Catchment-wide rain gardens and sustainable drainage to cut runoff at source
#00009
Install rain gardens, permeable surfaces and other sustainable drainage (SuDS) across the catchment to soak up rainfall where it lands, cutting peak runoff to overwhelmed drains. Most effective as a dispersed, upstream-weighted network.
Lyon, France
OngoingMetropole de Lyon, ville permeable program · since 2020 · City
Since 2020 the Metropole de Lyon has run a "ville permeable" (permeable city) program, systematically disconnecting surfaces from the sewer network or depaving them so rain infiltrates where it falls. By 2025, 255 hecta…
€286M · Metropole de Lyon, with 53.9 million EUR co-financing from the Agence de l'Eau Rhône Méditerranée Corse for the 2025–27 contract
Chinese national government Sponge City Program (30 pilot cities from 2015), including Zhengzhou municipal government · since 2015 · National
China's Sponge City Program launched in 2015 with 30 pilot cities and over RMB 1 trillion (~140 billion USD) in cumulative national spending, deploying permeable surfaces, rain gardens and green infrastructure at scale.…
CN¥1T · Chinese central and municipal government; cumulative national spending over RMB 1 trillion (about 140 billion USD) · 1 source
Nashville, Tennessee, USA
PartialCumberland River Compact and Metro Nashville (green infrastructure programs) · City
Nashville has pursued green-infrastructure flood mitigation — depaving, tree planting, and rain gardens — as part of its response since the catastrophic 2010 flood. This case study is included specifically for its hones…
1 source
Community BlueScapes (Richmond Council, Barnes Common Ltd., WWT) with Barnes Community Association · 2025 · Neighborhood
A purpose-built rain garden was installed beside the roundabout on Barnes High Street to reduce surface-water flood risk on paved urban areas. It absorbs excess water from storms and heavy rainfall, easing pressure on l…
Defra (via Community BlueScapes partnership) · 1 source