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Cover of Guide to Road Design Part 5A: Drainage: Road Surface, Networks, Basins and Subsurface
Guide to Road Design Part 5A: Drainage: Road Surface, Networks, Basins and Subsurface
  • Publication no: AGRD05A-24
  • ISBN: 978-1-922994-61-5
  • Published: 23 December 2024
  • Edition: 2.2

Guide to Road Design Part 5A: Drainage: Road Surface, Networks, Basins and Subsurface, provides road designers and other practitioners with guidance on the design of the collection and discharge of water from road surfaces, pit and pipe systems, basins and subsurface drains.

This Guide needs to be used in conjunction with the other two Parts of the Guide to Road Design that relate to drainage design:

  • Guide to Road Design Part 5: Drainage – General and Hydrology Considerations
  • Guide to Road Design Part 5B: Drainage – Open Channels, Culverts and Floodway Crossings.

This Guide contains information on major/minor drainage systems, and the collection and discharge of road surface flows to support the operation and management of the road network. Guidance is provided on aquaplaning, and the design of drainage inlets and pipe networks receiving the flows. The principles of retention and detention basins and their design are also outlined.

In Edition 2.1 references have been updated throughout.

Edition  2.2 makes a minor correction to Table 5.1 Allowable spread widths and gutter flows.

In Edition 2.1 references have been updated throughout.

