river stability daverosgen wildland hydrology · distribution along river reaches and mapping...
TRANSCRIPT
River Stability
Field uide
DaveRosgen Wildland Hydrology
Fort Collins Colorado
Jlfustrations
Hilton lee Silvey Western Hydrology
Lakewood Colorado
Technical Editing
Darcie Frantila Wildland Hydrology
Fort Collins Colorado
Cover photograph of Weminuche Creek Colorado Photograph taken by Aaron Kopp
Rosgen Dave 1942shyRiver Stability Field Guide
ISBN-13 978-0-9791308-1-6 ISBN-10 0-9791308-1-6
Includes References and Glossary 1 Geomorphology 2 Hydrology 3 Fisheries Management 4 Watershed Science 5 Sedimentology 6 Environmental Engineering
Prepress (including page layout design and cover design) Darcie Frantila Wildland Hydrology Fort Collins Colorado Printing Color House Graphics Grand Rapids Michigan
Copyrightcopy 2008 by Wildland Hydrology 11210 N County Rd 19 Fort Collins Colorado
All Illustrations Copyrightcopy Hilton Lee Silvey
No part of this book may be reproduced by any mechanical photographic or electronic process nor can it be stored in a retrieval system transmitted or otherwise copied for public or private use without written permission from the publisher
Printed in the United States of America
Table ofContents
b Flow Regime 3-10 c Stream Order and Stream Size 3-14 d Meander Patterns 3-16 e Depositional Patterns 3-19 f Channel Blockages 3-25 g Degree ofChannellncision 3-32 h WidthDepth Ratio State 3-37 i Degree ofChannel Confinement (Lateral Containment) 3-41 j Modified Pfankuch Channel Stability Rating 3-45
The BANCS Model to Predict Streambank Erosion 3-50 The Bank Erosion Hazard Index (BEHI) 3-52
1 Study Bank-Height Ratio 3-58 2 Root Depth Ratio 3-60
3 Weighted Root Density 3-60 4 Bank Angle 3-65 5 Surface Protection 3-67
6 Bank Material Adjustment 3-68 7 Stratification Adjustment 3-70
NBSMethod 1 ChannelPattern Transverse BarorSplitChannellCentral
Sediment Transport Capacity The FLOWSED and
Near-Bank Stress (NBS) 3-71
BarCreating NBS orHigh Velocity Gradient 3-73 NBSMethod2 RatioofRadiusofCurvaturetoBankfuiWidth 3-75
NBSMethod3 RatioofPooSopetoAverageSope 3-76 NBSMethod 4 Ratio ofPoolSlope to RiffleSlope 3-77
NBSMethodS RatioofNear-BankMaxDepthtoBankfuiMeanDepth 3-78
NBS Method6 Ratio ofNear-Bank ShearStress to BankfullShearStress 3-80 NBSMethod7 VelocityProfilesllsovesNelocityGradient middot 3-82
PredictAnnualStreambankErosion Rate Using BEHI andNBS Ratings 3-86 BANCS Model Example Alamosa River XS-0 3-90
Sediment Competence I Entrainment 3-98 Bar Sample and Sub-Pavement Sample 3-103
POWERSED Models 3-109 viii
Bank Erosion Prediction (BEHI NBS) I W ARSSS IUS EPA Page 1 of3
Water WARSSS You are here WaterraquoScience amp TechnologynAoplicalions amp DatabasesraquoTechnlcal ToolsraquoIJAHSSS raquoBank Erosion Prediction (BEHI NBS)
Bank Erosion Prediction (BEHI NBS) The prediction of stream bank erosion rates uses the Bank Assessment for Non-point source Consequences of
Sediment (BANCS) method This method as published by Rosgen (2001a) utilizes 110 bank erodibility estimation tools the Bank
Erosion Hazard Index (BE HI) and Near Bank Stress (NBS) The application involves evaluating the bank characterisUcs and flow
distribution along river reaches and mapping various risk ratings commensurate vvith bank and channel changes AA estimate of
erosion rate Is made and then muttiplied times the bank height limes the length of bank of a similar condition providing an estimate of
cubic yards andor tons of sedimenVyear This information can be compared to the sediment yield data to apporticn the amount of
sediment potentially contributed by streambanks
The relationships developed to convert measurements of slreambank variables into risk categories are shown along lith bank erosion
and bank angle illustrations in Figures 112o 114 Rosgen 200a) A sketch of a streambank and some of the variables surveyed
and calculated Is shown in Worksheet 20 (PDF 38 kb 1 p) The use of channel materials bank stratification and all of the variable
ratios and ranges are summarized In the Bank Erosion Hazard Index BEHI) form (Worksheet 21 PDF 40 kb 1 p)
Figure 112 Streambank erodibility criteria used for the BEHI rating fRosgen 1996 2001al
J lt ~ z w
1 0 ~ w lt z lt m
Figure 113 Illustrated examples of the flve BEHI criteria
Five Common Bank Angle Scenarios
About PDF Files
Prediction le~el Assessment
Steps
HY_-lL9l9_llL8~t~_tlg_n_S
J___IJSGS R_gpolt1a C8~ 2 Drainage Arearat
