Vegetation and Substrate on Aeolian Landscapes in the 

Colorado River Corridor, Cataract Canyon, Utah

Open-File Report 2010-1273

U.S. Department of the Interior 

U.S. Geological Survey 

Vegetation and Substrate on Aeolian Landscapes in the 

Colorado River Corridor, Cataract Canyon, Utah

By Amy E. Draut and Elizabeth R. Gillette 

Open-File Report 2010-1273

U.S. Department of the Interior 

U.S. Geological Survey
U.S. Department of the Interior 

KEN SALAZAR, Secretary 

U.S. Geological Survey 

Marcia K. McNutt, Director 

U.S. Geological Survey, Reston, Virginia 2010 

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Suggested citation: 

Draut, A.E., and Gillette, E.R., 2010, Vegetation and substrate on aeolian landscapes in the Colorado River

 corridor, Cataract Canyon, Utah: U.S. Geological Survey Open-File Report 2010-1273, 61 p. and 14 spreadsheets

[http://pub.usgs.gov/of/2010/1273/].

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reproduce any copyrighted material contained within this report.
iii

Contents

Abstract.......................................................................................................................1 

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

Project Objectives..........................................................................................................4 

Methods......................................................................................................................5 

Results and Discussion..................................................................................................8 

Conclusions................................................................................................................18

Acknowledgments........................................................................................................19 

References Cited.........................................................................................................19 

Figures

1. Study sites in the Colorado River through Cataract Canyon, Utah. ..............................3 

2. Scale diagram of “pod” configuration used to map vegetation and substrate in 

Cataract Canyon..........................................................................................................6 

3. Measuring vegetation and substrate properties on an aeolian landscape in Cataract 

Canyon........................................................................................................................8 

4. Plots showing total vegetation cover. ..........................................................................11 

5. Plots showing total gap length.....................................................................................12 

6. Plots showing biologic crust abundance......................................................................12 

7. Plots showing substrate composition at each of the 13 study sites..............................13 

8. Plots showing coverage of invasive Russian thistle (Salsola sp.). ..............................14 

9. Plots showing coverage of invasive brome grasses (Bromus sp.). ..............................14 

10. Plots showing coverage of invasive tamarisk (Tamarix sp.). ......................................15 

11. Plots showing vegetation composition at each of the 13 study sites, identifying the 

proportion of Tamarix, Bromus, and Salsola............................................................16 
iv

Tables

1. Details of Cataract Canyon study sites. .................................................................21 

2. Vegetation cover and substrate properties measured at Site 1...............................22 

3. Vegetation cover and substrate properties measured at Site 2...............................25 

4. Vegetation cover and substrate properties measured at Site 3...............................28 

5. Vegetation cover and substrate properties measured at Site 4...............................31 

6. Vegetation cover and substrate properties measured at Site 5...............................35 

7. Vegetation cover and substrate properties measured at Site 6...............................38 

8. Vegetation cover and substrate properties measured at Site 7...............................41 

9. Vegetation cover and substrate properties measured at Site 8...............................44 

10. Vegetation cover and substrate properties measured at Site 9...............................47 

11. Vegetation cover and substrate properties measured at Site 10.............................50 

12. Vegetation cover and substrate properties measured at Site 11.............................53 

13. Vegetation cover and substrate properties measured at Site 12.............................56 

14. Vegetation cover and substrate properties measured at Site 13.............................59 
Vegetation and Substrate on Aeolian Landscapes in the 

Colorado River Corridor, Cataract Canyon, Utah

By Amy E. Draut1 and Elizabeth R. Gillette2

Abstract 

Vegetation and substrate data presented in this report characterize ground cover on aeolian 

landscapes of the Colorado River corridor through Cataract Canyon, Utah, in Canyonlands National 

Park. The 27-km-long Cataract Canyon reach has undergone less anthropogenic alteration than other 

reaches of the mainstem Colorado River. Characterizing ecosystem parameters there provides a basis 

against which to evaluate future changes, such as those that could result from the further spread of 

nonnative plant species or increased visitor use. Upstream dams have less effect on the hydrology and 

sediment supply in Cataract Canyon compared with downstream reaches in Grand Canyon National 

Park. For this reason, comparison of these vegetation and substrate measurements with similar data 

from aeolian landscapes of Grand Canyon will help to resolve the effects of Glen Canyon Dam 

operations on the Colorado River corridor ecosystem. 

Introduction 

Most areas of the Colorado River corridor, in the southwestern United States, are affected by 

human-caused alteration, whether from changes in river flow and sediment supply caused by upstream 

dams, from introduced plant and animal species, or from land use in the watershed that includes 

 

1

 U.S. Geological Survey Pacific Coastal and Marine Science Center, Santa Cruz, CA 95060 

2

 2 Thissell Rd., Ossipee, NH 03864 
2

agricultural and rangeland practices. The 27-km reach of the Colorado River corridor through Cataract 

Canyon, Utah (fig. 1), represents the least altered region along the mainstem Colorado River below its 

confluence with the major Green River tributary. Because its hydrology and sediment supply are less 

affected by upstream dams than are any reaches of the Colorado River farther downstream, and because 

the immediately surrounding watershed is nearly undeveloped as part of Canyonlands National Park, 

Cataract Canyon provides an opportunity to study natural resources in an ecosystem less disturbed than 

in many other parts of the Colorado River corridor. This field study quantified ground cover (vegetation 

and substrate) on landscapes of Cataract Canyon that are characterized by aeolian (wind-blown) sand. 
3

Figure 1. Study sites (numbered circles) in the Colorado River corridor through Cataract Canyon, Utah. Site 

descriptions are given in table 1. River miles of Belknap and others (2008) are shown. Inset map shows 

Cataract Canyon (box) in the context of the Colorado River basin (shaded region). Major dams of the Colorado 

River and its tributaries are shown as black bars on the inset map. 
4

Project Objectives 

The objective of this field study was to measure vegetation and substrate properties in aeolian 

dune fields within the Colorado River corridor through Cataract Canyon, Canyonlands National Park. 

Vegetative cover, native and nonnative species assemblages, and substrate composition including 

biologic crust extent are described in this report to further the ecosystem-monitoring efforts undertaken 

by Canyonlands National Park. These data will also be compared, in a separate publication, with 

ground-cover measurements made on aeolian landscapes of the Colorado River corridor in Grand 

Canyon National Park, a reach of the river affected substantially by flow regulation and sedimentsupply limitations owing to Glen Canyon Dam operations. 

This work in Cataract Canyon, upstream of Glen Canyon Dam and its reservoir, Lake Powell, 

constitutes part of a larger study of the effects of Glen Canyon Dam on the Colorado River corridor. 

Previous studies have shown that Glen Canyon Dam operations substantially reduced the size and 

number of fluvial sand deposits in Grand Canyon (Kearsley and others, 1994; Rubin and others, 2002; 

Wright and others, 2005; Hazel and others, 2006). Because fluvial sandbars are the primary source for 

sand that moves inland by wind and forms aeolian dune fields, the loss of fluvial sand, in turn, can 

reduce the supply of wind-blown sediment to aeolian dune fields downwind (Neal and others, 2000; 

Draut and Rubin, 2008; Draut and others, 2008, 2010) with possible consequences for ecosystems in 

those aeolian landscapes. To assess the degree to which sediment-supply limitation in Grand Canyon 

has affected conditions in aeolian landscapes there, it will therefore be informative to compare 

vegetation and substrate in aeolian dunes of Grand Canyon with those of Cataract Canyon, where 

hydrology and sediment supply more closely resemble natural conditions (see, for example, an earlier 

comparative geomorphic study by Thompson and Potochnik, 2000). 
5

Methods 

This study focused on the Cataract Canyon reach of the Colorado River corridor in Canyonlands 

National Park, between the confluence of the Green and Colorado Rivers and the recent upstream extent 

of Lake Powell in the area of Imperial Canyon (fig. 1). Vegetation cover (percent cover and vegetation 

type) and substrate were measured at 13 sites during July 2010. Study sites were chosen within 

landscapes dominated by aeolian geomorphology, above and within 100 m of the highest elevation of 

recent fluvial sand deposition. The peak stage of the spring flood in June 2010 (1,530 m3

/s) was readily 

identifiable by the presence of driftwood, vegetation debris in wrack lines, and sandbar morphology that 

commonly formed separation and reattachment bars associated with eddies (Schmidt, 1990). On the 

basis of aeolian landforms (sand dunes, coppice dunes, and sand shadows behind rocks and vegetation), 

erosion, transport, and deposition by wind appeared to have been the dominant sedimentary processes 

recently affecting the study sites. The source of aeolian sediment at the study sites was inferred to have 

been a combination of new sand recently transported inland from spring flood deposits situated at lower 

elevation and upwind of the sites and wind reworking of sediment from older, larger flood deposits that 

underlie the sites (known from the presence of old driftwood logs and flood debris inland of most study 

sites). 

