Posted by: chrismaser | October 27, 2009

RIPARIAN AREAS AND FLOODPLAINS

Riparian areas and floodplains are coming under increasing pressures from urban development because of the misguided notion that we humans can unilaterally entrain streams and rivers with impunity, despite much growing evidence to the contrary. When a levee fails, the response seems always to be more levees and, if need be, more dams. We have yet to understand that a problem caused on one level of human consciousness cannot be fixed on the same level of consciousness.

If we are willing to risk moving to a higher level of consciousness, we can either prevent or repair much of the damage our shortsighted human activities cause. Take, for example, the Snake River near Jackson, Wyoming, where, in 1998, engineers, people from the Jackson Hole Conservation Alliance, the Wyoming Department of Fish and Game, and local officials began to restore part of the Snake River to a more natural condition.

For nearly 40 years, levees that line about 23 miles of the Snake River near Jackson had entrained high water from the melting snows of spring in the Teton Mountains and allowed lavish homes to invade the cottonwood forest of the river’s floodplain. Although researchers had known for some time the ecological havoc wreaked by dams, they finally began to recognize the ecologically destructive nature of levees and their “free-form cousin” riprap, which are piles of rock and earth dumped by landowners along streams and rivers to guard against erosion.

It is not surprising, therefore, that the 15-foot-high serpentine piles of rock created by the U.S. Army Corps of Engineers to protect farmers’ fields and hay meadows from flooding and erosion had caused serious and unexpected problems along one of the world’s most scenic stretches of river. The river had for centuries been true to its rhythm of flooding and receding in a fluid motion that constantly redesigned its five or six channels or “braids” as it dissipated the energy of its floodwaters each spring.

But, squeezed into one or two rigid channels, the upper Snake River had lost its ability to flood during the spring runoff. This lost ability had increased the velocity of the water from spring runoffs within the levee straitjacket, which in turn had caused the destruction by raging spring torrents of many of the large islands in the remaining channels, islands once occupied by willows and cottonwood trees. Moreover, the luxuriant forests of cottonwood that use to lined the river’s banks are fading into a past era for lack of young trees to replace the dying of the old because cottonwoods need periodic flooding to reproduce successfully. And Snake River cutthroat trout, which need clean gravel in which to spawn, had suffered from the channelization because floodwaters no longer flush and rejuvenate their spawning gravels.

In the autumn, of 1998, the Teton County Natural Resource District and the U.S. Army Corps of Engineers began testing methods of breathing life back into the river by restoring its rhythms of flooding. This undertaking, like all others, would require a different level of consciousness in order to succeed, as Rik Gay, manager of project for Teton County, pointed out when he said, “Rivers don’t just go downstream. We need to think in three dimensions. Rivers also move laterally and below the ground.”

There is a sober reminder in all of this, however. The levees along the upper Snake River not only had narrowed and denuded the river over the four decades but also had allowed million-dollar housing developments to flourish, which caused Bill MacDonald, manager of the Snake River project for the U.S. Army Corps of Engineers, to observe that restoring the natural flow of the river was “not feasible” because “behind those levees are millions, if not billions, of dollars in real estate.”1 What might an alternative for the future be?

When I was a boy, the Willamette River in western Oregon flooded every year, but it was something people expected and allowed for. If I remember correctly, that began to change in the late 1950s or early 1960s when the U.S. Army Corps of Engineers commenced building dams to control the flooding and “reclaim” the floodplains for human occupation. With this proclaimed reclamation came the human invasion of riparian areas and flood plains.

RIPARIAN AREAS

Riparian areas can be identified by the presence of vegetation that requires free or unbound water and conditions more moist than normal. These areas may vary considerably in size and the complexity of their vegetative cover because of the many combinations that can be created between the source of water and the physical characteristics of the site. Such characteristics include gradient, aspect of slope, topography, soil, type of stream bottom, quantity and quality of the water, elevation, and the kind of plant community.

Riparian areas have the following things in common:  (1) they create well-defined habitats within much drier surrounding areas, (2) they make up a minor portion of the overall area, (3) they are generally more productive than the remainder of the area in terms of the biomass of plants and animals, (4) wildlife use riparian areas disproportionately more than any other type of habitat, and (5) they are a critical source of diversity within an ecosystem.

There are many reasons why riparian areas are so important to wildlife, but not all can be attributed to every area. Each combination of the source of water and the attributes of the site must be considered separately. Some of these reasons are as follows:

1. The presence of water lends importance to the area because habitat for wildlife is composed of food, cover, water, and space. Riparian areas offer one of these critical components, and often all four.

2. The greater availability of water to plants, frequently in combination with deeper soils, increases the production of plant biomass and provides a suitable site for plants that are limited elsewhere by inadequate water. The combination of these factors leads to increased diversity in the species of plants and in the structural and functional diversity of the biotic community.

