CSA W210:21

Preface 

This is the first edition of CSA W210, Prioritization of flood risk in existing communities. 

The purpose of this Standard is to provide voluntary guidance on a flood hazard and vulnerability screening framework. The purpose of the screening is to support the process of prioritizing flood risk areas within an existing (previously developed) community comprised of residential and mixed uses. This Standard provides a transparent, evidence-based, and defensible framework that supports resource allocation decisions regarding flood risk-reduction at the community level. 

Users of this Standard are reminded that additional and site-specific requirements could be specified by federal, provincial/territorial, municipal, or other authorities, or by a project owner. This Standard should not be considered a replacement for the requirements contained in any:

 a) applicable federal/territorial, or provincial statute; 

b) regulation, license, or permit issued pursuant to an applicable statute; or 

c) contract that an owner has with a contractor. 

CSA Group gratefully acknowledges the generous support of the Standards Council of Canada in helping make the development of this Standard possible. 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. 

Scope 

1.1 General 

This Standard outlines voluntary guidance associated with a flood hazard and vulnerability screening framework. The purpose of the screening framework is to aid in the process of prioritizing flood risk-reduction work within existing communities. This Standard provides a) a guide to users; b) references to related publications; c) definitions for use in the Standard; d) a description of flood mechanisms; e) context of climate change considerations; f) approaches to prioritizing flood resilience works; and g) an overview of possible best practices. 

1.2 Guiding principles and criteria 

This Standard for existing communities (as opposed to new or recently planned communities) is guided by a number of principles and criteria which are intended to support the development and application of this Standard in various jurisdictions across Canada. This Standard is intended to support unbiased and transparent decision-making related to those locations within a municipality which are deemed to be most vulnerable to flooding. Once identified, these areas would be the priority for more advanced flood risk analysis, development and design of solutions, and/or flood mitigation investment. 

The principles include 

a) the consideration of the full range of flood mechanisms present in a community; 

b) the consideration of interdependency between various flood mechanisms in establishing flood risks; 

c) the consideration of site-specific conditions, as well as existing community planning policies and principles, in the determination of flood risk; and 

d) the consideration of flood-exacerbating factors such as climate change (future frequency and severity of precipitation), urban intensification, and changes in upstream land uses that affect long-term resilience. 

This Standard is not intended to replace local, provincial, federal, or territorial directives related to infrastructure planning and design. It is to be viewed as a complement to existing CSA standards and those guidance initiatives. Common requirements in some jurisdictions are referred to in Annex D. Note: While increases in runoff due to climate change have received more attention, the impacts of uncontrolled intensification might actually be more severe if left unchecked. For instance, climate science suggests that rainfall intensities could increase by 30% to 40% by 2100 in some areas, while in some others decreases in local intensities are projected. In comparison, doubling the imperviousness from 30% to 60% might increase the runoff by more than 100%. This highlights the need for appropriate stormwater controls as part of integrated land use policies in communities subject to not only climate change, but intensification as well. 

1.3 Topics in and out of scope The following summarizes those topics within and outside of the scope of this Standard. Geography - In scope:  Canadian communities located below the 60th parallel north (i.e., southern communities) Out of scope: Communities north of the 60th parallel, including permafrost communities  Flood hazards - In scope:  Riverine (fluvial) Overland (pluvial) Storm and sanitary sewer black-up infiltration (see page) High lake levels Out of scope:  Tidal/coastal Storm surge, and sea level rise Unique flood hazards (e.g., dam failures, tsunami, etc.) Ice jams Development type - In scope:  Urban and

Product Details

Published:

12/09/2021

ISBN(s):

9781488338496

Number of Pages:

71

File Size:

1 file , 1.2 MB

Product Code(s):

2429523, 2429526, 2429523, 2429526

Note:

This product is unavailable in Russia, Ukraine, Belarus