Table 1 lists site numbers, names, locations, and descriptions. At Sites 1, 3, 5, and 12, ground 

cover appeared to be affected somewhat by camping activity, such as the presence of tent sites (Sites 1, 

3, and 5) or a trail (Site 12). Sites 3 and 4 were established in the same dune field, one (Site 3) in an area 

affected by camp activity and the other (Site 4) apparently unaffected. Sites 5 and 6, similarly, represent 

camp and noncamp areas within one dune field. Although areas affected by camping activity cannot be 
6

considered to have entirely natural conditions, they were included in this study in order to represent the 

range of ground cover in Cataract Canyon’s aeolian landscapes as completely as possible. 

Vegetation and substrate were measured at each site by establishing a layout of circles and linear 

transects referred to here as a “pod.” As shown in figure 2, each pod consisted of two orthogonal 

transects marked out with a tape reel (one oriented upstream-to-downstream and the other oriented 

inland-to-riverward) and five circles outlined in the sand (one in the center of the pod and one at the end 

of each of the four transects). At study sites within small dune fields, the pods used transects 20 m long, 

whereas in larger dune fields the pods used transects 40 m long (table 1). For both the smaller (20 x 20 

m) and larger (40 x 40 m) pod size, the five circles were always the same size, having a 3-m radius (fig. 

2). 

Figure 2. Scale diagram of “pod” configuration used to map vegetation and substrate in Cataract Canyon. Two 

transects of length 20 m and five circles of radius 3 m were used in small dune fields (as shown here). In study 
7

sites with larger dune fields, the pod configuration included two transects of length 40 m and five circles of 

radius 3 m. 

Along each of the transects within a pod, we measured the lengths of all gaps where the 

measuring tape crossed bare, open sand without rocks, biologic crust, leaf litter, or overhanging plant 

canopy. This method was modified from Herrick and others (2005), using their criteria to define plant 

canopy gaps, as a means to measure the spacing and abundance of roughness elements, vegetation, and 

patches of biologic crust that affect aeolian sediment mobility (Ash and Wasson, 1983; Buckley, 1987; 

Leys and Eldridge, 1998; Belnap, 2003; Goossens, 2004). The proportion of bare, open sand in the dune 

field can thus be estimated by adding all of the measured gap lengths from each transect to compile a 

cumulative gap length measurement and representing that total gap length as a percentage of the total 

transect length. 

Within each of the five circles per pod, we measured the proportion of space occupied by 

vegetation (categorized at the species level wherever possible) and various types of substrate in which 

vegetation was growing. Substrate was considered in four categories: open sand, biologic soil crust, leaf 

litter (including driftwood, at some sites), and rock (fig. 3). We did not distinguish among the different 

species of biologic crust known to occur in Cataract Canyon (Webb and others, 2004). To estimate 

percent coverage, we compared a disc of known size with the area covered by a plant, rock, patch of soil 

crust, or other object of interest. The disc (radius 20 cm) has an area (0.13 m2

) approximately half of one 

percent of the circle size studied (28.3 m2

). By holding a disc of known radius above plants or crust 

cover to gage their size and percent coverage, we avoided disturbing the ground surface unnecessarily as 

would happen from handling plants or placing measuring devices (such as plastic grids) directly on 

sensitive, soil-encrusted ground. Field sites were photographed, transect orientations were measured 
8

with a compass, and recent dominant wind directions were estimated by using compass measurements 

of dune slipface and sand-shadow orientations (table 1). All equipment was removed when the work 

was completed at each site. 

 

Figure 3. Measuring vegetation and substrate properties on an aeolian landscape in Cataract Canyon (Site 13), 

summer 2010. 

Results and Discussion 

Tables 2–14 list vegetation and substrate properties measured at the 13 Cataract Canyon study 

sites. Vegetation was identified to species level wherever possible, using names and descriptions given 

by Taylor (1992), Williams (2000), and Huisinga and others (2006). In cases where species 
9

identification was unclear, plants were identified by their family or genus, or by designation as annual or 

perennial grass, forb, or shrub. 

Figure 4 summarizes vegetation cover. Sites where camping activity was apparent did not have 

substantially different vegetation coverage from study sites without camping activity (median vegetation 

coverage was 20.2 percent among the 4 sites with camp activity, compared with a median value of 23.1 

percent for the noncamp sites and 22.4 percent for all 13 sites). The sites with camp activity had more 

open, bare sand than was characteristic of most noncamp study sites, judging from differences in total 

gap length (fig. 5). Median total gap length among the 4 sites with evidence of camp use was 78.7 

percent, compared with 66.0 percent among the 9 noncamp sites and 68.8 percent for all 13 sites. 

Differences in the amount of open sand between sites with and without camp activity are largely 

attributable to differences in biologic crust coverage. As a group, the sites used as camps had less 

biologic crust than noncamp areas (fig. 6), with lower median values (1.53 percent for the sites with 

camp activity compared to 2.80 percent for sites without camp activity) and a much lower maximum 

extent (4.00 percent among the sites with camp activity compared to 37.4 percent among the noncamp 

sites; fig. 6). Notably, the site with the most biologic crust (Site 6) is only a short distance away from an 

area used as a camp, with the center of the Site 6 pod being 50 m inland of the recent spring high-water 

line near a large camp. Apart from one prominent trail (not near the study pod), visitor use apparently 

had not disturbed areas with abundant biologic soil crust a short distance away from the camp at Site 6. 

Substrate composition at all 13 study sites is shown in figure 7. 

Diverse vegetation assemblages were recorded at the study sites, with most aeolian landscapes 

containing between 10 and 20 different species. Among the native plant varieties, perennial bunchgrasses such as rice grass (Oryzopsis hymenoides, also known as genus Achnatherum or Stipa) and 

several species of dropseed (Sporobolus) were common, as were Ephedra shrubs, wire lettuce 
10

(Stephanomeria pauciflora), snakeweed (Gutierrezzia sp.), forbs such as sand verbena (Abronia 

elliptica), dicoria (Dicoria canescens), and globemallow (Sphaeralcea sp.), and several members of the 

Asteraceae/Compositae family. 

Every site contained at least one nonnative plant variety within the study pod. The three 

nonnative plants most commonly identified were Russian thistle (tumbleweed, Salsola), brome grasses 

(genus Bromus; we did not distinguish among varieties such as cheat grass, ripgut brome, and brown 

brome), and tamarisk trees (Tamarix). Each of these is able to spread rapidly and is considered an 

invasive plant in southwest desert ecosystems. Salsola and Bromus are especially adept at colonizing 

disturbed ground surfaces (D’Antonio and Vitousek, 1992; Belnap and others, 2009). Tamarisk and 

brome grasses were commonly associated with one another at the Cataract Canyon study sites, with the 

nonnative brome growing abundantly under tamarisk trees. Nearly all tamarisk had brown leaves and 

many tamarisk beetles (Diorhabda elongata), which land-management agencies introduced between 

2005 and 2010 in an effort to curb the spread of tamarisk. Figures 8, 9, and 10 show the total area 

covered by Salsola, Bromus, and Tamarix, respectively, at the study sites. There do not appear to be 

substantial differences among sites with camp activity and those without, though the maximum 

coverage of Salsola and Bromus was highest at a noncamp site (Site 6). The apparently greater coverage 

of tamarisk at sites with camp activity (fig. 10) is likely due to both tamarisk and human visitors 

preferring locations near the river. The smaller number of study sites with camp activity may make it 

difficult to resolve other patterns in nonnative species prevalence that might exist between camp and 

noncamp areas. Figure 11 illustrates the proportions of Salsola, Bromus, and Tamarix at each study site 

relative to all other types of vegetation. In several places those plant varieties account for a substantial 

proportion of the vegetation community; notably, at Sites 3, 5, and 6, invasive Salsola, Bromus, and 

Tamarix together make up well over half of the total vegetation (fig. 11). 
11

 

Figure 4. Box-and-whisker plots showing total area of vegetation cover, in percent, for the 4 study sites affected 

by camping activity (Sites 1, 3, 5, and 12), the 9 noncamp study sites, and all 13 sites combined. Length of 

each box spans the interquartile range (first quartile to third quartile) of the data; horizontal line through each 

box represents the median value. Circles mark outlier data points (those more than 1.5 times the interquartile 

range). Whiskers mark highest and lowest non-outlier data points. 
12

 

Figure 5. Box-and-whisker plots showing total gap length, as a percent of total transect length, for the 4 study 

sites affected by camping activity (Sites 1, 3, 5, and 12), the 9 noncamp study sites, and all 13 sites combined. 

