DOWNSTREAM EFFECTS OF URBANIZATION
ON STILLWATER CREEK, OKLAHOMA
Ranbir S. Kang
Department of Geography
Western Illinois University
Tillman Hall 312
Macomb, Illinois 61455
Daniel E. Storm
Department of Biosystems and Agricultural Engineering
Oklahoma State University
Stillwater, Oklahoma 74075
Richard A. Marston
Department of Geography
Kansas State University
Manhattan, Kansas 66506-2904
Abstract: Geomorphic effects of urbanization vary according to local conditions and
with different ecoregions. This project evaluates the effects of urbanization on Stillwater
Creek, located in central Oklahoma. The upper section of this basin is predominantly
rural, while the downstream section is experiencing urban expansion. It was hypothesized
that the channel morphology of the lower section would differ significantly from that of the
upper section due to the location of the confluence of Boomer Creek, which brings urban
runoff from the city of Stillwater. Statistical analysis of downstream trends revealed no
significant change in the majority of response variables between upstream and downstream sections. However, local conditions (i.e,. riparian trees, cohesive bank materials,
occasional woody debris jams, and entrenched nature) in this basin counter the possible
effects of urbanization on channel morphology. Increasing urbanization was expected to
reduce the sources of woody debris to stream channel and affect channel morphology.
However, Stillwater Creek had thick riparian corridors dominated by trees, which helped
protect stream banks. A downstream parabolic channel cross-sectional shape also helped
explain why this stream channel did not change radically due to urbanization. [Key words:
urbanization, channel morphology, fluvial geomorphology.]
INTRODUCTION
Urbanization has transformed fluvial landscapes in different parts of the world
(Wolman, 1967; Leopold, 1968; Arnold and Gibbons, 1996; Booth and Jackson,
1997; Chin, 2006; Urban et al., 2006; Keen-Zebert, 2007; O’Driscoll et al., 2009).
The expansion of impervious surfaces, a commonly used measure of urbanization,
reduces the infiltration capacity of land and leads to higher runoff compared to
areas not affected by urbanization (Douglas, 1974; May et al., 2002; Li and Wang,
2009). Because water runs faster over impervious surfaces, construction reduces the
186
Physical Geography, 2010, 31, 2, pp. 186–201. DOI: 10.2747/0272-3646.31.2.186
Copyright © 2010 by Bellwether Publishing, Ltd. All rights reserved.
DOWNSTREAM EFFECTS OF URBANIZATION
187
Fig. 1. Study area in the Central Redbed Geomorphic Province of Oklahoma (produced from data
provided by the U.S. Geological Survey and the U.S. Environmental Protection Agency).
lag time of surface runoff and increases debris production as well as flood peaks;
this affects channel morphology in different ways, including alterations in channel
cross-sections, types of bed materials, types of channel units, organic debris, and
riparian vegetation (Orme and Bailey, 1971; Morisawa and Laflure, 1979; Nanson,
1981; Booth, 1990, 1991; Johnson, 2001; Jeje and Ikeazota, 2002; May et al.,
2002; Avolio, 2003; Brierley and Fryirs, 2005; Gurnell et al., 2007). Charbonneau
and Resh (1992) noticed that impacts of urbanization lead to enhanced downcutting, stream bank erosion, and modification of the natural pool-riffle sequence.
Such effects of urbanization, however, vary locally with the degree of imperviousness (urbanization) and are determined by basin and adjacent riparian conditions
(Kang and Marston, 2006; Marston, 2006).
The effects of urbanization on channel morphology are not well understood
(Hammer, 1972; Morisawa and Laflure, 1979; Booth, 1990, 1991; Arnold and
Gibbons, 1996; Booth and Jackson, 1997; Trimble, 1997; Chin and Gregory, 2001;
Chin, 2006; Kang and Marston, 2006). Such a lack of understanding is especially
evident in the Central Redbed Plains geomorphic province of Oklahoma. This
paper, part of a larger project (Kang and Marston, 2006) presents a detailed investigation of Stillwater Creek, located in the Central Redbed Plains geomorphic province, which is transforming from a rural to an urban basin with extensive
impervious growth in the downstream section (Fig. 1). It also evaluates whether the
channel response to urbanization conforms to that found in similar studies conducted in other regions. Therefore, it was anticipated that expansion of impervious
surfaces in the lower section of Stillwater Creek would change the channel
188
KANG ET AL.
Fig. 2. Aerial photograph shows Stillwater Creek flowing through the urbanizing areas of Stillwater,
Oklahoma (MRLC Consortium, 2001).
morphology of downstream reaches, as compared to the upstream section (Gregory
and Park, 1976; Paul and Meyer, 2001).
