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Last updated: 9/2/10
This list includes resources for understanding
how urban development and imperious surface cover effect
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Review Articles
General / Multiple Effects
Toxicity and Pesticides
Nutrients and Chloride
Habitat Characteristics
Thermal Impacts
Direct Channel Impacts
Aquatic Habitat Integrity
Benthic Macroinvertebrates
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Allan, J.D. 2004. Landscapes and riverscapes: The influence
of land use on stream ecosystems. Annual Review of
Ecology, Evolution and Systematics 35: 257-84.
Abstract: Local habitat and biological diversity of
streams and rivers are strongly influenced by landform and
land use within the surrounding valley at multiple scales.
However, empirical associations between land use and stream
response only varyingly succeed in implicating pathways of
influence. This is the case for a number of reasons, including
(a) covariation of anthropogenic and natural gradients in the
landscape; (b) the existence of multiple, scale-dependent
mechanisms; (c) nonlinear responses; and (d) the difficulties
of separating present-day from historical influences. Further
research is needed that examines responses to land use under
different management strategies and that employs response
variables that have greater diagnostic value than many of the
aggregated measures in current use.
Available online.
Abstract: Local habitat and biological diversity of
streams and rivers are strongly influenced by landform and
land use within the surrounding valley at multiple scales.
However, empirical associations between land use and stream
response only varyingly succeed in implicating pathways of
influence. This is the case for a number of reasons, including
(a) covariation of anthropogenic and natural gradients in the
landscape; (b) the existence of multiple, scale-dependent
mechanisms; (c) nonlinear responses; and (d) the difficulties
of separating present-day from historical influences. Further
research is needed that examines responses to land use under
different management strategies and that employs response
variables that have greater diagnostic value than many of the
aggregated measures in current use.
Available online.
Barnes, K.
B., J. M. Morgan III, and M. C. Roberge. 2002.
Impervious surfaces and the quality of natural and built
environments. Baltimore, Md. : Department of Geography and
Environmental Planning, Towson University. 28 p.
The growth
and spread of impervious surfaces within urbanizing watersheds
pose significant threats to the quality of natural and built
environments. These threats include increased stormwater
runoff, reduced water quality, higher maximum summer
temperatures, degraded and destroyed aquatic and terrestrial
habitats, and the diminished aesthetic appeal of streams and
landscapes. This paper provides a basic introduction to
impervious surfaces and an overview of the environmental
effects of increased watershed imperviousness, with particular
consideration given to the watershed of the Chesapeake Bay.
Available online.
Beach, D.
2002. Coastal sprawl: the effects of urban design on
aquatic ecosystems in the
Pew Oceans Commission, Arlington, Virginia. 33 p.
discussion of effects of imperviousness on habitat, water
temperature, pollutants, and aquatic life (p. 9-11).
Available online. Also
available at the DNR Library.
K., and K. Brown. 2001. Impervious cover and land use in
Bay watershed.
Center for Watershed Protection, Ellicott City, MD. 51 p.
Includes "Literature review of the impervious
cover/stream quality relationship" (Appendix A, p. 33-42).
at the DNR Library.
Center for
Watershed Protection. 2003. Impacts of impervious cover on
aquatic systems. Center for Watershed Protection, Ellicott
City, MD. 141 p.
Reviews more than 225 research studies that have explored the
impact of impervious cover and other indicators of
urbanization on aquatic systems. Comprehensively reviews the
available scientific data on how urbanization influences
hydrologic, physical, water quality, and biological indicators
of aquatic health as of late 2002.
Available in the DNR Library.
T. 2001. Watershed characteristics and aquatic ecological
integrity: A literature review. TNC Freshwater Initiative.
12 p.
This document summarizes the findings of currently available
research on the relationship between watershed characteristics
and aquatic Indicators of Biotic Integrity (IBIs). It covers
the results of empirical research, the practical implications
for TNC s work, and future research needs. The section on
practical implications primarily discusses the thresholds and
indicators that have been developed to analyze the impact of
watershed impervious area on IBIs. Future research needs
include the development of better indicators and thresholds
for the impacts of agriculture, dams, and point sources; and
the role of habitat type in determining which indicators are
relevant. An appendix is included with brief summaries of the
key findings in the articles reviewed.
Available online.
M.P. 2001. Environmental impacts of urban sprawl: a survey
of the literature and proposed research agenda.
Environment and Planning A 33: 717-735.
'Urban sprawl' has recently become a subject of popular debate
and policy initiatives from governmental bodies and nonprofit
organizations. However, there is little agreement on many
aspects of this phenomenon: its definition, its impacts - both
nonmonetary and monetary - economic and policy models that
predict the presence of sprawl, and decision-support models
that could assist policymakers in evaluating alternative
development schemes that may have characteristics of sprawl.
In particular, there is relatively little research on urban
sprawl that focuses specifically on measurement and modeling
of environmental impacts. The purpose of this paper is
twofold: to survey the literature on urban sprawl, with a
focus on environmental aspects and to identify a research
agenda that might result in a greater number of anaytical
tools for academics and practitioners to characterize,
monetize, model, and make planning decisions about sprawl.
Available online.
T.R. and H.K. Holland. 1994. The importance of
imperviousness. Watershed Protection Techniques 1(3):
100-111. (Also published in The Practice of Watershed
"Review of key findings of urban stream studies examining the
relationship of urbanization on stream quality" (Table 2, p.
105), showing that "stream degradation occurs at relatively
low levels of imperviousness (10-20%)"
Available in the DNR library's journals collection.
General /
Multiple Effects
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Arnold, C.
L., and C. J. Gibbons. 1996. Impervious surface coverage:
the emergence of a key environmental indicator. Journal of
the American Planning Association 62:243-258.
Planners concerned with water resource protection in
urbanizing areas must deal with the adverse impacts of
polluted runoff. Impervious surface coverage is a quantifiable
land-use indicator that correlates closely with these impacts.
Once the role and distribution of impervious coverage are
understood, a wide range of strategies to reduce impervious
surfaces and their impacts on water resources can be applied
to community planning, site-level planning and design, and
land use regulation. These strategies complement many current
trends in planning, zoning, and landscape design that go
beyond water pollution concerns to address the quality of life
in a community.
DNR employees should
library to request via interlibrary loan.
Brown, L.R.
Cuffney, T.F., Coles, J.F., Fitzpatrick, Faith, McMahon,
Gerard, Steuer, J.J., Bell, A.H., and May, J.T. 2009. Urban
streams across the
lessons learned from studies in 9 metropolitan areas.
J. N. Am. Benthol. Soc. 28(4):1051–1069.
Studies of the effects of urbanization on stream ecosystems
have usually focused on single metropolitan areas. Synthesis
of the results of such studies have been useful in developing
general conceptual models of the effects of urbanization, but
the strength of such generalizations is enhanced by applying
consistent study designs and methods to multiple metropolitan
areas across large geographic scales. We summarized the
results from studies of the effects of urbanization on stream
ecosystems in 9 metropolitan areas across the US (Boston,
Massachusetts; Raleigh, North Carolina; Atlanta, Georgia;
Birmingham, Alabama; Milwaukee-Green Bay, Wisconsin; Denver,
Colorado; Dallas-Fort Worth, Texas; Salt Lake City, Utah; and
Portland, Oregon). These studies were conducted as part of the
US Geological Survey's National Water-Quality Assessment
Program and were based on a common study design and used
standard sample-collection and processing methods to
facilitate comparisons among study areas. All studies included
evaluations of hydrology, physical habitat, water quality, and
biota (algae, macroinvertebrates, fish). Four major
conclusions emerged from the studies. First, responses of
hydrologic, physical-habitat, water-quality, and biotic
variables to urbanization varied among metropolitan areas,
except that insecticide inputs consistently increased with
urbanization. Second, prior land use, primarily forest and
agriculture, appeared to be the most important determinant of
the response of biota to urbanization in the areas we studied.
Third, little evidence was found for resistance to the effects
of urbanization by macroinvertebrate assemblages, even at low
levels of urbanization. Fourth, benthic macroinvertebrates
have important advantages for assessing the effects of
urbanization on stream ecosystems relative to algae and
fishes. Overall, our results demonstrate regional differences
in the effects of urbanization on stream biota and suggest
additional studies to elucidate the causes of these underlying
Available online through the DNR Library's subscription.
Coles, J.F.,
Cuffney, T. F., McMahon, G., and Beaulieu, K.M. 2004. The
effects of urbanization on the biological, physical, and
chemical characteristics of coastal
England streams.
U.S. Geological Survey, Professional Paper 1695, 47 p.
During August 2000, responses of biological communities
(invertebrates, fish, and algae), physical habitat, and water
chemistry to urban intensity were compared among 30 streams
within 80 miles of Boston, Massachusetts. Sites chosen for
sampling represented a gradient of the intensity of urban
development (urban intensity) among drainage basins that had
minimal natural variability. In this study, spatial
differences were used as surrogates for temporal changes to
represent the effects of urbanization over time. The degree of
urban intensity for each drainage basin was characterized with
a standardized urban index (0-100, lowest to highest) derived
from land cover, infrastructure, and socioeconomic variables.
Multivariate and multimetric analyses were used to compare
urban index values with biological, physical, and chemical
data to determine how the data indicated responses to
urbanization. Multivariate ordinations were derived for the
invertebrate-, fish-, and algae-community data by use of
correspondence analysis, and ordinations were derived for the
chemical and physical data by use of principal-component
analysis. Site scores from each of the ordinations were
plotted in relation to the urban index to test for a response.
In all cases, the primary axis scores showed the strongest
response to the urban index, indicating that urbanization was
a primary factor affecting the data ordination. For the
multimetric analyses, each of the biological data sets was
used to calculate a series of community metrics. For the sets
of chemical and physical data, the individual variables and
various combinations of individual variables were used as
measured and derived metrics, respectively. Metrics that were
generally most responsive to the urban index for each data set
included: EPT (Ephemeroptera, Plecoptera, Trichoptera) taxa
for invertebrates; cyprinid taxa for fish; diatom taxa for
algae; bicarbonate, conductivity, and nitrogen for chemistry;
and water depth and temperature for physical habitat. The
slopes of the responses generally were higher between the
urban index values of 0 to 35, indicating that the greatest
change in aquatic health may occur between low and moderate
levels of urban intensity. Additionally, many of the responses
showed that at urban index values greater than 35, there was a
threshold effect where the response variable no longer changed
with respect to urban intensity. Recognizing and understanding
this type of response is important in management and
monitoring programs that rely on decisive interpretations of
variable responses. Any biological, physical, or chemical
variable that is used to characterize stream health over a
gradient of disturbance would not be a reliable indicator when
a level of disturbance is reached where the variable does not
respond in a predictable manner.
M.B., and Calhoun, D.L. 2007. Physical, Chemical, and
Biological Responses of Streams to Increasing Watershed
Urbanization in the Piedmont Ecoregion of
and Alabama, 2003.
U.S. Geological Survey Scientific Investigations Report
As part of the U.S. Geological Survey National Water-Quality
Assessment Program's effort to assess the physical, chemical,
and biological responses of streams to urbanization, 30
wadable streams were sampled near Atlanta, Ga., during
2002–2003. Watersheds were selected to minimize natural
factors such as geology, altitude, and climate while
representing a range of urban development. A multimetric urban
intensity index was calculated using watershed land use, land
cover, infrastructure, and socioeconomic variables that are
highly correlated with population density. The index was used
to select sites along a gradient from low to high urban
intensity. Response variables measured include stream
hydrology and water temperature, instream habitat, field
properties (pH, conductivity, dissolved oxygen, turbidity),
nutrients, pesticides, suspended sediment, sulfate, chloride,
Escherichia coli (E. coli) concentrations, and
characterization of algal, invertebrate and fish communities.
