Forest

Service

United States Department of Agriculture

General Technical Report 

RMRS-GTR-394

Rocky Mountain

Research Station June 2019

Riparian Ecosystems of the Salmon-Challis National 

Forest: An Assessment of Current Conditions 

in Relation to Natural Range of Variability

Katelyn P. Driscoll

D. Max Smith

Steven D. Warren

Deborah M. Finch
Driscoll, Katelyn P.; Smith, D. Max; Warren, Steven D.; Finch, Deborah M. 2019. Riparian 

ecosystems of the Salmon-Challis National Forest: An assessment of current conditions 

in relation to the natural range of variability. Gen. Tech. Rep. RMRS-GTR-394. Fort Collins, 

CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 190 p. 

Abstract 

This assessment was conducted to provide information on the current conditions of riparian, 

wetland, and groundwater-dependent ecosystems in reference to their natural range of variation 

on the Salmon-Challis National Forest during forest plan revision. We used peer-reviewed 

literature, data from the Forest and other partners, and site visits to evaluate the status of eight key 

ecosystem characteristics: (1) distribution and connectivity of riparian ecosystems, (2) distribution 

of groundwater-dependent ecosystems, (3) surface water and groundwater fluctuations, (4) water 

quality, (5) channel and floodplain dynamics, (6) condition of spring runout channel, (7) composition 

and condition of riparian ecosystems, and (8) composition and condition of groundwater-dependent 

ecosystems. We determined that riparian, wetland, and groundwater-dependent ecosystems of the 

National Forest have experienced stressors that have influenced their current conditions, including 

livestock and wild ungulate grazing, altered streamflow and fire regimes, road construction, timber 

harvest, invasive and encroaching species, vegetation mortality due to insects and disease, 

and altered temperature and precipitation regimes. Some units of the Forest, particularly the 

North Fork Ranger District and sections of the Salmon-Cobalt and Middle Fork Ranger Districts, 

appear to be more resistant and resilient to stressors. Our results have been incorporated in 

ecosystem assessments completed during the forest plan revision process and will be useful to 

resource managers and planners during efforts to restore and/or maintain riparian, wetland, and 

groundwater-dependent ecosystems on the Salmon-Challis National Forest. 

Keywords: forest plan, key ecosystem characteristic, riparian vegetation, flow regime, 

 channel morphology, floodplain

All Rocky Mountain Research Station publications are published by U.S. Forest Service employees and 

are in the public domain and available at no cost. Even though U.S. Forest Service publications are not 

copyrighted, they are formatted according to U.S. Department of Agriculture standards and research 

findings and formatting cannot be altered in reprints. Altering content or formatting, including the cover 

and title page, is strictly prohibited.

Cover photo

Black cottonwoods (Populus trichocarpa) along Morse creek, with the Pahsimeroi Valley and Lost 

River Range in the background (photo by D.M. Smith, USDA Forest Service). 
Authors

Katelyn P. Driscoll is a Research Ecologist with the Rocky Mountain Research Station at the 

Forestry Science Laboratory in Albuquerque, New Mexico. She completed a B.S. degree in 

Biology and minor in Spanish at Gonzaga University, Spokane, Washington, and an M.S. degree in 

Systems Ecology at the University of Montana, Missoula, Montana.

D. Max Smith is a Research Associate with the Rocky Mountain Research Station at the Forestry 

Science Laboratory in Albuquerque, New Mexico. He completed a B.S. degree in Wildlife Biology at 

the University of Montana, Missoula, Montana, and an M.S. degree in Zoology at the University of 

Oklahoma, Norman, Oklahoma.

Steven D. Warren is a Research Ecologist with the Rocky Mountain Research Station at the Shrub 

Sciences Laboratory in Provo, Utah. He completed a B.S. degree in Botany and Range Science 

and an M.S. degree in Wildlife and Range Resources at Brigham Young University, Provo, Utah, 

and a Ph.D. in Watershed Management at Texas A&M University, College Station, Texas.

Deborah M. Finch is a Biological Scientist and Program Manager with the Rocky Mountain 

Research Station at the Forestry Science Laboratory in Albuquerque, New Mexico. She completed 

a B.S. degree in Wildlife Management at Humboldt State University, Arcata, California, an M.S. 

degree in Zoology at Arizona State University, Tempe, Arizona, and a Ph.D. in Zoology and 

Physiology at University of Wyoming, Laramie, Wyoming. 

Acknowledgments

We thank the Intermountain Region of the USDA Forest Service for financial support to 

conduct this assessment. We are grateful to employees of the Intermountain Region’s Regional 

Office for their insights and particularly Mark Bethke for his oversight and support of the project, 

and Jeff Bruggink, Gina Lampman, Mark Muir, and Cynthia Tait for assistance in identifying goals, 

process, reviews, and points of contact on the Salmon-Challis National Forest. We appreciate the 

Salmon-Challis staff, including Bart Gammet, Dave Deschaine, Jeremy Back, and Josh Milligan, 

for supplying data, assisting site visits, and reviewing early drafts of this report. David Hawksworth 

provided research and editorial assistance. 
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Background and Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Definitions and Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Scale of Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Study Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Anthropogenic Changes to Riparian Ecosystems . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Key Ecosystem Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Current Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

 Distribution and Connectivity of Riparian Ecosystems . . . . . . . . . . . . . . . . . . 13

 Distribution of GDEs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

 Surface Water and Groundwater Fluctuations . . . . . . . . . . . . . . . . . . . . . . . . 26

 Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

 Channel and Floodplain Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

 Condition of Spring Runout Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

 Composition and Condition of Riparian Ecosystems . . . . . . . . . . . . . . . . . . . 53

 Composition and Condition of GDEs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Forest-Wide Patterns and Trends . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Data Gaps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

 GDEs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

 Beaver Activity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

 Aquatic Invasives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

 Surface Mines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

 MIM Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

 Monitoring Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

Contents
Appendix A. Distribution of Riparian Ecosystems . . . . . . . . . . . . . . . . . . . . . . . . . 87

Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Land Type Association Summaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Appendix B. Distribution of GDEs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Land Type Association Summaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Appendix C. Surface Water and Groundwater Fluctuations . . . . . . . . . . . . . . . . 109

Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Land Type Association Summaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

Appendix D. Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

Land Type Association Summaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

Appendix E. Channel and Floodplain Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . 132

Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132

Land Type Association Summaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

Appendix F. Condition of Spring Runout Channel . . . . . . . . . . . . . . . . . . . . . . . . 144

Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

Land Type Association Summaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

Appendix G. Composition and Condition of Riparian Ecosystems . . . . . . . . . . 147

Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147

Land Type Association Summaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148

Appendix H. Composition and Condition 

 of Groundwater-Dependent Ecosystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

Land Type Association Summaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

Appendix I. Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

Stressor Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

Indicator Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174

Appendix J. Acronyms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
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U.S. Forest Service RMRS GTR-394. 2019. 1

Introduction

Background 

and Objectives

Definitions and 

Characteristics

We conducted this assessment of riparian, wetland, and groundwaterdependent ecosystems (GDEs) as part of an agreement between the USDA 

Forest Service Intermountain Region (Region 4) and the Rocky Mountain 

Research Station. The objective was to assist with revision of National 

Forest management plans under the 2012 Planning Rule (36 CFR Part 219). 

We designed methods to meet requirements outlined in the rule to complete 

a rapid assessment of ecological integrity that identifies and considers 

existing information and data relevant to the plan area. Ecological integrity 

is “the quality or condition of an ecosystem when its dominant ecological 

characteristics occur within the natural range of variation and can withstand 

and recover from most perturbations imposed by natural environmental 

dynamics or human influence.” The rule specifies that the assessments should 

address drivers and stressors, as well as structure, function, composition, 

and connectivity of terrestrial and aquatic ecosystems. Recognizing that 

ecological systems cross administrative boundaries, the rule uses an “alllands approach” that requires consideration of how conditions outside the 

National Forest influence resources on the Forest and how actions on the 

Forest impact resources beyond the boundary. The assessment was used by 

the Forest to understand ecological conditions under the current plan and to 

identify needs-for-change to be addressed by the updated forest plan. 

We completed this assessment for the Salmon-Challis National Forest 

(SCNF) by synthesizing information obtained through literature review, 

data compilation, and site visits. The first draft of this report was completed 

in September of 2017. We incorporated comments from the Intermountain 

Regional Office and SCNF staff into this final assessment of ecological 

integrity of riparian ecosystems, wetlands, and GDEs. 

Riparian ecosystems occur at the interface of aquatic and terrestrial zones 

and are influenced by dynamics of surface water and groundwater (Gregory 

et al. 1991). Physical, chemical, and biotic interactions between terrestrial 

and aquatic systems shape riparian areas across three dimensions, with 

one dimension extending from the headwaters of a stream to its mouth, the 

second extending from the groundwater zone to the canopy of vegetation, 

and the third dimension extending from the stream bed to the outer extent of 

the floodplain (Stanford and Ward 1988, 1993; Vannote et al. 1980). Drivers 

of riparian structure and function include volume and timing of stream 

flows, watershed geology, channel geomorphology, extent of area inundated 

by surface water, fluctuations in depth to groundwater, evapotranspiration, 

and fluvial influences such as cut and fill alluviation (Gregory et al. 1991; 

Naiman and Decamps 1997; Naiman et al. 2005). Intermittent and perennial 
U.S. Forest Service RMRS GTR-394. 2019. 2

stream channels have surface flows and groundwater connections adequate to 

support riparian vegetation. Ephemeral channels, with surface flows limited 

to brief periods of intense precipitation or seasonal snowmelt runoff and 

little to no connection with the water table, do not typically support riparian 

vegetation (Barrett et al. 1993; Meinzer 1923). 

Groundwater is defined as “all water below the ground surface, including 

water in the saturated and unsaturated zones” (USDA FS 2012a,b,c). With 

this in mind, GDEs are “communities of plants, animals, and other organisms 

whose extent and life processes are dependent on access to or discharge 

of groundwater” (USDA FS 2012a,b). These systems occur where water 

discharges from the aquifer and can strongly influence local and regional 

biodiversity (Murray et al. 2006). On the SCNF, GDEs include springs, fens, 

some streams and rivers, and riparian wetlands along gaining river reaches, 

all of which may provide habitat for rare flora and fauna. In the GDE sections 

of this report, we focus on spring and wetland GDEs, with riparian areas and 

stream segments covered in the other sections. Springs are entirely supported 

by groundwater, while groundwater-dependent wetlands may receive 

additional inputs from surface water. Fens are wetlands supported primarily 

by groundwater with a minimum depth (usually 40 cm) of accumulated peat 

(Bedford and Godwin 2003; Chadde et al. 1998). 
U.S. Forest Service RMRS GTR-394. 2019. 3

Methodology

Scale of Assessment This assessment was completed at two spatial scales: the SCNF plan 

area and land type associations (LTAs), which the Forest uses for ecosystem 

evaluation and planning. Each LTA is a collection of land type units 

distinguished by processes of geology, geomorphology, soils, climate, and 

vegetation. These processes influence the structure and composition of 

vegetation types, including riparian communities (Padgett et al. 1989). In this 

assessment we evaluated riparian systems, wetlands, and GDEs at the scale 

of the LTAs and summarized results for the plan area. 

We conducted this assessment on the 4.2 million-acre SCNF of eastcentral Idaho, which encompasses 32 LTAs with distinct geology, climate, 

hydrology, and management history (SCNF 2004). The LTAs of the Forest 

can be grouped into eight general land covers: mountain slopelands, cryic 

uplands, strongly glaciated lands, glacial troughlands, steep canyonlands, 

dissected foothills, valley bottom, and cryic basinlands (fig. 1). The most 

common land type is mountain slopelands, which comprise 32 percent of the 

SCNF. These areas were formed by streams cutting through bedrock and tend 

to be moderately steep (SCNF 2004). The valleys in this landform are 

v-shaped, narrow, and steep sided. The vegetative communities of the 

mountain slopelands are primarily Douglas-fir (Pseudotsuga menziesii) and 

ponderosa pine (Pinus ponderosa) forests with some xeric grasslands present, 

including bluebunch wheatgrass (Pseudoroegneria spicata) communities. 

Precipitation in these areas can range from 15 to over 30 inches per year 

and snowpack duration is extremely variable depending on the precipitation 

zone, elevation, and aspect. Most streams in the mountain slopelands are 

intermittent or ephemeral. They are typically dominated by riffles and tend to 

have boulder and rubble substrates unless modified by beaver (SCNF 2004).

Cryic, or perennially frozen, uplands make up 28 percent of the 

Forest. These landscapes contain broad high-elevation, gently inclined 

ridges and mountain slopes formed by freeze/thaw cycles (SCNF 2004). 

The vegetation of the uplands includes subalpine fir (Abies lasiocarpa), 

lodgepole pine (Pinus contorta), and whitebark pine (Pinus albicaulis), with 

small patches of Engelmann spruce (Picea engelmannii) and Douglas-fir 

at lower elevations. Some valleys are characterized by abundant riparian 

vegetation. These lands typically receive large amounts of precipitation, 

with the majority falling as snow. Snowpack duration in the uplands ranges 

from average to very long depending on aspect and elevation, making these 

landscapes important sources of sustained water yield for perennial streams 

and groundwater recharge. With high rates of percolation, surface water 

streams are not common. The few streams that form tend to be small with 

fine sediment substrates (SCNF 2004).

Study Area
U.S. Forest Service RMRS GTR-394. 2019. 4

Figure 1—The eight major land types of the Salmon-Challis National Forest. 
U.S. Forest Service RMRS GTR-394. 2019. 5

The third most common land cover is strongly glaciated lands that 

occupy 15 percent of the Forest. These areas are located at high elevations 

and have been highly modified by glaciation (SCNF 2004). Common 

features include cirques, cirque basins, headwalls, high peaks, and ridges 

carved by glaciers. The typical vegetation communities in the cirque basins 

are dense subalpine fir, lodgepole pine, and Engelmann spruce forests, with 

abundant whitebark pine at higher elevations. These high-elevation lands 

receive substantial precipitation, with the average annual amount exceeding 

30 inches and the majority occurring as snow. Snowpack remains until late 

summer in many locations, making these lands the highest water producing 

areas on the Forest. The cirque basins in particular have high water storage 

capacity and are an important source of sustained water yield to lower 

elevation perennial streams. Some of these basins contain small lakes and 

shallow headwater streams dominated by pools and boulder substrates 

(SCNF 2004). 

Steep canyonlands that include deep canyons with steep-sided slopes 

and their valley bottoms make up 8 percent of the SCNF. These areas were 

formed by streams cutting through bedrock, with some narrow valleys where 

active cutting continues, and some wide valley bottoms with meandering 

streams and depositional material (SCNF 2004). Distribution of vegetation 

in the canyonlands is limited by aspect and geology. Forested systems occur 

on north-facing slopes and typically include Engelmann spruce, Douglasfir, and ponderosa pine. The hotter, dryer, southern aspects are characterized 

by bunch grass, sagebrush, mountain mahogany, greenbrush, and other low 

brush communities. This land type is generally adjacent to major streams and 

receives little precipitation. Streams originating in the canyonlands tend to be 

small, high gradient, and ephemeral or intermittent (SCNF 2004). 

Dissected foothills comprise 3 percent of the Forest. These land types 

consist of low relief hills dissected by fluvial action (SCNF 2004). Timber 

cover is limited, with the most common vegetation communities composed 

of sagebrush and grass species. Average annual precipitation in the dissected 

foothills rarely exceeds 20 inches and streams originating in these lands are 

typically ephemeral or intermittent. Valleys are usually u-shaped with rubble 

and gravel substrates and moderate gradients (SCNF 2004). 

A single association, Valley Bottom, occupies 2 percent of the Forest. 

This land type expands across the diverse geologic settings of the SCNF. It 

includes the channels and floodplains of some of the major streams on the 

Forest, including Yankee Fork, Panther Creek, and the Middle Fork, North 

Fork, and main stem of the Salmon River. The SCNF (2004) report lacks a 

comprehensive description of this land type. 

The least common land type on the SCNF is the cryic basinlands, which 

occupy <1 percent of the Forest. These lands consist of subdued and rounded 

ridgetops with dendritic drainage patterns (SCNF 2004). The surfaces were 

formed by frost action and drainage from glaciers at higher elevations. 

The most common vegetation is subalpine fir, with some Douglas-fir and 
U.S. Forest Service RMRS GTR-394. 2019. 6

ponderosa pine found on warmer aspects and sedges (Carex spp.) and willow 

(Salix spp.) located in the valley bottoms. The hottest, southernmost aspects 

are often barren or support occasional grasses. Average annual precipitation 

in these lands ranges from 20 to 25 inches, with approximately half falling 

as snow. Wet meadows that provide high quality beaver habitat and good 

water storage capacity are significant features in the cryic basinlands. In 

these areas the water table is generally near the land surface and these land 

types serve as significant sources of year-round water. The streams that form 

in the cryic basinlands tend to be small, low gradient, and have meandering 

morphologies. The substrate is typically composed of gravel and fine 

sediment due to the depositional nature of the streams. This characteristic 

also makes these streams vulnerable to disturbance that results in headcutting 

and bank erosion (SCNF 2004). 

The first well-documented human population in the area of the SCNF 

was the Lemhi band of the Shoshone Indian tribe. The Shoshone tribe 

constituted the early residents of the Upper Salmon River, above the Middle 

Fork, having occupied the area for 8 millennia or more (fig. 2). The area 

of the Mountain Shoshone was bounded by the Payette River on the west, 

Salmon River on the north, and Bear River Valley and Bruneau River on 

the south. Much of the Great Basin dried during a climatic change between 

11,000 and 7,000 years ago, and much of the higher elevations became 

dominated by open forests and steppe. This changed the way of life of the 

peoples in the Great Basin. The ancestors of the Shoshone tribe, known as the 

Bitterroot Culture, withdrew into the high mountain country of the Salmon 

River, and retained their big game hunting way of life. Their subsistence life 

consisted primarily on seed gathering and hunting of small mammals (Smith 

1969). There is little known about the impacts that the Bitterroot Culture 

and Shoshone tribe had on riparian and wetland ecosystems. However, it is 

likely, as with many indigenous cultures, that they altered their environment, 

responded to climatic changes, and adjusted to times of feast and famine. 

They did not live in romanticized harmony with nature. While the Native 

Americans clearly possessed vast knowledge of their environment, it did 

not prevent occasional overhunting or depletion of resources to the extent 

that their rudimentary tools and small populations allowed (Krech 2000). 

Specific, well-documented descriptions of the effects of the Shoshone 

Indians and their predecessors on riparian and wetland ecosystems of the 

Salmon-Challis Forest, positive or negative, are lacking.

Europeans apparently first entered the area of the SCNF with the arrival 

of the Lewis and Clark Expedition in 1805 (Smith 1969). President Thomas 

Jefferson commissioned the expedition, called the Corps of Discovery, 

and led by Captains Meriwether Lewis and William Clark, shortly after 

the Louisiana Purchase in 1803 to explore and map the newly acquired 

territory, to find a practical route across the western half of the continent, 

and to establish an American presence in the territory before Britain and 

other European powers tried to claim it (Ambrose 1996). The campaign’s 

secondary objectives were scientific and economic, i.e., to study the 

Anthropogenic 

Changes to Riparian 

Ecosystems
U.S. Forest Service RMRS GTR-394. 2019. 7

Figure 2—Pictographs along the Salmon River are indicative of the long history of 

human influence on riparian ecosystems (photo by D.M. Smith, USFS).

area’s plants, animal life, and geography, and to establish trade with local 

Native American tribes. On 12 August 1805, Meriwether Lewis and three 

companions reached the summit of the Continental Divide at Lemhi Pass and 

stepped into what is now the State of Idaho and the SCNF. They were the 

first white men known to enter Idaho. The ridge on which they stood forms 

the Continental Divide between waters of the Atlantic and Pacific oceans.

In the decades following the Lewis and Clark expedition, parties of 

Euro-Americans entered the Intermountain West in increasing numbers to 

establish a fur trade. The removal of beaver from mountain streams is likely 

the earliest influence of Euro-Americans on riparian and wetland ecosystems 

in the SCNF. Beavers and other furbearers had been harvested by Native 

Americans for food and clothing for millennia, but, given the large numbers 
U.S. Forest Service RMRS GTR-394. 2019. 8

of furbearers reported by early Euro-American explorers, it is unlikely that 

intensive trapping occurred in the region until a connection with European 

markets was established in the early 1800s (Chittenden 1902). Uncontrolled 

trapping would continue until the mid to late 1800s, when the fur trade 

became uneconomical and beavers received legal protection (Clements 

1991).

The discovery of gold in California in 1849 brought large numbers of 

settlers to the western part of what would become the United States, and, 

with them, a demand for red meat, which was largely met by sheep (Beck 

1989). Cattle numbers remained limited in much of the western United States 

until the end of the Civil War in 1865, which triggered rapid expansion of 

people and the associated livestock industry. The arrival of the railroad into 

Kansas in 1866 created a means to supply a growing demand for livestock 

shipped to the eastern United States. This period was made famous by the 

large cattle drives, primarily from Texas to railheads in Kansas. The cattle 

industry expanded into the central and northern Great Plains by the early 

1870s. Much of the land used for grazing was public land, and few laws 

existed to regulate its use. Free-range grazing was the norm.

The years 1880–1885 saw a great boom in the numbers of range cattle in 

the West (Stewart 1936). Extensive unregulated grazing caused significant 

widespread degradation of the vegetation composition and density, and, with 

it, the stability of the soil surface. In 1898, the Department of Interior began 

granting grazing permits to try to limit the number of livestock on Federal 

land. In 1905, the U.S. Forest Service was established, and a system of 

grazing allotments was initiated for rangeland under its jurisdiction. Between 

1910 and 1920, a series of laws were established on Forest Service lands 

to further regulate grazing. As the laws were established and enforced, the 

condition of grazed rangelands gradually improved.

Prior to 1862, most land west of the Mississippi river was held as “public 

domain” by the U.S. Government. In an effort to facilitate the movement of 

citizens to the West, Congress passed the Homestead Act of 1862 in which 

160 acres were granted to anyone who lived on the land and cultivated it 

for 5 years. Almost all prime agricultural land was claimed over the next 

two decades. Most ranchers were unable to take advantage of the legislation 

because they typically needed more than 160 acres to raise enough livestock 

to support a family. Land not claimed under the Homestead Act of 1862 was 

considered part of the public domain and was available for use by almost 

anyone for almost any legal activity. Ranchers were content to use the public 

domain because it was free and not susceptible to taxes. Because nobody 

owned the land, nobody was responsible to maintain it, and public domain 

lands were severely abused and overgrazed. The consequence of the public 

domain policy is often referred to as the “Tragedy of the Commons” (Hardin 

1968).

To encourage continued settlement of marginal lands, Congress passed 

the Enlarged Homestead Act of 1909 granting 320 acres to homesteaders 

for farming. In 1916, Congress passed the Stockraising Homestead Act 
U.S. Forest Service RMRS GTR-394. 2019. 9

granting 640 acres to ranchers if they raised at least 50 cows, although the 

General Accounting Office reported that on much of the remaining public 

domain land, due to climatic conditions or degraded condition of the land, 

it would require 160 acres to support a single cow for one month. In 1934, 

Congress passed the Taylor Grazing Act (named for Colorado Congressman 

Edward Taylor) that withdrew all remaining land from the public domain 

and placed it under the jurisdiction of what would become the Bureau of 

Land Management (Hurlburt 1935). Most of the withdrawn land was in a 

deteriorated state, as noted in the 1936 government publication The Western 

Range (Wallace and Silcox 1946). One of the expressed purposes of the 

Taylor Grazing Act was to “...stop injury to the public lands by preventing 

overgrazing and soil deterioration.” Under the Taylor Grazing Act, ranchers 

could obtain long-term leases on public land for the purposes of livestock 

grazing. Stocking rates were established locally by the Bureau of Land 

Management. While some lands continue to be severely overgrazed, there 

has been a slow but generalized trend of improving condition since 1934, 

particularly on lands managed by the Bureau of Land Management and the 

Forest Service.

Because of recognition and regulation, the condition of most lands 

used for grazing has improved since the 1930s. However, some private 

landowners and users of public lands have still not adopted conservative 

grazing strategies to preserve the condition of the land on which they depend. 

Some rangeland continues to be grazed at unsustainable levels that continue 

to damage the resource. Damage can be particularly egregious in riparian and 

wetland ecosystems (Armour et al. 1991; Kauffman and Krueger 1984).

Where populations of wild or domestic ungulates are excessively high 

due to the lack of regulation and control, they may cause unintended and 

undesirable changes in the plant populations, especially if the overgrazing 

occurs over extended periods of time. Managers must bear in mind, however, 

that disturbance is not a new phenomenon. It has always existed in the form 

of natural fire, atypical weather, insect infestations, earthquakes, landslides, 

overgrazing by native ungulates during temporary population expansions, 

and so on. Such disturbances, and their consequences to the ecosystem, are 

natural and not regulatable. Nature has built-in mechanisms that allow for 

natural recovery following disturbance. Even grazing by domestic livestock 

is not necessarily negative, especially where it mimics natural disturbances 

for which natural recovery mechanisms already exist. The effects of 

overgrazing by domestic livestock, which may exceed the normal capacity 

of an ecosystem to recover, has the potential to set the recovery process 

temporarily back to levels unacceptable in terms of aesthetics, near-term 

productivity, and hydrology (Belsky et al. 1999). Hydrological impacts 

may manifest themselves in the form of flooding, gully erosion, and water 

pollution by sediments, livestock fecal material, and urine. These effects, 

however unaesthetic or displeasing, are generally reparable when stocking 

rates are reduced to an acceptable rate.
U.S. Forest Service RMRS GTR-394. 2019. 10

Another cost of overgrazing is facilitation of nonnative invasive 

plants. Nonnative plants may establish and overrun native riparian plant 

communities. Because the nonnative species have no natural control 

measures, there may be no mechanisms to control them in the future. 

Management that prevents the introduction of exotic species is a first-line 

defense that provides a sure solution; early detection and early response is a 

second-line defense (Hulme et al. 2017; Van Dyke 2008). Once established, 

invasive plants may cause a myriad of problems, such as alteration of 

hydrologic dynamics and increased risk of wildfire. Unlike overgrazing, 

there may be no apparent remedy, and the ecosystems are permanently 

impaired. Rush skeletonweed (Chondrilla juncea) and spotted knapweed 

(Centaurea maculosa) are already well-established in the Middle Fork of the 

Salmon River Corridor, and may be beyond control. The establishment of 

such species may displace desirable native species, significantly alter native 

plant community dynamics, interfere with normal hydrology, increase the 

frequency and intensity of wildfires, and alter nutrient cycling. As there are 

no native disease or insect vectors with the evolutionary capability to control 

them, other controls may not be possible.

Though fire is a natural disturbance, the frequency, severity, and extent 

of fires has been influenced by humans prior to and after Euro-American 

settlement (Nowacki et al. 2012). The direct and immediate effects of 

wildfire on riparian and wetland areas are minimal, primarily due to the 

fact such systems are of limited risk or burning due to the elevated moisture 

content of the vegetation. However, postfire conditions following wildfires of 

high severity and size can have deleterious effects on watershed hydrology, 

particularly in upslope areas. The conditions most affected by fire are those 

that are controlled by vegetation and the soils of the watershed. They include 

interception, infiltration, evapotranspiration, soil moisture storage, and 

overland flow of water. Fire can substantially reduce rainfall interception 

by destroying both the vegetation canopy and the organic litter on the soil 

surface, thereby exposing the soil to the erosive forces of raindrop impact 

and subsequent runoff. Fire can reduce infiltration into the soil by forming a 

water-repellent soil layer or by plugging soil pores with fine ash. Percolation 

through the soil may also be reduced. Reduced infiltration and percolation, in 

turn, can increase surface runoff and sedimentation. Increases in streamflow 

also may occur following fire due to the reduced transpiration losses by 

plants. The most effective way to reduce overall watershed damage by high 

severity wildfires is to reduce the accumulation of fuels (DeBano 2009).

The largest and most destructive fire season in the area of the SCNF, and 

possibly the largest in U.S. history, occurred in August of 1910. Rather than 

a single blaze, many smaller fires combined to burn some 3 million acres 

from the Canadian border south to the Salmon River, and east from the area 

of Spokane, Washington, past Missoula, Montana. The conflagration has 

been called the Great Fire of 1910. Records indicate that lightning ignited 

several of the blazes, but many were of anthropogenic origin resulting from 

careless campers, sparks from train engines, loggers clearing private lands, 
U.S. Forest Service RMRS GTR-394. 2019. 11

and fires of settlers and miners (Smith 1969). The flames were driven by 

fierce winds, causing many disparate fires to grow and merge. Occurring 

early after the origin of the U.S. Forest Service, for better or worse, it played 

a large role in defining modern methods and strategies of fighting forest fires 

of the fledgling organization. Fire suppression continued until the end of the 

20th century, followed by a period of increasingly large and severe wildfires 

(Dennison et al. 2014). Large wildfires in ponderosa pine forests have been 

attributed to past suppression and fuel buildup, whereas wildfire patterns in 

higher elevation forests are largely driven by changes in temperature and 

precipitation (Schoennagel et al. 2004). 

To determine whether riparian ecosystems, wetlands, and GDEs were 

within their natural range of variation (NRV), we selected characteristics of 

ecosystem integrity and sustainability: (1) distribution and connectivity of 

riparian ecosystems; (2) distribution of GDEs; (3) surface and groundwater 

fluctuations; (4) water quality; (5) channel and floodplain dynamics; (6) 

condition of spring runout channel; (7) composition and condition of 

riparian ecosystems; and (8) composition and condition of GDEs. These 

key ecosystem characteristics (KECs) were selected in accordance with 

current planning rules (USFS 2015) and included measures of composition, 

structure, function, and connectivity. We reviewed scientific literature and 

agency reports to develop a list of drivers and stressors that influence each 

KEC. We also selected indicators of current condition in relation to the NRV 

that could be evaluated with available data (table 1). We used Pearson’s 

Correlation, which ranges from -1 to +1, to examine the association between 

stressors and indicators. Associations were considered strongly negative if 

Pearson’s r was less than -0.7 and strongly positive if the value was greater 

than +0.7. Weak associations were identified by an r value between +0.3 and 

+0.7 or -0.3 and -0.7. A Pearson’s r value between -0.3 and +0.3 indicated no 

association.

Key Ecosystem 

Characteristics
U.S. Forest Service RMRS GTR-394. 2019. 12

Key ecosystem 

characteristic Drivers Stressors Indicators

Distribution and 

connectivity of riparian 

ecosystems

Surface flows, groundwater 

availability, groundwater 

discharge, beaver activity

Conifer encroachment, 

upland vegetation encroachment, fire suppression, 

diversions, dams, agriculture, 

development, beaver 

removal

Departure of existing vegetation 

from estimate of pre-European 

settlement vegetation coverage, 

conversion from riparian to 

anthropogenic cover; reservoir area

Distribution of GDEs Geologic setting, extent of 

glaciation and glacial history, 

temperature, precipitation

Roads, diversions, dams, 

mining, climate change

Relative density of GDEs, current 

condition and characteristics of 

GDEs

Surface and 

groundwater 

fluctuations

Temperature, precipitation, 

geologic setting, beaver 

activity

Roads, diversions, dams, 

mining, timber harvest, high 

severity fire, insects and 

disease, grazing, climate 

change

Conifer and upland encroachment, 

deviation in winter temperatures, 

deviation in winter precipitation

Water quality Geologic setting, chemistry 

of precipitation, hydrologic 

regime, dissolution of organic 

and mineral substances

Wildfire, agriculture, 

diversions, mining, grazing, 

roads, recreation, loss of 

wetlands and riparian cover

Community tolerance quotient 

for macroinvertebrates, stream 

temperature, median substrate size, 

impaired freshwater systems

Channel and 

floodplain dynamics

Geologic setting, terrain, 

hydrologic regime, large 

woody debris, beaver activity, 

stabilizing vegetation

Grazing, dams, diversions, 

timber harvest, invasive 

species, climate change

Floodplain acres per stream mile, 

sinuosity, bank stability, bank angle, 

frequency of large wood, volume 

of large wood, wildfire disturbance, 

wetland rating

Spring runout channel 

dynamics

Hydrologic regime, 

precipitation regime, geologic 

setting

Grazing, roads, diversions, 

spring development, 

recreation

Condition of bank morphology, 

condition of channel morphology

Composition and 

condition of riparian 

ecosystems

Surface water dynamics, 

groundwater availability, 

geologic setting, beaver 

activity

Wildfire, wildfire suppression, 

insects and disease, invasive 

species, livestock use, wild 

ungulate use, recreation

Conifer and upland encroachment, 

replacement by introduced 

vegetation, native cover, alien 

cover, condition of riparian and 

wetland vegetation, greenline cover, 

effective ground cover, wetland 

rating

Composition and 

condition of GDEs

Water availability, 

geomorphic setting, sediment 

dynamics, thermal activity

Spring development, 

livestock use, wild ungulate 

use, recreational use, 

ditching, channelization, 

droughts, earthquakes

Disturbance to riparian and wetland 

vegetation, soil exposure

Table 1—Drivers, stressors, and indicators measured for assessment of riparian ecosystems, wetlands, and GDEs.
U.S. Forest Service RMRS GTR-394. 2019. 13

Results

Current Conditions Distribution and Connectivity of Riparian Ecosystems

For the purposes of this assessment, we defined riparian ecosystems as 

areas near streams that are influenced by surface water and groundwater and, 

under natural conditions, support plant species and communities that differ 

from upland areas (fig. 3). Distribution of these unique communities is a 

key characteristic because of the physical, hydrological, and biotic services 

they provide to forest landscapes. Essential physical functions include soil 

stabilization, which maintains conditions required for persistence of resident 

and anadromous fishes (Horan et al. 2000; Hubert 2004; Kershner et al. 

2004). Riparian vegetation is also a key component of terrestrial wildlife 

habitat, providing food, cover, and nesting sites for numerous taxa of high 

conservation priority (Atamian et al. 2010; Collins 1977; Graham et al. 

1999). At larger scales, riparian corridors are critical in connecting habitats 

and wildlife populations (Hauer et al. 2016). 

Drivers

Physical and biotic processes influence the distribution and connectivity 

of riparian ecosystems in western landscapes. The lotic riparian ecosystems 

assessed in this report occur along perennial and intermittent streams that 

remain connected to groundwater when surface flows subside (Barrett et 

Figure 3—The riparian vegetation along Morse Creek contrasts sharply with the 

surrounding uplands (photo by D.M. Smith, USFS).
U.S. Forest Service RMRS GTR-394. 2019. 14

al. 1993). Riparian vegetation can occur across unconfined valley bottoms 

if connectivity of floodplains and stream channels are maintained (Brierley 

and Fryirs 2013). At some streams, beaver dams and instream wood slow the 

movement of water and trap sediment to maintain late-season surface flows, 

floodplain connectivity, and substrate for riparian vegetation (Pollock et al. 

2014; Roni et al. 2002).

Stressors

Significant changes to surface flows and vegetation communities have 

occurred throughout the western United States, altering the distribution and 

connectivity of riparian ecosystems (Webb et al. 2007). Dams and diversions 

alter the volume and timing of surface flows, thereby reducing the extent of 

riparian vegetation (Dewine and Cooper 2007). Reservoirs inundate valley 

bottoms, disconnecting riparian corridors. Dams are relatively rare in the 

SCNF, but portions of some streams are diverted for irrigation. Stressors of 

greater importance include development of valley bottoms for municipal 

areas, agriculture, and industry (Jones et al. 2010; MacFarlane et al. 2017). 

Other forms of development, including roads and mines, have the potential 

to decrease extent and connectivity as well. In many areas, removal of beaver 

has resulted in loss of surface flows and stream incision, fragmenting riparian 

corridors in the process (Pollock et al. 2014). 

Indicators

We determined the NRV status of riparian ecosystem distribution in each 

LTA by examining the area available for riparian vegetation, existing riparian 

vegetation cover, riparian vegetation departure, conversion to anthropogenic 

cover, and reservoir area. We used National Hydrography Dataset (NHD) 

flowlines to represent perennial and intermittent stream channels. To compare 

potential space for floodplain communities, we used the USFS Valley 

Confinement Algorithm (VCA) shapefile (Nagel et al. 2014). We used a 

map of the 50-year flood zone (Abood et al. 2012) that represents areas near 

perennial streams, intermittent streams, and valley bottoms that are inundated 

frequently enough to be considered riparian. It is therefore a useful indicator 

of riparian ecosystem extent. To measure coverage of riparian vegetation, we 

created an existing vegetation type (EVT) raster, using data generated by the 

LANDFIRE program (LANDFIRE 2017). We extracted cells classified as 

riparian and calculated total cover of these cells in each LTA. 

We applied the Riparian Condition Assessment Tool (R-CAT), developed 

by MacFarlane et al. (2017), to the LANDFIRE, NHD flowline, and VCA 

data. In addition to the LANDFIRE EVT raster, we obtained a biophysical 

setting (BPS) raster, which displays vegetation types expected to exist in the 

landscape prior to Euro-American alteration. We created polygons of riparian 

ecosystems by adding 30 m buffers to perennial and intermittent flowlines 

and merging these shapefiles with the VCA shapefile. We compared 

proportion of these polygons covered by riparian vegetation in the BPS and 

EVT rasters to calculate an index of riparian vegetation departure (RVD) for 

perennial and intermittent stream segments. We used these results to compare 

potential changes in distribution of riparian vegetation among LTAs. A 
U.S. Forest Service RMRS GTR-394. 2019. 15

departure index of less than 0 indicated increase in vegetation, 0 to 0.1 

represented negligible departure, an index of 0.1 to 0.33 represented minor 

departure, 0.33 to 0.66 represented significant departure, and an index 

greater than 0.66 represented large departure. See Appendix A for additional 

methodology and descriptions of riparian ecosystem distribution within each 

LTA. 

Riparian Ecosystem Distribution on the SCNF

Distribution and connectivity was very high in much of the SCNF. We 

determined that 75 percent of the Forest was within the NRV, 25 percent was 

moderately altered, and less than 1 percent was outside the NRV (fig. 4). 

Dissected foothills in quartzite, located entirely in managed areas, was the 

only LTA considered outside the NRV. 

Figure 4—NRV status of riparian distribution and connectivity on the Salmon-Challis 

National Forest.
U.S. Forest Service RMRS GTR-394. 2019. 16

The LTAs of the SCNF contained a total of 6,367 miles of perennial 

streams and 7,813 miles of intermittent streams. Miles of perennial streams 

ranged from 2 to 876 in the LTAs, with a mean of 199 (table 2). Miles of 

intermittent streams ranged from 0.4 to 1,149 with a mean of 244. Total area 

Table 2—Riparian distribution and connectivity indicators summarized for LTAs. 

Descriptions of LTA characteristics are located in the appendices. Positive RVD index 

scores indicate decrease in riparian vegetation, negative scores indicate an increase. 

Anthropogenic conversion types include roads, mines, and towns. 

Stream miles RVD index

Anthropogenic 

Conversion (%)

Reservoir acres/

Per. stream 

LTA Per. miles Int. Per. Int.

