Laserfiche WebLink
<br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br /> <br />1'11'\",('1:)01 <br />t) _' tJ, J. <br /> <br />SECTIONTHREE <br /> <br />Whooping Crane <br /> <br />2. Unvegetated <br /> <br />3. Fine substrate, usually sand <br /> <br />4. Good horizontal visibility unobstructed from riverbank to riverbank and at least a few <br />hundred yards upstream and downstream (or to a bend in the river) at all sites <br /> <br />5. Good overhead visibility, absence of tall trees, tall and dense shrubbage, or high banks near <br />the roost <br /> <br />6. ShaI]ow water except in the main channel (aU sites evaluated were less than 12 inches deep <br />and six of nine sites were 2 to 6 inches deep); water in the main channel may be considerably <br />deeper <br /> <br />7. Slow flow, approximately 1 to 4 miles per hour (1.5 - 5.9 feet per second), although water in <br />the main channel may be flowing faster <br /> <br />8. Proximity (usually 1 mile) to suitable feeding sites <br /> <br />9. The presence of unvegetated sandbar with very low elevation above water and near the <br />middle of the river <br /> <br />] O. A distance of at least 0.25-mile from roads, houses, and railroad tracks <br /> <br />Sites used on the Platte River over the past two decades conform with these criteria (Table 3-3). <br />Usually, Platte River stopover sites are at least 0.25-mile from bridges, roads, and occupied <br />dwellings. Upstream and downstream visibility at Platte River roost sites averaged 1.2 miles <br />(Faanes ] 992). <br /> <br />Analysis of 57 confmned use sites on the Platte River indicates a strong whooping crane <br />selection of the widest available channels (i.e., channel width is the distance across the active <br />channel bed, where horizontal view is unobstructed by perennial, woody vegetation or channel <br />banks) (FWS 1997). Use of channels wider than 900 feet is disproportionately high in relation to <br />their low availability. Channels less than about 500 to 700 feet wide appear to be selected <br />against, and channels less than 500 feet are seldom used. The sites used for roosting were <br />typically filled with water or nearly so. The total wetted width was generally 90 to ] 00 percent <br />of channel width (median 94 percent, range 55-100 percent). The water depths vary across the <br />channel at each site, providing shallowly submerged sandbars and deeper channels around the <br />sandbars (Faanes et al. 1992). The deepest channel at the sites has ranged from 1.5 to 3.5 feet <br />(FWS 1997). <br /> <br />A swnmary of the availability of whooping crane roosting habitat by bridge segment is provided <br />in Table 3-4. Data in this table are based only on river width and absence of nearby <br />developments. Maps showing the distribution of the habitat classes are provided in Appendix A. <br /> <br />Using habitat characteristics of known whooping crane use sites, the Biology Work Group of the <br />Platte River Management Joint Study (Joint Study) modeled roost habitat quality on the Platte as <br />a function of river discharge. This application was undertaken by the FWS, BOR, and many <br />participating federal, state, and private agencies during 1984-1993 as part of the Joint Study of <br />endangered species (BOR ]987; FWS 1987b). Specialized adaptations of the Instream Flow <br />Incremental Methodology (IFIM) (Bovee 1982) were used. <br /> <br />."..., ....ant CIJfIe <br />Fe/IIIfiII Ie. .tA.4S <br /> <br />68F0097286OO't1.doc 6J2I1999(9:52 AMYURSG'NCFS/2 3-7 <br />