Watershed Condition 

Classification 

Technical Guide

United States 

Department of 

Agriculture

Forest Service

FS-978

July 2011

“Ultimately, our success at the Forest Service will be measured 

in terms of watershed health on those 193 million acres of 

national forests and grasslands.”

Tom Tidwell

Chief, Forest Service

April 29, 2010

Primary Authors

John P. Potyondy

Program Manager and Hydrologist

Stream Systems Technology Center

Watershed, Fish, Wildlife, Air, and Rare Plants Staff

Washington Office

Theodore W. Geier

Regional Hydrologist

Eastern Region
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provider and employer.

Cover photo: Pisgah National Forest by Jack Holcomb.
Watershed Condition Classification Technical Guide iii

Contributors

Watershed Condition Advisory Team Members (October 2010)

John Potyondy	 Washington Office (WO), Watershed, Fish, Wildlife, Air and Rare Plants (WFWARP), Stream Systems

Technology Center

Ted Geier	 Eastern Region (R-9), Regional Office, Regional Hydrologist

Penny Luehring	 WO, WFWARP, Watershed Improvement Program Leader

Mark Hudy	 WO, WFWARP, Fish and Aquatic Ecology Unit (FAEU)

Brett Roper	 WO, WFWARP, FAEU

Ron Dunlap	 WO, WFWARP, Assistant Director, Watershed, Fish, and Air (retired)

Tom Doane	 Eastern Region (R-9), Deputy Director, Air, Water, Lands, Soils, Minerals and Environmental Engineering/

Services

Greg Kujawa 	 WO, Forest Management

Paul T. Anderson 	 WO, Engineering

Jaelith Hall-Rivera 	 WO, Fire and Aviation Management

Jim Keys WO, Ecosystem Management Coordination	

Michael Ielmini WO, Invasive Species Program

Ann Acheson 	 WO, WFWARP Air Program

Ray Thompson 	 WO, Program and Budget

Bob Davis	 Southwestern Region (R-3), Regional Director’s Representative

Sharon Friedman 	 Rocky Mountain Region (R-2), Strategic Planning Director

Karl Dalla Rosa 	 WO, State and Private Forestry (Forest Stewardship Program)

Thomas Brown 	 Rocky Mountain Research Station

Vacant WO, Rangeland Management	

Vacant	 WO, Environmental Sciences Research

Major Contributors to Indicator Rule Sets Development

Water Quality	 John Potyondy, Ted Geier, Cindy Huber

Water Quantity 	 John Potyondy, Ted Geier

Aquatic Habitat 	 Mark Hudy, Brett Roper, John Potyondy

Aquatic Biota 	 Mark Hudy, Brett Roper
iv Watershed Condition Classification Technical Guide

Riparian/Wetland Vegetation 	 Penny Luehring

Roads and Trails Paul T. Anderson

Soils	 Penny Luehring, Cindy Huber

Fire Regime or Wildfire	 Jaelith Hall-Rivera, Penny Luehring

Forest Cover Greg Kujawa

Rangeland Vegetation	 Charles Quimby

Terrestrial Invasive Species 	 Michael Ielmini

Forest Health Borys Tkacz, Cindy Huber
Watershed Condition Classification Technical Guide v

Introduction.............................................................................1

Objectives of This Guide ..........................................................1

Defining Watershed Condition .................................................2

Watershed Condition and Ecological Restoration ....................3

Watershed Condition Indicators...........................................4

The Watershed Condition Model ..........................................5

Types of Indicators ...................................................................7

Indicator Limitations and the Need for Professional

Judgment...................................................................................8

Providing for National Consistency and Local Flexibility .......8

Classifying Individual Indicators..............................................9

Regional and National Oversight ........................................11

Procedural Guidance...............................................................11

References..............................................................................13

Appendix. Rule Set for Watershed Condition 

Indicators and Attributes.....................................................14

Contents
vi Watershed Condition Classification Technical Guide
Watershed Condition Classification Technical Guide 1

The U.S. Department of Agriculture (USDA) Strategic Plan for

fiscal year (FY) 2010–2015 targets the restoration of watershed

and forest health as a core management objective of the national

forests and grasslands. To achieve this goal, the Forest Service,

an agency of USDA, is directed to restore degraded watersheds

by strategically focusing investments in watershed improvement

projects and conservation practices at landscape and watershed

scales.

In a 2006 review of the Forest Service Watershed Program,

the Office of Management and Budget (OMB) concluded that

the Forest Service lacks a nationally consistent approach to

prioritize watersheds for improvement (OMB 2006). The OMB

also noted that the current Forest Service direction in the Forest

Service Manual (FSM) 2521 for tracking watershed condition

class is vague, open to varied interpretation, and insufficient to

consistently evaluate watershed condition or track how condition changes over time. To address these issues, the Forest

Service formed the National Watershed Condition Team and

tasked it with developing a nationally consistent, science-based

approach to classify the condition of all National Forest System

(NFS) watersheds and to develop outcome-based performance

measures for watershed restoration. The team evaluated

alternative approaches for classifying watersheds (USDA

Forest Service 2007) and developed the watershed condition

classification (WCC) system described in this technical guide.

The team designed the WCC system to—

•	 Classify the condition of all NFS watersheds.

•	 Be quantitative to the extent feasible.

•	 Rely on Geographic Information System (GIS) technology.

•	 Be cost effective.

•	 Be implementable within existing budgets.

•	 Include resource areas and activities that have a significant

influence on watershed condition.

National forests are required to revise the classification on an

annual basis. We will use change in watershed condition class

as an outcome-based performance measure of progress toward

improving watershed condition on NFS lands. In order to

demonstrate improvement in condition class, we need to track

activities at the smallest feasible watershed unit, the 6th-level

hydrologic unit (typically 10,000 to 40,000 acres in size).

The WCC system is a national forest-based, reconnaissancelevel evaluation of watershed condition achievable within

existing budgets and staffing levels that can be aggregated for a

national assessment of watershed condition. The WCC system

offers a systematic, flexible means of classifying watersheds

based on a core set of national watershed condition indicators.

The system relies on professional judgment exercised by forest

interdisciplinary (ID) teams, GIS data, and national databases

to the extent they are available, and on written rule sets and

criteria for indicators that describe the three watershed condition classes (functioning properly, functioning at risk, and

impaired function). The WCC system relies on Washington

Office and regional office oversight for flexible and consistent

application among national forests. The WCC system is a first

approximation of watershed condition, and we will revise and

refine it over time. The expectation is that we will improve and

refine individual resource indicators and that we will develop

databases and map products to assist with future classifications.

The WCC information will be incorporated into the watershed

condition framework, which will ultimately be employed to

establish priorities, evaluate program performance, and communicate watershed restoration successes to interested stakeholders

and Congress.

Objectives of This Guide

The watershed condition goal of the Forest Service is “to protect

National Forest System watersheds by implementing practices

designed to maintain or improve watershed condition, which is

the foundation for sustaining ecosystems and the production of

renewable natural resources, values, and benefits” (FSM 2520).

U.S. Secretary of Agriculture Tom Vilsack reemphasized this

policy in his “Vision for the Forest Service” when he stated that

achieving restoration of watershed and forest health would be

the primary management objective of the Forest Service (USDA

2010). This Watershed Condition Classification Technical Guide

helps to implement this policy objective by—

1.	Establishing a systematic process for determining

watershed condition class that all national forests can apply

consistently.

2.	Improving Forest Service reporting and tracking of

watershed condition.

Introduction
2	 Watershed Condition Classification Technical Guide

3.	Strengthening the effectiveness of the Forest Service to maintain and restore the productivity and resilience of watersheds

and their associated aquatic systems on NFS lands.

Defining Watershed Condition

Watershed condition is the state of the physical and biological

characteristics and processes within a watershed that affect the

hydrologic and soil functions supporting aquatic ecosystems.

Watershed condition reflects a range of variability from natural

pristine (functioning properly) to degraded (severely altered

state or impaired). Watersheds that are functioning properly

have terrestrial, riparian, and aquatic ecosystems that capture,

store, and release water, sediment, wood, and nutrients within

their range of natural variability for these processes. When watersheds are functioning properly, they create and sustain functional terrestrial, riparian, aquatic, and wetland habitats that are

capable of supporting diverse populations of native aquatic- and

riparian-dependent species. In general, the greater the departure

from the natural pristine state, the more impaired the watershed

condition is likely to be. Watersheds that are functioning properly are commonly referred to as healthy watersheds.

Watersheds that are functioning properly have five important

characteristics (Williams et al. 1997):

1.	 They provide for high biotic integrity, which includes

habitats that support adaptive animal and plant communities

that reflect natural processes.

2.	 They are resilient and recover rapidly from natural and

human disturbances.

3.	 They exhibit a high degree of connectivity longitudinally

along the stream, laterally across the floodplain and valley

bottom, and vertically between surface and subsurface flows.

4.	 They provide important ecosystem services, such as highquality water, the recharge of streams and aquifers, the

maintenance of riparian communities, and the moderation of

climate variability and change.

5.	 They maintain long-term soil productivity.

Watershed condition classification is the process of describing

watershed condition in terms of discrete categories (or classes)

that reflect the level of watershed health or integrity. In our usage, we consider watershed health and integrity are conceptually

the same (Regier 1993): watersheds with high integrity are in

an unimpaired condition in which ecosystems show little or no

influence from human actions (Lackey 2001).

The FSM uses three classes to describe watershed condition

(USDA Forest Service 2004, FSM 2521.1).

1.	 Class 1 watersheds exhibit high geomorphic, hydrologic, and

biotic integrity relative to their natural potential condition.

2.	 Class 2 watersheds exhibit moderate geomorphic,

hydrologic, and biotic integrity relative to their natural

potential condition.

3.	 Class 3 watersheds exhibit low geomorphic, hydrologic, and

biotic integrity relative to their natural potential condition.

The FSM classification defines watershed condition in terms

of “geomorphic, hydrologic and biotic integrity” relative to

“potential natural condition.” In this context, integrity relates

directly to functionality. We define geomorphic functionality

or integrity in terms of attributes such as slope stability, soil

erosion, channel morphology, and other upslope, riparian, and

aquatic habitat characteristics. Hydrologic functionality or

integrity relates primarily to flow, sediment, and water-quality

attributes. Biological functionality or integrity is defined by

the characteristics that influence the diversity and abundance

of aquatic species, terrestrial vegetation, and soil productivity.

In each case, integrity is evaluated in the context of the natural

disturbance regime, geoclimatic setting, and other important

factors within the context of a watershed. The definition

encompasses both aquatic and terrestrial components because

water quality and aquatic habitat are inseparably related to the

integrity and, therefore, the functionality of upland and riparian

areas within a watershed.

Within this context, the three watershed condition classes are

directly related to the degree or level of watershed functionality

or integrity:

1.	 Class 1 = Functioning Properly.

2.	 Class 2 = Functioning at Risk.

3.	 Class 3 = Impaired Function.

In this guide, we characterize a watershed in good condition as

one that is functioning in a manner similar to natural wildland

conditions (Karr and Chu 1999, Lackey 2001). A watershed is

considered to be functioning properly if the physical attributes

are adequate to maintain or improve biological integrity. This

consideration implies that a Class 1 watershed that is functioning properly has minimal undesirable human impact on its

natural, physical, or biological processes, and it is resilient and

able to recover to the desired condition when disturbed by large

natural disturbances or land management activities (Yount and

Neimi 1990). By contrast, a Class 3 watershed has impaired
Watershed Condition Classification Technical Guide 3

function because some physical, hydrological, or biological

threshold has been exceeded. Substantial changes to the factors

that caused the degraded state are commonly needed to return

the watershed to a properly functioning condition.

Defining specific classes for watershed condition is subjective

and problematic for several reasons. First, watershed condition

is not directly observable (Suter 1993). In nature, no distinct

lines separate watersheds that are functioning properly from

impaired watersheds, and, therefore, every classification

scheme is arbitrary to some extent. Second, watershed condition is a mental construct that has numerous definitions and

interpretations in the scientific literature (Lackey 2001). Third,

the attributes that reflect the state of a watershed are continually changing because of natural disturbances (e.g., wildfire,

landslides, floods, insects, and disease), natural variability of

ecological processes (e.g., flows and cycles of energy, nutrients, and water), climate variability and change, and human

modifications.

Watershed Condition and Ecological 

Restoration

The most effective way to approach complex ecological issues

is to consider them at the watershed level, where the fundamental connection among all components of the landscape is

the network of streams that define the basin (Heller 2004, National Research Council 1999, Newbold 2002, Ogg and Keith

2002, Reid et al. 1996, Sedell et al. 2000, Smith et al. 2005,

Williams et al. 1997). Watersheds are also readily recognized

by local communities and resonate with much of the public as

a logical way to address resource management issues. Watersheds are easily identified on maps and on the ground, and their

boundaries do not change much over time (Reid et al. 1996).

Watersheds are integral parts of broader ecosystems, and

we can view and evaluate them at a variety of spatial scales.

Because watersheds are spatially located landscape features

that have been uniformly mapped for the entire United States at

multiple scales, they are ideal for tracking watershed improvement accomplishments both in terms of outputs (acres treated

on the ground) and outcomes (improvement in watershed

condition class). Reporting accomplishments and outcomes by

each watershed’s unique hydrologic unit code (HUC) avoids

double counting. The WCC system analyzes the effect of all

activities within a watershed; therefore, the system provides

an ideal mechanism for interpreting the cumulative effect over

time of a multitude of management actions on hydrologic and

soil function. Finally, many hydrologic and aquatic restoration

issues can be properly addressed only within the confines of

watershed boundaries. Watersheds provide a basis for developing restoration plans and priorities that can treat a multitude of

resource problems in a structured, comprehensive manner.

Many terrestrial ecological restoration issues, however, are

poorly addressed in a watershed context. Ecological restoration

issues dealing with vegetation and wildlife species composition,

structure, pattern, and diversity may not affect hydrologic and

soil functions and are best evaluated using ecological stratifications such as those depicted in the map, Bailey’s Ecoregions

and Subregions of the United States, Puerto Rico, and the U.S.

Virgin Islands (Bailey 1995). Consequently, we view watershed

condition, watershed health, and watershed restoration as a

subset of ecological condition, ecological health, and ecological

restoration.

In summary, ecological restoration focuses on the composition,

structure, pattern, and ecological processes necessary to make

terrestrial and aquatic ecosystems sustainable, resilient, and

healthy under current and future conditions. This includes

watershed condition and health. Watershed condition assessment places specific emphasis on the physical and biological

characteristics and processes affecting hydrologic and soil functions that support aquatic ecosystems. Therefore, in this WCC

system, primary emphasis is placed on indicators that directly

or indirectly affect soil and hydrologic functions and associated

riparian and aquatic ecosystems.
4	 Watershed Condition Classification Technical Guide

Watershed Condition Indicators

resource areas. Sound management or improving management

practices can often be as effective as implementing restoration

projects and must not be overlooked. To demonstrate improvement in condition class, we will need to track activities at the

smallest feasible watershed unit, the 6th-level HUC (typically,

10,000 to 40,000 acres).1

The WCC system consists of 12 watershed condition indicators:

1.	 Water Quality

2.	 Water Quantity

3.	 Aquatic Habitat

4.	 Aquatic Biota

5.	 Riparian/Wetland Vegetation

6.	 Roads and Trails

7.	 Soils

8.	 Fire Regime or Wildfire

9.	 Forest Cover

10.	 Rangeland Vegetation

11.	 Terrestrial Invasive Species

12.	 Forest Health

The WCC system described in this technical guide uses

12 indicators composed of attributes related to watershed

processes. The indicators and their attributes are surrogate

variables representing the underlying ecological functions and

processes that affect soil and hydrologic function. For most

of the indicators, the Forest Service can take direct action, or

cause others to take action, which contributes to maintaining

or improving watershed condition. This structure provides for

a direct linkage between the classification system and management or improvement activities the Forest Service conducts on

the ground. Because of this linkage, when a sufficient number

of properly designed and implemented restoration and/or

management actions occur within a watershed, we can express

the outcome as a change in condition class and use the resulting change in condition class for performance accountability

purposes. Management activities that affect the watershed

condition class are not limited to soil and water improvement

activities; they include a broad array of resource program

areas: hazardous fuel treatments, invasive species eradication, abandoned mine restoration, riparian area treatments,

aquatic organism passage improvement, road maintenance and

obliteration, and others. To change a watershed condition class

will, in most cases, require changes within a watershed that are

significant in their scope and include treatments from multiple

1 In the context of this classification system, we use the terms “watershed” and “hydrologic unit” synonymously. Hydrologic units, however, are truly only

synonymous with the classic watershed definition when their boundaries include all the source areas contributing surface water to a single, defined outlet

point. For the intended uses of this reconnaisance-level assessment, this distinction is relatively unimportant.
Watershed Condition Classification Technical Guide 5

The Watershed Condition Model

effects come from 20 percent of the causes. We also wanted

to be responsive to user input obtained during pilot testing on

national forests to keep the assessment compatible with the

subjective nature of many of the evaluations. We therefore

constrained the number of attributes and consequently the

amount of data that national forest ID teams will need to deal

with during the classification process.