3 F1ehi Crthrtif(l
4 F113 DelefFnBIJCrl
sectlf_fJ)_J__QQilO_I_)_gy
~ ~i~sectJflJ_I~SSfiC91QC
tLQ_flSpound15_LgtDQ~__8_]_t_sl_~
sectability Anal~
7 Channel Sab~ty
8 Bank Erosion PredicMn
___ll_~~JffilQ[J~_lt~
fiogtYLfiQQ_i)_Q__n_t_B__elJj__)Jsect
Sediment Rating Curves
10 Fklw Modfi-cakbulll~
11 Dimensionless Flow
12 Bankfull 0 amp Sediment
13 Dimensionless SRCs
14 Bedload Rating
15 Fkrv DuraUon Curves
16 FlowmiddotRelated Y1eld
17 flow-Related Increases
Supply Changes
16 Channel Changes
19_ Bedlcad Transoort
20 Hbullllslooe Processes 21 Hillslooe Sediment
22 Entrainment Calculation
Stabititv Consequences
23 Sed_ Transport Chaooes
24 Aggradation Potential
25 Dooradation
26 Enlamement
SummarvAnalysls
27 State Shift
28 Total Sediment
29 DeMrture Analysis
3010 loads by Categorv
Many of the docume-nts fsled on this s1te are POF flies Vewing a PDF fle re-wires use of Adobes free
Acrobat Reader software EPAs PDF page provides inormahon on downloading the software
http water epa gov Isci tech dataittoo1swarssspla _box OS cfm 582014
Bank Erosion Prediction (BEHI NBS) IWARSSS IUS EPA Page 2 of3
Figure 114 Common bank angle scenarios
Woruheet 20 Clid(1 ~~-
middotmiddotmiddot-~-middot--middot~middot-middot~~--middot-middotmiddotmiddot - shy
Table 18 Velocity gradient and near-btnk stress Indices ~21ClkOiifWBenk Erosion Velocity Near~bank stressshear
RiskRetinq Gradient stress Very low Less them 05 less than 08
Low 05 -1 0 06- L05 Moderate U-16 106 -114
Hiqh 161 -20 U5-119 VeryHiqh 21-24 12- L6 Extreme Greater than 24 Greater then 160
The Near-Bank Stress (NBS) variables used in the prediction methodology indicate potential disproportionate energy distribution In the near-bank region (113 of channel cross-section associated with the bank being evaluated) Changes in near-bank stress can accelerate streambank erosion The initial criteria for NBS are summarized In Rosgen (1996 2001a) and shown In Table 18 Additional criteria shown in Worksheet 22 below were established to assist in the field determination of NBS for a variety of Inventory levels Use Worksheet 22a PDF 39kb 1 p) to complete an NBS rating using the methods 1-7) appropriate for the available data Use the conversion table in Worksheet 22a to determine and record the final NBS rating for impaired and reference reaches
It Is Imperative to also plot the BE HI and NBS ratings on a photo or map In order to Identify specific locations In need of mitigation restoration or changed riparian management
httpwaterepagovsci tech dataittoolswarssspla_box08cfm 582014
Bank Erosion Prediction (BEHI NBS) I W ARSSS IUS EPA Page 3 of3
Slrum BEHJ A ectNe
Bank- tlur fhrk Str~$$ M ect~gtoe +Toe Pnl Stahltlo Prelt$cted Erlt)sioo ~ Tee Pin Elfiyen3ioo t Mnsur~d EngtSicent11 f
Date Illite Horiiont~l Venlual Hotu Horhont~l Vertical tfotes
-----
Veulcalllank Pronle Strum OMe
6 -middot- --middot -middotmiddot- ---- -middotmiddotmiddot I
liorirontal Distance tfl)
The oombinatlon of BEHI and NBS risk ratings were used to develop the relations shown In Figure 116 (PDF 303 kb lp) (Colorado data) and in Figure 116 (PDF 507 kb 1p) (Yellowstone National Park data) These
rela~ons indicated a statisUcaly valid way of predicting annual streambank erosion rate in feelyear using BEHI and NBS ratings middot (Rosgen 1996 2001a) This allows the user to predict annual streambank
middot erosion rates to help apportion annual sediment yields to various sources The relations for Colorado (sedimentary and metamorphic) and Yellowstone (volcanism and alpine glaciation) are not intended to be
-universal for alluvium but rather provide a framework for other to develop Figure 115 Cid 10 view similar relations or validate these relations locally The application of these fJQure 116 Clid to view
relations allows the field practitioner to obtain BEHI and NBS ratings along river reaches of varying conditlonlt is imperative to plot these ratings also on a photo or map in order to identify specific locations in need of mitigation restoration or changed riparian management RelUIJllt1 Main Flowchart N0ld to Next Step
hltpwater epa govlscilechldalaitltoolsJwarsssfpla _box08cfm
http water epagovscitech datai ttoolswarsssp Ia_box08cfm 582014
- barcode 557062
- barcodetext SDMS Doc ID 557062
Cover photograph of Weminuche Creek Colorado Photograph taken by Aaron Kopp
Rosgen Dave 1942shyRiver Stability Field Guide
ISBN-13 978-0-9791308-1-6 ISBN-10 0-9791308-1-6