10G 366.3 309.0 0.69 0.73 <1 0

10M 2.3 2.0 0.49 0.68 0 0

10Q 130.5 124.9 0.63 0.72 1.6 0

10S 15.0 25.7 0.86 0.93 1 0

10V 157.2 208.3 0.58 0.57 0 0

20G 560.7 634.4 0.57 0.61 <1 0

20M 3.6 2.8 0.69 0.65 0 0

20Q 530.9 842.3 0.64 0.67 <1 0

20S 38.9 126.8 0.88 0.85 1 0

20V 790.2 1148.6 0.67 0.72 <1 0.03

30G 444.5 284.5 0.29 0.30 <1 0

30M 2.1 2.9 0.34 0.47 0 0

30Q 297.4 522.3 0.52 0.68 0 0.005

30S 23.0 453.4 0.87 0.89 <1 0

30V 429.9 1017.6 0.47 0.60 <1 0

40G 60.5 41.2 -0.27 -0.17 0 0

40Q 10.7 10.6 0.61 0.70 0 0

40V 10.5 6.1 -0.36 -0.46 0 0

50G 441.4 267.4 0.12 0.44 0 0.0005

50M 3.2 0.4 -0.15 0.76 0 0

50Q 122.5 112.7 0.60 0.80 0 0

50S 26.1 85.6 0.79 0.89 0 0

50V 177.0 222.0 0.28 0.47 0 0

60G 298.9 113.2 0.01 0.24 0 0

60M 3.4 10.1 0.80 0.77 0 0

60Q 268.6 219.0 0.70 0.76 <1 0.1

60S 32.1 150.4 0.77 0.87 0 0

60V 136.8 355.8 0.38 0.61 0 0.3

70Q 4.9 38.4 0.87 0.86 11.6 0

70S 27.6 111.4 0.83 0.82 0 0.1

70V 74.2 158.9 0.78 0.90 <1 0.1

VB 876.1 203.9 0.38 0.62 1.4 0.0002
U.S. Forest Service RMRS GTR-394. 2019. 17

of valley bottoms was 30,077 acres in the Forest, ranging from 0 to 13,120 in 

the LTAs, with a mean of 940. Four LTAs, all categorized as mixed geology, 

had no unconfined valley bottoms. All LTAs contained land within the 

50-year flood zone, which covered 4 percent of the Forest. Among LTAs, 

flood zone coverage ranged from 1 percent to 24 percent, with a mean of 5 

percent. There were 45,732 total acres (1 percent of the Forest) of riparian 

vegetation types as mapped by LANDFIRE EVT. Percent cover of riparian 

types varied from 0.1 to 8 percent with a mean of 1 percent. As expected, the 

Valley Bottom LTA had the greatest percent area of riparian cover. Several 

LTAs with mixed and volcanic geology had relatively high cover as well 

(>2 percent).

R-CAT analysis indicated that 22 percent of perennial stream miles 

had increases in riparian vegetation or negligible departure and 72 percent 

had significant or large departure. At intermittent streams, 13 percent of 

miles had increases or negligible departure and 83 percent of miles had 

significant to large departure. Potential natural forms of departure were 

conifer encroachment, upland encroachment, and replacement by barren 

land. Anthropogenic forms of departure involved conversions to crops and 

hay, developed land, and introduced vegetation. All but four LTAs had 

fewer than 0.1 acres of reservoir per stream mile (table 2). Disruptions in 

connectivity were present along highway corridors and in developed areas, 

which included the town of Salmon and the Yankee Fork drainage.

Distribution of GDEs

Distribution of spring and wetland GDEs is a somewhat unusual KEC, 

but knowledge of the location, extent, and arrangement across the landscape 

is necessary for conservation and management of these systems. The 2012 

Planning Rule (36 CFR Part 219) recognizes that groundwater, GDEs, and 

their associated resources are vital to forest health and sustainability, as well 

as local and regional biodiversity. Still, most National Forests have limited 

knowledge of the landscape-scale distribution of GDEs, as well as their 

species compositions and ecosystem processes. This is true for the SCNF. 

This KEC is included to emphasize the need for improved information 

on the location and characteristics of GDEs across the Forest. With better 

understanding, these systems can be more readily acknowledged in forest 

planning activities.

Drivers

Drivers of the distribution of spring and wetland GDEs include 

underlying geology, terrain, and historic land forming processes. The 

geologic units of the Salmon River basin are igneous, sedimentary, and 

metamorphic, but granitic rocks of the Idaho batholith are the most dominant 

(Young and Lewis 1982). Porous geologies allow recharge of groundwater 

and are important drivers of GDE distribution at lower elevations and in 
U.S. Forest Service RMRS GTR-394. 2019. 18

drier areas. On the SCNF, springs form at the contacts, joints, and faults of 

differing geologies. Groundwater reaches the surface by moving through 

low-permeability rock and unmodified fissures or through large cavities. 

In many cases, springs emerge at a fault line scarp (Whiting and Stamm 

1995). Due to their location at faults, spring distribution in this region can 

be influenced by geologic activity. For example, changes in flow patterns, 

including desiccation of GDEs due to altered groundwater flow paths, was 

observed following the Borah Peak Earthquake in 1983 (Wood et al. 1985). 

Fens tend to occur in glacially influenced landforms such as cirques and 

outwash channels (Chadde et al. 1998) and two major types have been 

identified in Idaho: valley peatlands and subalpine peatlands (Bursik 1990). 

Valley fens are rare and form around lakes and ponds at relatively low 

elevations in major river valleys. Subalpine peatlands are more common in 

Idaho and tend to occur along low gradient subalpine streams (Chadde et al. 

1998). 

GDE distribution also is driven by regional climate and local weather 

patterns, particularly annual variation in snowpack and snow water 

equivalent. Their continued existence relies on discharge from groundwater 

sources and recharge to these systems depends on the amount and timing of 

precipitation, evapotranspirative losses, snow cover thickness, snow melt 

characteristics, and land use/land cover (Klove et al. 2013). Areas with high 

precipitation, particularly areas that accumulate snow that melts slowly, are 

important sources of recharge and are influential to water table depth. Typical 

climate patterns that include low humidity and prolonged dry periods on the 

SCNF significantly limit the development of fens and the location of springs 

(Chadde et al. 1998). 

Stressors

GDE distribution is stressed by natural and anthropogenic activities and 

forces that alter hydrologic connectivity, deplete groundwater sources, or 

increase nutrient loads (Chadde et al. 1998). On the SCNF, the most common 

stressors impacting GDE distribution were roads, diversions, and mining. 

The construction of roads alters hillslope contours and adds impervious 

surfaces to landscapes, decreasing potential infiltration and increasing 

surface runoff (Forman and Alexander 1998; Reid and Dunn 1984). Roads 

are also unnatural sources of fine sediment that can obstruct natural flow 

paths between surface and groundwater systems (Forman and Alexander 

1998; Reid and Dunn 1984). Diversions alter the amount and distribution 

of water received by aquatic systems (Winter et al. 1998). Certain mining 

practices can change the distribution of water within aquatic ecosystems 

and the disappearance or movement of springs is an extreme but possible 

result (Waddell et al. 1981). Peatlands in particular are sensitive to pollutants 

from mining or increased nutrient loads from other activities like grazing or 

agriculture (Chadde et al. 1998). 

Lastly, changing climate may be the greatest stressor influencing the 

distribution of springs and GDE wetlands by altering the amount and form 

of precipitation received on the SCNF. According to the USFS Terrestrial 
U.S. Forest Service RMRS GTR-394. 2019. 19

Condition Assessment of National Forest lands, climate exposure on the 

SCNF is considered in moderate to poor condition (Cleland et al. 2017). 

Seasonal temperatures across the Forest have increased in all four seasons, 

causing temperature exposure to be classified as very poor. Precipitation has 

decreased during winter and spring and increased during summer and fall, 

with only the northern half of the Forest considered in good or very good 

condition in terms of precipitation exposure (Cleland et al. 2017).

Spring Distribution on the SCNF

The Spring Stewardship Institute documented 669 springs and seeps 

from the NHD on the Forest (fig. 5). The NHD layer typically underestimates 

the true number of springs and does not provide information on their 

condition. Forest staff completed several proper functioning condition (PFC) 

assessments at springs that were not included in the Spring Stewardship 

database, suggesting there were likely more undocumented springs on the 

Forest. 

Figure 5—Distribution of documented springs occurring on the Salmon-Challis 

National Forest. The data were derived from the Spring Stewardship Institute 

database (http://springstewardshipinstitude.org/) and include all springs from the 

NHD. 
U.S. Forest Service RMRS GTR-394. 2019. 20

The strongest driver of spring distribution appeared to be geologic 

setting, which also interacted with land types in some places. The largest 

spring densities were located in cryic uplands and dissected foothills set 

in quartzite and volcanic geologies (table 3). Approximately 41 percent of 

springs on the Forest were located in the four LTAs associated with these 

geologic settings (30V, 70V, 30Q, 70Q). There were also numerous springs in 

the Valley Bottom LTA. Steep canyonlands had very few springs, regardless 

of underlying geology. Similarly, mountain slopelands had moderate spring 

Table 3—Number of springs and spring density on the SCNF. The data were derived 

from the Spring Stewardship Institute database (http://springstewardshipinstitute.org/) 

and include all springs in the NHD.

LTA LTA Acres # Springs Spring Density (springs/acre)

10G 160844 8 0.00005

10M 791 0 0

10Q 65313 3 0.00005

10S 15055 0 0

10V 104674 9 0.00009

20G 309806 28 0.00009

20M 2172 0 0

20Q 405990 40 0.00010

20S 51784 10 0.00019

20V 599466 96 0.00016

30G 240927 33 0.00014

30M 2276 0 0

30Q 337764 67 0.00020

30S 170838 25 0.00015

30V 433239 167 0.00039

40G 28686 2 0.00007

40Q 7417 0 0

40V 4198 0 0

50G 231089 9 0.00004

50M 1118 0 0

50Q 90513 3 0.00003

50S 36421 3 0.00008

50V 98559 12 0.00012

60G 148007 6 0.00004

60M 13247 1 0.00008

60Q 167729 30 0.00018

60S 103742 8 0.00008

60V 217761 38 0.00017

70Q 9764 2 0.00020

70S 43036 7 0.00016

70V 75725 37 0.00049

VB 101331 25 0.00025
U.S. Forest Service RMRS GTR-394. 2019. 21

densities for all geologies. Spring distribution in cryic uplands depended 

on the geologic setting, with high spring densities observed in volcanic 

and quartzite settings, moderate spring densities observed in sedimentary 

and granitic geologies, and no springs documented in mixed geologic 

areas. There were very few springs located in cryic basinlands or glacial 

troughlands of any geology. Strongly glaciated lands tended to have moderate 

spring densities in all geologic settings and dissected foothill lands were 

associated with high spring densities.

Natural forces were generally the strongest drivers of spring distribution 

and 97 percent of the SCNF was considered within the NRV (fig. 6). For 

the majority of the Forest, distributions of springs within reference areas 

was comparable to managed portions of the Forest. A single LTA, the Valley 

Bottom, was identified as outside the NRV for spring distribution. This LTA 

makes up 2.4 percent of the Forest and was impacted by the cumulative 

Figure 6—NRV status of spring distribution on the Salmon-Challis National Forest.
U.S. Forest Service RMRS GTR-394. 2019. 22

effects of mining, roads, and diversions, resulting in substantially fewer 

springs per acre in managed areas than in reference conditions. Lastly, there 

was insufficient information to evaluate the NRV status for <1 percent of 

the Forest. Most of these LTAs were in mixed geologies and lacked any LTA 

description. 

It was likely that the resistance and resilience of spring distribution to 

disturbances differs across the Forest. Some LTAs, particularly those in 

the southern half of the Forest, had experienced large deviations in winter 

temperature and precipitation during recent years when compared to the 

previous century (Cleland et al. 2017). It appeared that springs on the 

Forest may be especially vulnerable to altered precipitation, as PFC reports 

noted drying and disappearance of springs during prolonged drought. LTAs 

that experienced large climate deviations were likely more vulnerable to 

cumulative effects of additional stressors including roads, mining, and 

diversions. See Appendix B for additional methodology and descriptions of 

spring distribution within each LTA.

Fen Distribution on the SCNF

We used three data sources to examine the distribution of fens on the 

SCNF. The first source was the National Wetlands Inventory (NWI) database. 

NWI typically underestimates the number and acreage of wetlands and we 

believe this to be true on the SCNF. Secondly, we used PFC reports for 

several GDE wetlands, none of which were recorded in NWI. Lastly, fen 

mapping for the SCNF was completed by the Colorado Natural Heritage 

Program (Smith et al. 2017). This report identified potential fens using digital 

aerial photography and topographic maps and assigned each estimated fen a 

confidence value: low confidence, possible fen, or likely fen. 

NWI documented 2,754 palustrine emergent wetlands (PEMBs; potential 

fens) on the Forest with a total acreage of 2,105 (fig. 7). Nearly all the 

GDE wetlands captured by NWI were located in the southern half of the 

SCNF. The PEMB wetlands were generally located in cryic uplands, glacial 

troughlands, and other glaciated terrains in volcanic and granitic geologic 

settings. Smith et al. (2017) identified 3,401 potential fens covering 5,749 

acres, including 385 likely fens (fig. 8). The primary drivers of potential fen 

distribution appeared to be geology, topography, and glacial history, with the 

majority of likely fens located in the Strongly Glaciated Lands in Granite 

LTA. Elevation appeared to strongly influence fen formation, with 62 percent 

of potential fens and 57 percent of likely fens occurring in two elevation 

bands (6,000 to 7,000 feet and 8,000 to 9,000 feet; Smith et al. 2017). 

The Colorado Natural Heritage Program report showed the highest 

densities of potential fens in the southwestern part of the SCNF, particularly 

in the Upper Elk Creek, Swamp Creek-Marsh Creek, and Cape Horn Creek 

watersheds. A large spring and fen complex was identified in the Crane 

Meadow area, as well as the second largest potential fen on the Forest. The 

largest fen on the Forest, Blind Summit Fen, is located in the Swamp CreekMarsh Creek watershed and measures 140 acres within the SCNF boundary 
U.S. Forest Service RMRS GTR-394. 2019. 23

Figure 7—Distribution of palustrine emergent wetlands (PEMBs, potential fens; 

Cowardin et al. 1979) on the Salmon-Challis National Forest. PEMBs were derived 

from the National Wetlands Inventory (NWI) database.

(Smith et al. 2017). This site is nearly 2 miles long and one-third mile wide 

and is composed of quaking mats that are subirrigated by numerous springs 

(fig. 9; Chadde et al. 1998). Smith et al. (2017) also identified three possible 

iron fens in the Iron Bog Creek watershed. These sites are poor valley bottom 

fens located within a dry sagebrush-steppe ecosystem. The Iron Bog system 

formed on poorly drained alluvial material deposited by glaciers and is 

unusual due to its location (Chadde et al. 1998).

We observed large inconsistencies between the three data sources and 

Smith et al. (2017) acknowledged no strong relationship between their results 

and the potential fens mapped by NWI. Both maps provided by the Colorado 
U.S. Forest Service RMRS GTR-394. 2019. 24

Figure 8—Distribution of potential fens on the Salmon-Challis National Forest. 

Potential fens were derived from the Colorado Natural Heritage Program database 

(Smith et al. 2017). 

Natural Heritage Program and NWI are good starting points for field-based 

verification and biological assessment of potential GDE wetlands (Smith et 

al. 2017), but due to the discrepancies in datasets and lack of ground-truthed 

observations, there was insufficient information to evaluate GDE wetland 

distribution in any LTA. See Appendix B for additional methodology and 

descriptions of GDE wetland distribution within each LTA.
U.S. Forest Service RMRS GTR-394. 2019. 25

Figure 9—Blind Summit Fen near Marsh Creek is part of a large wetland complex 

subirrigated by numerous springs (photo by Salmon-Challis National Forest staff).
U.S. Forest Service RMRS GTR-394. 2019. 26

Surface Water and Groundwater Fluctuations

Fluctuations in surface and groundwater levels is a KEC that influences 

the structure, function, and composition of all riparian and freshwater 

systems. A stream’s natural flow regime includes the timing, frequency, 

magnitude, rate of change, and duration of flooding events (Poff et al. 1997). 

High flows are critical natural disturbances (Resh et al. 1988) that maintain 

diverse aquatic and terrestrial habitats, allow for the exchange of material 

and energy between a stream and its floodplain, and recharge hyporheic and 

groundwater systems (Junk et al. 1989; Poff et al. 1997; Stanford et al. 2005). 

During low flows, succession occurs as riparian plants establish and grow 

on recently scoured or deposited alluvium (Stromberg et al. 1991; Whited 

et al. 2007). These base flows are supported by discharge from groundwater 

resources that are maintained by infiltration from rainfall and snowmelt 

(Poff et al. 1997). Depth to groundwater and fluctuations in the level of 

water tables drives distribution, growth, survival, and composition of plant 

communities (Horton et al. 2001; Shafroth et al. 2000; Smith et al. 1998). 

Furthermore, the life histories of many plant and animal species evolved 

with natural water cycles and are dependent on reliable and predictable 

fluctuations (Lytle 2004; Poff et al. 1997; Stanford et al. 2005). 

Flow regimes of GDEs are distinct from surface water systems 

dominated by runoff. The range of discharge from spring and wetland GDEs 

is narrower than the extremes observed in hydrographs that include snowmelt 

(Whiting and Stamm 1995). Examples from eastern Idaho suggest that 

baseflow in GDEs can be 65 percent of bankfull, which is much greater than 

the 10 percent observed in surface water systems. Groundwater-fed systems 

flow at bankfull approximately 20 percent of the time compared to runoff 

systems that reach bankfull 2 to 4 percent of the time. The timing of flows 

is also different, with peak discharge at GDEs occurring in late summer and 

fall (Whiting and Stamm 1995). Overall, the hydrographs of GDE flows are 

muted compared to surface water streams (Whiting and Moog 2001; Whiting 

and Stamm 1995). The timing, reliability, and reduced extremism of GDE 

discharge is important for species that are associated with GDEs and has 

implications for the base flows observed in surface water systems during late 

summer. 

Drivers

Natural flow regimes of groundwater and surface water systems on 

the SCNF are primarily driven by climate, geology, and beaver activity. 

Fluctuations in ground and surface water levels are also influenced by 

the degree of connectivity between a channel and its floodplain (Junk 

et al. 1989), as well as vegetation that slows runoff and consumes water 

throughout the drainage. There are three distinct precipitation zones on 

the Forest and the hydrographs of streams reflect the precipitation zones 

in which they originate (Tennant and Crosby 2009). The dominant form 

of precipitation below 5,000 feet is rain, and streams with headwaters in 

this zone tend to be flashier and more dynamic. Snow dominates above 

8,200 feet and hydrographs of streams that begin in this zone exhibit strong 

snowmelt patterns. Middle elevations, which compose the majority of the 

Salmon River basin, receive mixed precipitation and streams from this zone 
U.S. Forest Service RMRS GTR-394. 2019. 27

show a snowmelt pulse as well as flashy responses to summer thunderstorms 

(Tennant and Crosby 2009). About 50 percent of the precipitation received 

by the Forest falls as snow between October and March and this snowpack is 

the primary source of streamflow throughout the basin (Sridhar et al. 2013). 

For most systems on the SCNF, flooding driven by snowmelt in early spring 

through mid-summer is part of the natural flow regime (IDEQ 2001). 

The hydrologic response of drainages depends on their geology, with 

some settings allowing infiltration to groundwater systems while others 

yield water through shallow subsurface or overland flow (SCNF 2004). 

The SCNF has complex and diverse geologic assemblages that drive these 

patterns across the Forest (Otto et al. 2005). Steep canyonlands tend to 

support ephemeral and intermittent streams with rapid hydrologic responses 

(SCNF 2004). In moderately steep mountain slopelands, most streams are 

intermittent and the hydrologic response can range from slow to very rapid 

depending on slope dissection. The cryic uplands are important sources 

of sustained water yield throughout the year as they allow high rates of 

infiltration and accumulate large amounts of snow (SCNF 2004). The 

hydrologic response of these areas is slow to average and overland flow is 

rare. The high-elevation, historically glaciated lands are the largest sources 

of perennial discharge on the Forest. Additionally, the basins and troughlands 

act as sponges that absorb significant water during snowmelt and release 

it throughout the year. The hydrologic response of these areas is slow and 

overland flow is rare due to the large storage capacity of the basins (SCNF 

2004).

Lastly, dam building by beavers is a driver of natural flow regimes 

on the SCNF. These structures modulate peaks and troughs of the yearly 

hydrograph, particularly when a series of dams exist within a single drainage 

(Rosell et al. 2005). Beaver dams increase the storage capacity of catchments 

by absorbing and retaining water during high flows. Discharge is then 

slowly released and leads to higher base flows during late summer. Beaver 

ponds and their dams enhance the depth, extent, and duration of inundation 

during flooding and elevate the water table during both high and low flows 

(Westbrook et al. 2006). Significant beaver populations within a drainage 

can result in a transition from intermittent to perennial flow and make 

aquatic and riparian ecosystems more resistant and resilient to the effects of 

drought and climate change (Pollock et al. 2014; Rosell et al. 2005). Beavers 

were historically present and remain active on the SCNF, but their extent is 

naturally limited in some locations by high gradient channels (MacFarlane et 

al. 2015; SCNF 2004).

Stressors

Stressors to water fluctuations include activities and forces that alter the 

timing, frequency, magnitude, duration, or rate of change of natural flows or 

that impact the hydrologic connectivity between ground and surface water 

systems. These forces can be natural or anthropogenic. On the SCNF they 

include wildfire, vegetation mortality due to insects and disease, drought, 

dams and diversions, roads and trails, timber harvest, mining, livestock 

grazing, and altered temperature and precipitation regimes (table 4).
U.S. Forest Service RMRS GTR-394. 2019. 28

Table 4—Stressors to groundwater and surface water fluctuations summarized for LTAs. 

10G 0.0004 0.003 0.0010 0.005 0.00011 13 0 2 0.04 7 0.0008 1

10M 0 0 0 0 0 0 0 0 0 0 0 0

10Q 0.0013 0.007 0.0006 0.004 0.00021 56 0 8 0.12 4 0.0007 3

10S 0.0008 0.005 0.0002 0.002 0 100 5 5 0.11 0 0.0007 0

10V 0.0004 0.002 0.0009 0.005 0.00006 35 2 3 0.03 10 0.0005 1

20G 0.0008 0.001 0.0008 0.002 0.00005 21 14 14 0.00 23 0.0003 7

20M 0 0 0.0003 0.004 0 0 0 0 0 7 0.0009 0

20Q 0.0019 0.002 0.0005 0.001 0.00006 57 37 34 0.01 10 0.0004 12

20S 0.0012 0.005 0.0006 0.002 0.00006 93 10 7 0.03 0 0.0006 0

20V 0.0012 0.003 0.0007 0.002 0.00008 75 11 10 0.04 3 0.0002 5

30G 0.0010 0.001 0.0007 0.001 0 32 21 27 0.08 22 0.0004 3

30M 0 0 0.0001 0 0 2 0 0 0 2 0 0

30Q 0.0013 0.002 0.0007 0.002 0.00003 71 50 38 0.01 8 0.0004 4

30S 0.0010 0.008 0.0004 0.003 0.00001 98 7 6 0.00 0 0.0004 1

30V 0.0007 0.001 0.0006 0.002 0.00003 62 13 12 0.00 8 0.0003 1

40G 0.0012 0.002 0.0008 0.001 0.00003 75 74 73 0 8 0.0007 4

40Q 0.0006 0.001 0.0011 0.004 0 100 62 49 0 26 0.0001 6

40V 0.0019 0.001 0.0004 0.002 0 98 88 88 0 0 0.0007 17

50G 0.0004 0.001 0.0008 0.002 0 47 9 14 0.07 12 0.0004 1

50M 0 0 0.0003 0.003 0 0 0 0 0 2 0 0

50Q 0.0003 0.002 0.0006 0.002 0.00001 59 41 42 0 2 0.0003 1

50S 0.0013 0.004 0.0006 0.002 0 97 14 15 0 0 0.0004 2

50V 0.0004 0.001 0.0009 0.002 0 45 19 25 0.06 6 0.0002 1

60G 0.0002 0.000 0.0010 0.001 0.00001 27 5 11 0.00 8 0.0004 0

60M 0 0 0.0000 0 0 86 4 11 0 0 0.0002 0

60Q 0.0010 0.003 0.0009 0.002 0.00004 63 32 21 0.05 2 0.0002 0

60S 0.0003 0.002 0.0002 0.002 0 99 7 13 0 0 0.0003 0

60V 0.0002 0.000 0.0006 0.002 0.00000 61 10 18 0.01 5 0.0002 0

70Q 0.0014 0.003 0.0003 0.000 0.00041 84 3 1 0 0 0.0011 0

70S 0.0018 0.006 0.0002 0.001 0.00005 93 1 1 0 0 0.0003 0

70V 0.0014 0.006 0.0005 0.002 0.00001 95 5 4 0.25 0 0.0001 0

VB 0.0036 0.004 0.0033 0.004 0.00038 60 22 16 0.15 4 0.0008 2

LTA

Road 

miles/LTA 

acre

Road miles/

floodplain 

acre

Trail 

miles/

LTA acre

Trail miles/

floodplain 

acre

Diversion/

LTA acre

LTA 

grazed 

(%)

 LTA 

vegetation 

mortality 

(%)

Floodplain 

vegetation 

mortality 

(%)

Floodplain 

recreation 

sites (%)

 LTA high 

severity 

burn (%)

Mines/

acre

LTA 

timber 

harvest 

(%)
U.S. Forest Service RMRS GTR-394. 2019. 29

Wildfire, vegetation mortality due to insects and disease, and drought 

are natural disturbances to water fluctuations. Depending on severity, fire 

can have major hydrologic implications that include flash flooding or severe 

sedimentation that disrupts connections between ground and surface water 

systems (Doerr et al. 2006; Ice et al. 2004). Widespread vegetation mortality 

due to insects and disease alters water fluctuations by increasing the amount 

of late summer infiltration to groundwater systems (Bearup et al. 2014). 

Prolonged dry and wet periods are linked to predictable changes in water 

table levels throughout the assessment area (Serbina and Miller 2016). Data 

from USGS stream monitoring, for example, shows diminished streamflows 

during drought conditions from 2000 to 2005. While these stressors are 

natural, they can be amplified by anthropogenic activities. A century of 

fire suppression has contributed to an increase in fuel loads that can lead to 

larger, more severe fires (Dennison et al. 2014). Altered temperature and 

precipitation regimes that include warmer temperatures in all four seasons 

and reduced winter precipitation (Cleland et al. 2017) could prolong drought 

on some parts of the Forest. 

Anthropogenic stressors to water fluctuations include diversions, roads 

and trails, timber harvest, mining, and livestock grazing. Diversions disrupt 

natural hydrologic connections and alter the timing, frequency, duration, 

and magnitude of peak and base flows (Winter et al. 1998). Roads and 

trails alter hillslope contours and add impervious surfaces to landscapes, 

decreasing potential infiltration and increasing surface runoff. These features 

can also be unnatural sources of fine sediment that fill lakes, wetlands, 

and stream channels, and that obstruct natural flow paths between surface 

and groundwater systems (Forman and Alexander 1998; Pickering et al. 

2009; Reid and Dunn 1984). The effects of timber harvest on surface and 

groundwater systems depend on how the harvest is managed (Bosch and 

Hewlett 1982). Clear cutting can increase surface runoff and provide a source 

of sediment that disrupts natural surface and groundwater networks (Bosch 

and Hewlett 1982). Mining activity can alter the direction and structure of 

natural flow paths and lead to channel entrenchment, potentially resulting 

in reduced groundwater discharge, different distribution of water within a 

stream, or the disappearance or movement of springs (Bjerklie and LaPerriere 

1985). Lastly, livestock grazing can reduce vegetative cover in the uplands 

and riparian areas, decreasing stability, increasing runoff, and allowing 

down-cutting and entrenchment of streams. Ultimately, this process leads to 

lower water tables and the drying of perennial water sources (Krueper 1993).

Changes in temperature and precipitation influence natural flow regimes 

in numerous ways. Warmer temperatures and altered precipitation regimes 

result in reduced snowpack, earlier snowmelt, and more precipitation in the 

form of rain—all forces that alter the natural timing and magnitude of flows 

(Cayan 1996; Hamlet et al. 2005). Furthermore, warmer temperatures result 

in increased evapotranspiration and altered distribution of plants that draw 

on groundwater sources (Chen et al. 2011; Rind et al. 1990; Weiss et al. 

2009). The average temperatures between 1985 and 2015 of all four seasons 
U.S. Forest Service RMRS GTR-394. 2019. 30

have increased compared to the previous century (Cleland et al. 2017). 

Precipitation has generally decreased during winter and spring and increased 

during summer and fall (Cleland et al. 2017). Natural groundwater and 

surface water fluctuations are strained by these changes in temperature and 

precipitation regimes, and therefore any additional stressors act cumulatively 

(IAP 2016). 

The major stressors of concern on the SCNF included mining, grazing, 

vegetation mortality, diversions, and roads. Mining began in Napias Creek in 

1866 and has since expanded across the Forest, with few creeks not affected 

(Smith 1969). Most of the mines were located within six LTAs. While 

mine density was helpful in predicting impacts to flow regimes, no surface 

mines GIS layer was available to capture effects to floodplains including 

entrenched channels that lower water tables. Like mining, there has been 

a long history of grazing on the Forest. In the earliest years, overgrazing 

occurred due to trespass stock and resulted in serious damage to some 

drainages (Smith 1969). By 1947, rapid runoff caused by overgrazing was 

apparent in limited areas and most watersheds were in satisfactory condition 

(Smith 1969). Vegetation mortality had primarily impacted the northern half 

of the Forest, with eight LTAs having relatively large amounts of affected 

lands. With only 205 diversions scattered across the SCNF, most LTAs had 

relatively low diversion density. The majority of diversions were located 

in lower elevation LTAs including the Valley Bottom, Dissected Foothills, 

and Steep Canyonlands. According to the recent USFS Terrestrial Condition 

Assessment (Cleland et al. 2017), there were slightly more than 4,200 miles 

of roads on the Forest and about 66 percent of these were classified as 

unimproved.

Fires also have a long history of impacts to water fluctuations on the 

SCNF, including the Great Burn in 1910 (Smith 1969). Reports completed 

in response to the Mustang Complex fire highlight the alterations to flow 

regimes that can follow large fires in this region (SCNF 2012). These fires 

burned nearly 250,000 acres in 2012 and generated approximately 45,000 

acres of water-repellent soil. The Burned Area Emergency Assessment 

predicted a reduction in infiltration of 23-37 percent and an increase in 

streamflow by 218-451 percent in the affected watersheds (SCNF 2012). 

Effects of post-fire flooding, such as major channel shifts or reduced bank 

stability have been captured in the watershed monitoring completed by the 

Forest (SCNF 2017).

Indicators

We used conifer and upland encroachment, as well as deviations in 

winter temperature and precipitation, as indicators of the condition of 

water fluctuations in surface water systems (table 5). Altered flow regimes 

are linked to transitions from riparian cover to upland species, including 

conifers (MacFarlane et al. 2017). Encroachment initiates a positive feedback 

loop in which increased upland cover locks landforms in place, alters the 

flow regime by modifying water yield and timing of fluctuations, and 

allows further upland encroachment (Huxman et al. 2005; MacFarlane et 
U.S. Forest Service RMRS GTR-394. 2019. 31

LTA

Winter 

temperature 

deviation (°F)

Winter 

precipitation 

deviation (%)

Intermittent 

streams conifer 

encroachment (%)

Intermittent 

streams upland 

encroachment (%)

Perennial 

streams conifer 

encroachment (%)

Perennial 

streams upland 

encroachment (%)

10G 2.9 -5 51 41 48 30

10M 2.7 4 71 0 58 13

10Q 2.8 0 58 31 64 24

10S 2.8 -9 80 14 57 36

10V 2.9 -8 64 30 65 25

20G 2.9 -5 49 37 59 28

20M 2.9 -3 41 40 69 0

20Q 2.9 0 74 17 74 13

20S 2.9 -9 56 38 42 50

20V 2.9 -9 54 40 54 41

30G 2.9 -5 54 19 46 21

30M 2.9 -5 96 4 64 19

30Q 2.9 -1 75 10 69 9

30S 2.9 -10 74 19 70 21

30V 2.9 -9 59 25 71 21

40G 3.0 1 42 5 54 19

40Q 3.1 -4 65 21 77 13

40V 3.1 0 36 13 33 10

50G 3.0 -9 60 28 54 19

50M 2.9 -13 98 0 27 22

50Q 2.9 -2 73 17 66 9

50S 3.0 -12 75 13 80 16

50V 2.9 -9 73 12 81 8

60G 2.9 -9 31 20 24 13

60M 3.2 -19 77 18 42 53

60Q 3.0 -6 60 26 40 44

60S 3.0 -15 66 22 26 59

60V 3.0 -13 58 15 51 13

70Q 2.9 -2 17 60 30 47

70S 3.1 -17 31 41 21 64

70V 3.0 -11 29 64 32 62

VB 2.9 -7 58 27 57 20

Table 5—Indicators of the condition of groundwater and surface water fluctuations.
U.S. Forest Service RMRS GTR-394. 2019. 32

al. 2017). We used R-CAT (MacFarlane et al. 2017) analysis to determine 

the percentage of intermittent and perennial streams altered by conifer and 

upland encroachment for each LTA and considered these values as indicators 

of water fluctuations. Changes in snowpack due to anthropogenic warming 

have contributed to altered flow regimes throughout the western United 

States (Safeeq et al. 2015). As the primary control on snow accumulation 

is winter temperature (Safeeq et al. 2015), we used deviation in winter 

temperature and precipitation from the USFS Terrestrial Condition 

Assessment (Cleland et al. 2017) as indicators of the current condition of 

water fluctuations in each LTA. 

To evaluate water fluctuations at GDEs, we used PFC reports completed 

by SCNF staff. These assessments included information on whether the GDE 

experienced relatively frequent inundation, whether water fluctuations were 

extreme, and if water supply was sufficient to maintain hydric soils. We 

summarized these reports and used best professional judgment to determine 

the NRV status of water fluctuations at GDEs. 

Surface and Groundwater Fluctuations on the SCNF

Water fluctuations in surface water systems on the SCNF had been 

impacted by multiple interacting stressors. Based on encroachment indicators 

and deviations in winter precipitation and temperature, 10 percent of the 

Forest was within the NRV, 79 percent was moderately altered, and 11 

percent was outside the NRV (fig. 10). Volcanic and granitic geologies 

with cryic or historically glaciated lands tended to be the most resistant 

and resilient to stressors. Surface water systems in sedimentary geologies 

with mountain slopelands and dissected foothills were most vulnerable 

to stressors to the natural flow regime. Like surface water systems, water 

fluctuations at GDEs also appeared to be impacted by stressors on the Forest. 

There was insufficient information to evaluate the NRV status of GDE water 

fluctuations for 84 percent of the Forest (fig. 11). We were able to assess two 

LTAs and both were outside the NRV. It appears that water fluctuations of 

GDEs located in volcanic dissected foothills or mountain slopelands were 

especially vulnerable to stressors.

Overall, it appeared that roads in the floodplain, diversions, mining, 

recreation sites in the floodplain, grazing, and altered temperature and 

precipitation regimes may have influenced surface and groundwater 

fluctuations on the SCNF. There were weak correlations between upland 

encroachment along intermittent streams and floodplain road density, 

diversion density, mine density, and percent of floodplain impacted by 

recreation sites. We also observed weak associations between upland 

encroachment along perennial streams and floodplain road density, winter 

temperature deviation, winter precipitation deviation, and percent of 

floodplain impacted by recreation sites. It appeared that timber harvest and 

vegetation mortality did not have major impacts to water fluctuations on the 

Forest. Nevertheless, they may have interacted with other stressors such as 

roads and grazing.
U.S. Forest Service RMRS GTR-394. 2019. 33

Figure 10—NRV status of water fluctuations in surface water systems on the Salmon-Challis National Forest.
U.S. Forest Service RMRS GTR-394. 2019. 34

Figure 11—NRV status of water fluctuations at GDEs on the Salmon-Challis National Forest.
U.S. Forest Service RMRS GTR-394. 2019. 35

Stressors can have cumulative effects on natural flow regimes. For 

example, livestock grazing was a stressor in all LTAs considered outside 

their NRV. In addition to grazing, winter precipitation had decreased by at 

least 9 percent and winter temperatures had increased by at least 2.9 °F in 

all LTAs considered outside the NRV. Grazing was identified as a stressor in 

two LTAs considered within the NRV (40G and 40V), but these associations 

had experienced no reduction in winter precipitation. These results implied 

that cumulative stressors should be considered during planning and that 

management actions, such as using a rest period to limit grazing impacts, 

may be more successful in certain LTAs.

Our results aligned with many studies that have concluded that there has 

been a marked decline in annual streamflows in the region and throughout 

the western United States (Luce and Holden 2009; Safeeq et al. 2015). 

This trend is likely to continue as modeling for the Salmon River basin 

predicts the gradual advancement in the timing of peak flow associated 

with snowmelt by about 10 days. Furthermore, the VIC model indicates 

that the expected diminished snow water equivalent, reduced soil moisture, 

and increased evapotranspiration imply the potential to trigger drought in 

the basin (Sridhar et al. 2013). The transitional precipitation zones at midelevations will likely be extremely vulnerable to climate change as areas 

where snow accumulates near 0 °C are most sensitive to warming (Safeeq et 

al. 2015). See Appendix C for additional methodology and descriptions of 

groundwater and surface water fluctuations within each LTA. 

Water Quality

Water quality describes the complex biogeochemical interactions that 

occur within aquatic and riparian ecosystems. The ecology of freshwater 

systems depends on inputs of sediment, nutrients, temperature, dissolved 

oxygen, and pH (Bilotta and Brazier 2008; Dauer et al. 2000; Johnston 

1991; Sanchez et al. 2007). These characteristics impact the structure and 

function of streams, lakes, and GDEs in various ways. Furthermore, aquatic 

systems, particularly aquifers and hyporheic zones, provide the fundamental 

ecosystem service of nutrient transformation and biological filtration 

that results in drinking water for numerous communities (Boulton 2005). 

As surface waters become more polluted, sources of good water quality, 

especially groundwater resources, will be important refugia for considerable 

biodiversity and water sources for human consumption.

Drivers

The biogeochemistry of aquatic systems is driven by geology, chemistry 

of precipitation, the length of time water is in contact with certain soil and 

rock types, mixing of cold and thermal water sources, and the dissolution 

of organic and mineral substances from vegetation, soil, and rocks (Yee 

and Souza 1987). These factors influence the concentrations of dissolved 

substances and the temperature of ground and surface water systems. 

The underlying geology of some watersheds naturally contributes certain 

constituents to both surface water systems and GDEs (Domenico and 

Schwartz 1998). As water moves through flow pathways, it comes in contact 
U.S. Forest Service RMRS GTR-394. 2019. 36

with soil particles and bedrock that provide sources of constituents such 

as calcium, sodium, carbonates, and other elements. The length of time in 

contact with geologic formations influences the concentrations and types 

of constituents dissolved in water. Additionally, geology influences total 

dissolved solids through the types of rock present and how it weathers 

(Domenico and Schwartz 1998). The chemistry of precipitation impacts the 

types of minerals and the rates they dissolve in solution (Douglas 1968; Reid 

et al. 1981). Water quality is further influenced by natural leaching of organic 

matter and nutrients from soil (Qualls and Haines 1992), as well as biological 

processes within the riparian zone and aquatic environment that alter the 

chemical composition of water (Hill 1996; Osborne and Kovacic 1993).

