• ♦Manual Notice 2009-1
• ►1. Manual Introduction
  • ►1. About This Manual
    • ♦Non-discrimination
    • ♦Purpose
    • ♦Conventions and Assumptions
    • ♦Organization
    • ♦Feedback
  • ►2. Introduction to Hydraulic Design
    • ♦Description
• ►2. Policy and Guidelines
  • ►1. TxDOT Drainage-Related Policy
    • ♦General Policy
    • ♦FHWA Policy
    • ♦Texas Administrative Code on Drainage
    • ♦Texas Administrative Code on Reservoirs
    • ♦Texas Administrative Code on Irrigation Facilities
  • ►2. Drainage Complaint Guidelines and Procedure
    • ♦Complaints
    • ♦Specific Flood Event Facts
    • ♦Facts Regarding Highway Crossing Involved
  • ►3. Authority over Waters of the United States
    • ♦Introduction
    • ♦Constitutional Power
  • ►4. Required Hydraulic Analysis
    • ♦Function and Scope of Hydraulic Analysis
    • ♦Widening Existing Facilities
  • ►5. FEMA Policy and Procedure
    • ♦National Flood Insurance Program
    • ♦NFIP Maps
    • ♦Flood Insurance Study
    • ♦NFIP Participation Phases
    • ♦Regulated Floodplain Components
    • ♦Projects Requiring Coordination with FEMA
    • ♦Floodway Revisions and NFIP
    • ♦Allowable Floodway Encroachment
    • ♦Replacing Existing Structures
    • ♦Applicability of NFIP Criteria to TxDOT
    • ♦FEMA NFIP Map Revisions
    • ♦Hydrologic Data for FEMA Map Revisions
    • ♦NFIP Map Revision Request Procedure
• ►3. Types of Documentation
  • ►1. Types of Documentation
    • ♦Documentation Categories
  • ►2. Documentation Requirements and Guidelines
    • ♦Documentation Requirements for Existing Locations
    • ♦Documentation Reference Table
    • ♦TxDOT Recommended Guidelines
  • ►3. Documentation Review Stages
    • ♦Review Data
    • ♦Permanent Documentation Retention
• ►4. Data Collection, Evaluation, and Documentation
  • ♦1. Introduction
  • ►2. Site Investigation Data
    • ♦Introduction
    • ♦Drainage Area Characteristics
    • ♦Land Use
    • ♦Stream Course Data
    • ♦Geotechnical Information
    • ♦Adjacent Properties
  • ►3. Other Data Sources
    • ♦Highway Stream Crossing Design Data Sources
    • ♦Streamflow Data
    • ♦Climatological Data
  • ►4. Data Evaluation and Documentation
    • ♦Data Evaluation Procedure
    • ♦Data Documentation Items
    • ♦Other Considerations for Drainage Facilities
• ►5. Hydrology
  • ►1. Introduction
    • ♦Description
    • ♦Peak Discharge versus Frequency Relations
    • ♦Flood Hydrographs
    • ♦Unit Hydrograph
    • ♦Interagency Coordination
  • ►2. Factors Affecting Floods
    • ♦Flood Factors
    • ♦Prediction Information
  • ►3. Design Frequency
    • ♦Concept of Frequency
    • ♦Frequency Determination
    • ♦Design by Frequency Selection
    • ♦Design by Cost Optimization or Risk Assessment
    • ♦Check Flood Frequencies
    • ♦Frequencies of Coincidental Occurrence
    • ♦Rainfall versus Flood Frequency
  • ►4. Hydrologic Method Selection
    • ♦Method Selection
    • ♦Hydrologic Methods
  • ►5. Time of Concentration
    • ♦Description
    • ♦Time of Concentration
    • ♦Procedure to Estimate Time of Concentration
    • ♦Peak Discharge Adjustments
    • ♦Overland Flow Path Selection
  • ►6. The Rational Method
    • ♦Introduction
    • ♦Assumptions of the Rational Method
    • ♦Applicability
    • ♦The Rational Method Equation
    • ♦Rainfall Intensity
