Bioassessment in Water Resource Management 

programs has increased by more than 20%

 - All 50 states, the District of Columbia and the Ohio 

River Valley Water Sanitation Commission (ORSANCO) 

have incorporated bioassessment in their water resource 

management programs for streams and small rivers. 

MAKING PROGRESS WITH EPA SUPPORT

Since 1987, U.S. EPA has actively supported bioassessment programs 

and the development of biocriteria. A close and cooperative relationship 

between EPA and the state, tribal, territory, and interstate commission 

programs has resulted in more rigorous and standardized biological 

assessments. Signifi cant progress was revealed in a recent study 

jointly conducted by the Offi ce of Water (OW) and the Offi ce of 

Environmental Information (OEI). The detailed fi ndings have been 

published in Summary of Biological Assessment Programs and 

Biocriteria Development for States, Tribes, Territories, and Interstate 

Commissions: Streams and Wadeable Rivers (EPA-822-R-02-048), 

available on EPA’s web site at http://www.epa.gov/bioindicators. 

With this major progress on streams and small rivers, states, tribes, 

territories and interstate commissions can begin to focus on developing 

biocriteria for other water bodies (lakes, reservoirs, wetlands, estuaries, 

large rivers, intermittent and ephemeral streams) for which EPA has 

developed methods and guidance.

Biological assessments and criteria give the programs a tool for directly 

determining the health of their aquatic life resources, for improving 

aquatic life designated uses, and for setting biocriteria to protect 

those uses. Biocriteria act as the water body “response criteria” and 

complement chemical and other criteria designed to manage pollutants 

and other stressors introduced into the water body. 

Figure 1: Growth in Programs Using 

Bioassessment for Water Quality Management 

of Streams and Small Rivers.
BIOASSESSMENT

The presence, condition, numbers and types of 

fi sh, insects, algae, plants, and other organisms 

provide direct, accurate information about the 

health of water bodies. Biological assessments 

measure these factors and are the primary tool 

used to evaluate the condition of water bodies. 

Because biological communities are affected by 

all of the stressors to which they are exposed 

over time, bioassessments provide information 

on disturbances not always revealed by water 

chemistry or other measurements. 

With time and understanding, 

more states, tribes, and territories 

are realizing the benefi ts of using 

biological information in their 

water management programs.

Bioassessments help states, tribes, and other 

programs develop expectations for biological 

conditions, particularly for streams and small 

rivers. Recent research efforts by ORD to 

resolve technical issues such as determining 

stream classifi cation and setting reference 

conditions has been very helpful to the 

states, tribes, and territories. Direct technical 

assistance by OW, ORD, and OEI has been 

critical to achieving this progress. Substantial 

work remains to begin using bioassessment/

biocriteria in other water bodies.

Use of multiple types of animals and plants 

(assemblages) to assess water bodies has 

increased from 24 in 1989 to 26 in 1995 to 

45 in 2001!

Assessment of only one type of animal or plant life leads 

to only 80-85% effectiveness in identifying aquatic 

life use attainment or non-attainment. Assessment of 

a water body’s biology can include the analysis of 

macroinvertebrates (insects), periphyton (algae), or fi sh 

life. EPA recommends the use of two or more of these 

groups of biological assessments. 

Use of macroinvertebrates to assess water 

bodies has increased from 39 in 1989 to 44 

in 1995 to 56 in 2001!

Benthic macroinvertebrates are used in all but one 

bioassessment program (Hawaii is developing its 

assessment based on macroinvertebrates), but the use 

of fi sh and algae (periphyton) for evaluation purposes 

is increasing. Use of all types of organisms increased 

between 1995 and 2001 (see Figure 2).

Figure 2: Growth by Types of Assemblages Used for 

Bioassessment in Streams and Small Rivers.
BIOCRITERIA

Biocriteria are either narrative 

statements or numeric values that 

describe the biological condition of 

a water body necessary to protect 

an aquatic life use. Aquatic life uses 

are the goals for the protection and 

restoration of aquatic life. Designated 

uses for aquatic life can cover a range 

of biological conditions to both protect 

intact communities and establish 

restoration goals for compromised 

ecosystems. 

