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What is “natural?” lessons learned in applying context sensitive design to stream restoration and mitigation project development
Kelley Jorgensen, URS Corporation
Jeremy Sikes, URS Corporation
Anne MacDonald, URS Corporation
Doug Sovern, URS Corporation
Jorgensen K, Sikes J, MacDonald A and Sovern D. 2006. What is “natural?” lessons learned in applying context sensitive design to stream restoration and mitigation project development. IN: Proceedings of the 2005 International Conference on Ecology and Transportation, Eds. Irwin CL, Garrett P, McDermott KP. Center for Transportation and the Environment, North Carolina State University, Raleigh, NC: pp. 677-678. (Abstract)
ABSTRACT: Instream projects—whether for habitat enhancement, culvert and bridge replacements, mitigation for fisheries or
aquatic habitat impacts, or bank protection—often occur in altered streams in altered watersheds. For this paper,
we will use the term “enhancement” to include all forms of “restoration” and “rehabilitation.” Infrastructure typically
interrupts watershed geomorphic processes and places constraints from both physical and legal liability viewpoints.
Stakeholders can bring constraints in the form of biased perceptions and interests. Raw materials that may have
been historically available for habitat-forming features are likely greatly reduced or even wholly unavailable to the
stream, especially lower in the watershed. As a result, these natural materials can be unavailable to sustain or
construct enhancement projects, or conversely, may be available to excess. While we often recognize that watersheds
are altered, we frequently do not apply that information in the context of individual project development and
implementation. As a result, inappropriate project design results from a lack of consideration of the entire project
context (both project and watershed scale) and from circumventing a detailed constraints analysis early in the process.
Practitioners often try to improve instream and riparian habitats with the goal of restoring “natural” functions without
recognizing the larger context of the existing altered conditions in the watershed. This nearly ubiquitous state of alteration
requires us to recognize that the altered state of urban, and even many wildland streams, is unlikely to support
historic habitat functions without structural intervention. Elements that formed instream habitat in the undisturbed
stream may not work or may require adaptation in the new urban or disturbed environment. If “natural” defines the
undisturbed stream, the obvious question is how “non-natural” do our design options need to be in the new urban or
disturbed environment?
Our interdisciplinary design team and project management approach mirrors most of what defines the Context
Sensitive Design (CSD) approach. We find that CSD applies a balanced approach in order to maximize natural, selfsustaining,
low-maintenance elements that provide more long-term habitat functions, while still realizing the immediate
creation or enhancement of missing habitats to provide needed functions to keep imperiled species viable. We share
a common goal to create successful, natural, and self-sustaining stream-enhancement project designs that contribute
to species and ecosystem recovery. This approach is usually more acceptable to the regulatory and environmental
community. We are able to apply the reliability and stability of engineered features that may best provide short-term
habitat functions, while larger-scale natural processes are allowed to re-establish.
We have identified a list of project and watershed elements that define project context as it relates to CSD and stream
enhancement projects. Project context goes beyond site-specific or watershed condition assessment to include:
• Regulatory drivers, expectations and requirements
• Temporal constraints and goals, (short-term and long-term functions and processes)
• Physical/spatial constraints and goals, including landowners and infrastructure
• Liability considerations
• Cost
• The scope and scale of multi-level planning processes and stakeholder involvement.
We will compare the risks and benefits of different project approaches (CSD versus traditional) relative to ecological
processes and professional liability. We will discuss natural vs. engineered/non-natural adaptations and new
components in terms of:
• Long-term vs. short-term habitat functions and processes
• Symptoms vs. root problems
• Techniques/methods/materials
• Perceptions of stakeholders applied to all of the above
We will present project case studies in the Lower Columbia and Willamette River basins in Washington State and
Oregon. Some interesting differences will be noted that resulted from both applying CSD early on, versus applying
CSD late in the design process. These projects will illustrate ways to identify and define the watershed and project
Poster Presentations 678 ICOET 2005 Proceedings context, prioritize structural and non-structural project elements, and develop and choose from a toolbox that includes
the maximum range of methods, techniques, materials, and approaches. We will address pre- and post-project
monitoring as a critical (but often overlooked and underfunded) element in the successful adaptive management of
dynamic resources. Finally, we will reaffirm the message that CSD has great applicability in the future development and
prioritization of stream- and river-enhancement projects to improve the success of species and ecosystem recovery on
a large scale.
CITATION: Jorgensen K, Sikes J, MacDonald A and Sovern D. 2006. What is “natural?” lessons learned in applying context sensitive design to stream restoration and mitigation project development. IN: Proceedings of the 2005 International Conference on Ecology and Transportation, Eds. Irwin CL, Garrett P, McDermott KP. Center for Transportation and the Environment, North Carolina State University, Raleigh, NC: pp. 677-678. (Abstract)
Road Ecology Center.
Paper Jorgensen2005a.
http://repositories.cdlib.org/jmie/roadeco/Jorgensen2005a
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