11-24-2003 Council Packet - Laserfiche WebLink

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ORONO CITY COUNCIL MEETING MONDAY, NOVEMBER 10,2003 6. Stubbs Bay Water Quality Improvements —MioDebaha Creek Watershed District Moorse stated that Mike Wyatt from the Watershed District would make a presentation on a diagnostic study done on Stubbs Bay. He was joined by Scott Thomas, Watershed District Board Manager, and John Key, District Engineer. Wyatt stated that several members of the community approached the Watershed District Board in the mid I990’s with concerns about the water quality in Stubbs Bay. The MCWD allocated approximately $750,000 to a Stubbs Bay water quality improvement project. They recently completed a diagnostic study, and the next step would be to complete a feasibility study. Wyatt stated that lakes in the area are heavily influenced by phosphorus, with a direct relationship between the amount of phosphorus and water clarity. Phosphorus gets into the lake through stormwater runoff and creek inflows, and is also released through internal sources. Stubbs Bay has two inputs; a creek offtake Classen and a large wetland off the Luce Line. There has been an increase in total phosphorus throughout the study period of 1998 - 2002, with water quality being marginal and declining. Key stated that the Stubbs Bay data showed a direct relationship betweeu drops in chlorophyll and rises in clarity. Thomas stated that there is a dependence on flow, that is, wet conditions during a year flush more phosphorus off the land, providing for year to year variations, thus one had to look at the overall trend. Wyatt stated that in the diagnostic study they monitored surface and bottom phosphorus, chlorophyll, and Secchi depth (clarity). The analysis model looked at: external inflow of nutrients, internal loading of nutrients, lake outflow into Maxwell Bay, total and annual phosphorus loads, and water quality response model. They considered if the total phosphorus were reduced, how it would affect total water quality. Any improvements to Stubbs Bay could affect Maxwell Bay as well. From 1997 - 2002, the bay has been highly influenced by the internal loading from the mucky substrate. There’s an increased nutrient load when the bay turns over in the spring and fall. The external loads increase in wetter years (’97, ’01, ’02). White asked if wave runners have much impact. Wyatt stated that he read a study recently published by the North American Lake Management Association that attributed the mixing of water more to wind than prop wash, but a shallower bay would be more influenced than a deep one. Conclusions from the diagnostic study showed a high degree of internal loading. Stubbs Bay is one of the highest internally loaded water bodies within the watershed district. 8 of 16 1 J