 

Figure 6. Box-and-whisker plots showing biologic soil crust abundance, as a percent of total substrate, for the 4 

study sites affected by camping activity (Sites 1, 3, 5, and 12), the 9 noncamp study sites, and all 13 sites 

combined. 
13

 

Figure 7. Substrate composition at each of the 13 study sites. Site numbers are listed below columns. 
14

 

Figure 8. Box-and-whisker plots showing coverage of invasive Russian thistle (Salsola sp.) at the 4 study sites 

affected by camping activity (Sites 1, 3, 5, and 12), the 9 noncamp study sites, and all 13 sites combined. 

 

Figure 9. Box-and-whisker plots showing coverage of invasive brome grasses (Bromus sp.) at the 4 study sites 

affected by camping activity (Sites 1, 3, 5, and 12), the 9 noncamp study sites, and all 13 sites combined. 
15

 

Figure 10. Box-and-whisker plots showing coverage of invasive tamarisk (Tamarix sp.) at the 4 study sites affected 

by camping activity (Sites 1, 3, 5, and 12), the 9 noncamp study sites, and all 13 sites combined. 
16

 

Figure 11. Vegetation composition, in percent areal coverage, at each of the 13 study sites, identifying the 

proportions of three prominent invasive plant types (Tamarix, Bromus, and Salsola). 

Conclusions 

Vegetation and substrate data presented here characterize ground cover on aeolian landscapes of 

the Colorado River corridor through Cataract Canyon, Utah. Some changes to the natural ecosystem 

likely have resulted from human camping use, notably the lower abundance of biologic soil crust and 

correspondingly more open, bare sand in dune fields that sustain some camp activity compared to those 

that do not. Nonnative vegetation was present among the plant communities at each of the 13 study 

sites. Invasive Salsola, Bromus, and Tamarix now compose a substantial proportion of the plant 

community in Cataract Canyon’s aeolian landscapes. 
17

These data can form a basis against which to evaluate future changes in the Cataract Canyon 

ecosystem, the least disturbed region of the Colorado River corridor below the confluence with its 

largest tributary, the Green River. Upstream dams have less effect on the hydrology and sediment 

supply in Cataract Canyon compared to downstream reaches in Grand Canyon National Park. For this 

reason, comparison of these vegetation and substrate measurements with similar data from aeolian 

landscapes of Grand Canyon will help to resolve the effects of Glen Canyon Dam operations on the 

Colorado River corridor ecosystem. 

Acknowledgments 

This work was conducted under National Park Service Research and Collecting permit CANY2010-SCI-0003. The authors thank John Weisheit for providing logistical field support and sharing his 

greatly detailed knowledge of Cataract Canyon’s natural and human history. R.L. Reynolds and C.D. 

Storlazzi provided constructive review comments that improved this report. 

References Cited 

Ash, J.E., and Wasson, R.J., 1983, Vegetation and sand mobility in the Australian desert dunefield: 

Zeitschrift für Geomorphologie, supp. v. 45, p. 7–25. 

Belknap, B., Belknap, B., and Evans, L.B., 2008, Belknap’s waterproof Canyonlands river guide: 

Evergreen, Colo., Westwater Books, 77 p., ISBN-13:978-0-916370-17-6. 

Belnap, J., 2003, Biological soil crusts and wind erosion, in Belnap, J., and Lange, O.L., eds., Biological 

soil crusts—structure, function, and management: Berlin, Springer-Verlag, Ecological Studies 

series, v. 150, p. 339–347. 
18

Belnap, J., Reynolds, R.L., Reheis, M.C., Phillips, S.L., Urban, F.E., and Goldstein, H.L., 2009, 

Sediment losses and gains across a gradient of livestock grazing and plant invasion in a cool, 

semi-arid grassland, Colorado Plateau, USA: Aeolian Research, v. 1, p. 27–43. 

Buckley, R., 1987, The effect of sparse vegetation on the transport of dune sand by wind: Nature, v. 

325, p. 426–428. 

D’Antonio, C.M., and Vitousek, P.M., 1992, Biological invasions by exotic grasses, the grass/fire cycle, 

and global change: Annual Review of Ecology and Systematics, v. 23, p. 63–87. 

Draut, A.E., and Rubin, D.M., 2008, The role of eolian sediment in the preservation of archeologic sites 

along the Colorado River corridor in Grand Canyon National Park, Arizona: U.S. Geological 

Survey Professional Paper 1756, 71 p., accessed December 6, 2010, at 

http://pubs.usgs.gov/pp/1756/.

Draut, A.E., Rubin, D.M., Dierker, J.L., Fairley, H.C., Griffiths, R.E., Hazel, J.E., Jr., Hunter, R.E., 

Kohl, K., Leap, L.M., Nials, F.L., Topping, D.J., and Yeatts, M., 2008, Application of 

sedimentary-structure interpretation to geoarchaeological studies in the Colorado River corridor, 

Grand Canyon, Arizona, USA: Geomorphology, v. 101, no. 3, p. 497–509. 

Draut, A.E., Sondossi, H.A., Dealy, T.P., Hazel, J.E., Jr., Fairley, H.C., and Brown, C.R., 2010, 2009 

weather and aeolian sand-transport data from the Colorado River corridor, Grand Canyon, 

Arizona: U.S. Geological Survey Open-File Report 2010-1166, 98 p., accessed December 6, 2010, 

at http://pubs.usgs.gov/of/2010/1166/. 

Goossens, D., 2004, Effect of soil crusting on the emission and transport of wind-eroded sediment—

field measurements on loamy sandy soil: Geomorphology, v. 58, p. 145–160. 
19

Hazel, J.E., Jr., Topping, D.J., Schmidt, J.C., and Kaplinski, M., 2006, Influence of a dam on finesediment storage in a canyon river: Journal of Geophysical Research v. 111, no. F3, doi: 

10.1029/2004JF000193. 

Herrick, J.E., Van Zee, J.W., Havstad, K.M., Burkett, L.M., and Whitford, W.G., 2005, Monitoring 

manual for grassland, shrubland, and savanna ecosystems: Las Cruces, New Mexico, U.S. 

Department of Agriculture, distributed by University of Arizona Press, 36 p. 

Huisinga, K., Makarick, L., and Watters, K., 2006, River and desert plants of the Grand Canyon: 

Missoula, Montana, Mountain Press Publishing Company, 261 p. 

Kearsley, L.H., Schmidt, J.C., and Warren, K.D., 1994, Effects of Glen Canyon Dam on Colorado River 

sand deposits used as campsites in Grand Canyon National Park, USA: Regulated Rivers, 

Research and Management, v. 9, p. 137–149. 

Leys, J.F., and Eldridge, D.J., 1998, Influence of cryptogamic crust disturbance to wind erosion on sand 

and loam rangeland soils: Earth Surface Processes and Landforms, v. 23, p. 963–974. 

Neal, L.A., Gilpin, D., Jonas, L., and Ballagh, J.H., 2000, Cultural resources data synthesis within the 

Colorado River corridor, Grand Canyon National Park and Glen Canyon National Recreation 

Area, Arizona: SWCA, Inc., Cultural Resources Report 98-85. 

Rubin, D.M., Topping, D.J., Schmidt, J.C., Hazel, J., Kaplinski, M., and Melis, T.S., 2002, Recent 

sediment studies refute Glen Canyon Dam hypothesis: Eos (American Geophysical Union 

Transactions), v. 83, p. 273, 277–278. 

Schmidt, J.C., 1990, Recirculating flow and sedimentation in the Colorado River in Grand Canyon, 

Arizona: Journal of Geology, v. 98, p. 709–724. 
20

Taylor, R.J., 1992, Sagebrush country; a wildflower sanctuary: Missoula, Montana, Mountain Press 

Publishing Company, 209 p. 

Thompson, K.S., and Potochnik, A.R., 2000, Development of a geomorphic model to predict erosion of 

pre-dam Colorado River terraces containing archaeological resources: SWCA, Inc. Cultural 

Resources Report 99-257. 

Webb, R.H., Belnap, J., and Weisheit, J.S., 2004, Cataract Canyon—a human and environmental history 

of the rivers in Canyonlands: University of Utah Press, 268 p. 

Williams, D.B., 2000, A naturalist’s guide to canyon country: Guilford, Conn., Globe Pequot Press, 188 

p. 

Wright, S.A., Melis, T.S., Topping, D.J., and Rubin, D.M., 2005, Influence of Glen Canyon Dam 

operations on downstream sand resources of the Colorado River in Grand Canyon, in Gloss, S.P., 

Lovich, J.E., and Melis, T.S., eds., The state of the Colorado River ecosystem in Grand Canyon: 

U.S. Geological Survey Circular 1282, p. 17–31. 
Table 1. Details of Cataract Canyon study sites. 

[Site names refer to the name of the rapid, camp, or side canyon nearest them, and to whether the site is on the left or right side of

the river when viewed facing downstream. Wind direction is interpreted to be the recent dominant direction from which the wind came,

estimated by measuring azimuth orientations of dune slipfaces and sand shadows behind rocks, vegetation, or other obstacles.]

Site 

Number Site Name Latitude Longitude Pod Size

Camp 

Activity?

