Geomorphology 31 Ž1999. 313–323
Effectiveness of sediment control structures relative to spatial
patterns of upland soil loss in an arid watershed, Wyoming
Richard A. Marston a,) , Lawrence S. Dolan b
a
School of Geology, Oklahoma State UniÕersity, Stillwater, OK 74078-3031, USA
b
Montana Department of Natural Resources, Helena, MT 59620-2301, USA
Received 6 December 1996; received in revised form 1 May 1997; accepted 15 May 1997
Abstract
Rainfall simulation experiments have been used to identify the variables that control rates of gross soil erosion in upland
areas of the Fifteenmile Creek drainage in Wyoming. Rates of gross soil erosion were found to be most closely related to
slope gradient, vegetation density, and soil texture. These variables were mapped for the drainage and digitized files of these
maps were combined in a geographic information system to depict the spatial pattern of soil mobilization. Gross soil erosion
in badland areas was found to be extreme when compared to the remainder of the drainage. Neither structural nor
non-structural sediment control strategies are well-suited to these badland areas. Engineering structures to control sediment
export had been constructed in poorly chosen locations at extreme and unnecessary expense to taxpayers. q 1999 Elsevier
Science B.V. All rights reserved.
Keywords: soil erosion; GIS; badlands; arid environments
1. Introduction
Fifteenmile Creek contributes less than 1% of the
mean annual flow to the Bighorn River but 75% of
the mean annual suspended sediment load, rendering
the Fifteenmile Creek drainage as one of the most
prolific producers of sediment in the state of
Wyoming ŽFig. 1; Ostresh et al., 1990.. Fifteenmile
Creek was identified as a ‘‘red flag’’ drainage in
need of an aggressive sediment control program by
the USDI Bureau of Land Management in the 1960s
ŽCooper, 1979.. At a cost of US$2 million to taxpay)
Corresponding author. Tel.: q1-307-744-9247; fax: q1-307744-7841.
E-mail address: marstor@uwyo.edu ŽR.A. Marston..
ers over a 10-year period, the following structural
controls were implemented: 34 sediment detention
dams, 110 reservoirs, and 21 spreader dikes. In
addition, 2486 ha were contour-furrowed, grazing
allotments were readjudicated, and 14,000 animalmouths of grazing pressure were eliminated. Yochem
and Rosenlieb Ž1978. evaluated suspended sediment
concentrations in response to these measures using
20 years of streamflow and sediment data from a
gauging station on Fifteenmile Creek near its confluence with the Bighorn River. They concluded that a
25% reduction in sediment concentrations could be
directly attributed to the watershed improvements.
However, recent inspection of the structures revealed
that many have failed from lack of maintenance,
reintroducing stored sediment back into the channel
0169-555Xr99r$ - see front matter q 1999 Elsevier Science B.V. All rights reserved.
PII: S 0 1 6 9 - 5 5 5 X Ž 9 9 . 0 0 0 8 9 - 6
314
R.A. Marston, L.S. Dolan r Geomorphology 31 (1999) 313–323
Fig. 1. Location of the Fifteenmile Creek drainage within the Bighorn Basin, State of Wyoming. View is oblique from south to north. For
scale, the dimensions of Wyoming are 586 km east–west by 447 km north–south.
ŽFig. 2.. More importantly, the poor performance of
the Fifteenmile Creek sediment control program can
be blamed on the failure to systematically identify
nonpoint sources of sediment for optimal placement
of sediment control structures. The objectives of this
paper are to: Ž1. determine the land surface factors
that influence upland sediment production, and Ž2.
identify those portions of the drainage that contribute
the majority of upland soil mobilization. This paper
does not examine solute export, sediment delivery
from upland areas, or sources of sediment production
from the streamside riparian zone.
Fifteenmile Creek is a 1350 km2 drainage in the
Bighorn Basin of north–central Wyoming ŽFig. 1..
The basin has a median elevation of 1500 m and is
situated in the rainshadow of the Absaroka Range to
the west. The basin is a cold desert environment
ŽKoppen
BWK climate type. with a mean annual
¨
temperature of 78C. and mean annual precipitation of
200 mm of which approximately 10% falls as snow
and 40% falls as summer rain ŽMartner, 1987.. Locally intense summer thunderstorms occur throughout the drainage, commonly generating a large portion of the mean annual precipitation. Vegetation is
occasionally absent, but where present it is dominated by shrubs, low grasses and forbs and cacti.