We recognize from a scientific perspective that this watershed

conditions model with its many indicators will have problems

with autocorrelation. Because of the management need to show

linkages between activities on the ground and improvement in

watershed condition for performance accountability, however,

we chose to include a comprehensive suite of indicators that

represents the full scope of Forest Service management activities

and program areas. For example, road condition and stream

habitat condition may be highly correlated, however, eliminating stream habitat condition as an indicator would then preclude

having a feedback mechanism for taking credit for watershed

condition improvements derived from stream habitat improvement work. Using a comprehensive set of indicators favors

management performance tracking and accountability at the

expense of a more scientifically correct classification model.

The basic model used in this classification system provides

a forestwide, reconnaissance-level evaluation of watershed

condition. It offers a systematic, flexible means of classifying

and comparing watersheds based on a core set of national

watershed condition indicators. The indicators are grouped according to four major process categories: (1) aquatic physical,

(2) aquatic biological, (3) terrestrial physical, and (4) terrestrial

biological (fig.1). These categories represent terrestrial, riparian, and aquatic ecosystem processes or mechanisms by which

management actions can affect the condition of watersheds and

associated resources.

We will use a simple score card approach to assess watershed

condition class. Each of the four process categories is represented by a set of indicators (fig. 2, table 1). Each indicator is

evaluated using a defined set of attributes. For example, the

Aquatic Physical Processes category contains an indicator for

Aquatic Habitat Condition. Aquatic habitat condition is evaluated using three attributes: (1) habitat fragmentation, (2) large

woody debris, and (3) channel shape and function. Indicators

can have as few as one attribute or as many as four attributes.

We designed the classification to be as simple as possible based

on the “80/20 Rule,” which states that often 80 percent of

Watershed Condition Class

Aquatic

Physical

Processes

Aquatic

Biological

Processes

Terrestrial

Physical

Processes

Terrestrial

Biological

Processes

Figure 1.—The basic watershed condition model.
6	 Watershed Condition Classification Technical Guide

Watershed Condition Indicators

(12-Indicator Model)

Aquatic

Physical

(Weight = 30%)

1. Water Quality

1. Impaired waters 

(303(d) listed)

2. Water quality 

problems (not 

listed)

3. Aquatic Habitat

1. Habitat 

fragmentation

2. Large woody debris

3. Channel shape and 

function

2. Water Quantity

1. Flow characteristics

5. Riparian/Wetland 

Vegetation

1. Vegetation 

condition

4. Aquatic Biota

1. Life form presence

2. Native species

3. Exotic and/or 

aquatic invasive 

species

6. Roads and Trails

1. Open road density

2. Road and trail 

maintenance

3. Proximity to water

4. Mass wasting

8. Fire Regime or 

Wildfire

1. Fire Regime 

Condition Class

or

2. Wildfire Effects

7. Soils

1. Soil productivity

2. Soil erosion

3. Soil contamination

9. Forest Cover

1. Loss of forest

cover

10. Rangeland 

 Vegetation

 1. Rangeland vegetation condition

11. Terrestrial

 Invasive Species

 1. Extent and rate 

 of spread

12. Forest Health

 1. Insects and 

 disease

 2. Ozone

Aquatic

Biological

(Weight = 30%)

Terrestrial

Physical

(Weight = 30%)

Terrestrial

Biological

(Weight = 10%)

Figure 2.—Core national watershed condition indicators.
Watershed Condition Classification Technical Guide 7

Types of Indicators

We define indicators as simple quantifiable or qualitatively

determined measures of the condition and dynamics of

broader, more complex attributes of ecosystem health. We use

indicators because complex ecosystem attributes are difficult,

inconvenient, or too expensive to measure. Indicators act as

surrogates, representing the underlying ecological processes

that maintain watershed functionality and condition. The basic

watershed condition uses indicators that represent existing,

on-the-ground alterations of watershed conditions. We will

refine the indicators over time as better data and analysis tools

become available.

The indicators include three basic types of attributes:

1. Numeric attributes have associated numeric values (e.g.,

road density <1 mile/mile2

). Quantitative attributes are

simple to use but they need to be properly interpreted and

appropriate for the geographical setting of the watershed.

2. Descriptive attributes are qualitative variables subject to

some degree of interpretation by users (e.g., “Native mid

to late seral vegetation appropriate to the sites potential

dominates the plant communities and is vigorous, healthy,

and diverse in age, structure, cover, and composition on

more than 80 percent of the riparian and wetland areas in the

watershed.”). These semiquantitative attributes are typically

used when reliable numeric indicators or thresholds are

lacking or where quantitative data is either unavailable or too

expensive to obtain for entire watersheds.

3. Map-derived attributes are produced by teams of experts

that synthesize extensive data to create interpreted map

products (e.g., Fire Regime Condition Classes). Map products

Table 1.—Description of the 12 national core watershed condition indicators. (See the appendix for the complete rule set.)

Aquatic Physical Indicators

1. Water Quality This indicator addresses the expressed alteration of physical, chemical, and biological components of

water quality.

2. Water Quantity This indicator addresses changes to the natural flow regime with respect to the magnitude, duration, or

timing of the natural streamflow hydrograph.

3. Aquatic Habitat This indicator addresses aquatic habitat condition with respect to habitat fragmentation, large woody

debris, and channel shape and function.

Aquatic Biological Indicators 

4. Aquatic Biota This indicator addresses the distribution, structure, and density of native and introduced aquatic fauna.

5. Riparian/Wetland Vegetation This indicator addresses the function and condition of riparian vegetation along streams, water bodies, and

wetlands.

Terrestrial Physical Indicators 

6. Roads and Trails This indicator addresses changes to the hydrologic and sediment regimes because of the density, location,

distribution, and maintenance of the road and trail network.

7. Soils This indicator addresses alteration to natural soil condition, including productivity, erosion, and chemical

contamination.

Terrestrial Biological Indicators

8. Fire Regime or Wildfire This indicator addresses the potential for altered hydrologic and sediment regimes because of departures

from historical ranges of variability in vegetation, fuel composition, fire frequency, fire severity, and fire

pattern.

9. Forest Cover This indicator addresses the potential for altered hydrologic and sediment regimes because of the loss of

forest cover on forest lands.

10. Rangeland Vegetation This indicator addresses effects on soil and water because of the vegetative health of rangelands.

11. Terrestrial Invasive Species This indicator addresses potential effects on soil, vegetation, and water resources because of terrestrial

invasive species (including vertebrates, invertebrates, and plants).

12. Forest Health This indicator addresses forest mortality effects on hydrologic and soil function because of major invasive

and native forest insect and disease outbreaks and air pollution.
8	 Watershed Condition Classification Technical Guide

are generally high quality and objective if applied at the

appropriate scale.

We anticipate that map-based and numeric indicators will eventually replace other indicators as better data become available.

Indicator Limitations and the Need for 

Professional Judgment

Good indicator sets should be comprehensive, accurately reflect

watershed functionality, be readily measurable, be repeatable,

provide data that we can unambiguously interpret, convey an

understanding of how the ecosystem functions, and provide

insight into the cause-and-effect relationships between environmental stressors and the response of the ecosystem (Mulder

et al. 1999). Indicator sets, however, rarely exhibit all of these

characteristics. Our application of indicators in this guide

does not provide the level of detail expected from site-specific

watershed analysis or assessments (USDA/USDI 1998), nor is

it intended as a comprehensive evaluation of ecological conditions. Much like the Dow Jones Index gauges the strength of

the stock market, watershed condition indicators rapidly assess

the relative health of watersheds at a reconnaissance level. We

will need additional detailed assessments to validate conclusions, to identify specific watershed problems, and to arrive at

treatment solutions.

As simple surrogates for complex ecological processes, indicators do not necessarily represent cause-and-effect relationships.

Indicators are derived from studies that correlate the behavior

of indicators with environmental response variables of interest.

For example, increasing road density has been correlated

with increasing sediment yield in many studies nationwide.

However, the true set of environmental conditions that produce

sedimentation are complex, unmeasured, or unknown. Numerous other factors including soils, geology, slope, and road

condition also influence sediment yield. The result is that road

density is not a perfect predictor of the effects on sediment

yield. The quality of an indicator ultimately depends on the

quality of the research used to support it and its applicability

to different environmental settings, but no single indicator is a

perfect predictor of an environmental response.

Indicators work best when they are applied within the set of

conditions under which they were developed, and the same

indicator will have different interpretations in different ecological settings. For example, the naturally low volumes of large

woody debris in many streams of the arid Southwest would

represent degraded conditions in the forests of western Oregon.

Even the map-based indicators such as Fire Regime Condition

Class, which have been developed for the entire United States,

are subject to local professional validation and interpretation to

ensure that they are correctly applied. When used inappropriately, indicators and their attributes can provide misleading or

incorrect conclusions. Numeric values should not be thought of

as absolutes, but rather as diagnostic tools to promote discussion and understanding of relative watershed condition with

respect to the rule set. As a result, this process relies on local 

professional expertise and judgment to interpret the indicators and assess watershed condition.2

Providing for National Consistency 

and Local Flexibility

Professional judgment is needed to properly interpret the

indicators, but a certain level of consistency is needed to

compare watersheds at the national level. Achieving consistent

evaluation is a challenge when applying professional judgment across diverse ecosystems. To improve consistency, the

WCC system uses specific attributes along with quantitative

and qualitative rule sets to assess watershed condition. This

structured approach, coupled with appropriate regional office

oversight is designed to minimize bias among evaluators and

promote consistent interpretation of indicators.

Interpreting indicators, however, also requires local flexibility,

because only a few simple indicators have numeric ranges of

values that we can uniformly apply nationwide. For example,

the natural range of water temperatures will have different values in warm water streams compared with high elevation trout

streams, but an interpreted threshold specific to each environment indicates impairment. In addition, not all indicators apply

in all environmental conditions and geophysical settings. For

example, mass movement processes in the mountainous West

are virtually nonexistent in the Lake States of the Midwest.

To provide the needed flexibility, the WCC system allows

limited adjustment of core indicator attributes based on local

data and conditions. To help maintain consistency, regional or

national oversight teams need to approve these adjustments.

2 This process relies on intuitive conclusions and predictions that are dependent on an analyst’s training, interpretation of facts, information, and observations

and on his or her personal knowledge of the watershed being analyzed. Professional judgment in this context is excercised by a national forest’s interdisciplinary team.
Watershed Condition Classification Technical Guide 9

The goal of the process is to use the best available information

and data to assess watershed condition and to interpret the

range of watershed conditions in different physiographic settings in a correct and conceptually similar manner relative to

the range of proper and impaired functionality.

Forests may adjust attributes in one of three ways:

1. Modify the default values of an attribute. For example,

the default ranges in the basic model for road density may

be inappropriate for certain physiographic settings. Forests

may adjust the range and breaks between good, fair, and poor

ratings if they are supported by forest plans or local analysis

and data.

2. Substitute high-quality attribute data where appropriate.

For example, a forest may have extensive Properly Functioning Condition survey data that could be used to rate attributes

associated with the Riparian Vegetation Condition indicator.

Alternatively, the Alaska Region, may wish to substitute

riparian forest age class structure as their indicator of riparian vegetation condition.

3. Rate an attribute as Not Applicable. For example, a forest

lacking rangelands and grazing lands may exclude rangeland

vegetation from their assessment of the terrestrial physical

process category. A Not Applicable (N/A) rating can also

be used for indicators or attributes not relevant within a

particular geographical context. Only two indicators (Forest

Cover and Rangeland Vegetation) and two attributes (large

woody debris and mass wasting) may be rated N/A subject

to Regional Oversight Team approval.

Limited attribute adjustments provide the flexibility needed to

account for local differences in individual watersheds while

maintaining an acceptable level of regional and national

consistency. National consistency in scoring is maintained

by retaining a consistent set of indicators, averaging attribute

scores within each indicator, and weight-averaging indicator

scores by process category. National consistency is most

important at the process category level because each forest ID

team evaluates these fundamental ecosystem process categories

in a manner appropriate to their geographic setting.

We anticipate that there will be instances, or locally unique

circumstances, where the computed condition rating may

not accurately reflect true on-the-ground conditions. In these

cases, forests can exercise an “override option” and replace

the computed condition rating with the condition class judged

to be correct. Typically, the override option would be used to

designate severely impaired watersheds. Examples where the

override option might be appropriate include situations such

as (1) acid streams totally devoid of biological life, (2) water

quality impairment because of chemical contamination, or

(3) streams that are totally dewatered by diversions. In all of

these examples, the upland areas may be in excellent condition

but the water body is clearly impaired.

ID teams should use the override option judiciously and rarely.

Exercising the override option will require written documentation

and approval from the Regional Oversight Team. The National

Oversight Team will review use of the override option annually

to ensure that it is being applied in an appropriate manner.

Classifying Individual Indicators

Each indicator attribute receives a rating. The ratings are

expressions of the “best-fit” descriptor of the attribute for the

entire 6th-level watershed being classified. In the absence

of established numeric criteria for most of the attributes,

the boundaries between the attribute condition ratings were

assigned by resource specialists working on the Watershed

Condition Advisory Team using professional judgment guided

by the conceptual condition descriptions below.

Condition Rating 1 is synonymous with “GOOD” condition.

It is the expected indicator value in a watershed with high

geomorphic, hydrologic, and biotic integrity relative to natural

potential condition. The rating suggests that the watershed is

functioning properly with respect to that attribute.

Condition Rating 2 is synonymous with “FAIR” condition. It

is the expected indicator value in a watershed with moderate

geomorphic, hydrologic, and biotic integrity relative to natural

potential condition. The rating suggests that the watershed is

functioning at risk with respect to that attribute.

Condition Rating 3 is synonymous with “POOR” condition. It

is the expected indicator value in a watershed with low geomorphic,

hydrologic, and biotic integrity relative to natural potential

condition. The rating suggests that the watershed is impaired or

functioning at unacceptable risk with respect to that attribute.

To conceptualize this, the suggested approach is to identify the

upper and lower bounds for each indicator attribute to differentiate the desired conditions for that attribute (high integrity or high

functionality relative to site potential) compared with the unacceptable or impaired functionality of the attribute in absolute

terms. Conceptually, identifying the end points should be the

easiest task to accomplish in any rating scheme. The remaining
10 Watershed Condition Classification Technical Guide

middle designation is then identified by default and may contain a wide range of conditions. Ratings are scaled and evaluated in an absolute sense from functioning properly to impaired

function and not relative to a more limited range of attribute

conditions that may occur on a particular national forest.

The complete watershed condition rule set for indicators and

attributes is contained in the appendix. For each indicator, we

provide a brief statement of purpose, the rule set to use to determine the condition rating of each attribute, additional guidance

pertaining to rating the indicator attributes, definitions, a brief

rationale of how the indicator relates to watershed condition,

and references. Careful reading of the “Additional Guidance”

section for each indicator is essential for appropriate use of the

rule set.

The example below illustrates the process of scoring an individual indicator on Forest Service lands. The example indicator

is Roads and Trails Condition. The hypothetical watershed is

in the upper Midwest, which has no unstable landforms susceptible to mass wasting. The watershed is heavily roaded, with a

road density of 2.5 mi/mi2. Roads are well maintained but more

than 25 percent are within 100 feet of water. The forest ID team

decides that mass wasting is not an issue in this watershed and

assigned the following ratings to road condition:

3.	 The indicator scores within each ecosystem process category

are then averaged to arrive at a process category score.

4.	 The overall watershed condition score is computed as a

weighted3 average of the four process category scores.

5.	 The watershed condition scores are tracked to one decimal

point and reported as Watershed Condition Classes 1, 2, or 3.

Class 1 = scores of 1.0 to 1.6, Class 2 = scores from 1.7 to

2.2, and Class 3 = scores from 2.3 to 3.0.

6.	 A separate scoring process is conducted for Forest Service

and non-Forest Service lands within the watershed. We

will report results for Forest Service and non-Forest

Service lands and a watershed composite overall watershed

condition score (area weighted average of Forest Service and

non-Forest Service lands).

We will assign condition ratings to Forest Service ownerships,

private lands, and the composite watershed. The composite

score rates the whole watershed and includes FS and all other

ownerships, which are typically private land. The intent is to

differentiate watershed conditions attributable to Forest Service

management and problems that the FS can solve from those that

are associated with others. We also wish to support the Secretary’s call for an “all lands” approach to resource management.

Because we frequently lack data about the condition of nonForest Service lands, a simpler approach is applied to these

ownerships. We will assign non-Forest Service lands a subjective rating on a whole-watershed basis (i.e., we will not score

individual indicators and attributes). Non-Forest Service lands

will be rated as either THE SAME AS, BETTER THAN, or

POORER THAN Forest Service lands in the watershed. If

SAME AS is selected, we will assign the non-Forest Service

lands the same numeric condition score as Forest Service lands.

If non-Forest Service lands are not the same as Forest Service

lands, we will designate the non-Forest Service lands as simply

Class 1, Class 2, or Class 3 based on the best available knowledge. Forests are encouraged to rate non-Forest Service lands

equal to Forest Service lands if the true condition is unknown.

Forests may work with partner groups to classify non-Forest

Service lands, if they wish.

National forests will complete the classification process using

the Watershed Classification and Assessment Tracking Tool

(WCATT), a Web-based application developed by the natural

resource manager program staff.

Roads and trails attributes Rating Explanation

Open road density 3 Poor (impaired function)

Road maintenance 2 Fair (functioning at risk)

Proximity to water 3 Poor (impaired function)

Mass wasting N/A N/A (the watershed is

not susceptible to

mass wasting)

Indicator rating 2.7 Poor (impaired function)

3 We weight process categories to reflect their relative contribution toward watershed condition from a national perspective. The aquatic physical and aquatic

biological categories are weighted at 30 percent each because of their direct impact to aquatic systems (endpoint indicators). The terrestrial physical category

is weighted at 30 percent because roads are typically one of the highest sources of impact to watershed condition. Terrestrial biological is weighted at 10

percent because these indicators have indirect impact to watershed condition.

