Fox Run Sewer Project

Majestic Bluffs Campus Infrastructure

North Point Rec Area

Platte Sanitary Sewer Study

Swan Lake Restoration Project

West Yankton Sewer Feasibility Study

Swan Lake Restoration Project

Swan Lake; near Viborg, South Dakota

Swan Lake is a 186-acre natural lake located northwest of Viborg, South Dakota. The Swan Lake Improvement Association had contracted a hydrographic survey of Swan Lake with Eisenbraun & Associates, and it was determined that approximately 1.3 million cubic yards of sediment existed in Swan Lake. The Swan Lake Improvement Association used this hydrographic information to plan their Lake Restoration project. Later, the Swan Lake Improvement Association again contracted with E/A to assist them in planning and designing for the removal of a substantial amount of the sediment from Swan Lake. The presence of wetlands in the project area that could not be disturbed created additional design constraints. The South Dakota Department of Environment and Natural Resources (SD DENR) stated that the sediment ponds needed to be designed and constructed in accordance with the same specifications as wastewater lagoons.

The E/A Approach
Working within the EPA and SD DENR constraints, E/A laid out the final project using innovative design measures. E/A assisted the Association with the following items: archeological survey of the site, application for temporary Water Rights and Water Quality variances, preparation of 401 and 404 permits, initial topographic surveying and mapping of the site, design of the sediment retention ponds, installation of riprap on the lake shoreline, and development of a sediment pond reclamation plan. The final design consisted of three basins with a total capacity of approximately 400,000 cubic yards of sediment. The detention basins were designed around the wetlands. Final project quantities included: 187,500 cubic yards of excavation, 1,047 lineal feet of PVC and CMP piping, 400 square yards of riprap, and 12 acres of seeding. The sediment basins were constructed for nearly $40,000 under the budgeted estimate. Following the completion of the first basin, a mixture of water and sediment was pumped into the basin by a dredge crew supplied by the South Dakota Lakes and Streams Association. Clear water was then discharged back into the lake once the sediment settled out in the basins.

The Outcome
The final project design and completion met the approval of EPA. The Swan Lake Improvement Association implemented a comprehensive four-year restoration plan for dredging sediment from Swan Lake. With the aid of Eisenbraun & Associates, the dedicated members of the Swan Lake Improvement Association provided for the proper restoration of Swan Lake. Such commitment has resulted in a more functional lake for recreation.