Design Manual for Roads and Bridges Drainage Design CD 521 Hydraulic design of road edge surface water channels and outlets (formerly HA 37/17, HA 78/96, HA 113/05, HA 119/06) Revision 1 Summary This document gives requirements and guidance for the design of road edge surface water channels and outlets, combined channel and pipe systems for surface water drainage, and grassed surface water channels on motorways and all-purpose trunk roads. Application by Overseeing Organisations Any specific requirements for Overseeing Organisations alternative or supplementary to those given in this document are given in National Application Annexes to this document. Feedback and Enquiries Users of this document are encouraged to raise any enquiries and/or provide feedback on the content and usage of this document to the dedicated Highways England team. The email address for all enquiries and feedback is:
[email protected] This is a controlled document. CD 521 Revision 1 Contents Contents Release notes 4 Foreword 5 Publishing information ................................................ 5 Contractual and legal considerations ........................................ 5 Introduction 6 Background ...................................................... 6 Assumptions made in the preparation of this document ............................. 6 Mutual Recognition .................................................. 6 Abbreviations and symbols 7 Terms and definitions 11 1. Scope 13 Aspects covered ..................................................