Includes References and Glossary 1 Geomorphology 2 Hydrology 3 Fisheries Management 4 Watershed Science 5 Sedimentology 6 Environmental Engineering
Prepress (including page layout design and cover design) Darcie Frantila Wildland Hydrology Fort Collins Colorado Printing Color House Graphics Grand Rapids Michigan
Copyrightcopy 2008 by Wildland Hydrology 11210 N County Rd 19 Fort Collins Colorado
All Illustrations Copyrightcopy Hilton Lee Silvey
No part of this book may be reproduced by any mechanical photographic or electronic process nor can it be stored in a retrieval system transmitted or otherwise copied for public or private use without written permission from the publisher
Printed in the United States of America
Table ofContents
b Flow Regime 3-10 c Stream Order and Stream Size 3-14 d Meander Patterns 3-16 e Depositional Patterns 3-19 f Channel Blockages 3-25 g Degree ofChannellncision 3-32 h WidthDepth Ratio State 3-37 i Degree ofChannel Confinement (Lateral Containment) 3-41 j Modified Pfankuch Channel Stability Rating 3-45
The BANCS Model to Predict Streambank Erosion 3-50 The Bank Erosion Hazard Index (BEHI) 3-52
1 Study Bank-Height Ratio 3-58 2 Root Depth Ratio 3-60
3 Weighted Root Density 3-60 4 Bank Angle 3-65 5 Surface Protection 3-67
6 Bank Material Adjustment 3-68 7 Stratification Adjustment 3-70
NBSMethod 1 ChannelPattern Transverse BarorSplitChannellCentral
Sediment Transport Capacity The FLOWSED and
Near-Bank Stress (NBS) 3-71
BarCreating NBS orHigh Velocity Gradient 3-73 NBSMethod2 RatioofRadiusofCurvaturetoBankfuiWidth 3-75
NBSMethod3 RatioofPooSopetoAverageSope 3-76 NBSMethod 4 Ratio ofPoolSlope to RiffleSlope 3-77
NBSMethodS RatioofNear-BankMaxDepthtoBankfuiMeanDepth 3-78
NBS Method6 Ratio ofNear-Bank ShearStress to BankfullShearStress 3-80 NBSMethod7 VelocityProfilesllsovesNelocityGradient middot 3-82
PredictAnnualStreambankErosion Rate Using BEHI andNBS Ratings 3-86 BANCS Model Example Alamosa River XS-0 3-90
Sediment Competence I Entrainment 3-98 Bar Sample and Sub-Pavement Sample 3-103
POWERSED Models 3-109 viii
Bank Erosion Prediction (BEHI NBS) I W ARSSS IUS EPA Page 1 of3
Water WARSSS You are here WaterraquoScience amp TechnologynAoplicalions amp DatabasesraquoTechnlcal ToolsraquoIJAHSSS raquoBank Erosion Prediction (BEHI NBS)
Bank Erosion Prediction (BEHI NBS) The prediction of stream bank erosion rates uses the Bank Assessment for Non-point source Consequences of
Sediment (BANCS) method This method as published by Rosgen (2001a) utilizes 110 bank erodibility estimation tools the Bank
Erosion Hazard Index (BE HI) and Near Bank Stress (NBS) The application involves evaluating the bank characterisUcs and flow
distribution along river reaches and mapping various risk ratings commensurate vvith bank and channel changes AA estimate of
erosion rate Is made and then muttiplied times the bank height limes the length of bank of a similar condition providing an estimate of
cubic yards andor tons of sedimenVyear This information can be compared to the sediment yield data to apporticn the amount of
sediment potentially contributed by streambanks
The relationships developed to convert measurements of slreambank variables into risk categories are shown along lith bank erosion
and bank angle illustrations in Figures 112o 114 Rosgen 200a) A sketch of a streambank and some of the variables surveyed
and calculated Is shown in Worksheet 20 (PDF 38 kb 1 p) The use of channel materials bank stratification and all of the variable
ratios and ranges are summarized In the Bank Erosion Hazard Index BEHI) form (Worksheet 21 PDF 40 kb 1 p)
Figure 112 Streambank erodibility criteria used for the BEHI rating fRosgen 1996 2001al
J lt ~ z w
1 0 ~ w lt z lt m
Figure 113 Illustrated examples of the flve BEHI criteria
Five Common Bank Angle Scenarios
About PDF Files
Prediction le~el Assessment
Steps
HY_-lL9l9_llL8~t~_tlg_n_S
J___IJSGS R_gpolt1a C8~ 2 Drainage Arearat
3 F1ehi Crthrtif(l
4 F113 DelefFnBIJCrl
sectlf_fJ)_J__QQilO_I_)_gy
~ ~i~sectJflJ_I~SSfiC91QC
tLQ_flSpound15_LgtDQ~__8_]_t_sl_~
sectability Anal~
7 Channel Sab~ty
8 Bank Erosion PredicMn
___ll_~~JffilQ[J~_lt~
fiogtYLfiQQ_i)_Q__n_t_B__elJj__)Jsect
Sediment Rating Curves
10 Fklw Modfi-cakbulll~
11 Dimensionless Flow
12 Bankfull 0 amp Sediment
13 Dimensionless SRCs
14 Bedload Rating
15 Fkrv DuraUon Curves
16 FlowmiddotRelated Y1eld
17 flow-Related Increases
Supply Changes
16 Channel Changes
19_ Bedlcad Transoort
