W201-18

National Standard of Canada

Construction of bioretention systems

Legal Notice for Standards

Canadian Standards Association (operating as “CSA Group”) develops standards through a consensus standards development process approved by the Standards Council of Canada. This process brings together volunteers representing varied viewpoints and interests to achieve consensus and develop a standard. Although CSA Group administers the process and establishes rules to promote fairness in achieving consensus, it does not independently test, evaluate, or verify the content of standards.

Disclaimer and exclusion of liability

This document is provided without any representations, warranties, or conditions of any kind, express or implied, including, without limitation, implied warranties or conditions concerning this document’s fitness for a particular purpose or use, its merchantability, or its non-infringement of any third party’s intellectual property rights. CSA Group does not warrant the accuracy, completeness, or currency of any of the information published in this document. CSA Group makes no representations or warranties regarding this document’s compliance with any applicable statute, rule, or regulation.

IN NO EVENT SHALL CSA GROUP, ITS VOLUNTEERS, MEMBERS, SUBSIDIARIES, OR AFFILIATED COMPANIES, OR THEIR EMPLOYEES, DIRECTORS, OR OFFICERS, BE LIABLE FOR ANY DIRECT, INDIRECT, OR INCIDENTAL DAMAGES, INJURY, LOSS, COSTS, OR EXPENSES, HOWSOEVER CAUSED, INCLUDING BUT NOT LIMITED TO SPECIAL OR CONSEQUENTIAL DAMAGES, LOST REVENUE, BUSINESS INTERRUPTION, LOST OR DAMAGED DATA, OR ANY OTHER COMMERCIAL OR ECONOMIC LOSS, WHETHER BASED IN CONTRACT, TORT (INCLUDING NEGLIGENCE), OR ANY OTHER THEORY OF LIABILITY, ARISING OUT OF OR RESULTING FROM ACCESS TO OR POSSESSION OR USE OF THIS DOCUMENT, EVEN IF CSA GROUP HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES, INJURY, LOSS, COSTS, OR EXPENSES.

In publishing and making this document available, CSA Group is not undertaking to render professional or other services for or on behalf of any person or entity or to perform any duty owed by any person or entity to another person or entity. The information in this document is directed to those who have the appropriate degree of experience to use and apply its contents, and CSA Group accepts no responsibility whatsoever arising in any way from any and all use of or reliance on the information contained in this document.

CSA Group is a private not-for-profit company that publishes voluntary standards and related documents. CSA Group has no power, nor does it undertake, to enforce compliance with the contents of the standards or other documents it publishes.

Intellectual property rights and ownership

As between CSA Group and the users of this document (whether it be in printed or electronic form), CSA Group is the owner, or the authorized licensee, of all works contained herein that are protected by copyright, all trade-marks (except as otherwise noted to the contrary), and all inventions and trade secrets that may be contained in this document, whether or not such inventions and trade secrets are protected by patents and applications for patents. Without limitation, the unauthorized use, modification, copying, or disclosure of this document may violate laws that protect CSA Group’s and/or others’ intellectual property and may give rise to a right in CSA Group and/or others to seek legal redress for such use, modification, copying, or disclosure. To the extent permitted by licence or by law, CSA Group reserves all intellectual property rights in this document.

Patent rights

Attention is drawn to the possibility that some of the elements of this standard may be the subject of patent rights. CSA Group shall not be held responsible for identifying any or all such patent rights. Users of this standard are expressly advised that determination of the validity of any such patent rights is entirely their own responsibility.

Authorized use of this document

This document is being provided by CSA Group for informational and non-commercial use only. The user of this document is authorized to do only the following:

If this document is in electronic form:

• load this document onto a computer for the sole purpose of reviewing it;

• search and browse this document; and

• print this document if it is in PDF format.

  Limited copies of this document in print or paper form may be distributed only to persons who are authorized by CSA Group to have such copies, and only if this Legal Notice appears on each such copy.

  In addition, users may not and may not permit others to

• alter this document in any way or remove this Legal Notice from the attached standard;

• sell this document without authorization from CSA Group; or

• make an electronic copy of this document.