3. The dramatic contrast between the complex of plants in the riparian area with that of the general surrounding vegetation of the upland forest or grassland adds to the structural diversity of the area. For example, the bank of a stream that is lined with deciduous shrubs and trees provides an edge of stark contrast when surrounded by coniferous forest or grassland. Moreover, a riparian area dominated by deciduous vegetation provides one kind of habitat in the summer, when in full leaf, and another type of habitat in the winter, following leaf fall.

4. The shape of many riparian areas, particularly the linear nature of streams and rivers, maximizes the development of edge effect, which, under the right conditions, is so productive in terms of wildlife.

5. Riparian areas, especially those in coniferous forests, frequently produce more edges within a small area than would otherwise be expected based solely on the structure of the plant communities. In addition, many strata of vegetation are exposed simultaneously in stairstep fashion. This stairstepping of vegetation of contrasting form (deciduous versus coniferous, or otherwise evergreen, shrubs and trees) provides diverse opportunities for feeding and nesting, especially for birds and bats.

6. The microclimate in riparian areas is different from that of the surrounding area because of increased humidity, a higher rate of transpiration (loss of water) from the vegetation, more shade, and increased movement in the air. Some species of animals are particularly attracted to this microclimate.

7. Riparian areas along intermittent and permanent streams and rivers provide routes of migration for wildlife, such as birds, bats, deer, and elk. Deer and elk frequently use these areas as corridors of travel between high-elevation summer ranges and low-elevation winter ranges.

8. Riparian areas, particularly along streams and rivers, may serve as forested connectors between forested habitats or elevational habitats, such as grasslands. Wildlife may use such riparian areas for cover while traveling across otherwise open areas. Some species, especially birds and small mammals, may use such routes in dispersal from their natal habitats. This may be caused by the pressures of overpopulation or by shortages of food, cover, or water. Riparian areas provide cover and often provide food and water during such movements.2

In addition, riparian areas supply organic material in the form of leaves and twigs, which become an important component of the aquatic food chain. Riparian areas also supply large woody debris in the form of fallen trees, which form a critical part of the land/water interface, the stability of banks along streams and rivers, and instream habitat for a complex of aquatic plants as well as aquatic invertebrate and vertebrate organisms.3

Setting aside riparian areas as undeveloped open space means saving the most diverse, and often the most heavily used, habitat for wildlife in proximity to a community. Riparian areas are also an important source of large woody debris for the stream or river whose banks they protect from erosion.4 Furthermore, riparian areas are periodically flooded in winter, which, along with floodplains, is how a stream or river dissipates part of its energy. It is important that streams and rivers be allowed to dissipate their energy; otherwise, floodwaters would cause considerably more damage than they already do in settled areas.

FLOODPLAINS

A floodplain is a plain that borders a stream or river that is subject to flooding. Like riparian areas, floodplains are critical to maintain as open areas because, as the name implies, they frequently flood. These are areas where storm-swollen streams and rivers spread out, decentralizing the velocity of their flow by encountering friction caused by the increased surface area of their temporary bottoms, both of which dissipate much of the floodwater’s energy.

It is wise to include floodplains within the matrix of open spaces for several other reasons: (1) they will inevitably flood, which puts any human development at risk, regardless of efforts to steal the floodplain from the stream or river for human use (witness the Mississippi River); (2) they are critical winter habitat for fish;5 (3) they form important habitat in spring, summer, and autumn for a number of invertebrate and vertebrate wildlife that frequent the water’s edge;6 and (4) they can have important recreational value.

Consider, for example, the people who originally moved into Washington’s Puget Sound trough, Oregon’s Willamette Valley, or California’s Central Valley. In those bygone times, people lived on and farmed the land in concert with the rivers, including their periodic floods, because they knew where the floodplain was and respected it. However, it has long been American tradition to wrest every useable acre from Nature, lest an acre be thought of as “unproductive.”

If the rivers could be controlled and the flooding stopped, then more “unproductive” acres could be made to produce that which Americans thought desirable. Enter the U.S. Army Corps of Engineers, which, by the year 2000, had grown from modest origins as a Revolutionary War regiment in George Washington’s army, with an initial budget of $75,000, into a $12 billion Pentagon behemoth with 37,000 employees. The Corps is one of the oldest, largest, and most unusual agencies in the federal government.

As a bureaucracy of the executive branch, which takes its marching orders from Congress, it is a military organization with an overwhelmingly civilian workforce. It is also an environmental regulator that is despised by environmentalists because members of Congress often authorize projects to steer federal money to their districts, and the Corps often justifies them with questionable cost/benefit analyses, and in the process has reconfigured—engineered—the American landscape. After all, its motto is Essayons, which is French for “Let us try.” The motto indicates that, throughout its history, the Corps has seen Nature as an enemy to subjugate by equating engineering and control with social progress.

