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<br />GLOSSARY <br /> <br />Backwater effect. the rise in surface elevation of flowing water upstream <br />from and as a result of an obstruction to flow. <br /> <br />Channel. A natural or artificial watercourse of perceptible extent with <br />definite bed and banks to confine and conduct continuously or periodically <br />flowing water. <br /> <br />Cloudburst. A sudden extremely heavy downpour of rain that is small in <br />areal extent; of short duration; and may be accompanied by lightning, <br />thunder, and strong gusts of wind. <br /> <br />Conveyance capacity. <br /> <br />a. Channel conveyance capacity is the rste of discharge, in cubic <br />feet per second, which can flow in a water course with the water <br />surface not greater than the height of the channel banks. <br /> <br />b. Floodway conveyance capacity is the rate of discharge in the <br />overflow purtiou uC the floodway which c"n pass through a <br />specified area at depths and velocities governed by the hydraulic <br />dimensions of the floodway. <br /> <br />Designated flood plain. The area designated as a flood plain by official <br />action of the board of county commissioners or city council with the prior <br />cOncurrence of the Colorado Water Conservation Board. <br /> <br />Flood. An overflow on lsnds not normally covered by water snd that are <br />used Or usable by ..an. Floods have two easential characteristics--the <br />inundation of land is temporary; and the land is adjacent to and inundated <br />by overflow from II river or stream or an ocean, lake. or other body of <br />~t"nding water. <br /> <br />Normslly a flood is considered as any temporary rise in streamflow or <br />stsge, but not the ponding of surface water, that results in significant <br />adverse effects in the vicinity. Adverse effects may include damages from <br />overflow of land areas, teaporary backwater effects in aewers and local <br />dr..inage channels, creation of unsanitary conditions or other unfavorable <br />situations by depositiOn of m.~tcrials in stream channels during flood <br />recessiona, use of ground water coincident with increased streamflow, and <br />other problems. <br /> <br />Flood, lOa-year. A type of flood, including the water-surface elevatioo <br />and territorial occupation thereof, which tan be expected to occur at any <br />time in a given srea baaed upon recorded historical precipitation and other <br />valid data, but with an average statistical one percent chance of being <br />equaled or exceeded during anyone year. <br /> <br />flood crest. The maximum stnge or elevation reached by tne Waters of a <br />flood at a given location. <br /> <br />Flood frequency (see Probability). <br />specific discharges or water stages <br /> <br />recurrence interval of <br />flooding. <br />R€\OURC€ CON\UlT~NT\ INC <br /> <br />The average <br />which cause <br /> <br />" <br /> <br />flood peak, The rnaxi~um inatantaneous discharge of a flood at a given <br />location. It usually occurs "t or near the time of the flood crest. <br /> <br />Flood frin~e. That portiOn of the flood plain between the floodway <br />district boundary and the upper limits of the base flood. The flood fringe <br />is the portion of s drainway channel or watercourse outaide the floodway <br />portion. <br /> <br />Flood profile. A graph showing the relationShip of water-surface elevation <br />to lco"tion, the latter generally expressed as distance above mouth for a <br />stream of water flowing in an open channel. It is generally drawn to ahow <br />surface elevation for the crest of a specific flood, but may be prepared <br />for conditions at a given time or stage. <br /> <br />Flood staKe. The atage or elevation at which overflow of the natural banks <br />of a stream Or body of water begins in the reach Or area in which the <br />elevation ia measured. <br /> <br />, <br />i <br />I <br />" <br /> <br />Floodway. The channel of a river or other watercourse in the adjacent land <br />areas that must be reserved in order to diacharge the base flood without <br />cumulatively increasing the water surface more than 0.5 feet. <br /> <br />" <br />, <br />, <br /> <br />Left bank. <br />the observer <br /> <br />The bank on the left <br />looks upstream. <br /> <br />side of a rivet, stream or watercourse as <br /> <br />Probability. The annual chance of ocCurrence of specific hydrologic ents, <br />such as rainfall over a speCified area or peak discharge at " specified <br />location expresaed in percent, e.g., 5 percent represents 1 chance in 20 of <br />the event occurring in any year or an average recurrence of once in 20 <br />years. <br /> <br />Reference point. A numbered point identifying n specific location for <br />correlating the datn shown in various forma throughout the report. <br /> <br />RiRht bank. The bank on the right side of a river, stream or watercourse, <br />looking upstream. <br /> <br />Runoff. The quantity of rainfall which flows over the surface to enter the <br />stream aa discharge volume. The differeoce in quantity between rainfall <br />and runoff represents loases to infiltration and interception. <br /> <br />Sheet flow. <br />to 2 f"etin <br /> <br />Broad, <br />depth. <br /> <br />shallow overland flood flows varying from a few inches <br /> <br />Stream. Any natural channel or depression through whiCh water flows either <br />continuously, intermittently or periodically, including sny artificial <br />modification of the natural channel or depressiQn. <br /> <br />'.Iatershc<l. Ihe drainage area situ..otio.. above a spec1fi"d point On a <it,e,,", <br />including the area drained by tributary streams Which enter th~ main stream <br />above this point. <br /> <br />" <br /> <br />R€\OURC€ CON\UlT~NT\ INC <br />