HR: 12:05h
AN: H22B-07    [Abstracts]
TI: Physical Controls of Solute Transport and Storage in Indian Creek, an Urban Stream
AU: * Ryan, R J
EM: rjryan@temple.edu
AF: Temple University, Department of Civil and Environmental Engineering 1947 N 12th St, Philadelphia, PA 19122 United States
AU: Boufadel, M C
EM: boufadel@temple.edu
AF: Temple University, Department of Civil and Environmental Engineering 1947 N 12th St, Philadelphia, PA 19122 United States
AB: Conservative solute tracer experiments are commonly used to estimate transient storage characteristics of relatively pristine streams. However, when combined with field-based data on stream morphology and sediment characteristics, one can reasonably determine not just the transport and storage characteristics, but also which processes control transport and storage in a given stream. This additional information is useful in urban streams undergoing relatively fast geomorphic and hydrologic changes. We conducted a conservative solute tracer experiment in Indian Creek, a small urban stream located in Philadelphia, Pennsylvania. As part of the experiment, we first surveyed the stream topography at a 1m resolution. During the tracer experiment, in addition to monitoring the surface water, we sampled bankside wells and small diameter wells installed in the wetted channel and in a large gravel bar. Post-experiment, we measured in situ streambed hydraulic conductivity using a portable permeameter. From our results we were able to determine that the hyporheic zone extends vertically more than 7.5 cm below the streambed and laterally as much as 8 m from the wetted channel. In addition, we found that our data from the in-channel wells yielded a strong linear relationship between the surface-subsurface tracer flux (mgL^-1min^-1) and hydraulic conductivity (cms^-1). Finally, the observed tracer concentration in the bankside wells appeared to be related to stream curvature with higher concentrations found along the outside and lower concentrations found along the inside of stream bends. Based on our data, we conclude that 1) hyporheic exchange was a significant component of solute transport and storage in the urbanized Indian Creek and 2) hyporheic exchange was controlled by a combination of hydraulic conductivity and stream morphology.
DE: 1824 Geomorphology: general (1625)
DE: 1830 Groundwater/surface water interaction
DE: 1834 Human impacts
DE: 1861 Sedimentation (4863)
DE: 1879 Watershed
SC: Hydrology [H]
MN: Fall Meeting 2005