Green Alleys: A New Paradigm for Stormwater Management

Rather than shuttling stormwater away from the city and into the ocean as quickly as possible, Los Angeles is now—slowly—moving toward a ‘city-as-sponge’ approach that would capture and reclaim more water to recharge crucial reservoirs.

2 minute read

February 2, 2023, 11:00 AM PST

By Diana Ionescu @aworkoffiction


Green alley under construction

A green alley under construction in Los Angeles. | SALT / Green alley

A program that installed green infrastructure in Los Angeles alleyways got its first real test last month as massive storms pummeled the region, bringing rain that overwhelmed much of Southern California’s stormwater infrastructure. As Alissa Walker writes in Curbed, thanks to the “green alleys” installed as part of a 2015 project in South Los Angeles, “the resulting stormwater had more opportunities to sink back into the earth: filtering through a row of permeable pavers, directing to pocket planters where creeping fig vines twirl up garage walls, or vanishing into grates labeled ‘drains to groundwater.’”

Walker explains that “a single green alley is able to capture enough stormwater per year to store it in dry wells below the pavers where it can slowly percolate into the groundwater, says Allen Compton, founder of the landscape architecture firm SALT, which designed these alleys.” The alleys connect to the South L.A. Wetlands Park, another key piece of green infrastructure that collects stormwater and provides habitat for local wildlife.

As storms become more intense and unpredictable, paved-over cities like Los Angeles can use permeable materials and sustainable design elements to capture and reclaim stormwater more effectively, recharge groundwater reserves, and prevent damaging floods. But “Because stormwater is still erroneously classified as a waste product, its management is handled by the same department that picks up the trash,” while other efforts are scattered across city and county agencies. According to Walker, Los Angeles is developing an interagency stormwater plan that would streamline and coordinate stormwater management efforts.

Tuesday, January 31, 2023 in Curbed

Aerial view of homes on beach in Maui, Hawaii

Hawaii Passes First Legislation Regulating Short-Term Rentals Statewide

The new law will give counties the power to limit number or short-term rentals and convert existing short-term rental units back into long-term residential housing.

May 13, 2024 - USA Today

Google office building in Virginia.

Virginia Data Centers Draining State’s Water Supply

Being the world’s largest data center hub is having a severe impact on local water resources.

May 9, 2024 - Grist

Entrance to a drive-through car wash at night with green 'Enter' sign.

Ohio Towns Move to Ban New Car Washes

City officials in northeast Ohio are putting limits on how many car wash facilities can open in their towns.

May 16, 2024 - News 5 Cleveland

Grand Coulee Dam in Washington state.

Northwest Power Demand Could Surge as Data Centers, Transportation Electrification Ramps Up

New estimates project a steady increase in electricity demand due to population growth, data centers, and the shift to electric power in homes, buildings, and transportation.

May 17 - Governing

Blurred traffic speeding by on freeway with Los Angeles skyline in background.

California Testing Per-Mile Gas Tax Alternatives

A summer pilot program will test the fairness and efficacy of collection mechanisms for mileage-based fee options.

May 17 - Newsweek

Close-up of 'Pay rent' note in red marker on day 1 of monthly calendar.

After Months of Decreases, Rents Nationwide Are Going Up

Average rents rose by $12 around the country so far this year.

May 17 - Smart Cities Dive

News from HUD User

HUD's Office of Policy Development and Research

Call for Speakers

Mpact Transit + Community

New Updates on PD&R Edge

HUD's Office of Policy Development and Research

Urban Design for Planners 1: Software Tools

This six-course series explores essential urban design concepts using open source software and equips planners with the tools they need to participate fully in the urban design process.

Planning for Universal Design

Learn the tools for implementing Universal Design in planning regulations.