Streamlab 2006

StreamLab06 was a multiphase research endeavor involving academic researchers, federal agencies and stream restoration practitioners. This ongoing project is being conducted in the Main Channel at the St. Anthony Falls Laboratory in Minneapolis, MN. The StreamLab program brings together a spectrum of research expertise (stream ecology and biology, engineering, hydrology, hydraulics and geomorphology) to conduct focused studies on a laboratory controlled, field scale, indoor stream environment.

The first phase of the StreamLab06 project was completed in late March, 2006, and was focused on testing several existing and one new technology for sampling bedload transport. Technologies were tested in separate sets of sand and gravel trials. 

For the former, the channel was pre-loaded with sediment consisting of nearly uniformly sized (approximately 0.8mm) sand. Transported sand was captured in the channel's weigh pans, weighed, and recirculated. The water discharge varied (from trial to trial) between 2.0 and 3.6 cubic feet per second. 

Three standard "manual" samplers were tested: a 3" Helley-Smith, a 3" BL84 and an Elwha Sampler. For each, samples were taken at a fixed lateral position in the flow, just upstream from the weigh pans. Samples were taken over times varying from 15 seconds to one minute to see what sample-time would be necessary to capture natural variability in the sediment transport. 

In addition to these samplers, two (1200 and 600 kHz) Acoustic Doppler Current Profilers (ADCP) were installed and tested. These units just touch the water surface, and have the potential to deliver non-destructive information on sediment transport. For this experiment, researchers concentrated on the zones just upstream and downstream of the unit. In the downstream zone, which was just upstream of the weigh pans, a velocimeter (16mHz Micro ADV) provided a velocity profile of the flow, which will be used to calculate bed stresses. Finally, a 100 frame-per-second digital video camera capable of resolving individual grains captured the flow as it passed through the downstream zone. 

For the second set of trials, the sand was cleared from the channel, replaced with gravel, and several runs with varying discharges (up to a maximum of 5.5 cubic meters per second) were conducted. The same bedload sampling technologies were in place for the gravel runs, and a Toutle River 2 sampler was added to the mix.