Osage Reservoir Restoration Project

Location: Osage City, Kan.

Client: City of Osage City

Completion Date: Ongoing

Burns & McDonnell prepared a lake restoration feasibility study that consisted of investigating the physical, chemical and biological components of the Osage City Reservoir, the main drinking water source for the City of Osage City, Kan. The study also evaluated lake restoration alternatives; developed construction cost estimates and schedules; and designed a conceptual plan to restore the reservoir to 90 percent of the original design capacity.

The investigation consisted of completing a bathymetric survey to determine water and sediment thickness; laboratory analysis of the sediment and water, and a land use assessment within the watershed. The restoration alternatives were limited to mechanical and hydraulic dredging and aeration treatment systems based on the meeting the budgetary requirements of $1.135 million and minimizing environmental impacts. The conceptual design consists of removing approximately 49,000 cubic yards from the inlet; 50,000 cubic yards from the middle and 75,000 cubic yards from the main body.

Burns & McDonnell was retained by the City of Osage City to prepare and submit a State Conservation Commission Restoration of Public Water Supply Lakes Grant application to the Kansas Department of Agriculture Division of Conservation to restore the design capacity and increase water quality of Osage City Reservoir. The City of Osage City was awarded $1.135 million to restore the reservoir to its original water supply design capacity.
Currently, Burns & McDonnell is performing the engineering and design and environmental permitting followed by completing the front end bid package information and assisting with the selection of the contractor. In addition, Burns & McDonnell will oversee the lake restoration efforts.

  • Grant writing
  • Bathymetric and sediment thickness mapping
  • Sediment and water collection
  • Laboratory analysis
  • Evaluation of dredging alternatives
  • Land use assessment
  • Aquatic habitat and fisheries assessment
  • Engineering and design
  • Cost estimating and scheduling
  • Public involvement
  • Environmental permitting (Section 401 and 404, NPDES, water use)
  • Construction monitoring
  • Agency consultation

The Osage City Reservoir is a 52-acre lake within a 3,100 acre watershed, which was designed and constructed in 1913 on an unnamed tributary to Salt Creek as the main source drinking water for the City of Osage City. The reservoir has historically filled with sediment, requiring the modification of the dam and spillway over the years to increase the water capacity. In 1954, approximately 160,000 cubic yards of sediment was removed increasing the capacity from approximately 650,000 cubic yards to more than 800,000 cubic yards. Currently the reservoir is used as a supplemental water supply source, due to the growth of the service area over the past 50 years. Over the past 58 years the reservoir has lost more than a third of its total design capacity to sediment loading and decreased water quality, allowing the reservoir to become hypereutrophic. Therefore sediment removal and development of a long-term watershed management plan needed to be developed and implemented.