The District considers cost-benefit when deciding which project to implement; not all potential projects are necessarily good investments.
The District evaluates the cost-benefit of every project it undertakes. Phosphorus is a major nutrient affecting water quality in Minnesota lakes and streams, and is therefore a high priority factor for which the District evaluates cost-benefit. Most of the project pages on this website indicate a phosphorus reduction cost-benefit (i.e., cost per pound of phosphorus removed over the lifecycle of the project). The estimated cost takes into consideration the cost of project development/design (e.g., staff time), construction (e.g., labor and materials), and post-construction operations & maintenance (e.g., cleanouts and equipment replacements). The estimated annual phosphorus reduction is multiplied by the number of years for which the project is expected to function, in order to get a total life cycle phosphorus reduction (e.g., 100 pounds per year x 25-year lifecycle = 2,500 pounds removed over the project lifecycle). Divide the total lifecycle cost by the total lifecycle phosphorus reduction to get the lifecycle cost-benefit (cost per pound).
A cost-benefit below $1,000/lb is generally considered acceptable. Most of the District’s capital improvement projects have a phosphorus reduction cost-benefit below $500/lb and many are even below $100/lb.