  If you do not agree with any of the terms and conditions contained in this Legal Notice, you may not load or use this document or make any copies of the contents hereof, and if you do make such copies, you are required to destroy them immediately. Use of this document constitutes your acceptance of the terms and conditions of this Legal Notice.

  
  

  
  

  Standards Update Service

  W201-18

  October 2018

  
  

  Title: Construction of bioretention systems

  To register for e-mail notification about any updates to this publication

• go to store.csagroup.org

• click on CSA Update Service

The List ID that you will need to register for updates to this publication is 2426161.

If you require assistance, please e-mail techsupport@csagroup.org or call 416-747-2233.

Visit CSA Group’s policy on privacy at www.csagroup.org/legal to find out how we protect your personal information.

Canadian Standards Association (operating as “CSA Group”), under whose auspices this National Standard has been produced, was chartered in 1919 and accredited by the Standards Council of Canada to the National Standards system in 1973. It is a not-for- profit, nonstatutory, voluntary membership association engaged in standards development and certification activities.

CSA Group standards reflect a national consensus of producers and users — including manufacturers, consumers, retailers, unions and professional organizations, and governmental agencies. The standards are used widely by industry and commerce and often adopted by municipal, provincial, and federal governments in their regulations, particularly in the fields of health, safety, building and construction, and the environment.

Individuals, companies, and associations across Canada indicate their support for CSA Group’s standards development by

volunteering their time and skills to Committee work and supporting CSA Group’s objectives through sustaining memberships. The more than 7000 committee volunteers and the 2000 sustaining memberships together form CSA Group’s total membership from which its Directors are chosen. Sustaining memberships represent a major source of income for CSA Group’s standards development activities.

CSA Group offers certification and testing services in support of and as an extension to its standards development activities. To ensure the integrity of its certification process, CSA Group regularly and continually audits and inspects products that bear the

CSA Group Mark.

In addition to its head office and laboratory complex in Toronto, CSA Group has regional branch offices in major centres across Canada and inspection and testing agencies in eight countries. Since 1919, CSA Group has developed the necessary expertise to meet its corporate mission: CSA Group is an independent service

organization whose mission is to provide an open and effective forum for activities facilitating the exchange of goods and services through the use of standards, certification and related services to meet national and international needs.

For further information on CSA Group services, write to CSA Group

178 Rexdale Boulevard Toronto, Ontario, M9W 1R3 Canada

A National Standard of Canada is a standard developed by a Standards Council of Canada (SCC) accredited Standards Development Organization, in compliance with requirements and guidance set out by SCC. More information on National Standards of Canada can be found at www.scc.ca.

SCC is a Crown corporation within the portfolio of Innovation, Science and Economic Development (ISED) Canada. With the goal of enhancing Canada's economic competitiveness and social well- being, SCC leads and facilitates the development and use of national and international standards. SCC also coordinates Canadian participation in standards development, and identifies strategies to advance Canadian standardization efforts.

Accreditation services are provided by SCC to various customers, including product certifiers, testing laboratories, and standards development organizations. A list of SCC programs and accredited bodies is publicly available at www.scc.ca.

Standards Council of Canada 600-55 Metcalfe Street Ottawa, Ontario, K1P 6L5 Canada

Cette Norme Nationale du Canada est disponible en versions française et anglaise.

Although the intended primary application of this Standard is stated in its Scope, it is important to note that it remains the responsibility of the users to judge its suitability for their particular purpose.

®A trademark of the Canadian Standards Association, operating as “CSA Group”

National Standard of Canada

W201-18

Construction of bioretention systems

®A trademark of the Canadian Standards Association, operating as “CSA Group”

Published in October 2018 by CSA Group A not-for-profit private sector organization

178 Rexdale Boulevard, Toronto, Ontario, Canada M9W 1R3

To purchase standards and related publications, visit our Online Store at store.csagroup.org

or call toll-free 1-800-463-6727 or 416-747-4044.

ICS 93.010

ISBN 978-1-4883-1412-4

© 2018 Canadian Standards Association

All rights reserved. No part of this publication may be reproduced in any form whatsoever without the prior permission of the publisher.