Sagebrush Ž Artemesia spp.. and saltbush Ž Atriplex
spp.. are the predominant shrub species found in the
upland areas. Blue grama grass Ž Bouteloua gracilis .,
a sod-forming grass, and rhizomatous wheatgrass
Ž Agropyron spp.. are the prevailing grasses and
prickly pear Ž Opuntia polycantha. is the principal
cactus. The drainage is underlain by the Willwood
Formation, Eocene claystones and sandstones which
have been eroded into badlands topography ŽFig. 3..
Soils range from clayey to sandy as a function of
parent materials such as shale, mixed alluvium, siltstones and sandstones. In addition, the soils are
alkaline and classified as aridisols ŽKnox et al.,
1979.. Drainages with these characteristics of cli-
R.A. Marston, L.S. Dolan r Geomorphology 31 (1999) 313–323
315
Fig. 2. One of over two dozen sediment detention dams in the Fifteenmile Creek drainage that had been filled then breached since
construction in the 1960s. Over 1 million m3 of sediment had been evacuated following the breach of this particular dam. Photo by R.A.
Marston.
mate, soils, topography and vegetation are particularly susceptible to erosion by rainsplash, piping and
overland flow ŽMorris, 1986..
Grazing of livestock has been the dominant land
use in the drainage for over 100 years and livestock
are often cited by environmentalists and scientists as
the culprit for the extreme rates of sediment production from Fifteenmile Creek. The degree to which
grazing has altered the prehistoric plant communities
of the Bighorn Basin has not been well-established.
Dorn Ž1976. used repeat photography and historical
journals to conclude that vegetation density and
composition have been essentially unchanged. Others
have reviewed the literature which demonstrates that
livestock in similar geographic settings eliminate
native grasses in favor of shrubs and bunch grasses,
accelerating upland runoff and erosion Že.g., Lusby,
1970; Satterlund, 1972; Cooke and Reeves, 1976;
Branson et al., 1981; Graf, 1985.. Whether the ex-
treme suspended sediment loads can be attributed to
grazing or to background production is an important
question to resolve for the Fifteenmile Creek drainage
because of the implications for sediment control
strategies.
2. Methods
Because of the large size of the Fifteenmile Creek
drainage, field studies focused on the Middle Fork of
Fifteenmile Creek, with an area of 109 km2 . All
terrain types are represented in the Middle Fork
drainage. To establish a stratified sample of sites for
field studies, the Middle Fork drainage was divided
into landscape units using a computer-generated
overlay of maps of slope gradient class, vegetation
communities, and soil type. Slope gradient class was
determined by the authors from 1:24,000 scale topo-
316
R.A. Marston, L.S. Dolan r Geomorphology 31 (1999) 313–323
Fig. 3. Badlands topography developed in the Willwood Formation. Photo by R.A. Marston.
graphic maps using the contour spacing method
ŽMarsh, 1991.; six slope classes were mapped. Vegetation communities Žclasses by dominant species and
cover. and soil type Žclasses by dominant texture.
were determined using unpublished range site class
maps of the USDI Bureau of Land Management
ŽKnox et al., 1979; Iiams, 1983.. The maps of slope
class, vegetation, and soil texture were digitized with
vector-based ArcInfo software. IDRISI software was
also used to convert the vector-based files into
raster-based files with a cell size of 100 m by 100 m.
A total of 37 study sites were selected in a randomstratified process to represent the range of landscape
units identified in the overlay process.
A rainfall simulator was constructed to conduct
runoff and soil loss experiments at each of the 37
sites ŽFig. 4.. Logistical constraints of remote access,
steep slopes, frequent winds, and lack of turbid-free
water dictated the need for a simulator that was
portable, easy to operate, durable and with a low rate
of water consumption. Therefore, a drop-forming
rainfall simulator design was chosen that is similar in
structure to the Tahoe Basin simulator developed by
Munn and Huntington Ž1976.. The frame for the
rainfall simulator was constructed of lightweight aluminum plate and square tubing. By extending the
upper portion of the frame andror by raising the legs
of the frame, the height of drop fall can be adjusted
from 1.8 m to 2.6 m. The adjustable legs, constructed of steel thread rod, are also used for leveling
the simulator on slopes. Plywood sides were installed
on the frame to shield the falling drops during times
of light to moderate winds. However, a small area
near the top of the simulator was left unshielded to
allow some turbulence to enter and randomize the
drop distribution pattern. Following the advice of
Moeyersons Ž1983., a gutter trough near the base of
the structure captured any drops falling outside the
0.61 m by 0.61 m plot area. A sheet metal border
was used to define the plot perimeter. At the downslope end of the plot, a funnel trough was placed to
direct runoff and sediment into sample containers
R.A. Marston, L.S. Dolan r Geomorphology 31 (1999) 313–323
317
Fig. 4. Rainfall simulator in this study with plywood windshields installed. Photo by R.A. Marston.
