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GLWMO MINUTES JANUARY 24, 2008 PAGE 8 above normal in winter. One graph shows treatment efficiency through ponds. Red is low efficiency; green is high. Lake Emily and Lake Judy have high treatment efficiency. Mogg asked if the efficiency of each pond was captured. Sobiech answered, yes. Eckman asked the amount of sediment that was taken from the storm pond near Lake Judy. Sobiech stated that information would be included in the updated models. It would be good to know the amount of material taken from the last cleaning project. Then the accumulation rate could be pro-rated. Sobiech stated that using watershed models, an annual budget for phosphorous was developed for Lake Owasso, as shown on the two pie charts in Figure 12. These are results of in-lake water quality models. The water shed runoff models taken with the in- lake models are calibrated to 2007 data for the southern site and the northern site. The top chart shows that phosphorous is entering the lake from runoff. The bottom chart shows the internal inload of phosphorous coming from two areas--the die-back of curly leaf pond weed and the release of phosphorous from bottom sediment. Ferrington noted that at the southern site almost half the watershed passes through that one culvert. More than half the summer there is no discharge for half the watershed. The discharge percentage for the total watershed is 52%. Mogg stated that he would like to explore the possibility that leaf depositional area is a contributing source at that end of the lake. This has been brought up in previous reports.. Stark stated that if that is true, the yield from that watershed would be higher than the rest of the watershed. Schwartz stated that the watershed splits south of that half from the west. The other half is from the east. Additional samples could be done. Stark requested suggested that outlet by load per acre in that watershed is higher than other watersheds. There is something else going on. Mogg stated that the previous study did point that out. Curly leaf needs to be addressed. He suggested that more samples could be taken this year to get more data and check the data against the models. Sobiech agreed that it may be beneficial to continue to monitor the southern site at County Road C. Stark added Dale Street. Sobiech stated that tasks yet to do include looking again at the calibrations in terms of volume and better assessing how the Lake Owasso outlet is performing. Look at the period from 1995. Look at future land uses. A few small areas are projected to change,