New water controls increase flexibility at Benton Lake

Thanks to donations by local wildlife groups, Benton Lake Wildlife Refuge can now control water flows in a way that more closely resembles how water would naturally flow through the area.

The U.S. Fish and Wildlife Service; Montana Fish, Wildlife and Parks; Ducks Unlimited; and the Great Falls Chapter of Pheasants Forever formed a partnership last year to pool funds for a new water control structure at Benton Lake.

Water is pumped into Benton Lake from Muddy Creek through a series of basins and levees that were installed in the 1960s.

Prior to having that infrastructure in place, Lake Creek ran through the area, creating an alluvial fan.

The new water control structure, which is basically a culvert and flow controls, allows water to flow under levees in a pattern that follows the historic Lake Creek channel.

The water control structure was installed last fall and was operated for the first time in March.

"It worked like a charm," refuge manager Rob Bundy said.

The structure allows refuge staff to not only direct water down the historic flow pathway, but also provides enhanced management flexibility to more effectively manage refuge wetlands with less water.

That increased flexibility allowed the refuge to simulate three natural events this spring at the same time.

One unit was left dry as if in a drought, another unit was flooded, and in another, a slow drawdown mimics the drying that occurs over a season.

"That structure helped us be able to do that," Bundy said.

Since the pumps and levees were installed, Benton Lake has always been flooded in the same pattern at roughly the same levels in an attempt to keep water in all the units. With the new structure, a single unit can be a wetland one year and be drawn down another year.

So why would Pheasants Forever want to contribute funds to a wetland restoration project? When wetlands are dry, they create exceptional habitat for nesting and wintering game birds like pheasant, Hungarian partridge, and sharptail grouse, Bundy explained.

That worked out to be true this year, when parts of the refuge were allowed to dry out.

"You couldn't have better pheasant nesting habitat than than," Bundy said, looking out at part of the refuge.

Before installing the water structure, the historic Lake Creek channel was mapped using LIDAR, a technology that uses light to measure distances. The LIDAR data gave managers a better idea of where water used to flow.

The new structure is the first in a series of projects the partnership is pursuing to enhance management flexibility.

The donated funds were used as match towards a North American Wetlands Conservation Act Grant. That grant will provide an additional water control structure in a different area of the refuge that will be installed later this year.