20 Hbullllslooe Processes 21 Hillslooe Sediment
22 Entrainment Calculation
Stabititv Consequences
23 Sed_ Transport Chaooes
24 Aggradation Potential
25 Dooradation
26 Enlamement
SummarvAnalysls
27 State Shift
28 Total Sediment
29 DeMrture Analysis
3010 loads by Categorv
Many of the docume-nts fsled on this s1te are POF flies Vewing a PDF fle re-wires use of Adobes free
Acrobat Reader software EPAs PDF page provides inormahon on downloading the software
http water epa gov Isci tech dataittoo1swarssspla _box OS cfm 582014
Bank Erosion Prediction (BEHI NBS) IWARSSS IUS EPA Page 2 of3
Figure 114 Common bank angle scenarios
Woruheet 20 Clid(1 ~~-
middotmiddotmiddot-~-middot--middot~middot-middot~~--middot-middotmiddotmiddot - shy
Table 18 Velocity gradient and near-btnk stress Indices ~21ClkOiifWBenk Erosion Velocity Near~bank stressshear
RiskRetinq Gradient stress Very low Less them 05 less than 08
Low 05 -1 0 06- L05 Moderate U-16 106 -114
Hiqh 161 -20 U5-119 VeryHiqh 21-24 12- L6 Extreme Greater than 24 Greater then 160
The Near-Bank Stress (NBS) variables used in the prediction methodology indicate potential disproportionate energy distribution In the near-bank region (113 of channel cross-section associated with the bank being evaluated) Changes in near-bank stress can accelerate streambank erosion The initial criteria for NBS are summarized In Rosgen (1996 2001a) and shown In Table 18 Additional criteria shown in Worksheet 22 below were established to assist in the field determination of NBS for a variety of Inventory levels Use Worksheet 22a PDF 39kb 1 p) to complete an NBS rating using the methods 1-7) appropriate for the available data Use the conversion table in Worksheet 22a to determine and record the final NBS rating for impaired and reference reaches
It Is Imperative to also plot the BE HI and NBS ratings on a photo or map In order to Identify specific locations In need of mitigation restoration or changed riparian management
httpwaterepagovsci tech dataittoolswarssspla_box08cfm 582014
Bank Erosion Prediction (BEHI NBS) I W ARSSS IUS EPA Page 3 of3
Slrum BEHJ A ectNe
Bank- tlur fhrk Str~$$ M ect~gtoe +Toe Pnl Stahltlo Prelt$cted Erlt)sioo ~ Tee Pin Elfiyen3ioo t Mnsur~d EngtSicent11 f
Date Illite Horiiont~l Venlual Hotu Horhont~l Vertical tfotes
-----
Veulcalllank Pronle Strum OMe
6 -middot- --middot -middotmiddot- ---- -middotmiddotmiddot I
liorirontal Distance tfl)
The oombinatlon of BEHI and NBS risk ratings were used to develop the relations shown In Figure 116 (PDF 303 kb lp) (Colorado data) and in Figure 116 (PDF 507 kb 1p) (Yellowstone National Park data) These
rela~ons indicated a statisUcaly valid way of predicting annual streambank erosion rate in feelyear using BEHI and NBS ratings middot (Rosgen 1996 2001a) This allows the user to predict annual streambank
middot erosion rates to help apportion annual sediment yields to various sources The relations for Colorado (sedimentary and metamorphic) and Yellowstone (volcanism and alpine glaciation) are not intended to be
-universal for alluvium but rather provide a framework for other to develop Figure 115 Cid 10 view similar relations or validate these relations locally The application of these fJQure 116 Clid to view
relations allows the field practitioner to obtain BEHI and NBS ratings along river reaches of varying conditlonlt is imperative to plot these ratings also on a photo or map in order to identify specific locations in need of mitigation restoration or changed riparian management RelUIJllt1 Main Flowchart N0ld to Next Step
hltpwater epa govlscilechldalaitltoolsJwarsssfpla _box08cfm
http water epagovscitech datai ttoolswarsssp Ia_box08cfm 582014
- barcode 557062
- barcodetext SDMS Doc ID 557062
Table ofContents
b Flow Regime 3-10 c Stream Order and Stream Size 3-14 d Meander Patterns 3-16 e Depositional Patterns 3-19 f Channel Blockages 3-25 g Degree ofChannellncision 3-32 h WidthDepth Ratio State 3-37 i Degree ofChannel Confinement (Lateral Containment) 3-41 j Modified Pfankuch Channel Stability Rating 3-45
The BANCS Model to Predict Streambank Erosion 3-50 The Bank Erosion Hazard Index (BEHI) 3-52
1 Study Bank-Height Ratio 3-58 2 Root Depth Ratio 3-60
3 Weighted Root Density 3-60 4 Bank Angle 3-65 5 Surface Protection 3-67
6 Bank Material Adjustment 3-68 7 Stratification Adjustment 3-70
NBSMethod 1 ChannelPattern Transverse BarorSplitChannellCentral
Sediment Transport Capacity The FLOWSED and
