INTRODUCTION - ChannelRehabilitation0017SCOPETHE PROCESSTHE GENERALIZED PROCESSFigure 2.1 Generalized Process for Channel Rehabilitation DesignPLANNINGTHE ANALYSIS PROCESSFigure 2.2 The Analysis Process for Channel Rehabilitation DesignSYSTEMS APPROACHFigure 2.3 The Systems ApproachPRELIMINARY DESIGNFigure 2.4 Preliminary Design for Channel RehabilitationPRELIMINARY DESIGN METHODOLOGY - DETERMINATION OF SYSTEM STABILITYPRELIMINARY DESIGN METHODOLOGY - DETERMINATION OF STABLE CHANNEL DIMENSIONSDETERMINE A STABLE CHANNEL MEANDER WAVELENGTH FOR THE PLANFORMSEDIMENT IMPACT ASSESSMENTPRELIMINARY DESIGN SUMMARYFUNDAMENTALS OF FLUVIAL GEOMORPHOLOGY AND CHANNEL PROCESSES - ChannelRehabilitation0035Figure 3.1 The Fluvial System (after Schumm, 1977)The System is Dynamic - ChannelRehabilitation0037Thresholds - ChannelRehabilitation0038LANDFORMS - ChannelRehabilitation0039Figure 3.2 Landforms for a Meandering RiverTable 3.1 Classification of Valley SedimentsChannel Geometry and Cross SectionFigure 3.3 Typical Meandering RiverFigure 3.5 Features Associated With (a) Straight and (b) Meandering RiversPlanform Geometry - ChannelRehabilitation0045Figure 3.6 Typical Plan and Cross Sectional View of Pools and CrossingsFigure 3.7 Typical Middle BarFigure 3.9 Definition Sketch for Channel Geometry (after Leopold et al.,1964)RELATIONSHIPS IN RIVERS - ChannelRehabilitation0049Figure 3.10 Lane's (1957) Relationship Between Channel Patterns, Channel Gradient, and Mean DischargeRELATIONSHIPS IN RIVERS (cont.) - ChannelRehabilitation0051RELATIONSHIPS IN RIVERS (cont.) - ChannelRehabilitation0052CHANNEL CLASSIFICATION - ChannelRehabilitation0053CHANNEL EVOLUTIONTable 3.2 Classification of Alluvial ChannelsFigure 3.12 Channel Classification Based on Pattern and Type of Sediment LoadTable 3.3 Summary of Delineative Criteria for Broad-level ClassificationFigure 3.13 Channel Classification Combining Aspects of SchummCHANNEL EVOLUTION (cont.)Figure 3.14 Incised Channel Evolution Sequence (after Schumm et al., 1984)QUANTIFICATION OF THE EVOLUTIONARY SEQUENCEFigure 3.15 Hickahala Creek Watershed, Slope-drainage Area RelationshipFigure 3.16 Comparison of the Channel Evolution Sequence and the Channel Stability DiagramQUANTIFICATION OF THE EVOLUTIONARY SEQUENCE (cont.)Figure 3.17 Sub-watershed Channels of Hickahala Creek Watershed Plotted on an Ng/Nh DiagramCHANNEL STABILITY CONCEPTS - ChannelRehabilitation0066Figure 3.19 Lane's Balance (after E. W. Lane, from W. Borland)SYSTEM INSTABILITYFigure 3.20 Consequences of System InstabilityFigure 3.20 Consequences of System Instability (cont.)Causes of System Instability - ChannelRehabilitation0071Figure 3.21 Channelized Stream and Abandoned Old ChannelFigure 3.22 Knickpoint in a Degrading ChannelUpstream Factors - ChannelRehabilitation0074Basin Wide Factors - ChannelRehabilitation0075LOCAL INSTABILITY - ChannelRehabilitation0076Overview of Meander Bend ErosionStreambank Erosion and Failure Processes - ChannelRehabilitation0078Figure 3.24 Erosion Generated by Parallel FlowFigure 3.26 Erosion Generated by PipingFigure 3.28 Sheet Erosion with Rilling and GullyingFigure 3.30 Erosion Generated by Vessel ForcesStreambank Erosion and Failure Processes (cont.) - ChannelRehabilitation0083Figure 3.31 Soil FallFigure 3.33 Slab FailureFigure 3.35 Pop-out FailureFigure 3.37 Dry Granular FlowFigure 3.39 Cattle TramplingCLOSING - ChannelRehabilitation0089CLOSING (cont.) - ChannelRehabilitation0090CHANNELIZATION AND CHANNEL MODIFICATION ACTIVITIES AND IMPACTSCHANNELIZATION AND CHANNEL MODIFICATION PROJECT CATEGORIESNAVIGATIONCHANNEL AND BANK INSTABILITYFLOW CONTROL FOR WATER SUPPLYCHANNEL MODIFICATION ACTIVITIES AND