ŽFig. 5.. A sheet of galvanized metal was also used
to cover the plot while setting up the experiment.
Our simulator utilizes a Plexiglas water chamber
designed after the one by Chow and Harbough
Ž1965.. The dimensions of the chamber, and of the
plot below, are 0.61 m by 0.61 m and embedded in
the chamber are 576 polyethylene tubing tips with a
0.58 mm inside diameter and 0.97 mm outside diam-
318
R.A. Marston, L.S. Dolan r Geomorphology 31 (1999) 313–323
Fig. 5. Trough used to collect runoff and sediment from 0.6 m = 0.61 m plot at the base of rainfall simulator. Photo by R.A. Marston.
eter. The tubes produce drops with a diameter of 3.2
mm. The rate of water entering the chamber from a
25-l reservoir, located above the drop-forming chamber, and the resulting rate of drop formation are
controlled by a flow meter.
Our simulator produced 3.2 mm drops which fell
from a constant height of 2.3 m. The maximum
velocity of these drops was 5.7 m sy1 ŽEpema and
Riezebos, 1983.. A storm intensity of 760 mm hy1
for a 1-h duration storm was used. This design
storm, held constant through the study Žso as to
isolate differences in terrain controls on runoff and
soil loss., produced a total kinetic energy for each
plot of 456 J, equivalent to a natural 1-h duration
storm of 47 mm. This event is approximately the
50-yearr1-h event for the nearest weather station at
Worland, but it is an event that occurs nearly every
summer at some point in the drainage.
Replicate experiments were conducted at each site
for a total of 74 experiments. During each 1-h experiment, water-sediment samples were collected at 5
min, 15 min, 35 min and 55 min in order to observe
time-dependent changes. Analyses of the water-sediment samples was performed in the Soils Laboratory
of the Department of Geography and Recreation at
the University of Wyoming. Samples were analyzed
for volume Žml. by weight and sediment concentrations Žmg ly1 . by evaporating the water and determining the weight of sediment in the sample. Solutes
were not measured. The total runoff and sediment for
the 1-h experiment was calculated by integrating the
curves of runoff vs. time and soil loss vs. time.
The following site variables were measured:
1. Vegetation density: using the point-intercept
method on photographs of the plot ŽMuellerDombois and Ellenberg, 1974.,
2. Litter density: as above,
3. Slope gradient: using a slope pantometer,
4. Surface soil texture Ž0 cm to 4 cm.: sample
acquired adjacent to the plot and transported to
the soils lab for analysis with a hydrometer.
R.A. Marston, L.S. Dolan r Geomorphology 31 (1999) 313–323
A quantitative index of soil texture was derived
by taking a weighted average of percentage sand Ž0.5
mm–2 mm., coarse silt Ž0.005 mm–0.5 mm., fine
silt Ž0.002 mm–0.005 mm., and clay Ž- 0.002 mm..
An ordinal scale was then used to classify the soil on
a scale of 1 to 4, with 1 being sand and 4 being clay.
Stepwise multiple regression was used to develop
separate estimates of runoff Žml miny1 . and soil loss
Žg miny1 . using the four variables listed above.
3. Results
The range of values found for site variables and
experimental data is presented in Table 1. The rate of
soil loss varied during the 1-h experiment, usually
increasing up to 15 min, then reaching a steady state
ŽFig. 6.. By comparing two sites where all variables
are similar except one, the control of that variable on
soil loss can be discerned. Rates of soil loss were
consistently higher on slopes of steep gradient ŽFig.
6a.. Litter and vegetation density also exerted a
strong control ŽFig. 6b.; these two variables are
intercorrelated. On the one site where litter and
vegetation density were both 100%, the rate of soil
loss declined during the experiment ŽFig. 6c.. This is
attributed to the decline in splash from the downslope end of the plot once the soils had been wetted.