Stressors

Stressors to water quality include forces that alter temperature, suspended 

sediments, and the concentrations of nutrients, minerals, or pollutants 

(table 6; Bilotta and Brazier 2008; Dauer et al. 2000; Johnston 1991; Sanchez 

et al. 2007). Concentrations can be altered by increasing their input or 

changing the amount of water in the system (Yee and Souza 1987). Large 

nutrient loads can cause algal blooms that ultimately lead to eutrophication 

(Anderson et al. 2002; Smith et al. 1999). Large inputs of sediments can 

reduce the depth of channels, lakes, and ponds (Einstein 1950) and fine 

sediment can obstruct interstitial spaces that link surface and groundwater 

systems (Richards and Bacon 1994; Wood and Armitage 1997). Shallow 

streams and lakes and systems with diminished groundwater inputs tend to 

have higher water temperature (Poole and Berman 2001). Stream temperature 

can be further increased by the loss of riparian vegetation that shades aquatic 

systems (Poole and Berman 2001). Large inputs of sediment can affect water 

quality by transporting pollutants that threaten municipal water supplies and 

aquatic species. Fine sediments suspended in the water column also limit 

light penetration, leading to reduced primary production and impacts to 

trophic relations (Wood and Armitage 1997).

Stressors to water quality can be generated by natural and anthropogenic 

forces. Wildfires are a natural stressor that can temporarily increase nutrient 

and sediment inputs and remove shade-providing riparian vegetation 

(Shakesby and Doerr 2003; Spencer et al. 2003). Many freshwater 

ecosystems have evolved with regular and frequent fire occurring in their 

watersheds. Historically, aquatic systems with high degrees of connectivity 

and robust species populations were resilient to the temporary effects of fire 

on water quality (Dunham et al. 2007). With fragmentation and extensive 

anthropogenic stressors, refugia for species and functional aquatic systems 

are diminished (Neville et al. 2009).

Anthropogenic factors that influence water quality include burning of 

fossil fuels, agriculture, diversions, mining, roads, recreation, and loss of 

riparian zones. Fossil fuel combustion and high intensity agriculture have 

increased nitrogen deposited from the atmosphere (Carpenter et al. 1998). 

Additionally, runoff from fertilized fields or grazed areas can increase 

nutrient inputs to aquatic systems (Carpenter et al. 1998; Yee and Souza 
U.S. Forest Service RMRS GTR-394. 2019. 37

Table 6—Stressors to and indicators of the condition of water quality in surface water systems on the Salmon-Challis National 

Forest.

Stressors Indicators

LTA

Mines per 

acre

Floodplain 

rec sites (%)

Trail mile per 

floodplain 

acre

Road mile 

per floodplain 

acre

LTA 

grazed 

(%) CTQ D50

Median 

stream 

temp. (°C)

Streams 

impaired 

(%)

Waterbodies 

impaired (%)

10G 0.0008 0.04 0.005 0.003 13 59 0.09 13.4 1.5 0

10M 0 0 0 0 0 - - - 0 0

10Q 0.0007 0.12 0.004 0.007 56 61 0.06 11.4 7.7 0

10S 0.0007 0.11 0.002 0.005 100 60 0.03 10.1 31.1 0

10V 0.0005 0.03 0.005 0.002 35 54 0.05 10.6 1.3 0

20G 0.0003 0 0.002 0.001 21 61 0.08 11.4 0.3 0

20M 0.0009 0 0.004 0 0 - - - 0 0

20Q 0.0004 0.01 0.001 0.002 57 56 0.05 10 2.9 34.6

20S 0.0006 0.03 0.002 0.005 93 63 0.02 12 21.6 21

20V 0.0002 0.04 0.002 0.003 75 61 0.03 10.9 7.1 37.6

30G 0.0004 0.08 0.001 0.001 32 - 0.01 - 0.1 7.1

30M 0 0 0 0 2 - - - 0 0

30Q 0.0004 0.01 0.002 0.002 71 57 0.03 8.1 5.3 15.9

30S 0.0004 0 0.003 0.008 98 - - - 13.4 92.8

30V 0.0003 0 0.002 0.001 62 71 0.01 9.8 6.7 22.6

40G 0.0007 0 0.001 0.002 75 66 0.05 14.8 0 0

40Q 0.0001 0 0.004 0.001 100 - - - 11.3 3.1

40V 0.0007 0 0.002 0.001 98 - - - 0 0

50G 0.0004 0.07 0.002 0.001 47 47 0.04 9.4 0.9 6.2

50M 0 0 0.003 0 0 - - - 0 0

50Q 0.0003 0 0.002 0.002 59 42 0.05 9.3 5.1 38.1

50S 0.0004 0 0.002 0.004 97 - - - 4.8 0

50V 0.0002 0.06 0.002 0.001 45 50 0.05 9.6 2.6 27.7

60G 0.0004 0 0.001 0 27 - - - 0 26.8

60M 0.0002 0 0 0 86 - - - 0 0

60Q 0.0002 0.05 0.002 0.003 63 55 0.04 10.8 4.1 23.3

60S 0.0003 0 0.002 0.002 99 - - - 5.7 7.5

60V 0.0002 0.01 0.002 0 61 - - - 6.7 34.6

70Q 0.0011 0 0 0.003 84 - - - 5.2 0

70S 0.0003 0 0.001 0.006 93 - 0.04 - 18.7 0

70V 0.0001 0.25 0.002 0.006 95 82 0.01 - 7.6 0

VB 0.0008 0.15 0.004 0.004 60 54 0.05 10.5 2.8 11.1
U.S. Forest Service RMRS GTR-394. 2019. 38

1987). Diversions and pumping remove water from the system and can 

increase the concentration of dissolved minerals and solutes (Liu et al. 2003). 

Mining can introduce trace metals as well as increase phosphorus loading 

(Yee and Souza 1987). Roads, particularly those located within floodplains, 

are unnatural sources of sediment and are linked to altered levels of heavy 

metals, salinity, turbidity, and dissolved oxygen (Forman and Alexander 

1998). Recreation areas, including trails and campsites, can increase 

sediment inputs and affect water quality through refuse disposal. Lastly, 

wetlands and riparian zones are very effective at trapping sediments and 

nutrients. In fact, Gilliam (1994) identified these areas as the most important 

factor influencing nonpoint-source pollutants and essential for surface water 

quality protection. Globally, riparian areas are shrinking, with potential 

deleterious effects to water quality (Verhoeven et al. 2006).

Indicators

We used five indicators to determine the NRV status of surface water 

quality of each LTA (table 6): the Community Tolerance Quotient (CTQ) for 

macroinvertebrates, average hourly temperature from July 15–August 31, 

median substrate size (D50s), and the percentages of streams and waterbodies 

classified as impaired by the Idaho Department of Environmental Quality 

(IDEQ). The CTQ is an index developed by Winget and Mangum (1979) that 

has been used frequently by the USFS and the Bureau of Land Management. 

Macroinvertebrate taxa are assigned a tolerance quotient ranging from 2 to 

108, with lower quotients associated with high quality, unpolluted waters and 

higher quotients found in severely polluted waters. The CTQ data have been 

collected by the Pacfish-Infish Biological Opinion Effectiveness Monitoring 

Program (PIBO) since 2003. The PIBO program has also collected the 

average hourly temperature data and the median substrate size (D50) data 

used in our assessment of water quality. Temperature data were available 

from 2005 through 2016 and substrate size data were available from 2001 to 

2016. We used IDEQ spatial data to determine the percentage of stream miles 

and waterbodies classified as impaired within each LTA.

To evaluate the water quality status of GDEs, we used PFC reports 

completed by SCNF staff. These assessments include information on the 

stressors present at each GDE including hydrologic and soil alteration or 

recreation and animal effects. Each report noted if changes in water quality 

were affecting the GDE. We summarized these reports for each LTA and 

used best professional judgment to determine the NRV status of GDE water 

quality.

Water Quality on the Salmon-Challis National Forest

Stressors had impacted water quality on a limited portion of the Forest. 

Based on indicators for surface water systems, 41 percent of the SCNF 

was within the NRV, 40 percent was moderately altered, and 1 percent was 

outside the NRV (fig. 12). There was insufficient information to evaluate 

surface water quality on 18 percent of the Forest. GDEs showed less impact 

to water quality with 14 percent of the Forest within the NRV and 2 percent 

considered to be moderately altered (fig. 13). However, there was insufficient 
U.S. Forest Service RMRS GTR-394. 2019. 39

Figure 12—NRV status of water quality in surface water systems on the Salmon-Challis National Forest.
U.S. Forest Service RMRS GTR-394. 2019. 40

Figure 13—NRV status of water quality at GDEs on the Salmon-Challis National Forest.
U.S. Forest Service RMRS GTR-394. 2019. 41

information to evaluate GDE water quality on 84 percent of the SCNF. 

Geologic settings and landforms had some influence on water quality and the 

resistance or resilience of streams to stressors. Sedimentary land types are 

expected to be more productive than granitic, quartzite, or volcanic (SCNF 

2004). Our results showed they also were potentially more vulnerable to 

changes in water quality, but there was insufficient information to evaluate 

the majority of sedimentary LTAs. Quartzite and granitic settings appeared 

fairly resistant and resilient to water quality stressors and volcanics were 

more sensitive. 

The primary stressors to water quality on the SCNF were grazing and 

roads, with some observed effects from recreation sites within floodplains, 

diversions, and mines. There were weak positive associations between 

grazing pressure, measured as percentage of LTA located within an active 

allotment, and higher CTQ values, smaller median substrate size, and 

increased percentages of impaired stream miles. While roads throughout 

watersheds did not appear to have strong effects, roads within floodplains 

were associated with reduced water quality. LTAs with larger floodplain 

road density tended to have higher CTQ values and a larger percentage 

of impaired stream miles. There was a weak positive association between 

mine density and median stream temperature, diversion density and median 

substrate size, and floodplain recreation sites and greater CTQ values.

Our results were consistent with several IDEQ assessments completed 

for subbasins on the Forest including the Salmon River (Middle)-Panther 

Creek Subbasin (IDEQ 2001), the Salmon River (Upper and Lower Middle 

Forks) Subbasin (IDEQ 2008), the Lemhi River Subbasin (IDEQ 2012), the 

Pahsimeroi River Subbasin (IDEQ 2013), the Little Lost River Subbasin 

(IDEQ 2015), and the Salmon River (Upper) Subbasin (IDEQ 2016). These 

reports consistently document reduced water quality due to thermal loading 

and sediment deposition. Additionally, reports for the Upper Salmon, 

Lemhi, and Pahsimeroi Rivers include E. coli and fecal coliform bacteria 

as concerns. The assessments indicate alteration of streambanks and loss 

of riparian vegetative cover due to grazing as major contributors to high 

stream temperatures and large sediment loads. The reports conclude that 

these systems are responsive to restoration and management practices, 

with improvements observed in the Salmon River (Middle)-Panther Creek, 

Upper Salmon River, and Upper and Lower Middle Fork of the Salmon 

River subbasins. These conclusions support our analysis that shows many 

LTAs moderately altered from the NRV. See Appendix D for additional 

methodology and descriptions of surface and GDE water quality within each 

LTA.

Channel and Floodplain Dynamics

Riparian areas include aquatic and terrestrial habitats dispersed across 

a geomorphological template that is formed by the movement of sediment 

and water within the channel and between the channel and the floodplain 

(Junk et al. 1989; Stanford et al. 2005). The distribution of habitats across 

this template is driven by various patterns and processes operating across 

spatial and temporal scales including flooding, channel avulsion, cut and 
U.S. Forest Service RMRS GTR-394. 2019. 42

fill alluviation, recruitment of large wood, and regeneration of vegetation 

(Stanford et al. 2005). Streamflow in particular is a master variable that 

strongly influences channel and floodplain structure. High flows connect 

the stream to its floodplain, enabling the exchange of organic matter and 

energy (Junk et al. 1989; Poff et al. 1997). They also play an important role 

in the life cycle of many riparian vegetation species by dispersing seeds and 

scouring the channel, resulting in bare substrate needed by seedlings. Low 

flows allow for the establishment and growth of vegetation and successional 

rebuilding (Salo et al. 1986; Stanford et al. 2005; Thomaz et al. 2007). 

Complex floodplains with diverse and highly dynamic aquatic and terrestrial 

habitats are more productive (Junk et al. 1989; Thoms 2003), have higher 

biodiversity (Hauer et al. 2016; Ward et al. 1999), and are more resistant and 

resilient to disturbance (McCluney et al. 2014). 

Drivers

A major driver of channel and floodplain dynamics is the underlying 

geology and surrounding terrain. In the Columbia River basin, catchment 

geology explains a significant amount of variation in channel substrates 

and bank attributes (Al-Chokhachy et al. 2010). Channels draining igneous 

catchments tend to support more undercut and steeper banks and larger 

amounts of fine sediment than those in sedimentary settings (Al-Chokhachy 

et al. 2010). Floodplain structure is further influenced by topography. Very 

steep gradients (fig. 14a) and narrow canyons (fig. 14b) limit floodplain 

development in many parts of the SCNF. Due to the steep slopes in these 

areas, debris slides and avalanches are common natural disturbances to 

channels and floodplains (SCNF 2004). These events alter channel structure 

by depositing large amounts of wood or sediment within channels (Benda et 

al. 2005; Fetherston et al. 1995). In topographies with shallower gradients 

or large meadows, wide valley bottoms with streams meandering through 

depositional material are common (fig. 15; SCNF 2004). Lastly, the 

vegetative communities of the surrounding terrain influence the frequency 

Figure 14—(a) The steep gradient limits development of a floodplain at Perreau Creek. (b) Similarly, the narrow canyon of the 

Middle Fork of the Salmon River also limits the development of a floodplain (photos by D.M. Smith, USFS).

a b
U.S. Forest Service RMRS GTR-394. 2019. 43

Figure 15—Streams with shallower gradients and wider valley bottoms, such as Bear 

Valley Creek, meander through depositional material (photo by D.M. Smith, USFS).

and volume of wood within the channel. Debris create complex floodplains 

by altering water velocity, generating locations of scour and deposition, 

stabilizing streambanks, and creating pool habitats (Gurnell et al. 2002). 

Drainages on the SCNF range from forested to grassland and shrubland, 

naturally creating differing amounts of large wood expected within channels. 

The size and condition of forests near the channel, as well as gradient, 

account for variability in the frequency and volume of large woody debris, 

stream substrate, and channel shape (Al-Chokhachy et al. 2010).

In addition to geology and terrain, flooding is a driver of channel and 

floodplain dynamics on the SCNF. The timing, frequency, duration, and 

magnitude of flood pulses influence the extent and condition of riparian 

zones associated with aquatic habitats (Poff et al. 1997). Most of the 

hydrographs of streams on the Forest are dominated by a strong snowmelt 

signature in early summer, with the exception of some low-elevation streams 

that are highly influenced by summer thunderstorms (Tennant and Crosby 

2009). Approximately 55 percent of streams on the SCNF are intermittent or 

ephemeral, limiting the development of their associated floodplains. 

A final driver of channel and floodplain dynamics is beaver activity. 

Beavers modify stream morphology by cutting wood and building dams that 

effectively trap sediment, create and maintain wetlands, alter the structure 

and dynamics of the riparian zone, and lead to the formation of wide, low 

gradient, alluvial plains as the associated ponds fill with sediment (Gurnell 

et al. 1998; Naiman et al. 1988). These meadows contribute to a step pattern 

along the stream’s longitudinal profile. Additionally, beaver dams slow water 

velocity and create variable substrates throughout the channel. Structures 
U.S. Forest Service RMRS GTR-394. 2019. 44

built by beavers increase the heterogeneity of channel widths and depths 

and the diversity of morphological features. Overall, beaver dams encourage 

stable channels with more complex floodplains (Gurnell et al. 1998; Pringle 

et al. 1988). Because of the stabilizing effects of beaver activity, it is common 

to deliberately introduce beaver during restoration efforts (Gurnell et al. 

1988). In the Columbia River basin in particular, beavers have successfully 

been used to aggrade entrenched channels, raise water tables, and expand 

riparian habitat (Pollock et al. 2007). 

Stressors

Compared to other salmon-bearing basins in the northern Pacific, the 

complexity of floodplains and the quality of stream habitats of the Columbia 

River basin are degraded (Luck et al. 2010). Alterations in the structure 

and function of aquatic and riparian systems within this large basin that 

includes the SCNF have frequently been attributed to stressors from certain 

land management practices, including livestock grazing, road construction, 

agriculture, timber harvest, and mining (Al-Chokhachy et al. 2010; Kershner 

et al. 2004; Kershner and Roper 2010). In addition to these stressors, channel 

and floodplain dynamics on the SCNF are also likely impacted by diversions, 

recreation, invasive species, and altered temperature and precipitation 

regimes.

Livestock grazing is one of the primary stressors to channel and 

floodplain dynamics on the Forest. There are numerous impacts to 

floodplains including trampling banks, over-widening streams, a decrease 

in stabilizing vegetation, and unnatural sediment from trailing (George et 

al. 2002; Thibault et al. 1999). With European settlement of the West came 

overgrazing and the removal of vegetation from landscapes (Rapport and 

Whitford 1999). As protective vegetation was destroyed, runoff became 

more sporadic and large amounts of sediment were introduced to channels 

(Armour et al. 1991; Packer 1953). Systems became out of balance between 

the supplies of water and sediment and streams were not able to clear 

depositional material (Armour et al. 1991). Larger peak flows that resulted 

from the loss of vegetation caused channels to become incised and the water 

table to be lowered. Riparian plants were left in drier soils and ultimately 

replaced by upland species, leading to an overall reduction in the size of 

the floodplain (Belsky et al. 1999). Overgrazing did occur on the SCNF, 

primarily due to trespass stock during the very early days of the Forest 

(Smith 1969). In 2017, approximately 60 percent of the Forest had active 

grazing allotments, and the steep terrain of many LTAs tends to concentrate 

livestock and wildlife to valley bottoms (SCNF 2004). 

Stressors such as road construction, recreation, mining, and wildfire 

can impact channel and floodplain dynamics by altering sediment inputs or 

disrupting the connection between the channel and its floodplain (Bellmore 

et al. 2012; Benda et al. 2003; Forman and Alexander 1998; Jones et al. 

2000; Trombulak and Frissell 2000). In addition to providing an unnatural 

source of fine sediment, roads disrupt floodplain development by confining 

or crossing the stream (fig. 16). Roads that parallel streams often limit 
U.S. Forest Service RMRS GTR-394. 2019. 45

Figure 16—A road paralleling Colson Creek erodes into the channel, disrupting 

natural channel migration and contributing sediment to the channel (photo by 

D.M. Smith, USFS).

movement of the channel and road crossings cause streams to become wider 

and shallower with flattened banks (Forman and Alexander 1998; Jones et 

al. 2000; Trombulak and Frissell 2000). Trails and campgrounds can have 

similar effects by increasing sediment inputs and causing trampling of 

stream banks. Artificial banks built to protect roads and recreation structures 

disconnect the stream from its floodplain and simplify the structure of the 

system (Forman and Alexander 1998; Jones et al. 2000; Trombulak and 

Frissell 2000). Similarly, mining, especially instream placer mining, can 

have negative impacts on channel and floodplain dynamics. This type of 

disturbance is common across the Forest with an extreme example in the 

Yankee Fork drainage. Dredging and other mining activities often reduce 

streams to a single channel and limit channel migration and cut and fill 

alluviation (Bellmore et al. 2012). High severity wildfires increase sediment 

inputs to streams and remove riparian vegetation, further altering channel and 

floodplain dynamics (Benda et al. 2003). 

Activities that alter the natural flow regimes and therefore the 

distribution of floodplain habitats include timber harvest, diversions, invasive 

species, and altered temperature and precipitation regimes. Depending on 

how timber harvest is managed, it may affect floodplain structure (Bosch 

and Hewlett 1982). Clear cuts can increase sedimentation and the timing and 

magnitude of surface runoff. The frequency of landslides usually increases 

following harvest, in turn leading to more debris flows that can alter 

channel morphology and the amount of instream wood (Benda et al. 2005). 

Dams and diversions decrease the magnitude of floods that reshape the 
U.S. Forest Service RMRS GTR-394. 2019. 46

geomorphological template, connect a stream to its floodplain, and transport 

sediment downstream (Winter et al. 1998). Dams can starve systems of 

sediment, resulting in channel incision and coarser substrate (Kondolf 1997). 

Furthermore, regulated reaches have 79 percent less active floodplain areas 

and 3.6 times more inactive floodplain area than comparable unregulated 

reaches (Graf 2006). Regulation reduces floodplain complexity by 37 percent 

and interior western rivers are most susceptible to these changes (Graf 

2006). Certain types of invasive species withdraw more groundwater than 

native riparian vegetation, causing the water table to lower and conditions to 

become drier (Di Tomaso 1998; Ehrenfeld 2003). These invasions can initiate 

a positive feedback loop in which drier conditions facilitate more invasive 

species and an even lower water table, eventually leading to an incised 

channel with no connection to its floodplain and a loss in riparian cover 

(MacFarlane et al. 2017). Lastly, warmer and drier conditions can alter flow 

regimes and reduce inundation that drives floodplain dynamics (Dukes and 

Mooney 2004; Stromberg et al. 2007).

Indicators

We used eight indicators of channel and floodplain dynamics to 

determine the NRV status for each LTA: a ratio of floodplain acres per stream 

mile, sinuosity, bank stability, bank angle, frequency of large wood within the 

channel, volume of large wood within the channel, area within floodplains 

of perennial streams that has been burned with moderate to high severity 

between 1984 and 2014, and a cross section wetland rating. Floodplain acres 

per stream mile was calculated using a map of the 50-year floodplain and 

the NHD flowline GIS layer. The PIBO Effectiveness Monitoring Program 

provided the data for sinuosity, bank stability, bank angle, frequency and 

volume of large wood, and the cross section wetland rating. The area within 

floodplains burned with moderate to high severity was calculated using data 

from the USFS Terrestrial Condition Assessment (Cleland et al. 2017). 

Channel and Floodplain Dynamics on the SCNF

Stressors had moderately impacted channel and floodplain dynamics on 

a large portion of the Forest. Based on indicators of floodplain complexity, 

33 percent of the SCNF was within the NRV and 49 percent was moderately 

altered (fig. 17). There was insufficient information to evaluate the NRV 

status for 18 percent of the Forest. It appears that some geologies and 

landforms were more resistant and resilient to stressors. Channels and 

floodplains in granitic geologies, steep canyonlands, and glacial troughlands 

were generally in the best condition on the Forest. Volcanic and sedimentary 

geologies, mountain slopelands, and cryic uplands appeared more vulnerable 

to stressors that alter channel and floodplain dynamics. 

The primary stressors to channel and floodplain dynamics on the SCNF 

were grazing and roads. We observed weak negative correlations between the 

percentage of the LTA with active grazing and bank stability. When compared 

with the PIBO program’s index of physical habitat integrity, we found the 

index decreased with increased grazing pressure. Active grazing is common 

and extensive across the Forest, with a median of 98.5 percent of LTA 
U.S. Forest Service RMRS GTR-394. 2019. 47

Figure 17—NRV status of channel and floodplain dynamics on the Salmon-Challis National Forest.
U.S. Forest Service RMRS GTR-394. 2019. 48

acreage located within active allotments (SCNF 2017). Roads, particularly 

those within floodplains, had also impacted channel and floodplain dynamics. 

Our results showed a correlation between large floodplain road densities and 

the loss of riparian cover, indicated by upland encroachment at perennial and 

intermittent streams. Furthermore, roads in floodplains were associated with 

reduced frequency of large wood and a more degraded PIBO physical habitat 

index. Finally, we observed reduced physical habitat integrity associated with 

more recreation sites within the floodplain. 

The conditions of stream channels and their floodplains on the SCNF 

are monitored by the PIBO Effectiveness Monitoring Program (Archer and 

Ojala 2015). This program assigns an index of physical habitat integrity that 

is calculated using residual pool depth, percent pools, median substrate size, 

percent of pool tail fines less than 6 mm in diameter, large wood frequency, 

and average bank angle. Our results were consistent with analysis completed 

by this program that shows the overall physical habitat index for managed 

sites is slightly degraded compared to reference sites on the Forest, within the 

ecoregion, and throughout the Columbia River basin. The components of the 

index that are especially skewed from reference conditions on the SCNF are 

median substrate size, wood frequency, and bank angle. The PIBO program 

uses repeated measures to assess the trend of the physical habitat index and 

all its components. On the SCNF, there is a significant downward trend in the 

physical habitat integrity index since 2001 (Archer and Ojala 2015). 

Archer and Ojala (2015) further identify patterns and trends for the 

following subbasins: Middle Salmon-Panther Creek, Lemhi, Little Lost, Big 

Lost, Upper Salmon, Lower Middle Fork Salmon, and the Upper Middle 

Fork Salmon. There were significant downward trends in the overall index of 

streams in the Middle Fork-Panther Creek, Little Lost, Big Lost, and Upper 

Middle Fork subbasins. The most common concerns throughout the basin 

are reduced frequency of large wood, smaller median substrate size, and 

larger percentage of fine sediment in pool tails. Wood frequency significantly 

differs from reference conditions in the Middle Fork-Panther Creek, 

Lemhi, Big Lost, and Upper Salmon subbasins. The median substrate size 

significantly differs from reference conditions in the Lemhi, Little Lost, and 

Upper Salmon subbasins. The percentage of pool tail fines less than 6 mm 

significantly differs from reference conditions in the Lemhi, Upper Salmon, 

and Upper Middle Fork subbasins. These conclusions are somewhat limited, 

however, by small sample sizes within the subbasins.

In addition to the PIBO program, streams and their floodplains on the 

SCNF also are monitored by the SCNF Watershed Program. Like PIBO’s 

physical habitat index, the watershed monitoring program records an 

Aquatic Zone Analysis Rating (AZAR) that is based on qualitative ratings 

of vegetative stream cover, vegetative bank cover, dominant vegetative 

type, bank rock content, dominant bank rock size, bank cutting, instream 

sediment deposition, and ungulate bank damage. Our results were consistent 

with analysis completed by the watershed program, which has identified 50 

monitoring sites of concern. The sites were identified if the percent fines 
U.S. Forest Service RMRS GTR-394. 2019. 49

was greater than 30 percent and/or bank stability was less than 80 percent 

and/or the AZAR rating was less than 70 percent based on the average of 

sampling done between 2012 and 2016. Of these, one site was located in the 

Middle Salmon-Chamberlain; 15 were in the Middle Salmon-Panther; 10 

were in the Upper Salmon; two were in the Lower Middle Fork; one was in 

the Upper Middle Fork; six were in the Lemhi; nine were in the Big Lost; 

and six were in the Little Lost. Overall, the Watershed Monitoring Report 

(SCNF 2017) shows no relationship between the percentage of watershed 

grazed, percentage of watershed burned, or road density within the watershed 

and lower AZAR scores. These conclusions, however, are somewhat limited 

as the dataset lacks reference sites and the monitoring is completed only at 

streams with anadromous and/or resident fish and locations easily accessible 

by foot or vehicle. See Appendix E for additional methodology and 

descriptions of channel and floodplain dynamics within each LTA.

Condition of Spring Runout Channel

Runout channels are “groundwater-fed streams that emerge from springs 

or within groundwater-fed wetlands” (fig. 18; USDA FS 2012). Spring 

runout channels can be distinguished from those dominated by runoff by 

their flow regimes and sediment inputs (Griffiths et al. 2008). It is important 

to assess the condition of these unique downstream portions of springs or 

wetlands because they can support unusual aquatic and wetland biota and 

these features are especially vulnerable to spring development. 

Figure 18—Example of a spring runout channel located in the Copper Basin on the 

Salmon-Challis National Forest (photo by D.M. Smith, USFS).
U.S. Forest Service RMRS GTR-394. 2019. 50

Drivers 

The primary drivers of spring runout channel dynamics are flow regimes 

and sediment inputs (Griffiths et al. 2008; Whiting and Stamm 1995). The 

hydrographs of spring-dominated channels tend to be less variable than 

runoff channels (Whiting and Moog 2001). Sediments in spring channels 

tend to be variable in size with cobbles and boulders generally only present 

at the head of springs. Typically, springflow-dominated channels lack fine 

sediments or algae, indicating that sediments are regularly flushed from the 

system (Whiting and Moog 2001; Whiting and Stamm 1995). The muted 

hydrograph and the limited sediment inputs that are characteristic of springs 

lead to channels with steep banks and dense vegetative cover, armored beds, 

greater sinuosity, weakly developed bars, and lower width to depth ratios 

(Griffiths et al. 2008; Whiting and Moog 2001; Whiting and Stamm 1995).

Stressors

Stressors to the condition of spring runout channels include forces 

or activities that alter spring flow regimes, sediment inputs, or channel 

structure (USDA FS 2012). Diversions, regulation, and spring development 

can alter the amount of flow in the channel as well as the timing or 

magnitude of pulses (Kendy and Bredehoeft 2006; Sophocleous 2002). Road 

construction, recreation, and livestock grazing can increase the sediment 

load and overwhelm the system with sediment that cannot be cleared. These 

activities can also lead to trampling channel banks and shallower channels. 

Runout channels affected by trampling, erosion, entrenchment, ditching, or 

redirection of flow can lead to extreme degradation or the complete absence 

or elimination of a runout channel.

Indicators

To evaluate the dynamics of spring runout channels, we used PFC reports 

completed by SCNF staff. These assessments included information regarding 

the geomorphology and soils at each GDE, including if human-caused mass 

movement or other disturbances affected the site stability, if the runout 

channel was functioning naturally and not entrenched or otherwise altered, 

and whether soils were intact and functional without excessive erosion 

or deposition. We summarized these reports and used best professional 

judgment to determine the condition of spring runout channels. 

Condition of Spring Runout Channel on the SCNF

Stressors have impacted the dynamics of spring runout channels on 

some parts of the Forest. Based on PFC reports, approximately 16 percent of 

the SCNF was outside the NRV for the condition of spring runout channels 

(fig. 19). There was insufficient information to evaluate 84 percent of the 

Forest. We were able to evaluate two LTAs for this KEC: 20V and 70V. 

Both are composed of volcanic geologies that appear to be vulnerable to 

forces that alter runout channels. Grazing was impacting spring channels 

with many reports describing trailing, trampling, and shearing and the 

subsequent erosion and entrenchment of the runout channels (fig. 20). More 

information across the Forest is needed to understand the extent of impacts 

to spring runout channels. See Appendix F for additional methodology and 

descriptions of the condition of spring runout channels within each LTA.
U.S. Forest Service RMRS GTR-394. 2019. 51

Figure 19—NRV status of spring runout channel condition on the Salmon-Challis National Forest.
U.S. Forest Service RMRS GTR-394. 2019. 52

Figure 20—Example of impacts, including trailing, trampling, and shearing imposed 

by cattle on a spring runout channel on the Salmon-Challis National Forest (photo by 

K.P. Driscoll, USFS).
U.S. Forest Service RMRS GTR-394. 2019. 53

Composition and Condition of Riparian Ecosystems

Composition and condition of riparian plant communities exert 

disproportionately large influences on forest resources, given the relatively 

small area of riparian ecosystems. Herbaceous and woody riparian plants 

enhance salmonid habitat by stabilizing soil, creating overhanging banks, 

and shading streams (Beschta 1997; Winward 2000). Cottonwoods and 

other riparian trees are favored roosts, nest sites, and foraging substrates for 

terrestrial wildlife (Smith and Finch 2013, 2016). Anthropogenic changes 

to composition and condition of riparian communities have been linked to 

reduction in quality of aquatic and terrestrial habitat and alteration of stream 

dynamics (Krueper et al. 2003; Pollock et al. 2014; Williams et al. 1999). An 

understanding of riparian communities and their condition is therefore key to 

evaluating ecosystem integrity in the SCNF. 

Classification of Riparian Ecosystems in the SCNF

Classification of riparian ecosystems is essential to evaluating 

composition and condition because expected species, disturbance types, 

and response to disturbances vary among physical settings and biotic 

communities (Gregory et al. 1991). With its varied geology and topography, 

the SCNF has physical characteristics of several geographic provinces 

including the Rocky Mountains, Great Basin, and Columbia Plateau. As 

a result, numerous riparian vegetation communities are present in the 

Forest. Riparian ecosystems also are influenced by a variety of physical and 

biological processes that occur over relatively short time scales and can be 

impacted by anthropogenic activities. Given this complexity and dynamism, 

classification of riparian ecosystems remains a challenge. 

Riparian classification has largely focused on existing plant species or 

communities. A field-based classification of riparian community types was 

developed by USFS Region 4 in the 1980s and was applied to portions of 

Idaho, Utah, and Wyoming (Padgett et al. 1989; Youngblood et al. 1985). 

Similar classification systems were developed for riparian and wetland 

types in Montana (Hansen et al. 1995) and eastern Oregon (Crowe and 

Clausnitzer 1997). Though a community type classification reference does 

not currently exist for the SCNF, we use the general framework as a basis for 

evaluation, as requested by the Forest staff. We lack the data to describe all 

of the riparian community types present in the Forest, so we instead describe 

physiognomic dominance groups, within which community types are nested. 

Classification methods also consider the physical settings of riparian 

ecosystems. Geomorphic variables, such as valley confinement, have 

considerable influence over species composition and susceptibility to 

anthropogenic effects (Carlson 2009; Gregory et al. 1991). Below we 

describe general geomorphic settings of riparian ecosystems in the SCNF, 

along with dominance groups and associated species. 

Conifer and low deciduous tree dominance groups are typically found 

in confined settings, which characterize the majority of the perennial stream 

miles in the Forest (fig. 21). Community types often resemble those of 

adjacent uplands (Gregory et al. 1991). Overstory species include subalpine 
U.S. Forest Service RMRS GTR-394. 2019. 54

fir (Abies lasiocarpa), Engelmann spruce (Picea engelmannii), lodgepole 

pine (Pinus contorta), gray alder (Alnus incana), quaking aspen (Populus 

tremuloides), and black cottonwood (Populus trichocarpa). Understory 

plants include water birch (Betula occidentalis), red osier dogwood (Cornus 

stolonifera), willows (Salix spp.), roses (Rosa spp.), sedges (Carex spp.), 

bluejoint reedgrass (Calamagrostis canadensis), other graminoids, and forbs. 

Ponderosa pine (Pinus ponderosa) and poison ivy (Toxicodendron radicans) 

are dominant species along the Salmon River and its larger tributaries 

(Horton 1972). Conifer-dominated riparian communities are habitat for 

wildlife species, such as the tailed frog (Ascaphus montanus), that occur at 

the interface of stream and terrestrial settings. (Dupuis and Steventon 1999).

Tall deciduous tree dominance groups are present in confined settings 

and unconfined valley bottoms (fig. 22). Quaking aspen and black 

cottonwood typically dominate the canopy. In large floodplains, understory 

species include coyote willow (Salix exigua), slender wheatgrass (Elymus 

trachycaulus), intermediate wheatgrass (Thinopyrum intermedium), Timothygrass (Phleum pratense), bluegrasses (Dactylis spp.), and reed canary grass 

(Phalaris arundinacea). Invasive forbs include knapweed (Centaurea spp.) 

and thistles (Cirsium spp.) (Horton 1972). Migratory and resident wildlife 

rely on these community types throughout the year. Animals of conservation 

concern include Lewis’s woodpecker (Melanerpes lewis) and several species 

of bats (Hollenbeck and Ripple 2008; Holloway and Barclay 2000; Saab and 

Vierling 2001). 

Figure 21—The riparian zone along this confined section of Colson Creek contains 

coniferous and low deciduous tree dominance groups. Stream and vegetation 

dynamics are influenced by instream wood and wildfire (photo by D.M. Smith, USFS).
U.S. Forest Service RMRS GTR-394. 2019. 55

Figure 22—This confined section of South Creek contains low deciduous tree and tall 

deciduous tree dominance groups (photo by Pacfish-Infish Biological Opinion, USFS).

Willow, non-willow shrub, and herbaceous dominance groups often 

co-occur in unconfined valley bottoms associated glacial cirques and midslope alluvial floodplains (figs. 23a,b). These settings are characterized by 

extensive stands of planeleaf willow (Salix planifolia), arctic willow (Salix 

arctica), Geyer’s willow (Salix geyerii), coyote willow, Booth’s willow 

(Salix boothii), and sedges. Also present are rushes (Juncus spp.), tufted hair 

grass (Deschampsia cespitosa), currants (Ribes spp.), shrubby cinquefoil 

(Potentilla fruticose), silver sagebrush (Artemesia cana), and roses. Valley 

Figure 23—(a) This section of Lake Creek is located in a strongly glaciated, unconfined valley bottom. Surface flows and 

vegetation are influenced by several beaver dams. (b) This section of Big Timber Creek flows through a mid-slope unconfined 

valley bottom. Tall willow and herbaceous dominance groups are maintained by beaver ponds (photos by Pacfish-Infish 

Biological Opinion, USFS). 

a b
U.S. Forest Service RMRS GTR-394. 2019. 56

bottoms provide important foraging opportunities for moose (Alces alces), 

elk (Cervus elaphus), and beaver (Collins 1977). Herbaceous dominance 

groups are habitat for small mammals, marshbirds, and their predators 

(Hoffmann and Pattie 1968; Medin and Clary 1990, 1991; Pattie and Verbeek 

1967; Perry 1982). Stands of tall willows are noted as critical nesting habitats 

for a variety of birds, including neotropical migrants (Olechnowski and 

Debinski 2008; Singer et al. 1994). Willow and herbaceous groups also 

contain forage plants that are critical to greater sage-grouse (Centrocercus 

urophasinaus) broods during dry periods of the year (Atamian et al. 2010). 

Stands of willows and herbaceous vegetation are often maintained by beaver 

ponds, which are also habitat for fish, waterbirds, western toads (Anaxyrus 

boreas), Columbia spotted frogs (Rana luteiventris), and other amphibians 

(Arkle et al. 2015; Hossack et al. 2015; McKinstry et al. 2001). 

Drivers 

Composition of riparian ecosystems varies among settings in the SCNF, 

with physical processes acting at multiple scales to determine the riparian 

community types that are present. Elevation, climate, and other features 

of the landscape place constraints on which vegetation communities can 

establish along a given stream segment (Hough-Snee et al. 2015). 

Riparian and wetland ecosystems are also shaped by surface water 

and groundwater dynamics. Growth and survival of phreatophytes, deep 

rooted plants such as cottonwoods and willows, are dependent on stable 

groundwater connections (Bilyeu et al. 2008). These connections are 

maintained by numerous factors including occasional flooding, springs, 

beaver dams, and instream wood (Montgomery et al. 2003; Pollock et al. 

2014; Stromberg 2001). Where present, karst systems influence surface flows 

through storage and transport of groundwater (Godfrey 1985; Mills 1989). 

By raising water tables, beaver dams encourage the establishment of willowand herbaceous-dominated community types (Gibson and Olden 2014; 

Marshall et al. 2013).

A variety of natural disturbances influence composition of riparian 

communities in confined and unconfined settings. Reproduction of 

cottonwoods, willows, and other pioneering species occurs in response 

to valley bottom scour and sediment deposition during years with heavy 

precipitation and spring runoff (Baker 1990; Dykaar and Wigington 2000). 

High severity wildfire results in above-ground mortality of trees and shrubs 

but can encourage establishment of deciduous species through sprouting or 

germination (Dwire and Kauffman 2003; Smith et al. 2009; Wolf et al. 2007). 

Clonal sprouting of willows and cottonwoods is also triggered by flooding, 

beaver activity, and other disturbances (Wilding et al. 2014). 

Stressors

Due to their dynamic nature and high productivity relative to upland 

ecosystems, riparian areas are especially vulnerable to colonization by 

introduced plants (Richardson et al. 2007). Introduced species with potential 

to spread into SCNF riparian areas include cheatgrass (Stipa comata), 

thistles, and other invasive species, forage grasses, and landscaped woody 

species such as Russian olive (Elaeagnus angustifolia). 
U.S. Forest Service RMRS GTR-394. 2019. 57

In coniferous-dominated landscapes, fire maintains natural riparian 

vegetation by preventing encroachment and dominance by conifers and other 

late-successional species (Kleindl et al. 2015). Widespread suppression of 

wildfire has therefore led to changes in riparian composition in landscapes 

adapted to frequent wildfires. In coniferous-dominated riparian community 

types, high severity fire, along with insect and disease outbreaks, can have 

long-term influence on canopy composition. In low-elevation floodplains, 

fire can result in mortality of native deciduous trees and facilitate 

replacement by invasive and upland species (Smith et al. 2009). 

