Agenda - Council - 08/23/2022 - Laserfiche WebLink

Home

for both utility installation and street construction, but will need to review the proposed geotechnical report for specific details. Additionally, storm water ponding will be required with the proposed street improvements, and the geotechnical report will assist Staff with pond design. 161 st Avenue was included in the Ground Penetrating Radar (GPR) Pavement Evaluation performed by Braun Intertec. This data provides bituminous and aggregate base thickness information. The GPR data is included in the street segment summary attached to this case. 161 st Avenue is a Municipal State Aid (MSA) street, and must be designed to MSA standards. Staff is proposing to generally leave the street at the current 29-foot width, but replace the bituminous curb with concrete curb and gutter. Staff review has not found an official No Parking Resolution for 161st Avenue, To continue posting 161st Avenue as No Parking after reconstruction, a Council resolution approving posting 161 st Avenue as No Parking will be required prior to MSA project approval. The street will also be required to meet an MSA 10-ton design standard. As with all MSA street segments, Staff collects traffic counts on 161 st Avenue on a 2 to 4-year cycle. Based off the most recent count taken in 2021, 161st Avenue has an Average Daily Vehicle (ADT) count of 1,000. The Traffic Impact Study performed for the PACT Charter School estimated a future 2,500 ADT at full build out. Based off these, Staff is estimating the required pavement section will be approximately 9 inches thick; 5 inches new bituminous pavement and 4 inches aggregate base. These numbers will be confirmed during project design, as Staff reviews the geotechnical report and GPR summary, as well as determines the most cost-effective pavement section / design method. Due to replacing the bituminous curb with concrete curb and gutter, and the need to meet MSA design standards, Staff anticipates minor impacts to existing driveways and boulevards along 161 st Avenue within the existing right of way. The project is proposing to add a 10-foot wide bituminous trail along the north side of 161st Avenue. This trail will connect to the existing pedestrian landing built with the 2020 Variolite Street reconstruction, and connect to the existing trail at the west side of Central Park. The existing trail from the Central Park drive to Armstrong Boulevard is proposed to be reconstructed with this project as well. All trail improvements will be required to meet MSA Standards, as well as ADA Standards. Municipal water and sanitary sewer utilities exist at the intersection of 161st Avenue and Variolite Street. These utilities will need to be extended to the west to connect the proposed PACT Charter School to municipal utilities. Staff is proposing to extend 8-inch sanitary sewer and watermain with this project, and is coordinating with PACT Charter for the location of their service connections. Utility lines to serve PACT Charter will be constructed to the right of way, which is expanding an additional 14 feet north as part of the PACT Addition. Staff is also proposing to stub sanitary sewer and water to the Saint Katherine Drexel site, and will coordinate the location and size of these lines with Saint Katherine Drexel. The residential properties south of 161st Avenue are not within the MUSA so Staff is not proposing to extend water and sewer services to any of these properties with this project. Stormwater runoff is currently handled through curb cuts and swales to existing ponding areas located in drainage and utility easements on the south side of 161st Avenue. Easements exist at 16045 Xenolith Street, which handles runoff on the eastern portion of the project, and a large ponding area on 7826 161st Avenue and 7833 159th Lane, which handles runoff on the western portion of the project as well as runoff from the Central Park parking lot. This project is proposing to replace the existing curb cuts and swales with storm sewer inlets placed in the curb lines and piping to the ponding areas. This is to remove the safety hazard of having storm water runoff flowing across the surface of 161 st Avenue as it currently does. Initial review of the topo indicates the ponding area on 7826 161st Avenue and 7833 159th Lane will need to be excavated deeper to accommodate piping. The storm sewer is proposed to handle the 161st Avenue corridor and existing drainage areas, no accommodations for PACT Charter or a future Saint Katherine Drexel development are being proposed. This will be further explored during project design. Estimated project costs per the 2022 — 2031 CIP are $548,939. These costs do not reflect the increase in costs Staff has observed during 2022 due to inflation in the construction industry. Additionally, the bituminous trail, watermain extension, and sanitary sewer extension was not included in the CIP estimated project costs. Staff has done a