|
<br />Colorado Flood Hazard Mitigation Plan - 1999
<br />
<br />tras~ annual precipitation on
<br />the plains east 01 Denver,
<br />Colorado, and In the South
<br />Park area In the southwest
<br />part 01 the basin, ranges lrom
<br />5 to 7 inches. Most 01 the pre-
<br />cipitation on the plains occurs
<br />as rain, which lalls between
<br />April and September.
<br />
<br />Rangeland Is present across
<br />all areas 01 the basin except
<br />over the high mountain lor-
<br />ests, AgricuKural land is re-
<br />stricted mosijy to the plains,
<br />Urban or built-up land Is pre-
<br />sent primarily along the Front
<br />Range urban corridor In Colo-
<br />rado,
<br />
<br />, ' -
<br />l_l~9~_F100d Event Great~~t ,I D1p,act Ar_e~s Fig. 2.5
<br />
<br />EI Paso and
<br />Pueblo Counties
<br />. The flooding that occurred
<br />along Fountain Creek and
<br />the Arkans.. Rlver was
<br />slgnlllcant and will be con-
<br />sidered the worst flooding
<br />event since 1965,
<br />
<br />La Junta
<br />
<br />Otero County
<br />
<br />. Weather reports Indicated
<br />that eight Inches 01 rain
<br />occurred over a three-day
<br />period,
<br />
<br />. The Arkans.. Rlver broke
<br />the dl kes near North La
<br />Junta, flooding 200 resi-
<br />dences and businesses,
<br />
<br />The Stonn Affected these Additional Areas
<br />Bent, Crowley, Custer, Elbert. Fremont, Kiowa, Las Animas,
<br />Otero, snd Weld counties.
<br />
<br />Phillips County and parts 01
<br />Lincoln and Elbert Counties
<br />have drainage tributaries to
<br />the Republican River. The
<br />Republican River is, In turn, a
<br />tributary to the Kansas River
<br />in Kansas, The Republican
<br />River Basin in Colorado consists primarily 01 rangeland
<br />with some farming and ranching communities scat-
<br />tered throughout the basin,
<br />
<br />The Arkansas River Basin is very similar to the South
<br />Platte River Basin in topography, geology, and hydrol-
<br />ogy, Annual mean temperatures are slightly higher
<br />than the Platte River Basin, Annual rainfall amounts
<br />average between 7 and 15 inches, except In the moun-
<br />tainous areas 01 the Basin. Land use is similar as well
<br />and consists mainly of agricuKure,
<br />
<br />Crowley, Kiowa, Otero, and Prowers counties are
<br />drainage tributaries to the Arkansas River. In add~ion,
<br />portions 01 Elbert, Lincoln, and Baca counties are
<br />within the Arkansas River Basin,
<br />
<br />A very small part 01 the incident area lies within the
<br />Cimmaron River Basin. The southem portion 01 Baca
<br />County has drainage tributaries to the Cimmaron
<br />River. The Cimmaron River flows from Colorado into
<br />Kansas and then into Oklahoma where ~ ultimately
<br />joins the Arkansas River in Tulsa, The Cimmaron River
<br />Basin is similar in topography and climate to the Ar-
<br />kansas River Basin,
<br />
<br />1999 " Flood Evenl Description - The three-day rair>-
<br />lall event occurred on April 29-May 1, 1999, Heavy
<br />rain and saturated soil caused flooding in two major
<br />areas along the Front Range: Northeastern Colorado
<br />along the South Platte River and some 01 its tributar-
<br />
<br />ies; and Southeastern Colorado along the Arkansas
<br />River and some its tributaries,
<br />
<br />Rainfall totals 01 up to 13 inches were recorded in the
<br />Cheyenne Mountain region 01 Colorado Springs, The
<br />La Junta region recorded approximately 6 inches over
<br />the same three-day period The Arkansas River broke
<br />the dikes near North La Junta, flooding approximately
<br />200 residence and businesses, The stormwater runoll
<br />Irom the three-day general rain resulted in large flood
<br />Inundation and erosion in the Arkansas River and
<br />Fountain Creek watersheds,
<br />
<br />These rainlalltotals are large, but not extreme in c0m-
<br />parison to the largest storms experienced in Colorado,
<br />What made this storm so interesting (and the flood
<br />flows SO large) was the fact that rainfall was SO wide-
<br />spread that most 01 the affected besins were receiving
<br />heavy rainfall basinwide, This is not the "norm" lor
<br />Colorado, Also, rain on snow is generally not a great
<br />problem In Colorado, but sizeable areas 01 the Front
<br />Range loothills did receive heavy rain on top 01 several
<br />inches 01 saturated snowpack. The meK rate 01 this
<br />snowpack was low, but additional water was added to
<br />the runoll.
<br />
<br />The flooding that occurred along Fountain Creek and
<br />the Arkansas River was significant and will likely be
<br />considered the worst flooding event since 1965, How-
<br />ever, the storm affected Bent, Crowley, Custer, Elbert,
<br />EI Paso, Fremont, Kiowa, Larimer, Las Animas, Otero,
<br />
<br />Chapter 2 - 6
<br />
<br />l1UXl5:30 PM
<br />
<br />I
<br />
<br />I
<br />
<br />I
<br />I
<br />
<br />I
<br />I
<br />I
<br />
<br />I
<br />I
<br />I
<br />I
<br />I
<br />
<br />I
<br />
<br />I
<br />I
<br />I
<br />I
<br />I
<br />I
<br />
|