RFQ Design - Upper Highline Spillway Rehabilitation

Projected Scope of Work PROJECT OBJECTIVES The primary objectives of this Project are twofold. The first objective is to provide analysis and design services to produce all construction documents necessary to replace the existing concrete emergency spillway at Upper Highline Dam. The following summarize specific scope items anticipated to be included in the project. It should be noted that a Spillway Hydrologic Adequacy Report for Upper Highline Dam, which included and Inflow Design Flood Hydrology Analysis and Hydrologic Hazard Classification Analysis, was approved by the SEO in 2021. This report is included in the RFQ supplemental information Google Drive. The Consultant should thoroughly review this document and note any shortcomings or discrepancies that are of sufficient concern that the Consultant does not believe that they can use the report as a basis of design. a. Alternatives analysis: Includes review of all record documents, drawings, previous design reports, analysis, etc. to help achieve a holistic understanding of the structure and aid in development of alternatives. Develop up to three design alternatives and provide schematic level drawings, preliminary analysis, and preliminary cost estimates for each alternative. b. Perform all necessary hydraulic calculations, modeling, and sensitivity analyses on the selected alternative to ensure design compliance with the SEO Rules and Regulations. c. Develop and provide a complete design submittal package in accordance with Rule 6 of the SEO Rules and Regulations. d. Assist CPW with development of a construction bid package to be used in a formal Invitation for Bid (IFB) solicitation. This scope element should include assistance with select front end specifications such as bid schedule, summary of work and measurements and payments. This scope item may be adjusted if CPW elects to pursue a CMGC delivery method for this project The second, objective is to evaluate the current seepage condition and subsequently the potential for internal erosion (CLE) through the foundation leading to a dam failure. If results from this objective indicate that internal erosion is a dam safety concern that should be addressed, then seepage mitigation design may be included as an amendment to the design contract. The following summarizes the overall scope items related to the seepage and internal erosion analysis anticipated to be included in the project. a. Review all historic documentation, past reports, etcetera to help achieve a holistic understanding of the structure and aid the evaluation. b. Testing of water samples from foundation piezometers and the downstream toe area for sulfate levels. It should be noted that Upper Highline Reservoir's primary water source is Government Highline Canal which has significant agricultural loading. c. Analyze samples collected from item (b). Based upon the chemical makeup of the results, evaluate the potential for further gypsum dissolutioning that would lead to initiation of internal erosion. d. Based upon the test results and analysis in the items (b) and (c) above, analyze the potential for progression to occur through a seepage model given past improvements. e. Based upon the results for scope items (a)-(d) revisit 2023 CDSE results for PFM 9 and evaluate if the additional analysis has changed the likelihood of the PFM.

Division 02 -	Existing Conditions, Subsurface Investigation.
Division 31 -	Earthwork, Site Clearing, Grading, Excavation and Fill, Subgrade Preparation, Excavation, Shoring, Tunneling and Mining, Tunnel Excavation.
Division 35 -	Waterway and Marine Construction, Dam Construction and Equipment.