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<br />Creek down~troam to ~ev~da Avon~~. ho~ovor. leV8ee in the vicinity
<br />of the ~unic1pa':' Po,"p.r Pla"t are O"on.:ructBCl. ~t leoet part1olly,
<br />.'~itn Hy_a.h 'J'"lich ~orlllOt r".ist CO".;',,", fl'u", fluud",~l~,'~. Th~,'~.,
<br />fore, although nOt ~hown on the flooced o.ea pl~tes. a po.tion of
<br />the ~ow"r plont area co~ld be flooded by the IRF if tho l"voo~ foil,
<br />as it 16 with the Standard Project Flood (SPf). Tho SPf is predict Ad
<br />to flood eo~owh~t beyond the area. flooded in 1935 6nd to a oept~ of
<br />2 to 4 feet groater. The residential are~ most v~lner~blo to flooding
<br />in Colorado Springs liB$ generally ~long the north b3nk of Fountain
<br />Creek b9tween Neveda Avenue, Las Vegss Stroot ~nd Shooks Run. ~obile
<br />home perkS ~long Fountain Creek will be eubjoct to oovoro flooding in
<br />caee of floods even lese than the IOO_year or IRF. Included will be
<br />the L&L Treiler Ranch on the north benk Ju~t downstream from Nsvado
<br />Avenue and tha Garden Volley ~ob11e (Homs) Park on th~ suuth b~nk
<br />between Janitell Road and South Circle Drive. Between U.S. Kigh~ay
<br />85-87 (River mile 45.83) and tho Fort CarBon Ro~d bridges, along the
<br />~outh or ~eet bank, an "xle"eive development of mobilo and pormar,ent
<br />type homes will be flooded ~xtens1vely by Intermed1atr Regional and
<br />5tandsrd Project Floods. An existing levee eyet~m in this area will
<br />provida little proteotion againet large floods: e.g., the IRf or SPF
<br />due to exten.ive backwater condi Hons. These leve,,~, as well a6
<br />dsvelopments, encro~ch upon the flood plains of fountain Creek,
<br />restricting normal passage of floodwatere, therefore increasing flood
<br />hazards in this area.
<br />In the Southmoor Addition of fountain on the ",orth bank
<br />ofFountainCreek,neartheproposedStateHighwayl6bridge,'eoveral
<br />blockS of reeidential housing are subject to flooding.
<br />flooding at Fountain is generally limited to west bank
<br />floods of 5PF magnitud", involving" faw blocks north of, and an
<br />extensive area eouth of U.S. Highway 85~87 (River Mile 35.07).
<br />fovntain Creek below th" mouth of Jimmy Camp Creek
<br />has experienced very little encroachmont, except from the Old Pusblo
<br />Road and the D&RCW Railrood bridges. These bridges ~oupled with
<br />
<br />t~c ext~~siv~ rellr~ed ~~d div~~t f'loodflo'-"c ~nwnstr~"", for sev"r,,:
<br />ti"10u~OnG fBst b~fcre th~y 0.066 the ,."ilro,,(1 b"d ~nd return tlJ t"e
<br />ruufl'.,in C:ee~ LOOd ~laln.
<br />
<br />VelodUes. Rete" of "lise, and Dur~lion
<br />The O~~ur~~nc~ of the Inter~edi~t~ Rp~ion~l Or Standard
<br />Proj~ct Flood ,"ould result in the flOOd c.hereChrisHcs ",how" in
<br />Tabla S. This data rsflects the averaged maxl~um conditions with
<br />heighte of ris~, r~tes of rise, and durotions of flooding ''''a~ured
<br />ebovB bankfull .tage.
<br />flood flow v~lo~itie. depend upon the generel waterway
<br />configuration, and ths size, shape, snd elope of strs~mbed and Over-
<br />b~nk flow arB~5. Velocities may reng& from the m~ximum8 app~oring
<br />in Table 5 to le8e then 50 perc~nt of theae values.
<br />
<br />Obotructions
<br />Bruah and debrie was~ing downstrea~ during floods often
<br />ooll~ct a90inst bridg~e or within eny rastricteCl flow er~a, reducing
<br />the w~terway ope"ings ~nd otherwise impeding floodflow. Thi~ creote~
<br />a demming effect ~nd, depending upon the degree of clogging, CauSee
<br />gre~tsr backwater dspths with inore~sed overbank floocing. Water
<br />pressure, building against embankments and bridgoo, can then result
<br />in ~eriou~ sro~ion, stress dam~ge, or tot~l deetruction of the
<br />structure involved. A "Hydr~ulic Jump" c~n occur at many roadway
<br />approaches to bridges, ~ithin the fount~in Creek etudy aree__and
<br />mOts notica~bly throughout the Jimmy Cemp Creek study ,rea. The ju~
<br />oc~ura when high velocity flows "'e~t an obetrudion, forcing flow to e
<br />higher al~vation then normally predicted. A pronounced increase in
<br />flo~ velooities uou~lly occurs do~strea~ from ~n obatruction, thus
<br />e~tending the flood's da~~ge potenti,l. Obstructive new development
<br />~nd future land filling in or near tha stre~~'a floodway can be e
<br />mojor factor in m~ltiplying the advet.e effects dsscribad.
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