In addition, semipermeablemembrane devices (SPMDs)—passive
samplers that concentrate hydrophobic organic contaminants
such as polycyclicaromatic hydrocarbons (PAHs)—were used to
evaluate water-quality conditions during the 4 weeks prior to
biological sampling. Changes in physical, chemical, and
biological conditions were evaluated using both nonparametric
correlation analysis and nonmetric multidimensional scaling
(MDS) ordinations and associated comparisons of dataset
similarity matrices.
A. F., D. M. Sanger, C. P. Gawle, S. B. Lerberg, M. S.
Santiago, G. H. M. Riekerk, L. E. Zimmerman, and G. I. Scott.
2004. Linkages between tidal creek ecosystems and the
landscape and demographic attributes of their watersheds.
Journal of Experimental Marine Biology and Ecology
Twenty-three headwater tidal creeks draining watersheds
representative of forested, suburban, urban, and industrial
land cover were sampled along the South Carolina coast from
1994 to 2002 to: (1) evaluate the degree to which impervious
land cover is an integrative watershed-scale indicator of
stress; (2) synthesize and integrate the available data on
linkages between land cover and tidal creek environmental
quality into a conceptual model of the responses of tidal
creeks to human development; and (3) use the model to develop
recommendations for conserving and restoring tidal creek
ecosystems. The following parameters were evaluated: human
population density, land use, impervious cover, creek physical
characteristics, water quality, sediment chemical
contamination and grain size characteristics, benthic
chlorophyll a levels, porewater ammonia concentration, fecal
coliform concentration, and macrobenthic and nekton population
and community characteristics. The
conceptual model was developed and used to identify the
linkages among watershed-scale stressors, physical and
chemical exposures, and biological responses of tidal creeks
to human development at the watershed scale. This model
provides a visual representation of the manner in which human
population growth is linked to changes in the physiochemical
environment and ultimately the nursery habitat function of
tidal creeks and the safety of seafood harvested from
headwater tidal creeks. The ultimate stressor on the tidal
creek ecosystem is the human population density in the
watershed and associated increases in the amount of impervious
land cover. Measurable adverse changes in the physical and
chemical environment were observed when the impervious cover
exceeded 10–20% including altered hydrography, changes in
salinity variance, altered sediment characteristics, increased
chemical contaminants, and increased fecal coliform loadings.
Living resources responded when impervious cover exceeded
20–30%. The impacts on the living resources included reduced
abundance of stress-sensitive macrobenthic taxa, reduced
abundance of commercially and recreationally important shrimp,
and altered food webs. Headwater tidal creeks appear to
provide early warning of ensuing harm to larger tidal creeks,
tidal rivers and estuaries, and the amount of impervious cover
in a watershed appears to be an integrative measure of the
adverse human alterations of the landscape. Through education
and community involvement, a conservation ethic may be
fostered that encourages the permanent protection of lands for
the services they provide.
May, C. R.,
Horner, J., Karr, B., Mar, B. W., and E. Welch. 1997.
Effects of Urbanization on Small Streams
in the
Puget Sound
Lowland Ecoregion.
Watershed Protection Techniques 2(4): 483-494.
Key finding: Physical and
biological stream indicators declined most rapidly during the
initial phase of the urbanization process as the percentage of
total impervious area exceeded the 5-10% range (Washington).
employees should
library to request via interlibrary loan.
J.B. 1991. Collective effects of development on the marine
environment. Oceanologica Acta 11:287-298.
This paper identifies issues associated with effects of
industrialization and urbanization on the marine environment.
Emphasis is given to the collective effects of development and
impacts on living marine resources. Issues of concern include
inorganic and organic contaminants, nutrient enrichment and
eutrophication, physical degradation of habitat, and non-point
sources of stresses. Conclusions are based on case studies and
include solutions as these are being practiced.
A. P., P. L. Angermeier, and A. E. Rosenberger. 2005.
Impacts of new highways and subsequent landscape urbanization
on stream habitat and biota. Reviews in Fisheries Science
New highways are pervasive, pernicious threats to stream
ecosystems because of their short- and long-term physical,
chemical, and biological impacts. Unfortunately, standard
environmental impact statements (EISs) and environmental
assessments (EAs) focus narrowly on the initial direct impacts
of construction and ignore other long-term indirect impacts.
More thorough consideration of highway impacts, and,
ultimately, better land use decisions may be facilitated by
conceptualizing highway development in three stages: initial
highway construction, highway presence, and eventual landscape
urbanization. Highway construction is characterized by
localized physical disturbances, which generally subside
through time. In contrast, highway presence and landscape
urbanization are characterized by physical and chemical
impacts that are temporally persistent. Although the impacts
of highway presence and landscape urbanization are of similar
natures, the impacts are of a greater magnitude and more
widespread in the urbanization phase. Our review reveals that
the landscape urbanization stage is clearly the greatest
threat to stream habitat and biota, as stream ecosystems are
sensitive to even low levels (< 10%) of watershed urban
development. Although highway construction is ongoing,
pervasive, and has severe biological consequences, we found
few published investigations of its impacts on streams.
Researchers know little about the occurrence, loading rates,
and biotic responses to specific contaminants in highway
runoff. Also needed is a detailed understanding of how highway
crossings, especially culverts, affect fish populations via
constraints on movement and how highway networks alter natural
regimes (e.g., streamflow, temperature). Urbanization research
topics that may yield especially useful results include a) the
relative importance and biological effects of specific
components of urban development—e.g., commercial or
residential; b) the scenarios under which impacts are
reversible; and c) the efficacy of mitigation measures—e.g.,
stormwater retention or treatment and forested buffers.
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Hollis, F.
1975. The effects of urbanization on floods of different
recurrence intervals. Water Resources Research,
Increased bankfull discharge. Bankfull discharge increased two
to five times after urbanization.2
Studies have shown that the urbanization of a catchment can
drastically change the flood characteristics of a river.
Published results are synthesized to show the general
relationship between the increase in flood flows following
urbanization and both the percentage of the basin paved and
the flood recurrence interval. In general, (1) floods with a
return period of a year or longer are not affected by a 5%
paving of their catchment, (2) small floods may be increased
by 10 times by urbanization, (3) floods with a return period
of 100 yr may be doubled in size by a 30% paving of the basin,
and (4) the effect of urbanization declines, in relative
terms, as flood recurrence intervals increase.
Konrad, C.
P., and D. B. Booth. 2005. Hydrologic changes in urban
streams and their ecological significance. Pages 157-177
in L. R. Brown, R. H. Gray, R. H. Hughes, and M. R. Meador,
editors. Effects of urbanization on stream ecosystems.
American Fisheries Society Symposium 47, Bethesda, Maryland.
Urban development modifies the production and delivery of
runoff to streams and the resulting rate, volume, and timing
of streamflow. Given that streamflow demonstrably influences
the structure and composition of lotic communities, we have
identified four hydrologic changes resulting from urban
development that are potentially significant to stream
ecosystems: increased frequency of high flows, redistribution
of water from base flow to storm flow, increased daily
variation in streamflow, and reduction in low flow. Previous
investigations of streamflow patterns and biological
assemblages provide a scale of ecological significance for
each type of streamflow pattern. The scales establish the
magnitude of changes in streamflow patterns that could be
expected to produce biological responses in streams. Long-term
streamflow records from eight streams in urbanizing areas of
the United States and five additional reference streams, where
land use has been relatively stable, were analyzed to assess
if streamflow patterns were modified by urban development to
an extent that a biological response could be expected and
whether climate patterns could account for equivalent
hydrologic variation in the reference streams. Changes in each
type of streamflow pattern were evident in some but not all of
the urban streams and were nearly absent in the reference
streams. Given these results, hydrologic changes are likely
significant to urban stream ecosystems, but the significance
depends on the stream's physiographic context and spatial and
temporal patterns of urban development. In urban streams with
substantially altered hydrology, short-term goals for urban
stream rehabilitation may be limited because of the difficulty
and expense of restoring hydrologic processes in an urban
landscape. The ecological benefits of improving physical
habitat and water quality may be tempered by persistent
effects of altered streamflow. In the end, the hydrologic
effects of urban development must be addressed for restoration
of urban streams.
Available in the DNR Library. Also
available online.
L. 1994. A view of the river. Harvard University Press,
Cambridge, MA.
Increased bankfull discharge. Bankfull frequency increased two
to seven times after urbanization.2
Available at the DNR Library.
Sauer, V.
1983. Flood characteristics of urban watersheds in the
United States. US Geological Survey Water Supply Paper
Increased flood peaks. 50% imperviousness of a watershed can
result in a doubling of the 100-year event.2
A nationwide study of flood magnitude and frequency in urban
areas was made for the purpose of reviewing available
literature, compiling an urban flood data base, and developing
methods of estimating urban floodflow characteristics in
ungaged areas. The literature review contains synopses of 128
recent publications related to urban floodflow. A data base of
269 gaged basins in 56 cities and 31 states, including Hawaii,
contains a wide variety of topographic and climatic
characteristics, land-use variables, indices of urbanization,
and flood-frequency estimates.
T. 1987. Controlling urban runoff: A practical manual for
planning and designing urban best management practices.
Metropolitan Washington Council of Governments. Washington,
D.C., 272 pp.
Increased runoff volume. Parking lot produces 15 times more
runoff than a meadow.2
D., and R. Reynolds. 1982. Effects of urbanization on
baseflow of selected south-shore streams,
Island, NY.
Water Resources Bulletin. 18(5): 797-805.
Decreased baseflow. Two Long Island streams went dry as a
result of urbanization.2
Hydrograph analysis of six streams on the south shore of Long
Island indicates that eastward urbanization during the last
three decades has significantly reduced base flow to streams.
Before urbanization, roughly 95 percent of total annual stream
flow on Long Island was base flow. In urbanized southwestern
Nassau County, storm water sewerage, increased impervious
surface area, and sanitary sewerage have reduced base flow to
20 percent of total stream flow. In an adjacent urbanized but
unsewered area in southeastern Nassau County, base flow has
decreased to 84 percent of total annual stream flow. In
contrast, base flow in two streams in rural areas has remained
virtually constant, averaging roughly 95 percent of total
annual flow throughout the 1955-70 study period. Double-mass
curve analysis of base flow as a percentage of total annual
stream flow indicates that (1) changes in stream flow
characteristics began in the early 1960's in the sewered area
and in the late 1960's in the later urbanized, unsewered area,
and (2) a new equilibrium has been established between the
streams in the sewered area and the new hydrologic
characteristics of their urbanized drainage basins.
Gerard, Bales, J.D., Coles J.F., Giddings, E.M.P., and Zappia,
Humbert. 2003. Use of stage data to characterize hydrologic
conditions in an urbanizing environment. Journal of the
American Water Resources Association 39(6): 1529-1546.
This paper presents the results of a study on the use of
continuous stage data to describe the relation between urban
development and three aspects of hydrologic condition that are
thought to influence stream ecosystems—overall stage
variability, stream flashiness, and the duration of
extreme-stage conditions. This relation is examined using data
from more than 70 watersheds in three contrasting
environmental settings—the humid Northeast (the metropolitan
Boston, Massachusetts, area); the very humid Southeast (the
metropolitan Birmingham, Alabama, area); and the semiarid West
(the metropolitan Salt Lake City, Utah, area). Results from
the Birmingham and Boston studies provide evidence linking
increased urbanization with stream flashiness. Fragmentation
of developed land cover patches appears to ameliorate the
effects of urbanization on overall variability and flashiness.
