Natural Resources
Conservation Service
Ecological site F035XC332AZ
Sandy Bottom
10-14"
(PODEW, SAEX), Perennial (Provisional)
Accessed: 04/24/2026
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Provisional. A provisional ecological site description has undergone quality control and quality assurance review. It contains a working state and transition model and enough information to identify the ecological site.
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Figure 1. Mapped extent
Areas shown in blue indicate the maximum mapped extent of this ecological site. Other ecological sites likely occur within the highlighted areas. It is also possible for this ecological site to occur outside of highlighted areas if detailed soil survey has not been completed or recently updated.
MLRA notes
Major Land Resource Area (MLRA): 035X–Colorado Plateau
Land Resource Unit 35.3 – Colorado Plateau Sagebrush – Grasslands
This Land Resource Unit occurs within the Colorado Plateau Physiographic Province and is characterized by a sequence of flat to gently dipping sedimentary rocks eroded into plateaus, valleys and deep canyons. Elevations for the Common Resource Area where this ecological site may occur range from 4800 to 6700 feet and precipitation averages 10 to 14 inches. The elevation range is lower (about 4500 to 6000 ) on the western edge of the Colorado Plateau along the Grand Canyon, and moves up about 500 to 800 feet higher on the eastern side in the areas of the Navajo and Hopi Indian Reservations due to rain shadow effects from the Kaibab Plateau and Mogollon Rim. Common vegetation in this region includes Wyoming big sagebrush, Utah juniper, Colorado pinyon - cliffrose, Mormon tea, fourwing saltbush, blackbrush Indian ricegrass, needle and thread, western wheatgrass Galleta, black grama, blue grama, and sand dropseed. Sedimentary rock classes dominate the plateau with volcanic fields occurring for the most part near its margin. The soil temperature regime is mesic and the soil moisture regime is ustic aridic.Ecological site concept
“ATTENTION: This ecological site meets the requirements for PROVISIONAL (if not more). A provisional ecological site is established after ecological site concepts are developed and an initial state-and-transition model is drafted. A provisional ecological site typically will include literature reviews, land use history information, legacy data (prior approved range site descriptions, forage suitability groups, woodland suitability groups, etc.,), and includes some soils data, and estimates for canopy and/or species composition by weight,. A provisional ecological site provides the conceptual framework of soil-site correlation for the development of the ESD. For more information about this ecological site, please contact your local NRCS office.”
Associated sites
R035XC302AZ Sedimentary Cliffs 10-14" p.z.
This site is located on cliff faces and talus slopes above the referenced site.
R035XC317AZ Sandy Loam Upland 10-14" p.z.
This site is located on non-flooded uplands that may be found adjacent to this ecological site.
Similar sites
F035XF637AZ Loamy Bottom 13-17" p.z.
This site has similar dominant vegetation as the referenced site, but is found in common resource area 35-6 with higher precipitation, cooler temparatures and shorter growing seasons. It may be located upstream from the referenced site.
Table 1. Dominant plant species
Tree (1) Populus deltoides ssp. wislizeni
Shrub (1) Salix exigua
Herbaceous Not specified
Physiographic features
This site occurs on floodplains and low floodplain terraces of perennial or intermittent streams with perennial or seasonal subsurface flows. The site receives additional moisture from occasional, very brief periods of flooding. Depth to a seasonal high water table is 0 inches to 48 inches that also benefits the site.
Table 2. Representative physiographic features
Landforms (1) Flood plain
(2) Stream terrace
Flooding duration Very brief (4 to 48 hours) to brief (2 to 7 days) Flooding frequency Occasional to frequent Ponding frequency None Elevation 4800 – 6700 ft Slope 0 – 5 % Water table depth 10 – 60 in Aspect Aspect is not a significant factor Climatic features
The soil temperature regime is mesic and the soil moisture regime is typic aridic. Annual precipitation usually ranges from 10 to 14 inches per year. Approximately 60 percent of the rainfall comes from October through May as gentle rain and snow from Pacific storms which may last for a couple of days. The rest of the rainfall comes during the summer monsoon season from June through September as spotty, brief, intense thunderstorms. The mean annual air temperature ranges from 50 to 55 degrees F.
Cool season plants start growth in mid-spring and mature in early summer. Warm season plants start growth in mid-summer and stay green until the late fall to take advantage of summer rains.Table 3 Representative climatic features
Frost-free period (average) 180 days Freeze-free period (average) 210 days Precipitation total (average) 10 in BarLineFigure 2. Monthly precipitation range
BarLineFigure 3. Monthly average minimum and maximum temperature
">Influencing water features
The natural stream type for this site was most likely a Rosgen type “E” channel. Historic photographic evidence shows that the streams within this site were Rosgen type “D” channels at the turn of this century. That is they have slopes less than 4%, were braided with high bedloads and bank erosion. Stream channels are wide and relatively shallow.
