The July 3rd thunderstorm, the second such storm to hit Orleans in the past 8 years, dropped about 70 millimetres of rain over an hour causing many streets and basements to be flooded.   These types of floods are likely to become more numerous as the City continues to allow development to encroach into the natural drainage systems in various parts of the City.  The costs of repairing such flood damage should convince decision makers that protecting the natural drainage system make good financial and environmental sense.

	From Ottawa Metro, July 5: Richard Hewitt, deputy city manager of public works, said yesterday there’s nothing wrong with drainage in the area. It was simply overwhelmed by a heavier than usual rainfall, he said. “None of our systems can handle that kind of event,” said Hewitt. “Three inches is a heck of a pile of water in that short time. With strong flows, you’re talking many times the diameter of the pipes. They are not designed for that extreme of an event. Unfortunately there is going to be flooding that occurs.” When piping is “over taxed” water will go wherever it can, he said. Such comments could be valid in older parts of the City, but surely not in such a recently built community as Orleans.
	Modern stormwater management involves consideration of both "major system flow" (i.e. overland flow), and "minor system flow" (i.e. in storm sewers). The minor system is normally required to convey rain storms up to the "5-10 year event", and what isn't captured in the minor system (i.e. what is draining through storm sewers) is converyed along the major system (i.e. running along roads, swales, ditches, tributaries, rivers etc.) This "major/minor system" approach has been around for years, what happened in Orleans?
	This geyser is caused by water rushing from storm sewers (minor drainage system) sitting higher in elevation compared to the sewer running along the street.   As is evidenced in Kanata West, the City continues to underestimate the importance of protecting the natural drainage system.  Ottawa is somewhat unique in that most municipalities in other parts of the province don't eliminate / fill in many of the small tributaries during urbanization as does the City.  The City's approach all too often sees the replacement of natural drainage functions with engineered storm sewers with the result that the minor system is burdened with flows that in other municipalities would have already discharged into a major system.
	The reason for the elimination of the tributaries is to maximize the use of land for development. The tributaries are replaced by storm sewers on the basis of findings in non-calibrated engineering models that are prepared by the developer's engineering consultants.
	Will things improve in Orleans, not likely!  The Official Plan shows that a future employment area is to be built south of Innes Road.  This is the same general area of  the Belcourt drainage system.  There is likely another 100 acres or more of intense development south of Innes Road that will need to drain through the Belcourt drainage system - a system that, based on observation during and after the July 3 storm is already over-taxed.  This additional development area will exacerbate existing problems, and is likely to increase the frequency in which flooding will occur.

The City is currently developing a Stormwater Management Strategy, perhaps the best advise for new areas of development is to provide more protection to natural drainage systems in order to prevent more Orleans type floods.