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frequent algal blooms occurred in the lake. The MPCA suggests a TSI value on the order of 60 as an upper limit for achieving swimmable use in this region of the state. This is also ( considered the upper limit for boating activities. The data suggest water quality variations in Long Lake sometimes make the lake suitable for all recreational activities and sometimes make the lake undesirable for swimming and boating activities. Future development in the Long Lake watershed will likely lead to further degradation of Long Lake's water quality. Additional degradation is expected to cause additional conflicts between water quality and usage. The outflow from Long Lake flows into Lake DeMontreville, and is a major contributor to Lake DeMontreville's phosphorus load. Therefore, additional phosphorus loading to Long Lake will not only likely degrade Long Lake's water quality, but will also adversely impact the water quality of Lake DeMontreville. Therefore, reduction of existing phosphorus loadings to Long Lake and limitation of increases in future loading may be necessary to protect and/or improve the water quality of Lake DeMontreville. The DNR reports that there are abundant weeds and algae in Long Lake, which they believe to be caused by excessive nutrient loading from stormwater runoff. Residents report that a large sediment delta has formed on the south side of the north basin. The presence of the sediment delta was also noted by the DNR in their 1989 fisheries survey. According to lake residents, the sediment delta has been forming for the past 10 to 20 years, possibly as a result of highway runoff. Residents are concerned that the sediment delta will keep increasing in size. No data are available to determine whether sediment deposition is still occurring. Since the deposited sediment is sand, it is unlikely that the sediment is coming from the ditch on the southwest side of the lake. Any sand in the ditch flow should have settled out in the ditch, prior to entering the lake. 4.2.5.6 VBWD Water Quality Management Goals In Section 3.2 -- Water Quality Management Plan, Long Lake is identified as a Category 11 water body based on its existing water quality and existing and desired recreational uses. Further description of this water quality classification is included in Section 3.2. Because conflicts between the lake's water quality and its recreational usage as a Category II water body sometimes occur, VBWD's goal is to restore Long Lake's water quality to prevent such conflicts. VBWD will complete hydrologic and nutrient budgets for Long Lake under existing and future watershed conditions, depending on availability of funds. Then, using the study results, VBWD will review and possibly revise its management goals for Long Lake. The goals will be based on both the recreational usage of the lake and the impact of the Long Lake discharge on Lake DeMontreville water quality. Assuming highway runoff is the source of the sediment delta on the south side of the lake, VBWD will work with MNDOT to find a solution to the sedimentation problem. One possible solution is to retrofit catch basins/manholes with sumps to trap the sediment. The sediment would then need to be removed on a regular basis. To convert the manholes to sump manholes may require installation of new manholes rather than retrofitting. VBWD does not propose to remove the sediment delta, because of access problems and the anticipated high economic cost. If MNDOT will not cooperate with such a project, VBWD will survey the extent of the sediment delta and re -survey it annually for three years. However, it may be necessary to verify the sediment source before proceeding. To identify the sediment source may require the use of automatic sampling equipment in the two culvertsonthe south side of the lake. A Category lI water body is appropriate for all recreational uses except full body contact activities: sailboating, water skiing, canoeing, wind surfing, jet skiing. 23\82\045\SEC4.RPT\KMH 15 DRAFT: June 23, 1994