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2021-20 Papke (WRC) Memorandum To: MacKenzie Young Walters, Associate Planner From: Matt Unmacht, Water Resources Coordinator CC: Erik Henriksen, Project Engineer, Ryan Pinkalla, Water Resources Technician Charlie Howley, Public Works Director Date: 09/09/2021 Re: Planning Case No. 21-20 – Papke Parcel (Lake Minnewashta Peninsula) BACKGROUND The Water Resources Department has reviewed the Variance submittal for the Papke Property – Lake Minnewashta Peninsula. The applicant is requesting wetland setback variances for a driveway, porches, and a patio, potentially a septic system variance, and requesting the use of wetland buffer averaging. The City’s wetland protection ordinance (Chapter 20, Article 20-VI) states that “Wetlands help maintain water quality, serve to reduce flooding and erosion, act as sources of food and habitat for a variety of fish and wildlife, and are an integral part of the community's natural landscape. Wetlands provide the aesthetic benefits of open space and can be used to provide a natural separation of land uses. It is the intent of this article to establish a policy of sound stewardship through coordination of regulations that conserve, protect, enhance, and result in the no net loss of these environmentally sensitive resources. In addition, it is the intent of the city to promote the restoration of degraded wetlands…The intent of this article is to avoid alteration and destruction of wetlands. When this is not feasible, mitigation must be provided to recreate the function and value of the lost or altered wetlands.” The City’s wetland buffer ordinance exists to protect these wetlands from degradation. Development directly adjacent to a wetland can negatively impact habitat and water quality due to stormwater runoff, erosion, and flooding, among other factors. Due to the important role that these ordinances plays in protecting the quality of the City’s natural resources, the City should take extra caution when reviewing potential wetland and buffer variances. The wetlands on this property discharge directly to Lake Minnewashta. Lake Minnewashta is not listed as impaired for nutrients by the Minnesota Pollution Control Agency, however, intense development in areas that drain to the lake, and especially in areas that are in such close proximity to the lake, could lead to its listing in the future. As such, extra care and review should be undertaken on any project that proposed development that could impact Lake Minnewashta. On April 20, 2021, the applicant submitted a complete wetland delineation report, which identified one wetland on the property. This wetland was classified as combination of wetland types 3/6/2. On May 11, 2021, an on-site TEP review of the wetland delineation was conducted. The TEP review resulted in changes to the wetland boundaries, but not the wetland types. An updated wetland delineation figure was submitted on May 12, 2021 (see photo below, delineation boundary in green). The wetland delineation with this updated wetland boundary was formally approved on May 24, 2021. This approved wetland delineation allowed the developer to determine precisely where the wetland boundary and subsequent wetland buffers and setbacks would be and plan accordingly. This wetland is classified, per the City’s MnRAM database, as a Preserve wetland. This means that this is a high quality wetland and that a permanent buffer, from the edge of the wetland, must be established. This buffer must be 40-feet in width. In addition, principal structures (homes, patios, garages, etc.) must then be set back 40-feet from the buffer edge, and accessory structures (driveway, shed, boathouse, etc.) must be setback 20-feet from the buffer edge. The applicant is proposing to use wetland buffer averaging on this parcel. This means that the total square footage of the required wetland buffer remains the same, but the buffer may not be precisely 40-feet throughout. For example, if the applicant proposed the buffer to be 30 -feet in one location it would need to be 50-feet in another location, so long as the total amount of buffer area remains the same (or more than) the required 40-feet. City of Chanhassen ordinances do not allow for wetland buffer averaging, hence the need for the variance. It appears that the use of wetland buffer averaging is proposed to accommodate the septic system. However, the septic system can still be constructed in its proposed location even without the need to use averaging. Regardless of the City of Chanhassen’s ordinances on wetland buffer averaging, the Minnehaha Creek Watershed District also has rules regarding wetland buffer averaging and approval from the District for the use of averaging would be required prior to any building permit approval. In addition, the applicant is proposing wetland buffer setback variances for various aspects of the home:  Porch A encroaches approximately 13.5-feet into the 40-foot principal structure setback  Porch B encroaches approximately 12-feet into the 40-foot principal structure setback  Patio encroaches approximately 16-feet into the 40-foot principal structure setback All three of the above items would require a wetland buffer setback variance. However, all three of these items are necessitated as a result of design choices rather than any specific constraining features of the property. It appears that it is possible to propose a smaller home on this site that would not require these three variances and would not require the need for wetland buffer averaging. Doing so would still allow reasonable use of the property while also best protecting the sensitive natural resources of this parcel. The applicant is requesting a variance to construct a driveway where the current access road exists. Per the City Code, a driveway would be required to be setback a minimum 60-feet from the wetland buffer edge (40-foot wetland buffer plus 20-foot accessory structure setback). There is no feasible way to construct a driveway at this location that would conform to these required setbacks. The applicant has shown a willingness to decrease the size of the driveway from initial plans. As such, it is the opinion of the Water Resources department that a variance for the driveway should be granted. CONCLUSION/RECOMMENDATION The proposed project poses risks to the wetlands, wetland buffers, and the overall health of Lake Minnewashta. The Water Resources department understands that due to the location of this parcel, development is nearly impossible without some impacts to sensitive natural resources. However, based on the submitted plans, it appears that the proposed home goes beyond what is necessary to construct a home of reasonable use and thus posing unnecessary risks to the natural resources on the parcel. It appears that there is a smaller home pad available that would allow reasonable use of the property while negating the need for wetland buffer averaging and the wetland buffer structure setbacks. As such, the Water Resources department recommends denial of the variances for the use of wetland buffer averaging and wetland buffer setbacks relating to the home. However, due to the site constraints relating to the driveway, the Water Resources department recommends approval of the variances for the construction of the driveway.