Changes

===Safety===

===Safety===

As shallow grassed swales are a common roadside construction, the Ministry of Transport has created their own guide to maximum flow depth and freeboard. However that advice has been prepared for a specifically high risk environment and those constraints should not be applied to all circumstances. In many urban environments the principle of applying check dams to enhance all surface BMPS can be safely used to encourage ponding and infiltration for a day or two.

As shallow grassed swales are a common roadside construction, the Ministry of Transport has created their own guide to maximum flow depth and freeboard<ref>Ontario Ministry of Transportation, & Ontario Ministry for Transportation. (2016). Stormwater Management Requirements for Land Development Proposals. Retrieved February 26, 2018, from http://www.mto.gov.on.ca/english/publications/drainage/stormwater/section8.shtml#controls</ref><ref>Drainage and Hydrology Section Transportation Engienering Branch Quality and Standards Division. (1997). MTO Drainage Management Manual. Retrieved from http://www.ontla.on.ca/library/repository/mon/12000/198363.pdf</ref>. Their advice has been prepared specifically for high risk environments and those stringent constraints should not be applied to all circumstances. In many urban environments the principle of applying check dams to enhance all surface BMPS can be safely used to encourage ponding and subsequent [[infiltration]] for a day or two.

==Design==

==Design==