The complete classification process for each watershed is

described below:

1.	 For each 6th-level HUC watershed, all attributes for each

of the 12 indicators are scored by the forest ID team as

1 (Good—Functioning Properly ), 2 (Fair—Functioning at

Risk), or 3 (Poor—Impaired Function) using written criteria

and rule sets and the best available data and professional

judgment.

2.	 The attribute scores for each indicator are summed and

averaged to produce an indicator score.
Watershed Condition Classification Technical Guide 11

Regional and National Oversight

This classification process relies on Washington Office and

regional office oversight to provide for flexibility and consistency in application among national forests. The Washington

Office technical oversight role will be the primary responsibility of the Watershed, Fish, Wildlife, Air, and Rare Plants program staff, who will be assisted by members of the Watershed

Condition Advisory Team because of the interdisciplinary

nature of the classification process. Advisory team members

will provide technical input, expertise, and advice regarding

the rule sets affecting their program areas.

The Washington Office will coordinate an annual meeting to

discuss technical classification issues and resolve disputes.

This will include, as a minimum, a review of the extent to

which regions permitted use of “Not Applicable” and the

“Override” options.

National oversight roles and responsibilities include—

1.	Managing the national change process for the classification

system.

2.	 Ensuring consistency of classification among the regions.

3.	 Providing and supporting development of national GIS data

products for use in classification.

4.	 Providing direction and resolving disputes between regions.

Regions will provide the first line of quality control and quality

assurance in the classification process. Regions are encouraged

to work collectively with their forests to discuss interpretations

of the rule-set wording to achieve as much consistency as

practicable among forest units. Regions may wish to develop

regional additional guidance supplements to this guide that

document local application, data sources, and interpretations.

The membership of Regional Office Oversight Teams is left to

the discretion of the regions.

Regional oversight roles and responsibilities include—

1.	 Ensuring consistency of classification among the forests in

the region.

2.	 Ensuring that forests use ID teams to perform classifications.

3.	 Approving use or modification to attribute default value,

substituting high-quality attribute data or alternative

wording for attributes, and the use of the “Not Applicable”

and “Override” options.

4.	 Coordinating classification with adjoining regions and

national forests.

5.	 Consulting with the Washington Office when significant

modifications are approved.

Procedural Guidance

We specifically designed this watershed classification approach as a rapid, coarse filter, office assessment process to be

completed by a forest ID team over a 2-week time period using

professional judgment relying on existing information, maps,

and GIS coverage.

Preparation Checklist

1.	 Identify the composition and leadership of the forest ID

team that will classify watershed condition. Consider

having someone from the forest land and resource planning

staff as the team leader. The team should include technical

specialists with expertise in the 12 condition indicator

program areas. Typically, a forest ID team will do the

classification, but forests may include district staffs.

Specialists with long tenure and familiarity with the forest

can prove especially valuable to the team because of the

breadth of experience they provide.

2.	 Designate a technical lead for each of the watershed

condition indicators. For example, a hydrologist might lead

water-quality and water-quantity assessments.

3.	 Have each specialist review the rule set and additional guidance for his or her indicator to help him or her understand

the types of data and information that are useful to rate the

attributes for that indicator.

4.	 Over a 1-week period, have each specialist assemble the

available information in preparation for the classification

process. The types of information will vary by discipline

and may include forest inventory and monitoring reports,

interpreted map products, or assessments done by others.

5.	 Arrange for support from forest GIS specialists who can

provide analysis support (e.g., road density, and road

proximity to water analysis) that summarizes data by 6thlevel HUCs. Obtain the most current national GIS data
12 Watershed Condition Classification Technical Guide

coverage that is relevant to the analysis such as 303(d)

impaired streams, Fire Regime Condition Class, and insect

and disease maps, as well as local GIS data such as roads

and trails, dams and diversions, active and abandoned mines,

forest cover, recent large fires, etc.

6.	 Have each technical specialist develop a preliminary rating

for his or her indicator for each 6th-level HUC that can be

brought forward to the ID team for discussion.

Classification Process Checklist

1.	 Allow at least 1 week (5 days) for the ID team to complete

the classification process.

2.	 Convene the ID team and discuss the rule set for classification with the intent of achieving a common understanding.

At this time, the team should also discuss and reach agreement on any indicators and/or attributes (forest cover, rangelands, mass wasting, large woody debris) that they may wish

to designate as “Not Applicable” to the particular forest, any

proposed changes to attribute thresholds (e.g., road density),

or substitution of alternative attribute wording for some indicators. Before the actual meeting, discuss and obtain approval from your Regional Oversight Team, if necessary.

3.	 Determine ratings using an interactive ID team process. Individual specialists may offer their preliminary classification

of an indicator rating score, but the team should pool its collective knowledge to arrive at the final rating. The process

will go slowly for the first few watersheds as individuals begin to gain a common understanding of the rating approach,

and it may take several hours to classify the first watershed.

Consider beginning with a watershed known to be in good

condition and then rate one known to be in poor condition to

help provide perspective on the range of existing conditions.

The process will speed up noticeably after several iterations.

4.	 Use Tom Brown’s national watershed risk-rating maps

(Brown and Froemke 2010) as the forest’s beginning point

for classifying watershed condition. The national rating

will provide perspective regarding the spatial distribution

of watershed condition and illustrate how the local forest

ratings fit within the context of national ratings. Remember

that Brown and Froemke’s work assesses risk and is based

on broad-scale 5th-level HUCs using nationally consistent

coarse-scale data that are not particularly applicable to forest

management activities so they may not match well with your

local conditions.

5.	 Use the Watershed Condition Classification Tool (WCATT)

to record ratings and capture notes. Display the WCATT

form on a large screen. A second large screen display may

be useful to display other relevant GIS data layers.

Annual and Periodic Reassessments

1.	 Forests will need to update watershed condition classifications

each year to track changes in watershed condition class for

performance accountability. Concentrate on reassessing

those watersheds that are known or suspected to have changed

significantly from the previous year, focusing on—

a.	 Priority watersheds where improvement activities

have been implemented.

b.	 Watersheds that have experienced large fires since the

previous year.

c.	 Watersheds that have experienced extensive natural

disturbance. To facilitate annual updates, the WCATT

has been designed to roll forward the previous year’s

classification data into the current year and forests will

need to modify only those watersheds that have changed.

2.	 Conduct a more rigorous classification of all watersheds

every 5 years, or sooner if conditions warrant. In all cases,

use an ID team to perform annual and periodic reassessments.
Watershed Condition Classification Technical Guide 13

References

Bailey, R.G. 1995. Description of the ecoregions of the United

States. 2nd ed., rev. Misc. Pub. No. 1391.Washington, DC:

U.S. Department of Agriculture, Forest Service. 77 p.

http://www.fs.fed.us/land/ecosysmgmt/ecoreg1_home.html.

(24 March 2011).

Brown, T.C.; Froemke, P. 2010. Risk of impaired condition of

watersheds containing national forest lands. Gen. Tech. Rep.

RMRS-GTR-251. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 57 p.

Heller, D. 2004. A paradigm shift in watershed restoration.

Forum for Research and Extension in Natural Resources

(FORREX), Streamline Watershed Management Bulletin.

8(1): 21–23. http://www.forrex.org/streamline/ISS28/

streamline_vol8_no1_art7.pdf. (25 March 2011).

Karr, J.R.; Chu, L.W. 1999. Restoring life in running rivers:

better biological monitoring. Washington, DC: Island Press.

206 p.

Lackey, R.T. 2001. Values, policy, and ecosystem health.

Bioscience. 51: 437–443.

Mulder, B.; Noon, B.R.; Spies, T.A., et al. 1999. The strategy

and design of the effectiveness monitoring program for the

Northwest Forest Plan. Gen. Tech. Rep. PNW-GTR-437.

Washington, DC: U.S. Department of Agriculture, Forest

Service.

National Research Council. 1999. New strategies for America’s

watersheds. Committee on Watershed Management. Washington, DC: National Academy Press. 328 p.

Newbold, S.C. 2002. Integrated modeling for watershed management: multiple objectives and spatial effects. Journal of the

American Water Resources Association. 38(2): 341–353.

Ogg, C.W.; Keith, G.A. 2002. New Federal support for priority

watershed management needs. Journal of the American Water

Resources Association. 38(2): 577–586.

Regier, H.A. 1993. The notion of natural and cultural integrity.

In: Woodley, S.J.; Kay, J.J.; Francis, G., eds. Ecological

integrity and the management of ecosystems. Delray Beach,

FL: St. Lucie Press: 3–18.

Reid, L.M.; Ziemer, R.R.; Furniss, M.J. 1996. Watershed analysis on Federal lands of the Pacific Northwest. Humboldt Interagency Watershed Analysis Center Workshop. McKinleyville,

CA. http://www.fs.fed.us/psw/rsl/projects/water/1WhatisWA.

htm. (23 August 2010).

Smith, R.D.; Klimas, C.V.; Kleiss, B.A. 2005. A watershed

assessment tool for evaluating ecological condition, proposed

impacts, and restoration potential at multiple scales. SWWRP

Tech. Notes Collection. ERDC TNSWWRP-05-3. Vicksburg,

MS: U.S. Army Engineer Research and Development Center.

Suter, G.W. 1993. Critique of ecosystem health concepts

and indexes. Environmental Toxicology and Chemistry.

12: 1533–1539.

U.S. Department of Agriculture (USDA). 2010. Strategic plan

FY 2010–2015. Washington, DC: U.S. Department of Agriculture. 50 p. http://www.ocfo.usda.gov/usdasp/sp2010/sp2010.

pdf. (4 August 2010).

U.S. Department of Agriculture (USDA). 2004. Watershed

protection and management. FSM 2520. Washington, DC: U.S.

Department of Agriculture, Forest Service. 44 p.

U.S. Department of Agriculture (USDA), Forest Service. 2007

(June 15). An evaluation of watershed condition approaches

potentially suitable for characterizing national watershed

condition. Watershed Condition Core Team. Washington, DC:

Watershed, Fish, Wildlife, Air, and Rare Plants Program. 22 p.

U.S. Department of Agriculture/U.S. Department of the Interior

(DOI). 1998. A framework for analyzing the hydrologic condition of watersheds. BLM Tech. Note 405. Washington, DC:

U.S. Department of Agriculture, Forest Service; U.S. Department of the Interior, Bureau of Land Management. 37 p.

U.S. Office of Management and Budget (OMB). 2006. Forest

Service watershed program assessment. Washington, DC: U.S.

Office of Management and Budget. http://www.whitehouse.

gov/omb/expectmore/summary/10003029.2006.html. (4 August

2010).

Williams, J.E.; Wood, C.A.; Dombeck, M.P., eds. 1997.

Watershed restoration: principles and practices. Bethesda, MD:

American Fisheries Society.

Yount, J.D.; Niemi, G.J. 1990. Recovery of lotic communities

and ecosystems from disturbance—a narrative case study.

Environmental Management. 14: 547–570.
14 Watershed Condition Classification Technical Guide

Appendix. Rule Set for Watershed Condition Indicators and 

Attributes

1. Water Quality Condition

Purpose

This indicator addresses the expressed alteration of physical, biological, or chemical impacts to water quality.

Condition Rating Rule Set

1. Water Quality 

Condition 

Indicator

Minimal to no impairment to beneficial

uses of the water bodies in the

watershed.

Minor impairment to beneficial uses of

the water bodies in the watershed.

Significant impairment to beneficial

uses of the water bodies in the

watershed.

Attributes Good (1) Functioning Properly Fair (2) Functioning at Risk Poor (3) Impaired Function

Impaired waters

(303(d) listed)

No State-listed impaired or threatened

water bodies.

Less than 10 percent of the stream

miles or lake area are listed on the

303(d) or 305(b) lists and are not

supporting beneficial uses.

More than 10 percent of the stream

miles or lake areas are water quality

limited and are not fully supporting

beneficial uses as identified by a

State water quality agency integrated

report (303(d) & 305(b)).

Water quality 

problems

(not listed)

The watershed has minor or no water

quality problems.

For example, no documented

evidence of excessive sediment,

nutrients, chemical pollution or other

water quality issues above natural

or background levels; no consumption advisories or contamination from

abandoned or active mines; little or

no evidence of acidification, toxicity,

or eutrophication because of atmospheric deposition (see “Additional

Guidance” related to mines and

atmospheric deposition).

The watershed has moderate water

quality problems.

For example, consumption advisories

in localized areas; minor contamination from active or abandoned mines;

localized incidence of accelerated

sediment, nutrients, chemicals, or

infrequent, documented incidents

of contamination of public drinking

water sources. Moderate evidence of

acidification, eutrophication, or toxicity because of atmospheric deposition

(see “Additional Guidance” elated to

mines and atmospheric deposition).

The watershed has extensive water

quality problems.

For example, consumption advisories over extended areas; excessive sediment, nutrients, chemicals;

extensive contamination from active

or abandoned mines; or frequent

incidents of contamination of public

drinking water sources. Strong evidence of acidification, eutrophication,

or toxicity because of atmospheric

deposition (see “Additional Guidance”

related to mines and atmospheric

deposition).

Additional Guidance

1.	Water quality should address both surface and ground water.

2.	 Consider the mainstream systems as indicative of the whole

drainage system water quality, (i.e., the composite representative of the condition of all the streams in the watershed).

3.	 Consider chronic water quality deterioration and short-term

effects in light of overall sustained effects to beneficial uses

(i.e., both could be irreversible or irretrievable, but are not

always so).

4.	 Consider monitoring and inventory information available

from internal and external sources.

5.	 Because State water quality agency integrated reports

(303(d) and 305(b)) are submitted only every 2 years, use

the latest and best available information about the status of

impaired waters.

6.	 Atmospheric deposition can affect watersheds by causing

acidification (sulfur and nitrogen), eutrophication (nitrogen),

or toxicity (mercury). We can use water chemistry or critical

loads to classify conditions. A number of sources of water
Watershed Condition Classification Technical Guide 15

chemistry data are available (EPA 2006, 2009) and have

been compiled into a national database (USDA Forest Service 2009). The most current guidance on using chemistry

and critical loads for classification is available at http://

www.fs.fed.us/air.

a.	 For areas where acidification is the major concern,

use the following guidance for classification:

i.	 Condition Rating 1. All water sample sites from

the most sensitive water body in the watershed (or

a nearby watershed with similar lithology) show

an acid neutralizing capacity (ANC) of 50 microequivalents per liter (ueq/L) or greater.

ii.	 Condition Rating 2. One or more water sample sites

from the most sensitive water body in the watershed

(or a nearby watershed with similar lithology) show

an ANC of greater than 20 ueq/L and less than 50

ueq/L.

iii.	 Condition Rating 3. One or more water sample sites

from the most sensitive water body in the watershed

(or a nearby watershed with similar lithology) show

an ANC of 20 ueq/L or less.

iv.	 Water bodies that are naturally acidic (DOC > 5 mg/L)

or low in buffering capacity because of the influence

of wetlands or local geology should be assigned

Condition Rating 1.

v.	 Where ANC data is lacking, consider rating the

attribute using national deposition maps and lithology to find similar watersheds where ANC data is

available.

b.	 In areas where eutrophication (nitrogen) is the

primary problem, appropriate classification thresholds set by the U.S. Environmental Protection Agency

(EPA) (2010) for each region can be found at www.

fs.fed.us/air.

c.	 Where aquatic critical loads for sulfur or nitrogen

are available (such as Sullivan et al. 2007), compare

current deposition with the critical load and classify

as follows:

i.	 Condition Rating 1. Sulfur and/or nitrogen deposition is more than 10 percent below the aquatic

critical load.

ii.	 Condition Rating 2. Deposition is 0–10 percent

below the aquatic critical load.

iii.	 Condition Rating 3. Deposition is above the aquatic

critical load.

d.	 For rating water quality effects from abandoned and

active mines, use the following guidance for classification:

i.	 Condition Rating 1. Abandoned and active mines

with no associated evidence of water quality

contamination.

ii.	 Condition Rating 2. Abandoned or active mines that

have documented evidence of some adverse effects

to surface or groundwater quality.

iii.	 Condition Rating 3. Abandoned or active mines

that have been determined to be adversely affecting

surface or groundwater as a result of water quality

sampling.