W201-18 Construction of bioretention systems

Contents

Technical Committee on Green Infrastructure for Stormwater Management 4

Subcommittee on Construction of Bioretention Systems 7

Preface 8

0 Introduction 9

1. Scope 9

   
   

2. Reference publications 10

   
   

3. Definitions and abbreviations 11

   1. Definitions 11

   2. Abbreviations 14

      
      

4. Roles and responsibilities 14

   1. General 14

   2. Basic awareness of potential impacts of changing weather patterns 14

   3. Contractor 15

   4. Engineer 15

   5. Inspector 15

   6. Erosion and sediment control (ESC) professional 15

   7. Landscape practitioner 15

   8. Project manager 15

   9. Bioretention media supplier 16

1. Construction considerations 17

   1. General 17

   2. General considerations 17

   3. Construction supervision 17

      1. General 17

      2. Site visit logs 17

      3. Inspection documentation 17

   4. Utilities 18

      1. Contractor responsibility 18

      2. Utility conflict avoidance 18

         
         

2. Construction sequencing 18

   
   

3. Erosion and sediment control 19

   1. General 19

      
      

      October 2018 © 2018 Canadian Standards Association 1

      W201-18 Construction of bioretention systems

      
      

   2. Erosion and sediment control measures 19

      1. Hierarchical strategy 19

      2. Planning for major and minor storm event 19

      3. Specific erosion and sediment control measures 20

      4. Approaches for erosion and sediment control 20

      5. Types of erosion and sediment control measures 21

   3. Erosion and sediment control plan 22

      1. Implementation 22

      2. Minimum components 22

         
         

4. Documentation responsibilities 23

   1. General 23

   2. Project manager responsibilities 24

      1. General responsibilities 24

      2. Documents provided 24

   3. Contractor’s documentation responsibilities 24

      
      

5. Material supply and material handling 24

   1. General 24

   2. Bioretention media 24

      1. General requirements 24

      2. Bioretention media mixing 24

      3. Bioretention media additives 25

      4. Bioretention media testing 25

      5. Timing of testing of bioretention media 25

      6. Bioretention media composition 27

   3. Plant materials 27

      1. Sourcing of plant stock 27

      2. Timing of seeding and planting 27

      3. Transportation and storage of plant stock 27

   4. Geotextiles 27

   5. Aggregates 27

      
      

6. Installation considerations 28

   1. Avoidance of compaction 28

   2. Alleviation of smearing 28

   3. Alleviation of compaction 28

   4. Grades and grading 28

   5. Geotextiles 28

      1. Placement and approval 28

      2. Installation 28

      3. Seam overlap 28

   6. Liners 29

      1. Impermeable liners 29

      2. Protection of liners 29

   7. Underdrains, valves and piping 29

   8. Monitoring wells 29

   9. Aggregates 29

   10. Inlets, outlets, and overflows 29

       
       

       October 2018 © 2018 Canadian Standards Association 2

       W201-18 Construction of bioretention systems

       
       

   11. Bioretention media 29

       1. Preparation of subgrade 29

       2. Bioretention media installation 30

          
          

7. Landscape considerations 30

   1. Planting 30

      1. General 30

      2. Bioretention planting considerations 30

   2. Watering requirements 31

   3. Seeding 31

      1. Seeding dates 31

      2. Approvals 31

      3. Erosion protection for plant material 31

   4. Cover layer 31

   5. Covering layer installation 31

      
      

8. Construction warranty maintenance 31

   
   

9. Assumption protocols 32

Annex A (informative) — Inspection checklist 33

October 2018 © 2018 Canadian Standards Association 3

W201-18 Construction of bioretention systems

Preface

This is the first edition of CSA W201, Construction of bioretention systems.

It should be noted that this Standard, by itself, does not have the force of law unless it is officially adopted by a regulatory authority. Since regulatory authorities can adopt the Standard with certain exceptions or additional requirements, the regulatory authority of the relevant jurisdiction should be consulted in order to establish the extent to which this Standard has been adopted. Where this Standard conflicts with regulatory requirements, the regulatory requirements take precedence.

The following publications were consulted during the development of this Standard: City of Calgary

Stormwater Source Control Practices Handbook (2007) and Bioretention and Bioswales (2016).