Near-Bank Stress (NBS) 3-71
BarCreating NBS orHigh Velocity Gradient 3-73 NBSMethod2 RatioofRadiusofCurvaturetoBankfuiWidth 3-75
NBSMethod3 RatioofPooSopetoAverageSope 3-76 NBSMethod 4 Ratio ofPoolSlope to RiffleSlope 3-77
NBSMethodS RatioofNear-BankMaxDepthtoBankfuiMeanDepth 3-78
NBS Method6 Ratio ofNear-Bank ShearStress to BankfullShearStress 3-80 NBSMethod7 VelocityProfilesllsovesNelocityGradient middot 3-82
PredictAnnualStreambankErosion Rate Using BEHI andNBS Ratings 3-86 BANCS Model Example Alamosa River XS-0 3-90
Sediment Competence I Entrainment 3-98 Bar Sample and Sub-Pavement Sample 3-103
POWERSED Models 3-109 viii
Bank Erosion Prediction (BEHI NBS) I W ARSSS IUS EPA Page 1 of3
Water WARSSS You are here WaterraquoScience amp TechnologynAoplicalions amp DatabasesraquoTechnlcal ToolsraquoIJAHSSS raquoBank Erosion Prediction (BEHI NBS)
Bank Erosion Prediction (BEHI NBS) The prediction of stream bank erosion rates uses the Bank Assessment for Non-point source Consequences of
Sediment (BANCS) method This method as published by Rosgen (2001a) utilizes 110 bank erodibility estimation tools the Bank
Erosion Hazard Index (BE HI) and Near Bank Stress (NBS) The application involves evaluating the bank characterisUcs and flow
distribution along river reaches and mapping various risk ratings commensurate vvith bank and channel changes AA estimate of
erosion rate Is made and then muttiplied times the bank height limes the length of bank of a similar condition providing an estimate of
cubic yards andor tons of sedimenVyear This information can be compared to the sediment yield data to apporticn the amount of
sediment potentially contributed by streambanks
The relationships developed to convert measurements of slreambank variables into risk categories are shown along lith bank erosion
and bank angle illustrations in Figures 112o 114 Rosgen 200a) A sketch of a streambank and some of the variables surveyed
and calculated Is shown in Worksheet 20 (PDF 38 kb 1 p) The use of channel materials bank stratification and all of the variable
ratios and ranges are summarized In the Bank Erosion Hazard Index BEHI) form (Worksheet 21 PDF 40 kb 1 p)
Figure 112 Streambank erodibility criteria used for the BEHI rating fRosgen 1996 2001al
J lt ~ z w
1 0 ~ w lt z lt m
Figure 113 Illustrated examples of the flve BEHI criteria
Five Common Bank Angle Scenarios
About PDF Files
Prediction le~el Assessment
Steps
HY_-lL9l9_llL8~t~_tlg_n_S
J___IJSGS R_gpolt1a C8~ 2 Drainage Arearat
3 F1ehi Crthrtif(l
4 F113 DelefFnBIJCrl
sectlf_fJ)_J__QQilO_I_)_gy
~ ~i~sectJflJ_I~SSfiC91QC
tLQ_flSpound15_LgtDQ~__8_]_t_sl_~
sectability Anal~
7 Channel Sab~ty
8 Bank Erosion PredicMn
___ll_~~JffilQ[J~_lt~
fiogtYLfiQQ_i)_Q__n_t_B__elJj__)Jsect
Sediment Rating Curves
10 Fklw Modfi-cakbulll~
11 Dimensionless Flow
12 Bankfull 0 amp Sediment
13 Dimensionless SRCs
14 Bedload Rating
15 Fkrv DuraUon Curves
16 FlowmiddotRelated Y1eld
17 flow-Related Increases
Supply Changes
16 Channel Changes
19_ Bedlcad Transoort
20 Hbullllslooe Processes 21 Hillslooe Sediment
22 Entrainment Calculation
Stabititv Consequences
23 Sed_ Transport Chaooes
24 Aggradation Potential
25 Dooradation
26 Enlamement
SummarvAnalysls
27 State Shift
28 Total Sediment
29 DeMrture Analysis
3010 loads by Categorv
Many of the docume-nts fsled on this s1te are POF flies Vewing a PDF fle re-wires use of Adobes free
Acrobat Reader software EPAs PDF page provides inormahon on downloading the software
http water epa gov Isci tech dataittoo1swarssspla _box OS cfm 582014
Bank Erosion Prediction (BEHI NBS) IWARSSS IUS EPA Page 2 of3
Figure 114 Common bank angle scenarios
Woruheet 20 Clid(1 ~~-
middotmiddotmiddot-~-middot--middot~middot-middot~~--middot-middotmiddotmiddot - shy
Table 18 Velocity gradient and near-btnk stress Indices ~21ClkOiifWBenk Erosion Velocity Near~bank stressshear
RiskRetinq Gradient stress Very low Less them 05 less than 08
Low 05 -1 0 06- L05 Moderate U-16 106 -114
Hiqh 161 -20 U5-119 VeryHiqh 21-24 12- L6 Extreme Greater than 24 Greater then 160
The Near-Bank Stress (NBS) variables used in the prediction methodology indicate potential disproportionate energy distribution In the near-bank region (113 of channel cross-section associated with the bank being evaluated) Changes in near-bank stress can accelerate streambank erosion The initial criteria for NBS are summarized In Rosgen (1996 2001a) and shown In Table 18 Additional criteria shown in Worksheet 22 below were established to assist in the field determination of NBS for a variety of Inventory levels Use Worksheet 22a PDF 39kb 1 p) to complete an NBS rating using the methods 1-7) appropriate for the available data Use the conversion table in Worksheet 22a to determine and record the final NBS rating for impaired and reference reaches
