Portland Oregon does something similar on a much smaller scale. To prevent the sewage system from being overwhelmed in periods of heavy rain, they've installed

Portland Oregon does something similar on a much smaller scale. To prevent the sewage system from being overwhelmed in periods of heavy rain, they've installed "swales" and stormwater planters [1] that redirect the water into the ground. I've walked around in the rain and the difference is remarkable--typical curb drains would be overflowing with water, while the drains near the swales and planters would be dry. [1] http://www.oregonmetro.gov/sites/default/files/rain_gardens_and_swales_seminar.pdf http://www.oregonmetro.gov/sites/default/files/rain_gardens_...