The confluence of Boomer Creek, a tributary of Stillwater Creek, was used to
divide this river into two sections. The upper section is rural, whereas the lower section is urban and includes the City of Stillwater (Fig. 2). The objective of this
research was to identify any differences in channel morphology of the downstream
section as compared to upstream. If there was a significant difference between the
two sections, could this difference be explained by urbanization? Finally, what factors other than urbanization might explain observed changes in Stillwater Creek?
Six variables (channel width, mean depth, width-depth ratio, bankfull area, sinuosity, and gradient) were compared between the two sections. It was hypothesized
that channel width, width depth ratio, bankfull area, and gradient are significantly
greater downstream of Boomer Creek than upstream, as tested at the 0.05 level of
significance. It also was hypothesized that mean depth and sinuosity are significantly less downstream as compared to upstream.
STUDY AREA
Stillwater Creek Basin is located in Payne, Noble, and Logan counties in central
Oklahoma and has a drainage area of 733 km2. This basin is characterized by a
humid subtropical climate and Red Permian shales and sandstones as main bedrock
types, dominated by red iron oxides (Johnson, 1996). Lake Carl Blackwell, Lake
McMurtry, and Boomer Lake are three reservoirs located in this basin. Two of these
DOWNSTREAM EFFECTS OF URBANIZATION
189
reservoirs are located upstream of the urban area of the City of Stillwater. The largest
(14.2 km2) of these reservoirs is Lake Carl Blackwell, which was built in 1932 for
recreation and as a secondary source of water for Oklahoma State University. Lake
McMurtry (5.26 km2) was built for fishing, flood control, and recreation. Boomer
Lake (1 km2 area), named after Boomer Creek, primarily serves for recreation and
cooling an electricity plant.
Stillwater Creek basin is an urbanizing basin that supports agricultural land (pasture, grassland, and crops) and expanding impervious area (4%). It is dominated by
the Mollisol soil order (MRLC Consortium, 2001). A significant portion of the watershed includes grassland/pasture, followed by deciduous forest dominated by elm,
oak, pecan, and cottonwood. In 1889, Stillwater was established in a fertile valley
at the confluence of two streams now known as Boomer and Stillwater creeks
(Bivert, 1988). What impressed the settlers the most was the fact that these two
streams never ran dry and were surrounded by fertile land (Cunningham, 1979;
Bivert, 1988). At that time, this basin was completely rural, with substantial area
under cropping systems (Fitzpatrick et al., 1939; USDA, 1969). Since then, the population of Stillwater increased from 300 in 1890, to 5962 in 1920, and to 41,320
(estimated) in 2003 (U. S. Census Bureau, 2007). This increase in population served
as the primary reason for the rural-to-urban transformation in this basin. The
expanding campus of Oklahoma State University in Stillwater is another factor
responsible for the increase of impervious surface area in this basin. Runoff generated from impervious areas enters Stillwater Creek through Boomer Creek. Therefore, the confluence of Boomer Creek makes a good dividing point for comparing
upstream and downstream effects on the main channel.
METHODS
Field Data
The main channel was divided into 30 reaches according to sinuosity and confluence of new tributaries. Channel cross-sections and riparian vegetation were
measured at the beginning of each reach along Stillwater Creek. The channel
cross-section measurements included channel width and depth at bankfull stage.
Channel cross-section measurements also included identification of channel bank
materials (by visual observation), the presence or absence of woody debris jams,
and channel type according to the Rosgen Classification of Natural Rivers (Rosgen,
1996). The Rosgen classification provided a common language for describing the
two sections of this river.
Channel morphology data were used to calculate hydraulic variables, such as
mean bankfull depth and bankfull area. Other stream variables, such as sinuosity
and gradient, were calculated from U.S. Geological Survey digital elevation models
(DEMs) using ArcGIS 9.3. An inventory of riparian vegetation also was prepared
that consisted of a transect perpendicular to the channel, located near the beginning of each reach (Moore et al., 2002). These transects were 5 m wide and 30 m
long, divided into three 10-meter long sections. Measurements within each riparian transect recorded area under grass, shrubs, percent canopy cover, and number
190
KANG ET AL.
of trees. Riparian surveys also were conducted at 30 sites along the stream. In addition, a small airplane was used to get a better view of contemporary land cover in
the study area.
