green stormwater infrastructure
Without going into too many details, green stormwater infrastructure (GSI) is a relatively new feature in public and private landscapes. Briefly, GSIs are in part plant-based facilities that capture storm water during rain events, holding runoff to allow sediment, trash and other pollutants to deposit while an engineered soil cleans the water. Plants play a large part in this process by capturing certain pollutants in their roots, even using some minerals as nutrients. Once the water is cleaned, there is a number of ways we can take advantage of this source: store for later use, allow it to trickle down into ground water, or allow it to drain into local streams, rivers, and for our region, into the San Francisco Bay and the Pacific Ocean. Clean water, healthy fish, happy people!
The plants listed here are accepted as good candidates to incorporate into GSI, which comprises of rain gardens, bioretention areas, flow-through planters, and tree well filters, to name a few jargon-loaded terms. The technologies are ever evolving, so other opportunities may arise. There are however, a number of considerations before specifying plants within these treatments. For example, plants that normally need ample water will struggle in these primarily drought-stricken facilities when there is no rain. This means supplemental irrigation may be needed, likely even. Because many of these treatments have low elevations that might stay wet in a particularly good year, plants here need to adapt to inundation. By contrast, plants on embankments or at the top of the treatment may be perennially dry, therefore drought tolerance is a major consideration.
For more detailed information, consult the Santa Clara Valley Urban Pollution Prevention Program (SVURPPP) for guidance in developing GSI and accepted plant material. NOTE: GSI is most often designed by experienced engineers and should not be implemented without professional assistance.