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Gl05S^Rr OF TERMS , Flood Profile ^ gr~ph showIng the relationship of water surface ele- vationto location, the lattllr generally exprllssed as distance abovelOCluth for a stream of water flowing In an open channel. It is generally drawn to show surface eievatlon for the crest of a specIfic tlood. but may be prepared tor conditions at ~ given time or stage. high water marks shown and Isa "best fit" profile. Elevation- dischargecurvessllowlngtlleIO-year, 50-year, IOO-year,and50Q- year floods are also presented. These curves lire loceted at the surveyed cross sectlon~ which were not used in computing water surheeprofiles. Thedatapresentedbythcsecurvesisbesed upon relationships developed from physical characteristIcs ot the respective cross sections end 1973 flood data. A detailed study may Show significantly different results. The flooded area plates show photographs of the flood of May 1973. The locations of observed high water marks from tllat fl<x>d are also shown. Thes'-'platesalsoshowthe limits of the IOO-year and 500-year floods lit eacll eross section as determined from the water surface prof lies or elevat ion-d ischarge curves. I n c~ses where surveyed cross section information waS extended by using U. 5. Geological Survey 7.5 Minute Quadrangle Mapping, an asteris~ (')denotesthatthelimltso/theIOO-yearand500-yearfloods are approximate. The location of these flood limits at points between the cross sections where water surfnce profiles are pre- sontedcnnb!!detnrminodbysp.lectlngfhepr"perw<iltersurfilceele- vatlon from the water sur/ace profiles and establiSh that point on the floodplain by survey. Similarly,/Ioodcheractcristicsat points between cross sections where woter surface profiles are not presented can b,-, estimated by noting thp. elevation differences beh.e"" the d",sire~ fl=d and the 1973 flood on the clcvatlon- discharge curves and applying the5e relntlonshlps t~ the flond characterlstics as viewed on the 1973 aerial photosattbedesirad location. U. S. Geologicol 5urvey quadrangle maps provide valuable information tor transferring relationships. FlOOd . An overflow on lands not normally covered by water and that are used or usable by man. Floods have two essentla! ch~r- acterlstles: The inundation of land Is temporary; and the land is adjacent to and Inundated by overflow from a river or stream or an ocean, fake, or other body of standing water. Normally a flood is considered as any temporary rise In stream flow or stage, but not the pondlng 0/ surface water, that results In significant adverSe effects In tile vIcinity. ^dverse effects may Include damages from overflow of land arcas, temporary backwater effects In sewers and local drainage Channels, creatIon 0/ unsanitary conditions or other unfavorable situationS by deposi- tIon of materials In stream channels during flood recessions, rise of ground water coincident with Increased stream flow, and otller problems. Flood Crest The maxImum stage or elevation reaches by the waters of a flood <It Flood Plain The rel<ltlvely flat are<l or low lands adjoinIng the channel ora river, stre<lm, watercourse or ocean, Ii>ke or other body of standIng water, whiCh has been or may be covered by floodwater. " ,8