There was less success in relating urbanization and streamflow
conditions in the Salt Lake City study. A related
investigation of six North Carolina sites with long term
discharge and stage data indicated that hydrologic condition
metrics developed using continuous stage data are comparable
to flow based metrics, particularly for stream flashiness
J.J., Bales, J.D., and Giddings, E.M.P. 2009. Relationship
of stream ecological conditions to simulated hydraulic metrics
across a gradient of basin urbanization, J. N. Am. Benthol.
Soc., 28(4):955–976.
The relationships among urbanization, stream hydraulics, and
aquatic biology were investigated across a gradient of
urbanization in 30 small basins in eastern Wisconsin, USA.
Simulation of hydraulic metrics with 1-dimensional unsteady
flow models was an effective means for mechanistically
coupling the effects of urbanization with stream ecological
conditions (i.e., algae, invertebrates, and fish).
Urbanization, characterized by household, road, and urban land
density, was positively correlated with the lowest shear
stress for 2 adjacent transects in a reach for the low-flow
summer (p < 0.001) and autumn (p < 0.01) periods. Urbanization
also was positively correlated with Reynolds number and %
exposed stream bed during months with moderate to low flows.
Our study demonstrated the value of temporally and spatially
explicit hydraulic models for providing mechanistic insight
into the relationships between hydraulic variables and
biological responses. For example, the positive correlation
between filter-feeding invertebrate richness and minimum
2-transect shear stress observed in our study is consistent
with a higher concentration of water-column particulates
available for filtration. The strength of correlations between
hydraulic and biological metrics is related to the time period
(annual, seasonal, or monthly) considered. The hydraulic
modeling approach, whether based on hourly or daily flow data,
allowed documentation of the effects of a spatially variable
response within a reach, and the results suggest that stream
response to urbanization varies with hydraulic habitat type.
Available online through the DNR Library's subscriptions.
B.L. 1993. The influences of wetland and watershed
morphological characteristics and relationships to wetland
vegetation communities. Master's Thesis, Department of
Civil Engineering, University of Washington, Seattle,
Mean annual water fluctuation was inversely correlated to
plant and amphibian density in urban wetlands. Sharp declines
noted over 10% imperviousness (Seattle). 1
employees should
library to request via interlibrary loan.
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Allen P.
and R. Narramore. 1985. Bedrock controls on stream channel
enlargement with urbanization, North
Water Resources Bulletin. 21(6): 1037-1048.
Channels increase in size. Enlargement ratios in two urban TX
streams ranged from 1.7 to 2.4. 2
Loss due to channel erosion in the Dallas, Texas, area is
estimated to approach one-half million dollars in the last
several years. Hydrogeomorphic analysis of natural and urban
chalk and shale watersheds was performed in the central Texas
area on watersheds ranging in size from 0.5 to 10 square miles
in an effort to more adequately predict channel enlargement
due to urbanization. Chalk watersheds were found to have
greater drainage density, greater channel slope, lower
sinuosity, and greater discharge per unit area than similar
sized shale watersheds under natural conditions. With
subsequent urbanization of the watersheds, chalk channel
enlargement was from 12 to 67 percent greater than shale
channel enlargement for similar sized watersheds. Greater
enlargement in chalk channels is attributed to greater channel
velocities and unit tractive force. Vegetation seems to play a
significant role in influencing channel adjustments to the new
flow regimes brought on by urbanization. Channel response to
urbanization is documented and specific nonstructural
guidelines are proposed which could reduce structural loss
along urban stream channels.
Dartiguenave, C. M., ECLille, I., and D. R. Maidment. 1997.
Water quality master planning for
CRWR Online Report 97-6.
Increased transport of sediment. Bank erosion accounted for up
to 75% of the sediment transport in Austin, TX study.
The goal of this research is the creation of a non-point
source pollution water quality model using a Geographic
Information System. The area chosen for the study is the City
of Austin, which partly overlays the recharge zone of the
Edwards Aquifer. A model based on raster data that takes into
account the presence of the recharge zone was created both in
ArcView and in Arc/Info for mean annual flows and pollutant
loadings. The model is able to perform the following tasks: 1)
compute current pollutant loadings for TSS, BOD, COD, TOC, DP,
TP, NH3, TKN, NO3, TN, Cu, Pb and Zn, 2) compute future
loadings for the year 2040 for the same constituents, 3) model
the effect of located and regional Best Management Practices.
The model was designed so that it could deal with different
sets of input parameters and locations.
Hammer, T.
1972. Stream channel enlargement due to urbanization.
Water Resources Research 8(6): 1530-1540.
Channels increase in size. Enlargement ratios ranged from 0.7
to 3.8 in urban watersheds in PA. 2
Stream channel enlargement occurs in response to the change in
streamflow regimen accompanying urbanization. This empirical
study relates the imputed increase in channel cross‐sectional
area to detailed land use data and other information for 78
small watersheds near Philadelphia. Important differences
between the effects of various types of impervious land use
are observed: large channel enlargement effects are found for
sewered streets and area of major impervious parcels such as
parking lots, and much smaller effects are observed for
unsewered streets and impervious area involving detached
houses. Relatively low channel enlargement effects are
attributed to all types of impervious development less than 4
years old and also to street and house area more than 30 years
old. The influence of impervious development on channel size
is found to be significantly related to topographic
characteristics of the watershed, to the location of
impervious development within the watershed, and to man‐made
drainage alterations. Although the relative importance of
these interactive factors proves difficult to establish, the
most critical determinant of the amount of channel enlargement
resulting from a given level of urbanization appears to be
basin slope.
C., and M. DeAndrea, 1999. Assessing the impact of
urbanization on channel morphology. 2nd International
Conference on Natural Channel Systems. Niagara Falls, OT.
Channels increase in size. Ultimate channel enlargement
correlated with ultimate impervious cover.2
This research developed a methodology for placing a stream in
its proper historical context in terms of channel enlargement.
The MacRae and DeAndrea method utilizes historical and current
data on stream crosssections and land use. Historic
cross-sections are obtained from many sources including prior
geomorphological research, engineering surveys or floodplain
modeling. Current and historic impervious cover estimates are
derived from low altitude aerial photographs taken at
different intervals through the urbanization process. Using a
basic hydraulic model, these data are used to characterize the
pre-development and current cross-sections, and predict the
ultimate cross-sections. An ultimate enlargement curve for 60
channel reaches of alluvial streams in Texas, Maryland and
Vermont is presented in Figure A.2 of "Impervious cover and
land use the the Chesapeake Bay watershed". 2
S. 1997. Contribution of stream channel erosion to sediment
yield from an urbanizing watershed. Science 278:
Increased transport of sediment. Bank erosion accounted for
over 66% of the sediment transport in a CA study.
Stream channel erosion has long been suspected as the major
contributor to long-term sediment yield from urbanizing
watersheds. For San Diego Creek in southern California,
measurements from 1983 to 1993 showed that stream channel
erosion furnished 105 megagrams per year of sediment, or about
two-thirds of the total sediment yield. Thus, because channel
erosion can be a major source of sediment yield from
urbanizing areas, channel stabilization should be a priority
in managing sediment yield.
D., and J. Woodward. 1995. Tracing sources of suspended
sediment in river basins: A case study of the River Culm,
Devon, UK.
Marine and Freshwater Research 46: 324-336.
Increased transport of sediment. Bank erosion in agricultural
regions only accounts for 5 to 20% of sediment load.
Information on the source of the suspended sediment
transported by a river is becoming an increasingly important
requirement in sediment investigations. Such information is
difficult to assemble by means of traditional monitoring
strategies, but the 'fingerprinting' technique offers
considerable potential. The use of composite 'fingerprints' in
combination with a multivariate mixing model can provide a
basis for determining the relative importance of both
individual areas of a catchment and specific source types. The
results of applying this approach to the 276-km² basin of the
River Culm in Devon, UK are presented. A suite of nine
fingerprint properties was employed as a composite
fingerprint, and this permitted the relative contributions of
seven source types to be established. These source types
represented material derived from the surface af cultivated
and pasture areas on each of the three main rock types and
material eroded from channel banks. By collecting samples of
suspended sediment at different times during individual
floods, it was possible to document changes in the relative
contributions of the various sources during each flood in
response to runoff source and travel times. Although the
multivariate fingerprint approach has a number of limitations,
it also has considerable potential as a means of tracing
sources of suspended sediment within a large drainage basin.
Toxicity and Pesticides
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Bryant ,
W.L., Jr., and Goodbred, S.L. 2008. The response of
hydrophobic organics and potential toxicity in streams to
urbanization of watersheds in six metropolitan areas of the
United States. Environmental Monitoring and Assessment
157(1-4): 419-447.
Semipermeable membrane devices (SPMDs) were deployed in
streams along a gradient of urban land-use intensity in and
around six metropolitan areas: Atlanta, Georgia;
Raleigh–Durham, North Carolina; and Denver–Fort Collins,
Colorado, in 2003; and Dallas–Fort Worth, Texas;
Milwaukee–Green Bay, Wisconsin; and Portland, Oregon, in 2004
to examine relations between percent urban land cover in
watersheds and the occurrence, concentrations, and potential
toxicity of hydrophobic compounds. Of the 142 endpoints
measured in SPMD dialysates, 30 were significantly (alpha =
0.05) related to the percent of urban land cover in the
watersheds in at least one metropolitan area. These 30
endpoints included the aggregated measures of the total number
of compounds detected and relative toxicity (Microtox® and
P450RGS assays), in addition to the concentrations of 27
individual hydrophobic compounds. The number of compounds
detected, P450RGS assay values, and the concentrations of
pyrogenic polycyclic aromatic hydrocarbons (PAHs) were
significantly related to percent urban land cover in all six
metropolitan areas. Pentachloroanisole, the most frequently
detected compound, was significantly related to urban land
cover in all metropolitan areas except Dallas–Fort Worth.
Petrogenic PAHs and dibenzofurans were positively related to
percent urban land cover in Atlanta, Raleigh–Durham, Denver,
and Milwaukee–Green Bay. Results for other endpoints were much
more variable. The number of endpoints significantly related
to urban land cover ranged from 6 in Portland to 21
Raleigh–Durham. Based on differences in the number and suite
of endpoints related to urban intensity, these results provide
evidence of differences in factors governing source strength,
transport, and/or fate of hydrophobic compounds in the six
metropolitan areas studied. The most consistent and
significant results were that bioavailable, aryl hydrocarbon
receptor agonists increase in streams as basins become
urbanized. Potential toxicity mediated by this metabolic
pathway is indicated as an important factor in the response of
aquatic biota to urbanization.
L.A. and Nowell, L.H. 2008. Comparison of pesticide
concentrations in streams at low flow in six metropolitan
areas of the United States. Environmental Toxicology and
Chemistry 27(2): 288-298.
To examine the effect of urban development on pesticide
concentrations in streams under low-flow conditions, water
samples were collected at stream sites along an urban land use
gradient in six environmentally heterogeneous metropolitan
areas of the United States. In all six metropolitan areas,
total insecticide concentrations generally increased
significantly as urban land cover in the basin increased,
regardless of whether the background land cover in the basins
was agricultural, forested, or shrub land. In contrast, the
response of total herbicide concentrations to urbanization
varied with the environmental setting. In the three
metropolitan areas with predominantly forested background land
cover (Raleigh-Durham, NC, USA; Atlanta, GA, USA; Portland,
OR, USA), total herbicide concentrations increased
significantly with increasing urban land cover. In contrast,
total herbicide concentrations were not significantly related
to urban land cover in the three remaining metropolitan areas,
where total herbicide concentrations appeared to be strongly
influenced by agricultural as well as urban sources
(Milwaukee-Green Bay, WI, USA; Dallas-Fort Worth, TX, USA), or
by factors not measured in the present study, such as water
management (Denver, CO, USA). Pesticide concentrations rarely
exceeded benchmarks for protection of aquatic life, although
these low-flow concentrations are likely to be lower than at
other times, such as during peak pesticide-use periods, storm
events, or irrigation discharge. Normalization of pesticide
concentrations by the pesticide toxicity index -- an index of
relative potential toxicity -- for fish and cladocerans
indicated that the pesticides detected at the highest
concentrations (herbicides in five of the six metropolitan
areas) were not necessarily the pesticides with the greatest
potential to adversely affect aquatic life (typically
insecticides such as carbaryl, chlorpyrifos, diazinon, and
and Chloride
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Morgan, R.
