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About the Author
Ann L. Riley is executive director of the Waterways Restoration Institute, where she works on the design and installation of stream restoration projects. She is involved in the evaluation of national water policy for the National Research Council, the Institute for Water Resources, and federal task forces.
A Video Tour of Ecological Restoration Techniques Led by Anne Riley (Video documentary - 61 min) is available from www.urbanstreamrestoration.com.
Read an Excerpt
Restoring Streams in Cities
A Guide for Planners, Policy makers, and Citizens
By Ann L. Riley, Luna B. Leopold, Stefen, Dennis O'Connor
ISLAND PRESSCopyright © 1998 Ann L. Riley
All rights reserved.
Basics on Streams
Streams are a resource generally taken for granted or completely ignored, but we all live in a watershed. To begin learning about your local streams, become familiar with the watershed they run through and the history that comes with them.
What Is a Creek?
It has been very much a surprise to me that the most common question phoned into my office has been "What is the difference between a creek and a stream?"—or "How do I tell the difference between a stream, a brook, and a river?" No one has quantified the differences between brooks, creeks, gulches, washes, and rivers, and these mostly loosely defined terms represent cultural and regional customs more than they define or "standardize" a geographic feature.
Look at a U.S. Geological Survey map of your area and pick out the names of the drainages. If you are living in the northeastern part of the United States, you can see a number of "brooks" on your topographic map. In the Adirondacks, I hiked along Johns Brook, Wolf Jaws Brook, Calamity Brook, Black Brook, and Deer Brook. In the Boston vicinity (eastern Massachusetts and New Hampshire), you may live near Lubbur Brook, Meadow Brook, Bachelder Brook, Bull Brook, Muddy Run, or Frost Fish Brook. In Virginia in the suburbs of Washington, D.C., you may walk along South Run, or you may live along Stony Run, Roland Run, or Whitemash Run in the suburbs of Baltimore. In Washington, D.C., along the Potomac River, you can walk along Rock Creek or the Chesapeake and Ohio Canal. A map of the Carolinas shows widespread use of the word "creek." You may live along Buffalo Creek in Greensboro, Bolin Creek in Chapel Hill, Jefferson Creek or Crabtree Creek in Raleigh. Creek also appears to be the preferred nomenclature for waterways in Iowa and Wisconsin. In Duluth, you may live along Dutchman or Bluff creek. North and South Dakotas' maps also show a preponderous use of creeks for the waterways.
A Wyoming map shows common usage of creek but also shows the use of the term "fork," as in Hams Fork, Blacks Fork, and Henry's Fork, tributaries to the Green River. Different branches of the same creek are also sometimes called fork, such as the North and South forks of Owl Creek near Thermopolis. Draws and gulches appear on topographic maps near Pinedale, Wyoming, with names like Millie Draw, Clarke Draw, Nutting Draw, and Horse Draw and Coyote Gulch, tributaries to the Hoback River. North Hay Gulch, Big Draw, and Brodie Draw are tributaries to the Green River. Deadman Wash, Table Wash, Alkali Wash, and Pine Creek Wash flow near Rock Springs, Wyoming. In New Mexico near Roswell, Rio Penasco, Rio Bonito, and Rio Hondo flow into the Pecos River. Arroyos and washes abound in Arizona and New Mexico, including the well-known Indian Bend Wash flowing through the middle of Scottsdale, Arizona. Dreamy Draw Wash flows through Paradise Valley.
What someone in Wyoming calls a draw, or in New Hampshire a creek, someone in Florida, Alabama, or Louisiana may call a rigolet or bayou. Bayous are also known as backwaters off main channels of rivers or streams. Alaska maps show similar backwaters as arms. "Slough" is another synonym for creek, such as Dead Horse Slough, a tributary to Big Chico Creek in Chico, California, and Mercer Slough, which is located in Bellevue, Washington, as a creek and backwater of Lake Washington.
Creek is a generic term for a small stream and originated in New England, where it retains its original meaning as a tidal inlet. In the rest of the country, creek has evolved to mean a flowing stream smaller than a river. When a creek or a stream becomes a river is anyone's call. We can probably find some relative correlation between greater flows and drainages named rivers, but there are also creeks on topographic maps that contain greater flows than so-called rivers.
Brook, another word for creek or stream, also has its origins in English culture and dominates New England. Arroyo is Spanish for "brook," but in the southwest landscape, where we find the use of this word, we see it being used to describe not constantly flowing perennial drainages, but channels that are often dry and have occasional, seasonal, or intermittent flows. Gulch, gully, ravine, and draw, terms used commonly in the western United States, seem to be relatively interchangeable. Rigolet, derived from the French rigole, or "ditch," is used occasionally in areas of American-French influence. Fork generally designates a branch or tributary of a stream.