Soil features
The soils are very deep and moderately well drained. They are formed in alluvium derived from sandstone, granite and quartzite. Surface textures normally range from sandy loam to very fine sandy loam, but can include coarser textures. Subsurface textures include loam, fine sandy loam, and loamy sand. Stratified layers below 40 inches may have greater then 35% rock fragments and more than 15% clay. Hazard of water erosion is moderate to high and hazard of wind erosion is moderate to high. Soil surface rock fragments are uncommon unless the surface has eroded to a coarse alluvial layer. Rock fragments are more common on surface of active stream channel.
This ecological site has been correlated to the following soil map unit components:
Canyon de Chelly (AZ712) Soil Map Unit Components 5-Bebeevar
Fort Defiance Area (AZ715) Soil Map Unit Components 97-Bebeevar
Table 4. Representative soil features
Parent material (1) Alluvium – sandstone
Surface texture (1) Loamy coarse sand
(2) Sand
(3) Fine sandy loam
Family particle size (1) Sandy
Drainage class Moderately well drained Permeability class Moderately rapid Soil depth 60 – 80 in Surface fragment cover <=3" 0 – 20 % Surface fragment cover >3" 0 – 10 % Available water capacity
(0-40in)8.2 in Calcium carbonate equivalent
(0-40in)1 – 5 % Sodium adsorption ratio
(0-40in)0 – 5 Soil reaction (1:1 water)
(0-40in)7.4 – 8.1 Subsurface fragment volume <=3"
(Depth not specified)0 – 20 % Subsurface fragment volume >3"
(Depth not specified)0 – 10 % Ecological dynamics
An ecological site is not a precise assemblage of species for which the proportions are the same from place to place or from year to year. In all plant communities, variability is apparent in productivity and occurrence of individual species. Spatial boundaries of the communities; however, can be recognized by characteristic patterns of species composition, association, and community structure. The historic climax plant community for this ecological site has been estimated by sampling relict or relatively undisturbed sites and/or reviewing historic records. The historic climax plant community is the plant community that evolved over time with the soil forming process and long term changes in climatic conditions of the area. It is the plant community that was best adapted to the unique combination of environmental factors associated with the site.
Natural disturbances, such as drought, fire, grazing of native fauna, and insects, are inherent in the development and maintenance of these plant communities. The effects of these disturbances are part of the range of characteristics of the ecological site. Fluctuations in plant community structure and function caused by the effects of natural disturbances help establish the boundaries and characteristics of an ecological site. They are accounted for as part of the range of characteristics of the ecological site. Recognizable plant community phases are identified in the reference state of the ecological site. Some sites may have a small range of variation, while others have a large range. Some plant community phases may exist for long periods of time, while others may only occur for a couple of years after a disturbance.
If there is significant loss of soil surface through erosion, if there a loss of the soil stability on the site due to active erosion on the site, if the hydrology of the site is significantly modified by increasing runoff amounts and/or patterns, if there are changes in availability of surface and subsurface water, or if the biotic integrity of the site is altered though changes in plant structural and functional types or the introduction of non-native species, then potential of the ecological site to return to the historic climax plant community can be lost, or restoration would require significant inputs . The site deterioration results in the crossing of a threshold or irreversible boundary to another state, or equilibrium, for the ecological site. There may be multiple states possible for an ecological site, determined by the type and or severity of disturbance.
The known states and transition pathways for this ecological site are described in the state and transition model. Within each state, there may be one or more known plant community phases. These community phases describe the different plant community that can be recognized and mapped on this ecological site. The state and transition model is intended to help land users determine the current plant community phase on the ecological site, and the management options for improving the plant community to the desired plant community.State and transition model
Custom diagramStandard diagram
Figure 4. 353 Sandyloam Bottom Forest S&T
More interactive model formats are also available. View Interactive Models
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 2 submodel, plant communities
State 3 submodel, plant communities
State 1
Reference StateCommunity 1.1
Historic Climax Plant Community
Figure 5. Sandy Loam Bottom
The Historic Climax Plant Community (HCPC) is dominated by a canopy of Rio Grande cottonwood (Populus deltoides ssp. wislizenii, with lesser amounts of red willow (Salix laevigata) and other native willows. The understory is a mix of shrubs such as redosier dogwood (Cornus sericea) and chokecherry (Prunus spp.) with cool-season and warm season grasses and forbs. Overstory canopy cover can come close to 90 percent, but will fluctuate with flood events under natural conditions. These fluctuations allow gaps in the canopy that are important for the recruitment of young cottonwoods and willows into the overstory.
