Natural Resources
Conservation Service
Ecological site R035XY013UT
Semiwet Fresh Streambank (Fremont Cottonwood)
Accessed: 04/28/2026
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Draft. A draft ecological site description is either incomplete or has not undergone quality control and quality assurance review.
Associated sites
R035XY010UT Semiwet Fresh Meadow
R035XY015UT Sandy Bottom
R035XY212UT Semidesert Sand (Fourwing Saltbush)
Similar sites
R035XY012UT Semiwet Saline Streambank (Fremont Cottonwood)
R034BY011UT River Flood Plain (Fremont Cottonwood)
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Salix exigua
(2) Salix luteaHerbaceous Not specified
Physiographic features
This site occurs on flood plains, terraces, and stream terraces. Run off is negligible to low due to the low slope (0-6%) and the high permeability of the soil. The elevation ranges from 3840ft to 5800.
Table 2. Representative physiographic features
Landforms (1) Stream terrace
(2) Flood plain
(3) Terrace
Flooding duration Very brief (4 to 48 hours) to brief (2 to 7 days) Flooding frequency None to occasional Ponding frequency None to rare Elevation 3840 – 5800 ft Slope 0 – 6 % Water table depth 20 – 39 in Aspect Aspect is not a significant factor Climatic features
The climate is characterized by hot summers and cool to warm winters, which can be slightly modified by local topographic conditions, such as aspect. Large fluctuations in daily temperatures are common. Mean annual high temperatures range from 52-59 degrees Fahrenheit and mean annual low temperatures range from 45-53 degrees Fahrenheit. Precipitation is variable from month to month and from year to year but averages between 5-12 inches. Approximately 70% occurs as rain from March through October. On the average, April, May, and June are the driest months and July through October are the wettest months. Much of the summer precipitation occurs as convection thunderstorms.
Table 3 Representative climatic features
Frost-free period (average) 200 days Freeze-free period (average) 200 days Precipitation total (average) 10 in BarLineFigure 1. Monthly precipitation range
BarLineFigure 2. Monthly average minimum and maximum temperature
">Influencing water features
Soil features
The soils are very deep and moderately well to excessively well drained. Typically the dry surface is brown to reddish brown. Typically soil surface fragments are 0%. The soil temperature and moisture regimes are mesic and aridic (torric) respectively. Surface and subsurface textures are generally loamy fine sandy loams and very fine sandy loams. Soils are nonsaline to very slight saline.
This site has been used in the following soil surveys and has been correlated to the following components:
UT686 – Escalante Grand Staircase National Monument – Bowington; Radnik
UT687 – Arches National Park – Fernley Family
UT688 – Canyonlands National Park – Green River; Green River Family; Radnik
Typical Profile:
A – 0-11 inches; loam; moderately alkaline
C – 12-60+ inches; fine sand to loamy fine sand; moderately alkaline
Table 4. Representative soil features
Surface texture (1) Fine sand
(2) Silt loam
(3) Very fine sand
Family particle size (1) Sandy
Drainage class Moderately well drained to excessively drained Permeability class Rapid to very rapid Soil depth 50 – 60 in Surface fragment cover <=3" Not specified Surface fragment cover >3" Not specified Available water capacity
(0-40in)1.6 – 3.1 in Calcium carbonate equivalent
(0-40in)1 – 10 % Electrical conductivity
(0-40in)0 – 2 mmhos/cm Sodium adsorption ratio
(0-40in)Not specified Soil reaction (1:1 water)
(0-40in)6.6 – 8.4 Subsurface fragment volume <=3"
(Depth not specified)0 – 3 % Subsurface fragment volume >3"
(Depth not specified)Not specified Ecological dynamics
(includes a discussion of seral stages; fire influence and effects; effects of prolonged wet or dry periods; resistance to change; the influence of such things as grazing, rodent concentrations, insects, diseases, introduced species, and soil erosion or deposition; other stable vegetative states associated with this site as a result of extreme disturbance)
This site provides erosion control by regulating sediment transport and distribution, enhance water quality, produce organic matter for aquatic habitats, and provide wildlife habitat. Due to the high human recreation use of this area, cattle use has become controversial. High moisture over most of the year makes the site resistant to change and resilient after change.
The suitability for rangeland seeding is good. The major limiting factors are extended high water and flooding at critical times of the year. Streambank can be susceptible to erosion by high water levels during flash floods and overgrazing by cattle can cause step sloughing.
A wide variety of seral stages and site development can be found with the dynamic river system. When newly deposited sediments become stabilized, early stages of primary plant succession appear and begin to advance toward the potential plant community. Natural meandering of the river also cuts away established parts of the community. This natural process within a river floodplain ecosystem makes it very difficult to determine the potential natural plant community.
The most likely invaders are salt cedar and Russian olive which can increase in number until they have choked out the native vegetation. Salt cedar can form dense stands in this site.