What this definition problem tells us really is that creeks, brooks, streams, rivers, and the rest are important components of our landscape history. There can be much colorful folklore associated with drainages—large and small—and the researcher of a local history can start with the names of drainages to learn about an area. An example of a folk name associated with creeks is Troublesome Creek, a name given by the general population in an area because of historical local events. Descriptive names such as Stinking Spring, Roaring Run, Rushing Water Creek; incident names such as Murder Creek, Earthquake Creek, Stray Horse Gulch; and exclamation names such as Helpmejack Creek and Goshhelpme Creek all have stories behind the names. Of course, some local drainages are named for the native people who once lived along them or for the early settlers who displaced the native people.
The question of what a creek or stream is in a geographical or geologic sense must be answered in the context of what a watershed is.
Watersheds and the Hydrologic Cycle
Everyone lives in a watershed. The hydrologic cycle of water falling to the earth in the form of rain, snow, sleet, and hail, then running off the land into creeks, rivers, ponds, lakes, marshes, storm sewers, and human- made channels and ultimately into oceans happens everywhere. Some of the water that falls is caught by tree leaves, some soaks into the ground, some runs off pavement, rooftops, and lawns, and some is collected into small rills on the hillsides that collect more water into gullies and channels as creeks, rivers, and desert arroyos. Some of the water from streams, rivers, ponds, lakes, reservoirs, and oceans evaporates and then falls to the earth again in some form of precipitation.
A watershed is the land area drained by a particular stream or river. We can think of a watershed or water basin on the scale of the Mississippi River, which drains with the help of many tributary rivers and streams about 1,250,000 square miles—or we can work on the scale of a creek that drains a watershed area of 1 square mile that contributes stream flow to a larger downstream drainage. A good way to classify your stream to avoid the inherent ambiguity of the words creek, stream, river, and gulch is to designate its order. Small streams join to form larger streams in a branching pattern that forms a drainage network. Therefore, larger watersheds are made up of a joining of smaller watersheds. Figure 1.1 illustrates this watershed within a watershed by showing the Fremont Creek watershed as a part of the Clear River watershed. The different channels draining these watersheds can be designated by how many tributaries they have, or by order. A first-order stream channel has no tributaries; when two first-order streams join, they create a second-order stream. When two second-order streams join, they create a third-order stream, and so on. If you designate your stream by its order, therefore, others can immediately get a concept of the size of the drainage area you are concerned with.
The total length of rivers in the United States, including all the minor creeks and draws, has been estimated to be about 3 million miles. There are also estimates of the average lengths of the different order streams and their mean drainage areas based on a national average and mean. The average length for a first-order stream is 1 mile, with a mean drainage area of 1 square mile. The average length of a second-order stream is 2.3 miles, with a mean drainage area of 4.7 square miles, and the average length of a third-order stream is about 5.3 miles in a drainage area of about 23 square miles. The average fourth-order stream is an average of 12 miles long in a mean watershed size of 109 square miles. The largest rivers of the world are ten-order drainages. A river the size of the Allegheny River in the eastern United States represents a seventh-order river, the average length of which is 147 miles and the mean drainage area 11,700 square miles.
In Figure 1.1, Fremont Creek is a third-order stream, and upper Fremont Creek above the hypothetical town of Fremont is a second-order stream. For the purposes of planning, you can draw in the watershed above any point in the drainage system. In the same figure, we have drawn the watershed boundaries that affect the town of Fremont for addressing future floodplain-planning problems that will be discussed in chapter 7.
Stream drainages follow the lowest topography and form valleys and become separated from each other by ridges or divides. Streams on one side of a ridge drain the water into one stream system, while the streams on the other side drain a separate valley. Topographic maps use contour lines to designate divides, valleys, and drainage patterns and to connect points of the same elevation. If the lines are evenly spaced and far apart, they represent a gently sloping landscape. Closely spaced and jagged lines indicate a steep and rough landscape. A topographic map gives you a three-dimensional picture of your watershed; the boundaries of the watershed are indicated by the hills and ridges for your drainage. You can measure the drainage area and understand how your stream and its watershed relate to other watersheds. Find out what stream, river, or other body of water your stream flows into. This other body of water may have a great deal of influence on the behavior of your stream.
The water cycle is the other basic concept that helps define the function of your stream. The basic source of most atmospheric water is the ocean, which evaporates and provides the moisture for the precipitation that returns to the earth. The continental United States receives an average of 30 inches of precipitation a year, and evapotranspiration and transpiration from plants return approximately 21 inches to the atmosphere. The balance of 9 inches contributes to the flow of streams and rivers. In the words of Luna Leopold, a well-known river scientist:
Rivers are both the means and the routes by which the products of continental weathering are carried to the oceans of the world. Except in the most arid areas more water falls as precipitation than is lost by evaporation and transpiration from the land surface to the atmosphere. Thus there is an excess of flow which must flow to the ocean. Rivers then are the routes by which this excess water flows to the ultimate base level. The excess of precipitation over evaporation and transpiration provides the flow of rivers and springs, recharges groundwater storage, and is the supply from which man draws water for his needs.