Wind 

Direction

1 Brown Betty, Right 38 ̊08'52.43"N 109 ̊55'40.38"W 40 x 40 m Yes 190–220 ̊

2 Lower 2, Right 38 ̊08'40.36"N 109 ̊55'44.52"W 40 x 40 m No 149–183 ̊

3 Rapid 5, Right (camp pod) 38 ̊08'06.28"N 109 ̊56'44.99"W 40 x 40 m Yes 205–224 ̊

4 Rapid 5, Right (noncamp pod) 38 ̊08'07.47"N 109 ̊56'41.25"W 20 x 20 m No 205–224 ̊

5 Lower 5, Right (camp pod) 38 ̊07'56.61"N 109 ̊57'08.47"W 40 x 40 m Yes 200–235 ̊

6 Lower 5, Right (noncamp pod) 38 ̊07'57.34"N 109 ̊57'07.75"W 40 x 40 m No 200–235 ̊

7 Upper Tilted Park, Left 38 ̊06'46.23"N 109 ̊57'53.06"W 40 x 40 m No 265–274 ̊

8 Lower Y, Right 38 ̊06'47.60"N 109 ̊58'08.96"W 40 x 40 m No 265–274 ̊

9 Big Drop Beach, Left 38 ̊05'00.52"N 110 ̊02'12.23"W 20 x 20 m No 240–250 ̊

10 Upper 25, Right 38 ̊03'55.84"N 110 ̊02'40.53"W 20 x 20 m No 101–165 ̊

11 Lower 25, Right 38 ̊03'51.47"N 110 ̊02'41.78"W 40 x 40 m No 130–159 ̊

12 Ten Cent Camp, Left 38 ̊03'22.50"N 110 ̊02'33.69"W 20 x 20 m Yes 175–208 ̊

13 Lower Ten Cent, Left 38 ̊03'09.81"N 110 ̊02'35.80"W 20 x 20 m No 194–230 ̊

21
Table 2. Vegetation cover and substrate measured at Site 1 (Brown Betty, Right).

Center Circle Vegetation Percent Cover

None

Total 0

Substrate Percent Cover

Sand 100

Rock 0

Leaf litter 0

Biologic soil crust 0

Upstream Circle Vegetation Percent Cover

Netleaf hackberry (Celtis laevigata) 17.0

Snakeweed (Gutierrezzia sp.) 3.75

Broadleaf milkweed (Asclepias latifolia) 2.00

Wire lettuce (Stephanomeria pauciflora) 1.75

Rice grass (Oryzopsis hymenoides) 1.75

Unidentified legume 1.00

Unidentified annual forb 1.00

Russian thistle (Salsola sp.) 0.13

Total 28.4

Substrate Percent Cover

Sand 87.3

Rock 12.5

Leaf litter 0

Biologic soil crust 0.25

22
Table 2. Vegetation cover and substrate measured at Site 1 (Brown Betty, Right)—Continued.

Downstream Circle Vegetation Percent Cover

Dropseed (Sporobolus sp.) 0.75

Russian thistle (Salsola sp.) 0.18

Brome grasses (Bromus sp.) 0.13

Unidentified annual grass 0.05

Total 1.10

Substrate Percent Cover

Sand 90.9

Rock 9.00

Leaf litter 0.10

Biologic soil crust 0

Inland Circle Vegetation Percent Cover

Ephedra (Ephedra sp.) 25.0

Brome grasses (Bromus sp.) 3.50

Snakeweed (Gutierrezzia sp.) 2.75

Prince's plume (Stanleya pinnata) 1.00

Bladderpod (Lesquerella sp.) 1.00

Prickly pear (Opuntia sp.) 0.10

Total 33.4

Substrate Percent Cover

Sand 64.0

Rock 30.0

Leaf litter 0

Biologic soil crust 6.00

23
Table 2. Vegetation cover and substrate measured at Site 1 (Brown Betty, Right)—Continued.

Riverward Circle Vegetation Percent Cover

None

Total 0

Substrate Percent Cover

Sand 100

Rock 0

Leaf litter 0

Biologic soil crust 0

Total gap length on upstream/downstream transect (out of 4,000 cm): 3,283 cm

Total gap length on inland/riverward transect (out of 4,000 cm): 3,240 cm

Summary

Total vegetation cover, in percent 12.6

Total sand substrate, in percent 88.4

Total rock substrate, in percent 10.3

Total leaf litter substrate, in percent 0.02

Total biologic crust substrate, in percent 1.25

Total gap length, in percent 81.5

24
Table 3. Vegetation cover and substrate measured at Site 2 (Lower 2, Right).

Center Circle Vegetation Percent Cover

Rice grass (Oryzopsis hymenoides) 6.63

Unidentified perennial forb 4.50

Wire lettuce (Stephanomeria pauciflora) 2.90

Baccharis (Baccharis salicifolia) 1.00

Long-leaf brickellbush (Brickellia longifolia) 1.00

Rice grass (Oryzopsis hymenoides), dead 1.00

Unidentified aster/composite 0.25

Total 17.3

Substrate Percent Cover

Sand 90.8

Rock 9.25

Leaf litter 0

Biologic soil crust 0

Upstream Circle Vegetation Percent Cover

Brome grasses (Bromus sp.) 5.00

Snakeweed (Gutierrezzia sp.) 4.50

Ephedra (Ephedra sp.) 3.00

Unidentified perennial forb 1.50

Russian thistle (Salsola sp.) 0.75

Rice grass (Oryzopsis hymenoides) 0.25

Unidentified perennial grass 0.06

Total 15.1

Substrate Percent Cover

Sand 79.0

Rock 20.0

Leaf litter 1.00

Biologic soil crust 0

25
Table 3. Vegetation cover and substrate measured at Site 2 (Lower 2, Right)—Continued.

Downstream Circle Vegetation Percent Cover

Alfalfa (Medicago sativa) 0.15

Total 0.15

Substrate Percent Cover

Sand 53.0

Rock 47.0

Leaf litter 0

Biologic soil crust 0

Inland Circle Vegetation Percent Cover

Ephedra (Ephedra sp.) 22.0

Unidentified aster/composite 5.00

Snakeweed (Gutierrezzia sp.) 2.00

Brome grasses (Bromus sp.) 1.50

Bladderpod (Lesquerella sp.) 1.25

Dropseed (Sporobolus sp.) 1.00

Rice grass (Oryzopsis hymenoides) 0.75

Claret cup cactus (Echinocereus triglochidiatus) 0.50

Unidentified grass 0.25

Netleaf hackberry (Celtis laevigata) 0.25

Total 34.5

Substrate Percent Cover

Sand 35.0

Rock 40.0

Leaf litter 15.0

Biologic soil crust 10.0

26
Table 3. Vegetation cover and substrate measured at Site 2 (Lower 2, Right)—Continued.

Riverward Circle Vegetation Percent Cover

Tamarisk (Tamarix sp.) 22.5

Prince's plume (Stanleya pinnata) 7.50

Snakeweed (Gutierrezzia sp.) 4.63

Brome grasses (Bromus sp.) 1.75

Total 36.4

Substrate Percent Cover

Sand 61.9

Rock 16.1

Leaf litter 22.0

Biologic soil crust 0

Total gap length on upstream/downstream transect (out of 4,000 cm): 2,314 cm

Total gap length on inland/riverward transect (out of 4,000 cm): 1,626 cm

Summary

Total vegetation cover, in percent 20.7

Total sand substrate, in percent 63.9

Total rock substrate, in percent 26.5

Total leaf litter substrate, in percent 7.60

Total biologic crust substrate, in percent 2.00

Total gap length, in percent 49.3

27
Table 4. Vegetation cover and substrate measured at Site 3 (Rapid 5, Right, camp pod).

Center Circle Vegetation Percent Cover

Tamarisk (Tamarix sp.) 18.0

Russian thistle (Salsola sp.) 2.50

Rice grass (Oryzopsis hymenoides) 2.00

Sand verbena (Abronia elliptica) 1.60

Unidentified aster/composite 0.80

Brome grasses (Bromus sp.) 0.75

Total 25.7

Substrate Percent Cover

Sand 78.0

Rock 0

Leaf litter 22.0

Biologic soil crust 0

Upstream Circle Vegetation Percent Cover

Rice grass (Oryzopsis hymenoides) 2.00

Unidentified aster/composite 1.50

Sand verbena (Abronia elliptica) 1.50

Brome grasses (Bromus sp.) 0.75

Unidentified perennial forb, dead 0.40

Russian thistle (Salsola sp.) 0.25

Unidentified perennial forb 0.25

Total 6.15

Substrate Percent Cover

Sand 96.8

Rock 0

Leaf litter 0.50

Biologic soil crust 2.75

28
Table 4. Vegetation cover and substrate measured at Site 3 (Rapid 5, Right, camp pod)—Continued.

Downstream Circle Vegetation Percent Cover

Rice grass (Oryzopsis hymenoides) 3.25

Sand verbena (Abronia elliptica) 2.25

Unidentified aster/composite 2.00

Dropseed (Sporobolus sp.) 1.50

Spike dropseed (Sporobolus contractus) 0.90

Russian thistle (Salsola sp.) 0.75

Needle-and-thread (Stipa comata) 0.75

Brome grasses (Bromus sp.) 0.15

Total 11.6

Substrate Percent Cover

Sand 100

Rock 0

