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Prepared by: Bolton & Menk, Inc. PROPOSED IMPROVEMENTS 2026 PMP Street & Utility Improvements ǀ 25X.137753 Page 7 within the project pavement areas to final grade to provide a smooth/drivable street surface in conjunction with the street resurfacing portion of the project. Some damaged valve box tops may require replacement. Hydrant replacements will include the associated gate valve and lead. Existing curb stop boxes identified to be buried or significantly sticking up above the surrounding ground level will be adjusted to the proper ground level. A few curb stops that were not located by city staff will have exploratory excavations completed as part of the project in an effort to locate them or replace them further upstream on the service line to be accessible. See Figure 5 and Figure 6 in Appendix A for the proposed utility improvements. Storm Sewer Based on the existing storm sewer age, size, and performance, the existing storm sewer was found to be in generally good condition. Storm sewer improvements will include rehabilitations at select locations including CIPP lining, minor pipe replacement, select structure replacements, and riprap rehabilitations at select outlet locations. Some of the work identified will be taking place outside of the roadway area in easements that may necessitate tree removal and restoration of temporary access impacts, including private landscaping facilities in some areas. Stormwater quality improvements will also be implemented to help remove sediments and pollutant loads from entering Karth Lake. This will include the replacement of the last storm sewer structure in the street prior to its outfall into Karth Lake, where an existing grit chamber does not exist. This structure will be replaced with a new structure that includes a sump and SAFL Baffle to capture sediment from continuing downstream. This will allow city maintenance staff to easily access the structure and vac out accumulated sediment. Beyond the work identified above, the remaining storm sewer manhole castings within the pavement of the project areas will be adjusted to final grade to provide a smooth/drivable street surface in conjunction with the street resurfacing portion of the project. Some damaged castings may require replacement (assuming 50%). This work will include the replacement of all concrete adjustment rings for each applicable manhole structure within the pavement limits. Additionally, “painted on” internal chimney seals will be installed to mitigate deterioration of the concrete adjusting rings and mortar to reduce the need for long term maintenance. Catch basins within the existing concrete curb and gutter will not be adjusted, unless otherwise identified for structure replacement or curb replacement surrounding the structure. See Figure 5 and Figure 6 in Appendix A for the proposed utility improvements. 1. Risk Assessment of Submerged Culverts in Karth Lake A bathymetric survey was performed in April 2025 to assess the sediment load near the five submerged outlets to Karth Lake. The survey found some organic sediment was accumulating near the outlets, but the majority of sediment is being pushed out further into the lake and forming sediment deltas. These deltas do not negatively affect the performance of the submerged inlets. There was a noticeable ‘hard-bottom’ at each outlet location assumed to be a mix of gravel and rock erosion delivered by the storm outlets. However, the limits of the sediment deltas relative to the ‘hard- bottom’ of Karth Lake’s natural lakebed is difficult to delineate. The outlets likely deliver suspended solids and particulates to Karth Lake without creating a clogging issue. Each inlet is clear of sediment and debris and has a free outfall condition. The four of the five outlet pipes to Karth Lake are submerged and fully below the DRAFT