1. Manual Introduction | Hydraulic Design Manual | TxDOT Manual System

♦Manual Notice 2004-1
▼1. Manual Introduction
- ►1. About This Manual
  - ♦Purpose
  - ♦Conventions and Assumptions
  - ♦Organization
  - ♦Feedback
- ►2. Introduction to Hydraulic Design
  - ♦Description
►2. Policy and Guidelines
►3. Types of Documentation
►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
- ►4. Data Evaluation and Documentation
►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
- ►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
- ►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
►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
►7. Channels
- ►1. Introduction
  - ♦Open Channel Types
  - ♦Methods Used for Depth of Flow Calculations
- ►2. Stream Channel Planning Considerations and Design Criteria
- ►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
- ►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
- ►5. Single and Multiple Opening Designs
- ►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
- ►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
- ►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
►14. Conduit Strength and Durability
- ►1. Conduit Durability
  - ♦Introduction
  - ♦Service Life
- ►2. Estimated Service Life
- ►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

Chapter 1: Manual Introduction

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Section 1: About This Manual

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Purpose

Hydraulic facilities include open channels, bridges, culverts, storm drains, pump stations, and storm-water quantity and quality control systems. Each can be part of a larger facility that drains water. In analyzing or designing drainage facilities, your investment of time, expense, concentration, and task completeness should be influenced by the relative importance of the facility. This manual provides procedures recommended by the Texas Department of Transportation (TxDOT) for analyzing and designing effective highway drainage facilities.

Anchor: #i999036Manual Revision History
Version	Publication Date	Summary of Changes
2001-1	October 2001	New manual; replaced 1985 Bridge Division Hydraulic Manual.
2002-1	April 2002	Revision adding English measurement units, deleting unnecessary section on wave runup analysis, streamlining organization, and correcting minor errors.
2002-2	November 2002	Revision updating equations in Chapters 4, 5, and 8; providing new equations on pavement drainage ponding and curb inlets in sag configurations; updating the procedure for on-grade slotted drain inlets, and correcting minor errors.

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Conventions and Assumptions

This manual provides information, where possible, in both English standard measurement units and in metric measurement units.

This manual assumes that hydraulic designers have access to programmable calculators, computer spreadsheets, and specific hydraulic computer programs.