04-17-2017 Planning Commission Packet

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16-3883 April 17,2017 Page 4 of 7 For Lot 2, topography and the location (and maintenance needs) of the existing municipal sewer lines are complicating factors. The municipal sewer installed in 1973 crosses the property from north to south. See Exhibits C &D. The sewer lines consist of a gravity line flowing from south to north across the site, discharging to a lift station at the very north end of the property at the shore, which in turn pumps into a parallel forcemain that runs back up the hill adjacent to the gravity line, discharging to a manhole in Windjammer Lane. The easement for that sewer line pair is 20' wide,and no structures can be built over that easement. The impact is that the proposed house location for Lot 2 is restricted to the area between the sewer easement and the 75' setback,with little flexibility for shifting the house. To make matters worse, the actual vehicle route used by the Public Works Department follows the dashed line on Exhibit C for maintenance of the lift station, due to the topography. It is necessary on a regular basis to bring a truck down to the lift station for maintenance, and there is no other way to access the lift station. The City needs to preserve this non-easement route for future sewer system maintenance. The 40'x80' "possible house" site depicted on Lot 2 is virtually the only area of Lot 2 that is a desirable house location under the proposed subdivision layout; but also consider that it is likely a house at this will be expected to have decks, patios, and a walkout configuration. City code will disallow any grading or filling within the 75' zone, and there is barely 5 feet of elevation change from the 75' line to the sewer easement. All of these factors dictate the need for careful and creative house design for Lot 2. Lot 3 contains the existing house,built in 1956 according to tax records. Replacing the house will likely require it to move back from the lake some distance, as the 75' setback line appears to run through the east side of the structure. With or without the proposed subdivision, an average lakeshore setback variance would be required for replacement of this house, again suggesting that this should be addressed as part of the plat approval process. Road Layout and Standards An initial question for discussion was whether the road serving the proposed 3-lot development should be public or private. During the sketch plan review it was indicated by the developer that a private road would be most appropriate, and that is what is proposed. Although only a small number of homes will be served, the City code requires for 3-6 lots a road of 24' paved width in a 50' road corridor, ending in a 100' diameter cul-de-sac with 80' paved width. The road access onto North Arm Drive is at the outside of a curve, and would not be expected to have any sight-distance concerns. At slightly less than 300 feet in length the cul-de-sac meets the City's 1000-foot maximum length limitation. It is unknown at this time whether curb and gutter would be required in order to manage stormwater runoff. Preliminary street design and grading information will be reviewed by the City Engineer prior to the preliminary plat review by the City Council. The proposed cul-de-sac location abuts the rear yard of the existing residence at 835 Windjammer Lane. While those owners and their predecessors have experienced a single private driveway at that location since the house at 835 was built in 1969, the driveway at 800 North Arm has existed at its current location since at least the 1940s or earlier based on available historic airphotos. Conversion of the driveway to a road may have negative impacts to those neighbors,who have not commented on the project as of this writing.Moving the private road further north to provide some buffer might be feasible but would result in less usable street yard area for Lot 1.