This project was made possible through the generous support of the National Research Council of Canada as part of its Climate Resilient Buildings and Codes Infrastructure initiative

This Standard was prepared by the Subcommittee on Construction of Bioretention Systems, under the jurisdiction of the Technical Committee on Green Infrastructure for Stormwater Management and the Strategic Steering Committee on Natural Resources, and has been formally approved by the Technical Committee.

This Standard has been developed in compliance with Standards Council of Canada requirements for National Standards of Canada. It has been published as a National Standard of Canada by CSA Group. Notes:

1. Use of the singular does not exclude the plural (and vice versa) when the sense allows.

2. Although the intended primary application of this Standard is stated in its Scope, it is important to note that it remains the responsibility of the users of the Standard to judge its suitability for their particular purpose.

3. This Standard was developed by consensus, which is defined by CSA Policy governing standardization — Code of good practice for standardization as “substantial agreement. Consensus implies much more than a simple majority, but not necessarily unanimity”. It is consistent with this definition that a member may be included in the Technical Committee list and yet not be in full agreement with all clauses of this Standard.

4. To submit a request for interpretation of this Standard, please send the following information to inquiries@csagroup.org and include “Request for interpretation” in the subject line:

   1. define the problem, making reference to the specific clause, and, where appropriate, include an illustrative sketch;

   2. provide an explanation of circumstances surrounding the actual field condition; and

   3. where possible, phrase the request in such a way that a specific “yes” or “no” answer will address the issue.

      Committee interpretations are processed in accordance with the CSA Directives and guidelines governing standardization and are available on the Current Standards Activities page at standardsactivities.csa.ca.

5. This Standard is subject to review within five years from the date of publication. Suggestions for its improvement will be referred to the appropriate committee. To submit a proposal for change, please send the following information to inquiries@csagroup.org and include “Proposal for change” in the subject line:

   1. Standard designation (number);

   2. relevant clause, table, and/or figure number;

   3. wording of the proposed change; and

   4. rationale for the change.

October 2018 © 2018 Canadian Standards Association 8

W201-18 Construction of bioretention systems

W201-18

Construction of bioretention systems

0 Introduction

The National Research Council of Canada’s initiative for green infrastructure to support flood mitigation and surface water protection led to the development of two CSA Group standards for the design and for the construction of bioretention systems: CSA W201, which focuses solely on the construction aspect of bioretention systems, and CSA W200, which focuses on design aspects of bioretention systems.

Bioretention systems employ a site-integrated design that provides opportunity for stormwater infiltration, treatment, storage, and biological uptake by plant material. Data suggests that these systems, when properly designed, constructed, and maintained, perform well over long periods of time. Indeed, proper design of bioretention systems is critical to their long-term success, which is only carried through with proper construction techniques, which include erosion and sediment control measures, prevention and alleviation of soil compaction, and construction sequencing.

Erosion and sediment control measures prevent clogging of bioretention media and geotextiles. It is critical to keep sediment out of bioretention systems during and after construction in order to prevent failure of the system due to loss of infiltration potential.

Prevention and alleviation of soil compaction is also crucial during construction of bioretention systems because compaction can reduce infiltration rates in sandy soils by an order of magnitude and in clayey soils by a factor of 50. Soil compaction can become so severe that plant material and soil microbes can no longer thrive, rendering natural processes incapable of reversing the impacts of soil compaction. As such, techniques such as soil scarification are often necessary to alleviate compaction on construction sites because they loosen the soil faster than natural processes.

Activities on a construction site are sequenced properly to avoid the erosion, sedimentation, and compaction issues described above. Where practical, bioretention systems are usually constructed after all other activities on site or as close to the end of the site construction schedule as possible.

1 Scope

1.1

This Standard covers the construction considerations for bioretention systems.

1.2

This Standard covers the following items:

1. roles and responsibilities;

2. contract documentation;

3. construction sequencing;

4. erosion and sediment control for bioretention systems;

5. construction documentation;

6. material supply and handling;

7. installation considerations;

8. landscape materials and maintenance;

October 2018 © 2018 Canadian Standards Association 9