Sub-basin Delineation and Land Cover Data
Boundaries of various sub-basins contributing water to surveyed reaches were
delineated using ArcView Soil and Water Assessment Tool (AVSWAT©), which is an
ArcView extension and a graphical user interface for the Soil and Water Assessment
Tool (SWAT©) (Luzio et al., 2002). The National Land Cover Dataset (NLCD) for the
year 2001 was used to map and measure the area under impervious cover and other
types of land cover, such as open water, pervious though developed, impervious
cover, barren land, deciduous forest, grassland, pasture/hay, and cultivation for
each sub-basin. Shapefiles of impervious areas from the City of Stillwater were used
to validate the NLCD-generated impervious area estimates. Aerial photographs for
1973 and 2003 were compared to calculate change in total impervious area and
riparian corridor with the help of raster calculator tool in ArcGIS.
Statistical Analysis
The statistical analysis was completed in two steps using an α = 0.05. Step one
compared variables measured in upstream and downstream sections, and step two
explained differences in any variables from upstream to downstream sections. Step
one applied an ANCOVA (Analysis of Covariance) to compare channel morphology
variables for the two sections. In such an analysis, differences in channel morphology may result from increasing runoff due to increasing drainage area downstream
(Downs and Gregory, 2004). To avoid that problem, channel morphology variables
were normalized based on drainage area by using drainage area as the covariate in
the ANCOVA test. Since ANCOVA is a parametric test based upon an assumption
of normality, eight levels of transformation (original units, square root, cube root,
logarithm, reciprocal root, reciprocal, cube, and square) were used for each geomorphic variable to select the most normal level as suggested by Helsel and Hirsch
(2002). Table 1 shows the transformation selected for each variable. Step two developed a multiple linear regression model for each variable that differed from
upstream to downstream sections. The backward elimination method was used in
developing these regression models (Helsel and Hirsch, 2002).
RESULTS
Based on the field surveys, glide appeared to be the main channel unit type and
bank materials were predominantly fine-grained (Table 2). The channel bed and
bank materials did not change over the entire length of Stillwater Creek; they consisted of 95–100% silt-clay throughout. The shape of channel cross-sections was
parabolic with low gradient. At the same time, there was no difference in the bedrock from upstream to downstream. According to the Rosgen Classification, Stillwater
Creek was classified as an E6b channel, which is a very stable channel type with
DOWNSTREAM EFFECTS OF URBANIZATION
191
Table 1. Transformations Selected for Comparing
Upstream and Downstream Channel Sections
of Stillwater Creek
Variable
Width
Transformation used in
ANCOVA
Natural log
Mean depth
Reciprocal root
Width–depth ratio
Reciprocal
Bankfull area
Reciprocal
Sinuosity
Reciprocal root
Gradient
Square root
Drainage area
Square root
slight entrenchment (Rosgen, 1996). Field observations also revealed an occasional
woody debris jam dominated by large trees.
Stillwater Creek was characterized as having a thick riparian corridor primarily
bordered by agricultural fields. Each riparian transect was dominated by trees with
a thick canopy, followed by grass and shrubs (Table 3). Major riparian tree species
included American elm (Ulmus americana), cottonwoods (Populus sp.), and green
ash (Fraxinus pennsylvanica). Field work also revealed the presence of old trees
with trunks over 100 cm in the riparian corridor. Most of the riparian corridor was
more than 30 m wide. A study completed by Cross (1950) found a thick riparian
corridor dominated by elm, oak, pecan, and cottonwood in Stillwater Creek basin.
The comparison of aerial photographs for 1973 and 2003 revealed minor changes
in the riparian corridor. Therefore, the riparian corridor in this basin has not experienced any significant change during last few decades.
In the case of land cover, grassland covered more basin area (55.5%) than any
other land cover, followed by deciduous forest (22.2%) in this basin (Fig. 3, Table
4). During the 1979–2003 period, impervious area increased by 65%. The expanding campus of Oklahoma State University was a major factor in such increase. Currently, 3.9% of the total watershed area is under impervious cover, most within the
city limits of Stillwater. The impervious area outside the city limits was primarily
road network. The upstream section of Stillwater Creek Basin was rural, with most
of the area covered by grassland, deciduous forest, cultivated land, and pasture.
Based on the ANCOVA results (Table 5), width, bankfull area, sinuosity, and gradient did not differ significantly between the downstream section of Stillwater
Creek and the upstream section. Therefore, the null hypotheses for these variables
were not rejected. The two variables that exhibited significant differences were
mean depth and width–depth ratio. The hypothesis for decreasing mean depth from
upstream to downstream was based on the argument that the process of urbanization would increase sediment production and aggrade the channel, leading to a
decrease in mean depth. This anticipated change in mean depth was the primary
192
KANG ET AL.
