Dudley W. Reiser

Status of Instream Flow Legislation and Practices in North America

Abstract This paper presents the results of two nonstatistical surveys (completed in 1981 and 1986) that solicited information from state and federal agencies concerning instream flow issues and practices in North America. Forty-six states and 12 Canadian provinces responded to the survey. Fifteen of the 46 states reported legislative recognition of instream flows for fisheries protection. In Canada, individual provinces generally lacked instream flow legislation, although federal legislation existed that could be used. The most commonly applied method (in use in 38 states or provinces) for assessing instream flow requirements, as reported in the survey, was the Fish and Wildlife Service Instream Flow Incremental Methodology (IFIM). Major research needs cited by survey respondents included (1) more species habitat information and preference curves, (2) techniques for determining instream flows for atypical conditions, and (3) testing of fish habitat:flow: production relationships.

New Technique for Measuring Fine Sediment in Streams

Abstract Techniques commonly used to measure fine-sediment accumulation in streambed gravels can be labor and equipment intensive. We evaluated the sediment trapping capabilities of modified Whitlock–Vibert boxes under both laboratory and field conditions and compared the accumulated fine sediment to that contained in adjacent gravels as indicated by McNeil core samples. Our results suggest the boxes can be used as an alternative to core sampling for monitoring intergravel fine sediment levels. Advantages include ease of transport to remote field sites, small sample volumes, and reduced analysis time. Problems encountered were displacement of boxes by flood and ice flows and inundation by large sediment spills.

Development of Off-Channel Habitats for Use by Juvenile Chinook Salmon

Abstract Fisheries habitat improvement frequently requires the exploitation of existing or artificial features of stream channels and associated floodplains. Along the Yankee Fork of the Salmon River, four series of off channel mining dredge ponds were connected to the river by excavating channels; surface-water control structures were installed to regulate flow through each series of ponds. The project was created to increase rearing habitat for juvenile chinook salmon Oncorhynchus tshawytscha. Highest fish densities (5.2/m2) in the newly constructed pond series were in connecting channel habitats. These densities were higher than those reported in other streams and may have been related to the hatchery origin of the stocked fish. Densities observed in the ponds were similar to those reported in natural habitats. Addition of habitats through incorporation of dredge ponds increases management options for rebuilding chinook salmon populations in the stream.

In Situ Freezing as a Cause of Mortality in Brown Trout Eggs

Abstract In November 1975, 60 Vibert boxes, each containing 100 green eggs of brown trout (Salmo trutta), were placed in artificial redds in the Laramie River in southeastern Wyoming. Water depths and, velocities were measured, and a representative substrate sample was collected at each site. Because of extensive ice cover in March 1976, only 20 of the 60 boxes of eggs were recovered. Survival of eggs in these boxes was low (average, less than 1%), and only 10 of the 20 boxes contained live eggs (survival range, 0.5 to 3.4%; average, 1.95%). Three boxes were completely frozen, even though they were buried 15 cm in the substrate and covered with 12 to 20 cm of flowing water. Eleven of the 20 redds, including two of the frozen sites, fell within established spawning criteria for brown trout (water depth, 9 cm or more; water velocity, 15-46 cm/s). No correlation was demonstrated between water depth and survival (r = 0.51) or between water velocity and survival (r = -0.21). Extremely low water temperature and...

Sediment Deposition within Fry Emergence Traps: A Confounding Factor in Estimating Survival to Emergence

Abstract We provide evidence that the effects of sediment infiltration and deposition within fry emergence traps can lead to a potential negative bias when estimating survival to emergence (STE) of salmonid fry. Fry emergence traps were placed over 12 redds of brown trout Salmo trutta located in sections of three streams in the upper Clark Fork River system in Montana. The redds were capped in March 1989 and monitored through June 1989. During this period, sediment deposition became noticeable inside 8 of the 12 traps. During the final removal of the traps, substrate core samples were collected from a location inside and outside of each emergence trap. Substrate size gradation analysis indicated that concentrations of fine sediments (≤0.84 mm in diameter) were significantly higher in samples collected inside the traps than outside. These results suggested that the local sediment transport capacity was reduced within the emergence traps, resulting in increased deposition of fines. An understanding of the h...

Considerations in Assessing Flushing Flow Needs in Regulated Stream Systems

It has long been recognized that the regulation of stream flows can both positively and negatively affect existing fishery habitat and fish populations. This became most apparent in the western states where natural precipitation and runoff patterns had already produced well-defined periods of low streamflow.