On-Call Engineering and Water Supply Planning Services

EKI has been working with Valley of the Moon Water District (VOMWD) since 2014 and has successfully completed water supply, conservation, and infrastructure design and construction support projects.

• Water System Master Plan: EKI prepared the District’s 2019 Water Master Plan, which serves as the basis for the District’s 25-year CIP. As part of this effort, EKI constructed and calibrated a new GIS-based hydraulic and performed a storage and supply evaluation. To construct the hydraulic model, EKI converted the District’s CAD maps into a geodatabase of all the water system facilities.
• On-Call Hydraulic Modeling: EKI has performed on-call hydraulic modeling evaluations to support operational decisions and evaluate alternative improvement projects, including evaluating the need for a temporary bypass during construction of the Boyes Avenue Bridge Project, alternative water main improvement in lieu of the Saddle Tank Replacement Project, implications of deferring replacement of the 8-inch main on the Arnold Drive Bridge until the bridge is repaired or replaced, and fire flow availability for a new development.
• Engineering Design:
  • Park Avenue Well Replacement, Chestnut Exploratory Borehole, and Aquifer Storage and Recovery: EKI prepared design documents for the construction and equipping of a replacement supply well at the District’s Park Avenue Well site. The well is located in fractured bedrock, and the design included a new submersible well pump, piping, appurtenances, and connections to the existing well system. The design also included the drilling of an exploratory borehole at a nearby tank site to assess whether a permanent supply well could be constructed at that location. The drilling portions of the project were repackaged as part of the District’s ASR project, which also includes three dual-nested monitoring wells at the Park Avenue and Well 5A sites. The drilling portion of the ASR project was recently completed and EKI is providing construction and testing oversight. EKI prepared a feasibility study to determine whether the Park Avenue Well and Well 5A are suitable for ASR operations, and implemented a pilot test at each well site in Fall 2024. Additionally, EKI assisted the District in obtaining approximately $3 million of drought-relief funding from the Department of Water Resources to support the ASR project.
  • Altimira Fire Flow Improvements Design:EKI is preparing plans, specifications, and cost estimates to replace approximately 5,000 LF of existing 6-inch and 8-inch water mains with new 12-inch PVC water mains to improve fire flows. The project includes relocating portions of the water main along with a pressure-reducing valve.
  • Well 5A Production Well Replacement: EKI prepared design documents, performed construction management, and led permitting for the Well 5A Production Well Project, which included construction of a new well cased to a depth of 692 feet, rehabilitation and refurbishing the existing iron and manganese treatment system, and piping and appurtenant work.
  • Well 5A Treatment and Water Quality Investigations: Water quality testing during construction of Well 5A, which replaced an existing well at the same site, showed that there were elevated levels of arsenic, iron, and manganese, as well as a periodic hydrogen sulfide odor in the groundwater. The well system already had a greensand filter to remove iron and manganese, so EKI developed a design for a new ferric chloride feed system that would allow the existing filters to co-precipitate and remove the arsenic and a residuals management system. To address the hydrogen sulfide odors, EKI developed a scope of work for a driller to perform zone testing and oversaw water quality testing of hydrogen sulfide during scope implementation. While the testing identified areas of higher hydrogen sulfide, additional testing may be done to further isolate and test specific water bearing zones to make a final recommendation on well modifications.
• Storage Tank Evaluations:
  • Richards Boulevard Tank: EKI prepared a siting evaluation for a potential new prestressed concrete water storage tank, including a conceptual site layout, hydraulic modeling evaluation to determine if the tank site will benefit operations and improve fire flow availability, cost estimate, and a constructability review.
  • Evaluation of Storage and Supply Requirements for Glen Ellen: EKI prepared several studies related to new storage tanks in Glen Ellen (Pressure Zone 1F). EKI performed an analysis to identify potential tank sites by reviewing properties located at elevations that match the Pressure Zone 1F hydraulic grade line. For one of these sites, EKI prepared site maps and cost estimates for a new partially buried prestressed concrete tank to support negotiations with property owners. EKI also recently updated the storage and supply evaluations for Pressure Zone 1F that EKI previously prepared as part of the 2019 Water Master Plan to account for storage within the Sonoma County Water Agency (SCWA) Aqueduct and recent improvements.
• Grant Funding: EKI prepared the District’s application for the Department of Water Resources Urban and Multibenefit Drought Relief Grant to implement several groundwater supply and ASR projects. The District was recently awarded over $3.4 million in grant funding to replace the Park Well and implement ASR at the Park Well and Well 5A sites.
• Permitting Support: EKI assisted VOMWD with updating its water system permit from the State Water Resources Control Board, Department of Drinking Water. VOMWD is adding two new wells to its system, as well as replacing onsite chlorine generators with liquid chlorine at seven additional wells. EKI developed and compiled the permit package including preparing drinking water sources assessments and documenting the final construction for the two new wells, compiling documentation that all materials and chemicals in contact with water are certified as compliant with National Sanitation Foundation, Standards 60 or 61, and developing system schematics and site plans.
• Third-Party Review: EKI provided a third-party engineer review of the County of Sonoma’s Boyes Boulevard Bridge Replacement Project related to the replacement of the water main attached to the existing bridge and recommended several design changes, including installation of EBAA Iron Flex-Tend Couplings.
• Engineering and Water Resources Support for System Consolidation: EKI is providing engineering and water resources support related to consolidation of the Sonoma Developmental Central (SDC) water system with the District’s water system, as part of redevelopment of the SDC site. EKI completed a water supply model to assess the reliability of the SDC’s existing surface water supplies and is preparing a Water Supply Assessment to support the SDC Specific Plan. EKI is currently preparing an engineering evaluation to assess the required infrastructure needed to consolidate and transfer flows between the two systems and is preparing a transition plan that maps out permitting requirements and next steps.
• Urban Water Management Planning: EKI prepared the District’s 2020 UWMP and Water Shortage Contingency Plan (WSCP) in accordance with the California Department of Water Resources UWMP Guidebook requirements.

Outcome

EKI continues to support the District in various capacities and projects. EKI is currently preparing a Water Supply Assessment, engineering evaluation to assess the required infrastructure needed to consolidate and transfer flows between the two systems, and a transition plan that maps out permitting requirements and next steps.