<br />Colorado Flood Hazard Mitigation Plan - 1999
<br />
<br />boundary to over 70 in the mountains along the Froot
<br />Range, The thunderstorm flood season in Colorado is
<br />from the middle d July through October,
<br />
<br />Big Thompson Flood (1976) - The widely publicized
<br />Big Thompson Canyon flood disaster of July 31, 1976,
<br />was a resu~ of an intense thunderstorm cell that
<br />dropped up to 10 inches d rain in a few hours CNer the
<br />basin,
<br />
<br />1993 Floods - On May 15-16, 1993, a thunderstorm-
<br />induced flood event occurred at Rifle on R~le and GeN-
<br />emment creeks. As is usually the case, the highest
<br />flows in the shortest period of time occurred when an
<br />estimated 125-year flood discharge impacted Rifle,
<br />Structures and vehides in harm's way suffered dam-
<br />ages in excess of $200,000.
<br />
<br />On June 17. 1993, a flash flood occurred on Shooks
<br />Run in Colorado Springs, Damages were confined to a
<br />mobile home park on the creek's edge with losses esti-
<br />mated at $1 Million,
<br />
<br />In July 1993, the Town d Otis and the unincorporated
<br />area d Cope in Washington County and the City of
<br />Yuma in Yuma County experienced a weekend flood
<br />event as a resu~ of three consecutive days of thunder-
<br />storms, Several homes suffered damages and road-
<br />ways were inundated with loss in excess of $650,000.
<br />In Otis, a flood control and storm dra;nage project pr<>-
<br />tecting the northern half of town worked.
<br />
<br />On August 10. 1993, flash floods occurred on several
<br />creeks in Delta County. Two roads were washed out
<br />and a flood fight was conducted with sandbags on R<>-
<br />bideaux Creek near the Department d Corrections
<br />Detention Facility.
<br />
<br />On August 26-29. 1993, general rainstorms caused
<br />flooding in Archuleta and La Plata counties. A subdivi-
<br />sion in Archuleta County was threatened and roads
<br />damaged as the Rio Blanco overflowed ~s banks south
<br />
<br />of pagosa Springs, In Durango, the Fire Department
<br />had their emergency operations plan in effect and
<br />came very close to evacuating residents d a mobile
<br />home park on the Animas River.
<br />
<br />1995 Floods - In the spring and early summer of 1995,
<br />the lower South Platte, the lower Ar1<ansas and the
<br />Roaring Fork Rivers were impacted by signifICant
<br />flooding, Most damages were experienced by agricul-
<br />tura; landowners,
<br />
<br />1997 Floods - On July 24-28. 1997. the City d Fort
<br />Collins and most d eastern Coiorado received soaking
<br />and/or drenching rains, adding to soil moisture in some
<br />locations, As the cold front arrived in the late afternoon
<br />of July 27th, strong thunderstorms developed just
<br />north and west of Fort Collins, Later that nigh~ steady
<br />rains developed along the eastern base of the foothills
<br />in Larimer County and corrtinued until about noon on
<br />July 28th, Several inches of new rain were reported
<br />just west and northwest of Fort Collins totally saturat-
<br />ing the ground, producing major flooding in Laporte,
<br />and setting the stage for the evening flood event.
<br />
<br />On the evening d July 28, 1997. intense rains began
<br />around 8:30 p.m, in the foothills west d Fort Collins,
<br />Winds from the east and southeast continued to pump
<br />moisture into the storm system throughout the eve-
<br />ning, The core of the storm was very small but re-
<br />mained nearty stationary over the headwaters of
<br />Spring Creek, the Fairbrooke Channel. Clearview
<br />Channel. the CSU Drainage Basin, and the West Vine
<br />Drainage Basin. Rainfall intensity increased and
<br />reached a maximum between 8,30 p,m. and 10:00 p,
<br />m, before ending abruptly, A subsequent analysis of
<br />rainfall conducted by CSU showed a maximum d 10,2
<br />inches of rainfall in less than five hours near the inter-
<br />section d Drake Rd, and Overland Trail.
<br />
<br />On July 29, 1997, slow-moving thunderstorms dumped
<br />large amounts of ra;nfall over the Pawnee Creek Basin
<br />
<br />Colorado Flood Facts I
<br />
<br />CountleslCltlesfT owns with Flood Prone Areas
<br />
<br />268
<br />
<br />250,000
<br />
<br />Population of 100-Year Floodplain
<br />Homes In 100-Year Floodplain
<br />
<br />85,000
<br />
<br />15,000
<br />$11 Billion
<br />$ 4.4 Billion
<br />
<br />Total Value of Property In 100-Year Floodplain
<br />
<br />CommerclalllndustrlallBuslneases In 100-year Floodplain
<br />
<br />Cumulative Flood Losses from Turn of Century to 1999
<br />
<br />Source: CWCS
<br />
<br />Figure 2.3
<br />
<br />Chapter 2 - 4
<br />
<br />1I1AXlS::30PM
<br />
<br />I
<br />
<br />I
<br />I
<br />I
<br />
<br />I
<br />I
<br />I
<br />
<br />I
<br />I
<br />
<br />I
<br />I
<br />
<br />I
<br />I
<br />
<br />I
<br />
<br />I
<br />
<br />I
<br />I
<br />I
<br />I
<br />
|