Urban Riparian Zones: Designing Mitigation Buffers

摘要

Larger-scale mitigation practices, such as through the establishment of mitigation banks, have become common as a means to offset the land disturbance that urban development (e.g., big box store construction) is associated with. While stronger stormwater detention systems have helped control the amount of urban runoff, they do not resolve the larger problems of stormwater pollution and the TMDL impact upon receiving waters in the urban environment. Riparian buffers offer an economical, customizable, low maintenance solution for the improvement of stormwater quality and runoff reduction. Drawn from established practices in watershed management and restoration, urban riparian buffers can be efficiently scaled to sites of various sizes (with wider buffer zones offering greater impact). Their benefits are many, including increased infiltration rates, lower TMDLs to urban water structures, a measurable decrease in stormwater pollutants flowing to receiving waters, the creation of native habitat for migratory species, and aesthetic design solutions (such as disguising buffers as parks). From the management of stormwater at a new shopping plaza to the creation of waterfront redevelopments, urban riparian buffers also offer unique educational opportunities for the public on the benefits and challenges of stormwater directly where they live and work. This paper will examine the beneficial and measurable impacts that these riparian buffers can have on stormwater quality and the minimization of non-point source pollution on surface and groundwater quality. The paper will also explore responsible design strategies for establishing riparian buffers. A particular emphasis will be placed on securing healthy vegetation, as long-term vegetation is the most effective way to keep urban stormwater directly in its environment. The importance of tree shelters will t highlighted for their success in large-scale mitigation (e.g., Chesapeake Bay Watershed restoration) an small-scale riparian buffer designs that reduce mitigation needs. Tree shelters help vegetation conserv water and protect against damage (animal, chemical, mechanical) over their critical years of root and growth establishment. They are also easy for land managers to monitor, adjust, and remove, and they enable considerable customization of vegetation for the creation of native and aesthetic vegetation buffers, as well as improved project economics. Various urban case studies will be included and current research summarized.