CONCRETE PIPE Lethbridge The City of Lethbridge Design Standards state the following with regards to oil/grit separator design: New developments must include measures to improve stormwater quality. Specifically, Alberta Environment’s Municipal Polices and Procedures Manual requires “a minimum of 85% removal of sediments of particles size 75 microns or greater.” Erosion and sediment control must be in place as permanent features of development. These include grassed swales and runways to trap silt and ponds designed with dimensions and detention times promoting settling. Further, the Design Standards detail the following with respect to reducing hazardous chemical, petroleum products, pesticides and herbicides from stormwater: i. Stormwater containment and treatment will be required for developments purposing to use hazardous materials on site. It is recommended that Developers contact the City Engineer at the concept stage when considering these types of facilities. ii. Stormceptors or other oil and grit separators should be considered for any development with large parking areas or where there is a risk of a petroleum product spill. iii. Stormceptors or an approved alternate oil and grit separator will be required at all sites containing gas stations. The device shall be installed in an easement or in public property to allow access by City forces for maintenance and cleaning. PAGE 42 LAFARGE PIPE eMANUAL