The project site, a 0.6-acre overflow parking lot for visitors to the Zoo and Park drains to Atascadero Creek, a trout-bearing stream. The City of Atascadero wanted to create a green parking lot that is compatible with the Zoo’s theme of conservation and the City’s priority for creating green spaces within the urban area.
The existing gravel and asphalt overflow lot sloped steeply and directed the majority of untreated stormwater runoff to storm drains that discharged to the Atascadero Creek.The existing bathtub-like surface grade of the lower lot provided an opportunity to incorporate a permeable paver system with aggregate storage beneath, with reduced excavation requirements. The City received an Urban Greening Grant, which was combined with additional City funds to complete the design and construct the project.
Working with the City, LIDI prepared a schematic drainage plan for the parking lot that incorporated permeable pavers, bioretention, and use of LID site design principles (e.g., “passive landscape”) to mimic the processes and functions of a predevelopment landscape, allowing stormwater to slow, spread and sink in. The City hired North Coast Engineering and Casey J Patterson, Landscape Architect to take the project from schematic design through construction documents. Plans for the new green lot were completed in July, 2013 and major construction wrapped up in December, 2013. The site’s LID treatment and infiltration design provides removal of urban pollutants previously directed to the creek; reduces surface runoff volumes; provides groundwater recharge for the Atascadero Sub-Basin Aquifer; and, supports summer base flow to creek. The landscape includes 27 new trees and a drought tolerant, mostly native plant palette that combines beauty with ecological function. User amenities such as a picnic area near the creek and interpretive signage create a welcoming green space that blends seamlessly with the surrounding park. The project also serves as a regional demonstration for different permeable paver styles.