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X City of Arden Hills Page 9 of 63 October 7, 2022 Other design considerations such as exact horizontal and vertical alignments, geometric design requirements, and horizontal clearances are not able to be determined without completing a topographic field survey, and these details will need to be evaluated and included in the final design phase of the project. If the trail is constructed immediately adjacent to the roadway, the trail’s horizontal and vertical alignments would exactly match those of the roadway. The timing of the trail construction will be best accomplished when the adjacent roadway is reconstructed, and this applies especially to this portion of the proposed trail remaining to be constructed as it may be reconstructed as an urban section instead of as a rural section and the trail design can be adjusted to match the proposed roadway. It is recommended to consult the MnDOT Bicycle Facility Design Manual thoroughly during the design phase of the project for guidance on additional design considerations beyond the scope of this feasibility study, including vertical clearance, cross slope, grade, pavement markings, drainage, surfacing material, lighting, personal safety, controlling motor vehicle access, ADA requirements, and path intersections with side roads, driveways, and sidewalks. Lastly, it should be noted that except for the portion from Lakeshore Pl. north to County State Aid Highway 96, the portions of the trail that have previously been constructed appear to be 10’-wide sidepaths up against the back of curb. Locating a 10-wide sidepath against the back of curb reduces the operating width to about 8.5’ due to a user’s inclination to shy away from the edge of the curb. There are also some portions with retaining walls and chain link fence, which produce a similar effect and result in an operating width reduction of two feet due to a user’s inclination to shy away from them. While operating widths less than ten feet are acceptable for constrained areas, it is recommended that the design of the remaining portion of the proposed trail improvements allow for the full preferred ten foot minimum operating width for sidepaths. If locating the sidepath up against the back of curb, this can be accomplished by, for example, paving a 12’-wide sidepath up against the back of curb and increasing that to 14’-wide when in areas constrained by fence or safety rail on the outside. 3.3 OTHER CONSIDERATIONS Stormwater management considerations are being emphasized more than ever by regulatory agencies. This project falls within the jurisdictions of Minnesota Pollution Control Agency (MPCA) and the Rice Creek Watershed District (RCWD). Currently, RCWD allows an exception to their stormwater management requirements for sidewalks and trails ten feet wide or less that are bordered down-gradient by vegetated open space or vegetated filter strip with a minimum width of five feet. In any area where the project does not meet these criteria, that portion of the trail will be required to meet the RCWD stormwater management requirements and an RCWD stormwater management permit will be needed. Again, it should be noted that the portions of the trail that have previously been constructed appear to be 10’-wide sidepaths up against the back of curb. If this design were used for the portion of the proposed trail remaining to be constructed, because of the lack of a vegetated buffer strip at least 5’-wide between the sidepath and the curb, RCWD stormwater management requirements would apply unless the surface of the path were sloping away from the curb and through a vegetated buffer strip at least 5’-wide. Note that if a paved path width of more than ten feet were used, as recommended if locating the sidepath up against the back of curb to allow for the full preferred ten foot minimum operating width for sidepaths, the project would need to meet the RCWD stormwater management requirements regardless of which direction the surface of the path were sloping.