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

Large historic homes and white picket fences line a street.

The End of Single-Family Zoning in Arlington County, Virginia

Arlington County is the latest jurisdiction in the country to effectively end single-family zoning.

March 23, 2023 - The Washington Post

Amtrak Acela Express train passing through Harrison station in Newark, New Jersey

‘Train Daddy’ Andy Byford to Oversee Amtrak’s High-Speed Rail Efforts

Byford, who formerly ran NYC Transit and Transport for London, could bring renewed vigor to the agency’s plans to expand regional rail in the United States.

March 28, 2023 - StreetsBlog NYC

Buses in downtown Seattle on the dedicated 3rd Avenue bus lanes

Seattle Bus Lane Cameras Capture Over 100,000 Violations

An automated traffic enforcement pilot program caught drivers illegally using transit lanes more than 110,000 times in less than a year.

March 28, 2023 - Axios

View of Statue of Liberty with New York City skyline in background

Immigration Grows, Population Drops in Many U.S. Counties

International immigration to the country’s most populous areas tripled even as major metropolitan areas continued to lose population.

March 31 - The New York Times

Detroit Sports Arena

$616 Million in Development Incentives Approved for District Detroit

The “Transformational Brownfield” incentives approved by the Detroit City Council for the $1.5 billion District Detroit still require approval by the state.

March 31 - Detroit Free Press

A red sign reads, “Welcome to New Canaan.”

Affordable Housing Development Rejected for Lack of Third Staircase in Connecticut

The New Canaan Planning Commission rejected a development proposal, including 31 below-market-rate apartments, for lack of a third staircase, among other reasons, at a time when advocates are pushing to relax two-staircase requirements.

March 31 - Stamford Advocate

New Updates on PD&R Edge

HUD's Office of Policy Development and Research

HUD’s 2023 Innovative Housing Showcase

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.