In a report prepared by the Montana Department of Natural Resources a quagga and zebra mussel worst case scenario invasion would cost Montana an estimated $234 million per year in damages to the Montana economy.
Recreation, a big driving wheel to the state and local economy, would be negatively impacted by an estimated $122 million per year. An invasion would severely damage the state’s fisheries, a big recreation and tourist draw. An invasion would damage boats, motors and recreational equipment. Mussels could also be a pain to water recreationalists when they get established on docks, beaches, boat ramps and watercraft.
Agriculture, a big cog in the state’s economy, would be negatively impacted by $61 million per year. There are 2.5 million acres of irrigated land in the state, which accounts to 96 percent of surface water withdrawals. An invasive mussels can infest irrigation system reservoirs, feeder water bodies, pipelines and canals as well clog irrigation pumps, screens and head gates, thus reducing pumping capacity. Combatting the invasion breaks down to an estimated additional charge of $5.75 per acre-foot of water due to increased operation and maintenance needs.
Infrastructure related to hydropower, thermoelectric power, industrial operations, water treatment plants, mining operations, and self-supply domestic wells and pipes are all in danger of depredation as a result of an invasive mussel in state water bodies. They could restrict or clog infrastructure intake flows thus reducing the conveyance water that could result in the shutdown of operations for maintenance. Those impacts would be an estimated $47 million per year.
Government revenue would dip, especially for local governments, with an invasive mussel incursion. For instance, state lakefront or waterway frontage properties could decrease in value by an estimated $500 million for an estimated loss of $4 million per year in property tax revenue for state and local governments. Flathead, Whitefish and Swan lakes water front property amounts to 78 percent of the total lakefront value in Montana.