Table 2. Watershed Characteristics for Stillwater Creek
Reach
Areaa Channel Width
number (km2)
unit
(m)
Mean Width–
depth depth Bankfull
Rosgen Bank
ratio area (m2) Sinuosity Gradient type materialb
(m)
1
197.3
Glide
29.6
1.1
32.9
1.3
0.1
C6b
100
2
201.2
Glide
11.2
1.4
7.96
15.6
1.2
0.1
E6b
100
3
221.8
Glide
12.2
2.1
5.9
25.3
1.6
0.1
E6b
100
4
325.4
Glide
65.4
27.6
2.4
1802.0
1.1
0.1
E6b
100
5
330.5
Glide
17.3
4.21
4.1
72.9
1.5
0.0
E6b
100
6
332.1
Glide
21.5
2.2
9.7
48.0
1.3
0.1
E6b
100
7
335.1
Glide
18.8
2.8
6.6
53.0
1.0
0.0
E6b
100
8
337.4
Glide
12.2
2.4
5.0
29.8
1.2
0.0
E6b
100
9
338.3
Glide
64.8
30.9
2.1
2003.0
1.3
0.1
E6b
100
10
340.8
Riffle
15.8
2.4
6.6
37.8
1.9
0.1
E6b
100
11
375.1
Glide
64.0
26.1
2.5
1670.0
1.3
0.1
E6b
100
12
392.1
Glide
17.2
1.7
9.9
30.0
1.1
0.1
E6b
100
13
399.7
Glide
20.2
8.5
2.4
172.0
1.0
0.1
E6b
100
14
418.0
Riffle
8.3
3.3
2.5
27.5
1.5
0.1
E6b
95
15
420.9
Glide
19.9
3.5
5.7
69.8
1.0
0.0
E6b
100
16
423.0
Glide
65.0
27.3
2.4
1772.0
1.1
0.1
E6b
100
17
424.7
Glide
63.8
23.8
2.7
1519.0
1.3
0.1
E6b
100
18
473.6
Glide
18.0
2.0
8.9
36.0
1.6
0.1
E6b
100
19
475.5
Run
13.8
3.1
4.4
43.1
1.2
0.1
E6b
100
20
563.3
Glide
47.1
7.2
6.6
338.0
1.5
0.0
E6b
100
21
570.6
Glide
31.4
5.0
6.3
156.0
1.2
0.1
E6b
100
22
577.1
Glide
63.7
32.5
2.0
2070.0
1.2
0.1
E6b
100
23
586.3
Glide
22.4
3.3
6.9
73.0
1.4
0.0
E6b
100
24
591.0
Run
18.2
6.6
2.8
119.0
1.0
0.0
E6b
100
25
637.1
Glide
8.2
2.9
2.8
24.0
1.4
0.0
E6b
100
26
637.1
Riffle
33.0
11.1
3.0
366.0
1.2
0.0
E6b
100
27
706.0
Glide
31.0
10.2
3.0
316.0
1.0
0.0
E6b
100
28
706.5
Glide
33.0
10.3
3.2
338.0
1.0
0.0
E6b
100
29
732.8
Glide
44.8
13.1
3.4
587.0
1.2
0.0
E6b
100
30
733.1
Glide
34.2
11.0
3.11
378.0
1.1
0.1
E6b
100
a
Watershed area upstream of transect.
Silt + clay %.
b
26.9
193
DOWNSTREAM EFFECTS OF URBANIZATION
Table 3. Riparian Vegetation Characteristics for Stillwater Creek
Reach
number
Shruba (%)
Grassb (%)
Canopy coverc (%)
Number of trees
in riparian transect
1
0
30
23
24
2
6
56
26
32
3
16
16
30
10
4
0
53
53
7
5
3
60
33
13
6
16
73
46
19
7
0
96
40
23
8
5
25
60
34
9
33
26
53
3
10
1
98
36
12
11
0
0
0
0
12
26
36
90
40
13
15
28
60
21
14
16
56
26
13
15
38
45
66
35
16
13
53
40
3
17
0
80
40
11
18
10
43
70
13
19
3
90
60
9
20
20
60
53
3
21
26
36
73
8
22
26
56
26
6
23
0
90
93
15
24
3
90
30
6
25
0
93
63
9
26
13
56
33
3
27
0
13
0
2
28
3
56
6
2
29
41
83
26
6
30
16
56
46
20
a
Percent area of riparian transect under shrub.