Almost all modern presidents have clashed with the Corps over its behavior and environmental insensitivity—and the Corps has usually won. Presidents Roosevelt, Truman, Johnson, and Nixon all considered reforms, which ultimately were defanged. In 1977, President Carter tried to kill nineteen water projects; he not only failed but also permanently damaged his relationship with Congress. Although President Reagan did manage to force Congress to make local communities pay more for Corps projects, the exchange rate for the American people was a new round of costly projects. President Clinton also lost to the Corps.

The Corps’ pro-construction attitude is mixed with the military-engineering mentality, which is not only based on force-oriented solutions, where Nature is the enemy, but also justified by a narrow worldview. “The Corps still doesn’t get it,” contends Bill Hartwig, a regional director of the U.S. Fish and Wildlife Service. “They still think they can defeat Mother Nature with brilliant engineering. They talk about the environment, but they don’t really believe it.”7

For instance, the Corps of Engineers designs and builds structures to control flooding and to improve navigation, but it also issues permits for the alteration of such bodies of water as streams, rivers, marshlands, and estuaries. Although the Corps leaders speak of “working in harmony with nature,” the Corps still proudly mobilizes its “Annual Campaign Against the Mighty Mississippi.” This on-going battle caused Burton Kemp, a former Corps geologist in Mississippi, to say it is not surprising when the Corps takes a militaristic approach to the environment. “I’m afraid it’s not a Corps of Scientists. It’s not a Corps of Biologists,” he says with a sigh. “It’s a Corps of Engineers.”8

Moreover, internal memos show that Corps commanders, who have launched a Corps-wide campaign to “seek growth opportunities,” have fueled this pro-construction attitude. The campaign’s outcome is a nation-wide, fragmented network of channelized, riprapped, levee-bound, and dammed streams and rivers; drained wetlands; and deepened ports. This conglomerate is cobbled together through deal-cutting lawmakers seeking federal money to appease their constituents at election time—instead of being a transparent, comprehensive planning process that involves personnel from both state and federal agencies concerned with social-environmental sustainability.9

Let’s look at just four possible choices people could have made prior to a major flood like that of 1996/1997 in California’s Central Valley.10 The choices are: (1) do not live or farm in the floodplain; (2) live and farm in the floodplain without dams and levees and plan for, be prepared for, and accept the risk of periodic flooding; (3) live and farm in the floodplain with dams and levees in place, thinking the problem of flooding is solved, but move after a levee breaks once or twice; (4) live and farm defiantly in the floodplain with dams and levees in place, regardless of the dire consequences of periodic flooding.

All of these choices represent different levels of self-imposed constraints on one’s own behavior based on different perceived values for monetary gain and lifestyle. The choice that seems to have been generally accepted over time is the last one: live and farm defiantly in the floodplain regardless of consequences. This, then, becomes the primary social constraint or “fixed point” around which all human residential, rural, and commercial development is made to revolve, despite the fact that sooner or later the rivers will remember their floodplains and reclaim them—at least temporarily, and at great cost to the thieves.

So dams and levees ae constructed. If they failed to produce the desired control, more dams and levees are built. In the end, however, they are proving no match for Nature. But there is something left unsaid here, namely that the choices people make.

People then build in the floodplain, but when their irresponsible risk taking fails, they want the government (hence society at large) to bail them out—despite fact that building in a floodplain is not only ill-advised but also has inevitable consequences. Why, I wonder, should the American public, through personal taxes paid to the government, be expected to bail out those individuals who make unwise choices when they gamble for such high stakes? Do we, through taxes paid to the government, bail people out of financial trouble when they loses heavily in a high-stakes game of craps in a casino in Las Vegas? Building in a floodplain and wagering in a game of craps are both gambling, so what’s the difference? Where is personal responsibility? How is one to learn responsibility if one does not have to accept the full measure of the consequences of one’s choices?

It is was not always this way, however, said Scott Faber, director of floodplain programs for American Rivers, based in Washington, D.C. According to Faber, “Floods may be acts of God, but flood losses are acts of hubris.”11 Predictable, natural events, such as floods, have turn into natural disasters when people try to control streams and rivers with dams and levees because housing and commercial development have flooded the floodplains.

“At the turn of the century,” writes Faber, “there was virtually no development in floodplains. Over the last [70 some] years, government programs have assumed responsibility for flood ‘control’ by building and repairing levees, providing relief, and subsidizing flood insurance. These programs actually put people in harm’s way by eliminating incentives for local communities to direct new development away from flood-prone areas.”12

Here the challenge is that levees and dams create a false sense of security, which encourages people to build in flood-prone areas and thus increases the potential for catastrophe when a levee inevitably fails. Thus, thousands of flood-weary Midwesterners decided in 1993 to stop “playing chicken” with the Mississippi and Missouri rivers. They opted instead for a new voluntary program that relocated more than 8,000 homes and businesses, even whole towns, onto the bluffs, so that thousands of people were literally high and dry when floodwaters returned in 1995.

