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<br />CONTENTS
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<br />Page
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<br />Abstract ,........"."""" ,..,..........,....".. ,........,.",.... ,.....,....,..,.......... ,.,.." ,...... ,........, ........."".,.",.." ,.............. ......... I
<br />Introduction...",.,.."" ,...,......,...,...."" .........,.."......,.... ...., ....,..........",.. .......,........, .....,...."",.."".... ,.........,.. ,........ 2
<br />Purpose and scope......,........"....,.,....,..".. ....,.... ....,..,....".... ,.... ,...... ......,.,." ,..,...."",...."...... ,.........,...... ,..., 2
<br />Description of the study area ,..,......,.,.."..,............, ..,...."",........,........,.."..,.....,...,..,.,..""....,..................... 4
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<br />Previous investigations ............ ..... ,.......... ,_ ,., _,.. ..... ............. ,.... ,_ ..... ................................... ... ...... ...... ......... 5
<br />Data collection and analysis,.,.,..""....,....,.,.,.... ,............, ....,.,.."....",.. ,.... ,..........,...,.,.,.""""""...., ...... ..., ........... 5
<br />Hydraulic data. ,..........,......""....,......,..........,........, ....,...."....,..".......,...""""........"",.."".. .... ....,.,.,.........., 5
<br />Stream power and shear stress"...,....,.,.",....,.."....".....,.."....,..".........,......,.......""".,..""......,..........,......., 6
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<br />Vegetation data ,...",........'........"..,....,....,'.. ,...."....,......,........,..".........,.,.,.., ,.........'"......""...... ,.....,.........., 6
<br />Vegetation-susceptibility index...",......",.. ,.."....,........,.."....,.. .........,.....,...,."......""...... ,.............. ,.. 6
<br />Vegetation-flexibility factor....,....".... ,.."....",....,..",'..,........,.... ....,.,......,...."..,...."............ ,.......... ,.. 9
<br />Vegetation-blocking coefficient,.."...... ,......",......,.",..,...."..",......,...,......,.." .......,'..',................... ,.. 12
<br />Vegetation-distribution coefficient,.."....,.."",.... ,...."....,.",..,..',.... ,...... ,........ ....,..".",................... ,.. 12
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<br />Flow-depth coefficient........,.... ........."....,..""",....,..',....,..".."",......,........'.... ,.........."".."......"",..", 14
<br />Relation between stream power and vegetation-susceptibility index..........................,.................... 14
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<br />Vegetation removal"",.... ....,..""",........,."", ,....",.."......,.,.,..,....'".."......,.......... ,.,....,......'",.."......",....", 14
<br />Critical shear stress ........,.."",......,......"..,..",..........,......,...""""........."....,.... ....,...,.."".."....,.."""", 18
<br />Flow duration,...."""......,..",.."".. ,......',..,....,.."......,......,....",.."....,...."........'.. ,..........".."......"",..", 18
<br />Effects of flow-induced vegetation changes on channel conveyance,......,..............,........,...............,..,............. 20
<br />Components of Manning's n ..,..",..""....,...",..,..",.."......,.",..,....",.."......,.."..".......,.....,....""""..,....',..", 20
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<br />Base value of Manning's n "...."..,......"..,..",.."......,........,."".."......,.."........,....,......""..""....,...,."" 20
<br />Adjustment for vegetation component., ,......,.."......,......,.."..,..""....,.."........,.. ,.....,.."""""..,.........., 20
<br />Channel-conveyance computations"",' ......." ....,..,."",.... ,........,..",."",........"",.. ,..........,.,.",..""..,........." 21
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<br />Discussion and example case. .............. ........... .........'...... ......... .........,.. ,_ ,_.................... ........."...... n.......... 21
<br />Assumptions and limitations,..""......",..,."", .......', ....,..,.."""....,.." ,......,...",........'""....,..........,......""",.........., 26
<br />Sunmurry ,.............. ,...,.. .......".."......,.."..,..".. ....,..".. ,....,......"....,........,..,.."""......,.."...."",.... ,.....,...,.,....,...,..... 27
<br />Selected references..,.."..,.."".."........"".""", ,......"..,..."."",....,.... ,........,.."""......,.."....,.."...... ,..............,........, 27
<br />Basic data........ ,.....,....",......"."",......""..".... ......... ....,..,..."",....,........,..,.."""".. ,...."....,............,..............,....... 31
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<br />FIGURES
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<br />I. Map showing study area and selected sites in central Arizona..........................,......,.......................... 3
<br />2. Photograph showing dynamometers used to determine vegetation bending-moment values.............. 9
<br />3. Graph showing bending-moment values for four types of vegetation in
<br />
<br />central Arizona.... ...,...""",....,....,.."""....,..',.. ,......,...",....",..,'..,.. ,.....,.,.."......, ...............""""",......',.. 10
<br />4--7. Photographs showing:
<br />4. A lone willow approximately 15 feet tall in a prone position after the flow of
<br />September 10, 1994, Vekol Wash near Stanfield ..........................,..........................,................, II
<br />5. An erect, 16-foot-tall palo verde after the flow of January 8,1993,
<br />Cave Creek above New River Road .......................................................,................................... II
<br />6, Spatial distribution of vegetation in stream channels:
<br />A, Vegetation aligned parallel to flow..............................,.........................,............................ 13
<br />B, Randomly distributed vegetation.""""......"",..,..."""""....,..".."..,............,............,.....,...., 13
<br />7, Saltcedar that was little affected by flow primarily because of the relatively
<br />low ratio of flow depth to vegetation heighL............................................................................ 15
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<br />Contents III
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