ASSOCIATED IMPACTSEnvironmental Effects - ChannelRehabilitation0097CHANNEL ENLARGEMENTRemedial Practices - ChannelRehabilitation0099Operation and Maintenance of Channel Enlargement ProjectsHydraulic Effects - ChannelRehabilitation0101DREDGING AND MININGHydraulic Effects - ChannelRehabilitation0103CONSTRUCTION OF LEVEESHydraulic Effects - ChannelRehabilitation0105Remedial Practices - ChannelRehabilitation0106DIVERSION CHANNELSOperation and Maintenance of Floodway ProjectsEnvironmental Effects - ChannelRehabilitation0109LOW TRAINING STRUCTURES - DIKESHydraulic Effects - ChannelRehabilitation0111GRADE CONTROL - ChannelRehabilitation0112Environmental Effects - ChannelRehabilitation0113Operation and Maintenance of Grade Control StructuresBANK STABILIZATIONOperation and Maintenance of Channel and Bank Stabilization ProjectsCHANNEL RESTORATIONHydraulic Effects - ChannelRehabilitation0118SUMMARY - ChannelRehabilitation0119SUMMARY (cont.)FUNDAMENTALS OF ENGINEERING DESIGNTable 5.1 Suggested Sources of Historical Information (USACE, 1994)GEOGRAPHYTable 5.2 Land Use Classification (after Rundquist, 1975)MEASURED SEDIMENT DATA - RATING CURVE DEVELOPMENTFigure 5.1 Fannegusha Creek Suspended Sediment DischargeTable 5.5 Bed Material Load (Sand Fraction) Relationships at Gaging Sites in the Yazoo Basin, MississippiWATERSHED HYDROLOGYProject Hydrology ConsiderationsFigure 5.3 Cumulative Distribution Function of Discharge for Hotopha Creek, Mean Daily DataWatershed DataFigure 5.4 Flow Duration Relationships for Mean Daily Data on Ten GageWatershed Attributes Geographic Information SystemsWatershed Attributes Geographic Information Systems (cont.)Land UseSoilsWeather and Climatological DataComputation of Project Hydrology - Hydrology ModelsCASC2DFigure 5.6 Conceptual Sketch of CASC2D Overland Flow RoutingMETHODS FOR ASSESSING HISTORICAL RIVER STABILITYFigure 5.7 Definition Sketch of Specific Gage RecordFigure 5.8 Development of Specific Gage RecordFigure 5.9 Specific Gage Record, Indus River Downstream of Sukkar BarrageSpecific Gage AnalysisFigure 5.10 Specific Gage Record Below Trimmu Barrage, IndiaFigure 5.12 Specific Gage Record on Red River at Shreveport, Louisiana and Alexandria, LouisianaSpecific Gage Analysis (cont.)Figure 5.13 Specific Gage Records at Near Bankfull Conditions on the Lower Mississippi RiverFigure 5.14 Specific Gage Record on Mississippi River at Arkansas City, 1940-1974Comparative Thalweg AnalysisFigure 5.16 Comparative Thalweg Profiles for Long Creek, MississippiAerial PhotographyFigure 5.17 Cross Sectional Changes on the Atchafalaya River at Simmesport, LouisianaFigure 5.18 Average Cross Sectional Values for Little Tallahatchie River Below Sardis DamFIELD INVESTIGATION - ChannelRehabilitation0156QUALITATIVE OBSERVATIONSField Identified FeaturesField Identified Features (cont.)CHANNEL, STREAMBED, AND STREAMBANK DESCRIPTIONSCHANNEL, STREAMBED, AND STREAMBANK DESCRIPTIONS (cont.)Figure 5.20 The Stages of Terrace Development Following Two Sequences of Events Leading to the Same Surface GeometryFigure 5.22 Relationship Between Gradient and Bed Forms (after Grant et al., 1990)Figure 5.23 Bar TypesFigure 5.24 Bed Forms (after Simons and Richardson, 1966)Figure 5.25 Headcuts (after Schumm et al., 1984)BANK CHARACTERISTICSBANK CHARACTERISTICS (cont.)COMPUTATIONAL METHODS FOR STABLE CHANNEL DESIGNFigure 5.26 Equilibrium Channel Slope Versus Drainage Area for Hickahala Creek, Batupan Bogue and Hotopha Creek are ShownTable 5.7 Maximum Mean Velocities Safe Against Erosion (Etcheverry, 1915)Table 5.8 Permissible Canal Velocities (Fortier and Scobey, 1926)Figure 5.27 Channel Evaluation Procedural Guide (from USDA, 1977)Figure 