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MAY-19-04 14:24 FROM-WEISS AND VAN SCOYK 970 879 6058 T-286 P.027/033 F-562 <br />7. a 12eport for City vf Siearrcboar Spri,zgs 13oacing Pczrk preparcd Uy Gary Lacy, <br />P.E. for porzak Browning & Bushong '[.,LP dated January 2004; <br />8. a letter datcd 20 January 2004 from Gary B. Tllompson, P.E. to Glenn E. <br />Porcalc, Esq., Porzalc Browning & Buslion? LLP; and <br />9. an application for surface water rights, Case Number: 03CW86. <br />10. MemorandtLm from Tom Browning, CWC'B Flood protzction Program dated <br />Apri126, 2004 submitted to Susan Schneider, Colorado Attomey General's <br />Office. <br />11. A letter rc:part from McLaushlin ?.2incon dated Apri127, 2004 submitted to Tzd <br />Kowalski, Colorado Water Conservation Board. <br />Review Comments <br />As requested Uy lV7'r. McLaubhlin, tlie focus a£ this review centered on the <br />hydraulic analysis conducted to date for the referenced project. While mtlclz of the <br />documentation provided presented insight and background of the issue of in stream water <br />rights and appropriate recreatioils use, the expertise ancl field of practice of the reviewers <br />is in che field of hydraulics, river meclianics ancl geomorphology. <br />The first area of eoncern centers on Mr. Lacy's January 2004 repon entitled <br />"Repore for City of Steamboat Springs Boating Parlc". While the rcview reveled no <br />empirical data to quantify tlie llydraulic effects of the constructed boat chutes, Enuation <br />1, located on page 11, was presented as a means to quantif.y the water deptli upstream of <br />each structure. While geizeralized forms of weir equations, for both sharp crested and <br />braad crested weirs, can be used with relativEly high confidence, application of these <br />types of equations must be made within the bounds of the goveming assumptions used to <br />simplify them. <br />Typical idealized assumptions include absence of centripetal forces on sections <br />bounding the approacli zones of acceleration, absence of increased turbulence and non- <br />uniform flow conditions, aeratian of the nappe under the impinging jet and a uniform <br />velocity distribution across the sill of the weir, Sased on observations made during tlie <br />field visit, each of these assLLrnplions appears to Ue violated in the current design. It is <br />therefore reeommended that a mueh more thorough examination of the hydra«lic contr.ol <br />provided by the boat chules Ue conducted, <br />Page 12 of Mr. Lacy's repon states: <br />"At exzreme floods Chls srrucEure will itoi significcintly affect the <br />100 year floodplain_ It is my opinion that the Park is capabde of dlverting, <br />capturing, and controlling water witltin clze river charinel at maximaim jlow <br />rcttes up to 1900 cfs. 'lhese scnictzires divert, capraire and control these <br />flows eff ciently and wllhout waste. 1'1 is aLso my opinton that these <br />straectzeres do nor ajfect the 100 year flooclplcciri. These streeCtur-es were <br />designed at grnde ro rriimic the natural shape oJthe streambed und they do <br />1)