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The area delineated on the Flooded Area plates as the 100-yesr floodplain meets the requirements of H.B. 1041 as an area of state interest. Also upon official approval of this report by the Colorsdo Water Conservation Board the area outlined by the 100-year flood boundary will be designated a floodplain area and fiay be regulated accordingly by the local officials. Flood Elevations Flood crest elevations for the 10-, 50-, 100-, and SOD-year floods may be found in four separate locations in this repo>:'t. The Flood F>:'equency-Elevations and Discha>:'ge Data table, Table 3, liat these elevationa at selected refe>:,ence points. The Flooded A>:'ea Plates 3 through 11 give the plan view of the flooded area. The Flood Profile plates, Plates 12 through 22, show the streambed elevation and the high water elevstions for all four frequency floods. Also the Crosa Section plates, Plates 23 through 26, show a graphical representation of the high water elevations at typical valley cross sections throughout the study reach. GLOSSARY Backwater Effect. The rise in surface elevation of flowing water upstream from and as a result of an obstruction to flow. Channel. A extent with continuously natural or artificial watercourse of definite bed and banks to confine or periodically flowing water. perceptible and conduct The Flood Profiles may be used in areas where controversy arises ove>:' the 100-year flood bounda>:,y on the Flooded Area plates. S1.nce the Flood Profile plates give the elevations and distance or stationing f>:,om a known point, the high water elevations can be surveyed on the gound to 8.11ev1.ate any d1Bcrepancies on the base map. Benchma>:'ks used in the compilation of data for this study are included 1n the Technical Addendum. , I i I , Cloudburst. A sudden and extremely heavy downpour is small in areal extent; of short duration; accompanied by lightning, thunder, and st>:'ong gusts Conveyance Capacity. a. Channel conveyance capacity is the rat" of discharge, in cubic r"et per second, which can flow in a wate>:, COurse with the water surface not greater than the height of the channel banks. of ra1.n that and may he of wind. b. Floodway conveyance capacity 1.s the rate of discharee 1.n the overflow portion of the floodway which can pass through a specified area at depths and veloc1.ties governed by the hydraulic dimensions of the floodway. Designated Floodplain. The area designated as a floodplain by otfic~al act~on ot the board of county commissioners or city council with the prior concurrence of the Colorado Water Conservat1.on Board. Flood. An overflow on land" ll<',t nO>:'mally covl'>:'ed by ""ater and that are used or usable by man. Floods have two essential characteristics; the inundation of hnd is tempo["ary; and the land is adj8eent to and inundated by overflow from a dver or stream Or an ocoean, lake or other body of standing water. Normally a flood is considered as any temporary rise In streamflow or stage, but not the ponding of surface water, that results in significant adverse effects in the vicinity. Adverse "ffects may include damages from overflow of land areas, temporary backwater effects in sewers and local dr8.1.n.sge channels, creation of uns.snitary conditions or other unfavorabl.. situat1.ons by deposition of materials in stream channels during flood recessions, use of ground water coincident with increased streamflow, and other problems. -19- Flood, lOO-Year. A type of flood, including the wster Hurfac.. elevation and territori81 occupation thereof, whiCh Clln be expected to occur at any time in a given area ba~ed upon recorded -20-