Fine silts were eroded earlier and at a greater rate
than sands ŽFig. 6c..
Stepwise multiple regression yielded the following equation:
Log E s 1.90 q Ž 0.034 . S y Ž 0.00916 . V
q Ž 0.191 . T
Ž 1.
where the variables are as defined in Table 1. The
variables are shown in the order they entered Eq. 1.
319
Because rainfall energy was held constant, but experiments were conducted in a field setting, Eq. 1
differs in forms from many splash transport models
Že.g., Poessen, 1985; Morris, 1986. in that it focuses
on factors of erodability. Generally, rates of soil loss
were highest on steep slopes, with fine-textured soils,
and low vegetation–litter cover, a combination of
site variables which leads to the formation of badlands. The equation is significant at the p - 0.001
level with a r 2 of 0.72. Slope gradient alone explains 62% of the variance in soil loss. Soil loss was
highest in fine silts and clays, contrary to the findings of Poessen Ž1981. who found the highest detachability in fine very well-sorted sands. We suspect
that soil erodability is controlled by several site
characteristics which are important in the Fifteenmile
Creek drainage but which have rarely been noted in
previous studies. For instance, soils of the Bighorn
Basin commonly have indurated calcic horizons close
to the surface, limiting percolation. Salts in surface
soils at concentrations less than 3% were found to
disaggregate fine soils. Second, soil surface crusting
was observed on many plots, a feature which enhances runoff but also counters erosion by increasing
resistance of the soil surface ŽBryan and De Ploey,
1983; Poessen, 1987.. Third, small soil mounds form
around the base of bunch grasses and cacti, concentrating surface runoff from sheetwash into rill-forming flows. Rock fragments also imparted the same
effect in some experimental runs, an effect described
by Poessen Ž1990.. Therefore, microroughness plays
a role in enhancing soil loss which may be more
important than the role of soil factors which affect
infiltration ŽImenson, 1983.. Because of these factors
and the small plot size of our simulator, use of the
Modified Soil Loss Equation ŽMulkey, 1980. was
Table 1
Range of values for site variables and experimental data
Variable
Vegetation density, V Ž%.
Litter density, L Ž%.
Slope gradient, S Ž%.
Soil texture index, T Ž1 s sand, 2 s
coarse silt, 3 s fine silt, 4 s clay.
Runoff Ž1 hy1 .
Soil loss Žg hy1 .
Mean
Standard
deviation
Maximum
49
31
9.5
2.3
25
27
9.4
0.5
100
100
34
3.6
10.0
377
7.0
608
24.4
2860
Minimum
0
0
1
1.5
0
2
320
R.A. Marston, L.S. Dolan r Geomorphology 31 (1999) 313–323
Fig. 6. Effects of slope gradient Ža., vegetationrlitter density Žb., and soil texture Žc. on rates of soil loss during the 1-h experiment.
found to be of no utility in evaluating spatial patterns
or rates of soil loss in this study.
The variables in Eq. 1 had been digitized in raster
format, so it was possible to combine them in their
proper mathematical relation using IDRISI software.
Results were displayed using a 3-D algorithm developed for IDRISI output by Dr. Larry Ostresh of the
University of Wyoming Department of Geography
and Recreation ŽFig. 7.. In this manner, the spatial
pattern of estimated soil loss can be displayed, as
tried previously by Vold et al. Ž1985. in British
Columbia. In some areas, rates of soil loss were
calculated for regions with slope gradients greater
than could be sampled with our rainfall simulator.
From this figure, it is evident that rates of soil loss
vary significantly within the drainage as a function
of slope gradient, vegetation cover, and soil texture.
The badlands in the south–central portion of the
drainage, 8.5% of the drainage by area, contributed
62% of the total soil loss. In contrast, the low relief,
better vegetated lowlands in the eastern portion of
the drainage, 30% of the drainage by area, con-
R.A. Marston, L.S. Dolan r Geomorphology 31 (1999) 313–323
321
Fig. 7. Computer-assisted maps of slope gradient ŽA., vegetation density ŽB., soil texture ŽC., and soil loss ŽD. for the Middle Fork
Fifteenmile Creek drainage. The creek flows from west to east, left to right, across the maps.
tributed only 5.5% of the total soil loss. The remainder of the drainage contributes sediment in quantities
roughly proportional to area. The total gross upland
erosion for the 50-yearr1-h storm is 202,000 tonnes.