Leaf litter 0

Biologic soil crust 0

Inland Circle Vegetation Percent Cover

Brome grasses (Bromus sp.) 30.0

Tamarisk (Tamarix sp.) 12.0

Russian thistle (Salsola sp.) 3.75

Rice grass (Oryzopsis hymenoides) 0.60

Unidentified aster/composite 0.50

Dropseed (Sporobolus sp.) 0.25

Pale evening primrose (Oenothera pallida) 0.05

Total 47.2

Substrate Percent Cover

Sand 65.0

Rock 0

Leaf litter 35.0

Biologic soil crust 0

29
Table 4. Vegetation cover and substrate measured at Site 3 (Rapid 5, Right, camp pod)—Continued.

Riverward Circle Vegetation Percent Cover

Willow (Salix exigua) 0.75

Total 0.75

Substrate Percent Cover

Sand 100

Rock 0

Leaf litter 0

Biologic soil crust 0

Total gap length on upstream/downstream transect (out of 4,000 cm): 2,934 cm

Total gap length on inland/riverward transect (out of 4,000 cm): 2,636 cm

Summary

Total vegetation cover, in percent 18.4

Total sand substrate, in percent 88.0

Total rock substrate, in percent 0

Total leaf litter substrate, in percent 11.5

Total biologic crust substrate, in percent 0.55

Total gap length, in percent 69.6

30
Table 5. Vegetation cover and substrate measured at Site 4 (Rapid 5, Right, noncamp pod).

Center Circle Vegetation Percent Cover

Unidentified aster/composite 6.13

Rice grass (Oryzopsis hymenoides) 5.88

Dropseed (Sporobolus sp.) 1.00

Wire lettuce (Stephanomeria pauciflora) 0.50

Unidentified forbs 0.30

Ephedra (Ephedra sp.) 0.25

Pale evening primrose (Oenothera pallida) 0.25

Russian thistle (Salsola sp.) 0.05

Milkvetch (Astralagus sp.) 0.05

Brome grasses (Bromus sp.) 0.05

Total 14.5

Substrate Percent Cover

Sand 59.0

Rock 41.0

Leaf litter 0

Biologic soil crust 0

Upstream Circle Vegetation Percent Cover

Unidentified aster/composite 6.00

Rice grass (Oryzopsis hymenoides) 3.88

Brome grasses (Bromus sp.) 2.65

Dropseed (Sporobolus sp.) 1.25

Long-leaf brickellbush (Brickellia longifolia) 1.00

Ephedra (Ephedra sp.) 0.50

Milkvetch (Astralagus sp.) 0.38

Wire lettuce (Stephanomeria pauciflora) 0.38

Unidentified forbs 0.25

Snakeweed (Gutierrezzia sp.) 0.25

Pale evening primrose (Oenothera pallida) 0.05

Total 16.6

Substrate Percent Cover

Sand 47.0

Rock 52.0

Leaf litter 0

Biologic soil crust 1.00

31
Table 5. Vegetation cover and substrate measured at Site 4 (Rapid 5, Right, noncamp pod)—Continued.

Downstream Circle Vegetation Percent Cover

Tamarisk (Tamarix sp.) 5.00

Dropseed (Sporobolus sp.) 2.50

Rice grass (Oryzopsis hymenoides) 2.00

Unidentified legume 1.20

Brome grasses (Bromus sp.) 1.00

Globemallow (Sphaeralcea sp.) 0.80

Russian thistle (Salsola sp.) 0.75

Grama grass (Bouteloua sp.) 0.50

Pale evening primrose (Oenothera pallida) 0.15

Unidentified forb 0.10

Total 14.0

Substrate Percent Cover

Sand 67.5

Rock 20.0

Leaf litter 12.0

Biologic soil crust 0.50

32
Table 5. Vegetation cover and substrate measured at Site 4 (Rapid 5, Right, noncamp pod)—Continued.

Inland Circle Vegetation Percent Cover

Rice grass (Oryzopsis hymenoides) 3.13

Unidentified aster/composite 2.75

Snakeweed (Gutierrezzia sp.) 2.75

Wire lettuce (Stephanomeria pauciflora) 2.25

Dropseed (Sporobolus sp.) 1.00

Unidentified forb 1.00

Brome grasses (Bromus sp.) 0.75

Long-leaf brickellbush (Brickellia longifolia) 0.50

Pale evening primrose (Oenothera pallida) 0.38

Sand verbena (Abronia elliptica) 0.35

Unidentified perennial grass, dead 0.25

Milkvetch (Astralagus sp.) 0.05

Total 15.2

Substrate Percent Cover

Sand 55.3

Rock 42.5

Leaf litter 0

Biologic soil crust 2.25

33
Table 5. Vegetation cover and substrate measured at Site 4 (Rapid 5, Right, noncamp pod)—Continued.

Riverward Circle Vegetation Percent Cover

Unidentified annual grass 5.13

Pale evening primrose (Oenothera pallida) 2.15

Dropseed (Sporobolus sp.) 2.13

Rice grass (Oryzopsis hymenoides) 1.60

Russian thistle (Salsola sp.) 0.63

Unidentified forb 0.18

Brome grasses (Bromus sp.) 0.13

Total 11.9

Substrate Percent Cover

Sand 89.5

Rock 10.5

Leaf litter 0

Biologic soil crust 0

Total gap length on upstream/downstream transect (out of 2,000 cm): 1,062 cm

Total gap length on inland/riverward transect (out of 2,000 cm): 1,439 cm

Summary

Total vegetation cover, in percent 14.4

Total sand substrate, in percent 63.7

Total rock substrate, in percent 33.2

Total leaf litter substrate, in percent 2.40

Total biologic crust substrate, in percent 0.75

Total gap length, in percent 62.5

34
Table 6. Vegetation cover and substrate measured at Site 5 (Lower 5, Right, camp pod).

Center Circle Vegetation Percent Cover

Dicoria (Dicoria canescens) 9.00

Russian thistle (Salsola sp.) 4.13

Sand verbena (Abronia elliptica) 3.50

Rice grass (Oryzopsis hymenoides) 2.00

Dropseed (Sporobolus sp.) 0.50

Total 19.1

Substrate Percent Cover

Sand 97.0

Rock 0

Leaf litter 3.00

Biologic soil crust 0

Upstream Circle Vegetation Percent Cover

Tamarisk (Tamarix sp.) 25.0

Brome grasses (Bromus sp.) 20.0

Russian thistle (Salsola sp.) 1.50

Sand verbena (Abronia elliptica) 1.00

Rice grass (Oryzopsis hymenoides) 1.00

Unidentified aster/composite 0.75

Unidentified perennial grass 0.50

Needle-and-thread (Stipa comata) 0.50

Dicoria (Dicoria canescens) 0.10

Total 50.4

Substrate Percent Cover

Sand 76.5

Rock 2.50

Leaf litter 21.0

Biologic soil crust 0

35
Table 6. Vegetation cover and substrate measured at Site 5 (Lower 5, Right, camp pod)—Continued.

Downstream Circle Vegetation Percent Cover

Rice grass (Oryzopsis hymenoides) 1.13

Netleaf hackberry (Celtis laevigata) 1.00

Russian thistle (Salsola sp.) 0.50

Unidentified perennial grass 0.50

Unidentified forb 0.18

Total 3.30

Substrate Percent Cover

Sand 65.0

Rock 35.0

Leaf litter 0

Biologic soil crust 0

Inland Circle Vegetation Percent Cover

Brome grasses (Bromus sp.) 9.00

Netleaf hackberry (Celtis laevigata) 2.75

Dropseed (Sporobolus sp.) 2.50

Wire lettuce (Stephanomeria pauciflora) 1.90

Desert trumpet (Eriogonum inflatum) 1.50

Globemallow (Sphaeralcea sp.) 1.25

Rice grass (Oryzopsis hymenoides) 1.00

Snakeweed (Gutierrezzia sp.) 0.90

Unidentified aster/composite 0.10

Russian thistle (Salsola sp.) 0.10

Sand verbena (Abronia elliptica) 0.10

Total 21.1

Substrate Percent Cover

Sand 78.0

Rock 13.0

Leaf litter 0

Biologic soil crust 9.00

36
Table 6. Vegetation cover and substrate measured at Site 5 (Lower 5, Right, camp pod)—Continued.

Riverward Circle Vegetation Percent Cover

Tamarisk (Tamarix sp.) 15.0

Unidentified forb 1.00

Willow (Salix exigua) 0.50

Total 16.5

Substrate Percent Cover

Sand 99.5

Rock 0

Leaf litter 0.50

Biologic soil crust 0

Total gap length on upstream/downstream transect (out of 4,000 cm): 3,488 cm

Total gap length on inland/riverward transect (out of 4,000 cm): 3,447 cm

Summary

Total vegetation cover, in percent 22.1

Total sand substrate, in percent 83.2

Total rock substrate, in percent 10.1

