bluebelt

Compound of blue +‎ belt, referencing the colour of water.

bluebelt (plural bluebelts)

1. A drainage system just outside a city which helps protect it from flooding.
   • 2018 May 26, “Green Leader Mike Schreiner pledges to expand Greenbelt into 'bluebelt'”, in CBC News‎, archived from the original on 2022-12-01:

     Generally speaking, the bluebelt is a stretch of watersheds that stretches along the edge of the Greenbelt. The plan endorsed by Schreiner would protect vulnerable water sources in the GTHA, the Bruce Peninsula, Brant County, Simcoe County, Northumberland County and Waterloo region.

   • 2023 July 15, Hilary Howard, “New York Is Preparing for More Floods. Will It Be Enough?”, in The New York Times‎, New York, N.Y.: The New York Times Company, →ISSN, →OCLC, archived from the original on 2023-07-19:

     So-called bluebelts in the city connect storm sewers to lakes and ponds, conveying excess water to these natural holding areas. This helps reduce, if not eliminate, flooding on streets and in basement apartments, Mr. Aggarwala said. He pointed to the New Creek Bluebelt, part of a larger Mid-Island Bluebelt project and one of almost 90 such ventures in Staten Island, as an example. "It's in operation and it's beautiful; the neighbors love it and it's eliminated flooding in that part of Staten Island."

• green belt