TO: Members of the Governing Board
FROM: Chris Silke, District Engineer
REPORT BY: Anna Martinez, Assistant Engineer
SUBJECT: Approval of Plans and Specifications and Authorization to Advertise for Bids for Phase II of the “LBRID Wastewater Ponds Groundwater Inflow Mitigation Project” (LB 18-01)
RECOMMENDATION
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Approve the Plans and Specifications for Phase II of the “LBRID Wastewater Ponds Groundwater Inflow Mitigation Project” and authorize the advertisement for sealed bids, and opening of the bids at a time, date, and location to be published by the District Engineer pursuant to Section 20150.8 of the Public Contract Code. (No Fiscal Impact)
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BACKGROUND
Persistent heavy rainfall, runoff, and saturated soil conditions in the winter of 2017 filled Lake Berryessa Resort Improvement District (LBRID) wastewater ponds. Stored treated wastewater in Pond 7 had to be removed through the irrigation pump station and onto the land disposal fields to avoid damage to the earthen berm. Uncontrolled overland runoff ensued. The District’s Waste Discharge Requirements (WDRs) permit prohibits land application runoff beyond tailwater capture ditches that return flow back to the ponds. Central Valley Regional Water Quality Control Board (Regional Board) subsequently served the District with a Notice of Violation in April 2017. To address the violation, Regional Board ordered the District to complete a Revised Water Balance Evaluation and submit a Work Plan if it is found that there is insufficient storage and/or disposal capacity. The District authorized Agreement No. 170871B with GHD, Inc. in May 2017 to provide engineering study services. The scope of the investigation centered on Water Balance Update and Calibration Model tasks executed in conformance with the Regional Board guidelines. The review of the wastewater ponds and irrigation facilities was to assess the adequacy for storing and handling a 100-year annual return precipitation winter period. GHD, Inc. was also tasked with inspecting the original inlet piping constructed in the mid-1960s for Ponds 1 through 3. In their June 2017 Revised Water Balance Report, the engineering consultant team concluded the lack of any pond liner barrier or means to intercept groundwater flow upgradient of the ponds was responsible for large seepage inflow volume as soils became saturated in the winter of 2017. Additional drainage improvements alongside Ponds 1 through 3 would reduce surface water runoff during intense storm events.
GHD, Inc. published an Inflow / Infiltration Mitigation and Storage Expansion Work Plan as mandated by Regional Board. First initiatives recommended in the plan were to survey as-built bathymetry of storage ponds to estimate capacities, perform geotechnical exploration borings to bedrock or boulder refusal, sample soils for classification, and obtain contiguous northern perimeter surface topography adjacent to all ponds.
Amendment No. 1 to Agreement No. 170871B with GHD, Inc. was approved in March 2018 to advance the project into a technical feasibility analysis, furnish a geotechnical opinion on the suitability for constructing a groundwater cutoff wall, and mapping for future base plan design. GHD, Inc. stated in their geotechnical findings sub-report that the wastewater ponds site soils were conducive to an engineered vertical trench and drain pipe collector at the underlying bedrock interface surrounding the northerly perimeter of Ponds 1, 2, 3, 7 & 8. District staff compiled all technical project documentation and maps into a Final Feasibility Report filed with Regional Board in May 2018. Preliminary total project costs (engineering, permitting, administration and construction) to install a vertical trench drain, replace the vintage 10" tar-coated steel pond inlet pipe, re-grade drainage channels at the site and build earthen berm heights at Ponds 1 - 3 were estimated to be $1,250,000. A Clean Water State Revolving Fund (CWSRF) project application in the amount of $2,000,000 was filed with the State Water Resources Control Board, Division of Financial Assistance (DFA) in September 2018 seeking principal forgiveness to cover preliminary engineering, engineering design, permitting, administrative, and construction costs. Included with the application was LBRID Resolution 2018-05 authorizing the District Engineer to submit a principal forgiveness financial assistance application to the State Water Resources Control Board Division of Financial Assistance (DFA) and take related action to receive funding for the Project. State officials with Small Community Wastewater Grant Program oversight stated that the District would be potentially eligible for principal forgiveness if it maintains designation as a Disadvantaged Community (DAC). Rural Community Assistance Corporation (RCAC) was hired by the District to update its Median Household Income (MHI) because the DAC status had expired on December 31, 2017. RCAC household income survey methodology conforms with SWRCB standards. Certified results of the District's survey found the MHI to be $43,200 which is significantly below 80% of the statewide income average for DAC classification. Amendment No. 2 to Agreement No. 170871B with GHD, Inc. was approved in September, 2018, and expanded the scope of services to include additional design and bid-phase consulting services increasing the contract amount by $106,247 for a new maximum of $184,858.