Definitions

abandoned mines. Facilities, equipment, material, and associated surface disturbance resulting from past mineral exploration

or development, for which there exists no current authorization

and no evidence of current owner/operator.

acid neutralizing capacity. A measure of a water body’s ability to buffer acid compounds, defined as the difference between

cations of strong bases and anions of strong acids.

aquatic organism consumption advisories. Advisories issued

by the EPA or by State natural resource or other agencies that

advise the public to limit or avoid consumption of certain fish,

shellfish, mussels, crayfish, or other aquatic organisms because

of pollution. These advisories inform the public that high

concentrations of chemical contaminants have been found in

local fish and aquatic species and include recommendations to

limit or avoid consuming certain fish and wildlife species from

specific water bodies.

critical load. The amount of deposition of an atmospheric pollutant below which no harmful ecological effects occur. We can

calculate critical loads for both acidity and nutrient nitrogen in

terrestrial and aquatic systems.

designated beneficial uses. The desirable uses that water

quality should support. Beneficial uses include drinking water

supply, primary contact recreation (such as swimming), and

aquatic life support. Each designated use has a unique set of

water quality requirements or criteria that must be met for the

use to be supported. A water body may have multiple beneficial
16 Watershed Condition Classification Technical Guide

uses. Designated beneficial uses are identified by each State

water quality management agency.

eutrophication. Increased growth of biota and a rate of

productivity that is accelerated over the rate that would have

occurred naturally.

impaired or threatened water body. Any water body that is

listed according to section 303(d) of the Clean Water Act. The

303(d) list is a comprehensive public record of all impaired or

threatened water bodies, regardless of the cause or source of

the impairment or threat. A water body is considered impaired

when it does not attain the water quality standards needed

to support its designated uses. Standards may be violated

because of an individual pollutant, multiple pollutants, thermal

pollution, or an unknown cause of impairment. A water body

is considered threatened if it currently attains water quality

standards, but is predicted to violate standards by the time the

next 303(d) list is submitted to EPA. This determination is

made by individual State water quality management agencies.

lithology. The gross physical character of a rock or rock

formation described in terms of its structure, color, mineral

composition, grain size, and arrangement of its component

parts; all those visible features that in the aggregate impart

individuality to a rock formation.

Rationale for Indicator

Nonpoint source pollution, defined as water pollution that

comes from many different sources in a watershed, is the leading remaining cause of water quality problems in the United

States. Polluted runoff from agriculture, silvicultural activities,

and atmospheric deposition are among the leading causes of

nonpoint source pollution problems (EPA 2007). Because

nonpoint source pollutants are primarily derived from runoff

generated from watershed surfaces, watershed condition and

water quality are closely linked. The effects of nonpoint source

pollutants on specific waters vary and may not always be fully

assessed. We do know, however, that these pollutants have

harmful effects on drinking water supplies, recreation, fisheries,

and wildlife. In a recent report by EPA (2005), 45 percent

of the water bodies assessed by State water quality agencies

were reported as impaired or not clean enough to support their

designated uses, such as fishing and swimming.

Indicator References

Sullivan, T.J.; Cosby, B.J.; Snyder, K.U., et al 2007. Modelbased assessment of the effects of acidic deposition on sensitive

watershed resources in the national forests of North Carolina,

Tennessee, and South Carolina. http://www.esenvironmental.

com/PDF/north_carolina_modeling.pdf. (24 March 2011).

U.S. Department of Agriculture (USDA), Forest Service. 2009.

NRIS Air Module. http://www.fs.fed.us/air/. (Forest Service

Intranet; accessible only by agency employees.)

U.S. Environmental Protection Agency (EPA). 2006. National

stream assessment, wadeable streams assessment: a collaborative survey of the Nation’s streams. EPA 841-B-06-002.

Washington, DC: EPA. http://water.epa.gov/type/rsl/monitoring/

streamsurvey/index.cfm. (24 March 2011).

U.S. Environmental Protection Agency (EPA). 2007 (October).

National water quality inventory: report to Congress. 2002 Reporting Cycle. Doc. No. EPA-841-R-07-001. Washington, DC:

EPA. http://www.epa.gov/owow/305b/2002report/report2002305b.pdf. (24 March 2011).

U.S. Environmental Protection Agency (EPA). 2010. National

lakes assessment: a collaborative survey of the Nation’s lakes.

EPA 841-R-09-001. Washington, DC: EPA, Office of Water

and Office of Research and Development. http://water.epa.gov/

type/lakes/lakessurvey_index.cfm. (24 March 2011).
Watershed Condition Classification Technical Guide 17

2. Water Quantity Condition

Purpose

This indicator addresses changes to the natural flow regime with respect to the magnitude, duration, or timing of natural streamflow

hydrographs.

Condition Rating Rule Set

2. Water 

Quantity 

Condition 

Indicator

Stream hydrographs have no or minor

departure from natural conditions.

Stream hydrographs have moderate

recognized departures from natural

conditions part of the year.

The magnitude, duration, and/or

timing of annual extreme flows (low

and/or high) significantly depart from

the natural hydrograph.

Attributes Good (1) Functioning Properly Fair (2) Functioning at Risk Poor (3) Impaired Function

Flow 

characteristics

The watershed lacks significant

man-made reservoirs, dams, or

diversion facilities. The watershed

has primarily free-flowing rivers and

streams, unmodified lakes, and no

or limited ground water withdrawals.

Stream hydrographs have no or minor

alterations from natural (unaltered by

anthropogenic actions) conditions.

The watershed contains dams and

diversion facilities that are operated to

partially mimic natural hydrographs.

A departure from a natural hydrograph occurs during periods other

than extreme flows (lows or highs).

Peaks and base flows are maintained

but changes to the timing, rate of

change, and/or duration of mid-range

discharges occur.

Dams and diversion facilities are

operated so that they fail to mimic

natural hydrographs. The magnitude,

duration, and/or timing of annual extreme flows (low or high) significantly

depart from the natural hydrograph.

The timing and the rate of change

in flows often do not correlate with

expected seasonal changes.

Additional Guidance

1.	Compare existing conditions with historic conditions and

reference conditions. The natural hydrograph baseline is

streamflows unaltered by anthropogenic actions. Emphasis is

on the permanent, long-term effects of water diversions and

water control features rather than on flow changes caused by

vegetation management.

2.	Consider both the mainstream and tributaries when evaluating changes to flow hydrology. In most cases, depending on

their extent and magnitude, cumulative changes observable

in the mainstream stream will reflect flow changes to

tributaries.

3.	Concentrate evaluation on effects to perennial, mainstream

streams rather than headwater tributaries or intermittent

flows, except in arid or semiarid regions where intermittent or interrupted flows are important components of the

hydrograph.

4.	The effect on water quantity condition should be significant

enough so that it results in measurable changes to the hydrograph. For example, water yield changes resulting from vegetation management would generally not be included unless

the change was extensive and prolonged (e.g., extensive

deforestation, urbanization, wildfire, dams, diversions,

disease, insects, or other disturbances that significantly and

persistently alter runoff).

5.	The extent of groundwater pumping would generally need to

be developed for large-scale industrial or large municipality

use to measurably influence streamflow. In general, household groundwater use for domestic purposes will not have

a significant influence on water quantity unless a watershed

was developed to such an extent that it was closed to additional well developments by State water resource authorities.

6.	Consider the effects of transbasin diversions with respect to

both the donor and receiving streams.

Definitions

natural hydrograph. A hydrograph representing the natural

seasonal flows of a river without the moderating influence of

human-created features (e.g., dams and canals) or management

actions.

Rationale for Indicator

Watershed condition has large role to play in the magnitude,

frequency, and timing of runoff from a watershed. The quantity

and timing of streamflow are critical components of water
18 Watershed Condition Classification Technical Guide

supply, water quality, and the ecological integrity of river

systems (Hill et al. 1991). The effects of human alteration on

the natural flow regimes of rivers and ecological processes are

now reasonably well understood (Poff et al. 1997). Modifying

natural hydrologic processes disrupts the dynamic equilibrium

between the movement of water and the movement of sediment

that exists in free-flowing rivers (Dunne and Leopold 1978).

This disruption alters physical habitat characteristics, including

water temperature, oxygen content, water chemistry, and

substrate composition, and adversely changes the composition, structure, or function of aquatic, riparian, and wetland

ecosystems (Bain et al. 1988). The result is that many rivers no

longer support socially valued native species or sustain healthy

ecosystems (NRC 1992).

Indicator References

Bain, M.B.; Finn, J.T.; Booke, H.E. 1988. Stream flow regulation and fish community structure. Ecology. 69: 382–392.

Dunne, T.; Leopold, L.B. 1978. Water in environmental planning. San Francisco: W.H. Freeman. 818 p.

Hill, M.T.; Platts, W.S.; Beschta, R.L. 1991. Ecological and

geomorphological concepts for instream and out-of-channel

flow requirements. Rivers. 2: 198–210.

National Research Council (NRC). 1992. Restoration of aquatic

systems: science, technology, and public policy. Washington,

DC: National Academy Press. 576 p.

Poff, N.L.; Allan, J.D.; Bain, M.B., et al. 1997. The natural

flow regime: a paradigm for river conservation and restoration.

BioScience. 47(11): 769–784.
Watershed Condition Classification Technical Guide 19

3. Aquatic Habitat Condition

Purpose

This indicator addresses aquatic habitat condition with respect to habitat fragmentation, large woody debris, and channel shape and

function.

Condition Rating Rule Set

3. Aquatic 

Habitat 

Condition 

Indicator

The watershed supports large

continuous blocks of high-quality

aquatic habitat and high-quality

stream channel conditions.

The watershed supports medium to

small blocks of contiguous habitat.

Some high-quality aquatic habitat

is available, but stream channel

conditions show signs of being

degraded.

The watershed supports small

amounts of continuous high-quality

aquatic habitat. Most stream channel

conditions show evidence of being

degraded by disturbance.

Attributes Good (1) Functioning Properly Fair (2) Functioning at Risk Poor (3) Impaired Function

Habitat 

fragmentation 

(including 

aquatic 

organism 

passage)

Habitat fragmentation is not a serious

concern (more than 95 percent of

historic aquatic habitats are still connected).

Aquatic habitat fragmentation is

increasing because of temperature,

aquatic organism passage blockages,

or dewatering (only 25 to 95 percent

of the historic aquatic habitats are still

connected).

Aquatic habitat fragmentation because of temperature, blockages, or

dewatering is a serious concern (less

than 25 percent of the historic aquatic

habitats still connected).

Large woody 

debris

In aquatic and riparian systems that

evolved with wood near the streams,

large woody debris is present and

continues to be recruited into the

system at near natural rates.

In aquatic and riparian systems that

evolved with wood, large woody

debris is present but is recruited into

the system at less than natural rates

because of riparian management

activities.

In a system that should contain large

wood as an ecosystem component,

wood is lacking resulting in poor

riparian or aquatic habitat conditions

including bank destabilization, inadequate pool formation, and microclimate maintenance.

Channel shape 

and function

Channel width-to-depth ratios exhibit

the range of conditions expected in

the absence of human influence. Less

than 5 percent of the stream channels

show signs of widening. Channels are

vertically stable, with isolated locations of aggradation or degradation,

which would be expected in nearnatural conditions. The distribution of

channels with floodplain connectivity

is close to that found in reference watersheds of similar size and geology.

Channel width-to-depth and vertical

stability are maintained except where

riparian vegetation has been disturbed. Between 5 and 25 percent of

the stream channel have seen an increase in width-to-depth ratios. Channel degradation and/or aggradation

are evident but limited to relatively

small sections of the channel network.

There is evidence of downcutting to

the extent that some stream channels are no longer connected to their

floodplain.

More than 25 percent of channels

have width-to-depth ratios greater

than expected under near-natural

conditions. The size and extent of

gullied sections of channels are

extensive, currently increasing,

or have increased recently. Many

streambanks show signs of active

erosion above that which is expected

naturally. Channel degradation and/

or aggradation are evident and widespread because of unstable streambeds and banks. Many (more than 50

percent) of the stream channels are

disconnected from their floodplain

or are braided channels because of

increased sediment loads.

Additional Guidance

1.	 If forest plan aquatic habitat direction exists for habitat

fragmentation, large wood, or channel shape and function,

use the local thresholds derived from forest plan standards

and guidelines to determine the appropriate rating for the

attributes.

2.	 The focus of this evaluations should be on fish bearing

channels lower in the watershed that are typically response

reaches (<3 percent gradient). Consider the length of these

reaches in the watershed, and estimate the length of channel

that meets the criteria for the class.

3.	 Large woody debris. Rate this attribute Not Applicable

(N/A) if the aquatic and riparian systems in the watershed
20 Watershed Condition Classification Technical Guide

evolved without wood and if the presence of wood is not an

important component of the aquatic ecosystem. The use of

N/A will likely be limited to western rangeland watersheds.

4.	 In aquatic habitats lacking aquatic biota and/or permanent

habitat (e.g., some Southwest desert streams), evaluate

conditions with respect to what you would expected to be

present under natural conditions, or absent human-induced

impacts.

Definitions

aquatic habitat fragmentation. Habitat fragmentation occurs

when a large region of habitat has been degraded or fragmented

into a collection of smaller patches of nonconnected habitat.

Major causes of aquatic habitat fragmentation are dams, diversions, mines, roads, inadequate culverts, and increased stream

temperatures that prevent fish from moving freely throughout

an aquatic system.

floodplain connectivity. In channels with existing or historic

floodplains, floodplain connectivity refers to the ability of

flows greater than bankfull to overflow on to the vegetated

floodplain without accelerated impact to streambanks. Floodplain connectivity may be lost through the construction of

levees, or through the downcutting of channels because of

improper road location and construction, overgrazing, storage

dams, or increased flow or sediment. Incised channels lack

floodplain connectivity.

response channel reaches. Low gradient (in general, less

than 3 percent) transport-limited channels in which significant

morphologic adjustment occurs in response to increased sediment supply as defined by Montgomery and Buffington (1993).

Response channels generally correspond to Rosgen C, D, E,

and F channel types (Rosgen 1996). Response reaches are

evaluated because they are the most susceptible to change from

disturbance.

Rationale for Indicator

Watersheds in good condition tend to retain most of their natural heterogeneity and complexity such as preserving the lateral,

longitudinal, and vertical connections between system components as well as the natural spatial and temporal variability of

these components (Naiman et al. 1992). Floodplain connectivity

demonstrates maintenance of the vertical component of stream

channels and provides for off-channel habitat among other

features. Habitat fragmentation evaluates the longitudinal component of healthy systems. Aquatic habitat fragmentation by

fish passage blockages, dewatering, or temperature increases,

along with simplification from activities including channelization, channel bed sedimentation, woody debris removal, and

flow regulation, results in loss of diversity within and among

native fish species (Lee et al. 1997). Maintaining heterogeneous

and complex aquatic organism habitat at multiple scales is

recognized as an important influence on species diversity and

ecosystem stability (Sedell et al. 1990).

Indicator References

Lee, D.C., et al. 1997. An assessment of ecosystem components

in the Interior Columbia Basin and portions of the Klamath

and Great Basin. Broadscale assessment of aquatic species and

habitats. Gen. Tech. Rep. PNW-GTR-405. Portland, OR: U.S.

Department of Agriculture, Forest Service. Vol. 3.

Montgomery, D.R.; Buffington, J.M. 1993. Channel classification, prediction of channel response, and assessment of channel

condition. Rep. TFW-SH10-93-002. Prepared for the SHAMW

Committee of Washington State Timber/Fish/Wildlife Agreement. Seattle, WA: University of Washington. 84 p.

Naiman, R.J.; Beechie, T.J.; Benda, L.E., et al. 1992. Fundamental elements of ecologically healthy watersheds in the

Pacific Northwest coastal ecoregion. In: Naiman, R.D., ed.

Watershed management: balancing sustainability and environmental change. New York: Springer-Verlag: 127–188.

Rosgen, D.L. 1996. Applied river morphology. Pagosa Springs,

CO: Wildland Hydrology. 390 p.

Sedell, J.R.; Reeves, G.H.; Hauer, F.R., et al. 1990. Role of

refugia in recovery from disturbances: modern fragmented and

disconnected river systems. Environmental Management. 14(5):

711–724.
Watershed Condition Classification Technical Guide 21

4. Aquatic Biota Condition

Purpose

This indicator addresses the distribution, structure, and density of native and introduced aquatic fauna.

Condition Rating Rule Set

4. Aquatic Biota 

Condition 

Indicator

All native aquatic communities and

life histories appropriate to the site

and watershed are present and selfmaintaining.

The watershed is a stronghold for one

or more native aquatic communities

when compared to other sub-basins

within the native range. Some life

histories may have been lost or

range has been reduced within the

watershed.

The watershed may support small,

wildly scattered populations of

native aquatic species. Exotic and/

or aquatic invasive species are

pervasive.

Attributes Good (1) Functioning Properly Fair (2) Functioning at Risk Poor (3) Impaired Function

Life form 

presence

More than 90 percent of expected

aquatic life forms and communities

are present based on the potential

natural communities present.

From 70 to 90 percent of expected

aquatic life forms and communities

are present based on the potential

natural communities present.

Less than 70 percent of expected

aquatic life forms and communities

are present based on the potential

natural communities present.

Native species Most native aquatic species and life

histories that would be expected

based on potential natural communities are present and self-maintaining.

Limited intermixing of native species

genetics with outside sources has occurred, which can happen when moving aquatic species from one aquatic

habitat to another.

Residual and, at times isolated, native endemic species that would be

expected based on potential natural

communities may be located in specific aquatic habitats. Some nonnative

species may be present but native

species are self-sustaining where

found.

Exotic and/or aquatic invasive species are present and have mostly replaced native aquatic species. Legacy

management effects to habitat from

chemicals, sediment or other pollution may limit the knowledge available

on endemic native species. Aquatic

habitat is disconnected by passage or

flow barriers.

Exotic and/or 

aquatic invasive 

species

Exotic and/or aquatic invasive species may be present but they have

not greatly altered condition of native

species (less than 25 percent of the

historic aquatic-life-bearing habitats

have exotic and/or aquatic invasive

species present, spread of exotics

and/or aquatic invasive species have

been minimal over the past decade).

