Watershed Symposium 2018

Green Streets: Improving Water Quality and Increasing Conservation

Green streets offer a great opportunity to get multiple benefits out of critical infrastructure. Green streets can be incorporated into street capital improvement plans to reduce overall costs and increased benefits.

Full Abstract
Green streets offer a great opportunity to get multiple benefits out of critical infrastructure. Coordination of green street development to strategically fit into capital improvement programs for both streets and water quality infrastructure is a cost efficient way to improve water quality, improve street aesthetics, and increase water conservation by recharging aquifers. Developing a systematic approach for adding green streets to a capital improvement program requires assessing which streets require repair, determining the potential of the street locations for groundwater recharge, developing standard plans and approaches that are acceptable to the road maintenance and construction groups, and determining funding sources for the various aspects of the project. Green streets can range in construction from traditional streets with inlets for median bioswales, pervious pavements or pavers that allow direct infiltration, capture and irrigation reuse systems, street planter box systems for improved water quality, etc... Design of green streets can be flexible enough to meet the specific requirements of any agency. This presentation provides discussion on a systematic analysis approach for determining which streets are candidates for green street approaches in a CIP. The approach was used to successfully develop planning level maps ranking potential green streets within two watersheds. Examples of green streets that have recently been developed in several cities in Southern California will be discussed to show the versatility of the green street concepts and stimulate ideas.

City of Los Angeles Laurel Canyon Boulevard Green Street – This project included sidewalk improvements and bioswales along 1,300 linear feet of Laurel Canyon Boulevard for LA Sanitation – City of Los Angeles and the Los Angeles Conservation Corps. The project provides increased groundwater recharge, reduces flooding impacts, protects compatible beneficial uses, and improves the neighborhood quality of life. The project collects stormwater runoff from an approximately 120-acre drainage area.

City of Los Angeles University Park Rain Gardens - CWE designed standardized sidewalk planters (rain gardens) to treat stormwater runoff to help address the Santa Monica Bay Beaches Bacteria Total Maximum Daily Load (TMDL). The stormwater planters qualify as Best Management Practices (BMPs) and Low Impact Development (LID) solutions. The project involved demolition and reconstruction of parkways, curbs, and gutters so the planters could be constructed within the public right-of-way.

City of Claremont Foothill Boulevard Master Plan Implementation – The master plan implementation included storm drains, bioswales, and water quality systems and structures over a 2.5-mile stretch of roadway as part of the Foothill Boulevard Master Plan. These improvements included approximately 1,000 feet of new storm drain, minor roadway and intersection improvements, pedestrian improvements, restriping, infill sidewalks, minor lighting improvements, bicycle lanes and protected bicycle lanes, turf removal and drought-tolerant landscaping installation in medians and some parkway areas, bioswales, and stormwater percolation devices.