Amendment No. 3 to Agreement No. 170871B with GHD, Inc. was approved in March 2019 to expand the scope of services for Stormwater Inflow / Infiltration Monitoring as ordered by the Central Valley Regional Water Quality Board. Engineering fees for the contract supplement added $46,488 to the budget for an adjusted total of $231,346.
Amendment No. 4 to Agreement No. 170871B with GHD, Inc. was approved in January 2020 expanding the scope of services to include a Preliminary Engineering Report in accordance with DFA Guidelines thereby increasing the consulting fees by $8,196 to a new maximum amount of $239,542.
Preliminary design plans and technical specifications for the project, including the addition of widening and raising the earthen berm height of Ponds 1 -3, were submitted to SWRCB and Central Valley RWQCB for review and comment in the fall of 2023.
On March 26, 2024, DFA signaled that issuance of a funding agreement was imminent, and staff recommended that the Board approve a new Agreement with GHD, Inc. to begin additional geotechnical design tasks related to upgrading the original treatment pond berms that would lead to preparation of final plans and specifications upon receipt and acceptance of the State Water Resources Control Board Funding Agreement. Available operations budget fund balance funded the new agreement and it is expected the soft costs are eligible for reimbursement under the CWSRF program guidelines.
In May 2024, the District Engineer received and signed a Groundwater Inflow Mitigation funding agreement as authorized by Resolution 2018-05, and on July 2, 2024, a fully executed funding agreement was issued by DFA in the amount of $2,265,934.
On July 23, 2024, Amendment No 1 to Agreement No 24036B with GHD, Inc. was approved by the Board. The Agreement added scope and increased compensation to the Agreement that would allow GHD, Inc. to complete the Plans and Specifications for the project as a whole - splitting the project scope into two phases thereby front loading construction of Phase I - the vertical trench drain - before winter 2025 followed by bid and construction of Phase II - the earthen berm plus inlet pipe work - over the 2025 construction season when site conditions are dry.
Phase I of the project - installation of the vertical trench drain - was advertised for sealed bids on August 20, 2024 and was awarded to the lowest responsive bidder, Benchmark Civil Construction of Napa, CA, on November 12, 2024. Construction of Phase I finished in May 2025, on time, under budget with the trench drain functioning per its designed intent.
The Plans and Specifications for Phase II are now complete and ready for approval by the Governing Board. The District Engineer is requesting authorization to advertise for construction bids. The Engineer’s Estimate for Phase II of the project is $1,200,000.
Requested Action:
1. Approve Plans and Specifications for Phase II of the “LBRID Wastewater Ponds Groundwater Inflow Mitigation Project” (LB 18-01) and authorization to advertise for sealed bids.
FISCAL IMPACT
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Is there a Fiscal Impact? |
No |
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Is it Mandatory or Discretionary? |
Discretionary |
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Discretionary Justification: |
LBRID received and accepted a CWSRF funding agreement as authorized by Resolution 2018-05. The design and construction appropriations allow staff to implement wastewater pond upgrades and comply with ordered directives by RWQCB. |
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Is the general fund affected? |
No |
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Future fiscal impact: |
The project will span multiple fiscal years; however, the grant award is expected to cover future project costs and reimburse LBRID for expenses incurred in prior fiscal years for design services. |
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Consequences if not approved: |
The Project will be stalled exposing the District to potential enforcement action by RWQCB. |
ENVIRONMENTAL IMPACT
ENVIRONMENTAL DETERMINATION: The proposed action is statutorily exempt from CEQA pursuant to CEQA Guidelines section 15262 as a feasibility or planning study for possible future construction or repairs, and categorically exempt from CEQA pursuant to CEQA Guidelines section 15301 as the repair, maintenance, or minor alteration of existing public facilities involving negligible or no expansion of existing or former use.