Last spring Ducks Unlimited and the Idaho Department of Fish and Game (IDFG) completed a large-scale restoration of Fort Boise Wildlife Management Area (WMA), one of the state’s most popular wildlife attractions which draws 40,000 visitors, and about 65,000 migrating white geese, per year.
Fort Boise serves a vital role for Idaho’s migrating and breeding waterfowl. It’s a diverse assemblage of wetland resources among Idaho’s vast sea of farms, deserts, mountains, and increasingly, suburban sprawl.
Fort Boise sits along the Boise River at its confluence with the Snake River in southwest Idaho, about 50 miles from the city of Boise. Sand Hollow Creek is the primary source of water for most of the 500 acres of wetlands managed on the WMA. Sand Hollow Creek also serves as Fort Boise’s greatest impediment to providing abundant waterfowl resources. For decades Fort Boise was plagued by sediment delivered by Sand Hollow Creek from the surrounding uplands. Further confounding the dilemma was the role Fort Boise wetlands played in filtering the sediment out of the water before it flowed into the Snake River. Annual accumulation of sediment has filled the Fort Boise wetlands and distributed invasive plants throughout the WMA. With little capability to manage the wetland units, Fort Boise managers have slowly watched the wetland resources deteriorate with little recourse.
Following a technical assessment by regional wetland experts in 2019, a restoration plan for about 570 acres was formed with two primary restoration objectives. The first was the need for an improved and repeatable sediment removal system, capable of removing higher amounts of sediment from the incoming water. The second was providing water management capability to IDFG staff to maximize wetland potential.
At the diversion of Sand Hollow Creek, a water-control feature was designed to serve as a settlement basin for sediment prior to entering the wetland units.
The plan proposed to remove nearly 115,000 cubic yards of accumulated sediment from the wetland units to restore their native substrate elevations. Forty-four new water-control structures and 2,000 feet of pipeline were installed in addition to the enhancement of 30,000 feet of levees for water management.
Construction began in August 2020 and continued through its completion in April. IDFG managers kept the units dry temporarily following construction to conduct prescriptive burning and aggressive weed control. By May, water began flowing into the newly restored units and the wetland vegetation responded immediately. Despite widespread drought in the Intermountain West, the reliable water of Sand Hollow Creek will allow the units to be in optimum condition for the fall migration of waterfowl.
Despite the completion of the broader restoration, IDFG and DU are not idling their efforts on Fort Boise. DU engineers are already working with Fort Boise managers to restore hydrology to more than 100 acres of wet meadow units that have been dry and fallow for more than a decade. With the financial support of the Orndorff brothers and matching contributions from the Microsoft Corporation, a restoration plan is being developed that will restore infrastructure and enhance water management capabilities across these wet meadows.
Scheduled for implementation this year, these restored wet meadow features will provide staging resources for the spring migration.
Ducks Unlimited Inc. is the world's largest nonprofit organization dedicated to conserving North America's continually disappearing waterfowl habitats. Established in 1937, Ducks Unlimited has conserved more than 15 million acres thanks to contributions from more than a million supporters across the continent. Guided by science and dedicated to program efficiency, DU works toward the vision of wetlands sufficient to fill the skies with waterfowl today, tomorrow and forever. For more information on our work, visit www.ducks.org.