As development continually encroaches on floodplains, the rainfall that once was slowly and naturally absorbed by the land now gushes into drainage ditches, streams, and rivers, which only get higher and faster as they flow downstream toward centers of human population with ever-greater velocity —the inevitable effect of their waters being constrained by dams and levees. An isolated decision to drain a wetland, till a farm, pave a parking lot, put in a new street, or construct a housing project has little measurable effect on flooding itself, but when combined with the unseen tyranny hidden in thousands of other seemingly unrelated decisions, the cumulative effect can be devastating.

Rather than work together to solve regional problems, most communities and rural landowners simply pass the water downstream as fast as possible. The problem, cause by dams and levees in the first place, cannot be fixed with more dams and levees—but the latter can ensure prolonging the problem by passing the flooding downstream to even more densely populate areas. Periodic flooding, at times of mammoth proportions, is one of Nature’s non-negotiable constraints, especially during cool, wet periods in the weather cycle, which heretofore has been another of Nature’s non-negotiable constraints. Hence, a wise community will both recognize and bow to Nature when Nature is beyond its control. After all, Nature always trumps our human gamble when we contest the rules of engagement in dealing with a non-negotiable constraint.


Related Posts:

• Why Be Concerned With The Building Blocks Of Sustainable Planning

• The Negotiability Of Constraints

• Feedback Loops

• Of Human Relationships And Social-Environmental Sustainability

• Grieving For Our Environmental/Social Losses

• Transportation—Efficiency Or Effectiveness, A Choice Of Focus

• Is Space A Resource?

• Open Space—A Biophysical And Cultural Necessity

• An Urgent Plea For Open Space

• Surrounding Landscape

• Restoration Of A Specific Condition Is Not Possible


ENDNOTES

  1. The preceding discussion about restoring part of the Snake River to a more natural condition is base on:  Jim Robbins. Engineers Plan to Send a River Flowing Back to Nature. The New York Times, New York, NY. May 12, 1998.
  2. Jack W. Thomas , Chris Maser, and Jon E. Rodiek. Riparian Zones. Pp. 40-47. In: Wildlife Habitats in Managed Forests—The Blue Mountains of Oregon and Washington. USDA Forest Service, Agricultural Handbook No. 553 (Jack W. Thomas, Technical Editor). U.S. Government Printing Office, Washington, D.C. 1979.
  3. Chris Maser and James R. Sedell. From the Forest to the Sea:  The Ecology of Wood in Streams, Rivers, Estuaries, and Oceans. St. Lucie Press, Delray Beach, FL. (1994) 200 pp.
  4. Ibid.
  5. Ibid.
  6. Ibid.
  7. The discussion of the U.S. Army Corps of Engineers is based on: (1) Jim Robbins. Engineers Plan to Send a River Flowing Back to Nature. The New York Times. May 12, 1998; (2) Michael Grunwald. The corps’ divided mission. LA Times-Washington Post Service. In: The Oregonian, Portland, OR. February 17, 2000; (3) Michael Grunwald. More powerful than a river. The Washington Post. In: Albany (OR) Democrat-Herald, Corvallis (OR) Gazette-Times. November 23, 2000; (4)Frederic J. Frommer. Groups identify ‘wasteful’ Corps water projects. The Associated Press. In: Corvallis Gazette-Times, Corvallis, OR, March 3, 2000; and (5) Amalie Young. Court:  Snake dam operation violates Clean Water Act. The Associated Press. In: Corvallis Gazette-Times, Corvallis, OR, February 17, 2001.
  8. Michael Grunwald. An Agency of Unchecked Clout. The Washington Post. September 10, 2000.
  9. Michael Grunwald. The corps’ divided mission. LA Times-Washington Post Service. In: The Oregonian, Portland, OR. February 17, 2000.
  10. (1) John Howard. Crews struggle to save California levees. The Associated Press. In: Corvallis Gazette-Times, Corvallis, OR. January 7, 1997; (2) Matthew Yi. Brimming reservoirs keep California flood threats alive. The Associated Press. In:Corvallis Gazette-Times, Corvallis, OR. January 10, 1997; (3) John Howard. Receding floodwaters reveal fields of dead cows, horses. The Associated Press. In: Corvallis Gazette-Times, Corvallis, OR. January 10, 1997; and (4) The Associated Press. Levy failure causes new floods in California. In: Corvallis Gazette-Times, Corvallis, OR. January 11, 1997.
  11. Scott Faber. Get people off of nation’s floodplains. Corvallis Gazette-Times, Corvallis, OR. January 21, 1997.
  12. Ibid.

© Chris Maser, 2009. All rights reserved.

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