4. Discussion and conclusions
A portable rainfall simulator has been used in the
field to identify the relative importance of land sur-
322
R.A. Marston, L.S. Dolan r Geomorphology 31 (1999) 313–323
face variables controlling upland rates of gross soil
erosion. The most important variables controlling
gross soil erosion were slope gradient, vegetation
density, and soil texture. These results are consistent
with variables identified by Meeuwig Ž1970. and
Blackburn and Skau Ž1974. who used rainfall simulators to investigate upland sediment production in
semi-arid drainages. Other, more detailed analyses of
soil crusting, dispersible clays, and microroughness
caused by vegetation may add to the ability to
estimate soil loss in future studies in this geographic
setting. The key variables identified in this study are
variables that could be altered by land management
techniques.
A geographic information system and computeraided mapping have been used to identify the spatial
pattern of upland soil mobilization on the scale of
the drainage basin. A GIS can be used to combine
variables with their proper weighting as determined
from multiple regression. Badlands eroded in the
Willwood Formation, 8.5% of the drainage by area,
account for 62% of the gross soil erosion. This result
compares favorably with the study by Campbell
Ž1977. who found that badlands only occupy 2% of
the Red Deer River drainage but contribute 80% of
the total suspended sediment load.
Possible measures for controlling sediment production from Fifteenmile Creek include increasing
vegetation cover andror constructing sediment control structures. Increasing vegetation cover would be
limited to those areas of the drainage where soil and
slope conditions would allow vegetation to recover.
Unfortunately, it is unlikely that vegetation cover
could be improved or even established in the badland
areas which account for the greatest sediment production. Vegetation buffer strips might prove effective between the base of badland areas and ephemeral
channels. Additional structures would be most effective if constructed adjacent to badlands areas; many
of the structures constructed in the 1960s are situated
in areas of low sediment production. Straw bale or
sandbag sediment traps would be more effective than
the low earthen dams which are easily eroded once
filled with sediment. The effective life of sediment
detention dams, reservoirs, and spreader dikes adjacent to badlands is likely to be short without frequent
maintenance. Because of the extreme rates of background erosion occurring in Fifteenmile Creek
drainage, high rates of sediment production should
continue. Downstream users of the water from the
Bighorn River will have to continue to manage for
the negative effects of this suspended sediment, including increased costs for municipal water treatment, damage to fisheries, and reduced storage volume in a downstream reservoir.
Acknowledgements
The authors wish to acknowledge the cooperation
of the USDI Bureau of Land Management, Worland
District. Special appreciation is extended to L. Ostresh for assistance with the computer assisted mapping and analysis with ArcInfo and IDRISI. Thanks
are also extended to T. Wesche, Q. Skinner, and two
anonymous reviewers at the Laboratory for Experimental Geomorphology at the Catholic University of
Leuven for their constructive comments on an earlier
version of this paper. The authors also wish to thank
D. Haire for his assistance in the field. Funding for
this study was provided through the U.S. Geological
Survey Section 104 Annual Allotment Program in a
matching grant from the U.S. Geological Survey
Ž5-33866. and the Wyoming Water Research Center
Ž5-38706..
References
Blackburn, W.H., Skau, C.M., 1974. A mobile infiltrometer for
use on rangeland. Journal of Range Management 27, 476–480.
Branson, F.A., Gifford, G.F., Renard, K.G., Hadley, R.F., 1981.
Rangeland Hydrology. Kendall-Hunt, Dubuque, IA, 340 pp.
Bryan, R.B., De Ploey, J., 1983. Comparability of soil erosion
measurements with different laboratory rainfall simulators. In:
De Ploey, J. ŽEd.., Rainfall Simulation, Runoff, and Soil
Erosion. Catena Supplement 4, pp. 33–55.
Campbell, I.A., 1977. Stream discharge, suspended sediment and
erosion rates in the Red Deer River basin, Alberta, Canada.
International Association of Hydrological Sciences Publication
122, 244–259.
Chow, V.T., Harbough, T.E., 1965. Raindrop production for
laboratory watershed experimentation. Journal of Geophysical
Research 70, 6111–6119.
Cooke, R.U., Reeves, R.W., 1976. Arroyos and Environmental
Change in the American Southwest. Clarendon Press, Oxford,
213 pp.
Cooper, C., 1979. 208 Water Quality Management Plan for the
Bighorn Basin, Wyoming. Regional Planning Office, Basin,
WY.