Total leaf litter substrate, in percent 4.90

Total biologic crust substrate, in percent 1.80

Total gap length, in percent 86.7

37
Table 7. Vegetation cover and substrate measured at Site 6 (Lower 5, Right, noncamp pod).

Center Circle Vegetation Percent Cover

Brome grasses (Bromus sp.) 60.0

Russian thistle (Salsola sp.) 7.00

Unidentified aster/composite 1.00

Unidentified perennial forb 1.00

Needle-and-thread (Stipa comata) 1.00

Total 70.0

Substrate Percent Cover

Sand 23.6

Rock 0.88

Leaf litter 10.5

Biologic soil crust 65.0

Upstream Circle Vegetation Percent Cover

Russian thistle (Salsola sp.) 6.50

Brome grasses (Bromus sp.) 5.50

Unidentified perennial grass 4.50

Dropseed (Sporobolus sp.) 3.50

Unidentified perennial forb 1.70

Unidentified aster/composite 1.00

Sand verbena (Abronia elliptica) 1.00

Total 23.7

Substrate Percent Cover

Sand 87.0

Rock 0

Leaf litter 6.00

Biologic soil crust 7.00

38
Table 7. Vegetation cover and substrate measured at Site 6 (Lower 5, Right, noncamp pod)—Continued.

Downstream Circle Vegetation Percent Cover

Russian thistle (Salsola sp.) 4.50

Spike dropseed (Sporobolus contractus) 3.00

Unidentified aster/composite 2.00

Brome grasses (Bromus sp.) 1.75

Sand verbena (Abronia elliptica) 1.75

Dropseed (Sporobolus sp.) 1.10

Pale evening primrose (Oenothera pallida) 0.75

Dicoria (Dicoria canescens) 0.75

Unidentified perennial grass 0.50

Total 16.1

Substrate Percent Cover

Sand 99.9

Rock 0.10

Leaf litter 0

Biologic soil crust 0

Inland Circle Vegetation Percent Cover

Russian thistle (Salsola sp.) 16.5

Brome grasses (Bromus sp.) 2.50

Dropseed (Sporobolus sp.) 1.00

Unidentified aster/composite 0.50

Total 20.5

Substrate Percent Cover

Sand 20.0

Rock 10.0

Leaf litter 0

Biologic soil crust 70.0

39
Table 7. Vegetation cover and substrate measured at Site 6 (Lower 5, Right, noncamp pod)—Continued.

Riverward Circle Vegetation Percent Cover

Russian thistle (Salsola sp.) 45.0

Brome grasses (Bromus sp.) 10.0

Unidentified aster/composite 2.50

Unidentified perennial grass 2.00

Dropseed (Sporobolus sp.) 1.00

Needle-and-thread (Stipa comata) 1.00

Unidentified forb 0.10

Total 61.6

Substrate Percent Cover

Sand 48.5

Rock 1.50

Leaf litter 5.00

Biologic soil crust 45.0

Total gap length on upstream/downstream transect (out of 4,000 cm): 1,799 cm

Total gap length on inland/riverward transect (out of 4,000 cm): 782 cm

Summary

Total vegetation cover, in percent 38.4

Total sand substrate, in percent 55.8

Total rock substrate, in percent 2.50

Total leaf litter substrate, in percent 4.30

Total biologic crust substrate, in percent 37.4

Total gap length, in percent 32.3

40
Table 8. Vegetation cover and substrate measured at Site 7 (Upper Tilted Park, Left).

Center Circle Vegetation Percent Cover

Rice grass (Oryzopsis hymenoides) 12.5

Inland saltgrass (Distichlis spicata) 3.25

Unidentified aster/composite 1.25

Unidentified aster/composite, dead 1.00

Total 18.0

Substrate Percent Cover

Sand 98.0

Rock 0

Leaf litter 2.00

Biologic soil crust 0

Upstream Circle Vegetation Percent Cover

Sand verbena (Abronia elliptica) 4.25

Tamarisk (Tamarix sp.) 3.00

Rice grass (Oryzopsis hymenoides) 2.25

Unidentified forb 2.06

Brome grasses (Bromus sp.) 1.50

Inland saltgrass (Distichlis spicata) 0.25

Total 13.3

Substrate Percent Cover

Sand 91.3

Rock 0

Leaf litter 8.75

Biologic soil crust 0

41
Table 8. Vegetation cover and substrate measured at Site 7 (Upper Tilted Park, Left)—Continued.

Downstream Circle Vegetation Percent Cover

Tamarisk (Tamarix sp.) 20.0

Inland saltgrass (Distichlis spicata) 11.8

Unidentified forb 3.30

Rice grass (Oryzopsis hymenoides) 0.50

Russian thistle (Salsola sp.) 0.50

Total 36.1

Substrate Percent Cover

Sand 97.3

Rock 0

Leaf litter 2.75

Biologic soil crust 0

Inland Circle Vegetation Percent Cover

Tamarisk (Tamarix sp.) 20.0

Inland saltgrass (Distichlis spicata) 8.00

Brome grasses (Bromus sp.) 5.00

Spike dropseed (Sporobolus contractus) 3.50

Unidentified aster/composite 0.20

Total 36.7

Substrate Percent Cover

Sand 40.0

Rock 0

Leaf litter 60.0

Biologic soil crust 0

42
Table 8. Vegetation cover and substrate measured at Site 7 (Upper Tilted Park, Left)—Continued.

Riverward Circle Vegetation Percent Cover

Willow (Salix exigua) 6.50

Total 6.50

Substrate Percent Cover

Sand 98.8

Rock 0

Leaf litter 1.25

Biologic soil crust 0

Total gap length on upstream/downstream transect (out of 4,000 cm): 3,469 cm

Total gap length on inland/riverward transect (out of 4,000 cm): 2,226 cm

Summary

Total vegetation cover, in percent 22.1

Total sand substrate, in percent 85.1

Total rock substrate, in percent 0

Total leaf litter substrate, in percent 15.0

Total biologic crust substrate, in percent 0

Total gap length, in percent 71.2

43
Table 9. Vegetation cover and substrate measured at Site 8 (Lower Y, Right).

Center Circle Vegetation Percent Cover

Willow (Salix exigua) 10.0

Brome grasses (Bromus sp.) 6.50

Snakeweed (Gutierrezzia sp.) 4.25

Unidentified perennial grass 4.00

Rice grass (Oryzopsis hymenoides) 1.75

Unidentified aster/composite 1.58

Dropseed (Sporobolus sp.) 0.50

Unidentified forb 0.10

Total 26.5

Substrate Percent Cover

Sand 90.3

Rock 1.00

Leaf litter 8.75

Biologic soil crust 0

Upstream Circle Vegetation Percent Cover

Unidentified perennial grass 10.0

Rice grass (Oryzopsis hymenoides) 4.50

Tamarisk (Tamarix sp.) 3.50

Dropseed (Sporobolus sp.) 2.00

Cottonwood (Populus sp.), dead 1.50

Unidentified aster/composite 0.25

Total 21.8

Substrate Percent Cover

Sand 86.5

Rock 0

Leaf litter 13.5

Biologic soil crust 0

44
Table 9. Vegetation cover and substrate measured at Site 8 (Lower Y, Right)—Continued.

Downstream Circle Vegetation Percent Cover

Snakeweed (Gutierrezzia sp.) 5.50

Brome grasses (Bromus sp.) 2.50

Unidentified perennial grass, dead 2.00

Wire lettuce (Stephanomeria pauciflora) 1.75

Unidentified aster/composite 1.00

Willow (Salix exigua) 0.20

Unidentified perennial grass 0.10

Total 13.1

Substrate Percent Cover

Sand 68.5

Rock 30.0

Leaf litter 1.00

Biologic soil crust 0.50

Inland Circle Vegetation Percent Cover

Tamarisk (Tamarix sp.) 15.0

Unidentified perennial grasses 7.50

Sand verbena (Abronia elliptica) 5.50

Saltbush (Atriplex sp.) 4.50

Rice grass (Oryzopsis hymenoides) 2.25

Brome grasses (Bromus sp.) 1.50

Wire lettuce (Stephanomeria pauciflora) 0.70

Total 37.0

Substrate Percent Cover

Sand 65.0

Rock 0

Leaf litter 28.0

Biologic soil crust 7.00

45
Table 9. Vegetation cover and substrate measured at Site 8 (Lower Y, Right)—Continued.

Riverward Circle Vegetation Percent Cover

Unidentified perennial grasses 12.5

Willow (Salix exigua) 5.50

Unidentified aster/composite 0.50

Total 18.5

Substrate Percent Cover

Sand 64.5

Rock 35.0

Leaf litter 0.50

