3301 SEAWAY BLVD WHOLE SITE 2025-10-30

Comments Thus Far for Review of 3301 Seaway Blvd, Bertch Warehouses (As of 3/14/2017) First comments from City Engineer, Ryan Sass (preliminary): 1. The pond wall setbacks appear to be satisfactory. Pond liner protection, leak detection, and pond maintenance guidelines appear to be lacking. 2. 1 have a couple specific items that will need clarification or correction: The pond outlet pipes in the NW corner of the pond grades do not make sense. The pipe slopes and elevation shown in plan do not agree with the invert elevations shown on the storm drain structure table for CB 28, nor do they agree with the elevations shown in the control structure detail. The outlet pipes leading to the control structure would be retrograde. The northern terminus of the pond wall does not make sense. The plans appear to show the wall tapering to 0.0 in height.at the surface. The wall will need to have some height all the way to its terminal point. I did not do a thorough review of the drainage and conveyance as I am confident Jane will have additional comments, but rather wanted to identify a couple of discrepancies that were apparent to me. 11r at/,:�6 rid". Comments from Third Party Geotechnical Reviewer, HWA: We have reviewed the documents you provided on February 24th associated with the proposed Seaway Center. I general, we do not take exception to Terra Associates analysis or recommendations. However, we did have one comment that we believe merits continued review as the design progresses. With respect to possible leakage through the storm water pond Flexible Membrane Liner we agree with Terra Associates that the presence of the pond liner will reduce the expected water introduced to the steep slope when the liner is not leaking. When the liner is not leaking, we agree that this reduction in water will result in some increase in stability of the slope. In the event that the liner starts to leak, it is likely that the leak/leaks will be concentrated to certain areas and not uniformly distributed across the pond area. We believe that this is an important distinction as an acceptable leakage rate equal to the anticipated precipitation may be valid if the leaks are uniformly distributed across the pond but will likely be problematic when concentrated in certain areas. Given the relatively impermeable nature of the glacial till soils, identified in TP-7 through TP-9, we would expect that any water that leaks from the pond to flow down slope to the location of the proposed cast in place wall. As indicated by Terra and Associates, piping under this wall could cause damage to the proposed wall structure. We recommend that Terra and Associates design to mitigate this occurrence be reviewed when it is developed . We also recommend that their final mitigation design be sized to account for all anticipated leakage from the pond not just leakage near the wall boundary.