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The Terraphase Team key technical leads identified above under Task 1.1 (see Organizational Chart for roles), and our Geotechnical Engineer will identify site physical, chemical, permitting and operational constraints that will influence the proposed treatment wetland design and will consider alternative layout and excavation/grading options. We will identify site-specific opportunities to maximize treatment effectiveness for the proposed treatment wetland system and potential habitat creation options. Based on the site data collected by Fugro to date, we understand the existing site soils are partly impacted with lead, chromium, and total petroleum hydrocarbons (TPH). Additional soil characterization sampling requirements will be assessed; limited additional targeted soil sampling may be necessary to optimize the final Project design. Recommendations pertaining to the potential need for additional location -specific sampling will be provided to the City. Site utility constraints will also be evaluated through review of design or as -built drawings for existing facilities, and using targeted utility locating services. Additional soil or groundwater sampling would be outside the scope of this contract but can be conducted if necessary and authorized by a change order. The basin will likely need to be lined with either an impermeable or low -permeability liner to restrict or limit the potential for mobilizing and transporting existing soil contaminants in the basin sediments. This assumes that existing sediments/sub-surface soil will be stabilized to provide a suitable base for the proposed liner installation. The proposed lining of the pond is consistent with the design of other shallow Free Water Surface (FWS) open -water treatment wetlands, including the Discovery Bay pilot project and Prado Wetlands demonstration project. Excavation and disturbance of existing sediments should be minimized, and we understand that the City's initial design objective is to minimize the need for sediment disposal or import of substantial fill material. DELIVERABLES: Technical memo outlining results of the site opportunities and constraints assessment, with recommendations pertaining to the potential need for additional location -specific sampling TASK 2.4 — OPTIMIZATION OF CONCEPTUAL DESIGN AND WETLAND TREATMENT FEASIBILITY AND CONSTRUCTABILITY ASSESSMENTS (TASK DURATION: 8 WEEKS) The Terraphase Team key technical leads will build on the initial conceptual design and identify potential alternative Project layouts and potential treatment benefits associated with alternative design options intended to maximize denitrification, and removal of pharmaceutical/synthetic trace organic compound contaminants, and also with respect to the Project's wildlife habitat and vegetation restoration objectives. A minimum of three conceptual design alternatives will be presented that will vary in cost, permitting complexity, treatment wetland process design, and required long-term maintenance. Each design alternative will be intended to provide a balance of water quality and habitat enhancement. We intend to maximize the system performance through an iterative design process given the relatively small Project footprint. We understand the WPCP's current average dry -weather discharge is approximately 4.8 million gallons per day, with a daily total nitrogen loading rate about of 2,100 pounds per day. Consulting Services Agreement between City of San Leandro and Last revised September 10, 2019 Terraphase Engineering for Treatment Wetland Design Services Exhibit A — Page 22 of 38