♦Manual Notice 2019-1
►1. Manual Introduction
- ►1. About this Manual
  - ♦Purpose
  - ♦Conventions and Assumptions
  - ♦Organization
  - ♦Feedback
- ♦2. Introduction to Hydraulic Analysis and Design
▼2. Hydraulic Practices and Governing Law
►3. Processes and Procedures in TxDOT Hydrologic and Hydraulic Activities
►4. Hydrology
- ♦1. Hydrology’s Role in Hydraulic Design
- ►2. Probability of Exceedance
  - ♦Annual Exceedance Probability (AEP)
  - ♦Design AEP
- ►3. Hydrology Policies and Standards
- ♦4. Hydrology Study Requirements
- ►5. Hydrology Study Data Requirements
- ♦6. Design Flood and Check Flood Standards
- ♦7. Selection of the Appropriate Method for Calculating Runoff
- ♦8. Validation of Results from the Chosen Method
- ►9. Statistical Analysis of Stream Gauge Data
- ►10. Regression Equations Method
  - ♦Procedure for Using Omega EM Regression Equations for Natural Basins
- ►11. Time of Concentration
- ►12. Rational Method
  - ♦Assumptions and Limitations
  - ♦Procedure for using the Rational Method
  - ♦Rainfall Intensity
  - ♦Runoff Coefficients
  - ♦Mixed Land Use
- ►13. Hydrograph Method
- ♦14. References
- ►15. Glossary of Hydrology Terms
  - ♦Annual Exceedance Probability (AEP)
  - ♦Annual Flood
  - ♦Annual Flood Series
  - ♦Antecedent Conditions
  - ♦Area-Capacity Curve
  - ♦Attenuation
  - ♦Backwater
  - ♦Bank
  - ♦Bank Storage
  - ♦Bankfull Stage
  - ♦Base Discharge (for peak discharge)
  - ♦Baseflow
  - ♦Basic Hydrologic Data
  - ♦Basic-Stage Flood Series
  - ♦Bifurcation
  - ♦Binomial Statistical Distribution
  - ♦Boundary Condition
  - ♦Calibration
  - ♦Canopy-Interception
  - ♦Channel (watercourse)
  - ♦Channel Storage
  - ♦Computation Duration
  - ♦Computation Interval
  - ♦Concentration Time
  - ♦Confluence
  - ♦Continuous Model
  - ♦Correlation
  - ♦Dendritic
  - ♦Depression Storage
  - ♦Design Flood
  - ♦Design Storm
  - ♦Detention Basin
  - ♦Diffusion
  - ♦Direct Runoff
  - ♦Discharge
  - ♦Discharge Rating Curve
  - ♦Distribution Graph (distribution hydrograph)
  - ♦Diversion
  - ♦Drainage Area
  - ♦Drainage Divide
  - ♦Duration Curve
  - ♦ET
  - ♦Effective Precipitation (rainfall)
  - ♦Evaporation
  - ♦Evaporation Demand
  - ♦Evaporation Pan
  - ♦Evaporation, Total
  - ♦Evapotranspiration
  - ♦Event-Based Model
  - ♦Exceedance Probability
  - ♦Excess Precipitation
  - ♦Excessive Rainfall
  - ♦Falling Limb
  - ♦Field Capacity
  - ♦Field-Moisture Deficiency
  - ♦Flood
  - ♦Flood Crest
  - ♦Flood Event
  - ♦Flood Peak
  - ♦Floodplain
  - ♦Flood Profile
  - ♦Flood Routing
  - ♦Flood Stage
  - ♦Flood Wave
  - ♦Flood, Maximum Probable
  - ♦Flood-Frequency Curve
  - ♦Floodway
  - ♦Flow-Duration Curve
  - ♦Gauging Station
  - ♦Ground Water
  - ♦Groundwater Outflow
  - ♦Groundwater Runoff
  - ♦Hydraulic Radius
  - ♦Hydrograph
  - ♦Hydrologic Budget
  - ♦Hydrologic Cycle
  - ♦Hydrology
  - ♦Hyetograph
