Gov. Jared Polis on Wednesday signed a bill committing the state of Colorado to pick up about a fifth of the cost of the Colorado River District’s planned purchase of the historic Shoshone hydroelectric power plant water rights.

The bill providing $20 million toward the purchase was one of several water bills Polis signed Wednesday. Its signing comes about one week after two upper Eagle River water providers committed a combined $1 million toward the $99 million purchase.

The 15-county river district is trying to buy the highly senior water rights for the Glenwood Canyon plant from Xcel Energy. They include a right to flows of 1,250 cubic feet per second dating back to 1902, and a right to 158 cfs that was appropriated in 1929. At times when river flows are limited, they prevent upstream water diversions involving junior rights in order to keep the plant operating, which also keeps more water in the river for the benefit of imperiled fish, recreation uses and downstream water users.