About $21 million in federal funds have been appropriated to Idaho, Montana, Oregon and Washington to help keep invasive quagga and zebra mussels out of state waters.

The invasive mussels can devastate lakes and rivers, affecting water intakes, agriculture, recreation and more.

The Idaho Press reports, to combat this, Northwestern states have banded together to keep the invasive mussels out of their waters.

Lake Winnipeg in Canada is a key example of the devastating impact the mussels. Six years ago, the lake had no signs of mussels. Now, they’ve washed up on the lake shores, piling nearly three feet high for miles on the beach.

An Idaho-specific analysis showed that the small invasive mussels, if introduced in the state, would have a $94 million annual impact on the state, not including the agricultural impact.