TO: Members of the Governing Board
FROM: Christopher Silke, District Engineer
REPORT BY: Anna Martinez, Assistant Engineer
SUBJECT: Approval of Amendment No. 4 to Agreement No. 240306B (LBRID) with GHD, Inc.
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RECOMMENDATION
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Approve and authorize Amendment No. 4 to Agreement No. 240306B (LBRID) with GHD, Inc. to increase the contract amount by $16,000 increasing total compensation from $441,649 to $457,649 to provide additional construction management and inspection services for the “Wastewater Ponds Groundwater Inflow Mitigation Project, LB 18-02.” (Fiscal Impact: $16,000 Expense, Lake Berryessa Resort Improvement District; Budgeted; Discretionary)
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BACKGROUND
Heavy precipitation in the winter of 2017 filled the District’s wastewater ponds requiring overland disposal of wastewater from the District’s treated wastewater Pond 7 to prevent damage to the earthen pond berm should the pond exceed capacity and overflow. The overland discharge was in violation of the District’s Waste Discharge Requirements issued by the Central Valley Regional Water Quality Control Board (Regional Board). The Regional Board issued a Notice of Violation (NOV) in response to the discharge requiring the District to complete a water balance evaluation and submit a Work Plan if it was found that there is insufficient storage and/or disposal capacity.
The District Board authorized Agreement No. 170871B with GHD, Inc. in May 2017 to provide engineering study services necessary to address the requirement of the NOV. GHD 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. They recommended additional drainage improvements alongside Ponds 1 through 3 to reduce surface water runoff during intense storm events. GHD, on behalf of the District, submitted a workplan to the Regional Board conceptualizing design options to reduce groundwat...
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