| Popis: |
We discuss the results of sampling baseflow and stormwater runoff in Watershed 263, an ultraurban catchment in west Baltimore City that is undergoing restoration aimed at both improving water quality as well as the quality of life in its neighborhoods. We focus on urban hydrology and describe the high baseflow and stormwater nutrient, metal, bacterial and other pollutant concentrations and loads seen in two 15 ha headwater storm drain catchments within WS263 that were sampled from 2004 to 2010. These data revealed several potentially important implications for watershed restoration efforts. First, the underground, or “buried stream” baseflow loads can be substantial, even relative to the surface urban runoff loads in highly impervious urban catchments. Second, the large pollutant load exports from these residential catchments suggest that older, highly urban landscapes may be important hotspots, as these small headwater catchments are numerous in the urban landscape. Third, the complex nature of the pollutant export patterns at the Baltimore and Lanvale catchments, both spatially and temporally, suggest that there may be complex drivers involved. Since this complexity may involve one or more systems of urban water networks, conceptualization in terms of the Urban Watershed Continuum (Kaushal and Belt, 2012) may be a useful tool to use both in their characterization and in designing interventions. Lastly, if these small headwater catchments truly represent a larger typology in terms of being hotspots, the characterization and mapping of older ultra-urban catchments may well be worthwhile given the large numbers of potential analogues in the urban landscape and the likely increasing role of aging infrastructure in creating more and larger “unseen” pollutant loads. |