P., K. M. Kline, and S. F. Cushman. 2007. Relationships
among nutrients, chloride and biological indices in urban
Maryland streams.
Urban Ecosystems 10:153-166.
Using a spatially extensive urban database constructed from
the Maryland Biological Stream Survey (MBSS), we describe the
relationships of nutrients in small-order streams to eight
defined categories of percent catchment urbanization,
correlations between chloride and conductivity in urban
streams, and relationships between nutrients and chloride with
two Maryland-specific indices of biotic integrity for benthic
macroinvertebrates and fish assemblages. Stream nutrients
become elevated with increasing percent catchment
urbanization, followed by increases in all four measured
nitrogen species and total phosphorus at catchment
urbanization levels greater than 10%. There was a strong
collinear relationship (r 2 = 0.90)
between chloride and conductivity (trimeans) across all eight
urbanization classes, where Cl (mg/L) = −0.397 + 0.188*conductivity
(μS/cm). Critical values for all water quality parameters with
the two Maryland biological indices were derived using
quantile regression, with significant regressions developed
for 11 of 16 water quality parameters and the two biotic
indices. For nitrate (NO3-N), the critical thresholds between
fair and poor stream quality for the two Maryland biological
indices were 0.83 mg/L (benthic macroinvertebrate assemblages)
and 0.86 mg/L (fish assemblages). Increasing stream nutrient
and chloride levels, associated with widespread catchment
urbanization intensity, now affect many small streams in
Maryland, with implications for decreasing water quality in
major tributaries and the Chesapeake Bay.
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S. S., P. M. Groffman, G. E. Likens, K. T. Belt, W. P. Stack,
V. B. Kelly, L. E. Band, and G. T. Fisher. 2005.
Increased salinization of fresh water in the northeastern
United States.
Proceedings of the National Academy of Sciences
Chloride concentrations are increasing at a rate that
threatens the availability of fresh water in the northeastern
United States. Increases in roadways and deicer use are now
salinizing fresh waters, degrading habitat for aquatic
organisms, and impacting large supplies of drinking water for
humans throughout the region. We observed chloride
concentrations of up to 25% of the concentration of seawater
in streams of Maryland, New York, and New Hampshire during
winters, and chloride concentrations remaining up to 100 times
greater than unimpacted forest streams during summers. Mean
annual chloride concentration increased as a function of
impervious surface and exceeded tolerance for freshwater life
in suburban and urban watersheds. Our analysis shows that if
salinity were to continue to increase at its present rate due
to changes in impervious surface coverage and current
management practices, many surface waters in the northeastern
United States would not be potable for human consumption and
would become toxic to freshwater life within the next century.
Available online.
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Mallin, M.
A., K. E. Williams, E. C. Esham, and R. P. Lowe. 2000.
Effect of human development on bacteriological water quality
in coastal watersheds. Ecological Applications
Human development along the land–seawater interface is
considered to have significant environmental consequences.
Development can also pose an increased human health risk. In a
rapidly developing coastal region we investigated this
phenomenon throughout a series of five estuarine watersheds,
each of which differed in both the amount and type of
anthropogenic development. Over a four-year period we analyzed
the abundance and distribution of the enteric pathogen
indicator microbes, fecal coliform bacteria and Escherichia
coli. We also examined how these indicator microbes were
related to physical and chemical water quality parameters and
to demographic and land use factors throughout this system of
coastal creeks. Within all creeks, there was a spatial pattern
of decreasing enteric bacteria away from upstream areas, and
both fecal coliform and E. coli abundance were inversely
correlated with salinity. Turbidity was positively correlated
with enteric bacterial abundance. Enteric bacterial abundance
was strongly correlated with nitrate and weakly correlated
with orthophosphate concentrations. Neither fecal coliforms
nor E. coli displayed consistent temporal abundance patterns.
Regardless of salinity, average estuarine fecal coliform
abundance differed greatly among the five systems. An analysis
of demographic and land use factors demonstrated that fecal
coliform abundance was significantly correlated with watershed
population, and even more strongly correlated with the
percentage of developed land within the watershed. However,
the most important anthropogenic factor associated with fecal
coliform abundance was percentage watershed-impervious surface
coverage, which consists of roofs, roads, driveways,
sidewalks, and parking lots. These surfaces serve to
concentrate and convey storm-water-borne pollutants to
downstream receiving waters. Linear regression analysis
indicated that percentage watershed-impervious surface area
alone could explain 95% of the variability in average
estuarine fecal coliform abundance. Thus, in urbanizing
coastal areas waterborne health risks can likely be reduced by
environmentally sound land use planning and development that
minimizes the use of impervious surface area, while maximizing
the passive water treatment function of natural and
constructed wetlands, grassy swales, and other "green" areas.
The watershed approach used in our study demonstrates that the
land–water interface is not restricted to obvious shoreline
areas, but is influenced by and connected with landscape
factors throughout the watershed.
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Booth, D.
B., Montgomery, D.R., and J. Bethel. 1996. Large woody
debris in the urban streams of the
Pp.In: Effects of Watershed Development and Management on
Aquatic Ecosystems. Roesner, L.A. (ed.), Proceedings of ASCE/Engineering
Foundation Conference. August, 1996. Snowbird, UT.
is a decrease in the quantity of large woody debris found in
urban streams at around 10% impervious cover (Washington).
Booth, D.
1991. Urbanization and the natural drainage system—impacts,
solutions, and prognoses. Northwest Environmental Journal
Channel stability and fish habitat quality declined rapidly
after 10% imperviousness (Seattle). 1
Drainage systems consist of all of the elements of the
landscape through which or over which water travels. These
elements include the soil and the vegetation that grows on it,
the geologic materials underlying that soil, the stream
channels that carry water on the surface, and the zones where
water is held in the soil and moves beneath the surface. Also
included are any constructed elements, including pipes and
culverts, cleared and compacted land surfaces, and pavement
and other impervious surfaces that are not able to absorb
water at all. A landscape can be divided into individual
drainage basins, each of which contains all the elements of a
drainage system that contribute water to one particular stream
R.R., Booth, D. B., Azous, A., and C. W. May.1996.
Watershed determinants of ecosystem functioning. In:
Effects of Watershed Development and Management on Aquatic
Ecosystems. Roesner, L.A. (ed.), Proceedings of ASCE/Engineering
Foundation Conference. August, 1996. Snowbird, UT.
Embeddedness. Interstitial spaces between substrate fill with
increasing watershed imperviousness. 2
J.S. 1982. Effects of urbanization on a lowland stream in
urban Washington. PhD Dissertation. University of
Changes in stream features. Altered pool/riffle sequence with
urbanization. 2
The effects of nonpoint source pollution due to urbanization
and stormwater runoff on the structure and function of an
urban stream in western Washington, Kelsey Creek, were
investigated in comparison to a nearby, control stream, Bear
Creek. The results of the study indicated that changes in
stream hydrology and geomorphology were the critical agents in
causing alterations in the ecological structure of the stream.
Important changes in the hydrologic regime included increased
peak flows, decreased minimum flows and an acceleration in
hydrograph rise and fall. Constriction of the channel resulted
in a substantial reduction in stream surface area, the space
available for biotic activity. The number and size of debris
dams, which provide storage sites and protected habitat, were
greatly diminished. Higher stream power resulted in increased
fluvial transport, channel erosion and bed instability.
Scott, J.,
Steward, C., and Q. Stober. 1986. Effects of urban
development on fish population dynamics in
Creek, Washington.
Transactions of the American Fisheries Society. 115:555-567.
Changes in stream features. Loss of habitat diversity. 2
A 30-month study of the comparative dynamics of the fish
populations inhabiting Kelsey Creek, located in the City of
Bellevue, Washington, and a nearby pristine control stream
suggest that urban development has resulted in a restructuring
of the fish community. Environmental perturbations, including
habitat alteration, increased nutrient loading, and
degradation of the intragravel environment appeared to have a
greater impact on coho salmon Oncorhynchus kisutch and
nonsalmonid fish species than on cutthroat trout Salmo clarki.
Although the total biomass (g/m2) of fish in each stream was
similar, its composition differed markedly. Ages 0 and I
cutthroat trout were the majority of the fish community
inhabiting Kelsey Creek, whereas the control stream supported
a diverse assemblage of salmonids of various ages and numerous
nonsalmonids. The rapid growth and greater biomass of
salmonids in Kelsey Creek (a 2-year mean of 3.51 g/m2 versus
2.03 g/m2 in the control stream) resulted in a total annual
net production of these species of 1.6 to 3.3 times that of
the control stream (a 2-year mean of 7.6 g/m2 versus 3.5 g/m2
in the control stream). Marking and outmigrant studies
indicated that environmental disruptions in the urban stream
do not result in the displacement of the salmonid inhabitants.
B., Lomnicky, G., Hughes, R., and R. Novitzki. 1996. An
ecosystem approach to salmonid conservation.
TR-401-96-6057. ManTech Environmental Research Services
Corporation, Corvallis, OR.
Large woody debris. Important for habitat diversity and
anadramous fish. 2
Short, T.M.,
Giddings, E.M.P., Zappia, H., Coles, J.F. 2005.
Urbanization effects on habitat characteristics of streams in
Boston, Massachusetts, Birmingham, Alabama, and Salt Lake
City, Utah. In Brown, L.R., Gray, R.H., Hughes, R.M., and
Meador, M.R., eds., Effects of urbanization on stream
ecosystems. American Fisheries Society, Symposium 47,
Bethesda, Maryland, p. 317-332.
Relations between stream habitat and urban land-use intensity
were examined in 90 stream reaches located in or near the
metropolitan areas of Salt Lake City, Utah (SLC); Birmingham,
Alabama (BIR); and Boston, Massachusetts (BOS). Urban
intensity was based on a multi-metric index (urban intensity
index or UII) that included measures of land cover,
socioeconomic organization, and urban infrastructure.
Twenty-eight physical variables describing channel morphology,
hydraulic properties, and streambed conditions were examined.
None of the habitat variables was significantly correlated
with urbanization intensity in all three study areas.
Urbanization effects on stream habitat were less apparent for
streams in SLC and BIR, owing to the strong influence of basin
slope (SLC) and drought conditions (BIR) on local flow
regimes. Streamflow in the BOS study area was not unduly
influenced by similar conditions of climate and physiography,
and habitat conditions in these streams were more responsive
to urbanization. Urbanization in BOS contributed to higher
discharge, channel deepening, and increased loading of
fine-grained particles to stream channels. The modifying
influence of basin slope and climate on hydrology of streams
in SLC and BIR limited our ability to effectively compare
habitat responses among different urban settings and identify
common responses that might be of interest to restoration or
water management programs. Successful application of land-use
models such as the UII to compare urbanization effects on
stream habitat in different environmental settings must
account for inherent differences in natural and anthropogenic
factors affecting stream hydrology and geomorphology. The
challenge to future management of urban development is to
further quantify these differences by building upon existing
models, and ultimately develop a broader understanding of
urbanization effects on aquatic ecosystems.
