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T\'/O runs of the flec-2. program \"Jere Inact". outf.lut are incluC:ed as Addel'ldums 1 and 2, the output for the follo\'!ing profiles: Copies of th~ computer The addendums contain T<lble~ 1 ilnd 2, consecutiv:!l Fir ' FIA Table 2. for flood ir:sura~~e ,10 '"T~!Jie 1 fo~ fIOOcl>'i~~ datil ar.d 2. and are sho\-IO in this report ~s ~;bla \ilr2 lncluded 111 Addend~!il , I" es ilod4,consecutivel,y. The 100 year flood plain is shOWn in fi flooc'/ldY fringe portions of the floo.! ~~i~ 2. The. floodway ilnd the boundaries bet\-Ieen cro%-secti^, ^ P, ilre lndlcated. Th" ". fl. "Isw"re etermin"'" using t ^. " PPln~ 0 t Ie area. The' natural 100 y fl' do...;, o~ographleill e)evatlon at each of the cross see. Cil~ 00 \i<leer. surrace boundaries bet\'Jeen the f1oocil.liIj' an~'~h~ ~;e ~hO\1n 1n Flgure 3. The shown. The water surface profiles f '00 ';lay fringes are also 500 year flood events are Sho\in in F~~u~~C~.O.f t.he la, 50, )00 and ^,',.<,_......._,<~-~ -- I I I I I I I I I I I I I I I I I I I Char'Jlel and overbank rou~hness factors ([.janning's "~nul \"ere detcn'lined frolll field inspection of the study area, A factor of 0.04 I'las used for the channel bottom. The fact.ors used for the oV€:l':'ank flo\~ areas ran!Jed fro:rr 0.05 to 0.07, dependi ng on the type of existing and proposed veget1:tion, Flo','! in the river was assumed to b~ subcritical_ Tlle Hec-2 program computes the ',Iater surf,1Ce profi le of subcritical flo'll ~tarting iltthedownstreafllendofthereachandproceedsupstrear.l, Theout- put noted that the computer assu~ad critical flow at two nonscccessivp. sections during the 50, 100 end 500 year-flood events. This indicates that the flOI'lIililY besllpercritical at those sections. However,be- cause the flow was found to be subcritical at the sections upstream and downstream and at the 10 year flow, it is believed that it is not necessary to run the profile assuming supercritical flow. Because critical depth is higher than supercritical depth,using the assurr.ed critical dept.hisconservative. ADdendum Profile No. Flood FrequlmcL Encroachment Option , , 100 No , 2 'Oil y" 2 , 10 No 2 2 50 t:o 2 3 100 110 2 , 500 No Ap~lication of Results The information regarding the fl d' h .. . ~iver determined in this analysi~o\ ~~~ b arilcterlstlcs of the Eagle 1 n the Eagle River Estates Subdi Vi;~ on t e used to hontrol. constructi on be inurldated by a flood of a magnitude nO assure t at no r~sidsmce f100C: event. The 100 fl ,0 greater than the 100 year 'in this report will b/~~~d t~O~e~~al~ area and elevations defined /10. imP'01vements shall be ~ 11 o'ded I-li~~i~e t~~n15~uct~on restrictions. t,lall1talll the nec"ssar CO" . ~ yedr floodway to flood\Jay fringe ~ill be al,~:~C\~~P~~~t~: ~of"',trtlction in th~ dcncesshall beatl t f'. us oorofalll'esl- flooC: water surface ~~~vil~il~n. oot lugher than the computed 100 year Results of Analysis Ti1.~ cncro~chrr:ent option used in Addrmdur.1 1 defines the floodwil,y ;;tnl.! the fl00d'rlay frirl:l~ port'ions of the 100 year flood plain. That option co;:;putes the encroacl1ment stations so that conveyance I ...ithin tr.e encroJchad cro~s section, at SO~2 higher el<,vation, is equal to tile conveYilnce of the natural cross section at the natural wlter level. This higher elevation is no more than one foot above the natural 100 :lear profile. The computed encroachment stations are t!l,. boundary betl1eel1 the flood',.lay and the floodway fringe, the flood\~ay being th\lt portion of the floJodplain that can maintain tilt uecessJ.ry convcy~nce if not er.croilcl1ed upon. The printoat in liddendl!i:1 1 includes all input data, Sunrnary print- mlt Table 110 for encroachment data and FIri Tab,e 1 for flooc!\-Iay d<lt.! are include,! ill /,ddendum 1 end afe shown in this r<'flort as