No matter how big or small your stream is, or what you call it, the same principles govern its behavior. The concepts explained in this book about river dynamics apply to stream orders one through ten. Most of the solutions—or at least the principles behind the solutions—apply to all creeks, streams, rigolets, arroyos, and rivers (although the experience of the author is limited to sixth-order rivers and below). Sometimes this book refers to creeks and sometimes to streams and rivers. Don't be put off by the interchangeable use of these terms. Whether you live by the Missouri River or Old Man's Creek, the content in this book will be helpful to you.
The Value of Streams and Restoration
Streams and rivers are industrial transportation corridors, industrial water supplies, and domestic and agricultural supplies. Their waters produce fish for sportfishing and provide for a recreational industry of white- water rafting, kayaking, and canoeing. They inspire trails, greenbelts, and parks and can enhance the values of commercial areas and downtowns of cities by attracting people to them. They can even be tourist attractions. Riparian (streamside) vegetation along streams has important value for aesthetics, shade, and wildlife habitat.
The industrial, agricultural, and land development values that produce large cash returns from rivers and streams tend to be the values that dominate the uses and management of streams and rivers. There is a modest body of literature developing that assigns monetary values to recreational, aesthetic, wildlife and riparian, and community uses of streams. You may need to rely on some of this literature to help convince political bodies of the importance of the environmental values of streams and rivers and their fisheries.
Resource economists are engaged in describing and quantifying the value of streams using five types of strategies: One is a traditional economic evaluation of natural resources values used by recreation- oriented studies to identify user expenditures associated with a river site. Costs of gear and travel to recreate at the stream are quantified to provide a tangible dollar figure showing how much river users are willing to spend to enjoy the resource. A second method quantifies the changes in real estate and business location values that can be associated with the ability of a waterway to create a higher quality of life for the area in which it is located. A related method quantifies how a stream or river project, such as a flood-control or hydroelectric project, may redistribute the benefits of a river or the costs associated with modifying the river. A fourth innovation in economic analysis quantifies the inherent values that the public places on just knowing the resource is there, for ecological values, regional identity, or other broad concepts. A fifth area of economic evaluation that is in the pioneer stages of being developed is evaluation of the relative benefits of environmental restoration projects that form a part of or substitute for conventional public works, storm-water management, erosion and flood-control projects.
A publication available from the National Park Service, Economic Impacts of Protecting Rivers, Trails and Greenway Corridors, is an easy-to-understand resource book for computing the economic value of open space, trails, river corridors, and other features of the natural environment to a community's property values and tax base. The report presents quantifiable evidence that these "greenways" increase nearby property values, help support recreation-oriented businesses, attract tourists, attract government expenditures, attract corporation relocations, and reduce local costs for services such as roads, sewers, and flood control. A study in Boulder, Colorado, for example, shows that the aggregate property value for one neighborhood was approximately $5.4 million greater with a greenbelt than without it. The presence of the greenbelt produced about $500,000 additional property tax revenue. The purchase price of the greenbelt was $1.5 million, and the property tax increase alone could recover that cost in just three years.
Another National Park Service study, from 1982, uses economic measures to quantify how the public places value on the intrinsic benefits of fish and wildlife and riparian resources. The methods used to quantify these values include direct inquiry as to the public's willingness to pay for the enhancement of fish and wildlife values and an indirect observation of recreators' activities and expenditures related to the resources. For example, a survey in the city of Sacramento showed that residents assigned a fair value to compensate a landowner for the loss of 1 acre of healthy riparian habitat along the Sacramento River at about $24,000.
A report written for the Department of the Interior by the University of Kentucky specifically addressed the issue of evaluating the aesthetic and recreational potential of small streams located in or near cities. The study focused on two streams near Lexington, Kentucky, which were evaluated for their values for camping, picnicking, trails, aesthetic enjoyment, and scenic and historical resources. Case studies were used to estimate numbers of visits to sites, future demand for greenway use by an urban population plus the proportion of that demand that would be served by each creek site, and the economic benefits that would accrue if the sites were developed as educational preserves or recreational areas. This report was done in the context of a rapidly urbanizing county. While only 40 percent of the population lived in urban areas in 1900, in 1960 the number had grown to 68 percent. It is estimated that nearly 85 percent of the population will be concentrated in urban areas by the year 2000. What this suggests is that the economic values of natural environments in urban areas are going to continually increase because of the increased demand for them.
Excerpted from Restoring Streams in Cities by Ann L. Riley, Luna B. Leopold, Stefen, Dennis O'Connor. Copyright © 1998 Ann L. Riley. Excerpted by permission of ISLAND PRESS.
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Table of Contents
Table of Figures
Chapter 1. The Basics
Chapter 2. The Urban River Planners
Chapter 3. The Environmental Professionals
Chapter 4. River Scientists
Chapter 5. Hydraulic Engineers
Chapter 6. Restoration Is Ancient History
Chapter 7. Managing Floodplains
Chapter 8. Citizen-Supported Restoration Activities
Chapter 9. A Survey of Urban Watershed and Stream Restoration Methods
Glossary of Terms