Natural Resources
Conservation Service
Ecological site R030XB218AZ
Sandy Wash
6-9" p.z.
Last updated: 10/21/2024
Accessed: 04/19/2026
-
Search
Major Land Resource Area or ecological site by name and/or ID.
PreviousSectionsNextGeneral information
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.
Click to explore map
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): 030X–Mojave Basin and Range
This unit occurs within the Basin and Range Province and is characterized by broad basins, valleys, and old lakebeds. Widely spaced mountains trending north to south occur throughout the area. Isolated, short mountain ranges are separated by an aggraded desert plain. The mountains are fault blocks that have been tilted up. Long alluvial fans coalesce with dry lakebeds between some of the ranges.
LRU notes
AZ LRU 30-2 – Middle Mohave Desert
Elevations range from 1500 to 3200 feet and precipitation averages 6 to 9 inches per year. Vegetation includes creosotebush, white bursage, yucca, prickly pear and cholla species, Mormon tea, flattop buckwheat, ratany, winterfat, bush muhly, threeawns, and big galleta. The soil temperature regime is thermic and the soil moisture regime is typic aridic.Ecological site concept
This ecological site is located in bottoms. Soils are gravelly sandy loams braided with watercourses of riverwash.
Table 1. Dominant plant species
Tree Not specified
Shrub (1) Hymenoclea salsola
(2) Larrea tridentataHerbaceous (1) Pleuraphis rigida
Physiographic features
This ecological site occurs in and along the edges of ephemeral streams or washes. It is often intricately intertwined with, but is not, the riverwash. It occasionially receives additional run-in moisture from the surrounding ecological sites. The soil is very sandy and is often gravelly and/or cobbly as well.
Table 2. Representative physiographic features
Landforms (1) Alluvial fan
(2) Flood plain
Flooding duration Very brief (4 to 48 hours) Flooding frequency Occasional Ponding frequency None Elevation 1500 – 3000 ft Slope 1 – 5 % Aspect Aspect is not a significant factor Climatic features
The climate is arid and warm. Annual precipitation ranges from 6 to 9 inches. About 65 percent of the rainfall comes from October through May as gentle rain from Pacific storms which may last for a couple of days. The rest of the rainfall comes during the summer monsoon season from July through September as spotty, brief, intense thunderstorms. Snow rarely falls, and only remains on the ground a few hours at most. Annual air temperature ranges from 59 to 70 degrees F. The average frost-free period ranges from 156 to 259 days.
Table 3 Representative climatic features
Frost-free period (average) 260 days Freeze-free period (average) 290 days Precipitation total (average) 10 in BarLineFigure 2. Monthly precipitation range
BarLineFigure 3. Monthly average minimum and maximum temperature
">Influencing water features
Soil features
The soil of this ecological site is deep to very deep. Surface textures range from loamy sand to sandy loam and is often gravelly or very gravelly. Subsurface textures range from sand to sandy loam and generally gravelly to extremely gravelly or very cobbly.
A typical profile of this soil is:
A—0 to 1 inch; gravelly sandy loam
C1—1 to 9 inches; loamy coarse sand
C2—9 to 60 inches; extremely gravelly loamy
coarse sand
The taxonomic classification of this soil is Sandy, mixed thermic Typic Torrifluvents.
Soils correlated to this ecological site include map unit 623005, Arizo, Shivwits SSA; 697006, Arizo and Franconia, 697007, Arizo, Central Mohave County SSA.