  • Summary
  • 1. Introduction
    • 1.1 Purpose
    • 1.2 Scope of this Part
    • 1.3 Road Safety
  • 2. Major/Minor Drainage Concept
    • 2.1 General
    • 2.2 Minor System
    • 2.3 Major System
    • 2.4 Regional Approach
    • 2.5 Design Considerations
    • 2.6 Planning of Major Urban Systems
      • 2.6.1 Isolated and Non-isolated (Connectivity of) Catchments
      • 2.6.2 Major Urban Drainage Design Concepts
      • 2.6.3 Major Urban System Planning Procedure
      • 2.6.4 Design Recurrence Interval
    • 2.7 Worked Examples – Major/Minor Drainage System
      • 2.7.1 Example 1: Estimation of Gap Flow
      • 2.7.2 Example 2: Major Drainage System Design
  • 3. Road Surface Drainage
    • 3.1 General
    • 3.2 Road Surface Flow
    • 3.3 Capture, Movement and Disposal of Surface Flows
      • 3.3.1 Concentration and Capture of Surface Water
      • 3.3.2 Movement of Captured Water
      • 3.3.3 Water Disposal
    • 3.4 Road Pavement and Subsurface Drainage
  • 4. Aquaplaning
    • 4.1 What is Aquaplaning?
    • 4.2 Aquaplaning vs Skidding
    • 4.3 Assessment Process
    • 4.4 Causal Factors
    • 4.5 Road Surfacing
      • 4.5.1 Pavement Surface Types
    • 4.6 Tyres
    • 4.7 The Road-tyre Interface
    • 4.8 Skid Resistance
    • 4.9 Assessment – Water Film Depth
      • 4.9.1 Adopted Method
      • 4.9.2 Basis/Limits
      • 4.9.3 Texture Depth
      • 4.9.4 Drainage Path
      • 4.9.5 Rainfall Intensity
    • 4.10 Assessment – Aquaplaning Potential
      • 4.10.1 Assessment Criteria
      • 4.10.2 Basis/Limits
    • 4.11 Quick Assessment
    • 4.12 Puddles/Wheel Ruts
    • 4.13 Guidance to Reduce Aquaplaning Potential
    • 4.14 Worked Example 1 – Aquaplaning
  • 5. Kerbed Drainage
    • 5.1 Introduction
      • 5.1.1 Scope
    • 5.2 Design Considerations
      • 5.2.1 General
      • 5.2.2 Drainage Inlet Types
      • 5.2.3 Existing Drainage Infrastructure
      • 5.2.4 Location of Other Infrastructure
      • 5.2.5 Bridges and Other Structures
      • 5.2.6 Non-motorised Road Users
      • 5.2.7 Materials
      • 5.2.8 Structural Considerations
      • 5.2.9 Safety Considerations
      • 5.2.10 Design Criteria
      • 5.2.11 Computer Programs
    • 5.3 Kerbed Drainage Elements
      • 5.3.1 Kerbing
      • 5.3.2 Inlets
      • 5.3.3 Inlet Capacity
      • 5.3.4 Inlet Locations
    • 5.4 Design Criteria
      • 5.4.1 General
      • 5.4.2 Pavement Spread and Gutter Flow Limits
      • 5.4.3 Spacing
      • 5.4.4 Size
      • 5.4.5 Gradient
    • 5.5 Design Theory
      • 5.5.1 Gutter Flow
      • 5.5.2 Inlet Capture Rates
      • 5.5.3 Blockage
    • 5.6 Design Procedure
      • 5.6.1 Data Collection
      • 5.6.2 Site Investigation
      • 5.6.3 Identify Drainage Outfalls
      • 5.6.4 Establish Design Criteria
      • 5.6.5 Select Inlet Type
      • 5.6.6 Placement of Trial Inlets
      • 5.6.7 Define Sub-catchments
      • 5.6.8 Calculate Run-off Coefficients
      • 5.6.9 Calculate Time of Concentration
      • 5.6.10 Establish Design Rainfall Intensity
      • 5.6.11 Calculate Design Flows
      • 5.6.12 Spread Compliance Check
      • 5.6.13 Establish Inlet Capture Flows
      • 5.6.14 Design of Underground Piped Network
      • 5.6.15 Major Event Check
      • 5.6.16 Design Documentation
    • 5.7 Worked Example – Kerbed Drainage
      • 5.7.1 Example 1: Gutter Flow
      • 5.7.2 Example 2: Pit Spacing
  • 6. Underground Piped Networks
    • 6.1 Introduction
    • 6.2 Design Considerations
      • 6.2.1 General
      • 6.2.2 Drainage Outfalls
      • 6.2.3 Access Chamber Location
      • 6.2.4 Existing Drainage Infrastructure
      • 6.2.5 Location of Other Infrastructure
      • 6.2.6 Bridge Decks
      • 6.2.7 Structural Considerations
      • 6.2.8 Road User Considerations
    • 6.3 Piped Network Elements
      • 6.3.1 Access Chambers
      • 6.3.2 Pipes
      • 6.3.3 Materials
    • 6.4 Structural Requirements
      • 6.4.1 Pipes
      • 6.4.2 Joint Types
      • 6.4.3 Bedding and Haunch Support
    • 6.5 Design Criteria
      • 6.5.1 General
      • 6.5.2 Size
      • 6.5.3 Depth of Installation/Minimum Cover
      • 6.5.4 Pipe Velocities and Grades
      • 6.5.5 Clearances
    • 6.6 Design Theory
      • 6.6.1 Hydraulic Calculations – General
      • 6.6.2 Hydraulic Grade Line and Total Energy Line
      • 6.6.3 Starting HGL (Tailwater)
      • 6.6.4 Losses – General
      • 6.6.5 Friction Losses
      • 6.6.6 Losses at Pipe Bends
      • 6.6.7 Exit Losses
      • 6.6.8 Pit Losses
      • 6.6.9 Drop Through Pits
      • 6.6.10 Drop Pits
      • 6.6.11 Pipe Sizing
      • 6.6.12 Reduction in Pipe Size
      • 6.6.13 Special Design Case
    • 6.7 Design Procedure
      • 6.7.1 Data Collection
      • 6.7.2 Site Investigation
      • 6.7.3 Computer Software
      • 6.7.4 Design Process
      • 6.7.5 Design Flow Chart
    • 6.8 Construction and Maintenance
    • 6.9 Worked Example – Pipes Network
      • 6.9.1 Example 1: Pipeline Design (Hydraulic Gradeline Design)
  • 7. Basins
    • 7.1 Introduction
      • 7.1.1 Scope
      • 7.1.2 Types of Basins
      • 7.1.3 Characteristics of Basins
      • 7.1.4 Basin Construction
    • 7.2 Detention Basins
      • 7.2.1 General
      • 7.2.2 Types of Detention Basins
      • 7.2.3 Advantages and Disadvantages of Detention Basins
      • 7.2.4 Design Principles – Detention Basins
      • 7.2.5 Design Principles – On-site Detention
      • 7.2.6 Design Procedure for a Detention Basin
      • 7.2.7 Initial Design and Feasibility
      • 7.2.8 Simple Hydrologic Method of Routing
      • 7.2.9 Other Design Considerations
    • 7.3 Extended Detention Basin
      • 7.3.1 Description
      • 7.3.2 Design Guidelines
    • 7.4 Retention Basins
      • 7.4.1 Purpose
      • 7.4.2 Information Required
      • 7.4.3 Location
      • 7.4.4 Layout
      • 7.4.5 Design Criteria
    • 7.5 Worked Example – Basin
      • 7.5.1 Example: Calculating Basin Size
  • 8. Subsurface Drainage
    • 8.1 Purpose of Subsurface Drainage
    • 8.2 Other Relevant Austroads Guides
    • 8.3 Sources of Moisture
    • 8.4 Control of Road Moisture
    • 8.5 Types of Subsurface Drains
    • 8.6 Locations of Subsurface Drains
      • 8.6.1 Longitudinal Subsurface Drains
      • 8.6.2 Transverse Subsurface Drains
      • 8.6.3 Cut-off (Formation) Drains
      • 8.6.4 Combined Stormwater and Groundwater Drains
      • 8.6.5 Locations of Subsurface Drains on Rural Roads
      • 8.6.6 Access to Subsurface Drains
    • 8.7 Drainage Details
      • 8.7.1 Size of Drain
      • 8.7.2 Materials
      • 8.7.3 Filters
      • 8.7.4 Minimum Diameter
      • 8.7.5 Minimum Cover
      • 8.7.6 Minimum Grades
      • 8.7.7 Sub-pavement Layers
    • 8.8 Design Procedures
      • 8.8.1 Data Required
      • 8.8.2 Procedure
    • 8.9 Specialist Subsurface Drainage Techniques
      • 8.9.1 Lowering of Groundwater Table
      • 8.9.2 Schilfgaarde’s Method
      • 8.9.3 Draining an Inclined Aquifer
      • 8.9.4 Design of a Drainage Blanket to Lower a Water Table
      • 8.9.5 Design of Cut-off (Formation) Drains
      • 8.9.6 Capillary Rise in Soils
    • 8.10 Worked Examples – Subsurface
  • References
  • Appendix A Pit Performance Curves Used in Victoria
    • A.1 Side Entry Pits – 1 Metre Inlet
    • A.2 Side Entry Pits – 1.5 Metre Inlet
  • Appendix B Discharge-Velocity Curves
    • B.1 Circular Pipes (Manning’s Equation)
    • B.2 Circular Pipes (Colebrook-White)
    • B.3 Circular Pipes – Part Full
    • B.4 Box Culvert (Colebrook-White)
  • Appendix C Example Pipe Chart for Minimum Pipe Cover for Various Compactors
Related publications
Guide to Road Design Part 5: Drainage-General and Hydrology Considerations
AGRD05-23
Guide to Road Design Part 5B: Drainage-Open Channels, Culverts and Floodway Crossings
AGRD05B-23
View all related publications
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