Exotic and/or aquatic invasive species are generally present and have

lowered the health and sustainability

of native species (between 25 and 50

percent of the historic native aquaticlife-bearing habitats have exotic and/

or aquatic invasive species present

and/or there has been an expansion

of exotic and/or aquatic invasive species over the past decade).

Exotic and/or aquatic invasive species are present and have greatly lowered the condition of native aquatic

species (more than 50 percent of the

historic native-fish-bearing streams

have exotic and/or aquatic invasive

species present and/or there has

been an expansion of nonnative exotic and/or aquatic invasive species

over the past decade.

Additional Guidance

1.	 Life form presence. Avoid focus on single species; focus on

communities.

2.	 Exotic and/or aquatic invasive species. The presence of exotic and/or aquatic invasive species or communities is used

as an indicator of altered or impaired conditions. Although

exotic and/or aquatic invasive species can significantly affect native aquatic faunal integrity, intraspecies interactions

are not considered for this assessment. For this assessment,

the widespread presence of exotic and/or aquatic invasive

species indicates poor conditions. For example, if you note

the presence of bluegill in an area that historically supported

native rainbow trout, and you find in your records that water

temperatures and flow conditions are now favoring bluegill

and are not providing suitable habitat conditions for trout,

your conclusion is that the habitat is in poor condition and

the presence of bluegill is an indicator of this condition.

Definitions

aquatic invasive. Nonnative species that are also considered

invasive.

exotic species. Nonnative species that are not considered

invasive.

native fauna. Any faunal species native to a watershed.
22 Watershed Condition Classification Technical Guide

Rationale for Indicator

Native fish and other native aquatic biota have been adversely

affected by land and watershed development, habitat loss,

direct human harvest, and increased competition from

introduced exotic and/or aquatic invasive species. Introduced

species and stocks are major threats to native fishes and

aquatic biota by way of predation, competition, introduction of

diseases and parasites for which native species lack resistance,

environmental modification, inhibition of reproduction, and

hybridization (Moyle et al. 1986, Nehlsen et al. 1991). Nonnative introductions of species frequently have effects that

cascade through entire ecosystems and compromise ecological

structure and function in unforeseen ways (Winter and Hughes

1995). Although introductions have increased fishing opportunities, the ecological consequences have been high and the

dramatic expansion of nonnative species has left many systems

compromised (Angermeier and Karr 1994).

Indicator References

Angermeier, P.L.; Karr, J.R. 1994. Biological integrity versus

biological diversity as policy directives: protecting biotic

resources. BioScience. 44(10): 690–697.

Moyle, P.B.; Li, H.W.; Barton, B.A. 1986. The Frankenstein

effect: impact of introduced fishes on native fishes in North

America. In: Stroud, R.H., ed. Fish culture in fisheries management. Bethesda, MD: American Fisheries Society: 415–426.

Nehlsen, W.; Williams, J.E.; Lichatowich, J.A. 1991. Pacific

salmon at the crossroads: stocks at risk from California,

Oregon, Idaho, and Washington. Fisheries. 16: 4–21.

Winter, B.D.; Hughes, R.M. 1995. AFS draft position on

biodiversity. Fisheries. 20(4): 20–25.
Watershed Condition Classification Technical Guide 23

5. Riparian/Wetland Vegetation Condition

Purpose

This indicator addresses the function and condition of native riparian vegetation along streams, water bodies, and wetlands.

Condition Rating Rule Set

5. Riparian/

Wetland 

Vegetation 

Condition 

Indicator

Native vegetation is functioning

properly throughout the stream

corridor or along wetlands and water

bodies.

Disturbance partially compromises

the properly functioning condition of

native vegetation attributes in stream

corridor areas or along wetlands and

water bodies.

A large percent of native vegetation

attributes along stream corridors,

wetlands, and water bodies is not

functioning properly.

Attributes Good (1) Functioning Properly Fair (2) Functioning at Risk Poor (3) Impaired Function

Vegetation 

condition

Native mid to late seral vegetation

appropriate to the site’s potential

dominates the plant communities

and is vigorous, healthy, and diverse

in age, structure, cover, and composition on more than 80 percent

of the riparian/wetland areas in the

watershed. Sufficient reproduction of

native species appropriate to the site

is occurring to ensure sustainability.

Mesic herbaceous plant communities

occupy most of their site potential.

Vegetation is in a dynamic equilibrium

appropriate to the stream or wetland

system.

Native vegetation demonstrates a

moderate loss of vigor, reproduction, and growth, or it changes in

composition, especially in areas most

susceptible to human impact. Areas

displaying light to moderate impact to

structure, reproduction, composition,

and cover may occupy 25 to 80 percent of the overall riparian area with

only a few areas displaying significant

impacts. Up to 25 percent of the

species cover or composition occurs

from early seral species and/or there

exist some localized but relatively

small areas where early seral vegetation dominates, but the communities

across the watershed are still dominated by mid to late seral vegetation.

Xeric herbaceous communities exist

where water relationships have been

altered but they are relatively small

and localized, generally are not continuous across large areas, and do not

dominate across the watershed.

Native vegetation is vigorous, healthy,

and diverse in age, structure, cover,

and composition on less than 25

percent of the riparian/wetland areas

in the watershed. Native vegetation demonstrates a noticeable loss

of vigor, reproduction, growth, and

changes in composition as compared

with the site’s potential communities

throughout areas most susceptible to

human impact. In these areas, cover

and composition are strongly reflective of early seral species dominance

although late- and mid-seral species

will be present, especially in pockets.

Mesic-dependent herbaceous vegetation is limited in extent with many

lower terraces dominated by xeric

species most commonly associated

with uplands. Reproduction of mid

and late seral species is very limited.

For much of the area, the water table

is disconnected from the riparian area

and the vegetation reflects this loss of

available soil water.

Additional Guidance

1.	 Use the following riparian/wetland vegetation attribute questions to help you evaluate the existing condition of riparian/

wetland vegetation in the watershed (Prichard et al. 1988).

In all cases, evaluate the site relative to the site’s potential

natural vegetation:

a.	 Is there a diverse age-class distribution of native

riparian/wetland vegetation (recruitment for maintenance and recovery)?

b.	 Is there a diverse composition of native riparian/

wetland vegetation (for maintenance and recovery)?

c.	 Are native species present that indicate maintenance

of riparian/wetland soil moisture characteristics and

connectivity between the riparian/wetland vegetation and the water table typical of riparian/wetland

systems in the area?

d.	 Is streambank native vegetation composed of those

plants or plant communities that have root masses

capable of withstanding high streamflow events?

e.	 Does native riparian/wetland vegetative adequately

cover and protect banks and dissipate energy during

high flows?

f.	 Do native riparian/wetland plants exhibit high vigor?
24 Watershed Condition Classification Technical Guide

g.	 Are native plant communities an adequate source of

coarse and/or large woody material (for maintenance

and recovery)?

2.	 If forest plan riparian management direction exists for

riparian/wetland vegetation, use the local thresholds derived

from forest plan standards and guidelines to determine the

appropriate rating for this attribute. For example, riparian timber stand conditions may be appropriate in some

ecosystems as a measure of riparian vegetation condition

but riparian/wetland herbaceous vegetation conditions are

appropriate for other systems.

3.	Where the Bureau of Land Management’s Proper Functioning Condition assessments have been completed (Prichard

et al. 1994), rate the properly functioning condition category

as Condition Class 1, the functional at risk category as Condition Class 2, and the nonfunctional category as Condition

Class 3 based on the percent of riparian areas in each

category.

Definitions

functional at risk (functioning at risk). Riparian/wetland

areas that are in functional condition, but one or more existing

soil, water, or vegetation attributes makes them susceptible to

degradation.

functioning properly. Riparian/wetland health (functioning

condition), an important component of watershed condition,

refers to the ecological status of vegetation, geomorphic, and

hydrologic development, along with the degree of structural

integrity exhibited by the riparian/wetland area. Riparian/

wetland areas that are functioning properly exist when adequate

vegetation, landform, or large woody debris is present to dissipate stream energy associated with high waterflow, thereby

reducing erosion and improving water quality; filter sediment,

capture bedload, and aid floodplain development; improve

flood-water retention and ground-water recharge; develop

root masses that stabilize streambanks against cutting action;

develop diverse ponding and channel characteristics to provide

the habitat and the water depth, duration, and temperature

necessary for fish production, waterfowl breeding, and other

uses; and support greater biodiversity.

nonfunctional (impaired). Riparian/wetland areas that clearly

are not providing adequate vegetation, landform, or large

woody debris to dissipate stream energy associated with high

flows, and thus are not reducing erosion, improving water

quality, etc.

riparian zone, riparian area, stream corridor. The interface

between land and the banks of a stream, river, or other body of

water. We use the term riparian in its broadest sense to include

areas adjacent to a stream, river, or lake, recognizing that a

diverse mixture of different definitions exists across the United

States. Plant communities along these water margins are called

riparian vegetation and are characterized by hydrophytic plants.

wetlands. Those areas that are inundated or saturated by

surface or ground water at a frequency and duration sufficient

to support, and that under normal circumstances do support, a

prevalence of vegetation typically adapted for life in saturated

soil conditions. In general, wetlands include swamps, marshes,

bogs, and similar areas.

Rationale for Indicator

Riparian and wetland areas are the interface between terrestrial and aquatic ecosystems and are an integral part of the

watersheds. Consequently, the health of these areas is closely

interrelated to the condition of the surrounding watershed

(Debano and Schmidt 1989, Hornbeck and Kochenderfer 2000).

The health of riparian corridors is dependent on the storage

and movement of sediment through the channel system and

also on the movement of sediment and water from surrounding

hillslopes into the channel system. Human-induced and natural

disturbances can alter these processes either indirectly to the

watershed or directly to riparian areas themselves by livestock

grazing, road construction, mining, irrigation diversion, channel

modification, flooding, wildfire, and similar disturbances (Baker

et al. 2004, NRC 2002). One good measure of riparian/wetland

health is the ecological condition of riparian vegetation relative

to reference conditions.

Indicator References

Baker, M.B.; Ffolliott, P.F.; DeBano, L.F.; Neary, D.G., eds.

2004. Riparian areas of the Southwestern United States: hydrology, ecology and management. Boca Raton, FL: CRC Press.

DeBano, L.F.; Schmidt, L.J. 1989. Improving riparian areas

through watershed management. Gen. Tech. Rep. RM-182. Fort

Collins, CO: U.S. Department of Agriculture, Forest Service,

Rocky Mountain Forest and Range Experiment Station.

Hornbeck, J.W.; Kochenderfer, J.N. 2000. Linkages between

forests and streams: a perspective in time. In: Verry, E.S.;

Hornbeck, J.W.; Dolloff, C.A., eds. Riparian management in

forests of the continental Eastern United States. Boca Raton,

FL: Lewis Publishers and CRC Press: 89–98.
Watershed Condition Classification Technical Guide 25

National Research Council (NRC). 2002. Riparian areas:

functions and strategies for management. Washington, DC:

National Academy of Science.

Prichard, D.; Anderson, J.; Correll, C., et al. 1998. A user guide

to assessing proper functioning condition and the supporting

science for lotic areas. TR 1737-9. BLM/RS/ST-98/001+1737.

Denver, CO: U.S. Department of the Interior, Bureau of Land

Management, National Applied Resource Sciences Center.

126 p.

Prichard, D.; Bridges, C.; Krapf, R., et al. 1994. Riparian area

management: process for assessing proper functioning condition for lentic riparian-wetland areas. TR 1737-11. BLM/SC/

ST-94/008+1737. Denver, CO: U.S. Department of the Interior,

Bureau of Land Management, Denver Service Center. 136 p.
26 Watershed Condition Classification Technical Guide

6. Roads and Trails Condition 

Purpose

This indicator addresses changes to the hydrologic and sediment regimes due to the density, location, distribution, and maintenance

of the road and trail network.

Condition Rating Rule Set

6. Roads 

and Trails 

Condition 

Indicator

The density and distribution of

roads and linear features within the

watershed indicate that the hydrologic

regime is substantially intact and

unaltered.

The density and distribution of

roads and linear features within

the watershed indicates that there

is a moderate probability that the

hydrologic regime is substantially

altered.

The density and distribution of

roads and linear features within the

watershed indicates that there is a

higher probability that the hydrologic

regime (timing, magnitude, duration,

and spatial distribution of runoff

flows) is substantially altered.

Attributes Good (1) Functioning Properly Fair (2) Functioning at Risk Poor (3) Impaired Function

Open road 

density

Default road/trail density: less than

1 mi/mi2

, or a locally determined

threshold for good conditions supported by forest plans or analysis

and data.

Default road/trail density: From 1 to

2.4 mi/mi2, or a locally determined

threshold for fair conditions supported

by forest plans or analysis and data.

Default road/trail density: more than

2.4 mi/mi2, or a locally determined

threshold for poor conditions supported by forest plans or analysis and

data.

Road and trail 

maintenance

Best Management Practices (BMPs)

for the maintenance of designed

drainage features are applied to more

than 75 percent of the roads, trails,

and water crossings in the watershed.

BMPs for the maintenance of designed drainage features are applied

to 50 to 75 percent of the roads, trails,

and water crossings in the watershed.

BMPs for the maintenance of designed drainage features are applied

to less than 50 percent of the roads,

trails, and water crossings in the

watershed.

Proximity to 

water

No more than 10 percent of road/

trail length is located within 300 feet

of streams and water bodies or hydrologically connected to them.

Between 10 and 25 percent of road/

trail length is located within 300 feet

of streams and water bodies or hydrologically connected to them.

More than 25 percent of road/trail

length is located within 300 feet of

streams and water bodies or hydrologically connected to them.

Mass wasting Very few roads are on unstable

landforms or rock types subject to

mass wasting with little evidence of

active movement or evidence of road

damage. There is no danger of large

quantities of debris being delivered to

the stream channel because of mass

wasting.

A few roads are on unstable landforms or rock types subject to mass

wasting with moderate evidence of

active movement or road damage.

There is some danger of large quantities of debris being delivered to the

stream channel, although this is not a

primary concern in this watershed.

Most roads are on unstable landforms or rock types subject to mass

wasting with extensive evidence of

active movement or road damage.

Mass wasting that could deliver large

quantities of debris to the stream

channel is a primary concern in this

watershed.

Additional Guidance

1.	 For the purposes of this reconnaissance-level assessment,

the term “road” is broadly defined to include roads and

all lineal features on the landscape that typically influence

watershed processes and conditions in a manner similar to

roads. Roads, therefore, include Forest Service system roads

(paved or nonpaved) and any temporary roads (skid trails,

legacy roads) not closed or decommissioned, including

private roads in these categories. Other linear features that

might be included based on their prevalence or impact in

a local area are motorized (off-road vehicle, all-terrain

vehicle) and nonmotorized (recreational) trails and linear

features, such as railroads. Properly closed roads should

be hydrologically disconnected from the stream network.

If roads have a closure order but are still contributing to

hydrological damage they should be considered open for the

purposes of road density calculations.

2.	 Open road density. Although default road density guidelines

(USFWS 1998) for good, fair, and poor conditions are

provided, forests may deviate from the default values based

on local analysis and/or forest plan standards and guidelines.

For example, existing local or regional planning processes,

publications, or other analyses may have established

thresholds that are more pertinent to local conditions. The
Watershed Condition Classification Technical Guide 27

selected default road density guidelines were derived from

U.S. Fish and Wildlife Service guidance that covered a large

geographical area of the Western United States.

3.	Mass wasting. Mass movement is rated only with respect to

the extent and effect it is associated with roads and effects

to aquatic resources. Areas that are inherently unstable or at

risk from mass movement are not rated.

4.	Mass wasting. Geographical areas where mass wasting is

not a significant process, may be rated as N/A. Typically,

this designation would be applied over a broad geographic

area such as an entire national forest. Coordination with the

Regional Oversight Team is suggested to ensure consistency

among adjacent units.

Definitions

hydrologically connected. Any road segment that, during a

high runoff event, has a continuous surface flow path between

the road prism and a natural stream channel is a hydrologically

connected road segment. The proximity of roads to streams is a

surrogate for hydrologic connectivity.

mass wasting. The geomorphic process by which soil, regolith,

and rock move downslope under the force of gravity. Mass

wasting may also be known as slope movement or mass movement. It encompasses a broad range of gravity-driven rock, soil,

or sediment movements, including weathering processes. Types

of mass wasting include creep, slides, flows, topples, and falls,

and they are differentiated by how the soil, regolith, or rock

moves downslope as a whole.

unstable landforms, geologic types, and landslide prone 

areas. Areas determined unstable by individual national forests

using exiting soil resource inventories, terrestrial ecological

unit inventories, geologic inventories, or maps.

Rationale for Indicator

Roads affect watershed condition because more sediment is

contributed to streams from roads and road construction than

any other land management activity. Roads directly alter natural sediment and hydrologic regimes by changing streamflow

patterns and amounts, sediment loading, transport, deposition,

channel morphology and stability, and water quality and riparian conditions within a watershed (Copstead et al. 1997, Dunne

and Leopold 1978, Gibbons and Salo 1973). Road maintenance

can also increase sediment routing to streams by creating areas

prone to surface runoff, altering slope stability in cut-and-fill

areas, removing vegetation, and altering drainage patterns

(Burroughs and King 1989, Luce and Black 2001, Megahan

1978, Reid and Dunne 1984). Road density is known to play

a dominant role in human-induced augmentation of sediment

supply by erosion and mass wasting in upland forested landscapes in the Pacific Northwest (Cederholm et al. 1981, Furniss

et al. 1991), and it is reasonable to assume that similar relationships exist elsewhere. Road-related mass soil movements can

continue for decades after roads have been constructed, and

long-term slope failures frequently occur after road construction and timber harvest (Megahan and Bohn 1989).