Percent area of riparian transect under grass.
c
Percent area of riparian transect under canopy cover.
b
reason for hypothesizing the increasing width–depth ratio. The null hypotheses for
these two variables were rejected—mean depth and width–depth ratio both differ
significantly between upstream and downstream sections of Stillwater Creek.
Differences in mean depth and width–depth ratio were explained with the help of
multiple linear regression (Table 6). In case of mean depth, R2 was low (0.51),
which reflected unexplained variance (Table 6). However, R2 was higher (0.61) in
194
KANG ET AL.
Fig. 3. Land cover in Stillwater Creek Basin (produced from data provided by the U.S. Geological
Survey).
Table 4. Land Cover in Stillwater Creek Basin
Derived from the 2001 National Land Cover Data
Land cover type
Area (%)
Open water
3.1
Pervious though developed
6.4
Impervious
3.9
Deciduous forest
22.2
Grassland/herbaceous
55.5
Pasture /hay
2.6
Cultivated
6.3
Source: MRLC Consortium, 2001.
the case of width–depth ratio. Upstream-to-downstream differences in these variables were not completely explained by urbanization alone. The presence of riparian trees, and of deciduous forest, in this basin were two other factors that may have
contributed to this trend.
According to regression models, these trends were due to multiple factors, such
as urbanization along with riparian trees and deciduous forest in this basin.
Research in other basins has yielded similar results (Leopold, 1972; Hollis, 1976;
195
DOWNSTREAM EFFECTS OF URBANIZATION
Table 5. Upstream and Downstream Comparison of Stillwater Creek
Channel variable compared
Null hypothesis
Actual result
Status of null
hypothesis
(α = 0.05)
Width (natural log)
No difference
No difference
Not rejected
0.29
Mean depth (reciprocal root)
No difference
Decrease
Rejected
0.01
Width–depth ratio (reciprocal)
No difference
Increase
Rejected
0.03
Bankfull area (reciprocal)
No difference
No difference
Not rejected
0.54
Sinuosity (reciprocal root)
No difference
No difference
Not rejected
0.16
Gradient (square root)
No difference
No difference
Not rejected
0.07
p-value
Table 6. Multiple Linear Regression Models Used to Explain Change in Mean
Depth and Width–Depth Ratio from Upstream to Downstream Channel Sections in
Stillwater Creek
Dependent variable, Y
Independent variable, Xi
Coefficient
Mean depth (m)
Width–depth ratio
549
b0
0.50
Impervious areaa
b1
–0.000125
Area under deciduous foresta
b2
1.78
Area under grassland/herbaceousa
b3
b
Riparian trees
a
–134
b4
0.080
17.4
R2
0.51
0.61
Percent of total area.
Number of trees in riparian transects.
b
Nanson, 1981; Montgomery, 1997; Booth and Henshaw, 2001; Hession et al.,
2002). As an urbanizing basin with active construction, the downstream section of
Stillwater Creek was characterized by substantial sediment production and runoff,
while imperviousness did not appear as a significant factor explaining differences
in channel morphology from upstream to downstream. As one moves downstream
from the confluence with Boomer Creek, the tributary that delivered urban runoff
and sediment, none of the downstream factors showed a statistically significant
change that could be attributed to urbanization alone. However, local conditions,
such as riparian trees, deciduous forest, and cohesive bank materials, provided
possible explanations for the lack of difference in the majority of the response
variables.
196
KANG ET AL.
Fig. 4. Images of upstream and downstream sections of Stillwater Creek showing similar riparian
vegetation and geomorphic characteristics.
DISCUSSION
Despite a 65% increase in the impervious area in 24 years (1979–2003), the
majority of variables do not show any significant change in the downstream section
of Stillwater Creek. Mean depth and width–depth ratio are the only variables showing significant differences between the upstream and downstream sections. As
revealed by multiple linear regression, differences in these variables can be attributed to a combination of land cover types, which rule out imperviousness as a
major explanatory variable.
The presence of riparian trees (Fig. 4) can provide some explanation for differences in mean depth and width-depth ratio. Tree density, in combination with
cohesive bed and bank material, may have helped stabilize the banks against
erosion and provided woody debris for trapping and depositing sediments, thus
leading to a decrease in mean channel depth downstream. Informal discussions
with Mr. Bud Payne, who spent most of his life in Stillwater, revealed that the riparian corridor and channel geometry of Stillwater Creek have not changed substantially in the last five decades, despite urban growth. The intact stream banks of
Boomer Creek, the main tributary bringing urban runoff into Stillwater Creek,
showed no structural change after the severe flooding of summer 2007 (Fig. 5).
