Stream and Watershed Studies - Overview
Water quality in urban ecosystems has been relatively well studied, with a strong focus on the effect of storm runoff of receiving water quality. However, the vast majority of these studies have been short-term and focused on storm events. There have been very few attempts to evaluate long-term nutrient fluxes and budgets in urban watersheds similar to the approach taken in long-term ecological research. Long-term flux and budget studies are necessary if we hope to be able to compare urban ecosystems with the less intensively managed ecosystems that dominate the LTER network. Such studies should also provide a useful and unique addition to the database on pollutant delivery to receiving waters in urban watersheds.
In the Baltimore urban LTER, we are using the watershed approach to evaluate integrated ecosystem function. The LTER research is centered on the Gwynns Falls watershed, a 17,150 ha catchment that traverses a gradient from the urban core of Baltimore, through older urban residential (1900 - 1950) and suburban (1950- 1980) zones, rapidly suburbanizing areas and a rural/suburban fringe. Our long-term sampling network includes four longitudinal sampling sites along the Gwynns Falls as well as four small (40 - 100 ha) watersheds located within or near to the Gwynns Falls. The longitudinal sites provide data on water and nutrient fluxes in the different land use zones of the watershed (rural/suburban, rapidly suburbanizing, old suburban, urban core) and the small watersheds provide more focused data on specific land use areas (forest, agriculture, rural/suburban, urban).
The effects of land use/land cover patterns, hydrologic flowpath structure and dynamics and the presence and distribution of BMPs are evaluated relative to the behavior of the set of sampled catchments. The set of catchments along the urban-rural gradient are compared within our network and with other catchments in the LTER network.
In addition to our long-term stream monitoring, there is BES research on stream biotic communities.