    • ♦Runoff Coefficient
    • ♦Rational Procedure
  • ►7. NRCS Runoff Curve Number Methods
    • ♦Introduction
    • ♦NRCS Runoff Curve Aspects
    • ♦Accumulated Rainfall (P)
    • ♦Rainfall Distribution
    • ♦Soil Groups
    • ♦Runoff Curve Number (RCN)
    • ♦Graphical Peak Discharge (TR 55) Procedure
    • ♦NRCS Dimensionless Unit Hydrograph
    • ♦Flood Hydrograph Determination Procedure
    • ♦Complex Watersheds
  • ►8. Design Rainfall Hyetograph Methods
    • ♦Use of the Rainfall Hyetograph
    • ♦Storm Distributions
    • ♦Storm Duration
    • ♦Depth-Duration-Frequency
    • ♦Intensity-Duration-Frequency
    • ♦Standardized Rainfall Hyetograph Development Procedure
    • ♦Standardized Rainfall Hyetograph Example
    • ♦Balanced Storm Method for Developing Hyetographs
  • ►9. Flood Hydrograph Routing Methods
    • ♦Introduction
    • ♦Storage Routing
    • ♦Hydrograph Storage Routing Method Components
    • ♦Storage Indication Routing Method
    • ♦Relationship Determination
    • ♦Storage-Indication Routing Procedure
    • ♦Channel Routing
  • ►10. Statistical Analysis of Stream Gauge Data
    • ♦Stream Gauge Data
    • ♦Log Pearson Type III Distribution and Procedure
    • ♦Skew
    • ♦Accommodating Outliers in the Data
    • ♦Transposition of Data
  • ►11. Regional Regression Methods and Equations
    • ♦Introduction
    • ♦Regression Methods and Equations
    • ♦Regional Regression Equations for Natural Basins
• ►6. Hydraulic Principles
  • ►1. Open Channel Flow
    • ♦Introduction
    • ♦Continuity and Velocity
    • ♦Channel Capacity
    • ♦Conveyance
    • ♦Energy Equations
    • ♦Energy Balance Equation
    • ♦Depth of Flow
    • ♦Froude Number
    • ♦Flow Types
    • ♦Cross Sections
    • ♦Roughness Coefficients
    • ♦Subdividing Cross Sections
    • ♦Importance of Correct Subdivision
  • ►2. Flow in Conduits
    • ♦Open Channel Flow or Pressure Flow
    • ►Depth in Conduits
  • ►3. Hydraulic Grade Line Analysis
    • ♦Introduction
    • ♦Hydraulic Grade Line Considerations
    • ♦Stage versus Discharge Relation
    • ►Conservation of Energy Calculation
• ►7. Channels
  • ►1. Introduction
    • ♦Open Channel Types
    • ♦Methods Used for Depth of Flow Calculations
  • ►2. Stream Channel Planning Considerations and Design Criteria
    • ♦Location Alternative Considerations
    • ♦Phase Planning Assessments
    • ♦Environmental Assessments
    • ♦Consultations with Respective Agencies
    • ♦Stream Channel Criteria
    • ♦Federal Emergency Management Agency (FEMA) Requirements
  • ►3. Roadside Channel Design
    • ♦Roadside Channels
    • ♦Channel Linings
    • ♦Rigid versus Flexible Lining
    • ♦Channel Lining Design Procedure
    • ♦Trial Runs
  • ►4. Stream Stability Issues
    • ♦Stream Geomorphology
    • ♦Stream Classification
    • ♦Modification to Meandering
    • ♦Graded Stream and Poised Stream Modification
    • ♦Modification Guidelines
    • ♦Realignment Evaluation Procedure
    • ♦Response Possibilities and Solutions
    • ♦Environmental Mitigation Measures
    • ♦Countermeasures
    • ♦Altered Stream Sinuosity
    • ♦Stabilization and Bank Protection
    • ♦Revetments
  • ►5. Channel Analysis Guidelines
    • ♦Stage-Discharge Relationship
    • ♦Switchback
  • ►6. Channel Analysis Methods
    • ♦Introduction