Such geomorphic characteristics support the decisive role of local conditions, such
as riparian trees, cohesive bank materials, occasional woody debris jams, and
entrenchment (Montgomery, 1999; Kang and Marston, 2006). Although Fryirs and
DOWNSTREAM EFFECTS OF URBANIZATION
197
Fig. 5. A thick riparian corridor dominated by trees on the banks of Boomer Creek helps protect the
stream bank from erosion.
Brierley (2000) suggested that urbanization leads to irreversible alterations in
stream channels, such alterations were not evident in this stream. Overlaid on the
sandstone bedrock with some shale, Stillwater Creek is conveying runoff and sediment without any notable change in channel morphology; this type of channel
response is unlike the findings of Hession et al. (2002), Pizzuto et al. (2000),
Trimble (1997), or Fryirs and Brierley (2000).
Another reason this channel has not responded dramatically to urbanization
could be related to the parabolic channel cross-sections of the downstream section.
A parabolic cross-section has been shown to be the equilibrium shape based on
threshold theory (Stevens, 1989), models of lateral diffusion (Parker, 1978), minimum stream power (Chang, 1980), and minimum variance (Langbein, 1965). This
stream experienced entrenchment during the early 20th century for reasons other
than urbanization. At present, the entrenched parabolic cross-sections carved into
the cohesive shales and clay and combined with the soil-binding effect of streamside vegetation, appear insensitive to the hydrologic and sediment impacts from
urbanization. These results lay a foundation for understanding this unique geomorphic behavior. These findings also present a solid base for future research to
develop generalizations about the geomorphic response of urbanizing streams in
the Central Redbed Plains of Oklahoma.
198
KANG ET AL.
CONCLUSIONS
Local conditions play a decisive role in countering the effects of urbanization in
this basin. The soil-binding effect of streamside vegetation, banks comprised of
cohesive clays, and a parabolic cross section have combined to create a channel
morphology (as measured by width, gradient, bankfull area, and sinuosity) that is
stable despite the increased runoff and sediment supplied by the Stillwater urban
area. The finding that channel morphology does not change downstream from the
Stillwater urban area reminds us that place matters when understanding the impacts
of urbanization on stream channels. One must be mindful of the resisting framework as well as the driving forces when analyzing urban impacts on streams. In the
Central Redbed Plains of Oklahoma, streams are able to counter the impacts of
increased runoff and sediment due to urbanization.
Contrary to the findings of Fryirs and Brierley (2000), urbanization within in the
Stillwater Creek basin has not led to anticipated dramatic changes in the geomorphic system. These findings are consistent with Montgomery (1999) and Kang and
Marston (2006), who argued that local conditions must be considered in any such
analysis. Klein (1979) argued various measures to limit the adverse effects of urbanization on streams; however, in this geomorphic province, the decisive role of local
conditions in countering such effects of urbanization advocates the place dependency of such measures. This research offers a unique, detailed data set in the
south-central United States. The observed site-specific geomorphic response of
Stillwater Creek to imperviousness can provide guidance in devising river management practices in this geomorphic province.
Acknowledgements: The authors sincerely thank Dr. Carol Harden, Dr. John C. Dixon, and anonymous reviewers for providing constructive comments on this manuscript. We also thank Brandon
Binford, Chris Ennen, Mike Othitis, and Kate Lehmert for assisting with field work. Earlier review of this
manuscript by Dr. Thomas Foggin is sincerely appreciated.
REFERENCES
Arnold, C. L. J. and Gibbons, C. J. (1996) Impervious surface coverage: The emergence of a key environmental indicator. Journal of American Planning Association, Vol. 62, 243–258.
Avolio, C. M. (2003) Local Impacts of Road Crossings on Puget Lowland Creeks.
Unpublished master's thesis, Department of Civil and Environmental Engineering, University of Washington, Seattle.
Bivert, R.E. (1988) My Town Stillwater: A Quick Fact Review of Stillwater, Oklahoma
on Its 100th Anniversary. Stillwater, OK: Copy & Art.
Booth, D. B. (1990) Stream channel incision following drainage basin urbanization.
Water Resources Bulletin, Vol. 26, 407–417.
Booth, D. B. (1991) Urbanization and the natural drainage system: Impacts, solutions, and prognoses. The Northwest Environmental Journal, Vol. 7, 93–118.
