Al Zohour Green Triangle — Nature-Based Flood Mitigation Pilot, Amman

Amman's dense, hilly urban fabric channels flash floods through narrow valleys, and the city has mapped 120 high flood-risk points. The Al Zohour Green Triangle pilot in the Ras Al-Ain district, funded by the Government of Japan and delivered by UN-Habitat Jordan with the Greater Amman Municipality, was built between April 2020 and November 2022 and inaugurated on 31 May 2022.

Demonstrate a nature-based drainage model that can substitute or supplement costly grey infrastructure at other flood-risk points across Amman.

The 2,300 m2 site replaces part of the area's grey drainage with a sustainable urban drainage system (SUDS): vegetated bioretention basins and bioswales feeding an underground detention/storage tank that slows and holds peak flows for later reuse via a pump system.

The bioswales provide roughly 750 m3 of retention capacity, feeding an underground tank reported as 2,100-2,500 m3 across sources. Total implementation cost was about USD 465,000.

This is a single 2,300 m2 pilot; no independent hydrological performance study or grey-vs-green avoided-cost calculation has been published, underground tank capacity is reported inconsistently across otherwise credible sources, and there is no public confirmation yet that any of the other 119 mapped sites have been built.