Yahara WINS issues first 24,143 verified credits, announces sales to WEF and Mortenson
MADISON, Wis. — The Yahara WINS Watershed Carbon Project has become the first in the nation to generate verified carbon credits under a new, science-based methodology for avoiding emissions by choosing watershed conservation over water infrastructure. The 24,143 credits issued in January recognize the avoided greenhouse gas emissions achieved through Madison Metropolitan Sewerage District’s choice to create Yahara WINS, a collaborative, rural-urban approach to phosphorus compliance. This sale confirms that choosing land-based solutions over built infrastructure can deliver measurable climate benefits while improving water quality across the Yahara River watershed.
In 2017, the District chose to meet mandated phosphorus limits through the Yahara WINS initiative by investing in watershed conservation, also called adaptive management, rather than building a multimillion-dollar tertiary treatment facility at its Nine Springs Wastewater Treatment Plant. By choosing adaptive management over energy-intensive infrastructure, the 20-year Yahara WINS initiative is projected to avoid about 73,000 tons of carbon emissions.
“WINS proves watershed conservation can be a smarter path to compliance,” said Martye Griffin, Ecosystem Services Manager at the District. “And now the verified carbon credits add another measurable benefit in avoided greenhouse gas emissions. This is a model that other utilities can replicate to help with the costs of meeting Clean Water Act obligations and support climate goals.”
The District has sold 1,000 credits to the Water Environment Federation, which named Madison Metropolitan Sewerage District the carbon offset partner of WEFTEC 2026. It has also sold credits to Minneapolis-based Mortenson, one of the nation’s largest builders. The credits were verified by a third party, Sustainability Science, and issued by Regen Registry in mid-January. They are projected to generate approximately $270,000 in revenue for the District through 2036.
The project required developing new carbon accounting methods. Boulder, Co.-based Virridy, founded by University of Colorado professor Evan Thomas, created the methodology and manages credit sales.
“By valuing avoided emissions, we’re unlocking new financial tools for utilities to achieve compliance and resilience simultaneously,” said Evan Thomas, CEO of Virridy.
Yahara WINS works with municipalities, government agencies, environmental groups, and landowners and farmers to reduce phosphorus runoff and improve water quality; some practices used to achieve this include cover crops, stream buffers, streambank stabilization and more. The approach costs less than conventional treatment while improving soil health, wildlife habitat and water quality throughout the 536-square-mile Yahara River watershed. The project began in 2017 and runs through 2036.
A media fact sheet with additional project details, documentation and links to registry and verification materials is available online.