|Little Topashaw Creek - Size and organic matter content of channel bed material
?Bed material samples were collected from the channel of Little Topashaw Creek in September 1999 and in August 2003 at five transects located at ~500 m intervals along the rehabilitation reach. Sample locations for 1999 and 2003 were similar. Three samples, each 3-4 kg, were collected from each transect using a small shovel. The first was a composite (right, middle, and left) from the baseflow channel, while the other two represented right and left bank bar accretions. Each sample was placed in a plastic bag and returned to the laboratory for sieve analysis.
?Samples of the top 10 cm of hyporheic zone sediments, including organic matter lying on the bed surface, were taken from channel transects during base flow in June 2000 just prior to construction and in July-August 2003. At each transect, ~250 g samples were taken from the channel centerline and from the region between edge and the quarterpoint of the base flow channel. Visual descriptions of the samples and stream characteristics were recorded at each transect. In 2000 and again in 2003, Samples were collected from the same 39 cross sections used for channel surveys located along the 2 km study reach. In 2003, 9 transects upstream and 18 transects downstream of this reach were also sampled. The upstream sample sites were selected to characterize the contributing watershed, while the downstream sites were located along a channelized reach influenced by backwater conditions due to a major sediment and debris plug.