Riprap Design and Construction Guide Public Safety Section Water Management Branch Province of British Columbia Ministry of Environment, Lands and Parks March 2000 Riprap Design and Construction Guide Public Safety Section Water Management Branch Province of British Columbia Ministry of Environment, Lands and Parks March 2000 Canadian Cataloguing in Publication Data Main entry under title: Riprap design and construction guide Includes bibliographical references: p 19 ISBN 0-7726-4185-4 1. Dikes (Engineering) – British Columbia – Design and Construction. 2. Dikes (Engineering) – Law and legislation – British Columbia. 3. Riprap - British Columbia. 1. Northwest Hydraulic Consultants Ltd. II. British Columbia. Water Management Branch. TC337.R56 2000 627.42 C00-960103-1 Table of Contents 1. General.................................................................................................................................................1 1.1 Bank Protection in British Columbia.......................................................................................1 2. Legislation and Regulatory Controls ................................................................................................2 2.1 Water Act.................................................................................................................................2 2.2 Dike Maintenance Act .............................................................................................................2 2.3 Canada Fisheries Act ...............................................................................................................2 2.4 Land Act..................................................................................................................................2 2.5 Canada Navigable Waters Protection Act................................................................................2 3. Considerations for Design and Construction ...................................................................................3 3.1 Failure of Riprap Revetments..................................................................................................3 3.1 Typical Bank Protection Problems ..........................................................................................3 3.3 Limitations of the Guide..........................................................................................................3 4. Rip Rap Design....................................................................................................................................4 4.1 Characteristics Requiring Design ............................................................................................5 4.2 Background to Design .............................................................................................................5 4.3 Scour Depth.............................................................................................................................5 4.4 Alignment of Revetments ........................................................................................................6 4.5 End Treatments and Top Treatments of Revetments...............................................................6 4.6 Riprap Dimensions ..................................................................................................................6 4.6.1 The Size of Riprap .................................................................................................................................................... 6 4.6.2 Rock Shape ............................................................................................................................................................... 7 4.6.3 Rock Density............................................................................................................................................................. 7 4.7 Determining the Required Rock Size ......................................................................................7 4.8 Riprap Gradation.....................................................................................................................7 4.9 Thickness .................................................................................................................................8 4.10 Bank Slope and the Vertical Extent of Protection ...................................................................8 4.11 Toe Treatment or Protection Against Scour ............................................................................8 4.12 Riprap Filters ...........................................................................................................................9 4.13 Ice, Debris, and Other Considerations.....................................................................................9 5. Riprap Revetment Construction Practices .....................................................................................10 5.1 Approvals and Instream Construction Windows ...................................................................10 5.2 Environmental Management Program ...................................................................................10 5.3 Site Preparation......................................................................................................................10 5.4 Placing Filter Layers..............................................................................................................10 5.5 Quality ...................................................................................................................................10 5.6 Gradation ...............................................................................................................................11 5.7 Rock Riprap Construction .....................................................................................................11 Riprap Design and Construction Guide 6. Environmental Design and Mitigation............................................................................................12 6.1 General...................................................................................................................................12 6.2 Examples of Modifications to Riprap Revetments for Mitigation.........................................12 7. Emergency Construction or Repair Practices................................................................................13 7.1 General...................................................................................................................................13 7.2 Emergency Repair of Revetment Washouts ..........................................................................13 8 Maintenance ......................................................................................................................................15 8.1 General...................................................................................................................................15 8.2 High water patrols..................................................................................................................15 8.3 Post-Flood Inspections...........................................................................................................15 8.4 Minor repair...........................................................................................................................15 8.5 Riprap Stockpiling.................................................................................................................16 8.6 Management of Vegetation....................................................................................................16 9. References..........................................................................................................................................17 BC Ministry of Environment, Lands & Parks 1. General The purpose of this guide is to assist Diking velocities are very common. Adequate toe Authorities, Local Authorities, and other protection is vital to the stability of the agencies in the design and construction of slope revetment. In extreme circumstances, grouting or bank protection works and to provide current of the riprap may be required to provide information on the design and construction of adequate resistance to movement. riprap in British Columbia for use by owners and design professionals. The guide addresses Riprap is the most commonly used bank design and construction of repairs to existing protection material in British Columbia. In works, design and construction of new works, some cases and also in some other jurisdictions, and construction of emergency works. revetments are constructed of concrete blocks, gabions, concrete bags or mattresses, jacks or The guide is a summary of the technical report similar structures, articulated concrete slabs, included as Appendix A. The technical report rigid pavements, timber piles or fences, bio- provides details for the design and construction engineering, or woody debris, such as trees, root of riprap revetments. boles, or brush. Design of blanket revetments with these other, less common, materials is not 1.1 Bank Protection in British considered in this guide. Columbia The advantages of riprap are that it is highly This guide addresses the design and construction durable, has a history of use, and is available in of protective works to prevent erosion of river most of British Columbia. Structures built from banks and dike slopes from stream flow. The riprap are flexible, do not fail under minor