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<br />Oak Gulch and Lemon Gulch
<br />Flood Hazard Area Delineation Study
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<br />Contents
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<br />Section Page
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<br />3,7
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<br />~;~~lts p~~'Fi~~~.'.'" ,....... '.::: ::: :::: ::: ::: :::::: :::: ::: :::::: :::::: ::::::: ::::::::: ::::: :::: :::::: :::: ~
<br />3.7.2 Compariso~t~.p~~~;~us Studies ..uou..U.uu.'uUuu...U.UU'H.H..ou.H.HH'H' 5
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<br />1.0 In trod uction ................................................................................................................. 1
<br />I, I Authorization ..u....u,. ..HH..H..H.H.......HHHHHH..."'HH.'.H......u..............HH."H.H.'. I
<br />1.2 Purpose ...h..... .hh.. ..u. .... h... u.ou u......... .... u.. u.... u uou,. ,. H.. H H.,. H'. H H H.......... H.... I
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<br />2.0 Study Area Description .............................................................................................. 1
<br />2, I Topography and Physiography H.H.....HHOU.OUH...hou...OUH.H.H..H.HH.HH.HH.....HH I
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<br />2.2 Soils. H...UO. 'HH .H.... .h'..... 'h"'ou. h. .....' ,.... UOOU h.... ,. H 'H.. .HH' HH., H.... OU......OU H.....H I
<br />23 Surface Water Resources .H.H.HHHH..OU.HH.HH...HOUH..HH...u.............'H.....H.H.HH I
<br />23.1 Stream Characteristics .HOU....H.H.H.OU...HHOUOU.H....h..H.......H.H...H.H..HH I
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<br />23.2 Reservoirs ..... 'H' H." .HH' H.' H' ...... .H'." H. ...... u.. ......... ,. .... H H H.'. H' H H" HH'" 2
<br />233 Diversions .h'.h.h.....h..h..h....:.hh.H......h.h..H.....HHH......OUH..UH....h"h'. 2
<br />2.3.4 Flood History ..OU...h..h..........h.hh.UOou..hHHHH.HHOU.......H.OU......uOU...... 2
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<br />2.4 Vegetation ".H .h..... ,.,. .h.... ou. ou...ou.. .... .hh... u.. ..,... ... H h H H H H.. .H' H..... u... u ......... 2
<br />25 Watershed Imperviousness HHH...'..'.H.HHHHH...HH.H.HHHH......ou....h....H.HHHH... 2
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<br />3.0
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<br />4.0 Hydraulic Analysis...................................................................................................... 6
<br />4.1 Methodology.... u.... u. ou... ouT ....... OU. HH H" H'.' .... ... ...... H.H ........ H.......... ..H. .HH'.' ... 6
<br />4.2 Results H H.....'H. ..HHH..H....OU.u....u.H........OUHH......hh.....HHH.......h 7
<br />43 Generai.6.~~~ie;;' of Flo~d.i~pacts .........H....h.HHH..h..HOU'...H..HHHHH.H...H.... 7
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<br />5.0 References .................................................................................................................... 8
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<br />Tables
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<br />Number
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<br />Page
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<br />Hydrology Analysis ..................................................................................................... 3
<br />3.1 Subwatershedsuo.. ...u. H. H....H... H H.H..H.. H H"HH" HH' HH' "HHOU"'. HH H H H. H H. H H. ..... 3
<br />3.2 Streams. HH..... .UOH H.....H H H' H H H H' .H' "H" H H H HHHHUOUOH UO .H' 'h... H UO. HH' .HH H H.. .... 3
<br />33 Hydrologic Models ...H.H.HUO.HH.HH..HH.H.HH..HHUOUOHh.....H....HHHUOH..H..HHH... 3
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<br />3.4 Rainfall..h...... .u.... ..... ou.. "'''HH uo H...... .......,... ....... H..... H H. .HH'H.H uo .H....... ......... 3
<br />3.4.1 Criteria ..H.UO..OU........ouh.H................'....HHUOH.HH..H.HH.H...u.hu...h...h.. 3
<br />3.4.2 Rainfall Depths H...h.u'..............HH.hh..UOH..H.H..HH.H.H..UU.............H.... 3
<br />3.43 Hyetographs H HHH.HHUO.HHH..UOHHHH....HHHHH.H.H....h.....HUO..HH.HHH.H.. 4
<br />35 CUHP Modeling "H"'HHH.'HH'H.HH.'.H"HH'UOH..HH'HHH'U..UO..'HUHH.HH.'.HH.H.... 4
<br />3.5.1 Delineation ofSubwatersheds..HH.HH...HH.H.Hu.,.,....uHHH.HH...HH..HH.'. 4
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<br />3.5.2 Imperviousness u........... H H......... .H' .H'" u.ouou.. HH.H H.'. H .H' H.' H'.' H H" ou.. 4
<br />3.53 Slope . .......H......HH..'HHH..H....H.HH.HUOHHU.OUU.uu...H.'...HHHH...H.U......,. 4
<br />35.4 Time of Concentration H.H....H.H.HUOUOHHUOH.H.............U....HH..H..HH...... 4
<br />3.55 Retention Storage Losses.H...HH.HHHH..HHuoououu...H.....H..HHHH.u.u...... 5
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<br />3.5.5 Infiltration Losses .'HHH.H.....H.HHHH"...HH.HH.'U......U.HH'.HH.HHH.'.H..... 5
<br />3 ,6 UDSWM2 Modeling. u...... H... ,.. H'. ,. .....,......, h..", H HH. H'.....,.., u u u h...'..,.,. H H..' ,. 5
<br />3.6.1 Conveyance Element Identification Number ..HH..HU....hh....h...'HHHH.. 5
<br />3.6.2 Stream Geometry ....u....u...u..ou...UO'HHH..HH....U.HUUH........u.u.h... 5
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<br />3.63 Roughness HU"" u............,.....,... u U.".H'" .,.. u, H.....'., H.'. ,.,...,.'...... H.'."".' 5
<br />'C . . 5
<br />3,6.4 Routmg onnectlvlty.....,... ... H'.' u u ... u. uu. uh..'.. HH.' H. H'" H.'....,... u.....,.
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<br />3,1 Summary of Area Adjustments.HHuo...H.HH.HHHHH.H..HH...hHH.HH...h.....HHH.Hh.....HHOU 3
<br />3-2 Summary of Unadjusted Rainfall Depths HH.HH..HHUOHH..HHH.HH..H..OU....HH.UO..h.......h 3
<br />3-3 Composite Future Imperviousness ValuesHHHHHHHuo..hHHHHHHHuo.Hu....uoHHH....hHHh 4
<br />3,4 100, Year Peak Discharges at Selected Locations.HuouoH'H'Houhh..hhHH'HHHH".'HH'H'H 5
<br />3,5 Comparison of 100,Year Discharges to Other StudiesHHH...HH..h.hH.hh,HH.Hu.h..H.h.. 6
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<br />Appendices
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<br />Appendix A: Subwatersheds Map (l sheet)
<br />Appendix B: Soils Map (l sheet)
<br />Appendix C: Future Imperviousness Map (l sheet)
<br />Appendix D: Streams Map (l sheet)
<br />Appendix E: Subwatershed Characteristics Table (l sheet)
<br />Appendix F: Stream Characteristics Table (l sheet)
<br />Appendix G: UDSWM2 Connectivity Diagrams (2 sheets)
<br />Appendix H: Peak Discharges Table (I sheet)
<br />Appendix I: Floodplain and Floodway Table (8 sheets)
<br />Appendix J: Floodplain Drawings (50 sheets)
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