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Tab9e 2 <br />Values of the Dimensionless Synthetic <br />~ime-Area Relations for tE~e Clark Unit Hydrograph <br /> Contributing Area, <br /> as a Perce~t of Total Areaa <br />Travel Time, A ~b ~ <br />as a percent of ~~ <br />(1) (2) (3) (4) <br />-------------0 ------------- ------ 0-- - -- 0.0 ------------- --- 0--------- <br />------------10 --------------- ------ 5-- ------------ 4.5 --------------- --- 3--------- <br />- ----- 20 --------------- -----16-- ----------12.6-- - - --- 5------- <br />------------ 30 --------------- -----30-- -----------23=~--------------- --- $--------- <br />------------40 --------------- -----fi5-- -----------35.8--------------- --1?--------- <br />50 <br />- ------------------- 77-- <br />-------- -----------50.0------------- --20- - - <br />------------60--------------- ---- 84-- -----------64-~--------------- --43--------- <br />-----------70-------------- ---- 90-- ----------76.8----------- --~5------- <br />------------ 80 --------------- ---- 94-- -----------$~-4--------------- --90--------- <br />------------ 90 ----------- --- 97-- ---- 95.5 <br />----------------------- 96-------- <br />--- <br />-----------100 --------------- ---100-- --------- 100.0 <br />- - --------------- 100 <br />-------------- <br />a- The dimensionless Synthetic Time-Area relations should be selected as follows: <br />A- The land-use in the watershed or subbasin is urban or predominantly urban. <br />B- All watersheds or subbasins other than those defined for use of curves A or C. <br />C- The watershed or subbasin is mostly undeveloped mountains and/or plains <br />with some interspersed agricultural fields. <br />b- Curve B is the HEC-1 default Time-Area relation and the UA record is not needed as input <br />to the HEC-1 model when using Curve B. <br />19 March 2007 12 <br />