CAN/CSA-S503-15

1 Scope and application 1.1 Scope This Standard specifies provisions for the planning, design, and maintenance of surface drainage systems within northern community boundaries. Provisions for drainage outside the community boundary are not covered by this Standard. Note: Specific resources and expertise are required to address drainage provisions outside the community boundary. These resources and expertise might be beyond the capacity of an individual community. 1.2 Application This Standard specifies provisions for site-level and community-wide drainage system planning, development, and operations. The provisions apply to drainage systems used for the collection, conveyance, detention, and discharge of excess surface water in the form of overland flow, originating from precipitation, snowmelt, or ice melt. Note: Excess surface water is net of precipitation, soil infiltration, and evaporation. 1.3 Exclusions This Standard does not cover a) drainage systems associated with facilities that might inherently produce contaminated drainage, such as i) solid waste management systems and components; and ii) sewage treatment systems and components; b) drainage directly from storm surges in lakes or oceans; c) drainage directly from riverine flooding; d) subsurface drainage; and e) watershed level drainage planning. Note: Certain drainage circumstances are not considered in this Standard because they have requirements that are beyond the resources and expertise of many northern communities. 1.4 Terminology In this Standard, “shall” is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; “should” is used to express a recommendation or that which is advised but not required; and “may” is used to express an option or that which is permissible within the limits of the standard. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate normative clauses from explanatory or informative material. Notes to tables and figures are considered part of the table or figure and may be written as requirements. Annexes are designated normative (mandatory) or informative (non-mandatory) to define their application.