Livestock grazing and wild ungulate herbivory have large impacts on 

vegetation and soil in riparian ecosystems. There are numerous effects from 

cattle grazing including decreases in woody and herbaceous vegetation, 

reduction in bank stability, and soil exposure from trailing (George et 

al. 2002; Thibault et al. 1999). Growth is also affected by wild ungulate 

browsing, beaver herbivory, and flooding behind beaver dams. Removal of 

beaver from watersheds has resulted in stream incision and lowering of water 

tables (Pollock et al. 2014). These changes prompt the loss of willow and 

herbaceous communities and the encroachment of conifers and upland plants 

into valley bottoms (Marshall et al. 2013). Additional anthropogenic stressors 

in the SCNF include direct damage to vegetation and introduction of invasive 

species resulting from recreational use of riparian areas. 

Indicators

We used nine indicators of composition and condition to determine the 

NRV status for each LTA. Spatial indicators were conifer encroachment, 

upland encroachment, replacement of nonnative vegetation (from R-CAT), 

and watershed-scale condition of riparian and wetland vegetation (from 

Watershed Condition Framework). The set of field-sampled indicators 

consisted of five variables: reach native cover, reach alien cover, greenline 

cover, effective ground cover, and wetland rating. We also considered 

qualitative information from the Watershed Monitoring Program and Best 

Management Practices monitoring programs (WMP) of the SCNF and our 

own site visits. 

To obtain indicators of composition and condition from spatial data, we 

applied the Riparian Condition Assessment Tool (R-CAT) to LANDFIRE 

data at perennial streams in the SCNF (MacFarlane et al. 2017). With this 

approach, we compared existing vegetation with expected vegetation to 

estimate changes in riparian cover along streams and in valley bottoms. We 

also examined data from the Watershed Condition Framework (WCF), which 

combines qualitative and quantitative assessments of variables including 

riparian and wetland conditions (Potyondy and Geier 2011). 

Several field measurement protocols, developed to measure riparian 

composition and condition, remain in use in the SCNF. In Winward 

Greenline and Multiple Indicator Monitoring (MIM) protocols, riparian 

community types are identified within floodplain riparian complexes and 

at stream margins, the latter for an indication of bank stability (Burton et 

al. 2008; Winward 2000). The PIBO Effectiveness Monitoring Program 
U.S. Forest Service RMRS GTR-394. 2019. 58

focuses on structure and function of riparian ecosystems and as such does 

not address riparian community types (Kershner et al. 2004). The SCNF 

Watershed Monitoring Program incorporates qualitative measures of riparian 

composition and condition into evaluations of stream sites in managed 

portions of the Forest (SCNF 2017). We included PIBO and WMP results in 

our assessment but were unable to obtain greenline and MIM data. 

Composition and Condition of Riparian Ecosystems in the SCNF

Composition and condition of riparian ecosystems had been moderately 

altered in much of the SCNF. We determined that 35 percent of the Forest 

was within the NRV, 41 percent was moderately altered, and there was 

insufficient information to evaluate 24 percent of the Forest (fig. 24). 

The composition and condition index derived from spatial data was high 

(≥0.9) at 10 LTAs with granitic, volcanic, and mixed geologies. This 

index was low (≤0.60) at seven LTAs, most of which were in sedimentary 

or volcanic geologies. Overall, estimates of conifer encroachment and 

upland encroachment were greater in managed portions of the Forest 

(table 7) and varied among LTAs (table 8). We observed a weak positive 

association between the percentage of the LTA with active grazing and 

Figure 24—NRV status of riparian composition and condition in the Salmon-Challis 

National Forest.
U.S. Forest Service RMRS GTR-394. 2019. 59

LTA

Mean conifer 

encroachment

Mean upland 

encroachment

Mean introduced 

vegetation

Riparian/wetland condition

Poor (%) Fair (%) Good (%)

10G 0.15 0.11 0.03 0 21 79

10M 0.16 0.02 0 0 0 100

10Q 0.21 0.09 0.01 0 55 45

10S 0.21 0.21 <0.01 0 100 0

10V 0.20 0.12 0.02 0 54 46

20G 0.16 0.10 0.02 0 11 89

20M 0.17 0.03 0.03 0 0 100

20Q 0.26 0.06 0.01 0 51 49

20S 0.17 0.19 <0.01 0 93 7

20V 0.19 0.15 0.01 0 74 26

30G 0.10 0.05 <0.01 0 37 63

30M 0.13 0.02 0.01 2 0 98

30Q 0.25 0.04 <0.01 0 75 25

30S 0.25 0.12 0 0 60 40

30V 0.20 0.09 0.01 0 74 26

40G 0.10 0.02 <0.01 0 75 25

40Q 0.19 0.05 0 0 100 0

40V 0.10 0.03 <0.01 0 100 0

50G 0.10 0.04 <0.01 0 61 39

50M 0.04 0.02 0 0 0 100

50Q 0.26 0.04 <0.01 0 63 37

50S 0.25 0.06 0 0 70 30

50V 0.18 0.03 <0.01 0 76 24

60G 0.03 0.01 <0.01 0 50 50

60M 0.13 0.08 0 0 99 1

60Q 0.16 0.14 <0.01 0 80 20

60S 0.10 0.11 0 0 67 33

60V 0.10 0.03 0 0 64 36

70Q 0.23 0.21 <0.01 0 71 28

70S 0.10 0.26 0 0 76 24

70V 0.14 0.24 <0.01 0 53 47

VB 0.18 0.08 0.01 0 69 31

Table 8—Composition and condition indicators derived from spatial data, summarized for LTAs.

Table 7—Composition and condition indicators derived from spatial data on the Salmon-Challis National Forest.

Percent confined

Mean conifer 

encroachment (%)

Mean upland 

encroachment (%)

Mean introduced 

vegetation (%)

Forestwide 9 16 9 1

Managed areas 11 18 10 1

Reference areas 5 13 7 1
U.S. Forest Service RMRS GTR-394. 2019. 60

upland encroachment. There was also a weak positive association between 

upland encroachment and recreation sites in the floodplain. Estimates of 

replacement by introduced species were similar in reference and managed 

areas. LTAs with high percentages of replacement were near the mainstem 

Salmon River and Middle Fork of the Salmon River. We observed a weak 

negative correlation between grazing and replacement by introduced 

vegetation. Percentage of the LTA with high fire hazard had a weak positive 

association with introduced vegetation. Grazing had a positive association 

with percentage of LTA in good riparian and wetland condition, whereas fire 

hazard had a weak negative association. 

Composition and condition indices derived from field data were high 

at five LTAs with granitic or quartzite geologies. Indices were low at seven 

LTAs with sedimentary, quartzite, or volcanic geologies. Of the PIBO 

variables, reach native cover and greenline cover were greater at reference 

sites than at managed sites (table 9). Reach alien cover was greater in 

managed sites. Effective ground cover and wetland index were similar 

between managed and reference sites. Means on field-sample indicators 

varied among LTAs and sampling occasions (table 10). Percentage of LTA 

grazed had a weak negative association with native cover, a weak positive 

association with alien cover, and a weak negative association with greenline 

cover during the first sampling occasion. Percentage of LTA with high fire 

hazard had a weak positive association with native cover during the first 

sampling occasion and a weak positive association with greenline cover 

during the first and most recent sampling occasions. Density of recreation 

sites had a weak negative association with effective ground cover during the 

most recent sampling occasion. Recreation had weak positive associations 

with wetland rating during the first and most recent sampling periods. 

A variety of riparian vegetation dominance groups were present in most 

LTAs. Some communities in these groups had been moderately altered, with 

livestock grazing as a primary stressor. To determine which community types 

were most impacted, analysis of MIM and greenline data is needed, along 

with a reach-scale understanding of factors that include current and historical 

beaver presence, departure from historical fire regimes, and intensity of use 

by livestock and wildlife. See Appendix G for additional methodology and 

descriptions of the composition and condition of riparian ecosystems within 

each LTA.
U.S. Forest Service RMRS GTR-394. 2019. 61

Table 10—Field-sampled composition and condition indicators summarized for LTAs.

LTA

Reach Native Cover (%) Reach Alien Cover (%) GL cover (%) EG Cover (%) Mean Wetland Index

First Recent First Recent First Recent First Recent First Recent

10G 83 81 1 <1 92 90 99 91 46 44

10M -- -- -- -- -- -- -- -- -- --

10Q 82 75 4 1 94 114 97 98 57 58

10S 54 79 9 6 70 89 85 93 34 36

10V 69 73 6 6 87 92 88 93 53 56

20G 162 86 3 1 177 96 88 93 47 51

20M -- -- -- -- -- -- -- -- -- --

20Q 76 82 2 1 88 96 95 95 54 55

20S 73 86 4 4 87 96 86 97 49 41

20V 59 68 5 4 73 80 88 91 53 52

30G 111 64 2 4 145 83 67 83 54 62

30M -- -- -- -- -- -- -- -- -- --

30Q 102 76 1 <1 111 95 99 95 54 50

30S -- -- -- -- -- -- -- -- -- --

30V 54 42 4 3 67 59 90 92 32 27

40G 66 55 <1 2 77 62 73 91 61 51

40Q -- -- -- -- -- -- -- -- -- --

40V -- -- -- -- -- -- -- -- -- --

50G 80 79 4 <1 97 86 88 93 47 54

50M -- -- -- -- -- -- -- -- -- --

50Q 51 54 1 2 67 68 93 91 71 65

50S -- -- -- -- -- -- -- -- -- --

50V 71 72 5 3 79 77 90 94 58 62

60G -- -- -- -- -- -- -- -- -- --

60M -- -- -- -- -- -- -- -- -- --

60Q 58 60 4 4 77 90 88 90 50 45

60S -- -- -- -- -- -- -- -- -- --

60V -- -- -- -- -- -- -- -- -- --

70Q -- -- -- -- -- -- -- -- -- --

70S 87 87 3 4 112 109 98 92 61 54

70V 53 99 5 4 57 92 86 90 76 76

VB 68 70 4 5 79 86 92 92 55 56

Reach native 

cover (%)

Reach alien 

cover (%) GL cover (%) EG Cover (%)

Mean wetland 

index

LTA First Last First Last First Last First Last First Last

Forest-wide 68 71 4 4 82 87 91 92 53 53

Managed areas 67 70 5 4 81 87 90 92 53 52

Reference areas 76 76 1 1 86 84 92 93 52 55

Table 9—Field-sampled composition and condition indicators at the Salmon-Challis National Forest.
U.S. Forest Service RMRS GTR-394. 2019. 62

Composition and Condition of GDEs

The composition and condition of communities associated with GDEs 

reflect environmental conditions and management activities, with different 

types promoting regional biodiversity (Springer and Stevens 2009). The 

surface pools of springs and GDE wetlands provide lentic habitat for plants, 

vertebrates, and other biota (fig. 25). Spring runout channels provide unique 

lotic habitats due to relatively uniform water temperatures and low oxygen 

concentrations (Springer and Stevens 2009). These channels also increase 

connectivity across the landscape for organisms associated with surface 

water systems. Runout channels may connect with streams or may terminate 

to subsurface flow while still supporting aquatic and riparian species. Spring 

mounds, composed of calcareous minerals, peat, and other substrates, 

provide specialized habitat features as well. Karst systems, which facilitate 

movement and discharge of groundwater in many parts of the Forest, also 

host unique floras and faunas (Humphreys 2006). 

GDE wetlands, particularly those with accumulated peat, create 

distinct plant communities with many species limited to these specialized 

environments (Bedford and Godwin 2003; Chadde et al. 1998; USDA FS 

2007, 2012a). Whether GDEs are connected to streams and riparian areas or 

isolated and surrounded by upland vegetation, they provide critical habitat 

and ecosystem services (Cohen et al. 2016). The current composition of 

plants, animals, and other biota must be evaluated to inform management 

decisions (Kreamer et al. 2015) and the condition of vegetation and soils at 

GDEs influence the composition and function of these ecosystems. 

Figure 25—This spring pool and runout channel are part of an extensive GDE near 

the East Fork Big Lost River. Graminoids were grazed by cattle in the fall of 2016 

(photo by D.M. Smith, USFS).
U.S. Forest Service RMRS GTR-394. 2019. 63

Drivers 

Water availability and geomorphic setting are the primary bottom-up 

drivers of GDE composition (Cooper and Merritt 2012; Magee and Kentula 

2005; Stevens and Meretsky 2008). Geology and hydrology interact to shape 

water chemistry, which is a determinant of plant community composition of 

fens (Chimner et al. 2010). Other drivers influencing composition of SCNF 

GDEs include sediment dynamics and thermal activity (Brock 1994). 

Stressors

Springs are among the ecosystems most threatened by anthropogenic 

activities in the western United States (Stevens and Meretsky 2008). They 

have been developed for irrigation and livestock use through headbox 

installation, diversion of flows to troughs, and pond construction. These 

activities alter the composition and condition of GDEs, but in some 

situations, spring-dependent flora and fauna persist (Unmack and Minckley 

2008). 

Wildlife and livestock directly affect spring ecosystems through 

grazing and browsing of vegetation. Grazing and browsing can cause soil 

compaction, hummocking, and headcutting. Thermal springs are popular 

recreation sites in the SCNF and there are numerous human impacts to these 

unique ecosystems. These include vegetation trampling, soil compaction, 

and alteration of the natural runout channels for the creation of soaking 

pools. Natural stressors to spring ecosystems include wildfire, which directly 

impacts plant and animal communities, drought cycles, and geological events 

such as the 1983 Borah Peak Earthquake (Wood et al. 1985). 

In fens and other wetlands, disturbance to soils by ditching, trailing, 

and stream incision can cause drying, resulting in oxidation and degradation 

of peat (Chimner and Cooper 2003). Wetland vegetation and soil are also 

vulnerable to grazing, browsing, and trampling. 

Indicators

To evaluate the composition and condition of GDEs, we used PFC 

reports completed by SCNF staff. These assessments included information 

regarding the vegetation and soils at each GDE, including disturbances 

affecting site stability. We summarized these reports to describe the dominant 

groups and plant species that are present. We used the above data and best 

professional judgment to determine the composition and condition of GDEs 

in each LTA. 

Composition and Condition of GDEs on the SCNF 

Data are too limited to describe differences in composition among the 

many types of GDEs in the SCNF. Review of reports and photographs 

indicate, however, that many GDEs on the Forest contain willow dominated 

community types that include arctic willow (Salix arctica), Booth’s 

willow (Salix boothii), and Geyer’s willow (Salix geyeriana). Fens support 

additional shrubs species such as bog laurel (Kalmia polifolia), western 

Labrador tea (Ledum glandulosum), bog blueberry (Vaccinium occidentale), 

resin birch (Betula glandulosa), and gray alder (Alnus incana) (Chadde et 

al. 1998; Jankovsky-Jones et al. 1999). Herbaceous-dominated community 
U.S. Forest Service RMRS GTR-394. 2019. 64

types are frequent in GDEs as well. Dominant/indicator species include 

water sedge (Carex aquatilis), rushes (Juncus spp.), mosses (Sphagnum

spp.), bluejoint reedgrass (Calamagrostis canadensis), tufted hairgrass 

(Deschampsia cespitosa), few-flowered spike-rush (Eleocharis pauciflora), 

and elk slip marsh marigold (Caltha leptosepala). Introduced vegetation is 

present at several of the GDEs that were surveyed. Nonnative species include 

Kentucky bluegrass (Poa pratense), Timothy-grass (Phleum pratense), and 

other forage grasses. Animal communities were largely undescribed in the 

PFC reports. 

Damage to vegetation and soil from livestock and wild ungulates has 

been documented at spring pools, along channels, and in wetlands. This 

damage includes excessive grazing, browsing of trees and shrubs, and soil 

disturbance. Fences can protect vegetation and soil from livestock but must 

be maintained (fig. 26). Channelization, diversion, and ditching have resulted 

in replacement of wetlands by upland vegetation at several GDEs.

We were able to evaluate two LTAs for this KEC (fig. 27), both of which 

were in volcanic geologies. We determined that composition and condition 

were outside of the NRV at 20V because 15 of 25 GDEs were determined to 

be functions at risk due to livestock impacts, upland encroachment, and other 

stressors. Composition and condition were moderately altered at 70V, where 

10 of 17 GDEs were in properly functioning condition. More information 

across the Forest is needed to understand the extent of impacts to GDE 

condition and composition. See Appendix H for additional methodology and 

descriptions of the composition and condition of GDEs within each LTA.

Figure 26—This hillslope spring in the Twelvemile Creek Drainage was previously 

diverted to the trough in the background. Vegetation and soil at the head of the spring 

have been disturbed by livestock following the collapse of an exclosure fence (photo 

by Salmon-Challis National Forest staff).
U.S. Forest Service RMRS GTR-394. 2019. 65

Figure 27—NRV status of composition and condition of GDEs in the Salmon-Challis National Forest.
U.S. Forest Service RMRS GTR-394. 2019. 66

Forest-Wide 

Patterns and Trends

Summary

Livestock grazing and roads appeared to be the primary stressors to 

riparian ecosystems, wetlands, and GDEs on the Forest. We observed 

negative impacts from these two stressors to many KECs including surface 

and groundwater fluctuations, water quality, channel and floodplain 

dynamics, spring runout channel dynamics, and composition and condition 

of riparian ecosystems and GDEs. We found little evidence that livestock 

grazing had shifted composition and condition outside of the NRV at 

perennial streams. Long-term impacts of grazing may be greater at 

intermittent streams and GDE wetlands.

The secondary stressors present on the SCNF with less substantial 

impacts included diversions, mining, and recreation. We observed negative 

impacts to groundwater and surface water fluctuations from diversions and 

mining, but not to other KECs. Recreation sites within floodplains are also 

associated with alterations to water fluctuations and channel and floodplain 

dynamics. Lastly, we assessed timber harvest, high-severity burns, and 

vegetation mortality as potential stressors to riparian ecosystems, wetlands, 

and GDEs.

In addition to stressors caused by management, patterns in temperature 

and precipitation from 2010 to 2014 have been altered from the patterns of 

the previous century (Cleland et al. 2017). These changes in climate can have 

major impacts on riparian systems and GDEs by shifting the flow regime. 

We found that changes in temperature and precipitation were slightly more 

substantial on the southern half of the Forest. All other stressors were acting 

in addition to altered temperature and precipitation (IAP 2016) and there was 

some correlation between stressors caused by management and changing 

temperature and precipitation regimes. LTAs that had experienced larger 

increases in winter temperature tended to have a larger percentage of land 

within active grazing allotments and LTAs with large reductions in winter 

precipitation were also impacted by vegetation mortality, high fire hazard, 

mining, and timber harvest.

Stressors to riparian ecosystems, wetlands, and GDEs tended to act 

cumulatively (IAP 2016). This is of concern for the SCNF as many LTAs 

had multiple stressors. We have identified livestock grazing, roads, and 

recreation sites within the floodplain, mining, and diversions as the major 

activities linked to degraded riparian areas and GDEs. Many of these 

stressors were correlated, meaning an LTA with impacts from one stressor 

was more likely to be affected by multiple stressors. For example, LTAs with 

a high percentage within active grazing allotments also had greater LTA and 

floodplain road density, more unimproved roads, and larger percentage of 

the LTA impacted by vegetation mortality. LTAs with high road densities 
U.S. Forest Service RMRS GTR-394. 2019. 67

also tended to have more trail miles per acre, higher diversion density, more 

recreation sites within floodplains, more mines, and a larger percentage 

having experienced timber harvest. Lastly, LTAs with high mine density also 

tended to have more diversions. See Appendix I for maps displaying the level 

of stressors and indicators in all LTAs.

GDEs

Existing information on the distribution, composition, and condition 

of GDEs was uneven and often lacking across the Forest. We used the 

NWI and NHD databases to locate springs and groundwater-dependent 

wetlands, but both underestimate the true number on the Forest. Fen and 

bog mapping completed by the Colorado Natural Heritage Program (Smith 

et al. 2017) identified potential fen locations and acreages, but there were 

large discrepancies between their report and the NWI database. We found 

56 GDE assessments completed by SCNF staff, with the majority located in 

two LTAs. There is a need for GDE inventories and more thorough biological 

assessments of spring and GDE wetland resources. Monitoring is needed to 

determine if livestock effects on surface pools, runout channels, fens, and 

other GDE features are carried over from one grazing season to the next. 

Additional Level II spring surveys, incorporating inventories of flora and 

fauna, should be conducted in managed and reference portions of the Forest 

to develop a better understanding of anthropogenic effects on GDEs. The 

NHD spring layer and the Colorado Natural Heritage Program fen database 

serve as frameworks to conduct on-the-ground surveys and assessments.

We used the SSI (http://springstewardshipinstitute.org/) database to 

evaluate distribution of springs on the SCNF. It includes all springs from the 

NHD (USGS 2014), as well as documented GDE locations and information 

from the scientific literature and unpublished reports by governmental 

agencies and non-governmental organizations. The only data for the Forest in 

the SSI database is from the NHD layer. We recommend incorporating data 

collected by the SCNF into the SSI database to preserve valuable field data 

and make information available to wider audiences. 

Beaver Activity

Beaver activity is a driver of many of the KECs assessed in this report 

including water quality, water fluctuations, and channel and floodplain 

dynamics. Current levels of beaver activity were poorly documented in most 

of the perennial channels within the Forest. Robust beaver populations would 

increase the resistance and resilience of freshwater systems to the effects 

of climate change and predicted drought. More information is needed to 

determine if the current population is comparable in size and distribution to 

historic levels and locations. 

Aquatic Invasives

Aquatic invasive species can have major impacts on channel dynamics 

and trophic relations within freshwater ecosystems. According to the USFS 

national dataset, there are no instances of aquatic invasives on the SCNF. 

However, there are several documented cases in the surrounding National 

Data Gaps
U.S. Forest Service RMRS GTR-394. 2019. 68

Forests and throughout Idaho. It is likely that there are aquatic invasive 

species on the Forest and either monitoring has not occurred or the data have 

not been added to the national database. Information on the distribution and 

extent of these species would improve our assessment of channel dynamics 

and are important for planning efforts.

Surface Mines

We found no spatial data capturing the location and extent of surface 

mines on the Forest. There is a long history of mining on the SCNF and 

there are examples of extreme impacts, such as those observed in the Yankee 

Fork drainage. While the locations and impacts of large operations are likely 

known, a GIS layer would improve our assessment of channel dynamics and 

water fluctuations and help identify smaller areas that may need restoration.

MIM Data

There was a substantial number of Multiple Indicator Monitoring (MIM) 

sites located on the Forest. These data offer information on annual grazing 

use and long-term trends that would be valuable for ecosystem assessments 

and planning efforts. The data, however, were not in an accessible format and 

we were unable to use them for this report. A more thorough accounting of 

riparian community types may be assembled from these data. 

Monitoring Sites

We used PIBO and SCNF Watershed Program monitoring sites to 

evaluate many of the KECs in this report. We also evaluated the location of 

MIM sites, despite the lack of data. There were several LTAs on the Forest 

with no or very few monitoring sites. Adding sites or evaluating ecosystems 

using PFC, MIM, and Level II GDE protocols would improve assessments of 

riparian, wetland, and GDE conditions in these LTAs. 
U.S. Forest Service RMRS GTR-394. 2019. 69

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Appendix A—Distribution of Riparian Ecosystems

Methods 	 We scored nine indicators for riparian ecosystem distribution based on

whether they showed evidence of no, moderate, or substantial alteration

from reference conditions in the Frank Church-River of No Return and Jim

McClure-Jerry Peak Wildernesses. If the indicator had little or no alteration

it was given a score of 5; moderate alteration was given a score of 3;

substantial alteration was given a score of 1 (table A1). We scored land type

associations (LTAs) based on mean RVD index among stream segments.

Next, we determined the mean proportion of perennial stream segments with

riparian vegetation replaced by anthropogenic cover (development including

mines, roads, and towns), according to Riparian Condition Assessment

Tool (R-CAT) results. Finally, we calculated total reservoir density for each

LTA. We used the means of the above variables calculated for reference

areas Frank Church-River of No Return Wilderness and Jim McClure-Jerry

Peak Wilderness to inform assignment of LTA means to alteration levels.

The cumulative score for each LTA was divided by the potential total (20

points) to determine a final riparian distribution and connectivity score. We

considered this score and other information in our determination of natural

range of variation (NRV) status.

Indicator

Data 

source

Little or no alteration 

(5 points)

Moderate alteration 

(3 points)

High alteration 

(1 point)

Percent conifer encroachment R-CAT <15 15–20 >20

Percent upland encroachment R-CAT <10 10–15 >15

Percent replacement by introduced vegetation R-CAT <1 1–2 >2

Riparian condition WCF Majority of LTA 

in good condition

Majority of LTA 

in fair condition

Majority of LTA 

in poor condition

Percent reach native cover PIBO >75 50–75 <50

Percent reach alien cover PIBO <1 1–2 >2

Percent greenline cover PIBO >80 70–80 <70

Percent effective ground cover PIBO >90 80–90 <80

Cross-section wetland index PIBO >50 40–50 <40

Table A1—Criteria for assigning riparian distribution and connectivity scores, which were used to calculate an index value for 

each LTA. 
U.S. Forest Service RMRS GTR-394. 2019. 88

Land Type Association 

Summaries

10G—Steep Canyonlands in Granite

	 This LTA had over 360 miles of perennial streams, over 300 miles of

intermittent streams, and 177 unconfined valley bottom acres (<1 percent of

the LTA). The 50-year flood zone covered 5 percent of the LTA and riparian

vegetation types covered 1 percent. Most (60 percent) of the LTA was in

Wilderness. R-CAT analysis indicated that decreases in riparian vegetation

had occurred at perennial and intermittent stream segments. Mean percentage

of floodplain converted to anthropogenic cover was greater than 1 percent at

perennial and intermittent segments. The distribution and connectivity index

was fairly high (80 percent), so we determined that this KEC was within the

NRV.

10M—Steep Canyonlands in Mixed Geology

	 This small LTA contained 4 miles of perennial and intermittent streams,

had no unconfined valley bottom acres, and was entirely within Wilderness.

The 50-year flood zone covered 6 percent of the LTA and riparian vegetation

covered 3 percent. R-CAT analysis indicated that decreases in riparian

vegetation had occurred at perennial and intermittent stream segments.

Mean percentage of floodplain converted to anthropogenic cover was less

than 1 percent at perennial and intermittent segments. The distribution and

connectivity index was fairly high (80 percent), so we determined that this

KEC was within the NRV.

10Q—Steep Canyonlands in Quartzite

	 The LTA had over 130 miles of perennial streams, 125 miles of

intermittent streams, and 159 unconfined valley bottom acres (<1 percent of

the LTA). The 50-year flood zone covered 5 percent of the LTA and riparian

vegetation covered 1 percent. Most of the LTA was in managed areas

(82 percent). R-CAT analysis indicated that decreases in riparian vegetation

had occurred at perennial and intermittent stream segments. Mean percentage

of floodplain converted to anthropogenic cover was greater than 1 percent

at perennial and intermittent segments. The distribution and connectivity

index was low (52 percent) because of replacement by introduced vegetation

and developed land. The distribution and connectivity index was fair

(70 percent), so we determined that this KEC was moderately altered from

the NRV.

10S—Steep Canyonlands in Sedimentary Bedrock

	 This LTA had 15 miles of perennial streams, over 25 miles of intermittent

streams, and 112 unconfined valley bottom acres (1 percent of the LTA).

The 50-year flood zone covered 4 percent of the LTA and riparian vegetation

covered 1 percent. The LTA was entirely in managed areas. R-CAT analysis

indicated that decreases in riparian vegetation had occurred at perennial and

intermittent stream segments. Mean percentage of floodplain converted to

anthropogenic cover was 1 percent at perennial segments and less than

1 percent at intermittent segments. The distribution and connectivity index

was fair (60 percent), so we determined that this KEC was moderately 

altered from the NRV.
U.S. Forest Service RMRS GTR-394. 2019. 89

10V—Steep Canyonlands in Volcanics

	 This LTA had over 150 miles of perennial streams, over 200 miles of

intermittent streams, and 237 unconfined valley bottoms acres (<1 percent

of the LTA). The 50-year flood zone covered 4 percent of the LTA and

riparian vegetation covered 2 percent. Most (66 percent) of the LTA was in

Wilderness. There were 27 acres of reservoirs, or 0.03 acres per perennial

stream mile. R-CAT analysis indicated that decreases in riparian vegetation

had occurred at perennial and intermittent stream segments. Mean percentage

of floodplain converted to anthropogenic cover was greater than 1 percent at

perennial segments and 1 percent at intermittent segments. The distribution

and connectivity index was fairly high (80 percent), so we determined that

this KEC was within the NRV.

20G—Mountain Slopelands in Granite

	 This LTA had over 560 miles of perennial streams, over 630 miles of

intermittent streams, and 168 unconfined valley bottom acres (<1 percent

of the LTA). The 50-year flood zone covered 4 percent of the LTA and

riparian vegetation covered 2 percent. Most (56 percent) of the LTA was in

Wilderness. R-CAT analysis indicated that decreases in riparian vegetation

had occurred at perennial and intermittent stream segments. Mean percentage

of floodplain converted to anthropogenic cover was greater than 1 percent at

perennial and intermittent segments. The distribution and connectivity index

was fairly high (80 percent), so we determined that this KEC was within the

NRV.

20M—Mountain Slopelands in Mixed Geology 

	 This wilderness LTA had over 3 miles of perennial streams, 3 miles of

intermittent streams, and no unconfined valley bottom acres. The 50-year

flood zone covered 3 percent of the LTA and riparian vegetation covered

1 percent. R-CAT analysis indicated that decreases in riparian vegetation had

occurred at perennial and intermittent stream segments. Mean percentage

of floodplain converted to anthropogenic cover was greater than 1 percent

at perennial segments and greater than 5 percent at intermittent segments.

The distribution and connectivity index was fairly high (80 percent), so we

determined that this KEC was within the NRV.

20Q—Mountain Slopelands in Quartzite

	 This LTA had 530 miles of perennial streams, over 840 miles of

intermittent streams, and 303 unconfined valley bottom acres (<1 percent of

the LTA). The 50-year flood zone covered 4 percent of the LTA and riparian

vegetation covered 1 percent. Most (83 percent) of the LTA was in managed

areas. R-CAT analysis indicated that decreases in riparian vegetation had

occurred at perennial and intermittent stream segments. Mean percentage of

floodplain converted to anthropogenic cover was 1 percent at perennial and

intermittent segments. The distribution and connectivity index was fairly

high (80 percent), so we determined that this KEC was within the NRV.
U.S. Forest Service RMRS GTR-394. 2019. 90

20S—Mountain Slopelands in Sedimentary Bedrock

	 This LTA had over 30 miles of perennial streams, over 120 miles of

intermittent streams, and 577 unconfined valley bottom acres (1 percent of

the LTA). The 50-year flood zone covered 5 percent of the LTA and riparian

vegetation covered 1 percent. Most (98 percent) of the LTA was in managed

areas. R-CAT analysis indicated that decreases in riparian vegetation had

occurred at perennial and intermittent stream segments. Mean percentage of

floodplain converted to anthropogenic cover was greater than 2 percent at

perennial and less than 1 percent at intermittent segments. The distribution

and connectivity index was fair (70 percent), so we determined that this KEC

was moderately altered from the NRV.

20V—Mountain Slopelands in Volcanics

	 This largest of LTAs had 790 miles of perennial streams, over 1,140

miles of intermittent streams, and 1,658 unconfined valley bottom acres (<1

percent of the LTA). The 50-year flood zone covered 4 percent of the LTA

and riparian vegetation covered 1 percent. Most (68 percent) of the LTA

was in managed areas. R-CAT analysis indicated that decreases in riparian

vegetation had occurred at perennial and intermittent stream segments.

Mean percentage of floodplain converted to anthropogenic cover was greater

than 1 percent at perennial segments and 1 percent intermittent segments.

The distribution and connectivity index was fairly high (80 percent), so we

determined that this KEC was within the NRV.

30G—Cryic Uplands in Granite

	 This LTA had over 440 miles of perennial streams, over 280 miles of

intermittent streams, and 564 unconfined valley bottom acres (< 1 percent of

the LTA). The 50-year flood zone covered 3 percent of the LTA and riparian

vegetation covered 1 percent. Most (54 percent) of the LTA was in managed

areas. R-CAT analysis indicated that decreases in riparian vegetation had

occurred at perennial and intermittent stream segments. Mean percentage

of floodplain converted to anthropogenic cover was less than 1 percent at

perennial and intermittent segments. The distribution and connectivity index

was high (100 percent), so we determined that this KEC was within the NRV.

30M—Cryic Uplands in Mixed Geology

	 This LTA had 2 miles of perennial streams, 3 miles of intermittent

streams, and no unconfined valley bottom acres. The 50-year flood zone

covered 2 percent of the LTA and riparian vegetation covered 1 percent.

Nearly all of the LTA (>99 percent) was in Wilderness. R-CAT analysis

indicated that decreases in riparian vegetation had occurred at perennial and

intermittent stream segments. Mean percentage of floodplain converted to

anthropogenic cover was 1 percent at perennial segments and 0 percent at

intermittent segments. The distribution and connectivity index was high

(90 percent), so we determined that this KEC was within the NRV.
U.S. Forest Service RMRS GTR-394. 2019. 91

30Q—Cryic Uplands in Quartzite

	 This LTA had nearly 300 miles of perennial streams, over 520 miles of

intermittent streams, and 262 unconfined valley bottom acres (0.1 percent of

the LTA). The 50-year flood zone covered 3 percent of the LTA and riparian

vegetation covered less than 1 percent. Most (95 percent) of the LTA was in

managed areas. There was 1 acre of reservoirs, or 0.005 acres per perennial

stream mile. R-CAT analysis indicated that decreases in riparian vegetation

had occurred at perennial and intermittent stream segments. Mean percentage

of floodplain converted to anthropogenic cover was less than 1 percent at

perennial and intermittent segments. The distribution and connectivity index

was fairly high (80 percent), so we determined that this KEC was within the

NRV.

30S—Cryic Uplands in Sedimentary Bedrock

	 This LTA was entirely in managed areas, with over 20 miles of perennial

streams, over 450 miles of intermittent streams, and 181 unconfined valley

bottom acres (<1 percent of the LTA). The 50-year flood zone covered

4 percent of the LTA and riparian vegetation covered less than 1 percent.

R-CAT analysis indicated that decreases in riparian vegetation had occurred

at perennial and intermittent stream segments. Mean percentage of floodplain

converted to anthropogenic cover was less than 1 percent at perennial and

intermittent segments. The distribution and connectivity index was fair

(70 percent), so we determined that this KEC was moderately altered from

the NRV.

30V—Cryic Uplands in Volcanics

	 This LTA had 430 miles of perennial streams, over 1,010 miles of

intermittent streams, and 326 unconfined valley bottom acres (<1 percent of

the LTA). The 50-year flood zone covered 4 percent of the LTA and riparian

vegetation covered 1 percent. Most (69 percent) of the LTA was in managed

areas. R-CAT analysis indicated that decreases in riparian vegetation had

occurred at perennial and intermittent stream segments. Mean percentage

of floodplain converted to anthropogenic cover was 1 percent at perennial

segments and less than 1 percent at intermittent segments. The distribution

and connectivity index was fairly high (80 percent), so we determined that

this KEC was within the NRV.

40G—Cryic Basinlands in Granite

	 This LTA had over 60 miles of perennial streams, over 40 miles of

intermittent streams, and 151 unconfined valley bottom acres (1 percent of

the LTA). The 50-year flood zone covered 4 percent of the LTA and riparian

vegetation covered 1 percent. Most (76 percent) of the LTA was in managed

areas. R-CAT analysis indicated that riparian vegetation had increased at

perennial and intermittent stream segments. Mean percentage of floodplain

converted to anthropogenic cover was less than 1 percent at perennial and

intermittent segments. The distribution and connectivity index was high

(100 percent), so we determined that this KEC was within the NRV.
U.S. Forest Service RMRS GTR-394. 2019. 92

40Q—Cryic Basinlands in Quartzite

	 This LTA was entirely in managed areas, with over 10 miles of perennial

streams, over 10 miles of intermittent streams, and 11 unconfined valley

bottom acres (<1 percent of the LTA). The 50-year flood zone covered

6 percent of the LTA and riparian vegetation covered 1 percent. R-CAT

analysis indicated that decreases in riparian vegetation had occurred at

perennial and intermittent stream segments. Mean percentage of floodplain

converted to anthropogenic cover was less than 1 percent at perennial and

intermittent segments. The distribution and connectivity index was fairly

high (80 percent), so we determined that this KEC was within the NRV.

40V—Cryic Basinlands in Volcanics

	 This LTA was entirely in managed areas, with over 10 miles of perennial

streams, over 5 miles of intermittent streams, and 32 unconfined valley

bottom acres (1 percent of the LTA). The 50-year flood zone covered

6 percent of the LTA and riparian vegetation covered 2 percent. R-CAT

analysis indicated that riparian vegetation had increased at perennial and

intermittent stream segments. Mean percentage of floodplain converted to

anthropogenic cover was less than 1 percent at perennial and intermittent

segments. The distribution and connectivity index was high (100 percent),

so we determined that this KEC was within the NRV.

50G—Glacial Troughlands in Granite

	 This LTA had over 440 miles of perennial streams, over 260 miles of

intermittent streams, and 2,521 unconfined valley bottom acres (1 percent

of the LTA). The 50-year flood zone covered 5 percent of the LTA and

riparian vegetation covered 1 percent. Most (55 percent) of the LTA was in

Wilderness. There was less than 1 acre of reservoirs, or 0.0005 acres per

perennial stream mile. R-CAT analysis indicated that decreases in riparian

vegetation had occurred at perennial and intermittent stream segments.

Mean percentage of floodplain converted to anthropogenic cover was less

than 1 percent at perennial and intermittent segments. The distribution and

connectivity index was high (100 percent), so we determined that this KEC

was within the NRV.

50M—Glacial Troughlands in Mixed Geology

	 This Wilderness LTA had 3 miles of perennial streams, less than

1 mile of intermittent streams, and no unconfined valley bottom acres

(0.1 percent of the LTA). The 50-year floodplain covered 3 percent of LTA

and riparian vegetation covered 2 percent. R-CAT analysis indicated that

riparian vegetation had increased perennial stream segments and decreased

at intermittent segments. Mean percentage of floodplain converted to

anthropogenic cover was 0 percent at perennial and intermittent segments.

The distribution and connectivity index was high (90 percent), so we

determined that this KEC was within its NRV.
U.S. Forest Service RMRS GTR-394. 2019. 93

50Q—Glacial Troughlands in Quartzite

	 This LTA had over 120 miles of perennial streams, over 110 miles of

intermittent streams, and 150 unconfined valley bottom acres (<1 percent

of the LTA). The 50-year flood zone covered 3 percent of LTA and riparian

vegetation covered less than 1 percent. Most (87 percent) of the LTA was

in managed areas. R-CAT analysis indicated that decreases in riparian

vegetation had occurred at perennial and intermittent stream segments.

Mean percentage of floodplain converted to anthropogenic cover was less

than 1 percent at perennial and intermittent segments. The distribution and

connectivity index was fairly high (80 percent), so we determined that this

KEC was within the NRV.

