Changes

Flooding is a major environmental and economic challenge, particularly in urban areas where impervious surfaces prevent natural infiltration. Flooding can result in traffic interruption, economic loss, infrastructure damage, basement flooding and other undesirable consequences. [[Climate change]] is increasing the frequency and intensity of extreme rainfall events, exacerbating flood risks. This will be particularly severe in older areas where the minor system was not designed to today’s standards and/or major drainage system pathways have been altered or do not exist. Catastrophic losses from flooding have been steadily rising in Canada over the last two decades.

Flooding is a major environmental and economic challenge, particularly in urban areas where impervious surfaces prevent natural infiltration. Flooding can result in traffic interruption, economic loss, infrastructure damage, basement flooding and other undesirable consequences. [[Climate change]] is increasing the frequency and intensity of extreme rainfall events, exacerbating flood risks. This will be particularly severe in older areas where the minor system was not designed to today’s standards and/or major drainage system pathways have been altered or do not exist. Catastrophic losses from flooding have been steadily rising in Canada over the last two decades.

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"Hydrological changes associated with urbanization are increased storm runoff volumes and peak flows, faster flow velocities and shorter time of concentrations. A reduction in infiltration generally leads to less groundwater recharge and baseflow. The flashy response results in tremendous stresses for the urban stream and downstream receiving areas" (Walsh et al., 2005)<ref>Walsh, C. J., A. S. Sharpe, and D. A. Burns. 2005. "The urban stream syndrome: Current knowledge and the search for a cure." Journal of the North American Benthological Society 24(3): 706–723. https://doi.org/10.1899/04-028.1</ref>}}

"Hydrological changes associated with urbanization are increased storm runoff volumes and peak flows, faster flow velocities and shorter time of concentrations. A reduction in infiltration generally leads to less groundwater recharge and baseflow. The flashy response results in tremendous stresses for the urban stream and downstream receiving areas" (Walsh et al., 2005)<ref>Walsh, C. J., A. S. Sharpe, and D. A. Burns. 2005. "The urban stream syndrome: Current knowledge and the search for a cure." Journal of the North American Benthological Society 24(3): 706–723. https://doi.org/10.1899/04-028.1</ref>}}

In order to protect downstream properties from flooding due to upstream development, Conservation Authorities establish flood control for future stormwater management planning through regularly updated of Hydrologic and Subwatershed Studies that characterize flood flow rates, define the location and extent of  flood-prone areas, and assess the potential impact of further urbanization.

In order to protect downstream properties from flooding due to upstream development, Conservation Authorities establish flood control for future stormwater management planning through regularly updated of Hydrologic and Subwatershed Studies that characterize flood flow rates, define the location and extent of  flood-prone areas, and assess the potential impact of further urbanization.