Agenda - Planning Commission - 02/02/2017

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Figures 7 and 8 show examples of properties that are in the bluff impact zone (BIZ) and would thus be regulated under the proposed rules. Figure 7 shows structures built on the top of the bluff overlooking the river corridor. Figure 8 shows structures built into the toe of the bluff. In these areas, bluffward expansion and future vegetation and land alteration activities would need to conform to the proposed rules. Figure 7: Existing structures near top of bluff under proposed bluff definition. Figure 8: Existing structures near bottom of bluff under proposed bluff definition. Rule Proposal The proposed rules provide a uniform set of specific bluff and bluff related definitions to insure consistent and equitable treatment of development across the MRCCA. The definitions also allow bluff features to be easily mapped by local governments using widely available mapping software. The DNR has developed a bluff mapping tool that can be used by local governments with ArcMap, a GIS mapping software, to map defined bluff features within their communities. The proposed bluff definition retains the 18 percent slope criterion established in Executive Order 79- 19, but adds additional parameters to ensure that bluff complexes, rather than isolated slopes, are protected: Proposed Minn. R. 6106.0050, subp. 10 defines a bluff as a natural topographic feature having either of the following characteristics: A. a slope that rises at least 25 feet above the ordinary high water level or toe of the slope to the top of the slope; and the grade of the slope from the ordinary high water level or toe of the slope to the top of the slope averages 18 percent or greater, measured over a horizontal distance of 25 feet; or B. a natural escarpment or cliff with a slope that rises at least 10 feet above the ordinary high water level or toe of the slope to the top of the slope with an average slope of 100% or greater. 26