Before 1850 when the rain fell on Vancouver, it soaked into the ground, which then fed the over 50 streams which crisscrossed the land. This water which supported a multitude of life then ran to the Burrard Inlet, False Creek and the Fraser River.

Today most of rainwater ends up on asphalt streets and the rooftops of buildings and this water runs into countless sewers which end up in the same surrounding water systems. As the water runs into the sewers, it picks up pollution from cars, residue from asphalt streets and tar roofs and many other small and large volumes of toxic substances that exist on our urban streets today.

While we cannot bring back the original streams, we can work harder to divert storm runoff into green areas that can soak up and neutralize the pollution before it enters the water table below.

For example, one such activity could be to create pocket marshes in parks where there is poor drainage. Parks were often built in marshy areas of streambeds in the first place (eg. Trout Lake, Douglas Park, China Creek Park). We can put back some pocket swamps to drain the water into the ground instead of doing a poor job of diverting the water into sewers to remove it from the area.

http://www.youtube.com/watch?v=uGzbDmgQHTo
http://www.falsecreekwatershed.org/pdfs/falsecreek_swatershedfinal.pdf