R.A. Marston, L.S. Dolan r Geomorphology 31 (1999) 313–323
Dorn, R.D., 1976. The Wyoming Landscape, 1805–1878. Mountain West Publishing, Cheyenne, WY, 94 pp.
Epema, G.F., Riezebos, H.T., 1983. Fall velocity of waterdrops at
different heights as a factor influencing erosivity of simulated
rain. In: De Ploey, J. ŽEd.., Rainfall Simulation, Runoff, and
Soil Erosion. Catena Supplement 4, pp. 1–17.
Graf, W.L., 1985. The Colorado River — Instability and Basin
Management. Resource Paper in Geography, 1984r2. Association of American Geographers, Washington, DC, 86 pp.
Iiams, J.E., 1983. Soil Survey of Washakie County, Wyoming.
USDA Soil Conservation Service, Washington, DC, 236 pp.
Imenson, A.C., 1983. Studies of erosion thresholds in semi-arid
areas — field measurements of soil loss and infiltration in
northern Morocco. In: De Ploey, J. ŽEd.., Rainfall Simulation,
Runoff and Soil Erosion. Catena Supplement 4, pp. 79–90.
Knox, E.G., Nielson, E.C., Wells, R.F., 1979. Soil Inventory of
the Grass Creek Area, Wyoming. Soil and Land Use Technology, Columbia, MD.
Lusby, G.C., 1970. Hydrologic and biotic effects of grazing vs.
non-grazing near Grand Junction, Colorado. Journal of Range
Management 23, 256–260.
Marsh, W.M., 1991. Landscape Planning — Environmental Applications. 2nd edn. Addison-Wesley, Reading, PA, 340 pp.
Martner, B.E., 1987. Wyoming Climate Atlas. University of Nebraska Press, Lincoln, 432 pp.
Meeuwig, R.O., 1970. Infiltration and soil erosion as influenced
by vegetation and soil in northern Utah. Journal of Range
Management 23, 185–188.
Moeyersons, J., 1983. Measurements of splash-saltation fluxes
under oblique rain. In: De Ploey, J. ŽEd.., Rainfall Simulation,
Runoff, and Soil Erosion. Catena Supplement 4, pp. 19–31.
Morris, S.E., 1986. The significance of rainsplash in the surficial
debris cascade of the Colorado Front Range Foothills. Earth
Surface Processes and Landforms 11, 11–22.
323
Mueller-Dombois, D., Ellenberg, H., 1974. Aims and Methods of
Vegetation Ecology. Wiley, New York, 547 pp.
Mulkey, L.A., 1980. An Approach to Water Resources Evaluation
of Nonpoint Silvicultural Sources: A Procedural Handbook.
U.S. Environmental Protection Agency, Athens, GA.
Munn, J.R., Huntington, G.L., 1976. A portable rainfall simulator
for erodability and infiltration measurements on rugged terrain. Soil Science Society of America Journal 40, 622–624.
Ostresh, L.O., Marston, R.A., Hudson, W.A. ŽEds.., 1990.
Wyoming Water Atlas. Wyoming Water Development Commission and University of Wyoming, Cheyenne and Laramie,
WY, 124 pp.
Poessen, J., 1981. Rainwash experiments on the erodability of
loose sediments. Earth Surface Processes and Landforms 6,
285–307.
Poessen, J., 1985. An improved splash transport model. Z. Geomorphol. 29 Ž2., 193–211.
Poessen, J., 1987. The role of slope angle in surface seal formation. In: Gardiner, V. ŽEd.., International Geomorphology
1986 — Part II. Wiley, New York, pp. 437–448.
Poessen, J.W.A., 1990. Conditions for the evacuation of rock
fragments from cultivated upland areas during rainstorms. In:
Erosion, Transport and Deposition Processes. Proceedings of
the Jerusalem Workshop, March–April 1987. pp. 145–160,
IAHS Publ. No. 189.
Satterlund, D.R., 1972. Wildland Watershed Management. Wiley,
New York, 370 pp.
Vold, T., Sondheim, M.W., Nagpal, N.K., 1985. Computer assisted mapping of soil erosion potential. Canadian Journal of
Soil Science 65, 411–418.
Yochem, R., Rosenlieb, G., 1978. Evaluation of the discharge and
suspended sediment load of Fifteenmile Creek, 1952–1972.
Unpublished technical report, USDI Bureau of Land Management, Worland District, Worland, WY, 15 pp.