Fountain Lake is a major aquatic resource for the City of Albert Lea and the surrounding region. However, a significant sediment load into the lake caused sedimentation and nutrient deposition—leading to poor water quality, reduced lake use, and fish kills. The SRRWD retained Barr to conduct a preliminary engineering analysis of lake dredging. The study included an in-depth analysis of water quality to document anticipated changes and improvements resulting from dredging. Sediment-sampling and water-quality-monitoring data helped calibrate a three-dimensional, hydrodynamic sediment-transport and water-quality model (Delft3D), which was used to evaluate and understand lake-water-quality management options.
As part of the study, Barr developed dredge prisms (sediment removal plans) based on phosphorus content. We also evaluated sediment dewatering, dredged-material disposal and reuse options, and the likely effects of dredging on lake water quality. Modeling results indicated that the internal bed load was a significant source of phosphorus—up to 81 percent of the lake’s growing-season total phosphorus budget. Therefore, sediment dredging was identified as the primary management tool for improving the lake’s water quality and habitat, enhancing fisheries, and increasing public use.
Coordination with multiple municipal, county, regional, state, and federal stakeholders was a key component of Barr’s work. The district completed final design and permitting and began hydraulically dredging Fountain Lake in 2018. Barr also helped the district obtain grant funding and assisted with environmental review and permitting.