Using Conservation Drainage to Reduce Ravine Sedimentation in Seven Mile Creek
This project aims to significantly reduce the amount of sediment transfer from eroding bluff areas to Seven Mile Creek during spring snowmelt and rain events throughout the year. This will be accomplished by installing and maintaining drop structures and reinforcing the existing spalsh pool at the outlet pipe without destabilizing the surrounding bluffs. When applied in tandem, this project will reduce the peak flow rate to ravine areas while shielding and protecting the bluff itself from eroding.
At the same time, the splash pool will dissipate water energy at the base of the water fall area allowing water to flow with less energy to the lower part of the stream. Upland conservation practices will be implemented to retain water on the land. These types of conservation practices have proven to reduce sediment, phosphorus and in some instances nitrogen. In addition, subsequent monitoring will take place to demonstrate the effectiveness of combining all practices within an entire stream system.
The 20-member BWSR board consists of representatives of local and state government agencies and citizens. Members are appointed by the governor of the state of Minnesota consistent with Minnesota Statutes 103B.101. Board members at the time the grant was made were: County Commissioner Appointees: Quentin Fairbanks; Tom Loveall; Brian Napstad; Soil and Water Conservation District Appointees: Paul Langseth, Louise Smallidge and Bob Burandt; Watershed District or Watershed Management Organization Appointees: Gene Tiedemann, LuAnn Tolliver and Todd Foster; Citizen Appointees: Paul Brutlag ; Gerald Van Amburg; John Meyer; Cities & Townships: Sandy Hooker -Township; Christy Jo Fogarty -Metro City; Keith Mykleseth -Non-Metro City; Agency: Chris Elvrum - Minnesota Department of Health; Rebecca Flood - Pollution Control Agency; Tom Landwehr - Department of Natural Resources; Matt Wohlman - Minnesota Department of Agriculture; Faye Sleeper - Minnesota Extension Service;
Bill Thompson - MPCA Project Manager and Research Scientist; Sonia Maassel Jacobsen - Hydraulic Engineer, NRCS; Bruce Henningsgaard - Principal Engineer; William P Anderson - Principal Engineer; Greg Eggers - Drainage Engineer, MN DNR; Jim Solstad - Hydrologist 3; Allan M. Kean - Chief Engineer, BWSR; Adam Birr - Impaired Waters Technical Coordinator;
Nicole Clapp
(d) $1,000,000 the first year and $1,000,000 the second year are for technical assistance and grants for the conservation drainage program in consultation with the Drainage Work Group, created under Minnesota Statutes, section 103B.101, subdivision 13, that consists of projects to retrofit existing drainage systems with water quality improvement practices, evaluate outcomes, and provide outreach to landowners, public drainage authorities, drainage engineers and contractors, and others.
Project Outputs:Reduced sediment delivery to lower portion of 7 mile creek originating at ravine drop (waterfall) portion of the waterway. - 7 Mile creek and the Lower Minnesota River Reduced rate flow peaks to lower 7 mile creek during rain events - 7 Mile creek and the Lower Minnesota River Proposed Reductions:3,500 lbs/year Phosphorus 15 tons/year Sediment
A substantial reduction in sediment delivery was achieved through this project by installing one erosion control structure, one grade stabilization structure and one grassed waterway. Peak flow was reduced through a drainage water management plan and in the installation of 20 water control structures, designed to reduce the overall amount of water leaving a site throughout the year. Overall, 20 tons of sediment, 20 pounds of phosphorus and 800 pounds of nitrogen are being reduced annually.
The source of additional funds varies from project to project, but generally consists of federal, local and non-public sources.