50S—Glacial Troughlands in Sedimentary Bedrock

	 This LTA had over 20 miles of perennial streams, over 80 miles of

intermittent streams, and 454 unconfined valley bottom acres (1 percent of

the LTA). The 50-year flood zone covered 5 percent of the LTA and riparian

vegetation covered less than 1 percent. Almost all of the LTA (99 percent)

was in managed areas. R-CAT analysis indicated that decreases in riparian

vegetation had occurred at perennial and intermittent stream segments.

Mean percentage of floodplain converted to anthropogenic cover was less

than 1 percent at perennial and intermittent segments. The distribution and

connectivity index was fair (70 percent), so we determined that this KEC was

moderately altered from the NRV.

50V—Glacial Troughlands in Volcanics

	 This LTA had over 170 miles of perennial streams, over 220 miles of

intermittent streams, and 301 unconfined valley bottom acres (<1 percent of

the LTA). The 50-year flood zone covered 5 percent of the LTA and riparian

vegetation covered 2 percent. Most (59 percent) of the LTA was in managed

areas. R-CAT analysis indicated that decreases in riparian vegetation had

occurred at perennial and intermittent stream segments. Mean percentage

of floodplain converted to anthropogenic cover was less than 1 percent at

perennial and intermittent segments. The distribution and connectivity index

was high (90 percent), so we determined that this KEC was within the NRV.

60G—Strongly Glaciated Lands in Granite

	 This LTA had nearly 300 miles of perennial streams, over 110 miles of

intermittent streams, and 475 unconfined valley bottom acres (<1 percent of

the LTA). The 50-year flood zone covered 3 percent of the LTA and riparian

vegetation covered less than 1 percent. Most (67 percent) of the LTA was

in Wilderness. R-CAT analysis indicated that minor decreases in riparian

vegetation had occurred at perennial and intermittent stream segments.

Mean percentage of floodplain converted to anthropogenic cover was less

than 1 percent at perennial and intermittent segments. The distribution and

connectivity index was high (100 percent), so we determined that this KEC

was within the NRV.
U.S. Forest Service RMRS GTR-394. 2019. 94

60M—Strongly Glaciated Lands in Mixed Geology

	 This LTA had 3 miles of perennial streams, 10 miles of intermittent

streams, and two unconfined valley bottom acres (<1 percent of the LTA).

The 50-year flood zone covered only 1 percent of the LTA and riparian

vegetation covered less than 1 percent. Most (74 percent) of the LTA was

in managed areas. R-CAT analysis indicated that decreases in riparian

vegetation had occurred at perennial and intermittent stream segments. Mean

percentage of floodplain converted to anthropogenic cover was 0 percent

at perennial and intermittent segments. The distribution and connectivity

index was fair (70 percent), so we determined that this KEC was moderately 

altered from the NRV.

60Q—Strongly Glaciated Lands in Quartzite

	 This LTA has over 260 miles of perennial streams, over 210 miles of

intermittent streams, and 5,606 unconfined valley bottom acres (3 percent of

the LTA). The 50-year flood zone covered 7 percent of the LTA and riparian

vegetation covered less than 1 percent. Most (96 percent) of the LTA was in

managed areas. There were 28 acres of reservoirs, or 0.1 acres per perennial

stream mile. R-CAT analysis indicated that decreases in riparian vegetation

had occurred at perennial and intermittent stream segments. Mean percentage

of floodplain converted to anthropogenic cover was less than 1 percent at

perennial and intermittent segments. The distribution and connectivity index

was fair (70 percent), so we determined that this KEC was moderately 

altered from the NRV.

60S—Strongly Glaciated Lands in Sedimentary Bedrock

	 This LTA was entirely in managed areas, with over 30 miles of perennial

streams, 150 miles of intermittent streams, and 129 unconfined valley bottom

acres (<1 percent of the LTA). The 50-year flood zone covered 3 percent of

the LTA and riparian vegetation covered less than 1 percent. R-CAT analysis

indicated that decreases in riparian vegetation had occurred at perennial and

intermittent stream segments. Mean percentage of floodplain converted to

anthropogenic cover was less than 1 percent at perennial and intermittent

segments. The distribution and connectivity index was fair (70 percent), so

we determined that this KEC was moderately altered from the NRV.

60V—Strongly Glaciated Lands in Volcanics

	 This LTA had over 130 miles of perennial streams, over 350 miles of

intermittent streams, and 158 unconfined valley bottom acres (<1 percent of

the LTA). The 50-year flood zone covered 3 percent of the LTA and riparian

vegetation covered less than 1 percent. Most (73 percent) of the LTA was in

managed areas. There were 37 acres of reservoirs, or 0.3 acres per perennial

stream mile. R-CAT analysis indicated that decreases in riparian vegetation

had occurred at perennial and intermittent stream segments. Mean percentage

of floodplain converted to anthropogenic cover was less than 1 percent at

perennial and intermittent segments. The distribution and connectivity index

was fair (60 percent), so we determined that this KEC was moderately 

altered from the NRV.
U.S. Forest Service RMRS GTR-394. 2019. 95

70Q—Dissected Foothill Lands in Quartzite

	 This LTA was entirely within a managed area, with 5 miles of perennial

streams, over 30 miles of intermittent streams, and 156 unconfined valley

bottom acres (2 percent of the LTA). The 50-year flood zone covered

5 percent of the LTA and riparian vegetation covered 1 percent. R-CAT

analysis indicated that decreases in riparian vegetation had occurred at

perennial and intermittent stream segments. Mean percentage of floodplain

converted to anthropogenic cover was greater than 10 percent at perennial

stream segments, most of which was conversion to developed land.

Anthropogenic conversion was greater than 1 percent at intermittent

segments. The distribution and connectivity index was low (50 percent)

because of conversion to developed land. For this reason, we determined

that this KEC was outside the NRV.

70S—Dissected Foothill Lands in Sedimentary Bedrock

	 This LTA had over 20 miles of perennial streams, over 110 miles of

intermittent streams, and 1,694 unconfined valley bottom acres (4 percent of

the LTA). The 50-year flood zone covered 7 percent of the LTA and riparian

vegetation covered less than 1 percent. Most (>99 percent) of the LTA was in

managed areas. There were 3 acres of reservoirs, or 0.1 acres per perennial

stream mile. R-CAT analysis indicated that decreases in riparian vegetation

had occurred at perennial and intermittent stream segments. Mean percentage

of floodplain converted to anthropogenic cover was less than 1 percent at

perennial and intermittent segments. The distribution and connectivity index

was fair (60 percent), so we determined that this KEC was moderately 

altered from the NRV.

70V—Dissected Foothill Lands in Volcanics

	 This LTA had over 70 miles of perennial streams, over 150 miles of

intermittent streams, and 390 unconfined valley bottom acres (1 percent of

the LTA). The 50-year flood zone covered 6 percent of the LTA and riparian

vegetation covered less than 1 percent. Most (99 percent) of the LTA was

in managed areas. There were 10 acres of reservoirs, or 0.1 per perennial

stream mile. R-CAT analysis indicated that decreases in riparian vegetation

had occurred at perennial and intermittent stream segments. Mean percentage

of floodplain converted to anthropogenic cover was less than 1 percent at

perennial and intermittent segments. The distribution and connectivity index

was fair (60 percent), so we determined that this KEC was moderately 

altered from the NRV.

VB—Valley Bottom

	 This most riparian of LTAs had over 870 miles of perennial streams, over

200 miles of intermittent streams, and 13,120 unconfined valley bottom acres

(13 percent of the LTA). The 50-year flood zone covered 24 percent of the

LTA and riparian vegetation covered 8 percent. Most (87 percent) of the LTA

was in Wilderness. There were 22 acres of reservoirs, or 0.0002 per perennial

stream mile. R-CAT analysis indicated that decreases in riparian vegetation

had occurred at perennial and intermittent stream segments. Mean percentage

of floodplain converted to anthropogenic cover was greater than 1 percent

at perennial and intermittent segments. The distribution and connectivity

index was fair (70 percent), so we determined that this KEC was moderately 

altered from the NRV.
U.S. Forest Service RMRS GTR-394. 2019. 96

Appendix B—Distribution of Groundwater-Dependent Ecosystems 

(GDEs)

Methods

Land Type Association 

Summaries

	 We assessed the current distribution of springs and groundwaterdependent ecosystems (GDE) wetlands for each land type associations (LTA)

on the Salmon-Challis National Forest (SCNF). If information on drivers,

stressors, or indicators was lacking, we noted that insufficient information

was available to make a determination. We identified stressors if the value

of the stressor for the LTA was greater than 50 percent of other LTAs on

the Forest. We used relative GDE density, as well as a comparison between

managed and reference areas as indicators of the current distribution of

spring and GDE wetlands. GDE distribution was considered within the

natural range of variation (NRV) if the GDE density of the managed portion

of the LTA was comparable to the range of reference conditions for that

geologic setting. GDE distribution was considered moderately altered

from the NRV if the GDE density of the managed portion was less than the

inner fence for outliers determined by the distribution of GDEs in reference

areas. GDE distribution was considered outside the NRV if the density of the

managed portion was less than the outer fence for outliers determined by the

distribution of GDEs in reference areas.

10G—Steep Canyonlands in Granite

	 Stressors to the distribution of springs in this LTA included diversions

and mining. The impacts of diversions were somewhat extensive throughout

the LTA, but large portions of the LTA did not have any diversions. Mines

were extensive throughout the LTA.

	 Spring Distribution: The spring density in 10G was 0.00005 springs/acre.

The number of springs was consistent with the climate and geology of this

LTA and the spring density within reference areas did not differ from the

spring density of managed areas, suggesting that spring distribution was

within the NRV.

	 GDE Wetland Distribution: According to the NWI dataset, there were 25

palustrine emergent wetlands (PEMB) wetlands with 6.8 total acres in this

LTA. Smith et al. (2017) documented 22 potential fens totaling 33 acres. Of

these, three were considered likely fens. There was insufficient information

on the distribution of wetland GDEs, particularly in the north zone of the

Forest, to determine the NRV status of GDE distribution in 10G.

10M—Steep Canyonlands in Mixed Geology

	 This is a very small LTA with no documented springs or GDE wetlands.

There was insufficient information on the geologic setting to determine the

NRV status of this LTA.
U.S. Forest Service RMRS GTR-394. 2019. 97

10Q—Steep Canyonlands in Quartzite

	 Stressors in this LTA included roads, diversions, and mines. Roads were

somewhat extensive throughout the LTA. The impacts of diversions were

fairly localized within 10Q. Mines extended throughout the LTA.

	 Spring Distribution: The spring density in 10Q was 0.00005 springs/acre.

Spring distribution in this LTA appeared to be primarily driven by geology

and the spring density of managed areas was slightly greater than reference

areas, indicating that spring distribution in this LTA was within the NRV.

	 GDE Wetland Distribution: According to the NWI database, there was

a single PEMB wetland that was 0.2 acres in this LTA. Smith et al. (2017)

documented one potential fen totaling 2 acres. There was insufficient 

information on the distribution of GDE wetlands, particularly in the north

zone of the Forest, to determine the NRV status of this LTA.

10S—Steep Canyonlands in Sedimentary Bedrock

	 The only stressor we identified in this LTA was mining. The extent of

mines throughout the LTA was localized.

	 Spring Distribution: This is a small LTA with no documented springs.

The lack of springs in this LTA appeared to be driven by geology. Spring

distribution was within the NRV in 10S.

	 GDE Wetland Distribution: According to the National Wetlands

Inventory (NWI) database, there were no documented PEMB wetlands in

this LTA. Smith et al. (2017) described a single potential fen that was less

than 1 acre in size. There was insufficient information on the distribution of

GDE wetlands, particularly in the north zone of the Forest, to determine the

NRV status of this LTA.

10V—Steep Canyonlands in Volcanics

	 Stressors in 10V included high severity fire and diversions. Reference

areas and managed areas had both experienced high severity fire, suggesting

this was a natural stressor. Impacts from diversions were localized in this

LTA, with large sections having no diversions.

	 Spring Distribution: There were 0.00009 springs/acre in 10V. Despite the

stressors, spring density within reference areas was similar to spring density

in managed areas. It appeared spring distribution was primarily driven by

geology. Spring distribution was considered within the NRV in this LTA.

	 GDE Wetland Distribution: According to the NWI database, there were

three PEMB wetlands that totaled 0.4 acres in this LTA. Smith et al. (2017)

documented two potential fens that totaled 1 acre in this LTA. There was

insufficient information on the distribution of GDE wetlands, particularly in

the north zone of the Forest, to determine the NRV status of this LTA.
U.S. Forest Service RMRS GTR-394. 2019. 98

20G—Mountain Slopelands in Granite

	 Stressors in this LTA included diversions and high severity burns. The

impact of diversions was limited due to localized distribution. High severity

fire had occurred in both managed and reference areas, suggesting it was a

natural stressor.

	 Spring Distribution: The spring density in this LTA was 0.00009 springs/

acre. The spring distribution appeared to be primarily driven by geology and

the spring density of reference areas did not differ from the spring density

of managed area, indicating that spring distribution was within the NRV in

20G.

	 GDE Wetland Distribution: According to the NWI database, there

were three PEMB wetlands totaling 2.6 acres in this LTA. Smith et al.

(2017) documented 15 potential fens totaling 14 acres in 20G. There was

insufficient information on the distribution of GDE wetlands, particularly in

the north zone of the Forest, to determine the NRV status of this LTA.

20M—Mountain Slopelands in Mixed Geology

	 This is a very small LTA with no documented springs or GDE wetlands.

This LTA had a relatively high mine density (90th percentile), but this was a

result of a single mine. There was insufficient information on the geologic

setting to determine the NRV status for spring or fen distribution in this LTA.

20Q—Mountain Slopelands in Quartzite

	 This LTA was among those most impacted by roads, with a road density

greater than 90 percent of other LTAs on the Forest. Additionally, roads

were located throughout the LTA and their impacts were extensive. About

10 percent of this LTA had burned at high severity, a greater percentage than

80 percent of LTAs on the Forest. High severity fire was fairly localized

and impacted the reference area more than the managed area. The diversion

density in this LTA was moderately high. Like roads, diversions extended

throughout the LTA and their impact was extensive.

	 Spring Distribution: The spring density in this LTA was 0.00010 springs/

acre. Geology appeared to be the primary driver of spring distribution and

there were more springs in managed areas than reference areas, suggesting

spring distribution was within the NRV in this LTA.

	 GDE Wetland Distribution: According to the NWI database, there were

two PEMB wetlands totaling 0.3 acres in this LTA. Smith et al. (2017)

documented 43 potential fens totaling 37 acres. Of these, one was a likely

fen. The SCNF completed an assessment of the Cove Creek GDE. This

GDE was not documented in the NWI database and suggested that GDE

wetlands were likely prevalent on the northern sections of the Forest. The

assessment only contained photos. There was insufficient information on

the distribution of GDE wetlands, particularly in the north zone of the Forest,

to determine the NRV status of this LTA.
U.S. Forest Service RMRS GTR-394. 2019. 99

20S—Mountain Slopelands in Sedimentary Bedrock

	 The stressors in this LTA included diversions, mining, and roads. The

impact from diversions was localized. Mines were scattered throughout the

LTA, extending their impacts. There were 0.0012 road miles/acre in this LTA,

which was greater than 60 percent of other LTAs on the Forest. Roads were

somewhat localized.

	 Spring Distribution: There were 0.00019 springs/acre in this LTA.

Despite stressors, there was no difference in the spring densities of managed

and reference areas. Climate and geology appeared to remain the primary

drivers of spring distribution and this LTA was within the NRV.

	 GDE Wetland Distribution: According to the NWI database, there

was a single PEMB wetland that totaled 0.4 acres in this LTA. Smith et al.

(2017) documented 14 potential fens totaling 44 acres in 20S. There was

insufficient information on the distribution of GDE wetlands, particularly in

the north zone of the Forest, to determine the NRV status of this LTA.

20V—Mountain Slopelands in Volcanics

	 The stressors in this LTA included roads and diversions. Roads were

somewhat localized throughout the managed portion and large parts of this

LTA were located in Wilderness and were not impacted by roads. Diversions

were fairly localized within the managed portion of this LTA.

	 Spring Distribution: The spring density in this LTA was 0.00016 springs/

acre. The primary driver of spring distribution appeared to be geology and

the spring density within reference conditions was comparable to managed

portions. This LTA was considered within the NRV.

	 GDE Wetland Distribution: According to the NWI database, there were

293 PEMB wetlands with a total acreage of 282 in this LTA. Smith et al.

(2017) documented 302 potential fens totaling 285 acres in this LTA. Of

these, eight were classified as likely fens. The SCNF had completed six

assessments of GDEs in this LTA: Dry Canyon, Burnt Hollow, Bear Creek,

Lower Grove, Swan Basin-Chandler Springs, and Deer Park Upper Adams.

None of these was documented in the NWI database and indicated that there

were likely numerous undocumented GDE wetlands on the north zone of the

Forest. Fen characteristics, including peat accumulation, were observed at the

Bear Creek and Burnt Hollow GDEs. There was insufficient information on

the distribution of GDE wetlands, particularly in the north zone of the Forest,

to determine the NRV status of this LTA.
U.S. Forest Service RMRS GTR-394. 2019. 100

30G—Cryic Uplands in Granite

	 Stressors in this LTA included high severity burns and mines. High

severity fires had occurred both in the managed and reference areas of

this LTA, suggesting it was a natural stressor. Mine locations were fairly

extensive throughout the LTA.

	 Spring Distribution: The spring density in this LTA was 0.00014 springs/

acre. The spring distribution appeared to be primarily driven by geology and

the spring density in managed areas was greater than the spring density of

reference areas, suggesting that spring distribution was within the NRV.

	 GDE Wetland Distribution: According to the NWI database, there were

417 PEMB wetlands totaling 269 acres in this LTA. Smith et al. (2017)

documented 258 potential fens with a total acreage of 314. Of these, 30 were

likely fens. There was insufficient information on the distribution of GDE

wetlands, particularly in the north zone of the Forest, to determine the NRV

status of this LTA.

30M—Cryic Uplands in Mixed Geology

	 This is an extremely small LTA with no documented springs or PEMB

wetlands. There was insufficient information to determine the NRV status

of spring or GDE wetland distribution of this LTA.

30Q—Cryic Uplands in Quartzite

	 Stressors in this LTA included roads and high severity fire. Roads were

extensive throughout the managed portion of 30Q. The impacts of high

severity fire were somewhat localized and impacted both the reference and

managed areas.

	 Spring Distribution: The spring density in this LTA was 0.00020

springs/acre. Despite the stressors, the spring density of managed areas was

comparable to reference conditions and the primary driver appeared to be

geology. The LTA was considered within the NRV.

	 GDE Wetland Distribution: According to the NWI database, there were

five PEMB wetlands totaling 0.9 acres in this LTA. Smith et al. (2017)

documented 115 potential fens with a total acreage of 103. Of these, 13 were

likely fens. There was insufficient information on the distribution of GDE

wetlands, particularly in the north zone of the Forest, to determine the NRV

status of this LTA.

30S—Cryic Uplands in Sedimentary

Levels of stressors in this LTA were low.

	 Spring Distribution: There were 0.00015 springs/acre in this LTA. The

primary driver of spring distribution in 30S appeared to be geology. Spring

distribution was within the NRV.
U.S. Forest Service RMRS GTR-394. 2019. 101

	 GDE Wetland Distribution: According to the NWI database, there

were 12 PEMB wetlands totaling 15 acres in this LTA. Smith et al. (2017)

documented 25 potential fens with a total acreage of 11. The SCNF

completed a single GDE assessment in 30S: Lake Creek. This GDE was

not documented in the NWI database and suggests that GDE wetlands were

underestimated on the northern zone of the Forest. There was insufficient 

information on the distribution of GDE wetlands, particularly in the north

zone of the Forest, to determine the NRV status of this LTA.

30V—Cryic Uplands in Volcanic

	 Stressors in this LTA included high severity fire and altered temperature

and precipitation regimes. High severity burns were somewhat localized

and occurred both within reference and managed areas. The average winter

temperature from 1985 to 2015 was 2.9 °F warmer than the average of the

last 100 years. In the same timeframe, winter precipitation had decreased by

9 percent.

	 Spring Distribution: This LTA had more springs than any other LTA on

the Forest: 0.00039 springs/acre (167 documented springs). The land type

provided important spring habitat and potentially was vulnerable to climate

change. Despite stressors, the primary driver of spring distribution in 30V

appeared to be geology and the spring density of managed areas was greater

than that of reference areas. Spring distribution was within the NRV in this

LTA.

	 GDE Wetland Distribution: According to the NWI database, there

were 426 PEMB wetlands totaling 207 acres in this LTA. All of these GDE

wetlands were located in managed areas. Smith et al. (2017) documented

164 potential fens with a total acreage of 112 in this LTA. Of these, nine

were considered likely fens. There was insufficient information on the

distribution of GDE wetlands, particularly in the north zone of the Forest, to

determine the NRV status of this LTA.

40G—Cryic Basinlands in Granite

	 Stressors in this LTA included high severity fire, roads, and mines. The

impacts of high severity fire were localized and occurred entirely in the

reference area. The impacts of roads were very localized. Mines were fairly

extensive throughout the LTA.

	 Spring Distribution: This is a very small LTA that only had two

documented springs. The spring density in this LTA was 0.00007 springs/

acre. This value was comparable to reference conditions and the primary

driver appeared to be geology. This LTA was considered within the NRV.

	 GDE Wetland Distribution: According to the NWI database, there were

no documented GDE wetlands in this LTA. Based on geology and climate,

we expected that this LTA likely did contain GDE wetland systems that had

not been documented by the Forest or NWI. Smith et al. (2017) described

86 potential fens with a total acreage of 367. Of these, five were considered

likely fens. There was insufficient information on the distribution of GDE

wetlands, particularly in the north zone of the Forest, to determine the NRV

status of this LTA.
U.S. Forest Service RMRS GTR-394. 2019. 102

40Q—Cryic Basinlands in Quartzite

	 Stressors in this LTA included high severity fire and altered temperature

and precipitation regimes. About 26 percent of this LTA had experienced

high severity burns, more than any other LTA on the Forest. The average

winter temperature between 1985 and 2015 was 3.1 °F warmer than that of

the previous century. During the same timeframe, winter precipitation had

decreased by about 4 percent.

	 Spring Distribution: This is a small LTA with no documented springs.

There was no reference area for this LTA, but based on the geology and

land type we expected there were undocumented springs in 40Q. There was

insufficient information to evaluate the NRV status of spring distribution.

	 GDE Wetland Distribution: According to the NWI database, there were

no documented PEMB wetlands in this LTA. Based on geology and climate,

we expected that this LTA likely did contain GDE wetland systems that had

not been documented by the Forest or NWI. Smith et al. (2017) reported

41 potential fens totaling 50 acres in 40Q. Of these, eight were considered

likely fens. There was insufficient information on the distribution of GDE

wetlands, particularly in the north zone of the Forest, to determine the NRV

status of spring distribution.

40V—Cryic Basinlands in Volcanics

	 Stressors in this LTA included roads and mines. Both road and mining

impacts were fairly localized.

	 Spring Distribution: This is a small LTA with no documented springs.

There was no reference area in this LTA for comparison, but based on the

geology and land type we expected there were undocumented springs in 40V.

There was insufficient information to evaluate the NRV status of spring

distribution.

	 GDE Wetland Distribution: According to the NWI database, there

were no documented PEMB wetlands in this LTA. Based on geology and

climate, we expected that this LTA likely did contain GDE wetland systems

that had not been documented by the Forest or NWI. Smith et al. (2017)

reported eight potential fens totaling 10 acres in this LTA. Of these, two

were considered likely fens. There was insufficient information on the

distribution of GDE wetlands, particularly in the north zone of the Forest, to

determine the NRV status of this LTA.

50G—Glacial Troughlands in Granite

	 Stressors in this LTA included high severity fire and altered temperature

and precipitation regimes. High severity fire occurred in reference and

managed areas, suggesting it was a natural stressor. Between 1985 and 2015,

winter temperatures were 3.0 °F warmer than the previous century and in the

same timeframe winter precipitation had decreased by 9 percent.

	 Spring Distribution: The spring density of this LTA was 0.00004

springs/acre. Spring distribution of managed areas was comparable to spring

distribution of reference areas and the primary driver of density in this LTA

appeared to be geology and land type. This LTA was considered within the NRV.
U.S. Forest Service RMRS GTR-394. 2019. 103

	 GDE Wetland Distribution: According to the NWI database, there were

424 PEMB wetlands totaling 348 acres in this LTA. Based on geology,

climate, and past glaciation, we expected that this LTA likely contained a

larger number of GDE wetland systems that had not been documented by

the Forest or NWI. Smith et al. (2017) recorded 332 potential fens totaling

568 acres. Of these, 33 were considered likely fens. There was insufficient 

information on the distribution of GDE wetlands, particularly in the north

zone of the Forest, to determine the NRV status of this LTA.

50M—Glacial Troughlands in Mixed Geology

	 This is a very small LTA with no documented springs or GDE wetlands.

There was insufficient information to determine the NRV status of spring or

GDE wetland distribution in this LTA.

50Q—Glacial Troughlands in Quartzite

	 Levels of stressors in this LTA were low.

	 Spring Distribution: The spring density in this LTA was 0.00004 springs/

acre. There were nine documented springs and all were located in managed

areas. It appeared climate and geology were the primary drivers of spring

density in this LTA and spring distribution was within the NRV in 50Q.

	 GDE Wetland Distribution: According to NWI there were no PEMB

wetlands in this LTA, but the SCNF had completed an assessment at the Lee

Creek Eightmile Large GDE. Based on geology and climate, we expected

that this LTA likely did contain additional GDE wetland systems that had

not been documented by the Forest or NWI. Smith et al. (2017) reported 48

potential fens totaling 39 acres in this LTA. Of these, five were considered

likely fens. There was insufficient information on the distribution of GDE

wetlands, particularly in the north zone of the Forest, to determine the NRV

status of this LTA.

50S—Glacial Troughlands in Sedimentary Bedrock

	 Stressors in this LTA included roads, mining, and altered temperature and

precipitation regimes. Roads extended throughout the LTA, but the location

of mines was somewhat localized. The average winter temperature from 1985

to 2015 was 3.0 °F warmer than the average of the previous century. In the

same timeframe, winter precipitation had decreased by 12 percent.

	 Spring Distribution: There were 0.00008 springs/acre in this LTA. All of

the springs were located in managed areas and geology appeared to be the

primary driver of spring distribution. This LTA was considered within the

NRV.

	 GDE Wetland Distribution: According to the NWI database, there was

a single PEMB wetland totaling 0.1 acre in this LTA. Based on geology and

climate, we expected that this LTA likely did contain additional GDE wetland

systems that had not been documented by the Forest or NWI. Smith et al.

(2017) reported 14 potential fens totaling 12 acres in this LTA. There was

insufficient information on the distribution of GDE wetlands, particularly in

the north zone of the Forest, to determine the NRV status of this LTA.
U.S. Forest Service RMRS GTR-394. 2019. 104

50V—Glacial Troughlands in Volcanics

	 The only stressor identified in this LTA was altered temperature and

precipitation regimes. The average winter temperature from 1985 to 2015

was 2.9 °F warmer than the previous century. During the same timeframe,

winter precipitation had decreased by about 9 percent.

	 Spring Distribution: The spring density in this LTA was 0.00012 springs/

acre. Climate and geology appeared to be the primary drivers of spring

distribution and the density of springs within managed areas was greater than

the spring density of reference areas in this LTA. Spring distribution was

within the NRV in this LTA.

	 GDE Wetland Distribution: According to the NWI database, there were

84 PEMB wetlands totaling 46 acres. Based on geology and climate, we

expected that this LTA likely did contain additional GDE wetland systems

that had not been documented by the Forest or NWI. Smith et al. (2017)

reported 78 potential fens totaling 78 acres in this LTA. Of these, six

were considered likely fens. There was insufficient information on the

distribution of GDE wetlands, particularly in the north zone of the Forest, to

determine the NRV status of this LTA.

60G—Strongly Glaciated Lands in Granite

	 Stressors in this LTA included high severity fire, mining, and altered

temperature and precipitation regimes. This LTA was among those with the

largest percentage burned at high severity (80th percentile). The number of

mines/acre was low, but they were highly concentrated within the managed

portion of the LTA. The average winter temperature from 1985 to 2015 was

2.9 °F warmer than the previous century. During the same timeframe, winter

precipitation decreased by 9 percent.

	 Spring Distribution: The spring density of this LTA was 0.00004 springs/

acre. Geology appeared to be the primary driver of spring distribution and the

spring density of managed areas was only slightly less than the spring density

of reference areas. This LTA was considered within the NRV.

	 GDE Wetland Distribution: According to the NWI database, there were

397 PEMB wetlands totaling 243 acres in this LTA. Based on geology and

climate, we expected that this LTA likely does contain additional GDE

wetland systems that had not been documented by the Forest or NWI. Smith

et al. (2017) documented 545 potential fens totaling 511 acres in this LTA.

Of these, 107 were considered likely fens. This LTA contained the greatest

number of fens mapped by the Colorado Natural Heritage Program (Smith

et al. 2017). There was insufficient information on the distribution of GDE

wetlands, particularly in the north zone of the Forest, to determine the NRV

status of this LTA.
U.S. Forest Service RMRS GTR-394. 2019. 105

60M—Strongly Glaciated Lands in Mixed Geology

	 The main stressor in this LTA was altered temperature and precipitation

regimes. The average winter temperature between 1985 and 2015 was 3.2 °F

warmer than the previous century. This was a larger increase in temperature

than any other LTA on the Forest. During the same timeframe, winter

precipitation had decreased by 19 percent. This is a larger deviation than any

other LTA on the Forest.

	 Spring Distribution: This is a fairly small LTA with a single documented

spring. All of this LTA was managed and there was no description of the

geologic setting. There was insufficient information to determine the NRV

status of spring distribution in this LTA.

	 GDE Wetland Distribution: According to the NWI database, there were

five PEMB wetlands totaling 0.9 acres in this LTA. Smith et al. (2017)

documented 13 potential fens with a total acreage of 8 in this LTA. Of these,

one was considered a likely fen. There was insufficient information on the

geology of this LTA and the distribution of GDE wetlands, particularly in the

north zone of the Forest, to determine the NRV status of this LTA.

60Q—Strongly Glaciated Lands in Quartzite

	 The primary stressor in this LTA was altered temperature and

precipitation regimes. The average winter temperature from 1985 to 2015

was 3.0 °F warmer than the previous century. During the same timeframe,

winter precipitation decreased by 6 percent.

	 Spring Distribution: The spring density in this LTA was 0.00018 springs/

acre. Natural climate and geology appeared to be the primary drivers of

spring distribution in 50V and the density of springs within managed areas

was greater than the spring density of reference areas. Spring distribution was

within the NRV in this LTA.

	 GDE Wetland Distribution: According to the NWI database, there were

12 PEMB wetlands totaling 35 acres in this LTA. Based on geology and

climate, we expected that this LTA likely contained additional GDE wetland

systems that had not been documented by the Forest or NWI. Smith et al.

(2017) recorded 434 potential fens totaling 631 acres in 60Q. Of these, 74

were considered likely fens. There was insufficient information on the

distribution of GDE wetlands, particularly in the north zone of the Forest, to

determine the NRV status of this LTA.

60S—Strongly Glaciated Lands in Sedimentary Bedrock

	 The primary stressor in this LTA was altered temperature and

precipitation regimes. The average winter temperature between 1985 and

2015 was 3.0 °F warmer than that of the previous century. During the same

timeframe winter precipitation had decreased by 15 percent.
U.S. Forest Service RMRS GTR-394. 2019. 106

	 Spring Distribution: The spring density in this LTA was 0.00018 springs/

acre. Climate and geology appeared to be the primary drivers of spring

distribution in 60S. The density of springs within managed areas was greater

than the spring density of reference areas. Spring distribution was within the

NRV in this LTA.

	 GDE Wetland Distribution: According to the NWI database, there were

four PEMB wetlands totaling 5 acres in this LTA. Based on geology and

climate, we expected that this LTA likely contained additional GDE wetland

systems that had not been documented by the Forest or NWI. Smith et al.

(2017) documented 87 potential fens totaling 78 acres in this LTA. Of these,

three were considered likely fens. There was insufficient information on the

distribution of GDE wetlands, particularly in the north zone of the Forest, to

determine the NRV status of this LTA.

60V—Strongly Glaciated Lands in Volcanics

	 The primary stressor in this LTA was altered temperature and

precipitation regimes. The average winter temperature between 1985 and

2015 was 3.0 °F warmer than that of the previous century. During the same

timeframe, winter precipitation had decreased by 13 percent.

	 Spring Distribution: The spring density in this LTA was 0.00017 springs/

acre. Climate and geology appeared to be the primary drivers of spring

distribution in 60V and the density of springs within managed areas was

greater than the spring density of reference areas. Spring distribution was

within the NRV in this LTA.

	 GDE Wetland Distribution: According to the NWI database, there were

284 PEMB wetlands totaling 205 acres in this LTA. Based on geology and

climate, we expected that this LTA likely contained additional GDE wetland

systems that had not been documented by the Forest or NWI. Smith et al.

(2017) documented 305 potential fens totaling 231 acres in this LTA. Of

these, 30 were considered likely fens. There was insufficient information on

the distribution of GDE wetlands, particularly in the north zone of the Forest,

to determine the NRV status of this LTA.

70Q—Dissected Foothill Lands in Quartzite

	 The stressors in this LTA included roads, diversions, and mines. Impacts

from roads and mines were somewhat localized, while diversions were very

limited in their extent.

	 Spring Distribution: This was a small LTA with two documented

springs, both of which were located in managed areas. The spring density

was 0.00020 springs/acre. Geology and climate appeared to be the primary

drivers of spring density in this LTA. Spring distribution was within the NRV

in 70Q.

	 GDE Wetland Distribution: According to the NWI database, there were

no documented PEMB wetlands in this LTA. Smith et al. (2017) documented

one potential fen totaling less than 1 acre in 70Q. There was insufficient 

information on the distribution of GDE wetlands, particularly in the north

zone of the Forest, to determine the NRV status of this LTA.
U.S. Forest Service RMRS GTR-394. 2019. 107

70S—Dissected Foothill Lands in Sedimentary Bedrock

	 Stressors in this LTA included roads and altered temperature and

precipitation regimes. Roads extend throughout the LTA. The average winter

temperature between 1985 and 2015 was 3.1 °F warmer than the previous

century. During the same timeframe, winter precipitation had decreased by

17 percent.

	 Spring Distribution: The spring density in this LTA was 0.00016 springs/

acre. Natural climate and geology appeared to be the primary drivers of

spring density. All of 70S was managed, providing no comparison to a

reference area. Spring distribution in this LTA was within the NRV.

	 GDE Wetland Distribution: According to the NWI database, there were

4 PEMB wetlands totaling 1.3 acres. Smith et al. (2017) documented nine

potential fens totaling 7 acres in this LTA. Of these, one was considered a

likely fen. There was insufficient information on the distribution of GDE

wetlands, particularly in the north zone of the Forest, to determine the NRV

status of this LTA.

70V—Dissected Foothill Lands in Volcanics

	 Stressors in this LTA included roads and altered temperature and

precipitation regimes. The impacts of roads were extensive throughout

the LTA. The average winter temperature between 1985 and 2015 was 3.0

°F warmer than the previous century. During the same timeframe, winter

precipitation had decreased by 11 percent.

	 Spring Distribution: The spring density in this LTA was 0.00049 springs/

acre, which was the largest spring density on the Forest. Natural climate and

geology appeared to be the primary drivers of spring distribution in this LTA.

All of the springs were located in managed areas. Spring distribution in this

LTA was within the NRV.

	 GDE Wetland Distribution: According to the NWI database, there were

24 PEMB wetlands totaling 18 acres in this LTA. The SCNF had documented

three GDEs in 70V: Dry Fork, Lee Creek Lee Creek, and Lee Creek-Walters

Unit, indicating that there were likely more GDE wetlands on the north

zone of the Forest. Smith et al. (2017) documented 34 potential fens totaling

17 acres in this LTA. Of these, one was considered a likely fen. There was

insufficient information on the distribution of GDE wetlands, particularly in

the north zone of the Forest, to determine the NRV status of this LTA.

VB—Valley Bottom

	 This LTA is composed of valley bottoms constructed by streams across

the Forest. It likely has variable geologic settings but consistently has water

tables at or near the surface throughout the majority. Stressors in this LTA

included roads, diversions, and mines. The impacts of roads, mines, and

diversions in this LTA were extensive.
U.S. Forest Service RMRS GTR-394. 2019. 108

	 Spring Distribution: The spring distribution in this LTA was 0.00025

springs/acre. There were 0.0005 more springs/acre in the reference areas

of this LTA compared to the managed areas. Due to the extensive and

cumulative impacts of roads, diversions, and mines, this LTA was outside the

NRV.

	 GDE Wetland Distribution: According to the NWI database, there were

327 PEMB wetlands totaling 418 acres in this LTA. Based on geology and

climate, we expected that this LTA likely did contain additional GDE wetland

systems that had not been documented by the Forest or NWI. Smith et al.

(2017) documented 293 potential fens totaling 1,206 acres in VB. Of these,

23 were considered likely fens. There was insufficient information on the

distribution of wetland GDEs, particularly in the north zone of the Forest, to

determine the NRV status of this LTA.

Smith, G.; Lemly, J.; Schroder, K. 2017. Fen mapping for the Salmon-Challis

National Forest. Fort Collins, CO: Colorado State University, Colorado

Natural Heritage Program. 31 p.

Reference
U.S. Forest Service RMRS GTR-394. 2019. 109

Appendix C—Surface Water and Groundwater Fluctuations

Methods

Indicator

Little or no alteration 

(5 points)

Moderate alteration 

(3 points)

Significant alteration 

(1 point)

Conifer encroachment of intermittent streams <25% 25% < x < 50% >50%

Upland encroachment of intermittent streams <25% 25% < x < 50% >50%

Conifer encroachment of perennial streams <25% 25% < x < 50% >50%

Upland encroachment of perennial streams <25% 25% < x < 50% >50%

Deviation in winter temperature <3 °F 3 °F < x < 3.2 °F >3.2 °F

Deviation in winter precipitation <5% 5% < x < 10% >10%

Table C1—Scoring of indicators of groundwater and surface water fluctuations within each LTA.

	 We scored six indicators for water fluctuations in surface water systems

based on whether they showed evidence of no, moderate, or substantial

alteration from reference conditions in the Frank Church-River of No Return

and Jim McClure-Jerry Peak Wildernesses. If the indicator had little or no

alteration it was given a score of 5; moderate alteration was given a score of

3; substantial alteration was given a score of 1 (table C1). The scores for each

land type associations (LTA) were summed and divided by the potential total

of 30 to give a percentage rating for each association. LTAs were considered

within the natural range of variation (NRV) for groundwater and surface

water fluctuations if the index was greater than 75 percent; moderately

altered from the NRV if the index was between 60 percent and 75 percent;

and outside the NRV if the index was less than 60 percent.

	 To evaluate water fluctuations at groundwater-dependent ecosystems

(GDEs), we used proper functioning condition (PFC) reports completed by

Salmon-Challis National Forest (SCNF) staff. These assessments included

information on whether the GDE experienced relatively frequent inundation,

whether water fluctuations were extreme, and if water supply was sufficient

to maintain hydric soils. We summarized these reports and used best

professional judgment to determine the status of water fluctuations at GDEs.
U.S. Forest Service RMRS GTR-394. 2019. 110

Land Type Association 

Summaries

10G—Steep Canyonlands in Granite

	 Surface water systems: This LTA is composed of steep canyonlands

that receive less than 15 to 20 inches of precipitation annually (SCNF

2004). Streams in 10G are usually ephemeral or intermittent with flashy

hydrographs that rapidly respond to precipitation events. This association

does not have a perennial water supply (SCNF 2004). The stressors in this

LTA that potentially were impacting water fluctuations were mining and trails

located within floodplains. The index score for groundwater and surface

water fluctuations in this LTA was 60 percent and 10G was considered to be

moderately altered from the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 10G.

