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Staff recommends that City Council approve the agreement to Mark Thomas for the not- to-exceed amount of$524,145 to complete the 35 percent design of the proposed West Las Positas Boulevard Multimodal Reconstruction Project, CIP No. 11514. RECOMMENDATION 1. Approve a professional services agreement with Mark Thomas of San Jose, California, in the not-to-exceed amount of$524,145 for the 35 percent design services for the West Las Positas Boulevard Multimodal Reconstruction Project, CIP No.11514. 2. Authorize the City Manager to execute the agreement. FINANCIAL STATEMENT Project funding totals $7.24 million with $1.2 million expended/encumbered on previous maintenance, investigations, and designs, leaving a balance of$6 million for design and construction of the project. Approximately $2.7 million dollars of the $6 million in available funding is comprised of bike and pedestrian funding that is not eligible to be utilized on utility and road subgrade reconstruction. The total anticipated 35 percent design-related expenditure is $524,145. BACKGROUND West Las Positas Boulevard is a key east-west arterial roadway and a critical connection for the city's bicycle, pedestrian and transit networks, providing a primary link from residential to regional trails, schools, retail and office land uses. The portion of the road between Hopyard Road and Stoneridge Drive was constructed in the early 1980s as part of the Hacienda business park. The West Las Positas roadway has a history of soil settlement and differential movement within Hacienda that has created an uneven roadway surface and some localized roadway failures. The City has implemented several maintenance repairs projects, pilot repair projects and geotechnical investigations over the years to remediate the uneven roadway that is experiencing pavement distress and/or settlement. The various repairs have provided a short-term fix, but these repairs have not lasted as long as anticipated. In October 2021, City Council awarded a contract to BSK Associates (BSK) to conduct an extensive geotechnical study to identify the causes of the roadway failures and come up with recommended repair strategies. The study included the collection of soil samples from 19 locations (borings) with the collections occurring at varying depths from 7 to 40 feet deep as well as reviewing similar soil investigations from adjacent properties. The borings identified that the area consisted of expansive clay soils 35 to 40 feet deep that have consolidated and are highly susceptible to shrinkage and contraction when dried out. The study determined the primary cause of settlement is attributed to the loss in soil moisture along the roadway edges and medians within the top five feet of soil, causing the surficial soils —that are highly susceptible to shrinkage and swelling —to contract when dried out. Factors affecting the loss in soil moisture include vegetation, exposure to the environment, and climate. The roadway approaches to Chabot Canal and Tassajara Creek are additionally impacted by soil creep', which is occurring along the channels. ' the slow, downward progression of rock and soil down a low-grade slope Page 2 of 5