Indicator References

Burroughs, E.R., Jr.; King, J.G. 1989. Reduction of soil erosion

on forest roads. Gen. Tech. Rep. INT-264. U.S. Department of

Agriculture, Forest Service, Intermountain Research Station.

Ogden, UT. 21 p.

Cederholm, C.J.; Reid, L.M.; Salo, E.O. 1981. Cumulative

effects of logging road sediment on salmonid populations of the

Clearwater River, Jefferson County, Washington. In: Proceedings: Conference on salmon spawning gravel: a renewable

resource in the Pacific Northwest? Report 19. Pullman, WA:

Washington State University, Water Research Center: 38–74.

Copstead, R.; Moore, K.; Ledwith, T.; Furniss, M. 1997.

Water/road interaction: an annotated bibliography. Water/Road

Interaction Technology Series. Pub. 9777 1816P. Washington,

DC: U.S. Department of Agriculture, Forest Service, Technology and Development Center. 162 p.

Dunne, T.; Leopold, L.B. 1978. Water in environmental planning. New York: W.H. Freeman. 818 p.

Furniss, M.J.; Roelofs, T.D.; Yee, C.S. 1991. Road construction

and maintenance. In: Meehan, W.R., ed. Influences of forest

and rangeland management. Special Publication 19. Bethesda,

MD: American Fisheries Society: 297–324.

Gibbons, D.R.; Salo, E.O. 1973. An annotated bibliography of

the effects of logging on fish of the Western United States and

Canada. Gen. Tech. Rep. PNW-10. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest

and Range Experiment Station. 145 p.

Luce, C.H.; Black, T.A. 2001. Effects of traffic and ditch

maintenance on forest road sediment production. In: Proceedings: seventh Federal interagency sedimentation conference:

V67–V74.

Megahan, W.F. 1978. Erosion processes on steep granitic road

fills in central Idaho. Soil Society of America Journal. 43(2):

350–357.
28 Watershed Condition Classification Technical Guide

Megahan, W.F.; Bohn, C.C. 1989. Progressive, long-term slope

failure following road construction and logging on noncohesive, granitic soils of the Idaho Batholith. In: Woessner, W.W.;

Potts, D.F., eds. Proceedings: Symposium on headwaters

hydrology, American Water Resources Association: 501–510.

Reid, L.M.; Dunne, T. 1984. Sediment production from forest

road surfaces. Water Resources Research. 20: 1753–1761.

U.S. Fish and Wildlife Service (USFWS). 2000. A framework

to assist in making Endangered Species Act determinations

of effect for individual or grouped actions at the bull trout

subpopulation watershed scale. In: Appendix 9 of the Interior

Columbia Basin Ecosystem Management Project, Supplemental

Draft Environmental Impact Statement. Boise, ID. USDA Forest

Service and Bureau of Land Management. http://www.icbemp.

gov/pdfs/sdeis/Volume2/Appendix9.pdf. (24 March 2011).
Watershed Condition Classification Technical Guide 29

7. Soils Condition

Purpose

This indicator addresses alteration to natural soil condition, including productivity, erosion, and chemical contamination.

Condition Rating Rule Set

7. Soils 

Condition 

Indicator

Minor or no alteration to reference

soil condition, including erosion,

productivity, and chemical

characteristics is evident.

Moderate amount of alteration

to reference soil condition is

evident. Overall soil disturbance is

characterized as moderate.

Significant alteration to reference

soil condition is evident. Overall

soil disturbance is characterized as

extensive.

Attributes Good (1) Functioning Properly Fair (2) Functioning at Risk Poor (3) Impaired Function

Soil productivity Soil nutrient and hydrologic cycling

processes are functioning at near sitepotential levels, and the ability of the

soil to maintain resource values and

sustain outputs is high in the majority

of the watershed.

Soil nutrient and hydrologic cycling

processes are impaired and the ability

of the soil to maintain resource values

and sustain outputs is compromised

in 5 to 25 percent of the watershed.

Soil nutrient and hydrologic cycling

processes are impaired and the ability

of the soil to maintain resource values

and sustain outputs is compromised

in more than 25 percent of the watershed.

Soil erosion Evidence of accelerated surface

erosion is generally absent over the

majority of the watershed.

Evidence of accelerated surface erosion occurs over less than 10 percent

of the watershed, or rills and gullies

are present but are generally small,

disconnected, poorly defined, and not

connected into any pattern.

Evidence of accelerated surface

erosion occurs over more than 10

percent of the watershed, or rills and

gullies are actively expanding, welldefined, continuous, and connected

in a definite pattern.

Soil 

contamination

No substantial areas of soil contamination in the watershed exist. When

atmospheric deposition is a source of

contamination, sulfur and/or nitrogen

deposition is more than 10 percent

below the terrestrial critical load.

Limited areas of soil contamination

may be present, but they do not have

a substantial effect on overall soil

quality. When atmospheric deposition

is a source of contamination, sulfur

and/or nitrogen deposition is 0 to

10 percent below the terrestrial

critical load.

Extensive areas of soil contamination

may be present. When atmospheric

deposition is a source of contamination, sulfur and/or nitrogen deposition

is above the terrestrial critical load.

Additional Guidance

1.	 If forest or regional direction exists for soil quality or soil

management, these local thresholds may be used to determine the appropriate rating for soil attributes.

2.	 Soil nutrient and hydrologic cycling processes are evaluated

using available relevant soil properties such as compaction,

porosity, infiltration, bulk density, organic matter, soil cover,

microbial activity, or other appropriate indicators.

3.	 Soil erosion should not double count road-related erosion

effects that are considered in the roads and trails condition

indicator.

4.	 Atmospheric deposition. Compare current deposition with

either site-specific terrestrial critical loads for acidity and/or

nutrient nitrogen (Geiser et al. 2010, Pardo et al. in review),

or with the best available critical loads calculated for similar

sites in the region. Where acidification is the primary

concern and site-specific critical loads are absent, use the

risk assessment map of exceedence of critical loads (based

on McNulty et al. 2007) to classify the watershed. Current

information (including directions to Geographic Information

System (GIS) coverage) for site-specific, regional, and

national scale critical loads is available at http://www.fs.fed.

us/air.

Definitions

critical load. The amount of deposition of an atmospheric pollutant below which no harmful ecological effects occur. We can

calculate critical loads for both acidity and nutrient nitrogen in

terrestrial and aquatic systems.
30 Watershed Condition Classification Technical Guide

reference soil condition. The condition of the soil with which

functional capacity is compared. Using indicators, soil quality

is usually assessed by comparing a management system with

a reference condition. The reference condition may be represented with (1) baseline measurements taken previously at

the same location; (2) established and achievable indicator

values such as salinity levels related to salt tolerance of crops;

or (3) measurements from the same or similar soil under the

reference state or inherent or attainable conditions (Tugel et al.

2008).

soil condition. A description of soil physical, chemical and

biological properties that affect soil ecosystem services, including productivity, hydrologic function, stability, and resilience.

Rationale for Indicator

Determining natural soil condition includes evaluating erosion, nutrients, productivity, and the physical, chemical, and

biological characteristics of the soil (USDA Forest Service

2009). Soil condition is related to watershed condition because

of significant water supply benefits associated with developing

forest soils that promote infiltration and high-quality water.

Forest soils, with litter layers, high organic content, and large

macropore fraction, promote rapid infiltration and minimize

erosive overland flow (Ice 2009). In other ecosystems, soil

supplies air, water, nutrients, and mechanical support for the

sustenance of plants. It also receives and processes rainfall and

controls how much of that rainfall becomes surface runoff,

how much is stored for slow, sustained delivery to stream

channels, and how much is stored and used for soil processes

(Neary et al. 2005). Management activities, such as intensive

grazing, logging, recreational activity, and other disturbances,

can lead to reduced soil structure, soil compaction, and damage to or loss of vegetative cover. These activities contribute

to increased surface runoff resulting in soil erosion, loss of

nutrients, and a decrease in soil productivity (Meehan and

Platts 1978). The soil contamination attribute addresses various

sources of contaminants, including abandoned mines, illegal

dumping, drug labs, spills, atmospheric deposition, and others.

For atmospheric sources, the critical load standard addresses

the impact of air pollution (sulfur and nitrogen) deposition on

forest soils. Sulfur and/or nitrogen deposition estimates above

the critical load for soil indicate the potential for significant

harmful effects to the forest ecosystem through the accelerated

loss of base cations, a decrease in soil pH, an increased risk of

biologically toxic levels of aluminum released from the soils, or

nitrogen in excess of and detrimental to biological demand.

Indicator References

Geiser, L.G.; Jovan, S.E.; Glavich, D.A.; Porter, M.K. 2010.

Lichen-based critical loads for atmospheric deposition in

Western Oregon and Washington forests, USA. Environmental

Pollution. 158: 2412–2421.

Ice, G.G. 2009. Comments on using forestry to secure

America’s water supply. Journal of Forestry. 107(3): 150.

McNulty, S.G.; Cohen, E.C.; Moore Myers, J.A., et al. 2007.

Estimates of critical acid loads and exceedances for forest soils

across the conterminous United States. Environmental Pollution. 149: 281–292.

Meehan, W.P.; Platts, W.S. 1978. Livestock grazing and the

aquatic environment. Journal of Soil and Water Conservation.

33(6): 274–278.

Neary, D.G.; Ryan, K.C.; DeBano, L.F., eds. 2005. Wildland

fire in ecosystems: effects of fire on soils and water. Gen. Tech.

Rep. RMRS-GTR-42-vol.4. Ogden, UT: U.S. Department of

Agriculture, Forest Service, Rocky Mountain Research Station.

250 p.

Pardo, L.H.; Geiser, L.H.; Goodale, C.L., et al. In review. Assessment of effects of N deposition and empirical critical loads

for nitrogen for ecoregions of the United States. Gen. Tech.

Rep. Washington, DC: U.S. Department of Agriculture, Forest

Service. 200 p.

Tugel, A.J.; Skye, A.W.; Herrick, J.E. 2008. Soil change guide:

procedures for soil survey and resource inventory. Lincoln, NE:

U.S. Department of Agriculture, Natural Resources Conservation Service, National Soil Survey Center. Ver. 1.1.

U.S. Department of Agriculture (USDA), Forest Service. 2009.

Soil management manual. FSM 2550. Washington, DC: U.S.

Department of Agriculture, Forest Service. 9 p.
Watershed Condition Classification Technical Guide 31

8. Fire Regime or Wildfire Condition 

Purpose

This indicator addresses the potential for altered hydrologic and sediment regimes because of departures from historical ranges of

variability in vegetation, fuel composition, fire frequency, fire severity, and fire pattern.

Condition Rating Rule Set

8. Fire Regime 

or Wildfire 

Condition 

Indicator

Low likelihood of losing defining

ecosystem components because of

the presence or absence of fire.

Moderate likelihood of losing defining

ecosystem components because of

the presence or absence of fire.

High likelihood of losing defining

ecosystem components because of

the presence or absence of fire.

Attributes Good (1) Functioning Properly Fair (2) Functioning at Risk Poor (3) Impaired Function

Fire Regime 

Condition Class

Fire Regime Condition Class

(FRCC) 1—A predominate percentage of the watershed is within the

natural (historical) range of variability

(“reference fire regime”) of vegetation

characteristics; fuel composition; fire

frequency, severity, and pattern; and

other associated disturbances. The

vegetative species and cover types

are well adapted to the fire regime

and offer good protection to soil and

water resources.

FRCC 2—A predominate percentage

of the watershed has a moderate departure from the reference fire regime

of vegetation characteristics; fuel

composition; fire frequency, severity,

and pattern; and other associated

disturbances. The vegetative species and cover types are somewhat

affected by the abnormal fire regime

and this results in less protection to

soil and water resources when fire

occurs.

FRCC 3—A predominate percentage

of the watershed has a high departure from the reference fire regime

of vegetation characteristics; fuel

composition; fire frequency, severity,

and pattern; and other associated

disturbances. The vegetative species

and cover types are affected by the

fire regime and this results in periods

of fuel accumulation with infrequent

intense fires with high severity that

are more likely to lead to vegetation

mortality, loss of soil organic matter,

and poor protection to soil and water

resources.

Attributes Good (1) Functioning Properly Fair (2) Functioning at Risk Poor (3) Impaired Function

Wildfire Effects Following a significant wildfire, effects are such that soil and ground

cover conditions in the burned area

are expected to recover within 1 to 2

years to levels that provide watershed

protection appropriate for the location

and ecotype.

Following a significant wildfire,

soil and ground cover conditions

are causing some post-fire runoff

and erosion concerns but are not

sufficient to jeopardize long-term

watershed condition integrity. This

condition may persist for 2 to 5 years

after a wildfire.

Following a significant wildfire, soil

and ground cover conditions are

causing considerable post-fire runoff,

erosion, and flooding threats to watershed condition integrity lasting for

more than 5 years.

Additional Guidance

1.	 The Fire Regime or Wildfire Condition Indicator is unique

in that it is an either/or proposition in which either Fire

Regime Condition or Wildfire Effects is rated. In most

cases, we will rate the Fire Regime attribute. Following a

significant wildfire, however, the Wildfire Effects attribute

is rated and the Fire Regime attribute is rated N/A. This is

the only indicator that operates in this either/or manner.

2.	Wildfire Effects. We will rate watersheds experiencing a

significant wildfire (one that effectively changes the FRCC

using the Wildfire Effects attribute until the watershed fully

recovers from any adverse wildfire effects (i.e., recovers

from a rating of 2 or 3), and during this time we will rate

the FRCC attribute as N/A. Forests should switch to the

Wildfire Effects attribute if more than 50 percent of the

watershed is affected by a significant wildfire. If less than

50 percent of the watershed is affected by a significant

wildfire, switching to this attribute may still be appropriate

and should be determined by the forest on a case-by-case

basis. In the wake of a significant wildfire, only the Wildfire

Effects attribute correctly characterizes the state of the

watershed with respect to watershed condition. For example,

following a severe wildfire, a watershed previously in
32 Watershed Condition Classification Technical Guide

FRCC3 (Poor) reverts to FRCC1 (Good) because it has been

returned to its natural reference condition and the Wildfire

Effects attribute will now be rated as 3 (Poor) due to postfire conditions. Averaging the two attributes will result in an

incorrect characterization of watershed condition. To avoid

this, we will rate watershed condition based on the Wildfire

Effects attribute during the entire watershed recovery period.

3.	 Fire Regime Condition Class. In watersheds that clearly

have more than one FRCC, use the formula below to determine the Category.

Methodology:

a.	 For each 6th-level hydrologic unit code (HUC)

watershed, determine the percentage of the total

watershed area within each of the Fire Regime

Condition Classes (FRCC1, FRCC2, and FRCC3).

Use GIS overlays if possible.

b.	 FRCC1 is assigned a category score of 1, FRCC2

is assigned a category score of 2, and FRCC3 is

assigned a category score of 3.

c.	 Calculate the weighted average fire regime condition

class (FRCCwtavg) using the formula below:

where:

FRCC1 = acres of watershed within Fire Regime Condition

Class 1,

FRCC2 = acres of watershed within Fire Regime Condition

Class 2,

FRCC3 = acres of watershed within Fire Regime Condition

Class 3.

Categorize fire regime condition using the following calculated weighted average FRCC ranges:

Category 1—1.0 to 1.66.

Category 2—1.67 to 2.33.

Category 3—2.33 to 3.0.

4.	 Fire Regime Condition Class. Although the use of national

FRCC map products is encouraged, forests may refine

FRCC as appropriate to fit their local situations.

a.	 Example 1. Forests in the Southern Region may wish

to use the Fire Frequency-Severity Condition Class

and omit the Succession Class Condition Class in their

determination of Watershed Condition ratings since

this seems more appropriate for these ecosystems.

b.	 Example 2. Forests in the Southwest may wish to

use Integrated Forest Resource Management System

(INFORMS) data instead of the national Landscape

Fire and Resource Management Planning Tools

(LANDFIRE) data since it provides a better estimate

of local conditions.

Document and coordinate modifications with your Regional

Oversight Team.

Definitions

Fire Regime Condition Class (FRCC). Fire regime condition classes measure the degree of departure from reference

conditions, possibly resulting in changes to key ecosystem

components, such as vegetation characteristics (species composition, structural stage, stand age, canopy closure, and mosaic

pattern); fuel composition; fire frequency, severity, and pattern;

and other associated disturbances, such as insect and disease

mortality, grazing, and drought. Possible causes of this departure include (but are not limited to) fire suppression, timber

harvesting, livestock grazing, introduction and establishment of

exotic plant species, and introduced insects and disease. FRCC

is strictly a measure of ecological trends.

The three fire regime condition classes are categorized using the

following criteria: FRCC1 represents ecosystems with low (less

than 33 percent) departure and that are still within the estimated

historical range of variability during a specifically defined

reference period; FRCC2 indicates ecosystems with moderate

(33 to 66 percent) departure; and FRCC 3 indicates ecosystems

with high (more than 66 percent) departure from reference

conditions. As described below, departure is based on a central

tendency (or mean) metric and represents a composite estimate

of the reference condition vegetation characteristics; fuel

composition; fire frequency, severity, and pattern; and other

associated natural disturbances. Low departure includes a range

of plus or minus 33 percent deviation from the central tendency.