    • ♦Slope Conveyance Method
    • ♦Slope Conveyance Procedure
    • ♦Standard Step Backwater Method
    • ♦Standard Step Data Requirements
    • ♦Standard Step Procedure
    • ♦Profile Convergence
    • ♦Example of the Standard Step Method
• ►8. Culverts
  • ►1. Introduction
    • ♦Culvert Design
    • ♦Construction
    • ♦Inlets
  • ►2. Design Considerations
    • ♦Economics
    • ♦Site Data
    • ♦Culvert Location
    • ♦Waterway Data
    • ♦Roadway Data
    • ♦Allowable Headwater
    • ♦Outlet Velocity
    • ♦End Treatments
    • ♦Traffic Safety
    • ♦Culvert Selection
    • ♦Culvert Shapes
    • ♦Multiple Barrel Boxes (or Multiple Boxes)
    • ♦Analysis versus Design
    • ♦Culvert Design Process
    • ♦Design Guidelines and Procedure for Culverts
  • ►3. Hydraulic Operation of Culverts
    • ♦Parameters
    • ♦Headwater under Inlet Control
    • ♦Headwater under Outlet Control
    • ♦Energy Losses through Conduit
    • ♦Free Surface Flow (Type A)
    • ♦Full Flow in Conduit (Type B)
    • ♦Full Flow at Outlet and Free Surface Flow at Inlet (Type BA)
    • ♦Free Surface at Outlet and Full Flow at Inlet (Type AB)
    • ♦Energy Balance at Inlet
    • ♦Slug Flow
    • ♦Determination of Outlet Velocity
    • ♦Depth Estimation Approaches
    • ♦Direct Step Backwater Method
    • ♦Subcritical Flow and Steep Slope
    • ♦Supercritical Flow and Steep Slope
    • ♦Hydraulic Jump in Culverts
    • ♦Sequent Depth
    • ♦Roadway Overtopping
    • ♦Performance Curves
    • ♦Exit Loss Considerations
  • ►4. Improved Inlets
    • ♦Inlet Use
    • ♦Beveled Inlet Edges
    • ♦Flared Entrance Design for Circular Pipe
  • ►5. Velocity Protection and Control Devices
    • ♦Excess Velocity
    • ♦Velocity Protection Devices
    • ♦Velocity Control Devices
    • ♦Broken Back Design and Provisions Procedure
    • ♦Sill Guidelines
    • ♦Energy Dissipators
• ►9. Bridges
  • ►1. Introduction
    • ♦Hydraulically Designed Bridges
  • ►2. Planning and Location Considerations
    • ♦Introduction
    • ♦National Objectives
    • ♦Location Selection and Orientation Guidelines
    • ♦Environmental Considerations
    • ♦Coordination with Other Agencies
    • ♦Surface Water Interests
    • ♦Water Resource Development Projects
    • ♦FEMA Designated Floodplains
    • ♦Stream Characteristics
    • ♦Replacement, Repair, and Rehabilitation
    • ♦Procedure to Check Present Adequacy of Methods Used
  • ►3. Bridge Hydraulic Considerations
    • ♦Bridge/Culvert Determination
    • ♦Highway-Stream Crossing Analysis
    • ♦Flow through Bridges
    • ♦Backwater in Subcritical Flow
    • ♦Allowable Backwater Due to Bridges
    • ♦Flow Distribution
    • ♦Velocity
    • ♦Bridge Scour and Stream Degradation
    • ♦Freeboard
    • ♦Roadway/Bridge Profile
    • ♦Crossing Profile
    • ♦Single versus Multiple Openings
    • ♦Factors Affecting Bridge Length
  • ►4. Hydraulics of Bridge Openings
    • ♦Bridge Modeling Philosophy
    • ♦Flow Zones and Energy Losses
    • ♦Extent of Impact Determination
    • ♦Water Surface Profile Calculations
    • ♦Bridge Flow Class
    • ♦Zone 2 Loss Methods
    • ♦ Standard Step Backwater Method (used for Energy Balance Method computations)
    • ♦Momentum Balance Method
    • ♦WSPRO Contraction Loss Method
    • ♦Pressure Flow Method
    • ♦Empirical Energy Loss Method (HDS 1)
