09-18-1995 Planning Commission Minutes

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u • MINUTES OF THE ORONO PLANNING COMN41SSION MEETING HELD ON SEPTEMBER 18, 1995 ( #5 - #2059 Minnehaha Creek Watershed District - Continued) The project has been in the planning stages for the past couple years and is slated to be constructed early 1998. The project will be done in the beginning of January to the beginning of February with revegetation and replanting taking place in the spring. Peterson clarified that the project would only occur and be effective if the Deerhill project in Medina is completed. Tom LaBounty said the Medina project is in condemnation process at this time. He noted that the easements for the other two ponds, one in Long Lake park and the other on the private land, have been completed. The object of the Long Lake project is to clean up the water discharging from Long Lake to Lake Minnetonka to the corridor to the Mississippi and is part of the overall scheme. Schroeder asked if there was anything that would prevent the Deerhill project from being completed. LaBounty said he expects an appeal to the condemnation proceeding but expects to have all the permits in hand by the end of September. LaBounty cited the Gleason Lake project and the concerns regarding the disposal of materials from the site on Hwy 12. He would like to address the problems relating to this project. LaBounty said contractual agreements have been made with the property owners when asked by Smith. Performance stipulations have been set out. The alum treatment of Long Lake will occur after the ponds are completed. The effectiveness of the treatment will depend on how effective the ponds are and their construction. LaBounty said alot of the effectiveness depends on the Best Management Practices in the sub - watershed. The clarity level would be a progressive improvement. 5 +' is expected, which is a radical difference from the 1' clarity presently in Long Lake. When the revegetation is ocurring, the improvement in clarity will hit a flat spot, but will then continue to improve. Hawn asked about the sediment ponds. She was informed that 50% of the phosphorus would be removed by the alum treatment. Hawn questioned whether the remaining 50% would contribute to future water quality problems being created. Syverson noted that while the phosphorus removal was believed to be 50 %, the sediment removal would be a higher percentage, 80 -90 %. This would result in a significant decrease of sediment to cover the alum. 50% is the typical efficiency found according to Syverson. Further gains would require more ponds and would be too large to be feasible. Syverson said the process is two fold. The internal process would recycle the alum which would be taken out and sealed and then more taken out from there resulting in a higher percentage of 75 %. Reestablishing vegetation then gives the lake a chance to work on its own. The project is a helping hand which allows the lake to work on its own. 12