It Is Imperative to also plot the BE HI and NBS ratings on a photo or map In order to Identify specific locations In need of mitigation restoration or changed riparian management
httpwaterepagovsci tech dataittoolswarssspla_box08cfm 582014
Bank Erosion Prediction (BEHI NBS) I W ARSSS IUS EPA Page 3 of3
Slrum BEHJ A ectNe
Bank- tlur fhrk Str~$$ M ect~gtoe +Toe Pnl Stahltlo Prelt$cted Erlt)sioo ~ Tee Pin Elfiyen3ioo t Mnsur~d EngtSicent11 f
Date Illite Horiiont~l Venlual Hotu Horhont~l Vertical tfotes
-----
Veulcalllank Pronle Strum OMe
6 -middot- --middot -middotmiddot- ---- -middotmiddotmiddot I
liorirontal Distance tfl)
The oombinatlon of BEHI and NBS risk ratings were used to develop the relations shown In Figure 116 (PDF 303 kb lp) (Colorado data) and in Figure 116 (PDF 507 kb 1p) (Yellowstone National Park data) These
rela~ons indicated a statisUcaly valid way of predicting annual streambank erosion rate in feelyear using BEHI and NBS ratings middot (Rosgen 1996 2001a) This allows the user to predict annual streambank
middot erosion rates to help apportion annual sediment yields to various sources The relations for Colorado (sedimentary and metamorphic) and Yellowstone (volcanism and alpine glaciation) are not intended to be
-universal for alluvium but rather provide a framework for other to develop Figure 115 Cid 10 view similar relations or validate these relations locally The application of these fJQure 116 Clid to view
relations allows the field practitioner to obtain BEHI and NBS ratings along river reaches of varying conditlonlt is imperative to plot these ratings also on a photo or map in order to identify specific locations in need of mitigation restoration or changed riparian management RelUIJllt1 Main Flowchart N0ld to Next Step
hltpwater epa govlscilechldalaitltoolsJwarsssfpla _box08cfm
http water epagovscitech datai ttoolswarsssp Ia_box08cfm 582014
- barcode 557062
- barcodetext SDMS Doc ID 557062
Bank Erosion Prediction (BEHI NBS) I W ARSSS IUS EPA Page 1 of3
Water WARSSS You are here WaterraquoScience amp TechnologynAoplicalions amp DatabasesraquoTechnlcal ToolsraquoIJAHSSS raquoBank Erosion Prediction (BEHI NBS)
Bank Erosion Prediction (BEHI NBS) The prediction of stream bank erosion rates uses the Bank Assessment for Non-point source Consequences of
Sediment (BANCS) method This method as published by Rosgen (2001a) utilizes 110 bank erodibility estimation tools the Bank
Erosion Hazard Index (BE HI) and Near Bank Stress (NBS) The application involves evaluating the bank characterisUcs and flow
distribution along river reaches and mapping various risk ratings commensurate vvith bank and channel changes AA estimate of
erosion rate Is made and then muttiplied times the bank height limes the length of bank of a similar condition providing an estimate of
cubic yards andor tons of sedimenVyear This information can be compared to the sediment yield data to apporticn the amount of
sediment potentially contributed by streambanks
The relationships developed to convert measurements of slreambank variables into risk categories are shown along lith bank erosion
and bank angle illustrations in Figures 112o 114 Rosgen 200a) A sketch of a streambank and some of the variables surveyed
and calculated Is shown in Worksheet 20 (PDF 38 kb 1 p) The use of channel materials bank stratification and all of the variable
ratios and ranges are summarized In the Bank Erosion Hazard Index BEHI) form (Worksheet 21 PDF 40 kb 1 p)
Figure 112 Streambank erodibility criteria used for the BEHI rating fRosgen 1996 2001al
J lt ~ z w
1 0 ~ w lt z lt m
Figure 113 Illustrated examples of the flve BEHI criteria
Five Common Bank Angle Scenarios
About PDF Files
Prediction le~el Assessment
Steps
HY_-lL9l9_llL8~t~_tlg_n_S
J___IJSGS R_gpolt1a C8~ 2 Drainage Arearat
3 F1ehi Crthrtif(l
4 F113 DelefFnBIJCrl
sectlf_fJ)_J__QQilO_I_)_gy
~ ~i~sectJflJ_I~SSfiC91QC
tLQ_flSpound15_LgtDQ~__8_]_t_sl_~
sectability Anal~
7 Channel Sab~ty
8 Bank Erosion PredicMn
___ll_~~JffilQ[J~_lt~
fiogtYLfiQQ_i)_Q__n_t_B__elJj__)Jsect
Sediment Rating Curves
10 Fklw Modfi-cakbulll~