Biologic soil crust 0

Total gap length on upstream/downstream transect (out of 4,000 cm): 2,351 cm

Total gap length on inland/riverward transect (out of 4,000 cm): 1,435 cm

Summary

Total vegetation cover, in percent 23.6

Total sand substrate, in percent 75.0

Total rock substrate, in percent 13.2

Total leaf litter substrate, in percent 10.4

Total biologic crust substrate, in percent 1.50

Total gap length, in percent 47.3

46
Table 10. Vegetation cover and substrate measured at Site 9 (Big Drop Beach, Left).

Center Circle Vegetation Percent Cover

Rice grass (Oryzopsis hymenoides) 6.88

Sand verbena (Abronia elliptica) 6.50

Wire lettuce (Stephanomeria pauciflora) 6.50

Long-leaf brickellbush (Brickellia longifolia) 2.00

Brome grasses (Bromus sp.) 0.50

Russian thistle (Salsola sp.) 0.38

Total 22.8

Substrate Percent Cover

Sand 98.5

Rock 0

Leaf litter 1.50

Biologic soil crust 0

Upstream Circle Vegetation Percent Cover

Rabbitbrush (Chrysothamnus sp.) 9.00

Netleaf hackberry (Celtis laevigata) 5.50

Saltbush (Atriplex sp.) 3.00

Sand verbena (Abronia elliptica) 1.70

Brome grasses (Bromus sp.) 1.50

Dropseed (Sporobolus sp.) 0.75

Total 21.5

Substrate Percent Cover

Sand 64.3

Rock 0.50

Leaf litter 3.00

Biologic soil crust 32.2

47
Table 10. Vegetation cover and substrate measured at Site 9 (Big Drop Beach, Left)—Continued.

Downstream Circle Vegetation Percent Cover

Rice grass (Oryzopsis hymenoides) 3.20

Prince's plume (Stanleya pinnata) 2.00

Wire lettuce (Stephanomeria pauciflora) 1.00

Russian thistle (Salsola sp.) 0.55

Sand verbena (Abronia elliptica) 0.15

Unidentified annual grass 0.10

Total 7.00

Substrate Percent Cover

Sand 92.0

Rock 6.00

Leaf litter 2.00

Biologic soil crust 0

Inland Circle Vegetation Percent Cover

Rabbitbrush (Chrysothamnus sp.) 17.5

Ephedra (Ephedra sp.) 12.5

Prince's plume (Stanleya pinnata) 3.00

Saltbush (Atriplex sp.) 2.50

Rabbitbrush (Chrysothamnus sp.), dead 1.75

Total 37.3

Substrate Percent Cover

Sand 3.00

Rock 6.50

Leaf litter 40.0

Biologic soil crust 50.5

48
Table 10. Vegetation cover and substrate measured at Site 9 (Big Drop Beach, Left)—Continued.

Riverward Circle Vegetation Percent Cover

Long-leaf brickellbush (Brickellia longifolia) 16.5

Wire lettuce (Stephanomeria pauciflora) 4.50

Rice grass (Oryzopsis hymenoides) 3.50

Brome grasses (Bromus sp.) 1.50

Dropseed (Sporobolus sp.) 1.00

Total 27.0

Substrate Percent Cover

Sand 77.5

Rock 15.5

Leaf litter 7.00

Biologic soil crust 0

Total gap length on upstream/downstream transect (out of 2,000 cm): 1,569 cm

Total gap length on inland/riverward transect (out of 2,000 cm): 1,072 cm

Summary

Total vegetation cover, in percent 23.1

Total sand substrate, in percent 67.1

Total rock substrate, in percent 5.70

Total leaf litter substrate, in percent 10.7

Total biologic crust substrate, in percent 16.5

Total gap length, in percent 66.0

49
Table 11. Vegetation cover and substrate measured at Site 10 (Upper 25, Right).

Center Circle Vegetation Percent Cover

Rice grass (Oryzopsis hymenoides) 13.0

Long-leaf brickellbush (Brickellia longifolia) 6.00

Squawbush (Rhus sp.) 5.00

Snakeweed (Gutierrezzia sp.) 3.50

Wire lettuce (Stephanomeria pauciflora) 2.50

Total 30.0

Substrate Percent Cover

Sand 84.8

Rock 14.8

Leaf litter 0.50

Biologic soil crust 0

Upstream Circle Vegetation Percent Cover

Long-leaf brickellbush (Brickellia longifolia) 9.00

Netleaf hackberry (Celtis laevigata) 5.00

Rice grass (Oryzopsis hymenoides) 3.50

Snakeweed (Gutierrezzia sp.) 2.75

Needle-and-thread (Stipa comata) 2.00

Russian thistle (Salsola sp.) 0.50

Total 22.8

Substrate Percent Cover

Sand 59.9

Rock 40.0

Leaf litter 0.10

Biologic soil crust 0

50
Table 11. Vegetation cover and substrate measured at Site 10 (Upper 25, Right)—Continued.

Downstream Circle Vegetation Percent Cover

Netleaf hackberry (Celtis laevigata) 6.50

Wire lettuce (Stephanomeria pauciflora) 6.00

Unidenfied perennial forb 5.00

Rice grass (Oryzopsis hymenoides) 3.50

Needle-and-thread (Stipa comata) 1.75

Snakeweed (Gutierrezzia sp.) 1.00

Unidentified aster/composite 0.50

Russian thistle (Salsola sp.) 0.25

Total 24.5

Substrate Percent Cover

Sand 82.4

Rock 11.5

Leaf litter 6.00

Biologic soil crust 0.10

Inland Circle Vegetation Percent Cover

Squawbush (Rhus sp.) 18.0

Needle-and-thread (Stipa comata) 13.5

Brome grasses (Bromus sp.) 1.00

Snakeweed (Gutierrezzia sp.) 0.75

Wire lettuce (Stephanomeria pauciflora) 0.40

Rice grass (Oryzopsis hymenoides) 0.30

Total 34.0

Substrate Percent Cover

Sand 50.0

Rock 25.0

Leaf litter 10.0

Biologic soil crust 15.0

51
Table 11. Vegetation cover and substrate measured at Site 10 (Upper 25, Right)—Continued.

Riverward Circle Vegetation Percent Cover

Rice grass (Oryzopsis hymenoides) 1.00

Total 1.00

Substrate Percent Cover

Sand 51.5

Rock 45.0

Leaf litter 3.50

Biologic soil crust 0

Total gap length on upstream/downstream transect (out of 2,000 cm): 1,678 cm

Total gap length on inland/riverward transect (out of 2,000 cm): 1,072 cm

Summary

Total vegetation cover, in percent 22.4

Total sand substrate, in percent 65.7

Total rock substrate, in percent 27.3

Total leaf litter substrate, in percent 4.02

Total biologic crust substrate, in percent 3.02

Total gap length, in percent 68.8

52
Table 12. Vegetation cover and substrate measured at Site 11 (Lower 25, Right).

Center Circle Vegetation Percent Cover

Russian thistle (Salsola sp.) 6.00

Sand verbena (Abronia elliptica) 4.50

Unidentified perennial forb 4.00

Rice grass (Oryzopsis hymenoides) 3.50

Unidentified perennial forb, dead 3.50

Brome grasses (Bromus sp.) 1.50

Needle-and-thread (Stipa comata) 1.50

Pale evening primrose (Oenothera pallida) 0.75

Total 25.3

Substrate Percent Cover

Sand 92.9

Rock 0

Leaf litter 7.00

Biologic soil crust 0.10

Upstream Circle Vegetation Percent Cover

Needle-and-thread (Stipa comata) 7.50

Unidentified perennial forb 6.75

Unidentified shrub, dead 3.00

Unidentified legume 1.25

Wire lettuce (Stephanomeria pauciflora) 1.00

Russian thistle (Salsola sp.) 0.75

Rice grass (Oryzopsis hymenoides) 0.50

Unidentified annual grass 0.50

Dropseed (Sporobolus sp.) 0.50

Sand verbena (Abronia elliptica) 0.25

Unidentified aster/composite 0.10

Total 14.6

Substrate Percent Cover

Sand 83.5

Rock 6.50

Leaf litter 0

Biologic soil crust 10.0

53
Table 12. Vegetation cover and substrate measured at Site 11 (Lower 25, Right)—Continued.

Downstream Circle Vegetation Percent Cover

Unidentified forbs 16.3

Unidentified perennial forb, dead 7.00

Russian thistle (Salsola sp.) 3.50

Rice grass (Oryzopsis hymenoides) 1.00

Sand verbena (Abronia elliptica) 0.50

Dropseed (Sporobolus sp.) 0.50

Globemallow (Sphaeralcea sp.) 0.25

Total 29.0

Substrate Percent Cover

Sand 92.0

Rock 0

Leaf litter 5.50

