Again in the theme from In the Key of Charles this morning: water, I suggest reading this publication from the Ontario Clean Water Agency: Beautiful Lawns and Gardens through Water-Efficient Landscaping (pdf). The appendix worth checking out.
Also, an article on and how to create a down-spout bog garden (pdf) from the North American Native Plant Society.
Eco-Superior's rain barrel program
water lilies at the Royal Botanical Gardens
Hamilton/Burlington, Ontario July 2007