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. . . .. .. . . . Federally listed and proposed listed endangered andthreatened species. and their designated critical habitat; will consider comments furnished by local public officials and the general public and use the information. as appropriate, to supplement information and recommendations provided by the above Federal and State fish and wildlife resources agencies; and will detetminl:!' the need. for any mitigation by assessing ecological resources gains and losses attributed to alternative plans~ A summariiedstatementof compliance with enviromnentallaws and executive orderS will be prepared. . . . . '. . . . '. . . . (Note - the. water supplyplarining analysis, will analyze any far downstr~meffect.on threatened . and endangered species Platte River habitat in Nebraska) . Habitat-based evaluation methodologies will be used to the extent poSsible to describe and evaluate ecological resources and benefits!imp~cts associated with alternative plans. The Corps will use the ecosystem assessment method~IQgy developed in Step 2. The method win. involve . outputs in acres of stream habitat andri parian habitat . improved and/or gained~The metho<r\vill also involve outputs in quality as discussed in Step 2. . .. Regarding the simplest. least costly approach that would give an approximation of ecosystem. units. the analvsis milZht work as follows for wintertime target flows - it would be essentiallv a top width analysis. We know thatthe added flows within the.targetedrange will make pools and. runs deeper and slower,' which is' the most important winter habitat of most fish species found in . the South Platte, And we know that the added flows will provide soine added top width, which will provide open water that is shallow that is preferred by wintering bird populations. Thus, for each alternative with winter time flow increase, we can. claim the entireb3seline top width acreage for winter fish habitat benefit because the alternative will have made all the pools and runs deeper; and we can claim the added top width acrea~e as added wlnterin~ bird habitat. because the alternative will have add~d that habitat, and the existing shallow open water habitat will not have been made so much deeper as to be unusable. And we would figure out something. similar for other timesofthe year once the workgroup of fish andwildlife stakeholders develops those in-stream flow targets. . . .. . . Regarding the more detailed and accurate approach. depth and velocity IZrids would be developed and mapped for each alternative. and then related to not on Iy the tar~et flows. but also ecosystem indicator species based upon preferred depth and velocity requirements forthose species for the time of year involved~ This approach would enable a more detailed a.creage calculation for a mix ofrepresentativelindicator speCie~ and their specificneeds,and would enable a visualization of wherethe outputs would occur. . . For either method. the stream bank and vegetation conditions would be considered in making determinations of where andhow much.riparian habitat would be improved by the added flows and their timing. The 1996-1998 Denver Audubon Society vegetation mapping would be utilized:.Polygons of riparian habitat that would be considered benefited (ie. vegetated shoreline habitat made wetted longer) by the added flows would be detennined. It may be that some eco- hyrdo relationships can be developed for.some shoreline habitats because we know that added flows wHlimprove biotic conditions and food chains in and adjacent to the river. And it may be that the detailed. approach would enable a beth~rdevelopment oft1te rehitiOllships. As discussed in' Step 2, either approach will also involve outputs in qmllity. Quality indexes ~i11 relate to the need of indicator soecies.. stream bank conditions. and stream flow conditions. For example, the closer the upper numbers of the range of target flows is achieved by an alternative the better the biotic conditions will be, and the index will recognize that. Banklines that are steep, armored, and with weedy vegetation will be indexed differentthanbanklines that are not steep 10