AQUATIC LIFE USE SUPPORT

Aquatic Life Use Support (ALUS) is a 

determination of the ability of a water body 

to support aquatic life. ALUS ratings are 

either fully supporting, partially supporting, 

or non-supporting of aquatic life. Water 

bodies that cannot fully support aquatic life 

are considered impaired and listed by the 

states and tribes on their 303(d) list. 

Figure 3: Growth in Programs Using 

Bioassessment to Determine Aquatic Life Use 

Attainment in Streams and Small Rivers.

2001 Narrative Biocriteria in WQS

Bioassessments and biocriteria 

give States a tool for directly 

determining the health of their 

aquatic life resources, for improving 

aquatic life designated uses, and 

for setting biocriteria to protect 

those uses. These narrative and/or 

numeric biocriteria may be formally 

adopted into water quality standards 

along with an anti-degradation policy 

intended to protect waters from further 

deterioration.

Use of bioassessment to determine 

Aquatic Life Use (ALU) attainment has 

increased from 31 States and Tribes in 

1995 to 40 States and Tribes in 2001
2001 Numeric Biocriteria in WQS

• A total of 29 national 

programs have incorporated 

Narrative Biocriteria 

into their Water Quality 

Standards in 2001.

Bioassessment can help states and tribes develop the 

targeted biological condition for a waterbody. Because 

chemical water quality standards alone may not ensure a 

healthy biological condition, most states are integrating 

biological information in their ALUS attainment 

determinations. 

In Idaho, for example, the designated aquatic life use of 

a waterbody is dependant upon its ability to support the 

actual or future use of the waterbody. Water bodies are 

• Five programs have incorporated 

 Numeric Biocriteria into their Water 

 Quality Standards in 2001

- Ten programs are now in the process of 

developing Numeric Biocriteria

Sixteen states are 

in the process of 

developing numeric or 

narrative biocriteria. 

The greatest 

increase in the use 

of narrative water 

quality standards took 

place between 1989 

and 1995. Numeric 

biocriteria has 

increased steadily.

- Of the 29 programs, 

22 have also developed 

quantitative implementation 

procedures or translators 

for their narrative criteria 

to use in their water quality 

management programs.

Maine has just completed 

development of numeric 

biocriteria in their water 

quality standards program. 

Numeric criteria were 

developed for dissolved 

oxygen and bacteria, and 

are designed to measure 

the response of benthic 

macroinvertebrates to 

human infl uences. Narrative 

criteria cover habitat and 

aquatic life in rivers 

and streams. Maine’s 

numeric biocriteria 

protocol provides a 

statistically defensible 

and reproducible 

decision-making tool 

for making quantitative 

determination about 

attainment of biological 

water quality standards.

evaluated to determine if the quality standards are being 

achieved and whether a healthy, balanced biological 

community is present. Aquatic Life Use designations are 

divided into two types; cold-water ALUs and warm-water 

ALUs. Three types of parameters are utilized to determine 

benefi cial use status: Aquatic Habitat Parameters, 

Biological Parameters, and Natural/Reference Conditions. 

ALUs are also utilized as part of the determination of 

TMDLs in Idaho. 
EXAMPLES OF PROGRESS 

Oregon has an extensive history in the use of 

biological data in water quality assessments. 

The program has grown since the early 1990’s. 

Oregon’s primary objectives are to identify 

trends in stream conditions and biological 

assemblages, identify the primary chemical 

and physical parameters impairing biological 

assemblages, assess the effectiveness of 

restoration projects and management activities 

designed to improve stream conditions, and help 

standardize protocols for biological assessments 

throughout the state and region.

The Oregon Department of Environmental Quality 

(DEQ) sets water quality standards to protect “benefi cial 

uses” such as recreation, fi sh habitat, drinking water 

supplies, and aesthetics. DEQ monitors water quality 

with regular sampling of more than 50 rivers and 

streams in the 18 designated river basins found in 

Oregon.

Multiple assemblages are used by Oregon to assess 

water bodies.

Narrative criteria were adopted in Oregon’s water 

quality standards and are applied using a numeric 

approach. 

