OMAHA, Neb. -- The U.S. Army Corps of Engineers, Omaha District (Corps) has conducted an environmental analysis in accordance with the National Environmental Policy Act of 1969, as amended. The final Integrated Feasibility Report and Environmental Assessment (IFR/EA) dated July 2022 for the Lower Brule North Ecosystem Restoration Project addresses ecosystem restoration and cultural and natural resource preservation opportunities in Lyman County, South Dakota adjacent to and north of the town of Lower Brule. The study and assessment were conducted under the Tribal Partnership Program (TPP). The resulting report proposes a Recommended Plan that will restore critical riparian and wetland habitats to be implemented as two separable projects under Section 203 of the Water Resources Development Act of 2000 (WRDA 2000), as amended (33 U.S.C. § 2269).
The final version of the report can be reviewed here: https://www.nwo.usace.army.mil/Missions/Civil-Works/Planning/Planning-Projects/Lower-Brule-North-Shoreline-Ecosystem-Restoration/
BACKGROUND:
The construction of the Big Bend Dam/Lake Sharpe project inundated thousands of acres of pristine Missouri River bottomland floodplain forests, significantly altering the landscape, and degrading natural and cultural resources along the Lower Brule Sioux Reservation. Remnant riparian, wetland, and cultural resources have been further lost and degraded by continual shoreline erosion, due to wind driven waves and ice-action in the years since the reservoir was constructed. This includes degradation of the quantity and quality of aquatic and riparian habitats. Unlike many reservoirs, Lake Sharpe is operated as a re-regulation reservoir. Thus, the pool elevation remains relatively stable, and only fluctuates by about one foot, regardless of pool levels and releases from the other five Missouri River mainstem reservoirs. Native riverine, emergent wetlands, and riparian habitats once abundant along the shores of the Missouri River (before construction of Big Bend Dam) were a significant economic, cultural, and spiritual resource to Native American Tribes.
A feasibility study evaluated alternatives to restore and preserve nationally significant natural resources along approximately 3.9 miles of shoreline to the north of the Lower Brule community. The primary goal is to restore degraded aquatic, wetland, and riparian habitats for fish and wildlife, while incorporating robustness and resiliency so the restored habitats will be sustainable. Restoring these resources will contribute significantly to preserving cultural, spiritual, and ceremonial flora, and maintaining cultural traditions that revolve around the Missouri River, its floodplain environment, and its natural resources.
The Recommended Plan consists of four reach-based measures to restore wetland and riparian habitat and will contribute to preserving and maintaining cultural traditions that revolve around the environment and natural resources. Each of these reach-based components is described below:
- Reach 1 consists of construction of a 100-foot-wide riparian planting bench and gravel maintenance path to protect the area from erosion. This measure creates approximately 4.5 acres of riparian habitat.
- Reach 2 consists of construction of a 100-foot-wide riparian planting bench, gravel maintenance path, and 2,400-foot-long offshore breakwater with a 50-foot-wide planting bench. The protected open water area between the offshore breakwater and the existing shoreline is expected to create an approximately 8.8-acre emergent wetland. The measure also creates approximately 8 acres of riparian habitat.
- Reach 3 consists of construction of a 100-foot-wide riparian planting bench, gravel maintenance path, stone-toe revetment, and 2.12-acre peninsula protected by a 920-foot-long L-head dike. The peninsula is being designed so that it will have many plantings of various native plants that were common along the river The protected open water area between the L-head and the peninsula will create a 3.75-acre emergent wetland. The measure also creates approximately 17 acres of riparian habitat.
- Reach 4 consists of construction of a 100-foot-wide riparian planting bench, gravel maintenance path, and 200 x 1,500-foot island that would be constructed in the lake in water up to three feet deep. The island would be planted with cottonwood trees and other culturally significant plants. The lakeward side of the island would be protected from wind/wave and ice erosion through construction of a riprap revetment. The protected open water area between the island and the shoreline is expected to create an approximately 5.17-acre emergent wetland. The measure also creates approximately 32 acres of riparian habitat.
Integrated with the habitat restoration, the Recommended Plan incorporates resilient design to withstand wind-wave and ice-shove erosive forces preserving 450 acres of Tribal lands and cultural resource sites and infrastructure that otherwise would be lost over the next 50 years. The Recommended Plan includes restoring landscape features and accessibility for Tribal members to reconnect with the Missouri River and its natural environment. Regaining access to the river will provide younger generations the connection to the river that has been previously lost. Reintroduction of medicinal and culturally significant plants will provide younger generations historical knowledge and allow reintroduction of spiritual practices. An island would provide all Lower Brule Sioux Tribal members with land features that were lost when the reservoir was filled.
The first separable project would be implemented as early as possible and covers Reaches 1 through 3 of the study area (roughly 12,000 feet of shoreline). Total shared costs for this project are estimated at $18.4 million, with the Federal share being $16.8 million and the non-Federal share being $1.6 million. The second separable project covers Reach 4 of the study area (roughly 8,000 feet of shoreline) and could be implemented concurrently with the first project, if funded, but likely would be sequenced to be implemented as early as possible after the first project is complete. Total shared costs for this project are estimated at $17.5 million, with the Federal share being $16.0 million and the non-Federal share being $1.5 million.