Wetlands in the upper Mississippi and Ohio River watersheds can remove up to 1,800 pounds of nitrogen per acre from field runoff, says a USDA study of the economic benefits of wetland conservation. The authors at the USDA’s Economic Research Service said the study might aid in targeting conservation funds. The department has spent more than $4.2 billion on wetland restoration and protection over the past few decades.
Among the findings in the study: the annualized value of a new wetland on greenhouse gases ranges from zero to $129 an acre; wetlands on farmland don’t provide notable flood-protection benefits unless they are near cities; and the amount of nitrogen that can be removed for each $1 spent on wetland restoration and protection in the upper Mississippi and Ohio River watersheds ranges from 0.2 to 34.0 pounds.