11 Dimensionless Flow
12 Bankfull 0 amp Sediment
13 Dimensionless SRCs
14 Bedload Rating
15 Fkrv DuraUon Curves
16 FlowmiddotRelated Y1eld
17 flow-Related Increases
Supply Changes
16 Channel Changes
19_ Bedlcad Transoort
20 Hbullllslooe Processes 21 Hillslooe Sediment
22 Entrainment Calculation
Stabititv Consequences
23 Sed_ Transport Chaooes
24 Aggradation Potential
25 Dooradation
26 Enlamement
SummarvAnalysls
27 State Shift
28 Total Sediment
29 DeMrture Analysis
3010 loads by Categorv
Many of the docume-nts fsled on this s1te are POF flies Vewing a PDF fle re-wires use of Adobes free
Acrobat Reader software EPAs PDF page provides inormahon on downloading the software
http water epa gov Isci tech dataittoo1swarssspla _box OS cfm 582014
Bank Erosion Prediction (BEHI NBS) IWARSSS IUS EPA Page 2 of3
Figure 114 Common bank angle scenarios
Woruheet 20 Clid(1 ~~-
middotmiddotmiddot-~-middot--middot~middot-middot~~--middot-middotmiddotmiddot - shy
Table 18 Velocity gradient and near-btnk stress Indices ~21ClkOiifWBenk Erosion Velocity Near~bank stressshear
RiskRetinq Gradient stress Very low Less them 05 less than 08
Low 05 -1 0 06- L05 Moderate U-16 106 -114
Hiqh 161 -20 U5-119 VeryHiqh 21-24 12- L6 Extreme Greater than 24 Greater then 160
The Near-Bank Stress (NBS) variables used in the prediction methodology indicate potential disproportionate energy distribution In the near-bank region (113 of channel cross-section associated with the bank being evaluated) Changes in near-bank stress can accelerate streambank erosion The initial criteria for NBS are summarized In Rosgen (1996 2001a) and shown In Table 18 Additional criteria shown in Worksheet 22 below were established to assist in the field determination of NBS for a variety of Inventory levels Use Worksheet 22a PDF 39kb 1 p) to complete an NBS rating using the methods 1-7) appropriate for the available data Use the conversion table in Worksheet 22a to determine and record the final NBS rating for impaired and reference reaches
It Is Imperative to also plot the BE HI and NBS ratings on a photo or map In order to Identify specific locations In need of mitigation restoration or changed riparian management
httpwaterepagovsci tech dataittoolswarssspla_box08cfm 582014
Bank Erosion Prediction (BEHI NBS) I W ARSSS IUS EPA Page 3 of3
Slrum BEHJ A ectNe
Bank- tlur fhrk Str~$$ M ect~gtoe +Toe Pnl Stahltlo Prelt$cted Erlt)sioo ~ Tee Pin Elfiyen3ioo t Mnsur~d EngtSicent11 f
Date Illite Horiiont~l Venlual Hotu Horhont~l Vertical tfotes
-----
Veulcalllank Pronle Strum OMe
6 -middot- --middot -middotmiddot- ---- -middotmiddotmiddot I
liorirontal Distance tfl)
The oombinatlon of BEHI and NBS risk ratings were used to develop the relations shown In Figure 116 (PDF 303 kb lp) (Colorado data) and in Figure 116 (PDF 507 kb 1p) (Yellowstone National Park data) These
rela~ons indicated a statisUcaly valid way of predicting annual streambank erosion rate in feelyear using BEHI and NBS ratings middot (Rosgen 1996 2001a) This allows the user to predict annual streambank
middot erosion rates to help apportion annual sediment yields to various sources The relations for Colorado (sedimentary and metamorphic) and Yellowstone (volcanism and alpine glaciation) are not intended to be
-universal for alluvium but rather provide a framework for other to develop Figure 115 Cid 10 view similar relations or validate these relations locally The application of these fJQure 116 Clid to view
relations allows the field practitioner to obtain BEHI and NBS ratings along river reaches of varying conditlonlt is imperative to plot these ratings also on a photo or map in order to identify specific locations in need of mitigation restoration or changed riparian management RelUIJllt1 Main Flowchart N0ld to Next Step
hltpwater epa govlscilechldalaitltoolsJwarsssfpla _box08cfm
http water epagovscitech datai ttoolswarsssp Ia_box08cfm 582014
- barcode 557062
- barcodetext SDMS Doc ID 557062
Bank Erosion Prediction (BEHI NBS) IWARSSS IUS EPA Page 2 of3
Figure 114 Common bank angle scenarios
Woruheet 20 Clid(1 ~~-
middotmiddotmiddot-~-middot--middot~middot-middot~~--middot-middotmiddotmiddot - shy
Table 18 Velocity gradient and near-btnk stress Indices ~21ClkOiifWBenk Erosion Velocity Near~bank stressshear
RiskRetinq Gradient stress Very low Less them 05 less than 08
Low 05 -1 0 06- L05 Moderate U-16 106 -114
Hiqh 161 -20 U5-119 VeryHiqh 21-24 12- L6 Extreme Greater than 24 Greater then 160
