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ensuing years, while in and of themselves not that dramatic, have served to stabilize this improved condition. Tlus explanation is consistent with the shallow lake bouus (Appendix xx). Another indication drat Lake Owasso benefits from the shallow lake bonus is the fact that there is less algae in Lake Owasso than expected based on the known patterns in other lakes. Normally, as lake phosphorus concentrations increase, the amount of algae increases in turn. This is a predictable pattern. A model' has been developed that is used to predict algae abundance (as measured by chlorophyll) from a lake's phosphorus concentration. By examining the actual phosphorus and chlorophyll measurement from recent years, we see that the amount of algae growth in Lake Owasso is less than other metro lakes with similar levels of phosphorus (see table below): Year Phosphorus Measured CLA Predicted' CLA 1999 32 5 18 1998 22 5 12 1997 40 13 22 1996 33 10 18 1995 35 11 19 1994 48 11 27 1993 44 13 24 1992 47 13 26 1991 53 16 30 1990 56 13 31 1989 48 10 27 1988 62 15 35 [Note: There was some concern expressed by the Lake Owasso Association Executive Committee about the promotion of the shallow lake theory and the conclusion that the Snail Lake experience shows this to be a workable solution. To clarify, the Snail Lake experience is presented to show that there are other shallow lakes where algae is reduced and there is clear water in association with abundant native plants. The conclusion that the plant protection approach is `workable' for Snail Lake is in reference to the fact that the Snail Lake Association, when given this option, agreed it was the best option for their lake. While this is also an option for Lake Owasso, this is not meant to imply that it is the best or most workable option for Lake Owasso.] Aquatic Plants Aquatic plants have been evaluated periodically by DNR field crews or by Ramsey County Public Works. The plant surveys were conducted using different field methods and at different times during the summer. This summary lists which species were present, and omits details regarding the distribution of plants around the lake. Aquatic Plant Survey Summaries -Lake Owasso 9/48 8/55 6/81 6/84 5/90 6/90 6/91 Submerged plants species Largeleaf pondweed P P P P P Potamogeton atnplifolius Curlyleaf pondweed * * P P P P P Potamogeton crispus Variable-leaf pondweed P Potamogeton gramineus