Canadian municipalities are continually challenged with stormwater management. Policies that do exist from an intergovernmental outlook are not contiguous, there are gaps between the positions of the federal, provincial , and municipal legislation. Municipalities are often trying to manage something that is beyond there scope of knowledge or ability.
Municipalities often try to handle their particular situation through implementation of stormwater management objectives in the form of Best Management Practices (BMP). These management practices are typically learned through guidelines and handbooks. There are three methods of managing stormwater based on the location of the stormwater within the runoff cycle. At the source we have lot-level controls. The aim is to lessen the flow and control the quality of the runoff on site before it reaches the storm sewer system. Conveyance controls are what is done in the actual stormwater systems, for example storm sewers or open channel systems. here the aim is to reduce the flow and control the flow before the water is discharged into the lakes or oceans. Storage of the water attempts to stagger the inflow of the runoff into the receiving waters so as not to cause flooding. The last method is the end of pipe controls, meaning treatment facilities just before the water is released into the receiving waters. The size of these facilities can depend on the effectiveness of the first two methods.
Municipalities all have somewhat unique sets of challenges they have to face based on their own location in a specific watershed. The Stormwater Management Planning and Design Manual provides a base guideline and then each municipality tailors there approach.
A important idea is that is easier to address a problem at it’s source than to have to restore a harmed ecosystem. Municipalities and developers are trying to look at better lot level controls, but hard evidence of exactly what to do and what works best is sparse or inconclusive. Other considerations in source control are lack of municipal control over private property, and how the controls are perceived by the public. Do the public back the effort or are the efforts a nuisance?
Urban stormwater management is never straight forward, involving many stakeholders with possibly differing priorities. Outreach and education is critical. Projects and costs have to be understood. Apathy and opposition are possible. Balancing municipal objectives and public involvement is an ongoing challenge, a breach of public trust is a difficult act to undo.
At present, when designing a new stormwater management system historical weather patterns are used to predict what is going to be required. Little or no consideration is given to the effect of climate change, the potential impact could be huge , but is not fully understood.
Regulatory agencies have their work cut out for them. An integrated approach to planning and implementation is crucial. Economic, social, and environmental concerns need to be addressed by various levels of government and across various disciplines.