Planning/Design/Engineering/Environmental Documentation. Task 3: Assessment and Evaluation Preliminary engineering studies and evaluations of the project were completed in October 2009. USGS completed two studies for the project (listed below) and constructed a monitoring well. The multi-level monitoring well is at the recharge pond site and is used to monitor and verify percolation of recharge water and recovery of the groundwater levels. Ongoing monitoring of groundwater basin nitrate levels will be conducted. Two USGS and one Xxxxx Engineering reports have been drafted for this study:
Planning/Design/Engineering/Environmental Documentation. Task 2: Assessment and Evaluation Several studies have been completed or will be completed for this project. • A Collection system Master Plan was completed in 2008 and developed the strategy for sewer system implementation. The collection system master plan included development of a hydraulic model of the District’s proposed sewer system to determine the infrastructure needed to meet the District’s near-term and build-out service conditions. The master plan established project phasing, conceptual level design criteria, preliminary pipeline and pump station configurations, and conceptual level construction cost estimates. • A Preliminary Design Report (PDR) for the Water Reclamation Facility was completed in January 2009. The PDR includes a description of the project background, descriptions of the anticipated performance requirements, a review of available technologies, review of biological treatment technologies, descriptions of the unit processes and site development, preliminary layout plans, anticipated cost, anticipated construction schedule, and project implementation constraints. • A Value Engineering Study for the Collection System Master Plan and Wastewater Reclamation Facility PDR was conducted in 2008. . The purpose of the VE is to find design improvements to provide a more cost effective system.
Planning/Design/Engineering/Environmental Documentation. Planning, design, engineering, and environmental documentation are not required in this project.
Planning/Design/Engineering/Environmental Documentation. The design of project facilities is planned to be completed in concurrent efforts for each of the major engineering components: collection system, treatment system, and disposal/reuse system. Although design will occur concurrently, the design packages will be completed at different times, allowing construction to begin in phases as designs are completed. Each of these designs will be according to civil and mechanical engineering industry best practices with national standards used for materials, piping, equipment, and general construction specifications. Construction documents and contracts will include Section 7 Caltrans State Standard Specifications and the requirements of the State labor code for Public Works projects in accordance with the Labor Compliance Plan.
Planning/Design/Engineering/Environmental Documentation. Task 3.1: Assessment and Evaluation Further assessment and evaluation work is needed in hydrology and hydraulics to verify that the spillway can pass the Probable Maximum Flood (PMF) with adequate residual freeboard as required by DSOD (i.e., the dam crest must be 1.5 ft above the lake water surface at PMF peak). PMF is based on the Probable Maximum Precipitation (PMP) event. Further assessment and evaluation work in geotechnical engineering will have three main elements: (1) consultation with DWR/DSOD to determine the project-specific field exploratory drilling, testing and geotechnical engineering analyses that will be required; (2) perform the required field exploratory drilling and testing; and (3) perform the required geotechnical engineering analyses. 2 Since the MOA primarily addresses joint use of Phoenix Lake for flood control and water supply, it has been included under both the Flood Damage Reduction Project and the Water Supply Project. The cost to prepare the MOA has been split 50/50 between these two projects, as reflected in the Budget. 3 The cost for reporting has been split across all five component projects comprising the Retrofit according to each project’s pro-rata construction cost, as reflected in the Budget. For purposes of this grant agreement, it is anticipated that the required field exploratory drilling and testing work will include six (6) borings in the dam and two (2) borings in the two landslides and laboratory testing of the boring materials, including moisture density, strength (TXCU/pp), PI, and grain size. It is anticipated that the required geotechnical engineering analyses will include more refined (i.e., more refined than the previously completed analyses) stability and deformation analyses based on the new field data. All work, including field data, testing, and analyses, findings, and conclusions verifying feasibility and viability of the geotechnical aspect of the Project will be documented in a Geotechnical Pre-Design Report. A Coordinated Operations Plan (COP), establishing the rules and criteria for operating the lake in a manner that achieves the lake’s new multi-use benefits will be developed that is mutually acceptable to MMWD and FZ9. Details on the COP are provided in the Water Supply Project tasks discussed below.4
Planning/Design/Engineering/Environmental Documentation. Task 3.1: Assessment and Evaluation In order to more thoroughly assess and evaluate the long term yield of the Water Supply Project, further long- term hydrologic analysis covering shortage years is needed. The Phoenix Lake operations model previously developed will be used again for this further analysis. A Coordinated Operations Plan (COP) will be developed that is mutually acceptable to MMWD and FZ9, establishing the rules and criteria for operating the lake in a manner that achieves the lake’s new multi-use benefits. The operating rules and criteria will govern lake levels, withdrawals for water supply, and operation of the spillway gate. The COP will also describe instream flow releases for ecosystem restoration in Xxxx Creek below the dam and lake levels for public recreational uses of the lake. The Phoenix Lake operations model and findings of the instream flow study of Xxxx Creek and lower Corte Madera Creek (see section the Ecosystem Restoration Project Task 3.4: Permitting) will be used in developing the COP. It is anticipated that the COP will be incorporated into the MOA.9 It is anticipated that the above-described work will be performed by an engineering consultant-contractor with review and oversight by FZ9 staff. MMWD staff will also provide review-and-comment services.
Planning/Design/Engineering/Environmental Documentation. Task 3.1: Assessment and Evaluation The Concept (30%) Design Memorandum has adequately verified the engineering feasibility and viability of the two circulation devices; therefore, no further engineering assessment and evaluation work is needed. However, further assessment and evaluation of baseline (existing, or pre-construction) water quality conditions in the lake is needed. Further assessment and evaluation of existing water quality conditions will include pre-construction water quality monitoring summarized in the table below. 11 The cost for reporting has been split across all five component projects comprising the Retrofit according to each project’s pro-rata construction cost, as reflected in the Budget. Monitoring Plan for Baseline (Existing) Conditions Description What • Water quality (Secchi depth and vertical profiles of Chlorophyll-a, dissolved oxygen, and iron and manganese) • Water temperature (vertical profiles of water temperature) Why • Provide data to establish baseline conditions for evaluating project performance When • Monthly sampling of water quality in the months from April through October: o Pre-construction • Continuous monitoring of water temperature in the months from April through October: o Pre-construction Where • Near the dam and near the proposed circulation devices Who • FZ9 contractor Deliverables: Report on Baseline Water Quality Conditions in Phoenix Lake
Planning/Design/Engineering/Environmental Documentation. Task 3.1: Assessment and Evaluation The Concept (30%) Design Memorandum has adequately verified the engineering feasibility and viability of the low-flow control gates; therefore, no further engineering assessment and evaluation work is needed. However, further assessment and evaluation is needed of baseline (existing, or pre-construction) water quality conditions below Phoenix Lake in Xxxx Creek and Corte Madera Creek. This will aid in identifying the important sources of concentrations of low dissolved oxygen and high iron and manganese. Deliverables: Report on Baseline Water Quality Conditions below Phoenix Lake in Xxxx Creek and Corte Madera Creek
Planning/Design/Engineering/Environmental Documentation. Task 3.1: Assessment and Evaluation The completed work has adequately assessed and evaluated the Recreation and Public Access Project and verified its feasibility and viability; therefore, no further assessment and evaluation work is needed.