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Galli, J.
1991. Thermal impacts associated with urbanization and
stormwater management best management practices.
Metropolitan Washington Council of Governments, Maryland
Department of Environment, Washington, D.C.
Temperature. Increase in stream temperatures five to twelve
degrees Fahrenheit with urbanization (check figures)
Available online. Also
available at the DNR Library.
Channel Impacts
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Dunne T.,
and L. Leopold. 1978. Water in environmental planning.
W.H. Freeman and Company, New York, NY.
Reduction in 1st Order Streams. Replacement by
storm drains and pipes increases erosion rate downstream.
Metropolitan Washington Council of Governments (MWCOG), 1992.
Watershed restoration sourcebook. Department of
Environmental Programs, MWCOG, Washington, DC.
Fish blockages. Fish blockages caused by bridges and culverts.
Available in DNR Library.
Sauer, V.
1983. Flood characteristics of urban watersheds in the
United States. US Geological Survey Water Supply Paper
Channelization and hardening of stream channels. Increased
instream velocities often leading to increased erosion rates
downstream. 2
Habitat Integrity
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Black and
Veatch. 1994. Longwell Branch Restoration-Feasibility Study.
Vol. 1. Carroll County, MD Office of Environmental Services.
220 p.
Key finding:
Fish, insect, and habitat scores were all ranked as poor in 5
subwatersheds that were greater than 30% imperviousness (Maryland).
Boward, D.,
Kayzak, P., Stranko, S., Hurd, M., and T. Prochaska. 1999.
From the mountains to the sea: The state of
freshwater streams.
EPA 903-R-99-023. Maryland Department of Natural Resources,
Monitoring and Non-tidal Assessment Division, Annapolis,
Key finding:
Several sensitive species of amphibians were not found at
impervious levels greater than 3%. Only a few intolerant
species were found at impervious levels greater than 25%.
Brook trout were not found in watersheds with greater than 2%
imperviousness (Maryland). 2
In The Mountains to the Sea: the State of
Maryland's Freshwater Streams, the Maryland Department of Natural
Resources (MDDNR) provides information on the status of the
biological community in the state's streams. The relationship
between land use and impervious cover is examined for fish,
macroinvertebrates, amphibians and other sensitive species.
Above a 15% impervious cover threshold, streams were found to
have a poor or fair biological condition. Sensitive species,
such as the native brook trout, were shown to disappear beyond
two percent impervious cover. Other relationships between land
use and stream water quality are covered in the document as
well. 2
Available online.
Coles, J.F.,
Cuffney, T.F., McMahon, G., and Rosiu, C.J. 2010. Judging a
brook by its cover - the relation between ecological condition
of a stream and urban land cover in New England.
Northeastern Naturalist 17(1): 29-48.
The US Geological Survey conducted an urban land-use study in
the New England Coastal Basins (NECB) area during 2001 to
determine how urbanization relates to changes in the
ecological condition of streams. Thirty sites were selected
that differed in their level of watershed development (low to
high). An urban intensity value was calculated for each site
from 24 landscape variables. Together, these 30 values
represented a gradient of urban intensity. Among various
biological, chemical, and physical factors surveyed at each
site, benthic invertebrate assemblages were sampled from
stream riffles and also from multiple habitats along the
length of the sampling reach. We use some of the NECB data to
derive a four-variable urbanintensity index (NECB-UII), where
each variable represents a distinct component of urbanization:
increasing human presence, expanding infrastructure, landscape
development, and riparian vegetation loss. Using the NECB-UII
as a characterization of urbanization, we describe how
landscape fragmentation occurs with urbanization and how
changes in the invertebrate assemblages, represented by
metrics of ecological condition, are related to urbanization.
Metrics with a strong linear response included EPT taxa
richness, percentage richness of non-insect taxa, and
pollution-tolerance values. Additionally, we describe how
these relations can help in estimating the expected condition
of a stream for its level of urbanization, thereby
establishing a baseline for evaluating possible affects from
specific point-source stressors.
Crawford, J.,
and D. Lenat. 1989. Effects of land use on water quality
and the biota of three streams in the
Province of
North Carolina.
USGS. Water Resources Investigations Report 89-4007. Raleigh,
NC, 67 pp.
Key finding: A comparison
of three stream types found urban streams had lowest diversity
and richness. Urban streams had substantially lower EPT scores
(22% vs 5% as the number of all taxa, 65% vs 10% as a percent
abundance) and IBI scores in the poor range (North Carolina).
Three small streams in North Carolina 's northern Piedmont
were studied to compare the effects of land use in their
watersheds on water quality characteristics and aquatic biota.
Devil 's Cradle Creek (agricultural watershed) had more than
two times the sediment yield of Smith Creek (forested
watershed) (0.34 tons/acre compared to 0.13 tons/acre), and
Marsh Creek (urban watershed) had more than four times the
yield of Smith Creek (0.59 tons/acre). Concentrations of
nutrients were consistently highest in Devil 's Craddle Creek.
Concentrations of total copper, iron, and lead in samples from
each of the three streams at times exceeded State water
quality standards as did concentrations of total zinc in
samples from both Smith and Marsh Creeks. Successively lower
aquatic invertebrate taxa richness was found in the forested,
the agricultural, and the urban watershed streams.
Invertebrate biota in Smith Creek was dominated by insects,
such as Ephemeroptera, that are intolerant to stress from
pollution, whereas Devil 's Cradle Creek was dominated by the
more tolerant Diptera, and Marsh Creek was dominated by the
most pollution-tolerant group, the Oligochaeta. Fish
communities in the forested and agricultural watershed streams
were characterized by more species and more individuals of
each species, relative to a limited community in urban Marsh
Creek. Three independent variables closely linked to land
use--suspended-sediment yield, suspended-sediment load, and
total lead concentrations in stream water--are inversely
associated with the biological communities of the streams.
DeVivo, J.C.,
Couch, C.A.,
and B. J. Freeman. 1997. Use of Preliminary Index of Biotic
Integrity in Urban Streams around
Pp. 40-43 in 1997 Georgia Water Resources Conference.
Key finding:
As watershed population density increased, there was a
negative impact on urban fish and habitat. Urban stream IBI
scores were inversely related to watershed population density,
and once density exceeded four persons per acre, urban streams
were consistently rated as very poor (Atlanta).
Klein, R.
1979. Urbanization and stream quality impairment.
American Water Resources Association. Water Resources
Bulletin. 15(4): 948-963.
Macroinvertebrate and fish diversity declines
rapidly after 10% imperviousness (Maryland).
A study was conducted in the Piedmont province of Maryland to
determine if a relationship exists between stream quality and
the extent of watershed urbanization. During the first phase
of the study 27 small watersheds, having similar
characteristics but varied according to land use, were
investigated. Using these controlled conditions, eliminating
as many interferences as possible, this first phase was
intended to determine if a definite relationship did exist
between the two factors. Finding that the first phase was
successful the second was initiated which consisted of a
comparison of biological sampling data, from other studies,
with degree of watershed urbanization. The purpose of this
second phase was to ascertain if the relationship between
degrees of urbanization and decline in stream quality was
linear as watershed area increased and in streams spread
throughout the Maryland Piedmont. The principal finding of
this study was that stream quality impairment is first
evidenced when watershed imperviousness reaches 12%, but does
not become severe until imperviousness reaches 30%.
Masterson, J.
P., and R. T. Bannerman. 1994. Impacts of stormwater runoff
on urban streams in
Milwaukee County,
Wisconsin. National Symposium on Water Quality. American Water
Resources Association.
Key finding:
A study of five urban streams found that as land use shifted
from rural to urban, fish and macroinvertebrate diversity
decreased (Wisconsin).
T. and J. Galli. 1992. Environmental impacts of stormwater
ponds. In Watershed Restoration SourceBook. Anacostia
Restoration Team. Metropolitan Washington Council of
Governments. Washington, DC. 242 p.
Fish diversity declined sharply with increasing
imperviousness, loss in diversity began at 10% to 12%
imperviousness. Insect diversity metrics in 24 subwatersheds
shifted from good to poor over 15% imperviousness (Maryland).1
R.J. 1988. Modification and assessment of an index of
biotic integrity to quantify stream quality in southern
Ontario. Canadian Journal of Fisheries and Aquatic
Sciences 45:492–501.
Strong negative relationship between biotic integrity and
increasing urban land use/riparian condition at 209 stream
sites. Degradation begins at about 10% imperviousness
(Ontario). 1
A multivariate measure of stream quality, the Index of Biotic
Integrity (IBI), was adapted to southern Ontario and
calibrated to watershed land use on a variety of spatial
scales. The fish fauna at 209 stream locations on 10
watersheds near Toronto, Ontario, was sampled with a backpack
electrofisher in the summers of 1984 and 1985 to provide
biological information for the IBI. Watershed urbanization,
forest cover, and riparian forest were measured from 1:50,000
scale topographic maps and related to IBI estimates by linear
Wang, L.,
Lyons, J., Kanehl, P., and R. Gatti. 1997. Influences of
watershed land use on habitat quality and biotic integrity in
Fisheries 22 (6) :6-11.
Key finding:
Amount of urban land use upstream of sample sites had a strong
negative relationship with biotic integrity, and there
appeared to be a threshold between 10-20% urban land use where
IBI scores declined dramatically. Watersheds above 20% urban
land invariably had scores less than 30 (poor to very poor) (Wisconsin).
We analyzed relationships between watershed land use and
habitat quality, and between watershed land use and biotic
integrity for 134 sites on 103 streams located throughout
Wisconsin. Habitat quality and index of biotic integrity (IBI)
scores were significantly positively correlated with the
amount of forested land and negatively correlated with the
amount of agricultural land in the entire watershed and in a
100-m-wide buffer along the stream. Correlations were
generally stronger for the entire watershed than for the
buffer. Relationships between forested land and habitat and
biotic integrity were linear, although there were several
outlying sites with lower-than-expected IBI scores.
Relationships with agricultural land use were more complex,
with an obvious decline in habitat quality and IBI scores
apparent only when agricultural land use exceeded 50%. Even
when agricultural land use exceeded 80%, some sites maintained
relatively good habitat quality and biotic integrity. These
"good" sites tended to have relatively high gradients and
rocky substrates, and had not been channelized. High urban
land use was strongly associated with poor biotic integrity
and was weakly but significantly associated with poor habitat
quality. There appeared to be a threshold value of
urbanization between 10% and 20% beyond which IBI scores were
consistently very low. Overall, watershed land uses had strong
effects on habitat quality and biotic integrity in Wisconsin
Yoder, C.,
and R. Miltner. 2000. Using biological criteria to assess
and classify urban streams and develop improved landscape
indicators. In Proceedings of the National Conference on
Tools for Urban Water Resource Management & Protection:
Published by the US Environmental Protection Agency, Office of
Research and Development, Washington, D.C.
Key finding:
For watersheds smaller than 100 mi2 a significant drop in
IBI scores occurred at around 15% imperviousness (Ohio).2
C.O., R. Miltner, and D. White. 1999. Assessing the status
of aquatic life designated uses in urban and suburban
watershed. In R. Kirschner (Ed.). National Conference on
Retrofit Opportunities for Water Resource Protection in Urban
Environments. EPA/625/R-99/002.
Yoder, C.
1991. The integrated biosurvey as a tool for evaluation of
aquatic life use attainment and impartment in
surface waters.
In Biological Criteria: Research and Regulation, Proceedings
of a Symposium, 12-13 December 1990, Arlington, VA, U.S. EPA,
Office of Water, Washington, DC, EPA-440/5-91-005:110.
