03-21-2023 Council Packet - Laserfiche WebLink

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MINUTES OF THE ORONO CITY COUNCIL MEETING March 13, 2023 6:00 o’clock p.m. _____________________________________________________________________________________ Page 10 of 21 letter states the design option to add height to the existing sixth wall was done on December 9, 2022. But there are no details in this information packet to support the design analysis. Also, this letter states that adding height to the existing sixth wall is I quote, a good option to reduce the steepness of the slope. However, this conclusion to me seems rather vague, and it does not indicate the total gradient and how to mitigate the effects of a steep slope. The letter also states that adding height to the sixth wall versus building a seventh wall, could, I quote, result in less soil disturbance and excavation. However, the bluff has already been disturbed and excavated with a backhoe, basically digging out the entire bluff throughout this retaining wall rebuild project. It is my concern that the Criterium-Schimnowski engineer does not provide any details of how to mitigate the slope from the neighboring properties with respect to adding 1.7 feet of height to the sixth wall, and how that is comparable to building the seventh wall that was in the original plans. But all is explained if you review the original plans of the retaining wall by this engineer, dated August 24, 2022. In the design limitations section, there is a statement, quote, site layout and grading design are not included in wall design services. Those services are the responsibility of the site civil engineer end quote. So that begs the question, who is the civil engineer on this project that can assure that the grading is done properly, to mitigate the bluff grading to adjacent properties? Based on the property surveys, the elevation level of my adjacent property near the very top of the bluff is at 963 feet. The survey in Council Exhibit A depicts the current top of the sixth wall at 957 feet foot elevation, a difference of six feet. By adding 1.7 feet to the sixth wall, the resulting elevation gradient would be 4.3 feet. There is a photo on page 26 of this information packet that does show the existing slope of the property to my property that currently exists. The plans provided in this information packet Council Exhibit E show plants and flowers that will be planted in this area. This depiction also shows a wall on both the west and east side of the property. I am not certain if these walls are the existing wood timber walls that run along the side property lines or some other wall that will be built to replace the wooden timbers. However, my concern is will this depiction in Exhibit E be sufficient to mitigate the 4.3 foot slope differential that currently would exist? As a comparison reference, there are photos included in the letter from Criterium-Schimnowski Engineers dated November 18, 2022 regarding the timber retaining wall upper tier, and that closely resembles the current condition of the bluff with the exception of the snow on the ground. The photo had an outline superimposed for the placement of the seventh timber wall. The outline on the seventh wall did extend along the adjacent property lines to hold back the dirt. The engineer stated in this letter that the final seventh wall height will increase to about four feet tall near each end where the existing slope increases. And a follow-up letter dated November 22, 2022, the engineer states that quote, the slopes of the top of the timber retaining walls constructed to date are much steeper than originally designed. Thus again, my concerns of the steep slopes. The City Council has a very difficult task to decide on the next course of action or reaction for this after-the-fact variance request. The request to increase the height of the top sixth wall to reach the correct grade height rather than installing an additional wall has my concerns. As the property owner on the west side, the elevation gradient to the top of the bluff seems quite steep with regard to adding only 1.7 feet to the top of the sixth retaining wall. Should the City Council authorize construction of the added heights to the sixth wall, I would request that the City Council approval would require an as-built survey following completion of the walls and restoration of the grades. This could be ambiguous considering the top of the bluff and the side elevation grading to the adjacent properties have been altered from the original grades. That is before the fire occurred on the bluff and burned the original retaining walls. I would also ask the City Council to require that containment measures must be implemented to compensate for the change in elevation from the applicant’s property to the adjacent east and west properties such that erosion is mitigated and controlled.