Table 4. Representative soil features
Surface texture (1) Gravelly sandy loam
(2) Very cobbly sandy loam
(3) Very gravelly loamy sand
Family particle size (1) Sandy
Drainage class Excessively drained Permeability class Moderately rapid to very rapid Soil depth 60 – 0 in Surface fragment cover <=3" 10 – 50 % Surface fragment cover >3" 0 – 35 % Available water capacity
(0-40in)1.2 – 1.5 in Calcium carbonate equivalent
(0-40in)6 – 10 % Electrical conductivity
(0-40in)0 – 2 mmhos/cm Soil reaction (1:1 water)
(0-40in)7.9 – 8.4 Subsurface fragment volume <=3"
(Depth not specified)25 – 65 % Subsurface fragment volume >3"
(Depth not specified)0 – 35 % Ecological dynamics
Sandy Wash, 6"-9" p.z., is a shrub dominated ecological site. Sparse perennial grasses and forbs are occasionally encountered. Annual forbs and grasses flourish following rainfall. Other than frequent flash flooding, natural disturbances are rare. After introduction of non-native annuals (forbs and/or grasses), they persist on this site. Dominant shrubs are creosote and hymenochlea. Assorted half-shrubs are widely scattered.
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 textState 1 submodel, plant communities
State 2 submodel, plant communities
State 1
Historic NativeCommunity 1.1
Historic Native Plant CommunityThe dominant aspect of this site is a desert shrub.
This site is dominated by catclaw acacia, white burrobrush, and creosotebush. Perennial grasses are present in minor amounts.
The burrobrush on this site will increase if other plants decrease for any reason. Also, if plant cover is lost there will be an increase in channel depth and erosion.Figure 4. 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 109 263 381 Grass/Grasslike 8 33 67 Forb 8 25 44 Tree 0 4 8 Total 125 325 500 Table 6. Ground cover
Tree foliar cover 0% Shrub/vine/liana foliar cover 0-0% Grass/grasslike foliar cover 0-0% Forb foliar cover 0-0% 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 – – – 0-2% >0.5 <= 1 – – 0-2% – >1 <= 2 – – – – >2 <= 4.5 – – – – >4.5 <= 13 – 10-14% – – >13 <= 40 – – – – >40 <= 80 – – – – >80 <= 120 – – – – >120 – – – – Figure 5. Plant community growth curve (percent production by month). AZ3022 , 30.2 6-9" p.z. upland sites. Growth begins in the late winter, most growth occurs in the spring..
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 2 19 33 18 7 7 11 3 0 0 0 Figure 6. Plant community growth curve (percent production by month). AZ3030 , 40-3AZ 7-10" p.z. big galleta. Growth begins in the spring, goes dormant in May through June, most growth occurs during the summer rainy season..
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 0 10 10 0 0 15 55 10 0 0 0 State 2
Historic Native Plant Community plus Introduced AnnualsCommunity 2.1
Non-native AnnualsThis plant community resembles the historic native plant community, but exotic annuals have been introduced. Non-native species include Asian mustard (Brassica tournefortii), red brome, Mediterranean grass (Schismus spp.), and filaree. The flourish of non-native annuals that occurs following rainfalls may preclude native annuals.
Transition T1A
State 1 to 2Introduction of non-native annual forb and grass seed.