    • ♦Two-dimensional Techniques
    • ♦Roadway/Bridge Overflow Calculations
    • ♦Backwater Calculations for Parallel Bridges
  • ►5. Single and Multiple Opening Designs
    • ♦Introduction
    • ♦Single Opening Design Guidelines
    • ♦Multiple Opening Design Approach
    • ♦Multiple Bridge Design Procedural Flowchart
    • ♦Cumulative Conveyance Curve Construction
    • ♦Bridge Sizing and Energy Grade Levels
    • ♦Freeboard Evaluation
  • ►6. Bridge Scour
    • ♦Introduction
    • ♦Rates of Scour
    • ♦Scour Components
    • ♦Contraction Scour
    • ♦Live Bed Contraction Scour Equation
    • ♦Clear Water Contraction Scour Equation
    • ♦Local Scour
    • ♦Total Scour Envelope
    • ♦Tidal Scour
    • ♦Unconstricted Waterway Assessment Procedure
    • ♦Procedural Adjustments for Constricted Waterways
    • ♦Other Scour Considerations
  • ►7. Flood Damage Prevention
    • ♦Extent of Flood Damage Prevention Measures
    • ♦Pier Foundations
    • ♦Approach Embankments
    • ♦Abutments
    • ♦Guide Banks (Spur Dikes)
    • ♦Bank Stabilization and River Training Devices
    • ♦Minimization of Hydraulic Forces and Debris Impact on the Superstructure
    • ♦Fender Systems
  • ►8. Risk Assessment
    • ♦Introduction
    • ♦Purpose of Risk Assessment
    • ♦Risk Assessment Concepts
    • ♦Annual Risk
    • ♦Risk Assessment Forms
  • ►9. Appurtenances
    • ♦Bridge Railing
    • ♦Deck Drainage
• ►10. Storm Drains
  • ►1. Introduction
    • ♦Overview of Urban Drainage Design
    • ♦Overview of Storm Drain Design
  • ►2. System Planning and Design Considerations
    • ♦Design Checklist
    • ♦Problem Identification
    • ♦Schematic
    • ♦Material and Shape Selection
    • ♦Design Criteria
    • ♦Outfall Considerations and Features
    • ♦Special Outfall Appurtenances
    • ♦Utility Conflicts
    • ♦Construction
    • ♦Identification of Other Drainage Facilities
    • ♦Design Documentation
    • ♦Documentation Requirements
  • ►3. Runoff
    • ♦Hydrologic Considerations for Storm Drain Systems
    • ♦Flow Diversions
    • ♦Detention
    • ♦Determination of Runoff
    • ♦Other Hydrologic Methods
  • ►4. Pavement Drainage
    • ♦Design Objectives
    • ♦Ponding
    • ♦Transverse Slopes
    • ♦Use of Rough Pavement Texture
    • ♦Gutter Flow Design Equations
    • ♦Ponding on Continuous Grades
    • ♦Ponding at Approach to Sag Locations
    • ♦Hydroplaning
    • ♦Vehicle Speed in Relation to Hydroplaning
    • ♦Water Depth in Relation to Hydroplaning
  • ►5. Storm Drain Inlets
    • ♦Inlet Types
    • ♦Curb Opening Inlets
    • ♦Grate Inlets
    • ♦Slotted Drains
    • ♦Combination Inlets
    • ♦Inlets in Sag Configurations
    • ♦Median/Ditch Drains
    • ♦Inlet Locations
    • ♦Ponded Width Options
    • ♦Carryover Design Approach
    • ♦Curb Inlets On-Grade
    • ♦Curb Inlets in Sag Configuration
    • ♦Slotted Drain Inlet Design
    • ♦Grate Inlets On-Grade
    • ♦Bicycle Safety for Grate Inlets On-Grade
    • ♦Design Procedure for Grate Inlets On-Grade
    • ♦Design Procedure for Grate Inlets in Sag Configurations
  • ►6. Conduit Systems
    • ♦Conduits
    • ♦Manholes
    • ♦Inverted Siphons
    • ♦Conduit Capacity Equations
    • ♦Conduit Design Procedure
    • ♦Conduit Analysis
  • ►7. Conduit Systems Energy Losses
    • ♦Minor Energy Loss Attributions
    • ♦Junction Loss Equation