10M—Steep Canyonlands in Mixed Geology

	 Surface water systems: The level of stressors in this LTA was relatively

low. The index score for groundwater and surface water fluctuations in this

LTA was 68 percent and 10M was considered to be moderately altered from

the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 10M.

10Q—Steep Canyonlands in Quartzite

	 Surface water systems: This LTA is composed of steep canyonlands

that receive less than 15 to 20 inches of precipitation annually (SCNF

2004). Streams in 10Q are usually ephemeral or intermittent with flashy

hydrographs that rapidly respond to precipitation events. This association

does provide a perennial water supply (SCNF 2004). The stressors in this

LTA that may be impacting groundwater and surface water fluctuations were

mining, roads, and recreation. The index score for groundwater and surface

water fluctuations in this LTA was 60 percent and 10Q was considered to be

moderately altered from the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 10Q.

10S—Steep Canyonlands in Sedimentary Bedrock

	 Surface water systems: This LTA is composed of steep canyonlands

that receive 10 to 20 inches of precipitation annually (SCNF 2004). Streams

in 10S are usually ephemeral or intermittent with flashy hydrographs that

rapidly respond to precipitation events. This association rarely provides

a perennial water supply (SCNF 2004). The stressors in this LTA were

recreation sites, roads located within floodplains, and grazing. The index

score for groundwater and surface water fluctuations in this LTA was 60

percent and 10S was considered to be moderately altered from the NRV.
U.S. Forest Service RMRS GTR-394. 2019. 111

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 10S.

10V—Steep Canyonlands in Volcanics

	 Surface water systems: This LTA is composed of steep canyonlands

that receive less than 15 to 20 inches of precipitation annually (SCNF

2004). Streams in 10V are usually ephemeral or intermittent with flashy

hydrographs that rapidly respond to precipitation events. This association

does not have a perennial water supply (SCNF 2004). The primary stressor

in this LTA was trails within the floodplain. The index score for groundwater

and surface water fluctuations in this LTA was 60 percent and 10V was

considered to be moderately altered from the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 10V.

20G—Mountain Slopelands in Granite

	 Surface water systems: The hydrology of this LTA is characterized

by wide climatic variation (SCNF 2004). Flow regimes of streams are

influenced by precipitation zone, elevation, and aspect. Water yield is greater

and more sustained from drainages with large proportions of north-facing

aspects and weak dissection. These areas can be a source of perennial

streamflow, but the majority of streams remain intermittent. The hydrologic

response ranges from slow to very rapid (SCNF 2004). The primary stressor

in this LTA that may have impacted water fluctuations was high severity fire.

The index score for groundwater and surface water fluctuations in this LTA

was 60 percent and 20G was considered to be moderately altered from the

NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 20G.

20M—Mountain Slopelands in Mixed Geology

	 Surface water systems: There is no description available of hydrology in

this LTA. The stressors in this LTA that may have impacted water fluctuations

were mining and trails located within floodplains. The index score for

groundwater and surface water fluctuations in this LTA was 68 percent and

20M was considered to be moderately altered from the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 20M.
U.S. Forest Service RMRS GTR-394. 2019. 112

20Q—Mountain Slopelands in Quartzite

	 Surface water systems: The hydrology of this LTA is characterized

by wide climatic variation (SCNF 2004). Flow regimes of streams are

influenced by precipitation zone, elevation, and aspect. Water yield is greater

and more sustained from drainages with large proportions of north-facing

aspects and weak dissection. These areas can be a source of perennial

streamflow, but the majority of streams remain intermittent. The hydrologic

response ranges from slow to very rapid (SCNF 2004). The stressors in this

LTA that may have impacted water fluctuations were vegetation mortality

throughout the LTA and within the floodplain and timber harvest. The index

score for groundwater and surface water fluctuations in this LTA was 68

percent and 20Q was considered to be moderately altered from the NRV.

	 GDEs: A single GDE assessment (Cove Creek-Cove Creek) had been

completed for a spring in this LTA. The report did not note any hydrologic

disturbances and indicated that there was no evidence that the aquifer

supplying groundwater was affected by withdrawal or loss of recharge. There

was insufficient information to evaluate the NRV status of groundwater and

surface water fluctuations at GDEs.

20S—Mountain Slopelands in Sedimentary Bedrock

	 Surface water systems: The hydrology of this LTA is characterized

by wide climatic variation (SCNF 2004). Flow regimes of streams are

influenced by precipitation zone, elevation, and aspect. Water yield is

greater and more sustained from drainages with large proportions of

north-facing aspects and weak dissection. These areas can be a source of

perennial streamflow, but the majority of streams remain intermittent. The

hydrologic response ranges from slow to very rapid. The LTA description

notes that beaver are present in this LTA, but no current data on distribution

or population size are available (SCNF 2004). The stressors in this LTA

that may have impacted water fluctuations were roads within floodplains

and livestock grazing. The index score for groundwater and surface water

fluctuations in this LTA was 52 percent and 20S was considered to be outside

the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 20S.
U.S. Forest Service RMRS GTR-394. 2019. 113

20V—Mountain Slopelands in Volcanics

	 Surface water systems: The hydrology of this LTA is characterized

by wide climatic variation (SCNF 2004). Flow regimes of streams are

influenced by precipitation zone, elevation, and aspect. Water yield is greater

and more sustained from drainages with large proportions of north-facing

aspects and weak dissection. These areas can be a source of perennial

streamflow, but the majority of streams remain intermittent. The hydrologic

response ranges from slow to very rapid (SCNF 2004). The primary stressor

in this LTA that may have impacted water fluctuations was livestock grazing.

The index score for groundwater and surface water fluctuations in this LTA

was 52 percent and 20V was considered to be outside the NRV.

	 GDEs: Eighteen GDE assessments had been completed for this

LTA. Fourteen reported the systems were functional-at-risk. Many of

the assessments indicated that drought reduced flows and limited spring

discharge. Channelization of spring channels and soil compaction had caused

surrounding areas to dry and the fluctuations of water in some GDEs had

been altered by diversions and stock ponds. Overall, groundwater and surface

water fluctuations in this LTA showed major impacts from drought and

livestock grazing. The KEC was considered outside the NRV for GDEs.

30G—Cryic Uplands in Granite

	 Surface water systems: This LTA is an important source of sustained

water yield and has high rates of percolation to groundwater systems (SCNF

2004). 30G receives large amounts of precipitation, the majority in the form

of snow. Snowpack remains on the landscape for long durations throughout

the LTA. The hydrologic response of streams is slow and overland flow is

rare. Formation of streams in this LTA is limited due to the high rates of

infiltration (SCNF 2004). The stressors in this LTA that may have impacted

water fluctuations were high severity fire and recreation sites within the

floodplains. The index score for groundwater and surface water fluctuations

in this LTA was 76 percent and 30G was considered to be within the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 30G.

30M—Cryic Uplands in Mixed Geology

	 Surface water systems: The level of stressors in this LTA was relatively

low. The index score for groundwater and surface water fluctuations in this

LTA was 68 percent and 30M was considered to be moderately altered from

the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 30M.
U.S. Forest Service RMRS GTR-394. 2019. 114

30Q—Cryic Uplands in Quartzite

	 Surface water systems: This LTA is an important source of sustained

water yield and has high rates of percolation to groundwater systems (SCNF

2004). 30Q receives large amounts of precipitation, the majority in the form

of snow. Snowpack remains on the landscape for long durations throughout

the LTA. The hydrologic response of streams is slow and overland flow is

rare. Formation of streams in this LTA is limited due to the high rates of

infiltration (SCNF 2004). The stressors in this LTA that may have impacted

water fluctuations included vegetation mortality throughout the LTA and

within the floodplain and livestock grazing. Because forage is limited in

this LTA, livestock tend to become concentrated in moist meadows and

valley bottoms (SCNF 2004). There is also pressure from elk, particularly

during the rut, and there may often be competition in wet areas between elk

and grazing (SCNF 2004). The index score for groundwater and surface

water fluctuations in this LTA was 68 percent and 30Q was considered to be

moderately altered from the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 30Q.

30S—Cryic Uplands in Sedimentary Bedrock

	 Surface water systems: This LTA is an important source of sustained

water yield and has high rates of percolation to groundwater systems (SCNF

2004). 30S receives moderate amounts of precipitation, the majority in

the form of snow. Snowpack remains on the landscape for long durations

throughout the LTA. The hydrologic response of streams is slow and

overland flow is rare. Formation of streams in this LTA is limited due to the

high rates of infiltration (SCNF 2004). The stressors in this LTA that may

have impacted water fluctuations were roads located within floodplains and

livestock grazing. Forage is limited to valley bottoms and moist headlands

and there is high use by livestock and elk in these riparian areas (SCNF

2004). The index score for groundwater and surface water fluctuations in this

LTA was 68 percent and 30S was considered to be moderately altered from

the NRV.

	 GDEs: A single GDE assessment had been completed by SCNF staff in

this LTA: Timber Creek-Trail Creek. The PFC noted that fen characteristics

were present at this site and that there were some impacts from grazing

by wild animals and a horse trail. There was no evidence that the aquifer

that supplied groundwater to the site was affected by withdrawal or loss of

recharge or that watershed conditions were negatively impacting the GDE.

The site was considered to be in properly functioning condition. Without

additional GDE assessments, there was insufficient information to evaluate

the NRV status of water fluctuations at GDEs in this LTA.
U.S. Forest Service RMRS GTR-394. 2019. 115

30V—Cryic Uplands in Volcanics

	 Surface water systems: This LTA is an important source of sustained

water yield and has high rates of percolation to groundwater systems (SCNF

2004). 30V receives large amounts of precipitation, the majority in the form

of snow. Snowpack remains on the landscape for long durations throughout

the LTA. The hydrologic response of streams is slow and overland flow is

rare. Formation of streams in this LTA is limited due to the high rates of

infiltration (SCNF 2004). The primary stressor in this LTA that may have

impacted water fluctuations was livestock grazing. Because forage tends

to be confined to isolated patches and valley bottoms in 30V, livestock use

within this LTA tends to be more concentrated within riparian areas (SCNF

2004). The index score for groundwater and surface water fluctuations in this

LTA was 68 percent and 30V was considered to be moderately altered from

the NRV.

	 GDEs: No GDE assessments have been completed in this LTA. There

was insufficient information to evaluate the status of water fluctuations at

GDEs in 30V.

40G—Cryic Basinlands in Granite

	 Surface water systems: This LTA receives a moderate to high amount

of precipitation, most of which falls in the form of snow (SCNF 2004).

Snowpack duration is average on south-facing slopes and long on northfacing, well protected aspects. The hydrologic response is rapid and overland

flow is common in areas with shallow soils and bedrock outcrops. There are

some wet meadows that slow the hydrologic response and store water that is

released throughout the year. 40G is a significant source of sustained water

yield. The LTA description notes that beaver are often found in streams with

low gradients and willow dominated riparian areas in this LTA, but there

are no data available on their current distribution or population size (SCNF

2004). The stressors in this LTA that may have impacted water fluctuations

were vegetation mortality throughout the LTA and within the floodplain and

livestock grazing. Valley bottoms often provide the principal forage supply

for cattle, elk, and deer (SCNF 2004). The index score for groundwater

and surface water fluctuations in this LTA was 76 percent and 40G was

considered to be within its NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 40G.
U.S. Forest Service RMRS GTR-394. 2019. 116

40Q—Cryic Basinlands in Quartzite

	 Surface water systems: This LTA receives moderate to high amounts

of precipitation and about half falls as snow (SCNF 2004). The duration of

snowpack is average on south-facing slopes and ridges and is long on northfacing aspects. The hydrologic response is slow on slopes and very slow in

wet meadows where the water table is at or near the surface. Valley bottoms

are the primary source of forage for cattle, elk, and deer. The LTA description

notes that beaver are often found in low gradient, willow lined streams,

but there are no data available on their current distribution or population

size (SCNF 2004). The stressors in this LTA that may have impacted

water fluctuations were high severity fire, trails within the floodplain, and

vegetation mortality in the LTA and the floodplains. The index score for

groundwater and surface water fluctuations in this LTA was 60 percent and

40Q was considered to be moderately altered from the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 40Q.

40V—Cryic Basinlands in Volcanics

	 Surface water systems: This LTA receives moderate to high amounts

of precipitation and about half falls as snow (SCNF 2004). The duration

of snowpack is average on south-facing slopes and ridges and is long on

north-facing aspects. The hydrologic response is slow on slopes and very

slow in wet meadows where the water table is at or near the surface. Valley

bottoms provide the principal source of forage for cattle, elk, and deer. The

LTA description notes that beaver are often found in low gradient, willow

lined streams, but there are no data available on their current distribution

or population size (SCNF 2004). The stressors in this LTA that may have

impacted water fluctuations were mining, timber harvest, grazing, and

vegetation mortality throughout the LTA and the floodplain. The index score

for groundwater and surface water fluctuations in this LTA was 76 percent

and 40V was considered to be within the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 40V.

50G—Glacial Troughlands in Granite

	 Surface water systems: This LTA receives a large amount of precipitation

and the majority falls as snow (SCNF 2004). Snowpack in 50G tends to

persist until early summer and this LTA produces a significant amount of

water throughout the year. The hydrologic response ranges from very slow

to average in the valley bottoms to rapid on the steep, glaciated sideslopes

(SCNF 2004). The level of stressors in this LTA were relatively low. The

index score for groundwater and surface water fluctuations in this LTA was

60 percent and 50G was considered to be moderately altered from the NRV.
U.S. Forest Service RMRS GTR-394. 2019. 117

	 GDEs: Three GDE assessments have been completed by Forest staff in

this LTA. All three reports indicated that the systems experienced relatively

frequent inundation and that fluctuations were excessive. Two assessments

recorded that drought was limiting flows and that riparian vegetation was

being impacted by reduced spring discharge. This is a large LTA and there

was insufficient information to evaluate the NRV status of GDE water

fluctuations.

50M—Glacial Troughlands in Mixed Geology

	 Surface water systems: The level of stressors in this LTA was relatively

low. The index score for groundwater and surface water fluctuations in this

LTA was 76 percent and 50M was considered to be within the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 50M.

50Q—Glacial Troughlands in Quartzite

	 Surface water systems: This LTA receives a large amount of precipitation

and the majority falls as snow (SCNF 2004). Snowpack in 50Q tends to

persist until early summer and this LTA produces a significant amount of

water throughout the year. The hydrologic response ranges from very slow

to average in the valley bottoms to rapid on the steep, glaciated sideslopes

(SCNF 2004). The stressors in this LTA that may have impacted water

fluctuations were vegetation mortality throughout the LTA and within the

floodplain. The index score for groundwater and surface water fluctuations in

this LTA was 68 percent and 50Q was considered to be moderately altered

from the NRV.

	 GDEs: Two GDE assessments had been completed in this LTA by SCNF

staff: Lee Creek-Big Eightmile and Deer Park-North Fork. One GDE was

a spring and the other displayed fen characteristics. Both PFC assessments

report nonfunctional troughs and impacts from livestock grazing at the sites.

Nevertheless, the assessments recorded that there was no evidence that the

aquifer supplying water was affected by withdrawal or loss of recharge. It

appeared that vegetation at the sites was transitioning to drier cover and

both GDEs were classified as functional-at-risk. There was insufficient 

information to evaluate the NRV status of water fluctuations at GDEs in this

LTA.

50S—Glacial Troughlands in Sedimentary Rocks

	 Surface water systems: This LTA receives a large amount of precipitation

and the majority falls as snow (SCNF 2004). Snowpack in 50S tends to

persist until early summer and this LTA produces a significant amount of

water throughout the year. The hydrologic response ranges from very slow

to average in the valley bottoms to rapid on the steep, glaciated sideslopes.

Valley bottoms are the primary forage source for both cattle and elk

(SCNF 2004). The primary stressor in this LTA that may have impacted

water fluctuations was livestock grazing. The index score for groundwater

and surface water fluctuations in this LTA was 60 percent and 50S was

considered to be moderately altered from the NRV.
U.S. Forest Service RMRS GTR-394. 2019. 118

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 50S.

50V—Glacial Troughlands in Volcanics

	 Surface water systems: This LTA receives a moderate amount of

precipitation and the majority falls as snow (SCNF 2004). Snowpack in

50V tends to persist until late spring at middle elevations and until early

summer at higher elevations. This LTA produces a significant amount of

water throughout the year. The hydrologic response ranges from very slow

to average in the valley bottoms to rapid on the steep, glaciated sideslopes

(SCNF 2004). The level of stressors in this LTA was relatively low. The

index score for groundwater and surface water fluctuations in this LTA was

76 percent and 50V was considered to be within its NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 50V.

60G—Strongly Glaciated Lands in Granite

	 Surface water systems: This LTA is high elevation and receives a large

amount of precipitation, the majority of which falls as snow (SCNF 2004).

Snowpack can persist until late summer in some locations. This association

is among the highest water producing LTAs. Cirque basins in 60G have a

very slow hydrologic response and these areas release water throughout drier

seasons (SCNF 2004). The level of stressors in this LTA was relatively low.

The index score for groundwater and surface water fluctuations in this LTA

was 92 percent, which is the highest index score of any LTA on the Forest.

60G was considered to be within its NRV.

GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 60G.

60M—Strongly Glaciated Lands in Mixed Geology

	 Surface water systems: The stressor in this LTA that may have impacted

water fluctuations is livestock grazing. Winter temperature increases and the

amount of reduced winter precipitation were greater than any other LTA on

the Forest. The index score for groundwater and surface water fluctuations in

this LTA was 44 percent and 60M was considered to be outside the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 60M.
U.S. Forest Service RMRS GTR-394. 2019. 119

60Q—Strongly Glaciated Lands in Quartzite

	 Surface water systems: This LTA is high elevation and receives a large

amount of precipitation, the majority of which falls as snow (SCNF 2004).

Snowpack can persist until late summer in some locations. This association

is among the highest water producing LTAs. Cirque basins in 60Q have a

very slow hydrologic response, high storage capacity, and these areas release

water throughout drier seasons (SCNF 2004). The stressors in this LTA that

may have impacted water fluctuations is vegetation mortality throughout

the LTA and livestock grazing. The index score for groundwater and surface

water fluctuations in this LTA was 60 percent and 60Q was considered to be

moderately altered from the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 60Q.

60S—Strongly Glaciated Lands in Sedimentary Bedrock

	 Surface water systems: This LTA is high elevation and receives a large

amount of precipitation, the majority of which falls as snow (SCNF 2004).

Snowpack can persist until late summer in some locations. This association

is among the highest water producing LTAs. Cirque basins in 60S have a

very slow hydrologic response, high storage capacity, and these areas release

water throughout drier seasons (SCNF 2004). The primary stressor in this

LTA that may have impacted water fluctuations was livestock grazing. Impact

from grazing is likely limited because steep slopes and difficult access makes

this association more suitable to big game species (SCNF 2004). The index

score for groundwater and surface water fluctuations in this LTA was 52

percent and 60S was considered to be outside the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 60S.

60V—Strongly Glaciated Lands in Volcanics

	 Surface water systems: This LTA is high elevation and receives a large

amount of precipitation, the majority of which falls as snow (SCNF 2004).

Snowpack can persist until late summer in some locations. This association

is among the highest water producing LTAs. Cirque basins in 60V have a

very slow hydrologic response, high storage capacity, and these areas release

water throughout drier seasons (SCNF 2004). The primary stressor in this

LTA that may have impacted water fluctuations was livestock grazing. The

index score for groundwater and surface water fluctuations in this LTA was

68 percent and 60V was considered to be moderately altered from the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of water fluctuations at GDEs

in 60V.
U.S. Forest Service RMRS GTR-394. 2019. 120

70Q—Dissected Foothill Lands in Quartzite

	 Surface water systems: This LTA is composed of foothills that receive

little precipitation (SCNF 2004). Snowpack duration tends to be short,

however it may persist longer on protected north-facing slopes. Streams

emerging from this LTA are generally ephemeral or intermittent with

somewhat flashy hydrographs. 70Q is not a perennial source of water (SCNF

2004). The stressors in this LTA that may have impacted water fluctuations

were mining, diversions, and grazing. Pressure within riparian areas may be

limited as 70Q is capable of supporting considerable amounts of grazing by

game and domestic livestock (SCNF 2004). The index score for groundwater

and surface water fluctuations in this LTA was 68 percent and 70Q was

considered to be moderately altered from the NRV.

	 GDEs: No GDE assessments have been completed in this LTA. There

was insufficient information to evaluate the status of water fluctuations at

GDEs in 70Q.

70S—Dissected Foothill Lands in Sedimentary Bedrock

	 Surface water systems: This LTA is composed of foothills that receive

little precipitation (SCNF 2004). Snowpack duration tends to be short, but

it may persist longer on protected north-facing slopes. Streams emerging

from this LTA are generally ephemeral or intermittent with somewhat flashy

hydrographs. 70Q is not a perennial source of water (SCNF 2004). The

stressors in this LTA that may have impacted water fluctuations were roads

within the floodplain and livestock grazing. Despite the high percentage

of the LTA with active grazing, pressure to riparian areas may be limited

due to gentle slopes and moderate to high production of forage throughout

the LTA (SCNF 2004). The index score for groundwater and surface water

fluctuations in this LTA was 60 percent and 70S was considered to be

moderately altered from the NRV.

	 GDEs: Two GDE assessments had been completed by SCNF staff in

this LTA: Spring Hill Site 3 and Sawmill Canyon/Head of Left Fork. Both

reports noted impacts from livestock and wild ungulate grazing and one

recorded that a tank was diverting flow from the spring. One PFC assessment

stated that there was no evidence that the aquifer supplying groundwater

was affected by withdrawal or loss of recharge. The second report indicated

that the system was inundated regularly frequently and that fluctuations

in water levels was not excessive. However, the assessment also indicates

that the seep complex is losing flow due to drought. There was insufficient 

information to evaluate the NRV status of water fluctuations at GDEs in this

LTA.
U.S. Forest Service RMRS GTR-394. 2019. 121

70V—Dissected Foothill Lands in Volcanics

	 Surface water systems: This LTA is composed of foothills that receive

little precipitation (SCNF 2004). Snowpack duration tends to be short but

it may persist longer on protected north-facing slopes. Streams emerging

from this LTA are generally ephemeral or intermittent with somewhat

flashy hydrographs. 70Q is not a perennial source of water (SCNF 2004).

The stressors in this LTA that may have impacted water fluctuations were

recreation sites and roads within the floodplain and livestock grazing. Slopes

tend to be too steep to supply forage for cattle and the primary use would be

domestic sheep (SCNF 2004). The index score for groundwater and surface

water fluctuations in this LTA was 52 percent and 70V was considered to be

outside the NRV.

	 GDEs: Twenty-seven GDE assessments had been completed by SCNF

staff in this LTA. Of these, 13 noted that the system experiences relatively

frequent inundation and 15 indicated that water fluctuations are not

excessive. Ten assessments recorded that the saturation of soils is sufficient

to compose and maintain hydric soils. The majority of the reports indicated

that drought was having some affect by either a total loss of flow, reduced

flow, or transition from perennial to ephemeral flow. Three of the reports

indicated that water fluctuations at the GDE may have been altered by the

Borah Peak Earthquake in 1983. In addition to natural disturbances, the

assessments also reported impacts from livestock and roads. GDEs in 70V

appeared especially sensitive to drought conditions. Due to the cumulative

stressors, impacts of altered temperature and precipitation in this LTA, and

anthropogenic effects recorded at one-third of the sampled sites, water

fluctuations at GDEs was considered outside the NRV in 70V.

VB—Valley Bottom

	 Surface water systems: The stressors in this LTA that may have impacted

water fluctuations were mining, diversions, recreation sites within the

floodplain, trails throughout the LTA and within the floodplain, and roads

throughout the LTA. The index score for groundwater and surface water

fluctuations in this LTA was 60 percent and VB was considered to be

moderately altered from the NRV.

	 GDEs: A single GDE assessment has been completed by SCNF staff in

this LTA. It recorded minor impacts from wild animal grazing. The report

indicated that there was no evidence that the aquifer supplying groundwater

was affected by groundwater withdrawal or loss of recharge and that flow

regulation was not affecting the site. Without additional assessments, there

was insufficient information to evaluate the NRV status of GDE water

fluctuations in this LTA.

Salmon-Challis National Forest [SCNF]. 2004. Landtype association and

landtypes of the Salmon-Challis National Forest. Unpublished report on

file with: U.S. Department of Agriculture, Forest Service, Salmon-Challis

National Forest, Salmon, ID.

Reference
U.S. Forest Service RMRS GTR-394. 2019. 122

Appendix D—Water Quality

Indicator Comparable to reference conditions Moderately altered Substantially altered

CTQd <58 ≥58 >76

Temperature <11.9 ≥11.9 >15.4

D50 >0.04 0.01 ≤ x ≤ 0.04 ≤0.01

Impaired streams <1% 1% ≤ x ≤ 10% >10%

Impaired waterbodies <1% 1% ≤ x ≤ 10% >10%

Table D1—Scoring of indicators of water quality within each LTA.

Methods 	 We scored five indicators for water quality of surface water systems

based on whether they showed evidence of no, moderate, or substantial

alteration from the natural range of variation (NRV). We determined a range

of reference conditions for macroinvertebrate communities, temperature,

and median substrate size by evaluating Pacfish-Infish Biological Opinion

(PIBO) sites within the Frank Church-River of No Return and Jim McClureJerry Peak Wilderness areas. We categorized these distributions by their

median, 1st quartile, 3rd quartile, and upper and lower outlier fences.

We then compared the median value of each indicator in each land type

associations (LTA) to the reference condition range and assigned a score

based on whether it was comparable to reference conditions, moderately

altered, or substantially altered (table D1). We used guidance from the

Watershed Condition Framework to determine thresholds for moderate and

significant alteration for the percentage of streams and waterbodies classified

as impaired. We only evaluated the NRV status if data were available for at

least four indicators. When no data existed for more than one indicator, we

determined there to be insufficient information to evaluate the NRV status. 

	 Indicators determined to be comparable to reference conditions were

given a score of 5, while moderately altered indicators were scored as a 3,

and significantly altered indicators were given a score of 1. The scores for

each LTA were summed and divided by the potential total to determine a

final water quality score. Finally, LTAs were considered within the NRV if

the water quality score was greater than 75 percent. They were identified as

moderately altered from the NRV if the water quality score was between 60

percent and 75 percent. LTAs were classified as outside the NRV if the water

quality score was less than 60 percent.
U.S. Forest Service RMRS GTR-394. 2019. 123

	 To evaluate groundwater-dependent ecosystems (GDE) water quality,

we used proper functioning condition (PFC) reports completed by SCNF

staff. These assessments included information on whether water quality

was sufficient to support riparian or wetland plants and if accumulation

of chemicals affecting productivity or composition was apparent. We

summarized these reports and used best professional judgment to determine

the NRV status of water quality at GDEs.

10G—Steep Canyonlands in Granite

	 Surface water systems: Stressors in this LTA included mining and

recreation. The percentage of impaired waterbodies, the macroinvertebrate

community, and fine sediment values were all comparable to reference

conditions. The average temperature and the percentage of impaired streams

were moderately altered from reference conditions. The overall water quality

score was 84 percent and the LTA was considered within the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 10G.

10M—Steep Canyonlands in Mixed Geology

	 Surface water systems: The level of stressors in this LTA was relatively

low. There was no macroinvertebrate, temperature, or fine sediment data

available. The percent of impaired streams and the percent of impaired

waterbodies were comparable to reference sites. However, without additional

indicators there was insufficient information to evaluate the status of water

quality in this LTA.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 10M.

10Q—Steep Canyonlands in Quartzite

	 Surface water systems: The stressors in this LTA included mining, roads,

and recreation. Despite these stressors, average temperature, fine sediment,

and percent of impaired waterbodies were comparable to reference sites.

The macroinvertebrate community and the percent of impaired streams were

moderately altered from reference conditions. The water quality score was 84

percent and the LTA was considered within the NRV for water quality.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 10M.

10S—Steep Canyonlands in Sedimentary Bedrock

	 Surface water systems: The stressors in this LTA included grazing

and roads. Despite these stressors the average temperature and percent

of impaired waterbodies were comparable to reference conditions. The

macroinvertebrate communities and fine sediments were moderately altered

from reference conditions and the percent of impaired streams was much

greater than reference conditions. The water quality score was 68 percent and

the LTA was moderately altered from the NRV.

	 GDE: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 10S.

Land Type Association 

Summaries
U.S. Forest Service RMRS GTR-394. 2019. 124

10V—Steep Canyonlands in Volcanics

	 Surface water systems: Stressors in this LTA included recreation,

specifically trails located within floodplains. The macroinvertebrate

community, average temperature, fine sediment, and percentage of impaired

waterbodies were all comparable to reference sites. The percentage of

impaired streams was moderately altered from reference sites. The water

quality score was 92 percent and the LTA was considered within its NRV.

	 GDE: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 10V.

20G—Mountain Slopelands in Granite

	 Surface water systems: The level of all stressors in this LTA was

relatively low. The macroinvertebrate community, average temperature, fine

sediment, percentage of impaired streams, and the percentage of impaired

waterbodies were all comparable to reference. The overall water quality score

was 100 percent and the LTA was considered within the NRV.

	 GDE: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 20G.

20M—Mountain Slopelands in Mixed Geology 

	 Surface water systems: The stressors in this LTA included mining and

recreation, specifically trails located within the floodplain. There were no

macroinvertebrate community, temperature, or fine sediment data available.

The percent of impaired streams and the percent of impaired waterbodies

were both comparable to reference sites. However, without additional

indicators there was insufficient information to evaluate the status of water

quality in this LTA.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 20M.

20Q—Mountain Slopelands in Quartzite

	 Surface water systems: The levels of all stressors in this LTA were

relatively low. The macroinvertebrate community, average temperature, and

fine sediment were all comparable to reference conditions. The percentage

of impaired streams was slightly greater than reference conditions and the

percent of impaired waterbodies was much greater than reference conditions.

The overall water quality score was 76 percent and the LTA was considered

within the NRV.

	 GDEs: A single GDE assessment (Cove Creek-Cove Creek) was

completed at a spring in this LTA in 2015. The report noted impacts to soils

from wild ungulate and livestock grazing and that herbivory was adversely

affecting the site. However, changes in water quality were not affecting the

GDE. The site was described as functioning at risk with a downward trend.

This LTA is large with only one GDE assessment available. Therefore, there

was insufficient information to evaluate GDE water quality in 20Q.
U.S. Forest Service RMRS GTR-394. 2019. 125

20S—Mountain Slopelands in Sedimentary Bedrock

	 Surface water systems: The stressors in this LTA included grazing and

roads. The macroinvertebrate community, average temperature, and fine

sediment were moderately altered from reference conditions. The percentage

of impaired streams and the percentage of impaired waterbodies were much

greater than reference conditions. Overall, the water quality score was 44

percent and the LTA was considered outside the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 20S.

20V—Mountain Slopelands in Volcanics

	 Surface water systems: The primary stressor in this LTA was

grazing. Average temperature was comparable to reference sites. The

macroinvertebrate community, fine sediment, and percent of impaired

streams were moderately altered from reference conditions. The percent of

impaired waterbodies was much greater than that of reference conditions.

Overall, the water quality score was 60 percent and the LTA was considered

moderately altered from the NRV.

	 GDEs: Forest staff completed 17 GDE Assessments within this LTA:

Smiley Meadow Spring, Antelope/Iron Bog/Big Canyon, Burnt Hollow,

Mahogany Gulch, Mahogany Gulch Bear Creek Pond 3, Middle Fork Swan

Basin, Antelope/Iron Bog/Spring, Dry Canyon GDE #1, Death Canyon Pond

5, Death Canyon Pond 6, Antelope/Bear Creek Unit, Antelope/Bear Creek

Unit Pond/Spring #7, Antelope/Bear Creek Unit Pond #5, Antelope/Bear

Creek Unit Pond #3, Swan Basin-Ted Whitaker, and Swan Basin-Chandler

Springs. Of these, Burnt Hollow, Mahogany Gulch Bear Creek Pond 3,

Middle Fork Swan Basin, Swan Basin-Ted Whitaker, Swan Basin Lower

Grove, and Swan Basin-Chandler Springs displayed fen characteristics.

Every PFC assessment in this LTA noted impacts to the GDE from grazing

and photos of the sites show erosion, hummocking, and soil disturbance from

livestock. However, all reports indicated that changes in water quality were

not impacting the system and GDE water quality was considered within the

NRV in 20V.

30G—Cryic Uplands in Granite

	 Surface water systems: The level of all stressors in this LTA was

relatively low. There was no macroinvertebrate community or temperature

data available. The percentage of impaired streams was comparable to

reference conditions, although the percentage of impaired waterbodies

was moderately greater than reference conditions. Fine sediment was

substantially altered from reference conditions. The water quality score was

60 percent and the LTA was considered moderately altered from the NRV,

but this determination was made with low confidence due to the lack of

macroinvertebrate and temperature indicators.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 30G.
U.S. Forest Service RMRS GTR-394. 2019. 126

30M—Cryic Uplands in Mixed 

	 Surface Water Quality: The level of all stressors in this LTA was

relatively low. There were no macroinvertebrate, temperature, or fine

sediment data available for 30M. The percent of impaired streams and the

percent of impaired waterbodies were both comparable to reference sites.

However, without additional indicators there was insufficient information to

evaluate the status of water quality in this LTA.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 30M.

30Q—Cryic Uplands in Quartzite

	 Surface water systems: The primary stressor in this LTA was grazing.

The macroinvertebrate community and average temperature were comparable

to reference conditions. Fine sediment and the percent of impaired streams

were moderately altered from reference conditions and the percent of

impaired waterbodies was much greater than reference conditions. The

water quality score was 68 percent and the LTA was considered moderately 

altered from the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 30Q.

30S—Cryic Uplands in Sedimentary Bedrock

	 Surface water systems: The stressors in this LTA included grazing and

roads. There were no macroinvertebrate community, temperature, or fine

sediment data available for 30S. The percent of impaired streams and the

percent of impaired waterbodies were both much greater than reference

conditions. However, without additional indicators there was insufficient 

information to evaluate the status of water quality in this LTA.

	 GDEs: A single GDE assessment had been completed in 2015 in

this LTA: Lake Creek Trail Creek Big Timber. This site did display fen

characteristics. The PFC report indicated that changes in water quality

were not affecting the system, but without additional assessments there was

insufficient information to evaluate GDE water quality in 30S.	

30V—Cryic Uplands in Volcanics

	 Surface water systems: The primary stressor in this LTA was grazing;

with limited forage, impacts are typically confined to valley bottoms where

moisture is available (SCNF 2004). The average stream temperature was

comparable to reference conditions. The macroinvertebrate community, fine

sediment, and percent of impaired streams were moderately altered from

reference conditions. The percentage of impaired waterbodies was much

greater than reference conditions. Overall, the water quality score was 60

percent and the LTA was considered moderately altered from the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 30V.
U.S. Forest Service RMRS GTR-394. 2019. 127

40G—Cryic Basinlands in Granite

	 Surface water systems: The primary stressor in this LTA was grazing.

The percentage of impaired waterbodies, the percentage of impaired streams,

and fine sediment values in this LTA were comparable to reference. The

macroinvertebrate community and average temperature were moderately

altered from reference conditions. Overall the water quality score was 84

percent and the LTA was considered within the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 40G.

40Q—Cryic Basinlands in Quartzite

	 Surface water systems: The stressors in this LTA included grazing and

recreation, specifically trails located within the floodplain. There were no

macroinvertebrate community, temperature, or fine sediment data for this

LTA. The percentage of impaired waterbodies was slightly greater than

reference conditions and the percent of impaired streams was much greater

than reference conditions. However, without additional indicators there was

insufficient information to evaluate the status of water quality in this LTA.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 40Q.

40V—Cryic Basinlands in Volcanics

	 Surface water systems: The stressors in this LTA included mining and

grazing. There were no macroinvertebrate community, temperature, or fine

sediment data for this LTA. There were no impaired waterbodies or streams

in 40V. However, without additional indicators there was insufficient 

information to evaluate the status of water quality in this LTA.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 40V.

50G-Glacial Troughlands in Granite

	 Surface water systems: The level of stressors in this LTA was low. The

macroinvertebrate community, average stream temperature, fine sediment,

and percentage of impaired streams were comparable to reference conditions.

The percentage of impaired waterbodies was slightly greater than reference

conditions. The water quality score was 92 percent and the LTA was

considered within the NRV.

	 GDEs: Three GDE assessments had been completed in this LTA:

Antelope/Smiley Meadow, Smiley Mountain Spring 1, and Smiley Mountain

Spring 2. Photos showed major impacts from grazing to these GDEs

including erosion, hummocking, and drying. Nevertheless, the PFC reports

indicated that water quality was sufficient to support riparian-wetland

plants and that no accumulation of chemicals affecting plant productivity

or composition was apparent. This is a large LTA and without additional

assessments there was insufficient information to evaluate GDE water

quality in 50G.
U.S. Forest Service RMRS GTR-394. 2019. 128

50M—Glacial Troughlands in Mixed Geology

	 Surface water systems: The level of all stressors in this LTA was

relatively low. There were no macroinvertebrate community, temperature,

or fine sediment data for this LTA. Without additional indicators, there was

insufficient information to evaluate the status of water quality in this LTA.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 50M.

50Q—Glacial Troughlands in Quartzite

	 Surface water systems: The level of stressors in this LTA was relatively

low. The macroinvertebrate community, average stream temperature, and fine

sediment values were comparable to reference conditions. The percentage

of impaired streams was slightly greater than reference conditions and

the percentage of impaired waterbodies was much greater than reference

conditions. The water quality score was 76 percent and the LTA was

considered within the NRV.

	 GDEs: Two GDE assessments had been completed in this LTA: Lee

Creek-Big Eightmile and Deer Park-North Fork. Both sites had some peat

accumulation but do not otherwise exhibit fen characteristics. The PFC

reports indicated that changes in water quality were not affecting the system,

but without additional assessments there was insufficient information to

evaluate the status of GDE water quality in 50Q.

50S—Glacial Troughlands in Sedimentary Bedrock

	 Surface water systems: The primary stressor in this LTA was grazing; due

to the prime forage in valley bottoms, domestic livestock and wildlife tend to

concentrate in riparian areas (SCNF 2004). There were no macroinvertebrate

community, temperature, or fine sediment data for this LTA. There were no

impaired waterbodies, but the percentage of impaired streams was slightly

greater than reference conditions. Without additional indicators there was

insufficient information to evaluate the status of water quality in this LTA.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 50S.

50V—Glacial Troughlands in Volcanics

	 Surface water systems: The level of stressors in this LTA was relatively

low. The macroinvertebrate community, average stream temperature,

and median substrate size were comparable to reference conditions. The

percentage of impaired streams was slightly greater than reference conditions

and the percentage of impaired waterbodies was much greater than reference

conditions. The water quality score was 76 percent and the LTA was

considered within the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 50V.
U.S. Forest Service RMRS GTR-394. 2019. 129

60G—Strongly Glaciated Lands in Granite

	 Surface water systems: The level of all stressors in this LTA was

relatively low. There were no macroinvertebrate community, temperature,

or fine sediment data for this LTA. There were no impaired streams, but

the percentage of impaired waterbodies was much greater than reference

conditions. However, without additional indicators there was insufficient 

information to evaluate the status of water quality in this LTA.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 60G.

60M—Strongly Glaciated Lands in Mixed Geology

	 Surface water systems: The primary stressor in this LTA was grazing.

