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HomeMy WebLinkAboutCarol Price 031320231 Date: 13 March 2023 Subject: #LA22-000068, Valdes Lawn Care and Snow Removal LLC o/b/o Mark and Lisa Thostenson 2815 Casco Point Road After -the -fact Setback Variances Public Hearing Other Previous Documents • Original Plans of the retaining wall by Criterium-Schimnowski, dated August 24, 2022 • Council Exhibit D: Criterium Schimnowski Engineers, Letter Dated February 24, 2023 • Letter from Schimnowski Criterium Engineers dated November 18, 2022 regarding emergency request to build 7th retaining wall. Hello Melanie, After reviewing the packet of information regarding agenda item #LA22-000068, dated 03/13/2023, please see my concerns that may be of interest for the City Council Members. Six Retaining Walls versus Seven Retaining Walls My concern is that the adding 1.7 feet to the top of the 6th wall is not sufficient to prevent soil erosion from my property on the west side due to the differences in elevation levels as the retaining walls are currently built. Here are my findings. The letter from Criterium-Schimnowski Engineers (dated Feb. 24, 2023) regarding a 6th wall versus a 7th wall does not mention the change in property gradients to the adjacent properties. The letter states that a design option to add height to the existing 6th wall was done on December 9, 2022, but there are no details in this packet of information to support this design analysis. Also, this letter states that adding height to the existing 6th wall is "a good option to reduce the steepness of the slope". However, this conclusion is rather vague and 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 6th wall versus building a 7th wall "could result in less soil disturbance and excavation. However, the bluff has already been very disturbed and excavated with a backhoe 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 6th wall and how that is comparable to building the 7th wall that was in the original plans. But all that is explained if you review the Original Plans of the retaining wall by Criterium- Schimnowski, dated August 24, 2022. In the Design Limitations section, there is the statement, "Site Layout and grading design are not included in wall design services. Those services are the responsibility of the site civil engineer." 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 top of the bluff is 963 feet. The survey in Council Exhibit A depicts the current top of the 6th wall at a 957 foot elevation, a difference of 6 feet. By adding 1.7 feet to the 6th wall, the resulting elevation gradient would be 4.3 feet. (963 - (957 + 1.7)). Photos • The photo on page 26 of this information packet does show the existing slope of the 2815 property to my 2813 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 wooden 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 feet in slope differential. • As a comparison reference, the photos included in the letter from Schimnowski Criterium Engineers dated November 18, 2022 (regarding the "Timber Retaining Wall Upper Tier") closely resemble the current condition of the bluff with the exception of snow on the ground. The photo had an outline superimposed for the placement of the 7th timber wall. The outline of the 7th wall did extend along the adjacent property lines to hold back the dirt. The engineer stated in this letter that the final 7th wall height "will increase to about 4-feet tall near each end where existing slopes increase." In a follow-up letter dated Nov. 22, 2022, the engineer states that "The slopes at the top of the timber retaining walls constructed to -date are much steeper than originally designed." Thus; once again, my concerns of the steep slopes. Summary 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. This request to increase the height of the top 6th 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 1.7 feet to the top of the 6th retaining wall. Should the City Council authorize construction of the added height to the 6th wall, I would request that Item "b" of the Council Action Requests stating that City Council approval would require a "submittal of an as -built survey following completion of the walls and restoration of the grades" be followed and checked for compliance. Since the "restoration of the grades" could be ambiguous considering that the top of the bluff and the side elevation grading to the adjacent properties have been altered from the original grades i.e., 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. Since the licensed engineer who designed the retaining walls is not responsible for the site layout and gradient services, I would request that the site civil engineer provide the written assurances that the work was completed based on known industry specifications and building codes for mitigating soil erosion and collapse of slopes.