  - ♦Index Precipitation
  - ♦Infiltration
  - ♦Infiltration Capacity
  - ♦Infiltration Index
  - ♦Inflection Point
  - ♦Initial Condition
  - ♦Interception
  - ♦Isohyetal Line
  - ♦Lag
  - ♦Lag Time
  - ♦Loss
  - ♦Mass Curve
  - ♦Maximum Probable Flood
  - ♦Meander
  - ♦Model
  - ♦Moisture
  - ♦Objective Function
  - ♦Overland Flow
  - ♦Parameter
  - ♦Parameter Estimation
  - ♦Partial-Duration Flood Series
  - ♦Peak Flow
  - ♦Peak Stage
  - ♦Percolation
  - ♦PMF
  - ♦Precipitation
  - ♦Precipitation, Probable Maximum
  - ♦Probability of Capacity Exceedance
  - ♦Probability of Exceedance
  - ♦Rain
  - ♦Rainfall
  - ♦Rainfall Excess
  - ♦Rating Curve
  - ♦Reach
  - ♦Recession Curve
  - ♦Recurrence Interval (return period)
  - ♦Regulation, Regulated
  - ♦Reservoir
  - ♦Residual-Mass Curve
  - ♦Retention Basin
  - ♦Rising Limb
  - ♦Runoff
  - ♦Saturation Zone
  - ♦NRCS Curve Number
  - ♦Snow
  - ♦Soil Moisture Accounting (SMA)
  - ♦Soil Moisture (soil water)
  - ♦Soil Profile
  - ♦Stage
  - ♦Stage-Capacity Curve
  - ♦Stage-Discharge Curve (rating curve)
  - ♦Stage-Discharge Relation
  - ♦Stemflow
  - ♦Storage
  - ♦Storm
  - ♦Stream
  - ♦Stream Gauging
  - ♦Streamflow
  - ♦Stream-Gauging Station
  - ♦Sublimation
  - ♦Surface Runoff
  - ♦Surface Water
  - ♦Tension Zone
  - ♦Time of Concentration
  - ♦Time of Rise
  - ♦Time to Peak
  - ♦TR-20
  - ♦TR-55
  - ♦Transpiration
  - ♦Underflow
  - ♦Unit Hydrograph
  - ♦Vadose Zone
  - ♦Water Year
  - ♦Watershed
  - ♦WinTR-55
►5. NFIP Design of Floodplain Encroachments & Cross Drainage Structures
►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
  - ♦Roughness Coefficients
  - ♦Energy
  - ♦Steep Slope versus Mild Slope
- ►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 Drainage 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
►8. Culverts
- ►1. Introduction
  - ♦Definition and Purpose
  - ♦Construction
  - ♦Inlets
- ►2. Design Considerations
  - ♦Economics
  - ♦Site Data
  - ♦Culvert Location
  - ♦Waterway Considerations
  - ♦Roadway Data
  - ♦Allowable Headwater
  - ♦Outlet Velocity
  - ♦End Treatments
  - ♦Traffic Safety
  - ♦Culvert Selection
  - ♦Culvert Shapes
  - ♦Multiple Barrel Boxes
  - ♦Design versus Analysis
  - ♦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
- ►5. Velocity Protection and Control Devices
  - ♦Excess Velocity
  - ♦Velocity Protection Devices
  - ♦Velocity Control Devices
  - ♦Broken Back Design and Provisions Procedure
  - ♦Energy Dissipators
- ►6. Special Applications
  - ♦Detour Culverts
  - ♦Risk
  - ♦Engineering Requirements
►9. Bridges
►10. Storm Drains
- ►1. Introduction
  - ♦Overview of Urban Drainage Design
  - ♦Overview of Storm Drain Design
- ►2. Preliminary Concept Development
  - ♦Design Checklist
  - ♦1. Problem Identification
  - ♦2. System Plan
  - ♦3. Design Criteria
  - ♦4. Outfall Considerations and Features