5.28a Allowable Velocities for Unprotected Earth Channels (from USDA, 1977)Figure 5.28b (cont.) Allowable Velocities for Unprotected Earth Channels (from USDA, 1977)Tractive Force Design Procedure (Simons, 1957)Figure 5.29 Maximum Unit Tractive Force Versus b/d (from Simons and Sentrk, 1992), b is the Bottom Width and d is the DepthFigure 5.31 Relationship Between Side Slope and K (from Lane, 1953b)Figure 5.32 Variation of Tractive Force With Bed Material d (from Lane, 1953a)Figure 5.33 Angle of Repose of Noncohesive Material (from Lane, 1953b)REGIME THEORY CHANNEL DESIGNTable 5.9 Simons and Albertson (1963) Modified Regime EquationsFigure 5.34 Top Width as Function of Discharge (USACE, 1994)Figure 5.36 Slope as Function of Discharge (USACE, 1994)HYDRAULIC DESIGN PACKAGE FOR CHANNELS (SAM)Sediment Yield CalculationsFigure 5.37 Example of a Sediment Rating CurveFigure 5.39 Example of HydrographFigure 5.40 Froude Number Fn Versus R/D50 CriterionGoverning Equations for Stable Channel Design ProcedureFigure 5.41 Determination of Flow Regimes - Grain Froude Number, Fg, Plotted Against Slope, SFigure 5.42 Viscous Effects on the Transition From LOwer Flow Regime to Upper Flow RegimeGoverning Equations for Stable Channel Design Procedure (cont.) - ChannelRehabilitation0193Governing Equations for Stable Channel Design Procedure (cont.) - ChannelRehabilitation0194Model Application - ChannelRehabilitation0195Figure 5.43 Example of a Stable Channel CurveGRAVEL BED RIVERSFigure 5.44 Velocity Contour Map With Lines Across Which There is No Shear StressGRAVEL BED RIVERS (cont.)Figure 5.45 Threshold of Motion for Granular Material (from Julien, 1995)Figure 5.46 Ratio of Suspended to Total Load Versus Ratio of Shear to Fall VelocitiesModel Application - ChannelRehabilitation0202HEC-6BANK STABILITY - ChannelRehabilitation0204BANK STABILITY (cont.)Figure 5.47a Shear Failure Along a Planar Slip Surface Through the Toe of the SlopeRequired Geotechnical DataSoil Data SourcesTable 5.10 Soil Properties and the Averaging MethodTable 5.11 Soil PropertiesStability of Steep SlopesSELECTION AND DESIGN OF CHANNEL REHABILITATION METHODSSURFACE ARMORStone Armor - ChannelRehabilitation0215Rigid Armor - ChannelRehabilitation0216Flexible MattressDikes and Retards - ChannelRehabilitation0218Other Flow DeflectorsVEGETATIVE METHODS FOR EROSION CONTROLGRADE CONTROL - ChannelRehabilitation0221TYPES OF GRADE CONTROL STRUCTURESFigure 6.1 Channel Stabilization with Rock Sills (adapted from Whitaker and Jaggi, 1986)Structures with Water CutoffFigures 6.2a As Built Riprap Grade Control Structure With Sufficient Launch Stone to Handle Anicipated ScourFigures 6.3a As Built Riprap Grade Control Structure with Impervious Fill Cutoff WallFigures 6.4a As Built Riprap Grade Control Structure with Sheet Pile Cutoff WallFigure 6.5 Sloping Drop Grade Control Structure with Pre-formed Riprap Lined Scour HoleConcrete Drop Structures - ChannelRehabilitation0229Figure 6.6 Bed Stabilizer Design with Sheet Pile Cutoff (U.S. Army Corps of Engineers, 1970)Figure 6.7 ARS-Type Grade Control Structure with Pre-formed Riprap Lined Stilling Basin and Baffle PlateFigure 6.8 Schematic of Modified ARS-Type Grade Control Structure (Abt et al., 1994)Figure 6.9 CIT-Type Drop StructureEFFECTIVENESS OF GRADE CONTROL STRUCTURESFigure 6.10 St. Anthony Falls (SAF) Type Drop Structure (Blaisdell, 1948)Figure 6.11 Riprap Lined Drop Structures (adapted from Tate, 1991)Figure 6.12 Spacing of Grade Control Structure (adapted from Mussetter, 1982)Figure 6.13 Slope Versus Drainage Area RelationshipEFFECTIVENESS OF GRADE CONTROL STRUCTURES (cont.)Figure 6.14 CEM Types in Comparison With a Slope