It is doubtful anyone in Los Angeles needs convincing about the near-record amount of rainfall that drenched the city this winter. In comparison to drought-stricken winters past – and according to the LA Almanac – Downtown Los Angeles has received approximately 17 inches of rainfall since December of 2016. That’s impressively almost 8 inches more than for the same period of time during a normal winter.
Just over a year ago, AHBE Lab examined three recently constructed AHBE projects, setting out to identify how each were responding to that year’s El Nino storm event. Today we revisit these three sites, curious about each of their performances during this winter’s unusually inclement conditions. Here is what we found:
Monrovia Station Square Transit Village
The Monrovia Station Square Transit Village project included streetscapes envisioned as a sustainable connection between the surrounding neighborhood to the station. The Chilopsis trees shown above are planted in infiltration flow-through planters along Pomona Avenue and have captured recent rainfall, a feature we credit for the healthy tree growth.
Carex alma (Sturdy Sedge) and Muhlenbergia capillaris ‘Lenca’ (Regal Mist Pink Muhly) were grasses specifically chosen for this project, and they appear to have grown in to fill the planters. The Silva Cells installed adjacent to each street tree are topped with permeable pavers, the combination likely helping to increase the size of the trees with an increased amount of rainfall being delivered to the trees’ roots.
Johnny Carson Park
The plants in the now natural bottom stream continues to fill in at this ASLA Southern California Quality of Life award-winning project. Some areas still hold recent rainfall in the creek. Rainwater also appears to be flowing as designed into the restored creek, later to be infiltrated into the sand bottom or to empty into the L.A. River. Various riparian Salix, scrub, and perennial species have grown vigorously adjacent to the stream channel, providing a more natural appearing edge to the restored stream. Ducks have also been spotted swimming in the standing pools of water between storms.
Torrance Stormwater Basin – Entradero Basin
Entradero Stormwater Basin is one of many detention basins in the City of Torrance that mitigates and cleans storm water runoff before it’s released into the Santa Monica Bay. This stormwater basin was integrated into an existing park with baseball fields and playgrounds, so it essentially became a recreational feature for the community park. The park has evolved into a lively and well frequented public space populated with the activity of little leaguers, children playing along the basin edge, water fowl, and residents exercising along with their dogs in tow across the trails.
Thanks to the plenitude of rain this winter the basin is currently filled with water. A pair of geese, a family of ducks, and various others birds currently make the seasonal basin their home. The planting is filling in and working overtime to help clean the runoff water. A restoration ecologist helped AHBE develop a planting palette to correspond with the various levels of inundation along the sloped basin. For example Lupinus spp. and Salvia spp. were planted along the upper slope of the basin where plants are rarely inundated with water, while Frankenia salina inhabit the lower basin where plants are seasonally inundated during the rainy season.
The Entradero Basin provides a natural system for storm water mitigation, but also provides residents trail opportunities to enjoy the basin as a natural feature in the park. The basin appears to be working wonderfully to clean pollutants from storm water runoff and recharge groundwater aquifers by permitting water to slowly infiltrate, while additionally providing habitat for surrounding wildlife – in its entirety, the project is an example of how green infrastructure can be integrated into a community.
This post was authored by Wendy Chan and Jennifer Salazar.