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<br />. <br /> <br />. <br /> <br />Ta b1e 7 <br />Timing of Mountain Flood Runoff(l) <br />Cache La Poudre River Basin <br /> <br />Stream and Location <br />North Fork Cache la Poudre River <br /> <br />Rainf all to <br />Flood Peak(2) <br /> <br />Time Interval <br />Rainfall to <br />S ignif icant <br />Flooding(3) <br /> <br />(Hours) <br />First Rise to <br />Significant <br />Flooding(4) <br /> <br />Above Halligan Reservoir <br />Below Halligan Reservoir <br />Below Lone Pine Creek <br />Mouth <br /> <br />3 3/4 <br />6 1/4 <br />6 1/4 <br />7 3/4 <br /> <br />3/4 <br />1 1/4 <br />2 <br />1 1/2 <br /> <br />2 1/4 <br />4 <br />3 <br />4 1/4 <br /> <br />Lone Pine Creek <br /> <br />Mouth <br /> <br />3 3/4 <br /> <br />3/4 <br /> <br />2 1/4 <br /> <br />Cache la Poudre River <br /> <br />Poudre Park <br />Canyon Mouth <br />Near Laporte <br />Fort Collins <br />Larimer-Weld County Line <br /> <br />3 1/4 <br />3 3/4 <br />5 <br />7 3/4 <br />15 1/2 <br /> <br />1 <br />4 <br /> <br />1 1/2 <br />2 <br />3 <br />4 1/4 <br />11 3/4 <br /> <br />3/4 <br />3/4 <br />3/4 <br /> <br />(1) The flDOd in the plains is assumed to originate from the main stem <br />in the mountains, which has more rapid runoff than the North Fork <br />watershed. No rainfall was assumed over the plains. The 100-year <br />flood was used in the timing analysis, but other floods wDuld not <br />differ materially. <br /> <br />(2) Time from 15 minutes after start of heavy rainfall to peak discharge. <br /> <br />(3) Time from 15 minutes after start of heavy rainfall to threshold Df <br />significant flooding (defined as 5,000 c.f.s. on major streams and <br />2,500 c.f.s. on major tributaries). <br /> <br />( 4) <br /> <br />Time from noticeable rise in streamflow (defined as 1000 c.f.s. on <br />major streams and 500 c.f.s. on major tributaries) at the designated <br />location to threshold of significant floDding. <br /> <br />29 <br />