Additional community tables
Table 8. Community 1.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Grass/Grasslike1 3–16 big galleta PLRI3 Pleuraphis rigida 3–16 – 2 0–3 threeawn ARIST Aristida 0–3 – 3 0–6 sand dropseed SPCR Sporobolus cryptandrus 0–6 – 4 0–6 slim tridens TRMU Tridens muticus 0–6 – 5 3–16 Grass, annual 2GA Grass, annual 3–16 – Forb6 3–10 desert globemallow SPAM2 Sphaeralcea ambigua 3–10 – 7 3–16 Forb, annual 2FA Forb, annual 3–16 – 8 3–10 Forb, perennial 2FP Forb, perennial 3–10 – Shrub/Vine9 16–49 catclaw acacia ACGR Acacia greggii 16–49 – 10 65–98 burrobrush HYSA Hymenoclea salsola 65–98 – 11 32–64 creosote bush LATR2 Larrea tridentata 32–64 – 12 3–16 water jacket LYAN Lycium andersonii 3–16 – 13 0–6 burrobush AMDU2 Ambrosia dumosa 0–6 – 14 3–16 Nevada jointfir EPNE Ephedra nevadensis 3–16 – 15 3–10 Eastern Mojave buckwheat ERFAP Eriogonum fasciculatum var. polifolium 3–10 – 16 0–6 woolly fruit bur ragweed AMER Ambrosia eriocentra 0–6 – 17 0–6 purple sage SADO4 Salvia dorrii 0–6 – 18 0–3 peach thorn LYCO2 Lycium cooperi 0–3 – 19 0–3 brittlebush ENFA Encelia farinosa 0–3 – 20 0–10 pricklypear OPUNT Opuntia 0–10 – 21 0–6 rayless goldenhead ACSP Acamptopappus sphaerocephalus 0–6 – 22 0–10 button brittlebush ENFR Encelia frutescens 0–10 – 23 0–13 turpentinebroom THMO Thamnosma montana 0–13 – 24 0–10 Mexican bladdersage SAME Salazaria mexicana 0–10 – 25 0–3 desert almond PRFA Prunus fasciculata 0–3 – 26 3–16 Shrub (>.5m) 2SHRUB Shrub (>.5m) 3–16 – Tree27 0–6 Joshua tree YUBR Yucca brevifolia 0–6 – Table 9. Community 2.1 plant community composition
Group Common name Symbol Scientific name Annual production () Foliar cover (%) Interpretations
Animal community
Wildlife Species List:
Snakes, Lizards, Ground Squirrels, Blacktail Jackrabbit, Cottontail RabbitSupporting information
Type locality
Location 1: Mohave County, AZ Township/Range/Section T27 N. R20 W. S20 Latitude 35° 43′ 30″ Longitude 114° 27′ 30″ General legal description Mt. Tipton 3NW Quad - Sec. 20, T. 27 N., R. 20 W.; Lat. 35 43' 30", Long. 114 27' 30"; Mohave County, Arizona. Location 2: Mohave County, AZ Township/Range/Section T36 N. R16 W. S35 General legal description Pakoon Wash on Pakoon Springs Ranch; Sec. 35, T. 36 N., R. 16 W.; Mohave County, Arizona. Contributors
Harmon Hodgkinson
Harmon S. Hodgkinson
Larry D. Ellicott
Stephen CassadyApproval
Kendra Moseley, 10/21/2024
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 04/19/2026 Approved by Approval date Composition (Indicators 10 and 12) based on Annual Production Indicators
-
Number and extent of rills:
-
Presence of water flow patterns:
-
Number and height of erosional pedestals or terracettes:
-
Bare ground from Ecological Site Description or other studies (rock, litter, lichen, moss, plant canopy are not bare ground):
-
Number of gullies and erosion associated with gullies:
-
Extent of wind scoured, blowouts and/or depositional areas:
-
Amount of litter movement (describe size and distance expected to travel):
-
Soil surface (top few mm) resistance to erosion (stability values are averages - most sites will show a range of values):
-
Soil surface structure and SOM content (include type of structure and A-horizon color and thickness):
-
Effect of community phase composition (relative proportion of different functional groups) and spatial distribution on infiltration and runoff:
-
Presence and thickness of compaction layer (usually none; describe soil profile features which may be mistaken for compaction on this site):
-
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:
-
Amount of plant mortality and decadence (include which functional groups are expected to show mortality or decadence):
-
Average percent litter cover (%) and depth ( in):
-
Expected annual annual-production (this is TOTAL above-ground annual-production, not just forage annual-production):
-
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:
-
Perennial plant reproductive capability:
Print Options
Sections
Font
AAAAOther
PrintThe Ecosystem Dynamics Interpretive Tool is an information system framework developed by the USDA-ARS Jornada Experimental Range, USDA Natural Resources Conservation Service, and New Mexico State University.
Accessibility statement