Characteristic vegetation and fuel conditions are considered to

be those that occurred within the natural fire regime, such as

those found in areas categorized as FRCC1 (low departure).

Uncharacteristic conditions are considered to be those that did

not occur within the natural regime, such as areas that are often

categorized as FRCC2 and FRCC3 (moderate to high departure).

These uncharacteristic conditions include, but are not limited to

the following: invasive species (weeds and insects), diseases,
Watershed Condition Classification Technical Guide 33

“high graded” forest composition and structure (in which, for

example, large, fire-tolerant trees have been removed and small

fire-intolerant trees have been left within a frequent surface fire

regime), or overgrazing by domestic livestock that adversely

effects native grasslands or promotes unnatural levels of soil

erosion (Hann et al. 2004, 2008).

watershed recovery period. The period of time, in years,

that is required for the burned area to develop vegetation and

infiltration conditions sufficient to reduce runoff and erosion

potential to essentially predisturbance conditions. This is a

best estimate of natural regeneration, soil stabilization, and

hydrophobicity reduction, supplemented by any treatments

prescribed (USDA Forest Service 2009).

Rationale for Indicator

To a large extent, watershed condition is controlled by the

composition and density of vegetative cover and the amount of

bare soil resulting from anthropogenic or natural disturbances

that affect the watershed (Neary et al. 2005). Fire primarily

alters vegetation and soil properties, changing hydrologic

and geomorphic processes. In general, the effects of fire are

increased soil water and overland flow that result in accelerated

erosion by a variety of surface and mass movement processes.

The magnitude of the effects on an ecosystem depends to a

large degree on the frequency and intensity of fire and the sensitivity of the ecosystem to disturbance (Swanson 1981). Fire

regime and geomorphic sensitivity may be used to characterize

and contrast the geomorphic consequences of fire in different

ecosystems. For example, frequent, intense fire in highly

erosive landscapes, such as steep-land chaparral in southern

California, is an extremely important component of some

geomorphic systems. The effects of fire are progressively less

significant in ecosystems in which fire is less frequent and/or

less intense. FRCC, which is a measure of vegetation departure

from reference condition, effectively evaluates potential vegetation change effects to watershed condition. Wildfires have

the potential to exert a tremendous influence on the hydrologic

conditions of watersheds in many forest ecosystems depending

on the fire’s severity, duration, and frequency. Wildfire is

the single forest disturbance that has the greatest potential to

change watershed condition (DeBano et al. 1998). An extensive, high-severity wildfire can destroy the vegetation and litter

layer in a watershed and detrimentally alter physical properties

of the soil, including infiltration and percolation capacities.

These cumulative fire effects can change the watershed condition from good to poor, resulting in unacceptable increases to

overland flow, erosion, and soil loss (Neary et al. 2005).

Indicator References

DeBano, L.F.; Neary, D.G.; Ffolliott, P.F. 1998. Fire’s effects

on ecosystems. New York: John Wiley & Sons. 333 p.

Hann, W.; Shlisky, A.; Havlina, D., et al. 2004. Interagency fire

regime condition class guidebook. Last update January 2008:

Version 1.3.0 [Homepage of the Interagency and The Nature

Conservancy Fire Regime Condition Class Web site, U.S.

Department of Agriculture Forest Service, U.S. Department

of the Interior, The Nature Conservancy, and Systems for

Environmental Management]. http://www.frcc.gov.

Hann et al. 2008. Interagency and The Nature Conservancy

Fire Regime Condition Class Web site. U.S. Department of

Agriculture Forest Service, U.S. Department of the Interior,

The Nature Conservancy, and Systems for Environmental

Management. www.frcc.gov.

Neary, D.G.; Ryan, K.C.; DeBano, L.F., eds. 2005 (revised

2008). Wildland fire in ecosystems: effects of fire on soils

and water. Gen. Tech. Rep. RMRS-GTR-42-Vol.4. Ogden,

UT: U.S. Department of Agriculture, Forest Service, Rocky

Mountain Research Station. 250 p.

Swanson, F.J. 1981. Fire and geomorphic processes. In:

Mooney, H.A., et al., tech. coords. Fire regimes and ecosystem

properties. Gen. Tech. Rep. WO-26. Washington, DC: U.S.

Department of Agriculture, Forest Service: 410–420.

U.S. Department of Agriculture (USDA), Forest Service. 2009.

Emergency stabilization, Burned-Area Emergency Response

(BAER). FSM 2523. Washington, DC: U.S. Department of

Agriculture, Forest Service.
34 Watershed Condition Classification Technical Guide

9. Forest Cover Condition

Purpose

This indicator addresses the potential for altered hydrologic and sediment regimes because of the loss of forest cover on forest lands.

Condition Rating Rule Set

9. Forest Cover 

Condition 

Indicator

The amount of National Forest

System (NFS) forest land in the

watershed that is not supporting

forest cover is minor.

The amount of NFS forest land in

the watershed that is not supporting

forest cover is moderate.

The amount of NFS forest land in

the watershed that is not supporting

forest cover is high.

Attributes Good (1) Functioning Properly Fair (2) Functioning at Risk Poor (3) Impaired Function

Loss of forest 

cover

Less than 5 percent of NFS land in

the watershed contains cut-over,

denuded, or deforested forest land

where appropriate forest cover

should be reestablished or restored

to achieve the desired conditions or

other applicable forest plan direction

for NFS lands.

Between 5 and 15 percent of NFS

land in the watershed contains cutover, denuded, or deforested forest

land where appropriate forest cover

should be reestablished or restored

to achieve the desired conditions or

other applicable forest plan direction

for NFS lands.

More than 15 percent of NFS land

in the watershed contains cut-over,

denuded, or deforested forest land

where appropriate forest cover

should be reestablished or restored

to achieve the desired conditions or

other applicable forest plan direction

for NFS lands.

Additional Guidance

1.	 This indicator focuses on the presence or absence of forest

cover (lands being managed as natural or seminatural forest

ecosystems) on NFS lands in consideration of National

Forest Management Act (NFMA) requirements. Because

non-NFS lands do not have this Federal legal standard for

forest cover, those private and other ownerships are not

included in rating the watershed for this indicator.

2.	 This indicator may be rated N/A if forest cover (as precisely

defined below) is absent in the watershed. If forest cover is

rated N/A, rangeland condition must be rated. In effect, we

characterize a watershed as having forest cover, rangelands,

or both. In many watersheds, we will rate both indicators.

Note that lands that meet the forest land definition will also

normally have a rangeland component to the understory.

This is especially true in those forest lands where the tree

cover is relatively sparse (normally less than 60 percent

canopy cover), with the amount of rangeland vegetation increasing as tree canopy cover decreases. In these instances,

both indicators shall be evaluated and rated.

3.	We will produce the most accurate and rapid assessment

if the Forest Service Activity Tracking System (FACTS)

database reflects current conditions regarding loss of forest

cover and planned or subsequent reforestation activities. Use

sources such as Rapid Assessment of Vegetation Condition

After Wildfire to update FACTS until field exams can be

conducted. Apply FACTS business rules.

4.	Methodology:

a.	 Calculate percent for each 6th-level HUC watershed

using the formula below:

(100)

AT

AD

where:

AD = area (in acres) of NFS forest land within the

watershed that is not providing forest cover. NFS forest land must meet all three of the following criteria:

i.	 is being managed as forest land (a land-use

determination defined by the land and resources

management plan).

ii.	 has been cut over, denuded, or lost forest cover from

any human or natural disturbance.

iii.	 where forest cover has not yet been reestablished.

See the definition of “forest cover” below.

AT = total area (in acres) of NFS forest land within the

watershed. Obtain from best source such as NRMNatural Resource Information Systems (NRIS),

legacy databases, other assessments, remote sensing,

or GIS sources.
Watershed Condition Classification Technical Guide 35

b.	 Using the percentage determined from step a,

categorize each watershed’s forest cover condition

into either Category 1, 2, or 3.

Definitions

forest cover. Areas where trees provide 10 percent or greater

canopy cover and are part of the dominant (uppermost)

vegetation layer, including areas that have been planted to

produce woody crops. For the purposes of watershed condition assessment, lands that do not yet provide 10 percent tree

canopy cover will be considered as meeting the definition of

forest cover if the areas have been certified and recorded in

FACTS as having been regenerated to appropriate forest cover

(whether through natural or artificial regeneration) as specified

in the land and resources management plan. “Appropriate forest

cover” may be defined in one or more of the following forest

plan components (desired conditions, standards, guidelines,

management area prescriptions and allocation map, map of

lands suitable for timber production, or other direction). The

following FACTS codes are applicable (these are used to

generate the Reforestation Needs Report): Harvest Codes 4101,

4102, 4110-17, 4131-34, 4143, 4147, 4150-52, 4160, 4162,

4175-77, 4183, and 4194; Causal Agent: 4250, 4260, 4265,

4270, 4280, and 4290.

forest land. Land is at least 10 percent occupied by forest

trees, or it previously had such tree cover, is and not currently

developed for nonforest use. Lands developed for nonforest

use include areas for crops, improved pasture, residential,

or administrative areas, improved roads of any width, and

adjoining road clearing and power-line clearing of any width

(FSM 1905). Note: Designated wilderness, roadless areas, and

unproductive forest land that meet the above definition are

classified as forest land.

Rationale for Indicator

This is a foundational indicator of whether forest ecosystems

are being sustained or lost over time (“Maintain forests as

forests”). The ability of forests to regulate water flows and

maintain quality supplies is affected by the condition of the

forest and the occurrence of disturbances that change the structure, composition, and pattern of forest vegetation. Forest cover

is a primary terrestrial ecosystem component that is important

to watershed condition. Trees provide many water- and soilrelated ecosystem services such as intercepting precipitation

and protecting soil, regulating snowmelt, and stabilizing steep

slopes. Extensive loss of forest cover because of severe wildfires, widespread insect and disease epidemics, timber harvest,

weather events, and long-term drought affect runoff, erosion,

sediment supply, bank stability, large woody debris retention,

and stream temperature relationships (MacDonald et al. 1991,

Meehan 1991, Reid 1993). Many of the effects from these and

similar disturbances decrease after the initial disturbance but

may remain above natural levels for many years (Platts and

Megahan 1975). Carefully designed and executed management

actions can both restore vegetative cover and improve watershed condition.

Section 4 (Reforestation) of the Forest and Rangeland Renewable Resources Planning Act of 1974, as amended by NFMA

(National Forest Management Act of 1976) (16 U.S.C. 1601(d)

(1)), establishes the policy of Congress that all forested lands in

the NFS be maintained in appropriate forest cover with species

of trees, degree of stocking, rate of growth, and conditions of

stand designed to secure the maximum benefits of multiple-use

sustained yield management in accordance with land management plans.

Regarding private lands, note that some States (such as California) have forest regulations requiring reestablishment or

maintenance of forest cover after timber harvest.

Indicator References

MacDonald, L.H.; Smart, A.; Wissmar, R.C. 1991. Monitoring

guidelines to evaluate effects of forestry activities on streams in

the Pacific Northwest and Alaska. EPA/910/9-91-001. Seattle,

WA: U.S. Environmental Protection Agency, Region 10. 166 p.

Meehan, W.R., ed. 1991. Influences of forest and rangeland

management on salmonid fishes and their habitat. Special

Publication 19. Bethesda, MD: American Fisheries Society.

Platts, W.S.; Megahan, W.F. 1975. Time trends in riverbed

sediment composition in salmon and steelhead spawning areas.

In: Proceedings, 40th American wildlife and natural resources

conference: 229–239.

Reid, L.M. 1993. Research and cumulative watershed effects.

Gen. Tech. Rep. PSW-GTR-141. Albany, CA: U.S. Department

of Agriculture, Forest Service, Pacific Southwest Research

Station. 118 p.

U.S. Government. 1974. Forest and Rangeland Renewable

Resources Planning Act of 1974, as amended by the National

Forest Management Act of 1976 (16 United States Code

1600-1614, 472a).
36 Watershed Condition Classification Technical Guide

10. Rangeland Vegetation Condition

Purpose

This indicator addresses impacts to soil and water relative to the vegetative health of rangelands.

Condition Rating Rule Set

10. Rangeland 

Vegetation 

Condition 

Indicator

Rangelands reflect native or desired

nonnative plant composition and

cover at near-natural levels as defined

by the site potential.

Rangelands reflect native or desired

nonnative plant composition and

cover with slight to moderate

deviation compared to natural levels

as defined by the site potential.

Rangelands reflect native or desired

nonnative plant composition and

cover are greatly reduced or unacceptably altered compared to natural

levels as defined by the site potential.

Attributes Good (1) Functioning Properly Fair (2) Functioning at Risk Poor (3) Impaired Function

Rangeland 

vegetation 

condition

Vegetation contributes to soil

condition, nutrient cycling, and

hydrologic regimes at near-natural

levels; functional/structural groups,

number of species, plant mortality

and decadence closely match that

expected for the site average annual

plant production equals or exceeds

70 percent of production potential;

litter amount is approximately what

is expected for the site potential and

weather; the reproductive capacity of

native or naturalized perennial plants

to produce seeds or vegetative tillers

is sustainable over the long term;

and introduced plant species are

being managed to facilitate long-term

replacement by site-adapted native

species.

Functional/structural groups and

number of species are slightly to

moderately reduced; some dead and/

or decadent plants are present above

what would be expected for the site;

average annual plant production is 40

to 69 percent of production potential;

litter amount is moderately less than

would be expected relative to site potential and weather; the reproductive

capacity of perennial native or naturalized plants to produce seeds or

vegetative tillers is somewhat reduced

but is still sustainable over the long

term; and, introduced plant species

are being managed to facilitate longterm replacement by site-adapted

native species or to ensure adequate

ground cover to protect the soil.

Functional/structural groups and

number of species are moderately to

greatly reduced or altered relative to

site potential; dead and/or decadent

plants are significantly more common

than would be expected for the site;

average annual plant production is

less than 40 percent of production

potential; litter is largely absent or

is sparse and disconnected relative to site potential and weather;

the reproductive capacity of native

or naturalized perennial plants to

produce seeds or vegetative tillers

(native or seeded) is severely reduced

relative to site potentials; and introduced plant species are dominant

and are not effective in protecting the

site and soil.

Additional Guidance

1.	 Rangelands are rated relative to biotic integrity. Use guidance and definitions found in the publication, “Interpreting

Indicators of Rangeland Health” (Pellant et al. 2005), to

assist with this evaluation. Because of the close interrelationship between soils, hydrology, and vegetation condition,

rangeland ecologists, hydrologists, and soil scientists are

encouraged to work together to make this evaluation.

Rangeland soil/ and site stability and hydrologic function

are rated in the Soils Condition indicator. Invasive species

are rated in the Terrestrial Invasive Species Condition

Indicator.

2.	 If forest plan rangeland direction exists for ecological

condition (functional structural groups, plant mortality and

decadence, annual production, litter amounts, reproductive

capacity, or similar attributes), use the local thresholds derived from forest plan standards and guidelines to determine

the appropriate rating.

3.	 This indicator may be rated N/A if rangelands (as defined

below) are absent in the watershed. If rangeland is rated

N/A, forest cover condition must be rated. In effect, we

characterize a watershed as having forest cover, rangelands,

or both. In many watersheds, we will rate both indicators. If

rangelands are not present, we may decide to exclude them

on an individual watershed basis, but in many cases the decision will apply to an entire national forest. Coordination with

the Regional Oversight Team is recommended.

Definitions

biotic integrity (integrity of the biotic community). Capacity of

a site to support characteristic functional and structural communities in the context of normal variability, to resist loss of this
Watershed Condition Classification Technical Guide 37

function and structure because of a disturbance, and to recover

following such disturbance (Pellant et al. 2005).

functioning at risk. Rangelands that have a reversible loss in

productive capability and increased vulnerability to irreversible

degradation based upon an evaluation of current conditions of

the soil and ecological processes (National Research Council

1994).

functioning properly. Rangelands that are functioning properly relative to the ecological site description and/or ecological

reference area given the normal range of variability associated

with the site and climate.

impaired. Rangelands on which degradation has resulted in

the loss of ecological processes that function properly and the

capacity to provide values and commodities to a degree that

external inputs are required to restore the health of the land

(National Research Council 1994).

rangeland. Land on which the indigenous vegetation (climax

or natural potential) is predominantly grasses, grass-like plants,

forbs, or shrubs and is managed as a natural ecosystem. If

plants are introduced, they are managed similarly. Rangelands

include natural grasslands, savannas, shrub lands, many deserts,

tundra, alpine communities, marshes, and wet meadows

(Society of Range Management 1999). (Pellant et al. 2005)

include oak and pinyon-juniper woodlands in this definition). In

this assessment, we will rate the condition of marshes under the

Riparian/Wetland Vegetation indicator.

Rationale for Indicator

Rangeland health is a function of (1) soil/site stability—the

capacity of the site to limit redistribution and loss of soil

resources (including nutrients and organic matter) by wind

and water; (2) hydrologic function—the capacity of the site to

capture, store, and safely release water from rainfall, runoff,

and snowmelt and to recover following disturbance; and (3) the

integrity of the biotic community—the capacity of the site to

support ecological processes within the normal range of variability expected for the site and to recover after a disturbance

(Pellant et al. 2005). Improper management can decrease

ground cover and reduce species diversity, composition and/

or cover. Improper management can result in diminished

watershed functionality through soil compaction, which may

increase overland flow and lead to incised channels and bank

erosion (Bohn and Buckhouse 1986, Kaufman and Kreuger

1984, Platts 1991). Conversely, proper management can

lessen adverse effects (Clary and Webster 1989). In summary,

rangeland vegetative communities that are functioning properly

provide for conditions that sustain soil stability, hydrologic

function, and biotic diversity.