Figure 6. 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 150 250 500 Tree 200 300 400 Grass/Grasslike 50 110 150 Forb 5 10 30 Total 405 670 1080 Table 6. Ground cover
Tree foliar cover 10-80% Shrub/vine/liana foliar cover 0-10% Grass/grasslike foliar cover 0-10% Forb foliar cover 0-10% Non-vascular plants 0% Biological crusts 0% Litter 0-30% Surface fragments >0.25" and <=3" 0-0% Surface fragments >3" 0% Bedrock 0% Water 0% Bare ground 10-20% Table 7. Soil surface cover
Tree basal cover 0-0% Shrub/vine/liana basal cover 0-0% Grass/grasslike basal cover 0-0% Forb basal cover 0-0% Non-vascular plants 0-0% Biological crusts 0% Litter 40-60% Surface fragments >0.25" and <=3" 0-0% Surface fragments >3" 0% Bedrock 0% Water 0% Bare ground 40-70% Figure 7. Plant community growth curve (percent production by month). AZ3531 , 35.3 10-14" p.z. all sites. Growth begins in the spring and continues through the summer..
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec J F M A M J J A S O N D 0 1 3 17 18 10 19 20 10 1 1 0 Community 1.2
Riparian Shrub / Tree CommunityThe overstory is dominated by coyote willow. There may be some mature and decadent cottonwood and other willows in the community, but they do not dominate the overstory. There is an understory of cottonwood, and other shrubs. There are scattered cool-season and warm season grasses and forbs in the understory.
Pathway 1.2A
Community 1.2 to 1.1Natural regrowth of native trees such as cottonwood and willow.
Conservation practices
Prescribed Grazing State 2
Natives with Introduced Annuals StateCommunity 2.1
Riparian Forest with Non-Native HerbaceousThe overstory consists primarily of cottonwood and some willow species. The herbaceous understory consists of a mix of the native herbaceous species with non-native grasses, including ripgut brome (Bromus diandrus), cheatgrass (Bromus tectorum) and Kentucky bluegrass (Poa pratensis).
State 3
Native and Introduced Tree/Shrub StateCommunity 3.1
Native / Non-Native Tree Shrub CommunityThe overstory consists of a mix of cottonwood and some willow species, with non-native trees including Russian olive and/or saltcedcar. There are few understory plants but they include a mix of native and non native perennial and annual grasses and forbs. Non native grasses include ripgut brome, cheatgrass and Kentucky bluegrass.
Community 3.2
Non-Native Riparian Tree CommunityThis is a riparian plant community dominated by non-native trees such as salt cedar and/or Russian olive. The understory includes a mix of native and non-native shrubs and herbaceous species.
Pathway 3.1A
Community 3.1 to 3.2Loss of native trees from flooding, fire, or drought.
Pathway 3.2A
Community 3.2 to 3.1Control of non-native trees and shrubs, and planting of native trees. Grazing by livestock and wildlife must be managed.
Conservation practices
Forest Stand Improvement Prescribed Grazing Transition T1A
State 1 to 2Introduction of non-native herbaceous species into the plant community.
Transition T2A
State 1 to 3Introduction of non-native trees into the plant community.
Transition T2A
State 2 to 3Introduction of non-native trees into the plant community.
Transition T2A
State 2 to 3Introduction of non-native trees into the plant community.
Restoration pathway R2A
State 3 to 2Control of non-native trees and planting of native trees. Grazing by livestock and wildlife must be properly managed.