100% of 40 urban sites sampled had fair to very poor index of
biotic integrity scores (Ohio). 1
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Benke, A.E.,
Willeke, F.P., and D. Stites. 1981. Effects of urbanization
on stream ecosystems. Completion Report Project No.
A-055-GA. Office of Water Research and Technology. US Dept. of
Negative relationship between number of aquatic insect
species and urbanization in 21 streams (Atlanta).1
The effects of urbanization on 21 stream ecosystems were
studied in the Atlanta area in 1-3 sq mile watersheds varying
from 3-100 % green space, from 0-98% residential-commercial,
and with house densities from 0-941 sq miles. The primary
index of stream quality was community composition of aquatic
macroinvertebrates. The streams were in a single area where
physico-chemical conditions and composition of
macroinvertebrates should be very similar under natural
conditions. While there were widely-varying degrees of
urbanization, pollution (as indicated by standard water
quality measures) was not at all obvious, and differentiation
of stream communities was more subtle than is often
encountered in studies of gross pollution. A significant
relationship was found between urbanization and number of
species/families (but not with species/family diversity,
indicating less utility for a diversity index). Hence,
identifying macroinvertebrates to the family level is
sufficient in assessing differing degrees of stress in
streams. Cluster analysis distinguished three major groups of
streams: clean, intermediate, and degraded. High residential
land use, low levels of green space, and high house densities
were associated with degraded streams. (Zielinski-MAXIMA)
Cuffney, T.F., Brightbill, R.A., May, J.T., and Waite, IR.
2010. Responses of benthic macroinvertebrates to
environmental changes associated with urbanization in nine
metropolitan areas. Ecological Applications 20(5):
Abstract: Responses of benthic macroinvertebrates along
gradients of urban intensity were investigated in nine
metropolitan areas across the United States. Invertebrate
assemblages in metropolitan areas where forests or shrublands
were being converted to urban land were strongly related to
urban intensity. In metropolitan areas where agriculture and
grazing lands were being converted to urban land, invertebrate
assemblages showed much weaker or nonsignificant relations
with urban intensity because sites with low urban intensity
were already degraded by agriculture. Ordination scores, the
number of EPT taxa, and the mean pollution-tolerance value of
organisms at a site were the best indicators of changes in
assemblage condition. Diversity indices, functional groups,
behavior, and dominance metrics were not good indicators of
urbanization. Richness metrics were better indicators of urban
effects than were abundance metrics, and qualitative samples
collected from multiple habitats gave similar results to those
of single habitat quantitative samples (riffles or woody
snags) in all metropolitan areas. Changes in urban intensity
were strongly correlated with a set of landscape variables
that was consistent across all metropolitan areas. In
contrast, the instream environmental variables that were
strongly correlated with urbanization and invertebrate
responses varied among metropolitan areas. The natural
environmental setting determined the biological, chemical, and
physical instream conditions upon which urbanization acts and
dictated the differences in responses to urbanization among
metropolitan areas. Threshold analysis showed little evidence
for an initial period of resistance to urbanization. Instead,
assemblages were degraded at very low levels of urbanization,
and response rates were either similar across the gradient or
higher at low levels of urbanization. Levels of impervious
cover that have been suggested as protective of streams
(5–10%) were associated with significant assemblage
degradation and were not protective.
Available online.
Abstract: Responses of benthic macroinvertebrates along
gradients of urban intensity were investigated in nine
metropolitan areas across the United States. Invertebrate
assemblages in metropolitan areas where forests or shrublands
were being converted to urban land were strongly related to
urban intensity. In metropolitan areas where agriculture and
grazing lands were being converted to urban land, invertebrate
assemblages showed much weaker or nonsignificant relations
with urban intensity because sites with low urban intensity
were already degraded by agriculture. Ordination scores, the
number of EPT taxa, and the mean pollution-tolerance value of
organisms at a site were the best indicators of changes in
assemblage condition. Diversity indices, functional groups,
behavior, and dominance metrics were not good indicators of
urbanization. Richness metrics were better indicators of urban
effects than were abundance metrics, and qualitative samples
collected from multiple habitats gave similar results to those
of single habitat quantitative samples (riffles or woody
snags) in all metropolitan areas. Changes in urban intensity
were strongly correlated with a set of landscape variables
that was consistent across all metropolitan areas. In
contrast, the instream environmental variables that were
strongly correlated with urbanization and invertebrate
responses varied among metropolitan areas. The natural
environmental setting determined the biological, chemical, and
physical instream conditions upon which urbanization acts and
dictated the differences in responses to urbanization among
metropolitan areas. Threshold analysis showed little evidence
for an initial period of resistance to urbanization. Instead,
assemblages were degraded at very low levels of urbanization,
and response rates were either similar across the gradient or
higher at low levels of urbanization. Levels of impervious
cover that have been suggested as protective of streams
(5–10%) were associated with significant assemblage
degradation and were not protective.
T.F., Zappia, H., Giddings, E.M.P., and Coles. J.F. 2005.
Effects of urbanization on benthic macroinvertebrate
assemblages in contrasting environmental settings: Boston,
Massachusetts; Birmingham, Alabama; and Salt Lake City, Utah.
In Brown, L.R., Gray, R.H., Hughes, R.M., and Meador, M.R.,
eds., Effects of urbanization on stream ecosystems, American
Fisheries Society, Symposium 47, Bethesda, Maryland, p.
Responses of invertebrate assemblages along gradients of urban
intensity were examined in three metropolitan areas with
contrasting climates and topography (Boston, Massachusetts;
Birmingham, Alabama; Salt Lake City, Utah). Urban gradients
were defined using an urban intensity index (UII) derived from
basin-scale population, infrastructure, land-use, land-cover,
and socioeconomic characteristics. Responses based on
assemblage metrics, indices of biotic integrity (B-IBI), and
ordinations were readily detected in all three urban areas and
many responses could be accurately predicted simply using
regional UIIs. Responses to UII were linear and did not
indicate any initial resistance to urbanization. Richness
metrics were better indicators of urbanization than were
density metrics. Metrics that were good indicators were
specific to each study except for a richness based tolerance
metric (TOLr) and one B-IBI. Tolerances to urbanization were
derived for 205 taxa. These tolerances differed among studies
and with published tolerance values, but provided similar
characterizations of site conditions. Basin-scale land-use
changes were the most important variables for explaining
invertebrate responses to urbanization. Some chemical and
instream physical habitat variables were important in
individual studies, but not among studies. Optimizing the
study design to detect basin-scale effects may have reduced
the ability to detect local-scale effects.
Garie, H.
and A. McIntosh. 1986. Distribution of benthic
macroinvertebrates in streams exposed to urban runoff.
Water Resources Bulletin 22: 447-458.
Drop in aquatic insect taxa from 13 to 4 noted in urban
streams (New Jersey). 1
A study of benthic macroinvertebrate community composition was
conducted at eight sites along Shabakunk Creek, a small stream
in Mercer County, New Jersey, which receives urban runoff. The
relationship between changes in substrate composition and the
nature of the benthic macroinvertebrate community has been
examined. Organisms were collected seasonally from natural
substrates in riffles. Attempts to employ artificial
substrates for invertebrate collection proved unsuccessful, as
the population on the samplers was not representative of that
in the stream bed. Number of total benthic macroinvertebrate
taxa collected declined from 13 in relatively undeveloped
upstream areas to four below heavily developed areas, while
population density decreased simultaneously in the same areas.
Periphyton samples collected from natural substrates were
analyzed for selected heavy metals. Significantly higher heavy
metal concentrations are reported from substrates sampled
below heavily developed areas, and changes in these values are
discussed with regard to changes in benthic macroinvertebrate
Hicks, A.L.,
and J.S. Larson. 1997. The impact of urban stormwater
runoff on freshwater wetlands and the role of aquatic
invertebrate bioassessment. The Environment Institute,
University of Massachusetts. Amherst, MA.
Key finding:
Significant declines in various indicators of wetland aquatic
macroinvertebrate community health were observed as impervious
cover increased to 8-9% (Connecticut).
Access: DNR employees should
library to request via interlibrary loan.
Horner, R.R.,
Booth, D. B., Azous, A., and C. W. May. 1996. Watershed
determinants of ecosystem functioning. In: Effects of
Watershed Development and Management on Aquatic Ecosystems.
Roesner, L.A. (ed.), Proceedings of ASCE/Engineering
Foundation Conference. August, 1996. Snowbird, UT.
Key finding:
Biological health of the macroinvertebrate community declined
as imperviousness increased. It appears that stormwater
treatment practices (STPs) are capable of mitigating some of
these impacts within the 12-23% I range. Above this range,
declines in biological condition continue at a similar rate to
sites without STPs. Evidence suggests that if high levels of
riparian forest or wetlands >30m are saved, a doubling in
total impervious area could occur while still maintaining high
B-IBI and fish ratio scores. Steepest decline of biological
functioning after 6% imperviousness. There was a steady
decline, with approx 50% of initial biotic integrity at 45%
impervious area. (Puget Sound, Washington).
Jones, R.
and C. Clark. 1987. Impact of watershed urbanization on
stream insect communities. Water Resources Bulletin 23(6):
Key finding:
Urban streams had sharply lower diversity of aquatic insects
when human population density exceeded 4 persons per acre
(estimated 15% to 25% impervious cover.) (Northern Virginia).
The impact of urbanization on stream insect communities was
determined by sampling 22 sites in northern Virginia
representing a range of human population densities. Watershed
development had little effect on the total insect numbers
(no./sq m), but shifted the taxonomic composition markedly.
Relative abundance of Diptera (mainly chironomids) increased
at more highly urbanized sites, while most other insect orders
including Ephemeroptera (mayflies), Coleoptera (beetles),
Megaloptera (dobsonflies), and Plecoptera (stoneflies)
decreased. Trichoptera (caddisflies) exhibited a variable
response. Genus diversity and richness (number of genera) were
significantly higher in less urbanized streams. Two genera of
chironomids were positively correlated with increased
urbanization, while 14 other genera (scattered through several
orders) were negatively related to human population density.
Principal components analysis demonstrated a gradient from
more urbanized to less urbanized stations based on generic and
order level biological data. Results indicate that watershed
urbanization has a major impact on benthic insect communities
even in the absence of point source discharges.
Moore, A.
A., and M. A. Palmer. 2005. Invertebrate biodiversity in
agricultural and urban headwater streams: implications for
conservation and management. Ecological Applications
The urbanization of agricultural lands is currently one of the
dominant patterns of land use change in developed countries.
In the United States and parts of Europe, this has led to the
implementation of agricultural land preservation programs and
riparian protection and replanting efforts along urban
streams. The ecological benefits of such programs for the
conservation of freshwater biodiversity have yet to be fully
explored. We designed a study to investigate the patterns of
stream macroinvertebrate community structure along a gradient
of agriculture to urban development, and the patterns among
urban streams that vary in the amount of intact riparian
buffer. In 2001 and 2002, we sampled the 29 small headwater
streams comprising the outlying tributaries of four watersheds
just north of Washington, D.C., in Montgomery County,
Maryland, USA. This region has had dramatic urban development
over the last 50 years, yet significant efforts have been made
to maintain riparian buffers and promote preservation of
agricultural land.
