2008 BES Annual Meeting Presentation and Poster Abstracts
The engineered “karst” of urban landscapes and their constraints on water quality and urban stream ecosystems.
Co-Authors: W. P., Stack, C. Welty, S. S. Kaushal, and P. M. Groffman
Abstract: Urban streams have long been known to have poor water quality due to stormwater runoff and sewer/illicit connections. However, understanding how these impacts modulate aquatic ecosystems requires a highly interdisciplinary, multi dimensional approach. Just as aquatic ecologists have come to realize the importance of hyporheic and watershed influences on stream ecological structure and function, we are realizing that urban systems are not simply runoff conveyance systems, but affect streams at an additional level of complexity. Of great importance is the degree of connectivity between civil infrastructure and urban streams, which goes far beyond the routing of stormflow and includes flow augmentation by potable water networks as well as upland and riparian influences from sanitary sewers. Almost every hectare of the urban landscape is underlain by this dense network of pipes which create a kind of “engineers karst” which not only affects hydrologic processes, but creates a previously under-appreciated “gutter subsidy” for organic matter and other material to urban streams. Moreover this extension of the stream network extends to almost every drainage feature in the landscape, essentially making every gutter and rooftop a zero order stream. We will discuss various aspects of these extreme terrestrial-aquatic linkages and how they relate to the ecology of streams.