Conservation practices
Brush Management Riparian Forest Buffer Prescribed Grazing Additional community tables
Table 8. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 Perennial Cool Season Rizomatous Grass 20–100 slender wheatgrass ELTRT Elymus trachycaulus ssp. trachycaulus 20–100 – mountain rush JUARL Juncus arcticus ssp. littoralis 1–20 – Mexican rush JUME4 Juncus mexicanus 1–20 – 2 Perennial Bunchgrass 5–30 sand dropseed SPCR Sporobolus cryptandrus 5–20 – foxtail barley HOJU Hordeum jubatum 1–5 – 3 Perennial Warm Season Rhizomatous Grass 1–10 scratchgrass MUAS Muhlenbergia asperifolia 1–10 – 4 Annual Grasses 1–5 sixweeks grama BOBA2 Bouteloua barbata 1–5 – mouse barley HOMU Hordeum murinum 1–5 – sixweeks fescue VUOC Vulpia octoflora 1–5 – Forb5 Perennial Forbs 1–5 common yarrow ACMI2 Achillea millefolium 1–5 – milkvetch ASTRA Astragalus 1–5 – thistle CIRSI Cirsium 1–5 – horsetail EQUIS Equisetum 1–5 – fleabane ERIGE2 Erigeron 1–5 – ragwort SENEC Senecio 1–5 – water speedwell VEAN2 Veronica anagallis-aquatica 1–5 – 6 Annual Forbs 1–5 flatspine bur ragweed AMAC2 Ambrosia acanthicarpa 1–5 – sandmat CHAMA15 Chamaesyce 1–5 – Rocky Mountain beeplant CLSE Cleome serrulata 1–5 – American bugseed COAMA2 Corispermum americanum var. americanum 1–5 – Canadian horseweed COCA5 Conyza canadensis 1–5 – Texas croton CRTE4 Croton texensis 1–5 – western tansymustard DEPI Descurainia pinnata 1–5 – wedgeleaf draba DRCUC Draba cuneifolia var. cuneifolia 1–5 – kiss me quick POPI3 Portulaca pilosa 1–5 – globemallow SPHAE Sphaeralcea 1–5 – dandelion TARAX Taraxacum 1–5 – golden crownbeard VEENE2 Verbesina encelioides ssp. exauriculata 1–5 – Shrub/Vine7 Young Coyote Willow 100–400 narrowleaf willow SAEX Salix exigua 100–400 – 8 Other tall Shrub 20–50 redosier dogwood COSES Cornus sericea ssp. sericea 5–25 – chokecherry PRVI Prunus virginiana 5–25 – Woods' rose ROWO Rosa woodsii 5–15 – 9 Halfshrub 5–25 hairy false goldenaster HEVI4 Heterotheca villosa 5–25 – white sagebrush ARLU Artemisia ludoviciana 1–5 – Tree10 Cottonwood, Tall Willow 200–400 Rio Grande cottonwood PODEW Populus deltoides ssp. wislizeni 100–200 – narrowleaf willow SAEX Salix exigua 100–200 – red willow SALA3 Salix laevigata 100–200 – arroyo willow SALA6 Salix lasiolepis 50–100 – Goodding's willow SAGO Salix gooddingii 50–100 – peachleaf willow SAAM2 Salix amygdaloides 50–100 – pricklypear OPUNT Opuntia 0–50 – Table 9. Community 1.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 10. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 11. Community 3.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Table 12. Community 3.2 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
This site is suitable for grazing by livestock and wildlife during most of the grazing periods except when snow cover restricts availability of forage. Grazing must be managed to allow for periodic reproduction of cottonwood and willow species. Seeds germinate in beds of alluvium left after spring or summer floods. Spring seedlings require one full season to grow out of reach of grazing stock. Summer seedlings may require two seasons to reach a height where the terminal bud is out of reach. Seedlings of both species are very palatable to cattle.
This wetland site attracts many species of upland and wetland wildlife Which use this site for nesting, feeding and resting. Competition with livestock can be year-round.
The "Plant Preference By Animal Kind" Table Information below was compiled from information from similar riparian sites in Arizona and a summary table compiled for all sites in MLRA 35 in Utah.Hydrological functions
This site is very important in the hydrology of southwestern stream systems. Large amounts of coarse woody debris form dams in large floods and spread waters over the floodplain. Beavers helped maintain a mosaic of marshy areas. Dense vegetation shade floodplains and stream channels to reduce evaporation. Vegetation traps sediment improving water quality and building floodplains.
Recreational uses
The cottonwood trees, understory shrubs and grasses, and perennial or intermittent stream beds provide an aesthetically pleasing site on the low floodplains.
The winters are cold and the springs tend to be dry and windy. Late spring, summer and fall are the most pleasant seasons for outdoor activities such as bird watching, wildlife observation, hunting, and camping.Wood products
Wood cutting should be limited to flood-damaged and fallen trees and driftwood.
Table 13. Representative site productivity
Common name Symbol Site index low Site index high CMAI low CMAI high Age of CMAI Site index curve code Site index curve basis Citation Rio Grande cottonwood PODEW 130 150 75 100 – – – Supporting information
Type locality
Location 1: Apache County, AZ UTM zone N UTM northing 4001219 UTM easting 631747 General legal description The typical site is located within Canyon de Chelly National Monument, on Navajo tribal lands. It is located just west of "The Window" a natural arch that is approximately 2.75 miles west of Spider Rock in Canyon de Chelly canyon. Contributors
Kevin Williams
Larry D. Ellicott
Steve BarkerRangeland 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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