Macroinvertebrate richness was strongly related to land use,
with agricultural streams exhibiting the highest
macroinvertebrate diversity. Taxa richness was related
negatively and linearly (no statistical threshold) to the
amount of impervious surface cover. For the urban streams,
there was a strong positive relationship between invertebrate
diversity and riparian forest cover. Urban streams with high
amounts of intact riparian forest exhibited biodiversity
levels more comparable to less urban areas despite high
amounts of impervious cover in their catchments. The
agricultural headwater streams in this study were not only
more diverse than the urban headwaters, but their levels of
macroinvertebrate diversity were high compared to other
published estimates for agricultural streams. These higher
richness values may be due to widespread use of "best
management practices" (BMPs), including no-till farming and
the implementation of woody and herbaceous riparian buffers,
which may alleviate many acute stressors caused by
cultivation. These findings suggest that, if managed properly,
the preservation of agricultural land from development may
help conserve stream invertebrate biodiversity, and that
maintenance of riparian forests even in highly urbanized
watersheds may help alleviate ecological disturbances that
might otherwise limit macroinvertebrate survival.
E. and M. Perkins. 1986. The use of benthic invertebrate
data for evaluating impacts of urban runoff. Hydrobiologia.
139: 13-22.
Macroinvertebrate community shifted to chironomid,
oligochaetes, and amphipod species tolerant of unstable
conditions (Seattle). 1
The benthic macroinvertebrate population of a stream in an
urbanized watershed was compared to the benthos in a rural
stream. Using buried samplers, no significant difference
between streams was found in total numbers of invertebrates,
indicating no long term loss of colonization potential in the
urban stream. Classifying the benthos in functional family
groupings (based on Cummins, 1973) showed the rural stream to
have nearly twice the functional diversity of the urban
stream. The benthos of the urban stream was dominated by a few
groups of invertebrates which could adapt to the erosional/depositional
nature of the substrate and could utilize transient, low
quality food sources. The density of invertebrates was
adequate to support a coho salmon and cutthroat trout
population in the urban stream. Apparently, the salmonids feed
on available benthos and do not select specific benthic
trophic groups. An evaluation of six similarity coefficients
using cluster analysis showed that only the Canberra Metric
index was able to represent the raw data according to known
data associations.
employees should
library to request via interlibrary loan.
E., J.Maxted, G. Curtis, and D. Carter. 1995. Watershed
protection using an integrated approach. In Stormwater
NPDES-related Monitoring Needs. Engineering Foundation.
Crested Butte, Colorado. August 7–12, 1994. American Society
of Civil Engineers.
Insect diversity at 19 stream sites dropped sharply at 8% to
15% imperviousness. Strong relationship between insect
diversity and habitat quality; majority of 53 urban streams
had poor habitat (Delaware). 1
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Brown, L.R.,
Gregory, M.B., and May, J.T. 2009. Relation of urbanization
to stream fish assemblages and species traits in nine
metropolitan areas of the United States. Urban Ecosystems
12(4): 391-416.
We examined associations of fish assemblages and fish
traits with urbanization and selected environmental variables
in nine major United States metropolitan areas. The strongest
relations between fishes and urbanization occurred in the
metropolitan areas of Atlanta, Georgia; Birmingham, Alabama;
Boston, Massachusetts; and Portland, Oregon. In these areas,
environmental variables with strong associations (rs ≥ 0.70)
with fish assemblages and fish traits tended to have strong
associations with urbanization. Relations of urbanization with
fish assemblages and fish traits were weaker in Denver,
Colorado; Dallas-Fort Worth, Texas; Milwaukee-Green Bay,
Wisconsin; and Raleigh, North Carolina. Environmental
variables associated with fishes varied among the metropolitan
areas. The metropolitan areas with poor relations may have had
a limited range of possible response because of previous
landscape disturbances. Given the complexities of urban
landscapes in different metropolitan areas, our results
indicate that caution is warranted when generalizing about
biological responses to urbanization.
D.W. 1997. Watershed urbanization impacts on stream quality
indicators in Northeastern Illinois.
pages 129-135
D. Murray and R. Kirshner (Eds.) Assessing the cumulative
impacts of watershed development on aquatic ecosystems and
water quality. Northeastern Illinois Planning Commission.
Chicago, IL.
Key finding:
There is a strong correlation between population density and
fish community assessments such that as population density
increased, community assessment scores went from the
better-good range to fair-poor (Illinois).
Abundance and recruitment of brown trout declines sharply at
10% to 15% imperviousness (Maryland). 1
Fraker, Michael E., Snodgrass, J.W., and Morgan, F. 2001.
Differences in Growth and Maturation of Blacknose Dace (Rhinichthys
atratulus) across an Urban-Rural Gradient. Copeia
Abstract: To investigate changes in the biology of
blacknose dace (Rhinichthys atratulus) populations
accompanying watershed urbanization, we sampled dace from four
watersheds in the Baltimore, Maryland area, representing a
gradient from urbanized to rural conditions. Dace from the
most urbanized watershed grew to greater standard lengths
during their first year of life when compared to dace from
other watersheds but grew little during their second year.
Dace from the other watersheds showed slower growth during
their first year but continued to grow through age II.
Approximately 90% of age I dace from the most urbanized
watershed were mature at age I, whereas only 25% of age I dace
from the other watersheds were mature. Dace from the most
urbanized watershed also reached maturity at shorter standard
lengths than dace from the other watersheds. Growth and
maturation of dace from the most rural watershed were similar
to those reported for dace from other regions. We conclude
that watershed urbanization results in increased growth rates
of young blacknose dace, and in heavily urbanized (. 90% urban
land use) watersheds, decreased age and size at maturity.
Available online.
Abstract: To investigate changes in the biology of
blacknose dace (Rhinichthys atratulus) populations
accompanying watershed urbanization, we sampled dace from four
watersheds in the Baltimore, Maryland area, representing a
gradient from urbanized to rural conditions. Dace from the
most urbanized watershed grew to greater standard lengths
during their first year of life when compared to dace from
other watersheds but grew little during their second year.
Dace from the other watersheds showed slower growth during
their first year but continued to grow through age II.
Approximately 90% of age I dace from the most urbanized
watershed were mature at age I, whereas only 25% of age I dace
from the other watersheds were mature. Dace from the most
urbanized watershed also reached maturity at shorter standard
lengths than dace from the other watersheds. Growth and
maturation of dace from the most rural watershed were similar
to those reported for dace from other regions. We conclude
that watershed urbanization results in increased growth rates
of young blacknose dace, and in heavily urbanized (. 90% urban
land use) watersheds, decreased age and size at maturity.
King, R.S.,
J.R. Beaman, D.F. Whigham, A.H. Hines, M.E. Baker, and D.E.
Weller. 2004. Watershed land use is strongly linked to
PCBs in white perch in
Bay subestuaries.
Environmental Science and Technology 38:6546-6552.
We related total PCBs (t-PCBs) in white perch (Morone
americana), an abundant estuarine resident that supports a
valuable recreational and commercial fishery in the
mid-Atlantic region, to the amount and spatial arrangement of
developed land in watersheds that discharge into 14
subestuaries of Chesapeake Bay. We considered the intensity of
development in watersheds using four developed land-use
measures (% impervious surface, % total developed land, %
high-intensity residential + commercial [%high-res/comm], and
% commercial) to represent potential source areas of PCBs to
the subestuaries. We further evaluated the importance of
source proximity by calculating three inverse-distance
weighted (IDW) metrics of development, an approach that
weighted developed land near the shoreline more heavily than
developed land farther away. Unweighted percentages of each of
the four measures of developed land explained 51−69% of the
variance in t-PCBs. However, IDWs markedly improved the
relationships between % developed land measures and t-PCBs.
Percent commercial land, weighted by its simple inverse
distance, explained 99% of the variance in t-PCBs, whereas the
other three measures explained as much as 93−97%. PCBs
historically produced or used in commercial and residential
areas are apparently persisting in the environment at the
scale of the watersheds and subestuaries examined in this
study, and developed land close to the subestuary has the
greatest unit effect on t-PCBs in fish. These findings provide
compelling evidence for a strikingly strong linkage between
watershed land use and t-PCBs in white perch, and this
relationship may prove useful for identifying unsampled
subestuaries with a high risk of PCB contamination.
K.E. and R. E. Schmidt. 1990. Patterns of fish spawning in
River tributaries: response to an urban gradient?
Ecology 71:1238-1245.
Resident and anadromous fish eggs and larvae declined
sharply in 16 tributary streams greater than 10%
imperviousness (New York). 1
Large rivers are not well understood with respect to
ecological patterns and processes. Although some
generalizations have been made, the geographic scope of large
rivers presents considerable sampling difficulties for
evaluation of many system-wide phenomena. Furthermore, studies
of large rivers often fail to consider interactions between
the lotic portion and surrounding watershed. Two features of
many large river watersheds, their large geographic extent and
their occupation and use by humans, should render them good
candidates for the manifestation of anthropogenic, ecological
gradients. One approach is to examine properties of tributary
watersheds within the overall drainage basin, as a function of
urbanization. We demonstrate the approach with a study
conducted to evaluate the contribution of nontidal tributaries
to anadromous fish spawning within a large, riverine estuary.
M.R., Coles, J.F., and Zappia, H. 2005. Fish assemblage
responses to urban intensity gradients in contrasting
metropolitan areas: Birmingham, Alabama, and Boston,
Massachusetts. In Brown, L.R., Gray, R.H., Hughes, R.M.,
and Meador, M.R., eds., Effects of urbanization on stream
ecosystems. American Fisheries Society, Symposium 47,
Bethesda, Maryland, p. 409-423.
We examined fish assemblage responses to urban intensity
gradients in two contrasting metropolitan areas: Birmingham,
Alabama (BIR) and Boston, Massachusetts (BOS). Urbanization
was quantified by using an urban intensity index (UII) that
included multiple stream buffers and basin land uses, human
population density, and road density variables. We evaluated
fish assemblage responses by using species richness metrics
and detrended correspondence analyses (DCA). Fish species
richness metrics included total fish species richness, and
percentages of endemic species richness, alien species, and
fluvial specialist species. Fish species richness decreased
significantly with increasing urbanization in BIR (r = –0.82,
P = 0.001) and BOS (r = –0.48, P = 0.008). Percentages of
endemic species richness decreased significantly with
increasing urbanization only in BIR (r = – 0.71, P = 0.001),
whereas percentages of fluvial specialist species decreased
significantly with increasing urbanization only in BOS (r =
–0.56, P = 0.002). Our DCA results for BIR indicate that
highly urbanized fish assemblages are composed primarily of
largescale stoneroller Campostoma oligolepis, largemouth bass
Micropterus salmoides, and creek chub Semotilus atromaculatus,
whereas the highly urbanized fish assemblages in BOS are
dominated by yellow perch Perca flavescens, bluegill Lepomis
macrochirus, yellow bullhead Ameiurus natalis, largemouth
bass, pumpkinseed L. gibbosus, brown bullhead A. nebulosus,
and redfin pickerel Esox americanus. Differences in fish
assemblage responses to urbanization between the two areas
appear to be related to differences in nutrient enrichment,
habitat alterations, and invasive species. Because species
richness can increase or decrease with increasing
urbanization, a general response model is not applicable.
Instead, response models based on species' life histories,
behavior, and autecologies offer greater potential for
understanding fish assemblage responses to urbanization.
J., M. McGinty, B. Richardson, P. Piavis, H. Speir, and M.F.
Topolski. 2005. Interim assessment of yellow perch Perca
flavescens habitat and population dynamics in
River, a suburbanized Chesapeake Bay sub-estuary.