Booth, D. B. and Henshaw, P. C. (2001) Rates of channel erosion in small urban
streams. In S. W. Mark and J. B. Stephen, eds., Landuse and Watersheds: Human
DOWNSTREAM EFFECTS OF URBANIZATION
199
Influence on Hydrology and Geomorphology in Urban and Forest Areas.
Washington, DC: American Geophysical Union, 17–38.
Booth, D. B. and Jackson, C.R. (1997) Urbanization of aquatic systems: Degradation thresholds, stormwater detention, and the limits of mitigation. Journal of the
American Water Resources Association, Vol. 33, 1077–1090.
Brierley, G. J. and Fryirs, K. A. (2005). Geomorphology and River Management.
Malden, MA: Blackwell.
Chang, H. H. (1980) Geometry of gravel streams. Journal of Hydraulics Division of
American Society of Civil Engineers, Vol. 106, 1443–1456.
Charbonneau, R. and Resh, V. H. (1992) Strawberry Creek on the University of
California, Berkeley Campus: A case history of urban stream restoration. Aquatic
Conservation: Marine and Freshwater Ecosystems, Vol. 2, 292–307.
Chin, A. (2006) Urban transformation of river landscapes in global context. Geomorphology, Vol. 79, 460–487.
Chin, A. and Gregory, K. J. (2001) Urbanization and adjustment of ephemeral
stream channels. Annals of the Association of American Geographers, Vol. 91,
595–608.
Cross, F. B. (1950) Effects of sewage and of a headwaters impoundment on the
fishes of Stillwater Creek in Payne County, Oklahoma. American Midland Naturalist, Vol. 43, 128–145.
Cunningham, R. E. (1979). Stillwater: Where Oklahoma Began. Stillwater, OK:
Evans Publications.
Douglas, I. (1974) The impact of urbanization on river systems. In Proceedings of
the International Geographical Union Regional Conference and Eighth New
Zealand Geography Conference, 307–317.
Downs, P. W. and Gregory, K. J. (2004). River Channel Management: Towards Sustainable Catchment Hydrosytems. London, UK: Arnold.
Fitzpatrick, E. G., Boatright, W. C., and Rose, L. E. (1939). Soil Survey: Garfield
Country, Oklahoma. Washington, DC: U.S. Department of Agriculture.
Fryirs, K. and Brierley, G. (2000) A geomorphic approach to the identification of
river recovery potential. Physical Geography, Vol. 21, 244–277.
Gregory, K. J. and Park, C. C. (1976) Stream channel morphology in northwest
Yorkshire. Revue de Geomorphologie Dynamique, Vol. 25, 63–72.
Gurnell, A., Lee, M., and Souch, C. (2007) Urban rivers: Hydrology, geomorphology, ecology, and opportunities for change. Geography Compass, Vol. 1, 1118–
1137.
Hammer, T. A. (1972) Stream channel enlargement due to urbanization. Water
Resources Research, Vol. 8, 1530–1540.
Helsel, D. R. and Hirsch, R. M. (2002). Statistical Methods in Water Resources.
Reston, VA: U.S. Geological Survey.
Hession, W. C., Pizzuto, J. E., Johnson, T. E., and Horwitz, R. J. (2002) Influence of
bank vegetation on channel morphology in rural and urban watersheds. Geology,
Vol. 31, 147–150.
Hollis, G. E. (1976) The response of natural river channels to urbanization: Two
case studies in southeast England. Journal of Hydrology, Vol. 30, 351–363.
200
KANG ET AL.
Jeje, L. K. and Ikeazota, S. I. (2002) Effects of urbanization on channel morphology:
The case of Ekulu River in Enugu, southeastern Nigeria. Singapore Journal of
Tropical Geography, Vol. 23, 37–51.
Johnson, K. S. (1996) Geology of Oklahoma. In K. S. Johnson and N. H. Suneson,
eds., Rockhounding and Earth-Science Activities in Oklahoma, 1995 Workshop.
Oklahoma City, OK: Oklahoma Geological Society, 1–9.
Johnson, M. P. (2001) Environmental impacts of urban sprawl: A survey of the literature and proposed research agenda. Environment and Planning A, Vol. 33, 717–
735.
Kang, R. S. and Marston, R. A. (2006) Geomorphic effects of rural-to-urban land use
conversion on three streams in the Central Redbed Plains of Oklahoma. Geomorphology, Vol. 79, 488–506.
Keen-Zebert, A. (2007) Channel response to urbanization: Scull and Mud creeks in
Fayetteville, Arkansas. Physical Geography, Vol. 28, 249–260.
