At a Glance

A stormwater management plan helps a botanical garden to recharge groundwater and reduce flooding.

Project Description

Descanso Gardens is an internationally renowned botanical and demonstration garden located just 20 minutes from downtown Los Angeles. With a mission to “cultivate understanding of the natural world and people’s place in it through inspiration, education and example” the site offers visitors ample opportunities to explore its 160 acres of gardens, woodlands and chaparral. Yet the Gardens also experienced insufficient drainage and flooding in its parking lot, extensive impervious cover, noncompliance with Americans with Disabilities Act (ADA) regulations for portions of the parking area, and inadequate operations and maintenance facilities. 

When an electrical fire damaged the Gardens' operations building and maintenance area, the Gardens' staff recognized an opportunity to implement a portion of a master plan prepared by the Portico Group and Biohabitats in 2009.

Biohabitats collaborated with the Portico Group design team and the Gardens' staff in a design charette to develop concepts for a three-acre site to house operations and maintenance facilities, and for the renovation of a four-acre parking lot. 

The resulting conceptual stormwater management plan called for permeable pavement in parking stalls, bioswales intercepting stormwater along each parking row, and a series of bioretention areas along a central ‘Arroyo’ corridor and at strategic low points. The plan not only exceeds the County’s requirement for stormwater filtration and infiltration; it also maximizes groundwater recharge and minimizes overflow into an adjacent regional flood control channel. Additional features of the concept include native, drought tolerant, and specimen plantings; a village of improved operations and maintenance buildings; and solar energy canopies in the parking lot.




Physiographic Province

Los Angeles Ranges


Los Angeles River

Expertise Areas

Infrastructure, Urban Ecology, Water


Los Angeles County


La Cañada Flintridge, California, United States

Project Team
  • The Portico Group