The Oneida Nation has recently made 

great strides to implement a bioassessment 

program. In 1999, the Tribe began to 

sample macroinvertebrates and utilize their 

fi ndings. A formal biological monitoring 

program was established in 2000, including 

qualitative sampling and the development of 

standardized operating procedures. Future 

plans include sampling of invertebrates and 

fi sh. The Tribe has included biocriteria in its 

WQS.

Previous to initiation of its formal biological monitoring 

in 2000, the Tribe established an onsite aquatic 

invertebrate taxonomy laboratory. Best management 

practices have been tested and Standard Operating 

Procedures have been developed. 

The Tribe uses both macroinvertebrates and fi sh to assess 

its water bodies.

Bioassessment data is being used to assess the aquatic 

resources, determine the cause and effect of pollution, for 

monitoring, and for watershed based management. 

The Ohio River Valley Water Sanitation 

Commission (ORSANCO) is conducting biological 

monitoring of the Ohio River to develop techniques 

for large rivers in general and using biological 

monitoring assessment and criteria to characterize 

the Ohio River’s condition. The Commission is 

in the process of developing numeric biological 

criteria, and expanding its program into the 

tributaries and reaches of the Ohio River basin. 

ORSANCO collects data, develops methods, conducts 

sampling and develops assessment indices from the Ohio 

River for the eight states it represents. Their primary 

objective is to determine the extent to which the Ohio 

River will be capable of sustaining fi sh and other aquatic 

life.

Both macroinvertebrates and fi sh are used by ORSANCO 

to assess the Ohio River basin.

ORSANCO’s narrative biocriteria are supported by the 

numeric biocriteria that are being developed. 

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Printed on chlorine free 100% recycled paper with 

100% post-consumer fi ber using vegetable-based ink.

BIOASSESSMENT PROGRAM GOALS AND OBJECTIVES

EPA’s Offi ce of Water declared the following goals and objectives for the biocriteria program: 

EPA Offi ce of Water

Washington DC 20460

EPA-822-F-03-005

June 2003

Offi ce of Research and Development

Susan Cormier (513) 569-7995

Sue Norton (202) 564-3246

Steve Paulsen (541) 754-4428

Glenn Suter (513) 569-7808

Wayne Davis (410) 305-3030

Elizabeth Jackson (202) 566-0626

Offi ce of Water Offi ce of Environmental Information

 Offi ce of Science and Technology

Susan Jackson (202) 566-1112

William Swietlik (202) 566-1129

Treda Smith (202) 566-1128

Tom Gardner (202) 566-0386

Kellie Kubena (202) 566-0448

Chris Faulkner (202) 566-1185

Laura Gabanski (202) 566-1179

Doreen Vetter (202) 566-1379

Offi ce of Wetlands, Oceans, and Watersheds

Biocriteria/bioassessments will be used in ongoing 

regulatory programs.

Biocriteria/bioassessments will be used to assess the 

effectiveness of water quality management efforts.

Bioassessment data and biocriteria will be used to 

better communicate the health of the Nation’s waters.

All states/tribes will use bioassessments/biocriteria to 

evaluate the health of aquatic life in all water bodies.

Bioassessment data will be used by all states/tribes to 

better defi ne aquatic life uses.

Numeric biocriteria will be adopted in all state/tribal 

water quality standards to protect aquatic life uses.

Vermont has been conducting aquatic biological health 

assessments since the early 1970s. From 1985 to 

2001, approximately 1,500 stream assessments were 

completed using macroinvertebrates and/or fi sh from 

more than 900 wadeable stream reaches. Two Vermontspecifi c fi sh community Indexes of Biotic Integrity 

have been developed. Revisions in 2000 introduced 

the concept of reference-site conditions for assessment 

of biological condition. Vermont’s program utilizes a 

biocondition gradient to establish tiered aquatic life 

uses classifi cations. 

The Vermont Department of Environmental 

Conservation (VTDEC) collaborates with academic 

institutions, neighboring states, special groups, and 

volunteer monitors in their research.

Multiple assemblages are used by Vermont to assess 

its water bodies.

VTDEC uses narrative tiered biocriteria that is 

independent of the Water Quality standards. Numeric 

criteria are found within the VTDEC procedural 

documents.

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