Klein, R. D. (1979) Urbanization and stream quality impairment. Water Resources
Bulletin, Vol. 15, 948–963.
Langbein, W. B. (1965) Geometry of river channels: closure of discussion. Journal
of the Hydraulics Division of American Society of Civil Engineers, Vol. 91, 297–
313.
Leopold, L. B. (1968) Hydrology For Urban Land Planning—A Guidebook on the
Hydrologic Effects of Urban Land Use. Washington, DC: U. S. Department of
Interior, U.S. Geological Survey Circular 554.
Leopold, L. B. (1972) River channel change with time: An example. Geological
Society of America Bulletin, Vol. 84, 845–860.
Li, Y. and Wang, C. (2009) Impacts of urbanization on surface runoff of the
Dardenne Creek watershed, St. Charles County, Missouri. Physical Geography,
Vol. 30, 556–573.
Luzio, M. D., Srinivasan, R., Arnold, J. D., and Neitsch, S. L. (2002). ArcView Interface for SWAT 2000: User’s Guide. College Station, TX: Texas Water Resources
Institute.
Marston, R. A. (2006) Ecoregions: A geographic advantage in studying environmental change. AAG Newsletter, Vol. 41, 6.
May, C. W., Horner, R. R., Karr, J. R., Mar, B. W., and Welch, E. B. (2002) Effects of
urbanization on small streams in the Puget Sound ecoregion. In T. R. Schueler
and H. K. Holland, eds., The Practice of Watershed Protection. Ellicott City, MD:
Center for Watershed Protection, 87–98.
Montgomery, D. R. (1997) What’s best on the banks? Nature, Vol. 388, 328–329.
Montgomery, D. R. (1999) Process domains and the river continuum. Journal of the
American Water Resources Association, Vol. 35, 397–410.
Moore, K., Jones, K., and Dambancher, J. (2002) Aquatic Inventories Project, Natural Production Program. Corvallis, OR: Oregon Department of Fish and Wildlife.
Morisawa, M. and Laflure, E. (1979) Hydraulic geometry, stream equilibrium and
urbanization. In D. D. Rhodes and G. P. Williams, eds., Adjustments of the
Fluvial System. Dubuque, IA, USA: Kendall/Hunt, 333–350.
MRLC Consortium (2001). National Land Cover Dataset. Reston, VA: U.S. Geological Survey.
DOWNSTREAM EFFECTS OF URBANIZATION
201
Nanson, G. C. (1981) Downstream reduction of rural channel size with contrasting
urban effects in small coastal streams southeastern Australia. Journal of Hydrology, Vol. 52, 230–255.
O’Driscoll, M. A., Soban, J. R., and Lecce, S. A. (2009) Stream channel enlargement
response to urban land cover in small coastal plain watersheds, North Carolina.
Physical Geography, Vol. 30, 528–555.
Orme, A. R. and Bailey, R. G. (1971) Vegetation conversion and channel geometry
in Monroe Canyon, Southern California. Yearbook of the Association of Pacific
Coast Geographers, Vol. 33, 65–82.
Parker, G. (1978) Self-formed straight rivers with equilibrium banks and mobile bed.
Journal of Fluid Mechanics, Vol. 89, 127–146.
Paul, M. J. and Meyer, J. L. (2001) Streams in the urban landscape. Annual Review
of Ecology, Vol. 32, 333–365.
Pizzuto, J. E., Hession, W. C., and McBride, M. (2000) Comparing gravel bed rivers
in paired urban and rural catchments of southeastern Pennsylvania. Geology,
Vol. 28, 79–82.
Rosgen, D. (1996). Applied River Morphology. Pagosa Springs, CO: Wildland
Hydrology.
Stevens, M. A. (1989) Width of straight alluvial channels. Journal of Hydraulic Engineering, Vol. 115, 309–326.
Trimble, S. W. (1997) Contribution of stream channel erosion to sediment yield
from an urbanizing watershed. Science, Vol. 278, 1442–1444.
U. S. Census Bureau (2007). American FactFinder Dataset. Suitland, MD: U.S.
Census Bureau.
Urban, M. C., Skelly, D. K., Burchsted, D., Price, W., and Lowry, S. (2006) Stream
communities across a rural-urban landscape gradient. Diversity and Distributions, Vol. 12, 1–14.
USDA (1969). Soil Survey: Oklahoma County, Oklahoma. Washington, DC: U.S.
Department of Agriculture.
Wolman, M. G. (1967) A cycle of sedimentation and erosion in urban river channels. Geografiska Annaler Series A, Vol. 49A, 385–395.