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z <br />The Cottonwood Ranch sampling site is on NPPD's Cottonwood Ranch Property 8 km upstream <br />of the U. S. Highway 183 River Bridge. When study sites were picked the management plans for <br />this property were being developed that would include construction of least tern nesting habitat <br />as required under the FERC License for Project 1835, Article 407. Since fish monitoring begin <br />prior to construction of tern habitat the study area was established on the western edge of the <br />property in the area sampled in the past by the Districts (Chadwick 1993). <br />The Alda sample site was added in 2003. The Alda site is 2.4 km east of the Alda Bridge and <br />south of the Platte River Whooping Crane Trust Administrative Building. This site has been <br />sampled in the past Chadwick (1993) and thus has some historical information. This section of <br />the river went dry annually in late summer 2002 through 2006, but not in 2007 <br />Methods <br />Each study area is a 200 m reach of river (600 foot reach was sampled in 1999, 2003 and 2005) <br />within the banks of the main river channel. The 200 m reach of river was established by <br />measuring along each bank with a laser range finder. All surface water habitats within this reach <br />were sampled. Within each 200 m reach, habitat was classified into open channel, open channel <br />and side channel bank, open channel snag, backwater, isolated backwater, slough, pond and side <br />channel (WEST 2007). Open channel was defined as the flowing portion of the active channel <br />area greater than 23 m. Bank habitat is the banks adjacent to open channels. Snags are defined <br />as woody debris in the open channel areas. Backwaters and sloughs are areas of minimal <br />velocity that are connected to open channel habitats at either their upper or lower end but not at <br />both. Isolated backwaters and ponds are still water areas not connected to the open channel at <br />the time of sampling. Side channels were channels less than 23 m in width. <br />From 1999 - 2005 open channel area was determined by taking three channel width <br />measurements equally spaced in the 600 foot reach. In 2007 channel width was measured at 6 <br />equally spaced transects. Each one of these measurements consisted of walking a straight line <br />perpendicular to the flows and measuring the width of water on each sub-channel with a laser <br />range finder. A mean water width was calculated based on these measurements and multiplied <br />by the length to get total open channel area. Area of bank, snag, and backwaters was estimated <br />by measuring the length and width of rectangle that most closely defines the habitat. Area of <br />side channel was calculated by measuring width at 6 equally spaced transects using a laser range <br />finder. <br />Fish Abundance Sampling <br />Fish abundance was estimated by utilizing methods developed by Chadwicks and Associates <br />(1992). All fish abundance sampling was done in the 200 m reach described above. Open water <br />habitats were sampled using 1/8-inch mesh seines to enclose an area 25 ft(7.5 m) by 50 ft(15 <br />m) (WEST 2007). All fish were then seined out of the enclosed area identified to species and <br />counted. In 1999 through 2005 a total of 10 randomly placed replicates of this seining procedure <br />were completed in open water habitats at each study area, except at the Lexington and Overton <br />sites where insufficient area was available for 10 seines in these two areas 5 seines were <br />completed. In 2007 a seine sample was taking at on each of the 6 width transects, 2 sienes were <br />taken in the southern 1/3 of the channel, 2 in the middle 1/3 and 2 in the northern 1/3 of the