There were no macroinvertebrate, temperature, or median substrate size

data for this LTA. Without additional indicators, there was insufficient 

information to evaluate the status of water quality in this LTA.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 60M.

60Q—Strongly Glaciated Lands in Quartzite

	 Surface water systems: The primary stressor in this LTA was grazing.

The macroinvertebrate community, average stream temperature, and median

substrate size were comparable to reference conditions. The percentage

of impaired streams was slightly greater than reference conditions and

the percentage of impaired waterbodies was much greater than reference

conditions. The water quality score was 76 percent and the LTA was

considered within the NRV.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 60Q.

60S—Strongly Glaciated Lands in Sedimentary Rocks

	 Surface water systems: The primary stressor in this LTA was grazing.

There were no macroinvertebrate community, temperature, or median

substrate size data for this LTA. The percentage of impaired streams and

the percentage of impaired waterbodies were slightly greater than reference

conditions. However, without additional indicators there was insufficient 

information to evaluate the status of water quality in this LTA.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 60S.
U.S. Forest Service RMRS GTR-394. 2019. 130

60V—Strongly Glaciated Lands in Volcanics

	 Surface water systems: The primary stressor in this LTA was grazing

and the level of other stressors were relatively low. There were no

macroinvertebrate community, temperature, or median substrate size data

for this LTA. The percentage of impaired streams was slightly greater than

reference conditions and the percentage of impaired waterbodies was much

greater than reference conditions. However, without additional indicators

there was insufficient information to evaluate the status of water quality in

this LTA.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 60V.

70Q—Dissected Foothill Lands in Quartzite

	 Surface water systems: The stressors in this LTA included mining and

grazing. There were no macroinvertebrate community, temperature, or

median substrate size data for this LTA. There were no impaired waterbodies,

but the percentage of impaired streams was slightly greater than reference

conditions. However, without additional indicators, there was insufficient 

information to evaluate the status of water quality in this LTA.

	 GDEs: No GDE assessments had been completed in this LTA. There was

insufficient information to evaluate the status of GDE water quality in 70Q.

70S—Dissected Foothill Lands in Sedimentary Bedrock

	 Surface water systems: The stressors in this LTA included grazing

and roads, particularly those located within the floodplain. There were no

macroinvertebrate community or temperature data available in this LTA.

There were no impaired water bodies, but the percentage of impaired streams

was much greater than reference conditions. Additionally, the median

substrate size was moderately altered from reference conditions. However,

without additional indicators there was insufficient information to evaluate

the status of water quality in this LTA.

	 GDEs: Two GDE assessments had been completed in this LTA: Spring

Hill and Sawmill Canyon/Head of Left Fork. The Spring Hill report noted

point source pollution from cattle and that changes in water quality, including

increased temperature, had affected the GDE. The Sawmill Canyon report

also noted impacts from livestock to the GDE, but water quality was

sufficient to support riparian-wetland plants. Without additional PFC reports,

there was insufficient information to evaluate the status of GDE water

quality in 70S.
U.S. Forest Service RMRS GTR-394. 2019. 131

70V—Dissected Foothill Lands in Volcanics

	 Surface water systems: The stressors in this LTA included grazing,

roads, and recreation, particularly camp sites located within the floodplain.

The macroinvertebrate community was substantially altered from reference

sites. The median substrate size was slightly less than reference sites. The

percentage of impaired streams was also slightly greater than reference

conditions, but no waterbodies were impaired. The water quality score was

60 percent and the LTA was considered moderately altered from the NRV.

	 GDEs: Forest staff had completed 27 GDE Assessments in this LTA:

Leadbelt/Deer Creek Trough, Leadbelt/Deer Creek Pond, Deer Creek Pond

Site 3, Deer Creek Pond Site 4, Horsethief Pond Site 5, Horsethief Pond

Site 6, Horsethief Pond Site 7, Horsethief Pond Site 8, Horsethief Pond Site

9, Big Buck Spring, Dry Fork Site 1, Dry Fork Unit, Leadbelt Pasture 1,

Leadbelt Pasture 2, Leadbelt Pasture 3, Leadbelt Creek Unit, Lee CreekWalters Unit, Spring Hill Site 1, Spring Hill Site 2, Spring Hill Site 4, Spring

Hill Site 5, Spring Hill Site 9, Spring Hill Site 11, Spring Hill Site 12, Spring

Hill Site 15a, Spring Hill Site 15b, and Upper Camp Unit. Of these, Lee

Creek-Walters Unit, Spring Hill Site 5, and Spring Hill Site 12 exhibited fen

characteristics. Nearly all the reports indicated that livestock grazing was

negatively impacting the GDE sites and one-third of the assessments noted

that changes in water quality were affecting the GDE. We concluded that

GDE water quality in this LTA was moderately altered from the NRV.

VB—Valley Bottom

	 Surface water systems: The stressors in this LTA included mining

and recreation. Despite these stressors, the macroinvertebrate community,

average stream temperature, and median substrate size were comparable

to reference conditions. The percentage of impaired streams was slightly

greater than reference conditions and the percentage of impaired waterbodies

was much greater than reference conditions. The water quality score was 76

percent and this LTA was considered within the NRV.

	 GDEs: No GDE assessments have been completed in this LTA. There

was insufficient information to evaluate the status of GDE water quality

in VB.

Salmon-Challis National Forest [SCNF]. 2004. Landtype association and

landtypes of the Salmon-Challis National Forest. Unpublished report on

file with: U.S. Department of Agriculture, Forest Service, Salmon-Challis

National Forest, Salmon, ID.

Reference
U.S. Forest Service RMRS GTR-394. 2019. 132

Appendix E—Channel and Floodplain Dynamics

Indicator

Little or no alteration 

(5 points)

Moderate alteration 

(3 points)

High alteration 

(1 point)

Floodplain acres/stream mile >9.97 7.76 < x < 9.97 <7.76

Sinuosity >1.08 0.81 < x < 1.08 <0.81

Bank stability >95.2 88.1 < x < 95.2 <88.1

Bank angle <120 120 < x < 148.5 >148.5

Large wood frequency >173.6 50 < x < 173.6 <50

Large wood volume >34.6 10 < x < 34.6 <10

Wildfire disturbance <10% 10% < x < 20% >20%

Wetland rating >70 60 < x < 70 <60

Table E1—Scoring for indicators of channel and floodplain dynamics within each LTA.

Methods 	 We scored nine indicators for channel and floodplain dynamics based

on whether they showed evidence of little or no, moderate, or substantial

alteration from reference conditions within the Frank Church-River of

No Return and Jim McClure-Jerry Peak Wildernesses. If the land type

associations (LTA) had little or no alteration, it was given a score of 5;

moderate alteration was given a score of 3; substantial alteration was given

a score of 1 (table E1). The scores for each LTA were summed and divided

by the potential total to give a percentage rating for each association. LTAs

were considered within the natural range of variation (NRV) for channel and

floodplain dynamics if the index was greater than 75 percent; moderately

altered from the NRV if the index was between 60 percent and 75 percent;

outside the NRV if the index was less than 60 percent.
U.S. Forest Service RMRS GTR-394. 2019. 133

10G—Steep Canyonlands in Granite

	 This LTA includes side slopes and a range of valley bottoms that may

be narrow with a stream actively cutting its channel through bedrock or

wide with a stream meandering across depositional material (SCNF 2004).

Debris slides are a common and natural disturbance to stream channels in

10G. Streams in this association tend to be very short with extremely steep

gradients (SCNF 2004). There is little forage production in this LTA and

the steep slopes tend to limit grazing to the flatter valley bottoms. The steep

terrain also limits the development of floodplains and riparian zones, as most

valley bottoms are mostly xeric with small mesic sites that tend to produce

Engelmann spruce and Douglas-fir (SCNF 2004). Stressors to channel and

floodplain dynamics in this LTA included mining, trails within the floodplain,

and invasive species. Despite these stressors, floodplain acres/stream

mile, sinuosity, bank stability, bank angle, large wood frequency, wildfire

disturbance, and wetland rating were all comparable to reference conditions.

The volume of large wood in 10G was slightly altered from reference sites.

Overall, the channel and floodplain dynamics index was 95 percent and 10G

was considered within its NRV for channel and floodplain dynamics.

10M—Steep Canyonlands in Mixed Geology

	 This is a very small LTA with no information available on its features or

typical channel structure. The levels of all stressors to channel and floodplain

dynamics were relatively low. There was insufficient information to

evaluate the status of channel and floodplain dynamics in this LTA because

there were no monitoring sites.

10Q—Steep Canyonlands in Quartzite

	 This LTA includes side slopes and a range of valley bottoms that may be

narrow with a stream actively cutting through bedrock or wide with a stream

meandering across depositional material (SCNF 2004). Debris slides are a

somewhat common natural disturbance to stream channels in 10Q. Streams

in this association tend to be very short with extremely steep gradients

(SCNF 2004). There is little forage production in this LTA and the steep

slopes tend to limit grazing outside of flatter valley bottoms. The steep terrain

also limits the development of floodplains and riparian zones, as most valley

bottoms are mostly xeric (SCNF 2004). Stressors in this LTA included roads,

trails, and recreation sites located within the floodplain, mining, and invasive

species. Despite these stressors, the floodplain acres/stream mile, sinuosity,

bank stability, bank angle, large wood volume, wildfire disturbance, and

wetland rating were all comparable to reference conditions. The frequency

of large woody debris within the channel was slightly altered from reference

channels. Overall, the channel and floodplain dynamics index score was 95

percent and 10Q was considered within its NRV.

Land Type Association 

Summaries
U.S. Forest Service RMRS GTR-394. 2019. 134

10S—Steep Canyonlands in Sedimentary Bedrock

	 This LTA includes side slopes and a range of valley bottoms that may

be narrow with a stream actively cutting its channel in bedrock or wide with

a stream meandering across depositional material (SCNF 2004). Debris

slides are a somewhat common natural disturbance to stream channels in

10S. Streams in this association tend to be very short with extremely steep

gradients. There is little forage production in this LTA and the steep slopes

tend to limit grazing outside of flatter valley bottoms. The steep terrain also

limits the development of floodplains and riparian zones, as most valley

bottoms are mostly xeric with small mesic sites composed of poor quality

aspen clones (SCNF 2004). Stressors in this LTA included livestock grazing,

roads, and recreation sites within the floodplain, and invasive species.

These stressors appeared to have impacted some components of channel

structure. Floodplain acres/stream mile, sinuosity, and bank stability were all

comparable to reference conditions. Bank angle and the frequency of large

woody debris were slightly altered from reference channels. The volume

of large wood, wildfire disturbance, and the wetland rating were all highly

altered from reference conditions. Overall, the channel and floodplain

dynamics index score was 60 percent and 10S was considered moderately 

altered from the NRV.

10V—Steep Canyonlands in Volcanics

	 This LTA includes side slopes and a range of valley bottoms that may

be narrow with a stream actively cutting through bedrock or wide with a

stream meandering across depositional material (SCNF 2004). Debris slides

are a common and natural disturbance to stream channels in 10V. Streams

in this association tend to be very short with extremely steep gradients.

There is little forage production in this LTA and the steep slopes tend to limit

grazing outside of the flatter valley bottoms. The steep terrain also limits

the development of floodplains and riparian zones, as most valley bottoms

are mostly xeric (SCNF 2004). Stressors in this LTA included trails and

invasive species within the floodplains. Despite these stressors, floodplain

acres/stream mile, sinuosity, bank stability, bank angle, large wood volume,

wildfire disturbance, and wetland rating were comparable to reference

conditions. The frequency of large woody debris within the channel was

slightly altered from reference channels. Overall, the channel and floodplain

dynamics score was 95 percent and 10V was considered within the NRV.
U.S. Forest Service RMRS GTR-394. 2019. 135

20G—Mountain Slopelands in Granite

	 The streams of this LTA exist in v-shaped valleys with steep sided slopes

(SCNF 2004). Stream gradients tend to be high and riffles typically dominate

the channel. When pools do form, they are generally poor in quality. Unless

modified by beaver, channel substrates are dominated by boulder and rubble.

In some locations, wider valley bottoms have allowed for agricultural or

housing developments (SCNF 2004). The primary stressor in this LTA was

invasive species within the floodplain. Despite this stressor, floodplain acres/

stream mile, bank stability, bank angle, large wood frequency, large wood

volume, and wetland rating were all comparable to reference conditions.

Channel sinuosity was slightly altered from reference channels and wildfire

disturbance was highly altered from reference sites. Overall, the channel and

floodplain dynamics index score was 85 percent and 20G was considered

within the NRV.

20M—Mountain Slopelands in Mixed Geology

	 This is a small LTA with no information available on its features

or typical channel structure. Relative to other LTAs on the Forest, 20M

had higher densities of mines and trails within the floodplain. There was

insufficient information to evaluate the status of channel and floodplain

dynamics because there were no monitoring sites in this LTA.

20Q—Mountain Slopelands in Quartzite

	 The streams of this LTA exist in v-shaped valleys with steep sided

slopes (SCNF 2004). Stream gradients tend to be steep and riffles typically

dominate the channel. When pools do form, they are generally poor in

quality. Unless modified by beaver, channel substrates are dominated by

boulder and rubble. In some locations, wider valley bottoms have allowed

for agricultural or housing developments. Lower slopes in this association

provide good forage that relieves some grazing pressure from the valley

bottoms (SCNF 2004). Relative to other LTAs on the Forest, a large

percentage of 20Q had been harvested for timber and the percentage of

floodplain impacted by invasive species was high. In this LTA, floodplain

acres/stream mile, sinuosity, bank stability, bank angle, and wetland rating

were all comparable to reference conditions. The frequency of large woody

debris within the channel was slightly altered from reference sites. The

volume of large wood and wildfire disturbance were highly altered from

reference conditions. Overall, the channel and floodplain dynamics index

score was 75 percent and 20Q was considered moderately altered from the

NRV.
U.S. Forest Service RMRS GTR-394. 2019. 136

20S—Mountain Slopelands in Sedimentary Bedrock

	 The streams of this LTA exist in v-shaped valleys with steep sided

slopes (SCNF 2004). Stream gradients tend to be steep and riffles typically

dominate the channel. When pools form, they are generally poor in quality.

Unless modified by beaver, channel substrates are dominated by boulder

and rubble. Most streams are intermittent or ephemeral and limit the size of

riparian zones. In some locations, wider valley bottoms have allowed for

agricultural use or housing developments. Debris slides occur somewhat

frequently and are a natural disturbance to channel structure (SCNF 2004).

Relative to other LTAs on the Forest, a large percentage of 20S has active

grazing allotments and there was a greater density of roads in the floodplain;

the percentage of floodplain impacted by invasive species was high. Despite

these stressors, floodplain acres/stream mile, sinuosity, bank stability, and

bank angle were comparable to reference conditions. The frequency and

volume of large woody debris was slightly altered from reference conditions.

Wildfire disturbance and wetland rating were both highly altered from

reference sites. Overall, the channel and floodplain dynamics index score was

70 percent and 20S was considered moderately altered from the NRV.

20V—Mountain Slopelands in Volcanics

	 The streams of this LTA exist in v-shaped valleys with steep sided

slopes (SCNF 2004). Stream gradients tend to be steep and riffles typically

dominate the channel. When pools do form, they are generally poor in

quality. Unless modified by beaver, channel substrates are dominated by

boulder and rubble. Most streams are intermittent or ephemeral and limit the

size of riparian zones. In some locations, wider valley bottoms have allowed

for agricultural use or housing developments. Debris slides occur somewhat

frequently and are a natural disturbance to channel structure (SCNF 2004).

Relative to other LTAs on the Forest, a larger percentage of 20V had active

grazing allotments. Despite this stressor, floodplain acres/stream mile,

sinuosity, bank stability, and bank angle were comparable to reference

conditions. The frequency of large woody debris, volume of large woody

debris, wildfire disturbance, and wetland rating were highly altered from

reference conditions. Overall, the channel and floodplain dynamics index

score was 60 percent and 20V was considered moderately altered from the

NRV.

30G—Cryic Uplands in Granite

	 Stream development in this LTA is limited due to high rates of

percolation and the position on the landscape (SCNF 2004). Channels tend

to have more moderate gradients than glaciated lands and the substrate is

usually dominated by fine sediments. Forage is limited to valley bottoms,

commonly concentrating livestock and big game where moisture is available

(SCNF 2004). Relative to other LTAs, 30G had a larger percentage of the

floodplain affected by recreation. Despite this stressor, floodplain acres/

stream mile, sinuosity, bank stability, bank angle, volume of large woody

debris, wildfire disturbance, and wetland rating were all comparable to

reference conditions. The frequency of large woody debris within the channel

was slightly altered from reference channels. Overall, the channel and

floodplain dynamics index score was 95 percent and 30G was considered

within the NRV.
U.S. Forest Service RMRS GTR-394. 2019. 137

30M—Cryic Uplands in Mixed Geology

	 This is a small LTA with no information available on its features or

typical channel structure. Relative to other LTAs on the Forest, a large

percentage of floodplains in 30M were impacted by invasive species. There

was insufficient information to evaluate the status of channel and floodplain

dynamics because there were no monitoring sites in this LTA.

30Q—Cryic Uplands in Quartzite

	 Stream development in this LTA is limited due to high rates of

percolation and the position on the landscape (SCNF 2004). Channels tend

to have more moderate gradients than glaciated lands and the substrate is

usually dominated by fine sediments. Forage is limited to valley bottoms,

commonly concentrating livestock and big game where moisture is available

(SCNF 2004). Relative to other LTAs on the Forest, the percentage of 30Q

with active grazing and the percentage of floodplain impacted by invasive

species were both high. In this LTA, floodplain acres/stream mile, sinuosity,

bank stability, bank angle, and wetland rating were comparable to reference

conditions. The frequency of large woody debris within the channel was

slightly altered from reference channels. The volume of large woody debris

and wildfire disturbance were highly altered from reference sites. Overall, the

channel and floodplain dynamics index score was 75 percent and 30Q was

considered moderately altered from the NRV.

30S—Cryic Uplands in Sedimentary Bedrock

	 Stream development in this LTA is limited due to high rates of

percolation and the position on the landscape (SCNF 2004). Channels tend

to have more moderate gradients than glaciated lands and the substrate is

usually dominated by fine sediments. Forage is limited to valley bottoms,

commonly concentrating livestock and big game where moisture is available

(SCNF 2004). Relative to other LTAs on the Forest, the percentage of the

LTA with active grazing allotments and the floodplain road density were

high. There was insufficient information to evaluate the NRV status of

channel and floodplain dynamics because there were no monitoring sites in

this LTA.

30V—Cryic Uplands in Volcanics

	 Stream development in this LTA is limited due to high rates of

percolation and the position on the landscape (SCNF 2004). Channels

tend to have less gradient than glaciated lands and the substrate is usually

dominated by fine sediments. Forage is limited to valley bottoms, commonly

concentrating livestock and big game where moisture is available (SCNF

2004). Relative to other LTAs on the Forest, the percentage of 30V with

active grazing allotments was high. In this LTA, floodplain acres/stream

mile, sinuosity, bank stability, and large wood volume were comparable

to reference conditions. Bank stability was slightly altered from reference

sites. The frequency of large woody debris within the channel, wildfire

disturbance, and the wetland rating were highly altered from reference

conditions. Overall, the channel and floodplain dynamics index score was 65

percent and 30V was considered moderately altered from the NRV.
U.S. Forest Service RMRS GTR-394. 2019. 138

40G—Cryic Basinlands in Granite

	 Wet meadows with a water table at or near the surface are a significant

characteristic in this LTA (SCNF 2004). Streams within these meadows

typically have low gradient, meandering channels that are fragile and easily

altered by disturbance. They are especially prone to headcutting and bank

erosion. Stream substrate in this LTA is typically small gravel and fines,

with the majority of channels functioning as depositional zones. The valley

bottoms typically contain high volumes of sedges and grasses with some

willow and these areas provide the principle forage sources for cattle and

wildlife. Beavers are often found in the streams that flow through 40G

(SCNF 2004). Relative to other LTAs on the Forest, a large percentage of the

LTA had active grazing allotments and a large percentage of floodplains was

impacted by invasive species. Despite these stressors, floodplain acres/stream

mile, sinuosity, bank stability, bank angle, frequency of large woody debris,

and the wetland rating were comparable to reference conditions. The volume

of large woody debris was slightly altered from reference channels and

wildfire disturbance was highly altered. Overall, the channel and floodplain

dynamics index was 85 percent and 40G was considered within the NRV.

40Q—Cryic Basinlands in Quartzite

	 Wet meadows with a water table at or near the surface are a significant

characteristic in this LTA (SCNF 2004). Streams within these meadows

typically have low gradient, meandering channels that are fragile and

easily altered by disturbance. They are especially prone to headcutting

and bank erosion. Stream substrate in this LTA is typically small gravel

and fines, with the majority of channels functioning as depositional zones.

The valley bottoms typically contain high volumes of sedges and grasses

with some willow, and these areas provide the principle forage sources for

cattle and wildlife. Beavers are often found in the streams that flow through

40Q (SCNF 2004). Relative to other LTAs on the Forest, 40Q had a high

percentage of land with active grazing allotments and a high density of trails

within the floodplain. There was insufficient information to evaluate the

status of channel and floodplain dynamics because there were no monitoring

sites in 40Q.

40V—Cryic Basinlands in Volcanics

	 Wet meadows with a water table at or near the surface are a significant

characteristic in this LTA (SCNF 2004). Streams within these meadows

typically have low gradient, meandering channels that are fragile and easily

altered by disturbance. They are especially prone to headcutting and bank

erosion. Stream substrate in this LTA is typically small gravel and fines,

with the majority of channels functioning as depositional zones. The valley

bottoms typically contain high volumes of sedges and grasses with some

willow and these areas provide the principle forage source for cattle and

wildlife. Beavers are often found in the streams that flow through 40V

(SCNF 2004). Relative to other LTAs on the Forest, a large percentage of

40V had active grazing allotments, a large percentage had experienced timber

harvest, and mining density was high. There was insufficient information

to evaluate the NRV status of channel and floodplain dynamics because there

were no monitoring sites in 40V.
U.S. Forest Service RMRS GTR-394. 2019. 139

50G—Glacial Troughlands in Granite

	 In this LTA, streams are small, steep, high elevation, and perennial

(SCNF 2004). The channels are dominated by boulders and streambanks

are generally rated good to excellent under natural conditions. Debris

slides are a somewhat common natural disturbance to channel structure in

these lands. High quality forage used by wildlife and livestock, including

moderate to heavy volumes of forbs and grasses, are limited to moist areas

in valley bottoms and wet meadows (SCNF 2004). The level of stressors was

relatively low in this LTA and all indicators were comparable to reference

conditions. The channel and floodplain dynamics index score was 100

percent and 50G was considered within the NRV.

50M—Glacial Troughlands in Mixed Geology

	 This is a small LTA with no information available on its features

or typical channel structure. The level of stressors was relatively low.

Nevertheless, there was insufficient information to evaluate the status of

channel and floodplain dynamics because there were no monitoring sites in

this LTA.

50Q—Glacial Troughlands in Quartzite

	 In this LTA, streams are small, steep, high elevation, and perennial

(SCNF 2004). The channels are dominated by boulders and streambanks are

generally rated good to excellent under natural conditions. Debris slides are

a somewhat common natural disturbance to channel structure in these lands.

Valley bottoms are used by elk, deer, and livestock with most high-quality

forage limited to moist areas. In these areas, wet meadows have moderate to

heavy volumes of forbs and grasses (SCNF 2004). Relative to other LTAs

on the Forest, a large percentage of the floodplain was impacted by invasive

species. Despite this stressor, floodplain acres/stream mile, sinuosity, bank

stability, bank angle, frequency of large woody debris, and the wetland

rating were comparable to reference conditions. The volume of large wood

was slightly altered from reference sites and wildfire disturbance was highly

altered from reference conditions. Overall, the channel and floodplain

dynamics index score was 85 percent and 50Q was considered within the

NRV.

50S—Glacial Troughlands in Sedimentary Rocks

	 In this LTA, streams are small, steep, high elevation, and perennial

(SCNF 2004). The channels are dominated by boulders and streambanks are

generally rated good to excellent under natural conditions. Valley bottoms

are used by elk, deer, and livestock with most high-quality forage limited to

moist areas. In these areas, wet meadows have moderate to heavy volumes

of forbs and grasses (SCNF 2004). Relative to other LTAs on the Forest, a

large percentage of 50S had active grazing allotments and a large percentage

of floodplains were impacted by invasive species. There was insufficient 

information to evaluate the NRV status because there were no monitoring

sites in 50S.
U.S. Forest Service RMRS GTR-394. 2019. 140

50V—Glacial Troughlands in Volcanics

	 In this LTA, streams are small, steep, high elevation, and perennial

(SCNF 2004). The channels are dominated by boulders and streambanks

are generally rated good to excellent under natural conditions. Debris slides

are a common natural disturbance to channel structure in these lands. Valley

bottoms are used by elk, deer, and livestock with most high-quality forage

limited to moist areas. In these areas, wet meadows have moderate to heavy

volumes of forbs and grasses. Relative to other LTAs on the Forest, the level

of stressors to channel and floodplain dynamics was low. Floodplain acres/

stream mile, sinuosity, bank stability, bank angle, frequency of large wood,

volume of large wood, and the wetland rating were comparable to reference

conditions. Wildfire disturbance was highly altered from reference sites.

Overall, the channel and floodplain dynamics index score was 90 percent and

50V was considered within the NRV.

60G—Strongly Glaciated Lands in Granite

	 This is a high elevation LTA composed of cirques, cirque basins,

headwalls, and ridges (SCNF 2004). Streams in 60G are very small and

shallow. Low quality pools dominate the channels and boulders are the

primary substrate, with little rubble or fine sediment. Streambanks are

naturally in excellent condition. Talus slopes and rock outcrops are common

features in this association and debris slides are a somewhat common natural

disturbance to channel structure. Due to short growing seasons and poor

soil development, disturbance is generally longer lived in this LTA. Mesic

vegetation within the cirque basins provides forage and these areas are used

by elk during breeding season (SCNF 2004). Relative to other LTAs on the

Forest, the level of stressors to channel and floodplain dynamics was low.

However, there was insufficient information to evaluate the NRV status

because there were no monitoring sites in 60G.

60M—Strongly Glaciated Lands in Mixed Geology

	 There is no information available on this LTA’s features or typical

channel structure. Relative to other LTAs on the Forest, the percentage

of 60M with active grazing allotments is high. There was insufficient 

information to evaluate the status of channel and floodplain dynamics

because there were no monitoring sites in 60M.

60Q—Strongly Glaciated Lands in Quartzite

	 This is a high elevation LTA composed of cirques, cirque basins,

headwalls, and ridges (SCNF 2004). Streams in 60Q are very small

and shallow. Low quality pools dominate the channels and boulders are

the primary substrate, with little rubble or fine sediment. Streambanks

are naturally in excellent condition. Talus slopes and rock outcrops are

common features in this association and avalanches are a common natural
U.S. Forest Service RMRS GTR-394. 2019. 141

disturbance to channel structure. Due to short growing seasons and poor

soil development, disturbance is generally longer lived in this LTA. Mesic

vegetation within the cirque basins provides forage and these areas have high

potential for conflict between domestic and wild grazing animals (SCNF

2004). Relative to other LTAs on the Forest, a somewhat large percentage of

60Q had active grazing allotments. Floodplain acres/stream mile, sinuosity,

bank stability, and bank angle were comparable to reference conditions.

The frequency of large woody debris was slightly altered from reference

channels. The volume of large woody debris, wildfire disturbance, and the

wetland rating were all highly altered. Overall, the channel and floodplain

dynamics index score was 65 percent and 60Q was considered moderately 

altered from the NRV.

60S—Strongly Glaciated Lands in Sedimentary Bedrock

	 This is a high elevation LTA composed of cirques, cirque basins,

headwalls, and ridges (SCNF 2004). Streams in 60S are small and shallow.

Low quality pools dominate the channels and boulders are the primary

substrate, with little rubble or fine sediment. Streambanks are naturally in

excellent condition. Talus slopes and rock outcrops are common features

in this association and debris slides are a somewhat common natural

disturbance to channel structure. Due to short growing seasons and poor

soil development, disturbance is generally longer lived in this LTA. Mesic

vegetation within the cirque basins provides forage, but grazing is somewhat

limited because of steep slopes and access difficulty. Water and mesic

vegetation in the basins attract elk during the summer and breeding season

(SCNF 2004). Relative to other LTAs on the Forest, a large percentage of

the land in 60S was open to grazing. There was insufficient information to

evaluate the NRV status of channel and floodplain dynamics because there

were no monitoring sites in this LTA.

60V—Strongly Glaciated Lands in Volcanic

	 This is a high elevation LTA composed of cirques, cirque basins,

headwalls, and ridges (SCNF 2004). Streams in 60V are small and shallow.

Low quality pools dominate the channels and boulders are the primary

substrate, with little rubble or fine sediment. Streambanks are naturally in

excellent condition. Talus slopes and rock outcrops are common features

in this association and debris slides and avalanches are a common natural

disturbance to channel structure. Due to short growing seasons and poor

soil development, disturbance is generally longer lived in this LTA. Mesic

vegetation within the cirque basins provides forage and these areas are

used by elk during breeding season (SCNF 2004). Relative to other LTAs

on the Forest, the percentage of 60V open to grazing was high. There

was insufficient information to evaluate the NRV status of channel and

floodplain dynamics because there were no monitoring sites in this LTA.
U.S. Forest Service RMRS GTR-394. 2019. 142

70Q—Dissected Foothill Lands in Quartzite

	 The streams in this LTA are located in modified u-shaped valleys (SCNF

2004). The channels typically have moderate gradients with substrates

composed of rubble and gravel. The pool-riffle ratio in 70Q is expected

to be good with fairly good quality pools. Streams originating in this LTA

are generally intermittent or ephemeral, limiting the extent of floodplain

development. This LTA is capable of supporting a large amount of grazing

by wild or domestic animals and is important winter range for big game

(SCNF 2004). Relative to other LTAs on the Forest, a large percentage of

70Q was open to grazing; mine density and diversion density were high; and

a large percentage of the floodplain was impacted by invasive species. There

was insufficient information to evaluate the NRV status of channel and

floodplain dynamics because there were no monitoring sites 70Q.

70S—Dissected Foothill Lands in Sedimentary Bedrock

	 The streams in this LTA are located in modified u-shaped valleys (SCNF

2004). The channels typically have moderate gradients with substrates

composed of rubble and gravel. The pool-riffle ratio in 70S is expected

to be good with fairly good quality pools. Streams originating in this LTA

are generally intermittent or ephemeral, limiting the extent of floodplain

development. The perennial streams in 70S can support good fish populations

with important spawning and nursery areas for anadromous fish. This LTA is

capable of supporting a large amount of grazing by wild or domestic animals

and is important winter range for big game (SCNF 2004). Relative to other

LTAs, a large percentage of 70S was open to grazing and the road density

within the floodplain was high. There was insufficient information to

evaluate the NRV status because there were no monitoring sites in 70S.

70V—Dissected Foothill Lands in Volcanics

	 The streams in this LTA are located in modified u-shaped valleys (SCNF

2004). The channels typically have moderate gradients with substrates

composed of rubble and gravel. The pool-riffle ratio in 70V is expected to be

good with fairly good quality pools. Streams originating in 70V are generally

intermittent or ephemeral, limiting the extent of floodplain development.

This LTA provides suitable forage for domestic sheep, but slopes are

generally too steep to support cattle grazing (SCNF 2004). Relative to

other LTAs on the Forest, a large percentage of 70V was open to grazing;

there was a high density of roads and trails in the floodplain; and a large

percentage of floodplains were impacted by recreation sites. In this LTA,

floodplain acres/stream mile, sinuosity, bank angle, wildfire disturbance,

and the wetland rating were all comparable to reference conditions. Bank

stability and the volume of large woody debris were slightly altered from

reference conditions. The frequency of large woody debris within the channel

was highly altered from reference sites. Overall, the channel and floodplain

dynamics index score was 80 percent and 70V was considered within the

NRV.
U.S. Forest Service RMRS GTR-394. 2019. 143

VB—Valley Bottom

	 This LTA includes the valley bottoms of drainages across the Forest.

There is no information available on the geology or typical channel features,

but it is likely primarily composed of alluvium. Approximately 24 percent

of this LTA was floodplain, more than any other LTA on the Forest. Relative

to other LTAs on the Forest, there were high densities of roads, mines,

diversions, and trails in VB; there was a high percentage of floodplains

impacted by recreation sites and invasive species. In this LTA, floodplain

acres, sinuosity, bank stability, and bank angle were comparable to reference

conditions. The frequency and volume of large woody debris were slightly

altered from reference channels. Wildfire disturbance and the wetland rating

were highly altered from reference conditions. Overall, the channel and

floodplain dynamics index score was 70 percent and VB was considered

moderately altered from the NRV.

Salmon-Challis National Forest [SCNF]. 2004. Landtype association and

landtypes of the Salmon-Challis National Forest. Unpublished report on

file with: U.S. Department of Agriculture, Forest Service, Salmon-Challis

National Forest, Salmon, ID.

Reference
U.S. Forest Service RMRS GTR-394. 2019. 144

Appendix F—Condition of Spring Runout Channel

Methods

Land Type Association 

(LTA) Summaries

	 To evaluate the condition of spring runout channels, we used proper

functioning condition (PFC) reports completed by Salmon-Challis National

Forest (SCNF) staff. These assessments included information on whether

the runout channel was functioning naturally or was entrenched, eroded, or

otherwise substantially altered. The reports also included information on

the potential stressors to the condition of spring runout channels, including

hydrologic alterations, soil alterations, presence of structures, recreation

effects, or animal effects. We summarized these reports and used best

professional judgment to determine the natural range of variation (NRV)

status of water quality at groundwater-dependent ecosystems (GDEs).

	 No GDE assessments had been completed and there was therefore

insufficient information to evaluate the condition of spring runout channels

in the following LTAs:

10G—Steep Canyonlands in Granite

10M—Steep Canyonlands in Mixed Geology

10Q—Steep Canyonlands in Quartzite

10S—Steep Canyonlands in Sedimentary Rocks

10V—Steep Canyonlands in Volcanics

20G—Mountain Slopelands in Granite

20M—Mountain Slopelands in Mixed Geology

20S—Mountain Slopelands in Sedimentary Rocks

30G—Cryic Uplands in Granite

30M—Cryic Uplands in Mixed

30Q—Cryic Uplands in Quartzite

30V—Cryic Uplands in Volcanics

40G—Cryic Basinlands in Granite

40Q—Cryic Basinlands in Quartzite

40V—Cryic Basinlands in Volcanics

50M—Glacial Troughlands in Mixed Geology

50S—Glacial Troughlands in Sedimentary Rocks

50V—Glacial Troughlands in Volcanics

60G—Strongly Glaciated Lands in Granite

60M—Strongly Glaciated Lands in Mixed Geology

60Q—Strongly Glaciated Lands in Quartzite

60S—Strongly Glaciated Lands in Sedimentary Rocks

60V—Strongly Glaciated Lands in Volcanic

70Q—Dissected Foothill Lands in Quartzite

VB—Valley Bottom
U.S. Forest Service RMRS GTR-394. 2019. 145

20Q—Mountain Slopelands in Quartzite

	 A single GDE assessment (Cove Creek-Cove Creek) was completed at

a spring in this LTA in 2015. The report documented that there was water

flowing in channels, but that unnatural entrenchment and channelization had

occurred, causing the site to go dry. Grazing wild animals and livestock was

noted to be causing erosion and ground disturbance that had disturbed the

spring runout channel. This site was described as functional-at-risk with a

downward trend. This LTA is large with only one GDE assessment available.

Therefore, there was insufficient information to evaluate the condition of

spring runout channels in 20Q.

20V—Mountain Slopelands in Volcanics

	 Seventeen GDE assessments had been completed for this LTA. Thirteen

of these PFC reports indicated the systems were functional-at-risk. The

majority of assessments reported negative impacts to spring runout channels

from grazing. Trailing, trampling, and bank shearing from hooves had caused

erosion and channelization. Additionally, some spring channels in this LTA

were affected by diversions, ditches, and roads/trails. Most of the reports did

not indicate trends of the GDE systems. Overall, PFC reports suggested that

there were significant impacts and the condition of spring runout channel in

20V was considered outside the NRV.

30S—Cryic Uplands in Sedimentary Rocks

	 A single GDE assessment had been completed by Forest staff in this

LTA: Timber Creek-Trail Creek. This report noted minor impacts from

grazing by wild animals. Nevertheless, the spring runout channel was

functioning naturally and was not entrenched, eroded, or otherwise altered.

The site was categorized as properly functioning. However, without

additional assessments, there was insufficient information to evaluate the

condition of spring runout channels in this LTA.

50G—Glacial Troughlands in Granite

	 Three GDE assessments had been completed by Forest staff in this LTA:

Smiley Mountain Spring 1, Smiley Mountain Spring 2, and Antelope/Smiley

Meadow. All three reports indicated that spring flow paths had been altered

by heavy cattle use. However, this is a large LTA and without additional

assessments there was insufficient information to evaluate the NRV status

of spring runout channels.

50Q—Glacial Troughlands in Quartzite

	 Two GDE assessments had been completed by Forest staff in this LTA:

Lee Creek-Big Eightmile and Deer Park-North Fork. The Big Eightmile site

exhibited fen characteristics and did not have any spring runout channels

present. The runout channel at the Deer Park-North Fork was entrenched,

eroded, or otherwise substantially altered as a result of livestock use. The

report indicated channel erosion, excavation of the spring source, and a

nonfunctional trough as contributing to a functional-at-risk system with

a static to downward trend. Without additional assessments there was

insufficient information to evaluate the NRV status of spring runout

channels in this LTA.
U.S. Forest Service RMRS GTR-394. 2019. 146

70S—Dissected Foothill Lands in Sedimentary Rocks

	 Two GDE assessments had been completed in this LTA by SCNF staff:

Spring Hill Site 3 and Sawmill Canyon/Head of Left Fork. Both reports

indicated major impacts to spring runout channels from livestock grazing.

The natural flow paths at the Sawmill Canyon site had been altered by

hoof action. Historic headcuts were present, but they were revegetated

and the seep complex was determined to be trending upward. The spring

runout channel at the Spring Hill Site was entrenched, eroded, or otherwise

substantially altered. Without additional assessments, there was insufficient 

information to evaluate the NRV status of spring runout channels in this

LTA.

70V—Dissected Foothill Lands in Volcanics

	 Twenty-seven GDE assessments had been completed by SCNF staff in

this LTA. Of these, nine reports indicated channel erosion was occurring

at the site. Fifteen of the assessments indicated that either the natural flow

pattern had been altered by disturbance or that the runout channel was

entrenched, eroded, or otherwise substantially altered. Thirteen of the

sites showed impacts such as trailing or trampling from livestock and wild

animal grazing. One report recorded entrenched channels where water used

to dissipate across the associated meadow. Anthropogenic effects were

impacting the condition of spring runout channels at more than half of the

sites assessed in this LTA. The condition of spring runout channels in 70V

was considered to be outside the NRV.
U.S. Forest Service RMRS GTR-394. 2019. 147

Methods

Appendix G—Composition and Condition of Riparian Ecosystems

Indicator

Data 

source

Little or no alteration 

(5 points)

Moderate alteration 

(3 Points)

High alteration 

(1 Point)

Percent conifer encroachment R-CAT <15 15–20 >20

Percent upland encroachment R-CAT <10 10–15 >15

Percent replacement by introduced vegetation R-CAT <1 1–2 >2

Riparian condition WCF Majority of LTA 

in good condition

Majority of LTA 

in fair condition

Majority of LTA 

in poor condition

Percent reach native cover PIBO >75 50–75 <50

Percent reach alien cover PIBO <1 1–2 >2

Percent greenline cover PIBO >80 70–80 <70

Percent effective ground cover PIBO >90 80–90 <80

Cross-section wetland index PIBO >50 40–50 <40

Table G1—Criteria for assigning riparian distribution and connectivity scores, which were used calculate an index value for 

each LTA. 

