tailspill to the downstream tip of the tailspill. Total redd lengths were calculated from the 

 sum of pit and tail lengths. We measured depths and velocities in the deepest part of the 

 redd pits (dpit); and recorded measurements directly upstream (dup & vup) and 

 downstream on the tailspill crest (dtail) and to the right (dright) and left (dleft) of the each 

 redd. To estimate water depth prior (dprior) to redd construction, water depths upstream 

 of redds were average with water depths at tailspill crests (dup + dtail) / 2. Pit excavation 

 depths (dex) in the substrate were estimated by subtracting water pit depth from water 

 depth prior to redd excavation (dpit - dprior) (Schmetterling 1999). We located all redds 

 with GPS (Garmin III plus) and noted by which third of the stream channel it was located 

 in (mid, right, left), habitat type (pool, glide, riffle) and estimated distance from nearest 

 overhead cover. 



To characterize winter water temperatures at spawning areas for the embryo 

 incubation period, we placed one thermograph (tidbit data logger) in the substrate and 

 one in the water column at each of the four spawning areas. The substrate sensor was 

 placed immediately adjacent to a redd and buried 6" in to the substrate. The second 

 sensor was placed adjacent to the same redd in the water column. Temperature data was 

 recorded from September 2004 through March 2005 at 30-minute intervals. To test the 

 relationship of water temperatures the water column and the substrate, performed a paired 

 t-test between the pooled mean monthly data for the primary winter months (December, 

 January and February) with results considered significant at the alpha <0.05 level. 



Results > 



Physiographic setting and reach morphology - . 



The broad-level physiographic features of the study area fall into the "northern 

 rockies aquatic ecoregion" (Omnerick 1988). Within the Blackfoot watershed, this 

 region includes include high, cool and humid mountains with meta-sedimentary (Belt) 

 rock types and inseptisol soils, covered by alpine meadows, subalpine and montane 



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