Time series of tracer (Rhodamine WT) concentration data representing a "break-through curve" resulting from a single, multi-scale tracer test conducted along the length of Lookout Creek, from its 2nd-order headwaters through its 5th-order main stem. The longitudinal tracer test involved an in-stream injection of Rhodamine WT over 78 hrs, followed by monitoring at eight downstream locations for five months, starting in mid-June 2003 through the middle of November 2003. The injection site was located below the upper Old Growth Trail bridge. The monitoring sites include one downstream of the injection site, above and below the Cold Creek confluence, below the lower Old Growth Trail bridge, below Mack Creek confluence, above and below McRae Creek confluence, and at the HJA headquarters. Three additional inter-order tracer tests (IOTT) were carried out between each of the major stream confluences along Lookout Creek. The injection site for the McRae Creek IOTT was located below the McRae Cr. confluence and was monitored just downstream, at the end of the main floodplain, and at HJA headquarters. The injection site for the Mack Creek IOTT was located below the Mack Cr. confluence and was monitored just downstream, at an unnamed tributary midway between Mack Cr. and McRae Cr., and above the McRae Cr. confluence. The injection site for the Cold Creek IOTT was located below the Cold Cr. confluence and was monitored just downstream, at Longer Cr., and at the lower Old Growth Trail bridge. Concentration break through curves are available for all of the monitoring sites for the longitudinal and inter-order tracer tests. Flux break through curves are available for most of the monitoring sites. STAMMT-L model estimates for hyporheic exchange is listed for most of the monitoring sites.
Jeffery J. Ninnemann, Michael N. Gooseff, Roy Haggerty, Steven M. Wondzell
The primary goal of this research project is to quantitatively measure the temporal scales of hyporheic exchange along a stream network. Our goal is to examine how hyporheic exchange varies with increasing stream size. Many previous studies focus on single stream reaches or on several reaches of similar sized streams, whereas we examined the residence time of water in the hyporheic zone over increasing length scales in a single stream. Prior work with tracer data and analysis using a transient storage model with an exponential residence time distribution (RTD) suggests that hyporheic parameters, primarily volume and mean residence time, are both spatially and temporally scale-dependent. However, recent work hypothesizes that the scale-dependence may be partially addressed by using a power-law RTD (Haggerty et al., 2002). Our research tests this hypothesis with several multi-scale tracer tests in a single stream.