  - ♦5. Utility Conflicts
  - ♦6. Construction
  - ♦7. System Design
  - ♦8. Check Flood
  - ♦9. 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
  - ♦Longitudinal Slopes
  - ♦Transverse (Cross) Slopes
  - ♦Hydroplaning
  - ♦Use of Rough Pavement Texture
- ►5. Storm Drain Inlets
  - ♦Inlet Types
  - ♦Curb Opening Inlets
  - ♦Grate Inlets
  - ♦Linear Drains
  - ♦Slotted Drains
  - ♦Trench Drains
  - ♦Combination Inlets
  - ♦Inlets in Sag Configurations
  - ♦Median/Ditch Drains
  - ♦Drainage Chutes
  - ♦Inlet Locations
- ►6. Gutter and Inlet Equations
- ►7. Conduit Systems
  - ♦Conduits
  - ♦Access Holes (Manholes)
  - ♦Junction Angles
  - ♦Inverted Siphons
  - ♦Conduit Capacity Equations
  - ♦Conduit Design Procedure
  - ♦Conduit Analysis
- ►8. Conduit Systems Energy Losses
►11. Pump Stations
- ►1. Introduction
- ►2. Pump Station Components
  - ♦Overview of Components
- ►3. Pump Station Hydrology
  - ♦Methods for Design
  - ♦Procedure to Determine Mass Inflow
- ►4. Pump Station Hydraulic Design Procedure
  - ♦Introduction
  - ♦Storage Design Guidelines
  - ♦Pump Selection
►12. Reservoirs
- ♦1. Introduction
- ►2. Coordination with Other Agencies
  - ♦Reservoir Agencies
  - ♦TxDOT Coordination
- ►3. Reservoir Analysis Factors
  - ♦Hydrology Methods
  - ♦Flood Storage Potential
  - ♦Reservoir Discharge Facilities
- ►4. Highways Downstream of Dams
  - ♦Peak Discharge
  - ♦Scour Considerations
  - ♦Design Adequacy
- ►5. Highways Upstream of Dams
  - ♦New Location Highways
  - ♦Existing Highways
  - ♦Minimum Top Establishment
  - ♦Structure Location
  - ♦Scour Considerations
- ►6. Embankment Protection
  - ♦Introduction
  - ♦Embankment Protection Location
  - ♦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
►15. Coastal Hydraulic Design
- ►1. Definitions
  - ♦A
  - ♦B
  - ♦C
  - ♦D
  - ♦E
  - ♦F
  - ♦G
  - ♦H
  - ♦I
  - ♦J
  - ♦L
  - ♦M
  - ♦N
  - ♦O
  - ♦P
  - ♦R
  - ♦S
  - ♦T
  - ♦W
- ►2. Introduction and Applicability
  - ♦Purpose
  - ♦Applicable Projects
  - ♦How to Use This Document
  - ♦Level 1, 2, and 3 Analysis Discussion and Examples
  - ♦Chapter Overview
- ►3. Stillwater Levels
- ►4. Waves & Currents
  - ♦Introduction
  - ♦Waves
  - ♦Wave-Generated Currents
- ►5. Design Elevation and Freeboard
- ►6. Erosion
  - ♦Scour
  - ♦Shoreline Change
- ►7. Additional Considerations
- ♦8. References

Chapter 2: Hydraulic Practices and Governing Law

Anchor: #i1006593

Section 1: Overview

This chapter briefly describes the laws and related policies that affect hydraulic design for TxDOT projects. Federal and state regulations and rules have the force of law, and compliance is not at the discretion of TxDOT.

Federal Highway Administration (FHWA) sets forth policy and guidance in the Federal Aid Policy Guide (FAPG). The primary policy for drainage is 23 Code of Federal Regulations (CFR) 650, which is described later in this chapter.