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CITY OP EVERETT STORMWATER MANA6EMENT MANUAL <br /> � Table 5.7 "o" and "k"Values Used in Time Calculatioos tor Hydrographs <br /> Shcet Flow(initia1300 feet of travel) <br /> Surfacc ° <br /> Smooth sur(aces(concrete,asphalt, gravel,compacted soil) OAl l <br /> Fallow fields or loose soil 0.05 <br /> Short praine grass and lawns ���� <br /> Dcnse grasses 0.15 <br /> Bermuda grass 0.24 <br /> Range(natural) OAl <br /> Woods or forest with light underbrush �•�3 <br /> 1Voods or forest with dense underbrush 0.40 ' <br /> Shallow Concentratcd Flow(After the iniNal 300 teet o(sheet Ilow; R=0.1) <br /> Surface k <br /> Forest with heavy ground litter and meadows(n=0.10) 3 <br /> Brushy ground with some trees(n=0.060) 5 <br /> Fallow or minimum tillagc cultivation(n=0.040) 8 <br /> High grass (n=0.035) 9 <br /> Short grass,pasture and lawns (n= � � <br /> �� 0.030) <br /> Nearly bare ground(n=0.25) �3 <br /> Paved and gravel areas(n=0.012) Z� <br /> Intermittent Channel Flow(At the beginning of visible channcls, R=0.2) <br /> Ciiannel Type k <br /> Forestcd swale with hcavy ground littcr(n=0.10) 5 <br /> Foresied drainage couiselravine with dcfincd channel bed(n =0.050) �� <br /> Rock-lined watenvay(n=0.035) 15 <br /> Grassed watcrway(n=0.030) �� <br /> Earth-lincd watcnvay(n=0.025) 20 <br /> C�IP pipc (n -0.024) 2l <br /> Concrctc pipc(n=0.012) `�Z <br /> Othcr watcrways and pipc 0.508'n <br /> Continuaus Strcam Channcl Flow (R=0.4) <br /> ChannclTypc k <br /> Meandcnng svcam with somc pools(n=0.040) Z� <br /> Rock-lined strcam(n =0.035) �3 <br /> Grass-lincd stream(n=0.030) z7 <br /> Other sacams,man-made channels, and pipe 0.807/n <br /> Volume 1-Minimum Technical Requiremenls <br /> 5-9 <br />