Rainwater Catchment

Rainwater Harvesting

Rainwater Collection as a Stormwater Management Tool

Rainwater collection has traditionally been viewed in the “beneficial use” context.  However, given the issues stormwater presents in urban areas laden with impervious surfaces (Puget Sound region), rainwater collection as a stormwater management tool is getting renewed attention.

In the Puget Sound region and in some other urban areas of the state, stormwater and wastewater sometimes share the same pipe – these are called combined sewer systems.  Large storm events can create so much stormwater that the capacity of the combined sewer is exceeded and as a result, excess flows into local lakes, streams or the Puget Sound – this is called a combined sewer overflow (CSO).

Capturing rainwater before it becomes stormwater not only decreases the amount of stormwater that needs to be treated, it also decreases the amount of water that quickly runs off the land into local streams, often scouring them in the process.