Indicator References

Bohn, C.C.; Buckhouse, J.C. 1986. Effects of grazing management on streambanks. Proceedings: North American wildlife

natural resource conference. 51: 265–271.

Clary, W.P.; Webster, B.F. 1989. Managing grazing of riparian

areas in the Intermountain Region. Gen. Tech. Rep. INT-263.

Ogden, UT: U.S. Department of Agriculture, Forest Service,

Intermountain Research Station. 11 p.

Johnson, K.L. 1992. Management for water quality on rangeland through best management practices: the Idaho approach.

In: Watershed management: balancing sustainability and

environmental change. New York: Springer-Verlag: 415–441.

Kaufmann, J.B.; Kreuger, W.C. 1984. Livestock impacts on

riparian ecosystems and streamside management implications:

a review. Journal of Range Management. 37: 430–438.

National Research Council. 1994. Rangeland health: new methods to classify, inventory, and monitor rangelands. Washington,

DC: National Academy Press, National Research Council. 180 p.

Pellant, M.; Shaver, P.; Pyke, D.A.; Herrick, J.E. 2005.

Interpreting indicators of rangeland health. Tech. Ref. 1734-6.

BLM/WO/ST-00/001+1734/REV05. Denver, CO: U.S. Department of the Interior, Bureau of Land Management, National

Science and Technology Center. 122 pp. Ver. 4. http://www.

blm.gov/nstc/library/pdf/1734-6rev05.pdf. (24 March 2011).

Platts, W.S. 1991. Livestock grazing. In: Influence of forest and

rangeland management on salmonid fishes and their habitats.

Special Publication 19. Bethesda, MD: American Fisheries

Society: 389–423.

Society for Range Management. 1999. A glossary of terms

used in range management. Denver, CO: Society for Range

Management. 20 p.
38 Watershed Condition Classification Technical Guide

11. Terrestrial Invasive Species Condition

Purpose

This indicator addresses potential impacts to soil, vegetation, and water resources due to terrestrial invasive species (including

vertebrates, invertebrates, and plants).

Condition Rating Rule Set

11. Terrestrial 

Invasive 

Species 

Condition 

Indicator

Few or no populations of terrestrial

invasive species infest the watershed

that could necessitate removal

treatments that would affect soil and

water resources.

Populations of terrestrial invasive

species are established within

the watersheds and/or the rate of

expansion and/or potential for impact

on watershed resources is moderate.

Terrestrial invasive species populations infest significant portions of

the watershed, are expanding their

range, and there is documentation

of widespread impacts to watershed

resources.

Attributes Good (1) Functioning Properly Fair (2) Functioning at Risk Poor (3) Impaired Function

Extent and rate 

of spread

Few (less than 10 percent) or no

populations of terrestrial invasive

species infest the watershed that

could necessitate removal treatments

to protect, soil, native vegetation, or

other water resources. Those that occur are small in extent and scattered

in nature. The rate of spread and/

or potential for impact on watershed

resources is minimal or unlikely.

Management intervention may be

necessary to prevent increased risk of

spread or invasion. Integrated management treatments may temporarily

negatively affect soil, native vegetation, and other water resources, but

the scale and scope would be minor.

Populations of terrestrial invasive

species are established within (10 to

25 percent) the watershed and/or the

rate of spread and/or potential for impact on soil, vegetation, or other water resources is moderate. Integrated

treatments affect 10 to 25 percent of

the watershed and must be ongoing

just to keep the invasive species in

check. Management intervention will

be required to prevent increased level

of risk.

Populations of terrestrial invasive

species infest significant portions

(more than 25 percent) of the watershed, may be expanding their range,

and widespread impacts to soil,

native vegetation, or other water

resources have been documented.

Treatments for containment affect

more than 25 percent of the watershed, and management adjustments

and/or treatments need to be ongoing

just to keep the invasive species in

check. Management intervention is

necessary to alleviate significant

resource damage and increased

degradation of watershed condition.

Additional Guidance

1.	 This indictor applies only to terrestrial vertebrates,

invertebrates, and plants that may have an adverse effect on

soil and water resources. Aquatic invasive species are considered under Aquatic Biota Condition. Invasive insects and

pathogens (including native forest insect pests and diseases)

are covered under the Forest Health indicator.

2.	 Infestation extent. Infestation extent is usually evaluated

with risk assessments and other inventory and evaluation

procedures at either the species level, site level, or project

level. For example, the extent of the terrestrial invasive species infestation on an individual species-level may indicate

that the watershed condition rating is “good,” but when

viewed within the context of all the documented terrestrial

invasive species infesting the entire watershed, the overall

condition rating may be considered “poor.”

3.	 Integrated management treatments against terrestrial invasive

species may temporarily negatively affect soil, native vegetation, and other watershed resources, requiring a restoration

component to the project plan.

Definitions

native species. With respect to a particular ecosystem, a species

that historically occurred in that ecosystem.

terrestrial invasive species. A terrestrial invasive species

(including vertebrates, invertebrates, pathogens, and plants) is

a species not native to the ecosystem location under consideration, and its introduction causes or is likely to cause economic

or environmental harm, or harm to human health. The lack of

natural ecological controls (which typically kept these exotic

species regulated in their native home) allows these exotic

species to significantly harm the areas they invade. Terrestrial

invasive species refers to harmful exotic species that are found
Watershed Condition Classification Technical Guide 39

or occur on the land surface rather than in aquatic environments. Many exotic plant and animal species occupy terrestrial

habitats, but they are not necessarily harmful and typically

cause little to no economic or environmental damage, and do

not out-compete or displace native plants or animals.

Rationale for Indicator

When they produce significant changes in ecological processes,

invasive species may cause environmental harm to watershed

conditions, sometimes across broad geographical areas, which

results in conditions that native animal and plant communities

cannot tolerate. Some invasive species can significantly alter

effective ground cover, erosion rates, and nutrient cycling;

change the frequency and intensity of wildfires; or alter the

hydrology of rivers, streams, lakes, and wetlands (Mack et al.

2000). For example, for cheatgrass the link to soil and hydrologic

processes is through a chain of logic that recognizes that while

cheatgrass may seasonally provide adequate cover for watershed protection, because it is an annual that it leaves little

to no vegetative soil protection in dry years to provide soil

protection. Consequently, its overall ability to protect the soil

is minimal (and is well outside of the native site potential).

Also, since disturbance of the soil is the main reason cheatgrass

spreads, it is closely associated with an undesirable condition

from a soil and water perspective. Cheatgrass in the Great

Basin region has been shown to decrease the interval between

the occurrences of wildfires from once every 70 to 100 years to

every 3 to 5 years because it forms dense stands of fine fuel annually. This decrease in interval between wildfires causes more

severe soil erosion and dramatically alters desirable native plant

communities (Knapp 1996; Pimentel et al. 2000). Similarly,

tamarisk (salt cedar) [Tamarix spp.] in the Southwest disrupts

the structure and stability of North American native riparian

plant communities by out-competing and replacing native plant

species, increasing soil salinity, monopolizing limited sources

of moisture, and increasing the frequency, intensity, and effect

of fires and floods. Tamarisk has taken over large sections of

riparian ecosystems in the Western United States that were

once home to native cottonwoods and willows (Christensen

1962; Stromberg 1998). In addition, infestations of terrestrial

invasive vertebrate species such as wild (feral) pigs cause

widespread soil erosion, harbor infectious diseases, damage

native vegetation, and aggressively prey upon native vertebrate

and invertebrate wildlife (USDA-APHIS 1999).

Indicator References

Christensen, E.M. 1962. The rate of naturalization of Tamarix

in Utah. American Midland Naturalist. 68(1): 51–57.

Knapp, P.A. 1996. Cheatgrass (Bromus tectorum L.) dominance

in the Great Basin Desert: history, persistence, and influences to

human activities. Global Environmental Change. 6(1): 37–52.

Mack, R.; Simberloff, D.W.M.; Lonsdale, H., et al. 2000.

Biotic invasions: causes, epidemiology, global consequences,

and control. Ecological Applications. 10: 689–710.

Pimentel, D.; Lach, L.; Zuniga, R.; Morrison, D. 2000. Environmental and economic costs of nonindigenous species in the

United States. Bioscience. 50(1): 53–65.

Stromberg, J.C. 1998. Functional equivalency of saltcedar

(Tamarix chinensis) and Fremont cottonwood (Populus fremontii) along a free-flowing river. Wetlands. 18: 675–686.

U.S. Department of Agriculture (USDA), Animal and Plant

Health Inspection Service (APHIS). 1999. Wild pigs: hidden

danger for farmers and hunters. Agricultural Information

Bulletin. 620: 3–7.
40 Watershed Condition Classification Technical Guide

12. Forest Health Condition

Purpose

This indicator addresses forest mortality impacts to hydrologic and soil function due to major invasive and native forest pest, insect,

and disease outbreaks and air pollution.

Condition Rating Rule Set

12. Forest 

Health 

Condition 

Indicator

A small amount of the forested land

in the watershed is anticipated to

experience or is experiencing tree

mortality from insects and disease

and from air pollution.

A moderate amount of the forested

land in the watershed is anticipated

to or is experiencing tree mortality

from insects and disease and from air

pollution.

A large amount of the forested land

in the watershed is anticipated to or

is experiencing tree mortality from

insects and disease and from air

pollution.

Attributes Good (1) Functioning Properly Fair (2) Functioning at Risk Poor (3) Impaired Function

Insects and 

disease

Less than 20 percent of the forested

land in the watershed is at imminent

risk of abnormally high levels of tree

mortality (a level of 25 percent in

a stand is deemed to represent an

uncommon, rather extraordinarily

high amount of mortality) because of

insects and disease.

Between 20 and 40 percent of the

forested land in the watershed is

at imminent risk of abnormally high

levels of tree mortality (a level of 25

percent is deemed to represent an

uncommon, rather extraordinarily

high amount of mortality) because of

insects and disease.

More than 40 percent of the forested

land in the watershed is at imminent

risk of abnormally high levels of tree

mortality (a level of 25 percent is

deemed to represent an uncommon,

rather extraordinarily high amount

of mortality) because of insects and

disease.

Ozone Ozone causes a decrease in biomass

growth in fewer than 20 percent of the

years evaluated.

Ozone causes a decrease in biomass

growth in 20 to 40 percent of the

years evaluated.

Ozone causes a decrease in biomass

growth in more than 40 percent

of the years evaluated, and/or the

watershed is within an area exceeding the National Ambient Air Quality

Standards for ground-level ozone.

Additional Guidance

1.	 Insects and disease. Once outbreaks occur, we can do very

little to halt or slow the spread, thus in this condition classification, we treat the presence of imminent outbreaks as if

the undesirable condition already exists.

2.	 Insects and disease. Forests will use the 2006 National

Insect and Disease Risk Map (NIDRM) (Krist et al. 2007) as

a beginning point for evaluating potential future conditions.

Areas at risk on NIDRM represent locations at which current

stand or ecological conditions indicate that potential exists

for insect and disease activity in the near term (i.e., next

15 years) if remediation is not undertaken. NIDRM is an

integration of 188 individual risk models constructed within

a common framework that is adaptable to regional variations

in current and future forest health. The 2006 risk assessment

introduced a consistent, repeatable, transparent process from

which spatial and temporal risk assessments were at various

scales. Primary contributors to the risk of mortality included

mountain pine beetle, oak decline on red oaks, southern pine

beetle, root diseases, gypsy moth, pine engraver beetle, fir

engraver beetle, Douglas-fir beetle, spruce beetle, hardwood

decline, and western pine beetle. The threshold for mapping

risk is the following: the expectation that, without remediation, 25 percent or more of the standing live basal area on

trees greater than 1 inch in diameter will die over the next

15 years because of insects and diseases. Krist et al. (2007)

mapped watersheds most at risk at the 4th-level HUC (see

fig. 11) showing the percentage of forested lands at risk. The

lowest risk category (0–20 percent) is assigned as Condition Rating 1, the 20 to 40 percent category is assigned as

Condition Rating 2, and more than 40 percent is assigned

as Condition Rating 3. These breakpoints are consistent

with recent investigations of watershed impacts following

mountain pine beetle outbreak in Fraser Experimental Forest

in Colorado (Rhoades et al. 2008).

3.	 Insects and disease. Finer scale maps at the 6th-level HUCs

are available from the Forest Health Technology Enterprise

Team (FHTET) in Fort Collins, CO.
Watershed Condition Classification Technical Guide 41

4.	 Insect and disease detection surveys. Aerial sketch mapping

is the primary data-collection method for this annual dataset.

Observers code polygon data with damage agent, damage

type, and a range of other possible attributes including host,

severity, and approximate dead trees per acre. Data describing the condition within the polygon can be continuous or

discontinuous and serves mostly as a snapshot in time of

current and past activity. These data are subjective in nature,

but may add valuable information for watershed assessment,

particularly in areas where large mortality or defoliation

events have occurred. Information about Forest Service

Insect and Disease Detection Surveys are available from

http://www.fs.fed.us/foresthealth/technology/adsm.shtml.

Contact the local Forest Health Specialist for assistance with

assessment of current insect or disease outbreaks.

5.	 Ozone. Assessments should use data from a nearby ambient ozone monitor or the national GIS coverage based

on the ozone monitoring network. The attribute rating is

determined by the percentage of years during which modeling shows that biomass growth is reduced by 10 percent

or more. Contact the local Air Specialist or Forest Health

Specialist for assistance with this analysis.

6.	 Ozone. Any years where the soil moisture is low (i.e., during

a drought), the watershed(s) should be classified as “Good”

because it is unlikely the ozone exposures contributed to any

biomass reductions.

7.	 Ozone. The forests are encouraged to obtain ozone bioindicator data from the national Forest Health Monitoring

program or by conducting field surveys if a watershed is

consistently being rated as poor. The presence of ozone

symptoms on ozone-sensitive species indicates a physiological response to the chronic or acute ozone exposure.

Rationale for Indicator

Healthy forests are an important component of watershed

health. Two primary influences on forest health are insects and

disease, and air pollution. Insects and disease along with fire

are important regulators of forest change. Insects and disease

can negatively affect resource values and ecosystem functions

including reducing the ability of forest canopies to intercept

snow and prevent excessive runoff. Recent increases in insect

outbreaks have created a resurgence of interest in their effects

on water quantity, water quality, and increased fire risks.

Relatively few studies have examined the hydrologic response

of forests to insects and disease, especially at long-term scales

or in large watersheds (WSTB 2008). Although we still have

much to understand, we can extrapolate the effects of insects

and disease on watershed condition from general principles

derived from studies of timber harvest and fire (MacDonald and

Stednick 2003). Investigations of a recent outbreak of mountain

pine beetle (Dendroctonus ponderosae) in Fraser Experimental

Forest in Colorado indicate that spring and fall nitrate concentrations were 30 percent higher during 6 years following

onset of bark beetle activity than preoutbreak concentrations

(Rhoades et al. 2009). Air pollution effects are addressed by

the effect of ground-level ozone on forest vegetation. Ozone

can cause reductions in photosynthesis, which can decrease the

amount of root growth, tree height, and crown width, which

makes the weakened trees more susceptible to insect attacks

(Lefohn 1992, Lefohn and Runeckles 1987).

Indicator References

Krist, F.J., Jr.; Sapio, F.J.; Tkacz, B.M. 2007. Mapping risk

from forest insects and diseases. FHTET 2007-06. Washington

DC: U.S. Department of Agriculture, Forest Service, Forest

Health Protection, Forest Health Technology Enterprise Team.

http://www.fs.fed.us/foresthealth/technology/nidrm.shtml.

(August 2007).

Lefohn, A.S. 1992. Ozone standards and their relevance for

protecting vegetation. In: Lehohn, A.S., ed. Surface-level ozone

exposure and their effects on vegetation. Chelsea, MI: Lewis

Publishers: 325–359.

Lefohn, A.S.; Runeckles, V.C. 1987. Establishing a standard

to protect vegetation—ozone exposure/dose considerations.

Atmospheric Environment. 21: 561–568.

MacDonald, L.H.; Stednick, J.D. 2003. Forests and water: a

state-of-the-art review for Colorado. Colorado Water Resources

Research Institute Rpt. No. 196. Denver, CO: Colorado Water

Resources Research Institute.

Rhoades, C.; Elder, K.; Hubbard, R.; Dixon, M. 2008. Streamwater nitrogen during mountain pine beetle infestation of subalpine watersheds at the U.S. Forest Service, Fraser Experimental

Forest. Poster presented at American Geophysical Union, fall

meeting 2008. http://www.fs.fed.us/rm/boise/AWAE/scientists/

profiles/Rhoades/AGU_FEF_MPB_final.pdf. (24 March 2011).

Water Science and Technology Board (WSTB). 2008. Hydrologic effects of a changing forest landscape. Washington, DC:

National Academies Press, Committee on Hydrologic Impacts

of Forest Management. http://www.nap.edu/openbook.php?

record_id=12223&page=R1. (24 March 2011).