The Near-Bank Stress (NBS) variables used in the prediction methodology indicate potential disproportionate energy distribution In the near-bank region (113 of channel cross-section associated with the bank being evaluated) Changes in near-bank stress can accelerate streambank erosion The initial criteria for NBS are summarized In Rosgen (1996 2001a) and shown In Table 18 Additional criteria shown in Worksheet 22 below were established to assist in the field determination of NBS for a variety of Inventory levels Use Worksheet 22a PDF 39kb 1 p) to complete an NBS rating using the methods 1-7) appropriate for the available data Use the conversion table in Worksheet 22a to determine and record the final NBS rating for impaired and reference reaches
It Is Imperative to also plot the BE HI and NBS ratings on a photo or map In order to Identify specific locations In need of mitigation restoration or changed riparian management
httpwaterepagovsci tech dataittoolswarssspla_box08cfm 582014
Bank Erosion Prediction (BEHI NBS) I W ARSSS IUS EPA Page 3 of3
Slrum BEHJ A ectNe
Bank- tlur fhrk Str~$$ M ect~gtoe +Toe Pnl Stahltlo Prelt$cted Erlt)sioo ~ Tee Pin Elfiyen3ioo t Mnsur~d EngtSicent11 f
Date Illite Horiiont~l Venlual Hotu Horhont~l Vertical tfotes
-----
Veulcalllank Pronle Strum OMe
6 -middot- --middot -middotmiddot- ---- -middotmiddotmiddot I
liorirontal Distance tfl)
The oombinatlon of BEHI and NBS risk ratings were used to develop the relations shown In Figure 116 (PDF 303 kb lp) (Colorado data) and in Figure 116 (PDF 507 kb 1p) (Yellowstone National Park data) These
rela~ons indicated a statisUcaly valid way of predicting annual streambank erosion rate in feelyear using BEHI and NBS ratings middot (Rosgen 1996 2001a) This allows the user to predict annual streambank
middot erosion rates to help apportion annual sediment yields to various sources The relations for Colorado (sedimentary and metamorphic) and Yellowstone (volcanism and alpine glaciation) are not intended to be
-universal for alluvium but rather provide a framework for other to develop Figure 115 Cid 10 view similar relations or validate these relations locally The application of these fJQure 116 Clid to view
relations allows the field practitioner to obtain BEHI and NBS ratings along river reaches of varying conditlonlt is imperative to plot these ratings also on a photo or map in order to identify specific locations in need of mitigation restoration or changed riparian management RelUIJllt1 Main Flowchart N0ld to Next Step
hltpwater epa govlscilechldalaitltoolsJwarsssfpla _box08cfm
http water epagovscitech datai ttoolswarsssp Ia_box08cfm 582014
- barcode 557062
- barcodetext SDMS Doc ID 557062
Bank Erosion Prediction (BEHI NBS) I W ARSSS IUS EPA Page 3 of3
Slrum BEHJ A ectNe
Bank- tlur fhrk Str~$$ M ect~gtoe +Toe Pnl Stahltlo Prelt$cted Erlt)sioo ~ Tee Pin Elfiyen3ioo t Mnsur~d EngtSicent11 f
Date Illite Horiiont~l Venlual Hotu Horhont~l Vertical tfotes
-----
Veulcalllank Pronle Strum OMe
6 -middot- --middot -middotmiddot- ---- -middotmiddotmiddot I
liorirontal Distance tfl)
The oombinatlon of BEHI and NBS risk ratings were used to develop the relations shown In Figure 116 (PDF 303 kb lp) (Colorado data) and in Figure 116 (PDF 507 kb 1p) (Yellowstone National Park data) These
rela~ons indicated a statisUcaly valid way of predicting annual streambank erosion rate in feelyear using BEHI and NBS ratings middot (Rosgen 1996 2001a) This allows the user to predict annual streambank
middot erosion rates to help apportion annual sediment yields to various sources The relations for Colorado (sedimentary and metamorphic) and Yellowstone (volcanism and alpine glaciation) are not intended to be
-universal for alluvium but rather provide a framework for other to develop Figure 115 Cid 10 view similar relations or validate these relations locally The application of these fJQure 116 Clid to view
relations allows the field practitioner to obtain BEHI and NBS ratings along river reaches of varying conditlonlt is imperative to plot these ratings also on a photo or map in order to identify specific locations in need of mitigation restoration or changed riparian management RelUIJllt1 Main Flowchart N0ld to Next Step
hltpwater epa govlscilechldalaitltoolsJwarsssfpla _box08cfm
http water epagovscitech datai ttoolswarsssp Ia_box08cfm 582014
- barcode 557062
- barcodetext SDMS Doc ID 557062