Baltimore Ecosystem Study Institute of Ecosystem Studies

2011 BES Annual Meeting Presentation and Poster Abstracts

Ultra-urban baseflow and stormflow concentrations and fluxes in a watershed undergoing watershed restoration (WS263).
Belt, Ken
Co-Authors: Belt, K.T., Stack, W.P., Pouyat, R., Burgess, K., Groffman, P.M. and Kaushal, S.S.

Abstract: Watershed 263 is an ultra-urban landscape in west Baltimore city that is the site of comprehensive watershed restoration efforts. We discuss the high baseflow and stormwater concentrations of nutrients and sulfates seen in two 15 ha headwater stormdrain subcatchments sampled ca. 2004-2010. We also present preliminary concentration and loading results. In the "Balt" catchment, half or more of the load for SO4, NO3-N, TN, PO4-P and TP was carried in the baseflow load, whereas in the "Lanv" catchment these were smaller carried only by stormwater runoff, suggesting that in Balt there may be inputs of sewage. The Balt average annual load was much greater than for Lanv (e.g., for TN, 57 vs 6.1 kg/ha/yr), due to the lack of a large Lanv baseflow load and unexplained low rainfall-runoff ratios there. The Balt TN and TP loads were much greater than loads previously measured for suburban, forested and agricultural small streams in the BES network, e.g., for TN by factors of 6.3, 28.6, and 1.5 respectively. The Balt catchment is a "hot spot", generally with loads that resembled those of an agricultural watershed more than a suburban watershed. Balt concentrations and loads in the latter part of the record (2004-2006 vs.2007-2010) decreased for all constituents, by about one third to two thirds, far in excess of load reductions expected from stormwater runoff BMPs suggesting a complicated hydro-chemical system in which groundwater plays an important role with large changes over time.