Fisheries Technical Report Series, Number 46, Maryland
Department of Natural Resources, Fisheries Service,
The Severn River, located on the Chesapeake Bay's western
shore within the rapidly developing Baltimore-Washington D.C.
corridor, has been closed to yellow perch harvest since 1989
in response to largely unknown, but assumed detrimental
habitat conditions. During 2001-2003, we assessed yellow perch
habitat in the heavily developed Severn River watershed (17%
impervious surface or IS) by combining stock assessment
(larvae-adults), experimental stocking (larvae-juveniles), and
water quality monitoring (temperature, salinity, dissolved
oxygen). We contrasted yellow perch population and water
quality characteristics in Severn River with developed
reference systems (10-20% IS), relatively undeveloped
reference systems (≈ 2% IS), and historic Severn River data
from periods of lesser development. Hatching success of Severn
River eggs was extremely low and larval relative abundance was
very low during 2001-2003. Wild juveniles were not caught in
summer during 2001, were present at very low levels in 2002,
and were better represented during 2003. Hatchery juveniles
were common after stocking during 2002-2003. Adult yellow
perch did not exhibit excessive non-harvest related mortality
or decreased growth. At this time, depressed egg and larval
viability appear to be critical factors suppressing the
resident population. Two significant habitat quality issues
potentially impacting yellow perch population dynamics were
described in our study of Severn River – possible salinity
intrusion into the upper tidal spawning area and larval
nurseries due to landscape changes, and poor summer dissolved
oxygen (DO) throughout juvenile and adult habitat. Frequent
violations of salinity requirements were observed for larvae
(93% of measurements) and dissolved oxygen violations were
common for juveniles and adults in summer (≈5% at the surface,
20-40% at mid-depth, 70-80% at the bottom). Based on our
study, dissolved oxygen conditions unsuitable for yellow perch
survival were common in urbanized watersheds and uncommon in
less urbanized systems. Other issues, such as contaminants,
exist that were not covered in the habitat variables we
evaluated. If poor egg and larval viability observed in the
Severn River is now normal, then the river's population may be
entirely dependent upon immigration of good Head-of-Bay
Uphoff, J.
H. 2008. Identifying priority areas for protection and
Bay striped bass spawning and larval nursery areas as a model.
Fisheries Technical Report Series Number 52, Maryland
Department of Natural Resources, Fisheries Service,
Weaver, L.A.
1991. Low-intensity watershed alteration effects on fish
assemblage structure and function in a
Virginia piedmont stream. Unpublished Masters Thesis.
Commonwealth University. 77 pp.
Key finding: As watershed
development increased to about 10%, fish communities
simplified to more habitat and trophic generalists and fish
abundance and species richness declined.
IBI scores for the urbanized stream fell from the good to fair category (Virginia).
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Coles, J.F.,
Bell, A.H., Scudder, B.C., and Carpenter, K.D. 2009. The
effects of urbanization and other environmental gradients on
algal assemblages in nine metropolitan areas across the United
States. U.S. Geological Survey Scientific Investigations
Report 2009-5022, 18 p.
The U.S. Geological Survey conducted studies from 2000 to 2004
to determine the effects of urbanization on stream ecosystems
in nine major metropolitan study areas across the United
States. Biological, chemical, and physical components of
streams were assessed at 28 to 30 sites in each study area.
Benthic algae were sampled to compare the degree to which
algal assemblages correlated to urbanization, as characterized
by an urban intensity index (UII), relative to other
environmental gradients that function at either the watershed
or reach scales. Ordination site scores were derived from
principal components analyses of the environmental data to
define environmental gradients at two spatial scales: (1)
watershed-scale gradients that summarized (a) landscape
modifications and (b) socioeconomic factors, and (2)
reach-scale gradients that characterized (a) physical habitat
and (b) water chemistry. Algal response was initially
quantified by site scores derived from nonmetric
multi-dimensional scaling ordinations of the algal assemblage
data. The site scores were then correlated with a set of algal
metrics of structure and function to help select specific
indicators that would best represent changes in the algal
assemblages and would infer ecological condition. The selected
metrics were correlated to the UII and other environmental
gradients. The results indicated that diatom-taxa in the
assemblages were distinctly different across the nine study
areas, likely due to physiographic differences across the
country, but nevertheless, some algal metrics were applicable
to all areas. Overall, the study results indicated that
although the UII represented various landscape changes
associated with urbanization across the country, the algal
response was more strongly related to more specific factors
generally associated with water quality measured within the
stream reach.
M., Coles, J. F., Giddings, E.M., and Zappia, H. 2005. A
comparison of the influences of urbanization on stream benthic
algal assemblages in contrasting environmental settings.
In Brown, L.R., Gray, R.H., Hughes, R.M., and Meador, M.R.,
eds., Effects of urbanization on stream ecosystems. American
Fisheries Society, Symposium 47, Bethesda, Maryland,
Patterns of stream benthic algal assemblages along
urbanization gradients were investigated in three metropolitan
areas—Boston (BOS), Massachusetts; Birmingham (BIR), Alabama;
and Salt Lake City (SLC), Utah. An index of urban intensity
derived from socioeconomic, infrastructure, and land-use
characteristics was used as a measure of urbanization. Of the
various attributes of the algal assemblages, species
composition changed along gradients of urban intensity in a
more consistent manner than biomass or diversity. In urban
streams, the relative abundance of pollution tolerant species
was often higher than in less affected streams. Shifts in
assemblage composition were associated primarily with
increased levels of conductivity, nutrients, and alterations
in physical habitat. Water mineralization and nutrients were
the most important determinants of assemblage composition in
the BOS and SLC study areas; flow regime and grazers were key
factors in the BIR study area. Species composition of algal
assemblages differed significantly among geographic regions,
and no particular algal taxa were found to be universal
indicators of urbanization. Patterns in algal biomass and
diversity along urban gradients varied among study areas,
depending on local environmental conditions and habitat
alteration. Biomass and diversity increased with urbanization
in the BOS area, apparently because of increased nutrients,
light, and flow stability in urban streams, which often are
regulated by dams. Biomass and diversity decreased with
urbanization in the BIR study area because of intensive fish
grazing and less stable flow regime. In the SLC study area,
correlations between algal biomass, diversity, and urban
intensity were positive but weak. Thus, algal responses to
urbanization differed considerably among the three study
areas. We concluded that the wide range of responses of
benthic algae to urbanization implied that tools for stream
bioassessment must be region specific.
Palmer, M.
A. 2009. Reforming watershed restoration: science in need
of application and applications in need of science.
Estuaries and Coasts 32:1-17.
Coastal and inland waters are continuing to decline in many
parts of the world despite major efforts made to restore them.
This is due in part to the inadequate role that ecological
science has played in shaping restoration efforts. A
significant amount of fundamental ecological knowledge dealing
with issues such as system dynamics, state changes,
context-dependency of ecological response, and diversity is
both under-used by managers and practitioners and
under-developed by ecologists for use in real-world
applications. Some of the science that is being 'used' has not
been adequately tested. Thus, restoration ecology as a science
and ecological restoration as a practice are in need of
reform. I identify five ways in which our ecological knowledge
should be influencing restoration to a far greater extent than
at present including a need to: shift the focus to restoration
of process and identification of the limiting factors instead
of structures and single species, add ecological insurance to
all projects, identify a probabilistic range of possible
outcomes instead of a reference condition, expand the spatial
scale of efforts, and apply hierarchical approaches to
prioritization. Prominent examples of restoration methods or
approaches that are commonly used despite little evidence to
support their efficacy are highlighted such as the use of only
structural enhancements to restore biodiversity. There are
also major gaps in scientific knowledge that are of immediate
need to policy makers, managers, and restoration practitioners
including: predictive frameworks to guide the restoration of
ecological processes, identification of social-ecological
feedbacks that constrain ecosystem recovery and data to
support decisions of where and how to implement restoration
projects to achieve the largest gains. I encourage ecologists
to respond to the demand for their scientific input so that
restoration can shift from an engineering-driven process to a
more sustainable enterprise that fully integrates ecological
processes and social science methods.
Available online
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Booth, D.B.
2000. Forest cover, impervious surface area, and the
mitigation of urbanization impacts in King County, Washington.
King County Water and Land Resources Division. Seattle, WA.
Booth provides a review of the scientific framework for basing
management decisions on the impact of urbanization on aquatic
systems and the use of impervious cover as an indicator. The
ability of forest cover to minimize impacts on stream
stability at low levels of impervious cover is documented.
Also expressed, is the concept that impervious cover, as a
single land use parameter, may not be an appropriate indicator
of stream health in rural watersheds with impervious cover
measurements of less than 10%. 2
Resources Management (ERM). 2000. Stream condition
cumulative impact models for the
Prepared for the Maryland-National Park and Planning
Commission, Silver Spring, MD.
Key finding:
A study of first and second order stream conditions in
urbanized watersheds found that for streams rated as being in
excellent or good condition watersheds had either high levels
of riparian buffers (>67%) or moderate buffers (>33%) in
combination with moderate storm water management (at least 33%
of imperviousness treated) (Maryland).
Horner, R.,
May, C., Livingston, E., and J. Maxted. 1999. Impervious
cover, aquatic community health, and stormwater BMPs: Is there
a relationship?
This study, using watersheds in Maryland, Texas, Colorado and
Washington state, evaluated the ability of structural and
nonstructural management practices to mitigate and ameliorate
the impacts of impervious surfaces on biological communities.
It found that nonstructural techniques such as riparian
buffers and upland forest retention were more effective at
ameliorating the impacts of impervious surfaces than
structural management practices. They did, however, conclude
that the ability of these nonstructural techniques to mitigate
biological impacts was limited to low levels of impervious
cover and that at higher levels of impervious cover biological
impacts were difficult to prevent. 2
Available online.
Jones, R.C.,
Via-Norton, A., and D. Morgan. 1996. Bioassessment of the
BMP effectiveness in mitigating stormwater impacts on aquatic
biota. In: Effects of Watershed Development and Management
on Aquatic Ecosystems. Roesner,
L.A. (ed.), Proceedings of ASCE/Engineering Foundation
Conference. August, 1996. Snowbird, UT.
Key finding:
Unable to show improvements in biological community at
8 sites downstream of stormwater treatment practices as
compared to reference conditions (Virginia).
Maxted, J.
and E. Shaver. 1996. The Use of Retention Basins to
Mitigate Stormwater Impacts on Aquatic Life. L. In:
Effects of Watershed Development and Management on Aquatic
Ecosystems. Roesner, L.A. (ed.), Proceedings of Engineering
Foundation Conference. August, 1996. Snowbird, UT.
Key finding:
No significant difference in biological and physical metrics
for 8 stormwater treatment practice (STP) sites versus 33
sites without STPs (with varying impervious area). STP s did
not attenuate the impacts of urbanization once the watershed
reached 20% impervious cover, and did not prevent a shift in
the macroinvertebrate community from pollutant sensitive
species to pollutant tolerant organisms (Delaware).
Research Council. 2009. Urban stormwater management in the
National Academies Press, Washington, D.C.
The rapid conversion of land to urban and suburban areas has
profoundly altered how water flows during and following storm
events, putting higher volumes of water and more pollutants
into the nation's rivers, lakes, and estuaries. These changes
have degraded water quality and habitat in virtually every
urban stream system. The Clean Water Act regulatory framework
for addressing sewage and industrial wastes is not well suited
to the more difficult problem of stormwater discharges. This
book calls for an entirely new permitting structure that would
put authority and accountability for stormwater discharges at
the municipal level. A number of additional actions, such as
conserving natural areas, reducing hard surface cover (e.g.,
roads and parking lots), and retrofitting urban areas with
features that hold and treat stormwater, are recommended.
Available to read online.
(return to top of page)
finding summarized in: Schueler, T.R. and H.K. Holland. 1994.
The importance of imperviousness. Watershed Protection
Techniques 1(3): 100-111.
Key finding summarized in: Cappiella, K., and K. Brown.
2001. Impervious cover and land use in the Chesapeake Bay
watershed. Center for Watershed Protection, Ellicott City,
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