Biologic soil crust 2.50

Inland Circle Vegetation Percent Cover

Ephedra (Ephedra sp.) 55.0

Rice grass (Oryzopsis hymenoides) 1.25

Brome grasses (Bromus sp.) 0.25

Total 56.5

Substrate Percent Cover

Sand 10.0

Rock 20.0

Leaf litter 50.0

Biologic soil crust 20.0

54
Table 12. Vegetation cover and substrate measured at Site 11 (Lower 25, Right)—Continued.

Riverward Circle Vegetation Percent Cover

Rice grass (Oryzopsis hymenoides) 3.00

Unidentified perennial grass 2.50

Wire lettuce (Stephanomeria pauciflora) 1.75

Brome grasses (Bromus sp.) 1.50

Russian thistle (Salsola sp.) 1.00

Ephedra (Ephedra sp.) 0.50

Globemallow (Sphaeralcea sp.) 0.50

Total 10.8

Substrate Percent Cover

Sand 37.5

Rock 55.0

Leaf litter 3.00

Biologic soil crust 4.50

Total gap length on upstream/downstream transect (out of 4,000 cm): 2,618 cm

Total gap length on inland/riverward transect (out of 4,000 cm): 2,829 cm

 

Summary

Total vegetation cover, in percent 28.7

Total sand substrate, in percent 63.2

Total rock substrate, in percent 16.3

Total leaf litter substrate, in percent 13.1

Total biologic crust substrate, in percent 7.42

Total gap length, in percent 68.1

55
Table 13. Vegetation cover and substrate measured at Site 12 (Ten Cent Camp, Left).

Center Circle Vegetation Percent Cover

Netleaf hackberry (Celtis laevigata) 8.00

Unidentified perennial forb 7.50

Wire lettuce (Stephanomeria pauciflora) 3.50

Apache plume (Fallugia paradoxa) 2.50

Rice grass (Oryzopsis hymenoides) 1.50

Unidentified perennial grass 0.50

Total 23.5

Substrate Percent Cover

Sand 51.5

Rock 46.0

Leaf litter 2.50

Biologic soil crust 0

Upstream Circle Vegetation Percent Cover

Unidentified perennial forb 10.0

Apache plume (Fallugia paradoxa) 6.00

Unidentified legume 1.00

Unidentified aster/composite 0.75

Rice grass (Oryzopsis hymenoides) 0.75

Netleaf hackberry (Celtis laevigata) 0.50

Wire lettuce (Stephanomeria pauciflora) 0.25

Brome grasses (Bromus sp.) 0.25

Needle-and-thread (Stipa comata) 0.20

Total 19.7

Substrate Percent Cover

Sand 84.0

Rock 15.0

Leaf litter 1.00

Biologic soil crust 0

56
Table 13. Vegetation cover and substrate measured at Site 12 (Ten Cent Camp, Left)—Continued.

Downstream Circle Vegetation Percent Cover

Apache plume (Fallugia paradoxa) 8.50

Unidentified shrub 7.00

Rice grass (Oryzopsis hymenoides) 5.00

Wire lettuce (Stephanomeria pauciflora) 5.00

Unidentified legume 4.00

Netleaf hackberry (Celtis laevigata) 2.75

Total 32.3

Substrate Percent Cover

Sand 89.3

Rock 10.0

Leaf litter 0.75

Biologic soil crust 0

Inland Circle Vegetation Percent Cover

Apache plume (Fallugia paradoxa) 35.0

Netleaf hackberry (Celtis laevigata) 1.50

Brome grasses (Bromus sp.) 0.50

Unidentified aster/composite 0.10

Total 37.1

Substrate Percent Cover

Sand 71.0

Rock 4.00

Leaf litter 5.00

Biologic soil crust 20.0

57
Table 13. Vegetation cover and substrate measured at Site 12 (Ten Cent Camp, Left)—Continued.

Riverward Circle Vegetation Percent Cover

Netleaf hackberry (Celtis laevigata) 30.0

Wire lettuce (Stephanomeria pauciflora) 5.50

Rice grass (Oryzopsis hymenoides) 1.00

Brome grasses (Bromus sp.) 1.00

Unidentified perennial grass 0.50

Total 38.0

Substrate Percent Cover

Sand 54.0

Rock 45.0

Leaf litter 1.00

Biologic soil crust 0

Total gap length on upstream/downstream transect (out of 2,000 cm): 1,606 cm

Total gap length on inland/riverward transect (out of 2,000 cm): 1,426 cm

 

Summary

Total vegetation cover, in percent 30.1

Total sand substrate, in percent 70.0

Total rock substrate, in percent 24.0

Total leaf litter substrate, in percent 2.05

Total biologic crust substrate, in percent 4.00

Total gap length, in percent 75.8

58
Table 14. Vegetation cover and substrate measured at Site 13 (Lower Ten Cent, Left).

Center Circle Vegetation Percent Cover

Unidentified perennial grass 10.5

Ephedra (Ephedra sp.) 5.50

Needle-and-thread (Stipa comata) 2.00

Russian thistle (Salsola sp.) 1.00

Unidentified forbs 0.70

Sand verbena (Abronia elliptica) 0.50

Rice grass (Oryzopsis hymenoides) 0.50

Brome grasses (Bromus sp.) 0.50

Bindweed heliotrope (Heliotropium convolvulaceum) 0.10

Total 21.3

Substrate Percent Cover

Sand 86.5

Rock 0

Leaf litter 3.50

Biologic soil crust 10.0

Upstream Circle Vegetation Percent Cover

Ephedra (Ephedra sp.) 7.25

Needle-and-thread (Stipa comata) 2.75

Rice grass (Oryzopsis hymenoides) 2.25

Dicoria (Dicoria canescens) 1.50

Spike dropseed (Sporobolus contractus) 0.90

Dropseed (Sporobolus sp.) 0.60

Unidentified perennial grass, dead 0.50

Sand verbena (Abronia elliptica) 0.40

Bindweed heliotrope (Heliotropium convolvulaceum) 0.20

Total 16.4

Substrate Percent Cover

Sand 100

Rock 0

Leaf litter 0

Biologic soil crust 0

59
Table 14. Vegetation cover and substrate measured at Site 13 (Lower Ten Cent, Left)—Continued.

Downstream Circle Vegetation Percent Cover

Ephedra (Ephedra sp.) 9.00

Unidentified perennial grasses 8.50

Wire lettuce (Stephanomeria pauciflora) 6.50

Needle-and-thread (Stipa comata) 4.25

Russian thistle (Salsola sp.) 0.75

Sand verbena (Abronia elliptica) 0.50

Unidentified annual grass 0.25

Brome grasses (Bromus sp.) 0.13

Bindweed heliotrope (Heliotropium convolvulaceum) 0.10

Total 30.0

Substrate Percent Cover

Sand 93.5

Rock 0

Leaf litter 5.50

Biologic soil crust 1.00

Inland Circle Vegetation Percent Cover

Ephedra (Ephedra sp.) 10.0

Unidentified perennial grass 7.00

Unidentified annual grass 4.00

Unidentified perennial grass, dead 3.25

Russian thistle (Salsola sp.) 2.88

Needle-and-thread (Stipa comata) 2.50

Wire lettuce (Stephanomeria pauciflora) 2.50

Rice grass (Oryzopsis hymenoides) 1.75

Sand verbena (Abronia elliptica) 0.50

Unidentified forb 0.20

Brome grasses (Bromus sp.) 0.10

Total 34.7

Substrate Percent Cover

Sand 92.5

Rock 0

Leaf litter 4.50

Biologic soil crust 3.00

60
Table 14. Vegetation cover and substrate measured at Site 13 (Lower Ten Cent, Left)—Continued.

Riverward Circle Vegetation Percent Cover

Rice grass (Oryzopsis hymenoides) 5.50

Russian thistle (Salsola sp.) 3.50

Sand verbena (Abronia elliptica) 1.50

Needle-and-thread (Stipa comata) 1.00

Unidentified perennial grass 1.00

Bindweed heliotrope (Heliotropium convolvulaceum) 0.38

Brome grasses (Bromus sp.) 0.10

Unidentified legume 0.10

Total 13.1

Substrate Percent Cover

Sand 98.9

Rock 0.10

Leaf litter 1.00

Biologic soil crust 0

Total gap length on upstream/downstream transect (out of 2,000 cm): 1,547 cm

Total gap length on inland/riverward transect (out of 2,000 cm): 1,671 cm

 

Summary

Total vegetation cover, in percent 23.1

Total sand substrate, in percent 94.3

Total rock substrate, in percent 0

Total leaf litter substrate, in percent 2.90

Total biologic crust substrate, in percent 2.80

Total gap length, in percent 80.5

61