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GLOSSARY OF TERMS ! Doc' Surface of roadway or to~ of railr~d ties at c~ntor nf bridge. , r r I . i ~: ~ t' l "000 An o~erf low on lands not norma I'y covered by ",ater and that are used or uSllble by man. Floodshavetwoessantlalchari3ctcr- lstlcs: The Inundation of land Is temporary; and the land is adJacent to and inundated by overf low from a rl~er or stream or an ocean, IlIke or other body of standing water. Normally a flood !s considered as any temporary rise in stream flow or stage, but not the pendIng of surface watar. that results in significant adverse effects in the vicinity. Adverse effects may include damages from overflow of land areas, temporary bllckwater effects in sewers and local dralnago channels, creation of unsanItary conditions or other unfavorable situations by derosi- tion of materials in stream channels during flood r~ossions, use of ground watarCOirlCident with IncreaSed stream flow. andotMr problarns. -1 n ,,~ r Flood Crest f . f I , I , I \'j The maximum stage or elev"tlon reached by the waters of a flood at a given location. "~, FloodPlain . The relatIvely flat aroa or low lands adjoining the CMnnel of a river. stre"mor water course or ocean. lake or ofller body of :;tand I ng w~tor, ....hich has b99n or "'IiIV bo covered by /Icod water. " Flood Profile A graph showing the relationship of ....ater surface elevlltlonto location, the lattergenera"yexpressedasdistan ee above lI".oyth for a sfreamot water tlowing In an open ehannel. It is generally drawn to Show surface elevation for the crest 01 a specific flood. but may be prepared for conditions at a gIven time or st;/lge. Flood Stage The stage or elevation at which overflow of the natural banks of a strGllm or body of water begins In the reach or area In whiCh the elevafion Is measured. Head loss The effect of obstructIons, such as narro.... bridge open- Ings or bu!ldings that limit the area through ....hlch water must flo..... raising the surface of the ....ater upstream from the obstruction. Intermed!ate Regional Flood A flood having a one percent probabi 1 ity ot occurrence In any year of an average froquency of occurrence ln the order of once In 100 years. The t lood may OCClJr In ~~i. "f':;:;'-. : ~ 1<: bas..... on statistical analysis of str~am flow records and analyses of rainfall and runoff characteristics !n the general rent~n of the ....atershed. LettBank The bank on tho left side of a rl~er. stream or ~ater course, lOOking downstream. RlghfBank The banK on the right side ot a river, stream or water course.lookingdownstroam. 20