11-10-2003 Council Minutes - Laserfiche WebLink

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ORONO CITY COUNCIL MEETING MONDAY, NOVEMBER 10, 2003 (6. Stubbs Bay Water Quality Improvements Minnehaha Creek Watershed District, • Continued) study that identified an area from Classen Lake that inflows into the bay and is highly erodable. That area could be helped by some kind of stabilization project. Such a project may or may not be included, depending on how they want to manage to the bay as a whole. Murphy asked where phosphorus comes from, other than fertilizer. Wyatt stated that the external load comes from anything that gets washed into the lake, both organic and mineral material. Murphy asked if the macro - solution is to scrub the water on its way to the bay. Wyatt replied that they have used stormwater ponds to allow sediment to settle out before reaching the lake, and that has been successful in reducing the external nutrient load. Murphy stated that the MCWD is requiring a 25' buffer around wetlands. Wyatt stated they require from 16 !/2' -35'. Murphy asked if that was to try and scrub water before it reaches the wetlands. Wyatt stated that the purpose is to provide some type of treatment for runoff before it reaches the water bodies. McMillan stated that as she understands the report, the main problem in Stubbs Bay is the internal loading, which can't be scrubbed out and is tougher to control. She stated she is • familiar with the Long Lake alum treatment and is not sold on its results. Wyatt stated that one way to treat the internal loading is through alum, another is through ferum chloride, or using some sort of aeration system. The aeration would settle out the phosphorus and keep it attached to the bottom, where it can't feed the algae growth. Thomas stated that Stubbs Bay would never be clear. They could remove a lot of phosphorus without seeing much benefit. The problem is that the bay will continue to get worse. Doing nothing is not an option, because the external loads will continue to increase. One thing they can do is deal with the land use plans to minimize the impact of future development. Sansevere asked what would be the best course of action. Wyatt stated that the feasibility study and stakeholders meeting would determine what kind of work they do. Sansevere asked what the most likely scenario would be. Wyatt stated they would likely be able to treat the internal load with aeration and alum or ferum chloride; and manage the external load by controlling runoff. The alum treatment would need to be repeated, so they would have to do a long -term study to determine how often they'd have to repeat the process. They have not done an aeration project yet. 10 of 16