State and transition model
More interactive model formats are also available. View Interactive Models
Click on state and transition labels to scroll to the respective textEcosystem states
State 1 submodel, plant communities
State 1
Reference StateCommunity 1.1
Reference StateThe dominant aspect of the plant community is an overstory of Fremont cottonwood with shrubs (willow and basin big sagebrush) and grasses (streamside wildrye and western wheatgrass) in understory. The composition by air-dry weight is approximately 40% perennial grasses, 5% forbs, 50% shrubs, and 5% trees. In average years, plants begin growth around March 1 and end growth around October 15.
Figure 3. Annual production by plant type (representative values) or group (midpoint values)
Table 5. Annual production by plant type
Plant type Low
(lb/acre)Representative value
(lb/acre)High
(lb/acre)Shrub/Vine 600 675 775 Grass/Grasslike 480 540 620 Tree 60 68 78 Forb 60 68 78 Total 1200 1351 1551 Table 6. Ground cover
Tree foliar cover 10-20% Shrub/vine/liana foliar cover 20-20% Grass/grasslike foliar cover 40-40% Forb foliar cover 0-10% Non-vascular plants 0% Biological crusts 0% Litter 0% Surface fragments >0.25" and <=3" 0% Surface fragments >3" 0% Bedrock 0% Water 0% Bare ground 0% Table 7. Canopy structure (% cover)
Height Above Ground (ft) Tree Shrub/Vine Grass/
GrasslikeForb <0.5 – – – – >0.5 <= 1 – – – 4-6% >1 <= 2 – – 39-41% – >2 <= 4.5 – 19-21% – – >4.5 <= 13 – – – – >13 <= 40 14-16% – – – >40 <= 80 – – – – >80 <= 120 – – – – >120 – – – – Additional community tables
Table 8. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Tree0 Dominant Trees 39–70 Grass, annual 2GA Grass, annual 39–70 – Grass, perennial 2GP Grass, perennial 39–70 – saltgrass DISP Distichlis spicata 13–42 – slender wheatgrass ELTR7 Elymus trachycaulus 13–42 – Sandberg bluegrass POSE Poa secunda 13–42 – Shrub/Vine0 Dominant Shrubs 364–630 Forb, annual 2FA Forb, annual 65–140 – Forb, perennial 2FP Forb, perennial 65–140 – Fremont's goosefoot CHFR3 Chenopodium fremontii 13–42 – Rocky Mountain beeplant CLSE Cleome serrulata 13–42 – western tansymustard DEPII Descurainia pinnata ssp. intermedia 13–42 – curlycup gumweed GRSQ Grindelia squarrosa 13–42 – 3 Sub Dominant Shrubs 78–196 Grass/Grasslike0 Dominant Grasses 312–560 Shrub (>.5m) 2SHRUB Shrub (>.5m) 39–70 – yellow rabbitbrush CHVI8 Chrysothamnus viscidiflorus 13–42 – skunkbush sumac RHTRT Rhus trilobata var. trilobata 13–42 – greasewood SAVE4 Sarcobatus vermiculatus 13–42 – 1 Sub-Dominant Grasses 130–308 Forb0 Dominant Forbs 39–70 2 Sub-Dominant Forbs 182–448 Interpretations
Animal community
This site provides proper grazing for cattle and sheep during all seasons of the year.
This site provides food and cover for wildlife. Shade and water may concentrate
use by cattle and recreationists.
Nesting sites and habitat for birds, deer, rabbits, chipmunks, coyote, bobcats, mountain lions, jackrabbits, kangaroo rat, snake, mule deer, hawks, owls, and ravens.
Recreational uses
Recreational values are camping, hiking, aesthetics and hunting.
Wood products
Firewood
Supporting information
Contributors
SM, TS, SN
Rangeland health reference sheet
Interpreting Indicators of Rangeland Health is a qualitative assessment protocol used to determine ecosystem condition based on benchmark characteristics described in the Reference Sheet. A suite of 17 (or more) indicators are typically considered in an assessment. The ecological site(s) representative of an assessment location must be known prior to applying the protocol and must be verified based on soils and climate. Current plant community cannot be used to identify the ecological site.
Author(s)/participant(s) Contact for lead author Date Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
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Number and extent of rills:
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Presence of water flow patterns:
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Number and height of erosional pedestals or terracettes:
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Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
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Number of gullies and erosion associated with gullies:
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Extent of wind scoured, blowouts and/or depositional areas:
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Amount of litter movement (describe size and distance expected to travel):
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Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
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Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
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Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
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Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
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Functional/Structural Groups (list in order of descending dominance by above-ground annual-production or live foliar cover using symbols: >>, >, = to indicate much greater than, greater than, and equal to):
Dominant:
Sub-dominant:
Other:
Additional:
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Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
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Average percent litter cover (%) and depth ( in):
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Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
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Potential invasive (including noxious) species (native and non-native). List species which BOTH characterize degraded states and have the potential to become a dominant or co-dominant species on the ecological site if their future establishment and growth is not actively controlled by management interventions. Species that become dominant for only one to several years (e.g., short-term response to drought or wildfire) are not invasive plants. Note that unlike other indicators, we are describing what is NOT expected in the reference state for the ecological site:
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Perennial plant reproductive capability:
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