The world’s population is concentrated in urban areas. This change in demography has brought landscape transformations that have a number of documented effects on stream ecosystems. The most consistent and pervasive effect is an increase in impervious surface cover within urban catchments, which alters the hydrology and geomorphology of streams. This results in predictable changes in stream habitat. In addition to imperviousness, runoff from urbanized surfaces as well as municipal and industrial discharges result in increased loading of nutrients, metals, pesticides, and other contaminants to streams. These changes result in consistent declines in the richness of algal, invertebrate, and fish communities in urban streams. Although understudied in urban streams, ecosystem processes are also affected by urbanization. Urban streams represent opportunities for ecologists interested in studying disturbance and contributing to more effective landscape management.

/pdf/streams-in-the-urban-landscape-mt89v53ix5.pdf

Streams in the Urban Landscape

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.

/pdf/impervious-surface-coverage-the-emergence-of-a-key-344g6x5phu.pdf

Impervious surface coverage: the emergence of a key environmental indicator

Impervious surfaces have for many years been recognized as an indicator of the intensity of the urban environment and, with the advent of urban sprawl, they have become a key issue in habitat health. Although a considerable amount of research has been done to define impervious thresholds for water quality degradation, there are a number of flaws in the assumptions and methodologies used. Given refinement of the methodology, accurate and usable parameters for preventative watershed planning can be developed, which include impervious surface thresholds and a balance between pervious and impervious surfaces within a watershed.

/pdf/impervious-surfaces-and-water-quality-a-review-of-current-44t2v7vgj3.pdf

Impervious Surfaces and Water Quality: A Review of Current Literature and Its Implications for Watershed Planning

Since the 1940s it has been proposed that landscape dissection into distinct valleys is limited by a threshold of channelization that sets a finite scale to the landscape This threshold is equal to the hillslope length that is just shorter than that necessary to support a channel head A field study supports this hypothesis by showing that an empirically defined topographic threshold associated with channel head locations also defines the border between essentially smooth, undissected hillslopes and the valley bottoms to which they drain This finding contradicts assertions that landscapes are scale-independent and suggests that landscape response to changes in climate or land use depends on the corresponding changes in the threshold of channelization

Channel initiation and the problem of landscape scale.

Identification and quantification of the hydrological impacts of imperviousness in urban catchments: A review

Morphometric parameters such as drainage density, stream magnitude, and relief ratio are practical measures of flood potential in small (<100 mi2) drainage basins. Stereoscopic interpretation of low-altitude aerial photographs provides the most accurate maps of basins for generating these parameters. Field surveys of a high-density limestone basin in central Texas show that 1:24,000 scale topographic maps accurately portray the efficient stream channel system but fail to reveal numerous small gullies that may form portions of hillslope hydrologic systems. Flood potential in drainage basins can be defined by a regional index computed as the standard deviations of the logarithms of the annual maximum streamflows. High potential basins tend toward greater relief, greater drainage density, and thus greater ruggedness numbers than low–flash flood potential watersheds. For a given number of first-order channels (basin magnitude), flash flood regions have greater ruggedness numbers, indicating higher drainage densities combined with steep hillslopes and stream channel gradients. Transient controls on flood response, such as differences between local rainstorm intensities, appear to be the major influences on hydrographs in areas of moderate dissection and relief. Morphometric parameters for low-potential flash flood regions )Indiana and the Appalachian Plateau( are better estimators of frequent low-magnitude runoff events (mean annual flood), while the same parameters correlate better with the maximum flood of record in high-flood potential regions (central Texas, southern California, and north central Utah).

Morphometry and floods in small drainage basins subject to diverse hydrogeomorphic controls

The watershed of Sawmill Brook is undergoing urbanization that has increased the frequency of bankfull discharge. The increased runoff is causing extensive bank erosion in the main channel that has increased the size of the bed material and the rate of bedload discharge. The increased frequency of moderate floods, the channel widening, and the change in the sediment transport regime is causing a change from a meandering to a braided channel pattern. With continued urbanization of the basin the present disequilibrium of the channel will be enhanced resulting in an unstable channel pattern for Sawmill Brook.

Sawmill Brook: An Example of Rapid Geomorphic Change Related to Urbanization

Ephemeral-stream processes: Implications for studies of quaternary valley fills

Current statistical methods may be unable to accurately predict recurrence intervals of rare, large-magnitude floods, especially in semiarid regions having positively skewed annual flood distributions, great hydrologic variability, and widely spaced gaging stations. Current approaches rely on historical data, but catastrophic floods may have recurrence intervals far greater than the length of historical records. In the lower Pecos and Devils Rivers of southwestern Texas, paleoflood discharge and frequency estimates are extended over 10,000 years by the study of slack-water flood sediments. Slack-water deposits are typically fine-grained sand and silt that accumulate during floods in areas where current velocity is reduced, i.e., in back-flooded tributary mouths, channel expansions, downstream from bedrock spurs and/or slump blocks, and in shallow caves along bedrock walls. Radiocarbon dating of organic detritus in slack-water deposits establishes the flood chronology while paleoflood discharges can be estimated by slope-area techniques. Paleoflood information extracted from slack-water sediments can greatly extend flood records. These floods may be weighted like historical data in log Pearson type 3 calculations of flood frequency. Our morphostratigraphic approach combines recorded data with geomorphic evidence to derive estimates of flood frequency. This technique offers an inexpensive and rapid way to assess catastrophic flood risk.

Paleohydrology of southwestern Texas

The Cheney-Palouse tract of the channeled scabland is the largest continuous tract of scabland in eastern Washington. The tract is composed of a varied assortment of bedrock erosional forms, loess islands, and gravel bars. Prominent bedrock longitudinal grooves and inner channels formed by macroturbulent plucking erosion of the jointed rock. Loess island forms vary as a function of their position within the flow. The three major types (submerged, partially submerged, and subaerially exposed) created sedimentologic conditions and resulting bar forms distinct from one another. Other bar forms, notably expansion bars, account for most of the sedimentation in the tract.

/pdf/origin-of-the-cheney-palouse-scabland-tract-14it1npqbi.pdf

Origin of the Cheney-Palouse Scabland tract

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Peter C. Patton

Author Tools

Chat about Author