DOI: 10.6073/pasta/5f15b7aa8d3f57d9e05a0392c6f57749
title: Baltimore Ecosystem Study: Stream chemistry for Gwynns Falls Upper Tributaries

description: In the Baltimore urban long-term ecological research (LTER) project,
 (Baltimore Ecosystem Study, BES) we use 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 several 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).
 Each of the gaging sites is continuously monitored for discharge and
 is sampled weekly for chemistry. Additional chemical sampling is
 carried out in a supplemental set of sites to provide a greater range
 of land use. Weekly analyses includes nitrate, phosphate, total
 nitrogen, total phosphorus, chloride and sulfate, total suspended
 solids, turbidity, fecal coliforms, temperature, dissolved oxygen and
 pH. Cations, dissolved organic carbon and nitrogen and metals are
 measured on selected samples.

 
 This dataset presents stream chemistry from the Upper Gwynns Falls
 tributaries. From April 1999 to August 2000 Johns Hopkins University
 graduate student Mark Colosimo sampled a group of sites in the Upper
 Gwynns Falls (Red Run, Horsehead Branch, Scotts Level Branch, Holly
 Branch). There were two sites in the Red Run drainage. This watershed
 drains approximately 19 km2 and has been rapidly suburbanizing since
 the early 1990s. Percent impervious surface was approximately 10% as
 of 2002. Sampling station Red Run 1 (RR1) was approximately 35 m
 upstream of the crossing of Painters Mill Bridge Road, and 350 m
 upstream of the confluence with the Gwynns Falls. Sampling station Red
 Run 2 (RR2) was farther upstream, between the Pleasant Hill and
 Dolfield road crossings. There were two sites along Scotts Level
 Branch, an older suburban watershed which was approximately 25%
 impervious surface in 1970. Site SL1 drains approximately 11 km2 and
 is located at the outlet of the sub-watershed, just above the
 confluence with Gwynns Falls. Site SL2 is at the McDonogh Rd. bridge
 crossing. The Horsehead Branch (HH) sampling site was located at the
 McDonogh Road crossing. It drains approximately 5 km2 that has
 undergone rapid urbanization since the mid 1980s. As of 1997 percent
 impervious surface was approximately 12%. The Holly Bank (HB) sampling
 site was located just upstream of Gwynnbrook Ave. Seventy percent of
 land in this drainage is classified residential. The Gwynns Falls at
 McDonogh (GF5) site was located at the McDonogh school / McDonogh road
 crossing of the Gwynns Falls and samples a drainage area of
 approximately 51 km2, with approximately 20% impervious surface.