Area CurveFigure 6.15 1995 CEM Data With Two RegressionsFigure 6.16 Relationship between Energy Slope and Computed Sediment Concentration for DEC Monitoring ReachesDownstream Channel Response - ChannelRehabilitation0243Figure 6.17 Sediment Concentration for the 2-Year Discharge Along the GDM No. 54 Slope Area CurveFigure 6.18 Computed Sediment Concentration for CEM TypesDownstream Channel Response (cont.)Table 6.1 Annual Sediment Yield for Monitoring Reaches Surveyed in 1993, 1994, 1995, and 1996Table 6.2 Bank Stability Analysis SummaryFlood Control ImpactsSUMMARY - ChannelRehabilitation0250FLOW CONTROLFigure 6.19 Annual Sediment Load as a Function of Flow Distribution SkewnessFLOW CONTROL (cont.)CLOSING - ChannelRehabilitation0255REFERENCES - ChannelRehabilitation0257REFERENCES (cont.) - ChannelRehabilitation0258REFERENCES (cont.) - ChannelRehabilitation0259REFERENCES (cont.) - ChannelRehabilitation0260REFERENCES (cont.) - ChannelRehabilitation0261REFERENCES (cont.) - ChannelRehabilitation0262REFERENCES (cont.) - ChannelRehabilitation0263REFERENCES (cont.) - ChannelRehabilitation0264REFERENCES (cont.) - ChannelRehabilitation0265REFERENCES (cont.) - ChannelRehabilitation0266REFERENCES (cont.) - ChannelRehabilitation0267REFERENCES (cont.) - ChannelRehabilitation0268REFERENCES (cont.) - ChannelRehabilitation0269REFERENCES (cont.) - ChannelRehabilitation0270REFERENCES (cont.) - ChannelRehabilitation0271REFERENCES (cont.) - ChannelRehabilitation0272REFERENCES (cont.) - ChannelRehabilitation0273REFERENCES (cont.) - ChannelRehabilitation0274REFERENCES (cont.) - ChannelRehabilitation0275APPENDIX A. A PRACTICAL GUIDE TO EFFECTIVE DISCHARGE CALCULATIONINTRODUCTION: THEORIES AND CONCEPTSINTRODUCTION: THEORIES AND CONCEPTS (cont.)HYDROLOGICAL DATA AND CALCULATIONSFigure 1. Derivation of Bed Material Load-discharge Histogram (iii) From Flow Frequency (i) and Bed Material Load Rating Curves (ii)Selection of Discharge Class IntervalTime BaseFigure 2. Downstream Daily Flow Duration Curves for the River Wye, UK Based on Data from Gaging Stations Collected Between 1937 and 1962Regionalized Duration Curve MethodFigure 3. Regionalized Discharge Index for DEC Watersheds, MississippiTable 1 Classification of the Total Sediment LoadFigure 4. Comparison of Sediment Relationships for a Gage Site on Abiaca Creek, MississippiFigure 5 Procedure for Generating a Flow Frequency HistogramFigure 6 Procedure for Generating a Bed Material Load Rating CurveFigure 7 Procedure for Generating a Bed Material Load HistogramStep 1 - Flow Frequency DistributionStep 2 - Bed Material Load Rating CurveStep 3 - Bed Material Load HistogramEVALUATION AND TROUBLESHOOTINGProblems with OutliersEXAMPLE: EFFECTIVE DISCHARGE CALCULATION FOR THE MISSISSIPPI RIVER AT VICKSBURGFigure 9. Flow Duration Curve for Mean Daily Discharge: Lower Mississippi River at Vicksburg, 1950-1982Figure 10 Sand Load Rating Curve: Lower Mississippi River at Vicksburg for 1969-1979Figure 11. Bed Material Load Histogram: Lower Mississippi River at VicksburgFigure 12. Long-channel Variation in Bank Top Elevations: Lower Mississippi in Study ReachTable 2 Regime and Engineered Morphology of the River Blackwater, UKApplication 2: Channel Stability Assessment Using the SAM Hydraulic PackageAPPENDIX I. REFERENCESAPPENDIX I. REFERENCES (cont.) - ChannelRehabilitation0306APPENDIX I. REFERENCES (cont.) - ChannelRehabilitation0307APPENDIX I. REFERENCES (cont.) - ChannelRehabilitation0308APPENDIX I. REFERENCES (cont.) - ChannelRehabilitation0309APPENDIX II. GLOSSARYAPPENDIX II. GLOSSARY (cont.) - ChannelRehabilitation0311APPENDIX II. GLOSSARY (cont.) - ChannelRehabilitation0312ChannelRehabilitation