    • ♦Exit Loss Equation
    • ♦Manhole Loss Equations
• ►11. Pump Stations
  • ►1. Introduction
    • ♦Purpose of Pump Stations
    • ♦Security and Access Considerations
    • ♦Safety and Environmental Considerations
  • ►2. Pump Station Components
    • ♦Overview
  • ►3. Pump Station Hydrology
    • ♦Methods for Design
  • ►4. Pump Station Design Procedure
    • ♦Design Guidelines
    • ♦Pump Characteristics
    • ♦Hydraulic Design Procedure
    • ♦Average Pump Capacity Requirements
    • ♦Pump Sizes
• ►12. Reservoirs
  • ►1. Introduction
    • ♦Function of Reservoirs
    • ♦Impact of Reservoirs on Highways
  • ►2. Coordination with Other Agencies
    • ♦Reservoir Agencies
    • ♦TxDOT Coordination
  • ►3. Reservoir Design Factors
    • ♦Hydrology Methods
    • ♦Flood Storage Potential
    • ♦Reservoir Discharge Facilities
  • ►4. Reservoirs Upstream of Highway
    • ♦Peak Discharge
    • ♦Design Adequacy
    • ♦Future Liability
  • ►5. Criteria for Highways Upstream of Dams
    • ♦New Location Highways
    • ♦Adjustments to Existing Highways
    • ♦Minimum Top Establishment
    • ♦Basis for Minimum Embankment Elevation
    • ♦Structure Location
    • ♦Embankment Protection
  • ►6. Embankment Protection
    • ♦Introduction
    • ♦Rock Riprap
    • ♦Soil-Cement Riprap
    • ♦Articulated Riprap
    • ♦Concrete Riprap
    • ♦Vegetation
• ►13. Storm Water Management
  • ►1. Introduction
    • ♦Storm Water Management and Best Management Practices
    • ♦Requirements for Construction Activities
    • ♦Storm Drain Systems Requirements
  • ►2. Soil Erosion Control Considerations
    • ♦Erosion Process
    • ♦Natural Drainage Patterns
    • ♦Stream Crossings
    • ♦Encroachments on Streams
    • ♦Public and Industrial Water Supplies and Watershed Areas
    • ♦Geology and Soils
    • ♦Coordination with Other Agencies
    • ♦Roadway Guidelines
    • ♦Severe Erosion Prevention in Earth Slopes
    • ♦Channel and Chute Design
  • ►3. Inspection and Maintenance of Erosion Control Measures
    • ♦Inspections
    • ♦Embankments and Cut Slopes
    • ♦Channels
    • ♦Repair to Storm Damage
    • ♦Erosion/Scour Problem Documentation
  • ►4. Quantity Management
    • ♦Impacts of Increased Runoff
    • ♦Storm Water Quantity Management Practices
• ►14. Conduit Strength and Durability
  • ►1. Conduit Durability
    • ♦Introduction
    • ♦Service Life
  • ►2. Estimated Service Life
    • ♦Corrugated Metal Pipe and Structural Plate
    • ♦Corrugated Steel Pipe and Steel Structural Plate
    • ♦Exterior Coating
    • ♦Corrugated Aluminum Pipe and Aluminum Structural Plate
    • ♦Post-applied Coatings and Pre-coated Coatings
    • ♦Paving and Lining
    • ♦Reinforced Concrete
    • ♦Plastic Pipe
  • ►3. Installation Conditions
    • ♦Introduction
    • ♦Trench
    • ♦Positive Projecting (Embankment)
    • ♦Negative Projecting (Embankment)
    • ♦Imperfect Trench
    • ♦Bedding for Pipe Conduits
  • ►4. Structural Characteristics
    • ♦Introduction
    • ♦Corrugated Metal Pipe Strength
    • ♦Concrete Pipe Strength
    • ♦High Strength Reinforced Concrete Pipe
    • ♦Recommended RCP Strength Specifications
    • ♦Strength for Jacked Pipe
    • ♦Reinforced Concrete Box
    • ♦Plastic Pipe

Hydraulic Design Manual

March 2009

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