Stream Restoration

The urban landscape poses unique challenges to scientists charged with restoring the biological and physical stability, or equilibrium, of stream systems impacted by natural and developmental changes. Unlike streams in rural settings, urban streams often suffer from a combination of physical and hydraulic impacts associated with extensive paving and land development, stormwater management, and channel straightening. A stream responds to such environmental changes by altering its plan form profile and cross section, seeking equilibrium in flows and sediment transport. In some cases, the system’s biological functions become degraded as the stream compensates for new inputs.

Setting realistic goals for restoring stream systems requires a thorough understanding of a site’s unique characteristics and the interplay of engineering, biological, construction, social, legal, and cost factors.

KCI scientists assess a variety of factors in three major categories of analysis that provide a roadmap for establishing project objectives. First, in determining the degree to which a stream can be enhanced to meet geomorphological objectives, KCI looks at physical issues, such as the presence of utilities, flooding, adjacent land use, ownership, construction access, and bank stabilization. Second, in assessing a stream’s potential physical and biological functions, KCI scientists study the quality of water entering the site, hydrology and hydraulics, and the potential for long-term local support. The third category involves price. Despite the availability of cutting-edge technology, the cost associated with the stream’s length, size, and complexity is often the deciding factor in determining environmental design solutions. At the point where cost exceeds the derived benefit, a client may seek other approaches.

No magic formula exists for determining how any one factor will impact a project. Firsthand experience is often the best teacher when navigating through the sometimes confusing maze of issues that surround environmental projects. Understanding a system’s limitations is the key to making informed decisions, selecting approaches that will provide the highest return in functionality, and ensuring that project expectations will mesh with system realities.

 

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