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welt of the alignment, approximately at the midpoint. This sand pit and adjacelltlands may have potential for haMrdous or toxic wa~te contamination. hahitat constitutes a signifIcant adverse impact, the channel diversion was purpo,ely aligned 10 avoid the densest riparian vegetation and the McMurry Park! NatLlral Area. In the riparian habitat, some potential exists for the occurrence ofa p1<m tproposed for listing as a federally-listed, threatened species, and a mouse listed as a State spccie~ of special concern. The plant is the Ute ladies'.tresses (Spiranthes diluvialis). It is endemic to relatively low elevation riparian meadows, and populations are known to occur in city park and greenbelt areas in the citicsof Boulder, Golden, and Wheat Ridge, Colorado. The mou~e is the Preble', meadow jumping mouse (Zaous h\l.dsonius oreblei). It is known to occur in muist wct area, in riparian zones with tall grasse,. There has bccn no re<:ordcd trapping of the spccies for 15 years. One concept for the possible mitigation of the riparian habitat loss would be the rccstablishment of riparian vegetation on an existing tra<;t of land lfl thcri parianzoneof the Cache La Poudre River. This tract would need to be one that is owned by the City and iscurrcntlydisturbcd, providing only minimal vegetation and habitat, Constmction of the channel divcrsion training levccs and earthen b<;rmsthrough the urban/agricultural fringe ecosystem would cause the conversion of approximi\lcly 21 acres (for the tOO-year plan) or 12 acres {for the30-year pli\n)of irrigated pastllrd hayland habitat that is citherCllt or grazed quite short, t021 or 12 acres (forlhe loo-ycar and 30-ycarptans re,pectively) of grassed levees that will be lIlowo:d ~riodicalJy. It would be t:~roctoo that the grassed levees and s:n.'.am ch3r.r.el weuld provide mnr~ r,,,,,I, cover, and living space for grassland species for longer periodS of time than ctlfrelllly exists. which would constitute an insigmficarH but positive impact. Of special concern to thc Colorado Division of Wildlife is any impact to the Johnny darter and common shincr, which prefer clean, clear streams with rubble and sand bottoms. shallow rimes, and an abundance of aquatic insects for food. They are intolerant of l\1rbid irrigation return flows that silt over suhstrate, Johnny darters establish ncsting territories by cleaning the underside of stones with their fins, The female then attaches her egg, to the stone so thc male can fertilize them. Spawning occurs in April or l>lay. Construction of the channel (ilversion training kv<xs and earthen berms thro\l!;h the riparian ecosystem along the Cache Ut Poudrc River would cause the lossof2 acres (fur the tQO-yearplanl or I acre (for the 30-yearplan) of rip an an habitat. Theriparii\n vegetation provides a valuahlc edge ef[c<;t betwecn the adjacent upland on one si dC.Hld watcrontheother. It also provides a valuable divcrsity ofpl1ysieal cunditions created by channel migration and vcgetatIVe succeSSIOn, Stich conditionspro\ildeconsiderJ.blc f{)lm. cos'cr. and living space for many s~:>ccies of wildlifc. Although the lo,s of such Runoff from disturl>ed areas dllring thc construction of the channel divcrsil)fl channel and trmmng leveescoLlldcauseap<Jklll;a1lysignifjcantdcli....cr)'of~c;l1ments to the Cache La POlldre River and a resulting shorHerm increase in stream turbidity. Sedimentsoftcnplu)(intergravel spaces with silt, leaving no room for fish eggs or food organisms, Sediment control measurcs w(Hlld have to be incorporated into construction plans to minimizcthisimpact. Upon c\lrnpiction of the channel diversion, !loodflowsduringa!loodeventwould OCCllr in a confmed channel instead ofanoss a \I'ide!lood plain. This would result in cunslderably less s.:dimcnt" oJebris.anrlpol1utaIltsenteringtheC'acl1e La Pmldre Klvcr during a flood event This impact would be ro(lsidered significant and hendicial. boll 6.12