Green Infrastructure: 8 Ways to Sustainably Manage Rainwater Runoff

Western Harbour, Malmo, Sweden. This dense new urban neighborhood implements rain gardens, constructed wetlands and permeable paving. In addition to green infrastructure, Western Harbour uses an aquifer thermal energy storage system for year-round heating. Photo credit:


8 Promising Tools to Manage Rainwater

From permeable paving to green roofs, a number of cost-effective and sustainable strategies have emerged for managing water closer to where it falls, rather than directing it into pipes.

“While ‘grey’ or traditional infrastructure remains an essential part of safe and effective design for flood control and urban watershed management, it is no longer the only tool in the toolbox,” write Kurt Pelzer and Laura Tam, of the San Francisco Planning and Urban Research Association (SPUR).

Green infrastructure systems, by contrast, harness natural processes to infiltrate, recharge, evaporate, harvest and reuse stormwater. They use soils, topography, vegetation and engineered materials to soften the impact of urban development on water resources and ecosystems in cities. And the benefits of such systems extend beyond stormwater treatment and flood control to include carbon sequestration, recreational amenities, habitat creation and beautification.”


Sink it, Slow it, Reuse it and Move it

Pelzer and Tam explain the mechanics and advantages and disadvantages of eight different tools for sinking, slowing, reusing, and moving rainwater.

  1. Sink it: holds rainwater and slowly infiltrates it into the ground
  2. Slow it: holds rainwater flow and slowly releases it to the sewer system
  3. Reuse it: holds rainwater and uses it to meet non-potable water demands
  4. Move it: directs water flows to a downstream area of storage

Laura Tam is the Sustainable Development Policy Director for SPUR. In this role, she directs SPUR’s work in five major policy areas: green buildings,  water supply, wastewater, energy and climate change. She led SPUR’s  assessment of 42 options for San Francisco to reduce greenhouse gas  emissions, evaluating them by cost and carbon reduction potential, and  making recommendations for climate mitigation priorities for the city  and region.


To Learn More:

To read the complete story posted on the SPUR website, click on 8 Shades of Green Infrastructure. To download a PDF copy, click here.

To describe each green infrastructure technology, SPUR used publications and resources available from the San Francisco Public Utilities Commission, Philadelphia Water Department, NYC Department of Environmental Protection, Seattle Public Utilities and Portland Environmental Services.