	 Because of the inherently complicated nature of riparian composition and

condition and the shortage of sampling sites in many land type associations

(LTAs), we used a combination of quantitative methods and professional

judgment in determining natural range of variation (NRV) status. We

calculated indices of composition and condition using spatial and fieldsampled datasets, some of which were available for managed and reference

(Wilderness) sites.

1.	 We calculated an index from spatial data by combining estimates of

conifer encroachment, upland vegetation encroachment, replacement

by introduced vegetation (these three from Riparian Condition

Assessment Tool [R-CAT] results) and riparian and wetland condition

(from Watershed Condition Framework [WCF]). We gave each of

these four indicators a score of 5, 3, or 1 using the criteria in table G1,

which were informed by means from reference areas. We summed

these scores for each LTA and divided by their potential total to obtain

a final index value ranging between 0 and 100 percent.

2.	 We calculated an index from Pacfish-Infish biological opinion

(PIBO) data using native cover, reach alien cover, greenline cover,

effective ground cover, and wetland index. Because PIBO variables

have been remeasured over several years at most stream sites, we

calculated index scores from the first measurement year and from the

most recent measurement year. Criteria for scoring were informed by
U.S. Forest Service RMRS GTR-394. 2019. 148

Land Type Association 

Summaries

means from sampling sites in reference areas. We divided cumulative

scores by their potential total to obtain a final index value ranging

between 0 and 100 percent.

3.	 We examined trends in Aquatic Zone Analysis Rating (AZAR) scores

and other information to develop a qualitative assessment of the

condition of riparian community types present in each LTA.

4.	 We considered the above results to determine whether riparian

composition and condition is within the NRV, outside of the NRV, or

moderately altered in each LTA.

10G—Steep Canyonlands in Granite

	 Over 95 percent of perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Approximately 5 miles of perennial

streams occurred in unconfined valley bottoms, which can contain tall

deciduous, willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was

fairly high (70 percent) because of moderate levels of upland encroachment

and high levels of introduced species. Vegetation data were collected on 14

occasions at six PIBO monitoring sites. Composition and condition index

values from the first and most recent measurements were high (92 percent).

Most of the LTA (60 percent) was in Wilderness and less than 10 percent

was within active grazing allotments. There were nine watershed monitoring

sites in the LTA. The most recent mean AZAR score (82.4) was greater than

the long-term mean (81.7) and the 5-year mean (79.5), indicating improving

riparian conditions at these managed sites. Given the above information, we

determined that 10G was within its NRV because, though encroachment and

invasive species were prevalent, condition indicators were relatively high.

10M—Steep Canyonlands in Mixed Geology

	 This is a very small LTA with all perennial streams in confined settings

with riparian communities typically characterized by conifer and low

deciduous tree dominance groups. The composition and condition index

derived from spatial data was high (90 percent) with moderate levels of

conifer encroachment. This LTA was entirely within Wilderness and there

were no active grazing allotments. There was insufficient information to

determine NRV status at 10M because field data are unavailable.

10Q—Steep Canyonlands in Quartzite

	 Over 90 percent of perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and low

deciduous tree dominance groups. Less than 5 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.
U.S. Forest Service RMRS GTR-394. 2019. 149

	 The composition and condition index derived from spatial data was

fair (60 percent) because of high levels of conifer encroachment, moderate

levels of introduced species, and fair riparian and wetland condition.

Vegetation data were collected on 10 occasions at four PIBO monitoring

sites. Composition and condition index values from the first and most

recent measurements were fairly high (84 percent). Most of the LTA was in

managed areas (82 percent) and active allotments (56 percent). There were

10 watershed monitoring sites in the LTA. The most recent mean AZAR

score (68.7) is less than the long-term mean (80.7) and the 5-year mean

(78.3), indicating declining riparian conditions in these managed sites.

	 Given the above information, we determined that 10Q was within the

NRV because, though AZAR scores were decreasing, there were fairly high

composition and condition index values from managed PIBO sites.

10S—Steep Canyonlands in Sedimentary Bedrock

	 Nearly 90 percent of perennial stream miles in this LTA were in confined

settings, with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Less than 2 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was

fairly low (50 percent) as a result of high levels of conifer and upland

encroachment and fair riparian and wetland condition. Vegetation data were

collected on nine occasions at three PIBO monitoring sites. Composition

and condition index values from the first and most recent measurements

were fairly low and fair, respectively (44 percent and 68 percent). The LTA

was entirely in managed areas and active grazing allotments, but riparian

areas may be inaccessible to livestock due to steep topography. There were

three watershed monitoring sites in the LTA. The most recent mean AZAR

score (80.7) was greater than the long-term mean (76.8) and the 5-year mean

(79.3), indicating improving riparian conditions.

	 Given the above information, we determined that composition and

condition at 10S was moderately altered, but low index values from spatial

data and PIBO sites could be addressed through management changes.

10V—Steep Canyonlands in Volcanics

	 Over 90 percent of perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Over 5 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.
U.S. Forest Service RMRS GTR-394. 2019. 150

	 The composition and condition index derived from spatial data was low

(50 percent), because of fair riparian and wetland condition, moderate levels

of conifer and upland encroachment, and high levels of introduced species.

Vegetation data were collected on 20 occasions at eight PIBO monitoring

sites. Composition and condition index values from the first and most recent

measurements were fair and fairly high, respectively (68 percent and 76

percent). Most (66 percent) of the LTA was in Wilderness and 35 percent was

in active grazing allotments. Riparian areas may be inaccessible to livestock

due to steep topography. Composition and condition were influenced by

beaver activity at one PIBO site. Another site was burned by wildfires but

deciduous trees had recovered via resprouting. There were five watershed

monitoring sites in the LTA. The most recent mean AZAR score (82.6) was

greater than the long-term mean (81.1) and the 5-year mean (80.3), indicating

improving riparian conditions at managed sites. Given the above information,

we determined that 10V was moderately altered with increasing PIBO

index values and AZAR scores.

20G—Mountain Slopelands in Granite

	 Over 95 percent of perennial stream miles in this LTA were in confined

settings, with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Less than 5 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was

fair (60 percent) as a result of moderate levels of conifer and upland

encroachment and high levels of introduced species. Vegetation data were

collected on 15 occasions at three PIBO monitoring sites. Composition and

condition index values from the first and most recent measurements were fair

and high, respectively (68 percent and 100 percent). Most (56 percent) of the

LTA was in Wilderness and 21 percent was in active allotments. There were

three watershed monitoring sites in the LTA. The most recent mean AZAR

score (79.7) was less than the long-term mean (83.1) and the 5-year mean

(83.2), indicating declining riparian conditions at managed sites. Given the

above information, we determined that 20G was within the NRV because of

relatively high PIBO index values and AZAR scores.

20M—Mountain Slopelands in Mixed Geology 

	 This is a very small LTA with all perennial stream miles in confined

settings with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. The composition and condition

index derived from spatial data was fair (70 percent) with moderate levels

of conifer encroachment and high levels of introduced vegetation. This

LTA was entirely in Wilderness and outside of active allotments. There was

insufficient information to determine NRV status at 20M because field data

were unavailable.
U.S. Forest Service RMRS GTR-394. 2019. 151

20Q—Mountain Slopelands in Quartzite

	 Over 95 percent of perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Over 5 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data is fairly

high (70 percent) with high levels of conifer encroachment and fair riparian

and wetland condition. Vegetation data were collected on 31 occasions at

11 PIBO monitoring sites. Composition and condition index values from

the first and most recent measurements were high (92 percent). Most (83

percent) of the LTA was in managed areas and active allotments (57 percent).

There were 15 watershed monitoring sites in the LTA. The most recent mean

AZAR score (82.5) was similar to the long-term mean (82.3) and the 5-year

mean (83.4), indicating stable conditions in managed areas. Given the above

information, we determined that 20Q was within its NRV because of the high

spatial data index, PIBO index values, and AZAR scores.

20S—Mountain Slopelands in Sedimentary Bedrock

	 Most (70 percent) perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Over 10 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was

fair (60 percent) with high levels of upland encroachment, moderate

levels of conifer encroachment, and fair riparian and wetland condition.

Vegetation data were collected on six occasions at two PIBO monitoring

sites. Composition and condition index values from the first and most

recent measurements were fair and fairly high, respectively (60 percent

and 76 percent). Most of the LTA was in managed areas (98 percent) and

active allotments (93 percent). Livestock effects were apparent at a best

management practices (BMP) monitoring site at Canyon Creek, but grazing

greenline composition and woody plant age class were improving. Given the

above information, we determined that 20S was moderately altered with

fair but improving conditions at PIBO and BMP sites.

20V—Mountain Slopelands in Volcanics

	 Over 90 percent of perennial stream miles in this LTA were in confined

settings, with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Over 30 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.
U.S. Forest Service RMRS GTR-394. 2019. 152

	 The composition and condition index derived from spatial data was low

(50 percent) because of fair riparian and wetland condition, moderate levels

of conifer encroachment and introduced species, and high levels of upland

encroachment. Vegetation data were collected on 90 occasions at 32 PIBO

monitoring sites. Composition and condition index values from the first and

most recent measurements were fair and fairly high, respectively (60 percent

and 76 percent). Most of the LTA was in managed areas (68 percent) and

active allotments (75 percent). Composition and condition were influenced

by beaver activity at three or more PIBO sites.

	 There were 24 watershed monitoring sites in the LTA. The most recent

mean AZAR score (72.4) was less than the long-term mean (79.9) and the 5-

year mean (74.2), indicating declining riparian conditions in managed areas.

Livestock effects were apparent at several BMP monitoring sites. Conditions

were improving at these sites, but desired conditions had not been met. Given

the above information, we determined that 20V was moderately altered with

improving PIBO index values.

30G—Cryic Uplands in Granite

	 Over 90 percent of perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Over 10 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was high

(100 percent). Vegetation data were collected on three occasions at one PIBO

monitoring site. Composition and condition index values from the first and

most recent measurements were fairly high and fair, respectively (76 percent

and 68 percent). Most (54 percent) of the LTA was in managed areas and

31 percent was in active allotments. There was insufficient information to

determine NRV status at 30G because field data were limited to one PIBO

site.

30M—Cryic Uplands in Mixed Geology

	 This is a very small LTA with all perennial stream miles in confined

settings with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. The composition and condition index

derived from the spatial data was high (100 percent). Nearly all of the LTA

(>99 percent) was in Wilderness and only 2 percent was in active allotments.

There was insufficient information to determine NRV status at 30M because

field data were unavailable.

30Q—Cryic Uplands in Quartzite

	 Over 90 percent of perennial stream miles in this LTA were in confined

settings, with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Nearly 5 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.
U.S. Forest Service RMRS GTR-394. 2019. 153

	 The composition and condition index derived from spatial data was

moderate (70 percent) because of fair riparian and wetland condition and

high levels of conifer encroachment. Vegetation data were collected on 10

occasions at four PIBO monitoring sites. Composition and condition index

values from the first and most recent measurements were high (100 percent

and 92 percent). Most of the LTA was in managed areas (95 percent) and

active allotments (71 percent). There were six watershed monitoring sites

in the LTA. The most recent mean AZAR score (85.7) was greater than the

long-term mean (82.1) and the 5-year mean (83.6), indicating improving

riparian conditions. Given the above information, we determined that 30Q

was within the NRV because of high PIBO index scores and AZAR scores.

30S—Cryic Uplands in Sedimentary Bedrock

	 Over 90 percent of perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Less than 1 mile of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was

moderate (60 percent) as a result of fair riparian and wetland condition, high

levels of conifer encroachment, and moderate levels of upland encroachment.

This LTA was entirely in managed areas almost entirely in active allotments

(98 percent). There was insufficient information to determine NRV status at

30S because field data were unavailable.

30V—Cryic Uplands in Volcanics

	 Over 95 percent of perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Nearly 5 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was fairly

high (80 percent), with fair riparian and wetland condition and moderate

levels of conifer encroachment. Vegetation data were collected on six

occasions at three PIBO monitoring sites. Composition and condition index

values from the first and most recent measurements were low (44 percent and

36 percent). Most of the LTA was in managed areas (69 percent) and active

allotments (62 percent). There was one watershed monitoring site in the LTA.

The most recent AZAR score (77.0) was less than the long-term mean (82.7)

and the 5-year mean (84.5), indicating declining riparian conditions at this

managed site. Given the above information, we determined that 30V was

moderately altered, but low PIBO index and AZAR scores can be addressed

through management changes.
U.S. Forest Service RMRS GTR-394. 2019. 154

40G—Cryic Basinlands in Granite

	 Over 90 percent of perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and low

deciduous tree dominance groups. Less than 5 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was high

(90 percent) with fair riparian and wetland condition. Vegetation data were

collected on three occasions at one PIBO monitoring site. Composition and

condition index values from the first and most recent measurements were fair

(68 percent). Most of the LTA was in managed areas (76 percent) and active

allotments (75 percent). There was insufficient information to determine

NRV status at 40G because field data were limited to one PIBO site.

40Q—Cryic Basinlands in Quartzite

	 Over 90 percent of perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Less than 1 mile of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was high

(80 percent), with fair riparian and wetland condition and moderate levels of

conifer encroachment. This LTA was entirely in managed areas and active

allotments. There was insufficient information to determine NRV status at

40Q because field data were unavailable.

40V—Cryic Basinlands in Volcanics

	 Over 90 percent of perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and low

deciduous tree dominance groups. Less than 2 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was high

(90 percent) with fair riparian and wetland condition. This LTA was entirely

in managed areas and almost entirely in active allotments (98 percent). There

was insufficient information to determine NRV status at 40V because field

data were unavailable.

50G—Glacial Troughlands in Granite

	 Over 90 percent of perennial stream miles in this LTA were in confined

settings, with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Over 40 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.
U.S. Forest Service RMRS GTR-394. 2019. 155

	 The composition and condition index derived from spatial data was high

(90 percent) with fair riparian and wetland condition. Vegetation data were

collected on 13 occasions at five PIBO monitoring sites. Composition and

condition index values from the first and most recent measurements were fair

and high, respectively (68 percent and 100 percent). Most (55 percent) of the

LTA was in Wilderness and 47 percent was in active allotments. Given the

above information, we determined that 50G was within its NRV because of

high spatial index and PIBO index scores.

50M—Glacial Troughlands in Mixed Geology

	 This is a very small LTA with all perennial stream miles in confined

settings with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. The composition and condition

index derived from spatial data index was high (100 percent). This LTA

was entirely in Wilderness and outside of active allotments. There was

insufficient information to determine NRV status at 50M because field data

were unavailable.

50Q—Glacial Troughlands in Quartzite

	 Over 90 percent of perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Nearly 5 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was fairly

high (70 percent), with high levels of conifer encroachment and fair riparian

and wetland condition. Vegetation data were collected on three occasions

at one PIBO monitoring site. Composition and condition index values from

the first and most recent measurements were fair (68 percent). Most of the

LTA was in managed areas (87 percent) and active allotments (59 percent).

There was one watershed monitoring site in the LTA. The most recent AZAR

score (81.0) was greater than the long-term mean (69.1) and the 5-year mean

(71.3), indicating improving riparian conditions at this managed site.

	 Given the above information, we determined that 50G was moderately 

altered with fair PIBO index scores and improving AZAR scores.

50S—Glacial Troughlands in Sedimentary Bedrock

	 Over 90 percent of perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and low

deciduous tree dominance groups. Less than 2 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was

moderate (70 percent), with fair riparian and wetland condition and high

levels of conifer encroachment. Almost all of the LTA was in managed areas

(99 percent) and active allotments (97 percent). There was insufficient 

information to determine NRV status at 50S because field data were

unavailable.
U.S. Forest Service RMRS GTR-394. 2019. 156

50V—Glacial Troughlands in Volcanics

	 Over 90 percent of perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Over 5 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was fairly

high (80 percent), with fair riparian and wetland condition and moderate

levels of conifer encroachment. Vegetation data were collected on 13

occasions at two PIBO monitoring sites. Composition and condition index

values from the first and most recent measurements were fair (60 percent

and 68 percent). Most (59 percent) of the LTA was in managed areas and 45

percent was in active allotments. There were three watershed monitoring sites

in the LTA. The most recent mean AZAR score (75.0) was less than the longterm mean (81.3) and the 5-year mean (79.2), indicating declining riparian

conditions in managed areas. Given the above information, we determined

that 50V was moderately altered with improving PIBO index scores.

60G—Strongly Glaciated Lands in Granite

	 Over 90 percent of perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Over 10 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was high

(90 percent) with fair riparian and wetland condition. Most (67 percent) of

the LTA was in Wilderness and 26 percent was in active allotments. There

was insufficient information to determine NRV status at 60G because field

data were unavailable.

60M—Strongly Glaciated Lands in Mixed Geology

	 This is a very small LTA with all perennial stream miles in confined

settings, with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. The composition and condition index

derived from spatial data was high (90 percent) with fair riparian and wetland

condition. Most (74 percent) of the LTA was in managed areas and active

allotments (86 percent). There was insufficient information to determine

NRV status at 60M because field data were unavailable.

60Q—Strongly Glaciated Lands in Quartzite

	 Most (64 percent) perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Nearly 100 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.
U.S. Forest Service RMRS GTR-394. 2019. 157

	 The composition and condition index derived from spatial data was

moderate (70 percent) with fair riparian and wetland condition and moderate

levels of conifer and upland encroachment. Vegetation data were collected

on 47 occasions at 15 PIBO monitoring sites. Composition and condition

index values from the first and most recent measurements were fairly low

and fair, respectively (52 percent and 60 percent). Most of the LTA was in

managed areas (96 percent) and active allotments (63 percent). Composition

and condition were influenced by beaver activity at two or more PIBO

sites. Recreation effects were evident at a BMP site on East Fork Big Lost

River, but composition and condition otherwise indicated that management

objectives have been met. There were 11 watershed monitoring sites in the

LTA. The most recent mean AZAR score (68.7) was less than the longterm mean (72.2) and the 5-year mean (70.9), indicating declining riparian

conditions. Given the above information, we determined that 60Q was

moderately altered, but low PIBO index scores and AZAR scores could be

addressed through management changes.

60S—Strongly Glaciated Lands in Sedimentary Bedrock

	 Over 90 percent of perennial stream miles in this LTA were in confined

settings, with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Less than 5 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was

fairly high (80 percent) with fair riparian and wetland and moderate levels

of upland encroachment. This LTA was entirely in managed lands and

almost entirely in active allotments (99 percent). There was insufficient 

information to determine NRV status at 60S because field data were

unavailable.

60V—Strongly Glaciated Lands in Volcanics

	 Over 90 percent of perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and low

deciduous tree dominance groups. Less than 5 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was high

(90 percent), with fair riparian and wetland condition. Most (73 percent) of

the LTA was in managed areas and active allotments (61 percent). There was

insufficient information to determine NRV status at 60V because field data

were unavailable.
U.S. Forest Service RMRS GTR-394. 2019. 158

70Q—Dissected Foothill Lands in Quartzite

	 Most (69 percent) perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and low

deciduous tree dominance groups. Less than 2 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was

low (50 percent) because of fair riparian and wetland condition scores and

high levels of conifer and upland encroachment. This LTA was entirely

in managed lands and 84 percent was in active allotments. There was

one watershed monitoring site in the LTA. The most recent AZAR score

(72.0) was less than the long-term mean (77.5) and the 5-year mean (77.5),

indicating declining riparian conditions. There was insufficient information

to determine NRV status because field data were limited to one WMP site.

70S—Dissected Foothill Lands in Sediments

	 Nearly 90 percent of perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and low

deciduous tree dominance groups. Less than 5 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was fairly

high (70 percent), with fair riparian and wetland condition and high levels

of upland encroachment. Vegetation data were collected on three occasions

at one PIBO monitoring site. Composition and condition index values from

the first and most recent measurements were fairly high (0.84). Most (>99

percent) of the LTA was in managed areas and active allotments (93 percent).

There was insufficient information to determine NRV status because field

data were limited to one PIBO site.

70V—Dissected Foothill Lands in Volcanics

	 Over 90 percent of perennial stream miles in this LTA were in confined

settings with riparian communities typically characterized by conifer and low

deciduous tree dominance groups. Less than 5 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was

fairly high (70 percent), with fair riparian and wetland condition and high

levels of upland encroachment. Vegetation data were collected on three

occasions at one PIBO monitoring site. Composition and condition index

values from the first and most recent measurements were fairly low and

fairly high, respectively (52 percent and 84 percent). Most of the LTA was

in managed areas (99 percent) and active allotments (95 percent). There

were four watershed monitoring sites in the LTA. The most recent mean

AZAR score (82.3) was greater than the long-term mean (74.8) and the

5-year mean (81.8), indicating improving riparian conditions. Given the

above information, we determined that 70V was moderately altered with

improving PIBO index scores and AZAR scores.
U.S. Forest Service RMRS GTR-394. 2019. 159

VB—Valley Bottom

	 Most (73 percent) perennial stream miles in this LTA were in confined

settings, with riparian communities typically characterized by conifer and

low deciduous tree dominance groups. Over 200 miles of perennial streams

occurred in unconfined valley bottoms, which can contain tall deciduous,

willow, non-willow shrub, and herbaceous dominance groups.

	 The composition and condition index derived from spatial data was fairly

high (70 percent), with fair riparian and wetland condition and moderate

levels of conifer encroachment and introduced species. Vegetation data were

collected on 147 occasions at 54 PIBO monitoring sites. Composition and

condition index values from the first and most recent measurements were

fair and fairly high, respectively (68 percent and 76 percent). Most of the

LTA was in managed areas (87 percent) and active allotments (60 percent).

Composition and condition were influenced by beaver activity at five or

more PIBO sites. Several PIBO sites have been burned by wildfires, but

deciduous vegetation had recovered. There were 59 watershed monitoring

sites in the LTA. The most recent mean AZAR score (78.9) was similar to the

long-term mean (78.1) and the 5-year mean (79.4), indicating stable riparian

conditions. Given the above information, we determined that VB was

moderately altered with fair index scores and improving AZAR scores.
U.S. Forest Service RMRS GTR-394. 2019. 160

Methods

Land Type Association 

Summaries

Appendix H—Composition and Condition 

of Groundwater-Dependent Ecosystems

	 We summarized proper functioning condition (PFC) reports for each

land type associations (LTA) and used best professional judgment to

determine the natural range of variation (NRV) of composition and condition

of groundwater-dependent ecosystems (GDEs) in LTAs where at least 10

surveys were conducted.

	 No GDE assessments had been completed and there was therefore

insufficient information to evaluate the condition of spring runout channels in

the following LTAs:

10G—Steep Canyonlands in Granite

10M—Steep Canyonlands in Mixed Geology

10Q—Steep Canyonlands in Quartzite

10S—Steep Canyonlands in Sedimentary Rocks

10V—Steep Canyonlands in Volcanics

20G—Mountain Slopelands in Granite

20M— Mountain Slopelands in Mixed Geology

20S—Mountain Slopelands in Sedimentary Rocks

30G—Cryic Uplands in Granite

30M—Cryic Uplands in Mixed

30Q—Cryic Uplands in Quartzite

30S—Cryic Uplands in Sedimentary Rocks

30V—Cryic Uplands in Volcanics

40G—Cryic Basinlands in Granite

40Q—Cryic Basinlands in Quartzite

40V—Cryic Basinlands in Volcanics

50M—Glacial Troughlands in Mixed Geology

50S—Glacial Troughlands in Sedimentary Rocks

50V—Glacial Troughlands in Volcanics

60G—Strongly Glaciated Lands in Granite

60M—Strongly Glaciated Lands in Mixed Geology

60Q—Strongly Glaciated Lands in Quartzite

60S—Strongly Glaciated Lands in Sedimentary Rocks

60V—Strongly Glaciated Lands in Volcanic

70Q—Dissected Foothill Lands in Quartzite
U.S. Forest Service RMRS GTR-394. 2019. 161

20Q—Mountain Slopelands in Quartzite

	 A GDE survey was conducted at a spring site in the Lemhi Basin in

2015. The spring-fed wetland was characterized by herbaceous dominance

groups containing Poa pratensis and Phleum pratense. Sedges, rushes, and

willows were also present, but in patches. This area had become channelized

and had lost its wetland character as a result. Willows and aspens were also

impacted by herbivory. Soil had been affected by compaction, erosion, and

trails. The site was determined to be functional-at-risk with a downward

trend. This LTA was large with only one GDE assessment available.

Therefore, there was insufficient information to evaluate composition and

condition of GDEs.

20V—Mountain Slopelands in Volcanics

	 In the Antelope Creek drainage, springs and wetlands were surveyed for

PFC assessments in 2007. These GDEs contained willow, non-willow shrub,

and herbaceous dominance groups. Water sedge (Carex aquatilis), Nebraska

sedge (Carex nebrascensis), Baltic rush (Juncus balticus), Geyer’s willow

(Salix geyeriana), shrubby cinquefoil (Potentilla fruticosa), currants (Ribes

spp.), and roses (Rosa spp.) were present. This vegetation was used as postfledging habitat by greater sage grouse. Vegetation appeared healthy where

water remained flowing during a drought cycle. Where water was absent,

dry meadow species were encroaching and willows showed dieback. Some

hummocking was noted. Five sites were determined to be functional-at-risk

and six were in properly functioning condition.

	 In the Upper Salmon basin, GDE spring surveys were conducted in the

Marco and Spud Creek watersheds in 2011. Tall deciduous tree, willow,

non-willow shrub, and herbaceous dominance groups were present. Impacts

to wetlands include channelization and downcuting, hummocking, soil

compaction, trailing, and headcutting. Shearing and soil instability occurred

at crossings or other sections of streams with livestock access. Three

wetlands were determined to be functional-at-risk and one was determined to

be in properly functioning condition.

	 In the Lemhi Basin, GDE surveys were conducted at five sites in 2015.

These GDEs contained willow, non-willow shrub, and herbaceous dominance

groups. Dominant species included Northwest Territory sedge (Carex 

utriculata), water sedge, and Booth’s willow (Salix boothii). Other plants

include tufted hair grass (Deschampsia cespitosa), mosses, and willows.

Thistles had invaded disturbed areas at one site. Impacts to GDE wetlands

included channelization soil compaction, livestock and wildlife use, trails,

trampling, lack of willow recruitment, and hummocking. Four sites were

determined to be functional-at-risk and one was in properly functioning

condition.
U.S. Forest Service RMRS GTR-394. 2019. 162

	 Three sites were visited for GDE surveys in the Big Lost River Subbasin

in 2016. Two of these sites were in properly functioning condition. These

two sites had fen-like characteristics and contained willow and herbaceousdominated communities. Sedges, rushes, and bryophytes were present. Soil

disturbance was limited to hummocking at these sites and some willow

browsing and recruitment was noted. The third site was rated as functionalat-risk because of heavy soil disturbance including compaction, erosion,

hummocks, and trails, and damage to the runout channel. Grazing and

trampling by livestock and wildlife were also noted.

	 Overall, PFC reports suggested that most GDEs had been heavily

altered with significant impacts to vegetation and soil in 20V. We therefore

determined that composition and condition were outside of the NRV.

50G—Glacial Troughlands in Granite

	 In the Antelope Creek drainage, springs and wetlands were surveyed

for PFC assessments in 2007. At one site, Douglas-fir was encroaching onto

wetland vegetation. Herbaceous dominance groups contained water sedge,

Nebraska sedge, Kentucky bluegrass (Poa pratensis), tufted hair grass, and

California false hellebore (Veratrum californicum), with Geyer’s willow

present as well. Hummocking resulted from past heavy use by cattle and elk.

Cattle had since been mostly excluded from one of the meadows. At one site,

an extensive wet meadow was lined with large willows with dieback. A large

area of exposed soil was likely being used as a mineral lick or wallow site.

All three wetland sites were determined to be functional-at-risk. This was,

however, a large LTA and there was insufficient information to evaluate the

NRV status composition and condition.

50Q—Glacial Troughlands in Quartzite

	 In the Lemhi Basin, a GDE survey was conducted in 2015. The hillslope

wetland was dominated by graminoids and bryophytes indicative of a fen

community. Bebb’s willow (Salix bebbiana) and Booth’s willow were also

present. Though no soil disturbances were noted and ground cover by hydric

vegetation was adequate, this wetland was judged to be functional-at-risk due

to lack of willow regeneration. Overall, there was insufficient information

to evaluate the NRV status of composition and condition in 50Q.

70S—Dissected Foothill Lands in Sedimentary

	 In the Antelope Creek drainage, a spring site was surveyed for a PFC

assessment in 2007. Low deciduous tree and herbaceous dominance groups

were present. These groups included gray alder (Alnus incana), Booth’s

willow, Nebraska sedge, Northwest Territory sedge, Booth’s willow, and

Baltic rush. The area was hoof-trampled by cattle and elk, old headcuts were

revegetating, and extensive wet meadow vegetation was surrounded by small,

healthy shrubs. Willow and alder saplings were observed in 2007. The site

was determined to be functional-at-risk with an upward trend. Overall, there

was insufficient information to evaluate the NRV status of composition and

condition at 70S.
U.S. Forest Service RMRS GTR-394. 2019. 163

70V—Dissected Foothill Lands in Volcanics

	 In the Antelope Creek drainage, springs and wetlands were surveyed

for PFC assessments in 2007. Willow, non-willow shrub, and herbaceous

dominance groups were present. Woody species included Geyer’s willow,

Booth’s willow, currants, roses, and shrubby cinquefoil.

	 Herbaceous dominance groups included species associated with wet

meadow and fens including water sedge, Nebraska sedge, Northwest

Territory sedge, Kentucky bluegrass, tufted hair grass, and water whorlgrass

(Catabrosa aquatica). Where water was present during this drought

cycle, wetland graminoids and riparian shrubs appeared vigorous. Where

springs had dried, willows had died back and dry meadow species had

encroached. Remnant patches of Nebraska sedge were all that was left of

wetland vegetation in these areas. Soil was exposed around ponds created

for livestock use. Channelization at one wetland may have decreased water

table and stress vegetation. Four sites were determined to be functionalat-risk, nine sites were in properly functioning condition, and one site was

nonfunctional.

	 At GDE survey sites visited in the Pahsimeroi Basin in 2014, willow,

non-willow shrub, and herbaceous dominance groups were present.

Dominant/indicator plants included willows, Ribes spp., Carex spp., Baltic

rush, tufted hair grass, and Kentucky bluegrass. Impacts included trailing

hummocking, and disturbance to wetland graminoids.

	 In the Lemhi Basin, GDE surveys were conducted at two sites in 2015.

Both sites had the potential to be fens based on water, soil, and vegetation

conditions. Herbaceous dominance groups included water sedge, Nebraska

sedge, mosses, and some willows. Of these potential fens, one was in

properly functioning condition. The other was functional-at-risk because of

impacts to inlets and channels including soil compaction, erosion, trampling

and grazing by livestock, and reduction of willow cover.

	 One site was visited for a GDE surveys in the Big Lost River Subbasin

in 2016. Aspens and upland vegetation were encroaching on willow and

herbaceous dominance groups. The site was rated as functional-at-risk

because of aspen encroachment. Grazing and browsing by livestock and

wildlife were also noted, along with hummocking in areas dominated by

sedges and other graminoids.

	 Overall, PFC reports suggested that impacts to vegetation and soil were

minor at several sites in 70V. Composition and condition were therefore

considered moderately altered.
U.S. Forest Service RMRS GTR-394. 2019. 164

VB—Valley Bottom

	 In the Lemhi Basin, a GDE survey was conducted at a site in 2015. A

narrow wetland with fen characteristics contained willow and herbaceous

dominance groups. Engelmann spruce (Picea engelmannii), Booth’s willow,

Northwest Territory sedge, water horsetail (Equisetum fluviatile), graminoids,

mosses, and forbs were present. This narrow peatland had been affected by

willow browsing and trailing by livestock and wildlife. This was a large LTA

without additional assessments, so there was insufficient information to

evaluate the composition and condition of GDEs.
U.S. Forest Service RMRS GTR-394. 2019. 165

Appendix I—Maps

Stressor Maps

Figure I1—Percentage of land within each LTA affected by timber harvest. The data were derived from the USFS Terrestrial 

Condition Assessment (Cleland et al. 2017).
U.S. Forest Service RMRS GTR-394. 2019. 166

Figure I2—Diversions per acre within each LTA. The data were derived from the Salmon-Challis National Forest diversions 

layer. 
U.S. Forest Service RMRS GTR-394. 2019. 167

Figure I3—Percentage of floodplain impacted by vegetation mortality by LTA. The data were derived from the USFS Terrestrial 

Condition Assessment roads layer and the 50-year floodplain map (Abood et al. 2012).
U.S. Forest Service RMRS GTR-394. 2019. 168

Figure I4—Road miles per floodplain acre by LTA. The data were derived from the USFS Terrestrial Condition Assessment 

roads layer and the 50-year floodplain map (Abood et al. 2012).
U.S. Forest Service RMRS GTR-394. 2019. 169

Figure I5—Percentage of floodplains converted into recreation sites by LTA. The data were derived from the Salmon-Challis 

National Forest recreation site layer and the 50-year floodplain map (Abood et al. 2012).
U.S. Forest Service RMRS GTR-394. 2019. 170

Figure I6—Percent of LTA located within an active grazing allotment. The data were derived from the Salmon-Challis National 

Forest allotment layer. 
U.S. Forest Service RMRS GTR-394. 2019. 171

Figure I7—Percentage of vegetation within the LTA that is impacted by mortality and defoliation. The data were derived from 

the USFS Terrestrial Condition Assessment (Cleland et al. 2017).
U.S. Forest Service RMRS GTR-394. 2019. 172

Figure I8—Road miles per acre within the LTA. The data were derived from the USFS Terrestrial Condition Assessment roads 

layer (Cleland et al. 2017). 
U.S. Forest Service RMRS GTR-394. 2019. 173

Figure I9—Mines per acre within the LTA. The data were derived from the Salmon-Challis National Forest layer. 
U.S. Forest Service RMRS GTR-394. 2019. 174

Figure I10—Percentage deviation in winter precipitation from 2010 to 2014 compared to previous century by LTA. The data 

were derived from the USFS Terrestrial Condition Assessment (Cleland et al. 2017).

Indicator Maps
U.S. Forest Service RMRS GTR-394. 2019. 175

Figure I11—Deviation in winter temperature (°F) from 2010 to 2015 compared to previous century by LTA. The data were 

derived from the USFS Terrestrial Condition Assessment (Cleland et al. 2017).
U.S. Forest Service RMRS GTR-394. 2019. 176

Figure I12—Average Community Tolerance Quotient of macroinvertebrates by LTA. The data were derived from the PIBO 

effectiveness monitoring program and include 501 samples collected on the Salmon-Challis National Forest between 2001 

and 2016.
U.S. Forest Service RMRS GTR-394. 2019. 177

Figure I13—Floodplain acre per stream mile by LTA. The data were derived based on the NHD flowline layer and the 50-year 

floodplain map (Abood et a. 2012).
U.S. Forest Service RMRS GTR-394. 2019. 178

Figure I14—Volume of large woody debris (m3/km) within the stream channel by LTA. The data were derived from the PIBO 

effectiveness monitoring program and include 501 samples collected on the Salmon-Challis National Forest between 2001 

and 2016.
U.S. Forest Service RMRS GTR-394. 2019. 179

Figure I15—Frequency of large woody debris (pieces/km) within the stream channel by LTA. The data were derived from the 

PIBO effectiveness monitoring program and include 501 samples collected on the Salmon-Challis National Forest between 

2001 and 2016.
U.S. Forest Service RMRS GTR-394. 2019. 180

Figure I16—Average streambank angle by LTA. The data were derived from the PIBO effectiveness monitoring program and 

include 501 samples collected on the Salmon-Challis National Forest between 2001 and 2016.
U.S. Forest Service RMRS GTR-394. 2019. 181

Figure I17—Average streambank stability by LTA. The data were derived from the PIBO effectiveness monitoring program and 

include 501 samples collected on the Salmon-Challis National Forest between 2001 and 2016.
U.S. Forest Service RMRS GTR-394. 2019. 182

Figure I18—Average stream channel sinuosity by LTA. The data were derived from the PIBO effectiveness monitoring 

program and include 501 samples collected on the Salmon-Challis National Forest between 2001 and 2016.
U.S. Forest Service RMRS GTR-394. 2019. 183

Figure I19—Average PIBO index by LTA. The PIBO index is a numeric score 0 (worst) to 100 (best) that ranks habitat integrity 

of a reach by considering six metrics (residual pool depth, percent pools, median substrate size, percent pool tail fines <6 mm, 

large wood frequency, and average bank angle). The data were derived from the PIBO effectiveness monitoring program and 

include 501 samples collected on the SCNF between 2001 and 2016.
U.S. Forest Service RMRS GTR-394. 2019. 184

Figure I20—Percentage of perennial stream miles affected by upland encroachment by LTA. The data were derived from the 

riparian vegetation conversion type classification tool of the R-CAT suite.
U.S. Forest Service RMRS GTR-394. 2019. 185

Figure I21—Percentage of perennial stream miles affected by conifer encroachment by LTA. The data were derived from the 

riparian vegetation conversion type classification tool of the R-CAT suite.
U.S. Forest Service RMRS GTR-394. 2019. 186

Figure I22—Percentage of intermittent stream miles affected by upland encroachment by LTA. The data were derived from the 

riparian vegetation conversion type classification tool of the R-CAT suite.
U.S. Forest Service RMRS GTR-394. 2019. 187

Figure I23—Percentage of intermittent stream miles affected by conifer encroachment by LTA. The data were derived from the 

riparian vegetation conversion type classification tool of the R-CAT suite.
U.S. Forest Service RMRS GTR-394. 2019. 188

Figure I24—Median summer stream temperature by LTA. The data were derived from the PIBO effectiveness monitoring 

program and include 293 samples collected on the Salmon-Challis National Forest between 2000 and 2016. 
U.S. Forest Service RMRS GTR-394. 2019. 189

Figure I25—Median substrate size (m) by LTA. The data were derived from the PIBO effectiveness monitoring program and 

include 501 sample sets collected on the Salmon-Challis National Forest between 2001 and 2016.
U.S. Forest Service RMRS GTR-394. 2019. 190

Appendix J—Acronyms

AZAR 	 Aquatic Zone Analysis Rating

BLM 	 Bureau of Land Management

BMP	 Best Management Practices

BPS	 Biophysical Setting

CTQ 	 Community Tolerance Quotient

EVT	 Existing Vegetation Type

GDE 	 Groundwater-Dependent Ecosystems

HGVC 	 Hydrogeomorphic Valley Classification

IDEQ 	 Idaho Department of Environmental Quality

KEC	 Key Ecosystem Characteristic

LTA 	 Land Type Association

D50	 Median Substrate Size

MIM 	 Multiple Indicator Monitoring

NHD 	 National Hydrography Dataset

NRV 	 Natural Range of Variation	

NWI 	 National Wetlands Inventory

PEMB	 Palustrine Emergent Wetlands

PFC 	 Proper Functioning Condition

PIBO 	 Pacfish-Infish Biological Opinion

R-CAT 	 Riparian Condition Assessment Tool

RVD	 Riparian Vegetation Departure

SCNF 	 Salmon-Challis National Forest

USFS 	 United States Forest Service

USGS 	 United States Geological Survey

VCA	 Valley Confinement Algorithm

WCF	 Watershed Condition Framework
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