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Project Understanding and Approach Snelling Avenue North Street and Utility Improvements | City of Arden Hills These roadway geometrics meet MSA standards for a reconstructed roadway. While we see value in confirming the project typical section with state aid staff, we see no need for a variance from MSA standards to achieve project goals. In the event MSA staff suggests a variance is necessary, Bolton & Menk is experienced with securing such variances through presentation to the Municipal Screening Board. In this case, a variance from meeting reconstruction standards with a request to instead fall back to less demanding roadway rehabilitation standards clearly appears warranted. In consideration of a variance, one must demonstrate a practical difficulty—a threshold which is clear in this case. The feasibility report clearly demonstrates a practical difficulty with traditional full depth reconstruction of the roadway corridor due to the presence of contaminated soils—soils which were apparently contaminated when the roadway was under a separate jurisdiction. Our proposed solution intends to reclaim the roadway to 12-inch depth as proposed under feasibility report alternative #2, so as not to expose the underlying subgrade. Subgrade exposure will be proposed to be limited to less than 10,000 square feet to avoid triggering RCWD's stormwater management requirements. Assuming a 20-foot-wide utility trench, this would imply the project will be limited to 500 LF of utility trench to remain under before costly and spacious stormwater management measures are necessary. • To remain under 500 LF of open utility trench and to avoid additional exposure of similarly costly contaminated soils, Bolton & Menk will propose trenchless replacement of the identified watermain segment with the only trench excavations being for drilling and connection pits. We estimate these 50-foot x 20- foot pits to require only 1,000 square feet out of the allotted 10,000 square feet threshold. • Regarding the drainage improvements needed to facilitate drainage from the curb, we have two proposed strategies that will be evaluated: »If the trail is installed on the east side: from our site visit, we noted a ‘quarter crown’ on the east side of the road where both drive lanes flow to the west and only the shoulder flows to the east. In this area, it would be conceivable to install a ‘tip out’ curb to avoid requiring catch basins or storm sewer. »In areas where storm sewer is required: a catch basin would be installed along with pipe to discharge the storm sewer to the adjacent existing ditch (perpendicular to the roadway). The ditches will continue to accept the same runoff as the existing conditions. Following confirmation of state aid rules being met, we intend to meet with the RCWD to confirm application of its rules to our proposed project approach. Following confirmation of a workable project scope with the MSA office and RCWD while also working with city staff, Bolton & Menk would inform the city council of the findings at a work session. Based on any feedback at that work session, final design would commence toward implementation of a solution in 2022 on schedule and as intended. The above scope of services has been built into our Task 1 and Task 4 proposed efforts. It will serve as the basis for our proposed project plan and specification efforts scoped in Tasks 5 and 6. 7 1. Two, 11-foot drive lanes. Motorist speed was presented as a concern by the public. Studies have shown motorist speed more tied to road width and environmental characteristics than posted speed limit. While measures like a speed study and dynamic speed signage might be beneficial to some degree, a reduction in lane width to 11-feet would be more beneficial to address the concerns. 2. 8-foot bituminous walk (trail) on the east or west side of the roadway. While it may seem like semantics, it is noted that bituminous walks have less stringent requirements than ‘trails’ or ‘share use paths,’ as walks do not require compliance with state aid trail design standards or MN statue 8820.9995. We recommend a bituminous walk in this case, which may be functionally used by pedestrian and cycling families. 3. B618 concrete curb and gutter on the trail side of the roadway only. This will separate the trail from the roadway, with trail directly adjacent to back of curb. 4. 6-foot shoulder on the non-trail side of the road, as measured from outside the 11-foot drive lane to the bituminous pavement edge. 5. 2-foot curb reaction zone (shoulder) on the trail side, as measured from the outside of the 11-foot drive lane to the face of the installed curb to meet MN Statute 8820.9936. 6. A total proposed roadway footprint of 38.67 feet, which is a reduction of 1.33 feet as compared to the existing approximate 40-foot width identified in the feasibility report. The reduction in width would be used to raise the roadway profile to minimize the volume of reclaimed material to be hauled out and/or used to minimize impacts to the adjacent ditch slopes. Proposed Typical Section