Addendum No. 1 to the Buttonwillow County Water District IS/MND for the Wastewater Treatment Improvement Project

Addendum No. 1 to the Buttonwillow County Water District IS/MND for the Wastewater Treatment Improvement Project

The Buttonwillow County Water District (District), in cooperation with the State Water Resources Control Board (State Board), has concluded that an Addendum to the Initial Study/Mitigated Negative Declaration (IS/MND) for the District's Wastewater Treatment PlantImprovement Project (proposed project, SCH NO. 2022120090) should be prepared by the District. The Wastewater Treatment Plant Improvement Project was considered in the 2022 IS/MND and was approved by the District Board on February 2023 and the Notice of Determination was filed on February 23, 2023. As the project proceeded to final engineering, the project engineers determined that the site plan approved by the Board would need revisions in order to better serve the needs of the District but still function properly and comply with discharge requirements of the Central Valley Regional Water Resources Control Board (Regional Board). Although all of the original wastewater treatment facilities will remain the same, the location of these facilities has been modified and rearranged on the District’s property. Hence, this Addendum is being prepared to address whether the modifications to the site plan for the Buttonwillow Wastewater Treatment Plant (WWTP) Improvement Project may cause greater adverse impacts to the environment than the approved WWTP facilities. Project Characteristics As indicated in the Project Description, the specific project being evaluated in this document consists of a Wastewater Treatment Plant Improvement Project. This evaluation relies on data in the IS/MND (2022) and new data collected specifically for the new WWTP facilities. The following three proposed WWTP facilities will be constructed/demolished at the same location in both site plans: • A 16-foot wide, aggregate base road will be constructed on District property to provide access to the WWTP site. This road will extend from the paved terminus of Sullivan Road to the east and then south along the Meadow Street alignment to the edge of the District property. • A six-inch potable water line will be extended from south of the Main Drain canal (starting at the intersection of Sudan Avenue and Meadow Street) north to the WWTP project site (approximately 3,400 feet) to the Biolac treatment facility located just south of the Sullivan Road alignment. • The existing WWTP will be demolished, except for the existing Lift Station, which will be rehabilitated in place to deliver influent wastewater to the new WWTP. The following new facilities or relocated facilities will be implemented once the project has been approved and funded. The proposed two-acre Solar Field Site has been relocated from the agricultural field on the west side of the extension of Meadow Street to the northeast corner of the District’s WWTP property, just south of the Sullivan Road alignment. The Solar Field is proposed to generate 320 kilowatts (kW), which equates to approximately 500,000 kWh/year. The facility is anticipated to offset the full energy demand of the new WWTP on an annual basis. Two new sludge drying beds (50’ x 120 feet) will be installed just west of the Solar Field, and immediately east of the Meadow Street extension. Approximately 1,000 cubic yards (CY) will be excavated from the drying beds and the beds will be lined with concrete. The goal is to use the excavated material onsite as part of balancing earthwork, such as elevating the WWTP area by about 4. Standard construction equipment will be used to carry out the excavation and fill. A new pond will be installed south of the two existing effluent ponds. This triangular pond will have the following approximate dimensions: 190 feet (north boundary); 240 feet (east boundary); 54 feet (south boundary); and 276 feet (west boundary). This new pond will require excavation of approximately 4,000 CY total. Excavated material will be balanced onsite with pond berms and other WWTP earthwork. Standard construction equipment will be used to carry out the excavation and fill. A new emergency pond will be installed on the southern portion of the District’s WWTP property, adjacent to the Meadow Street road extension. This emergency pond will have the following approximate dimensions: 220 feet (north boundary); 400 feet (east boundary); 440 feet (south boundary); and 336 feet (west boundary). This new emergency pond will require excavation of approximately 14,000 CY total. Excavated material will be balanced onsite with pond berms and other WWTP earthwork. Standard construction equipment will be used to carry out the excavation and fill. Project Description (continued): • Two new 30-foot diameter clarifiers will be installed within the new WWTP project area. These two clarifiers will be constructed of reinforced concrete. • A new office will be installed between the WWTP site and the sludge drying beds. The office will have a concrete foundation and will be constructed as a metal or concrete block wall building. A blower shed will also be installed on the north side of the WWTP site. It will have a concrete foundation and will be approximately 25’ x 20’ in size. An electrical service connection to the WWTP will be constructed just southwest of the Blower Shed. • A chain link fence will be installed to protect the proposed facilities. Total fence will be approximately 7,000 feet in length and 8 feet high. • Effluent pipelines will deliver the treated effluent to the two effluent ponds. The total length of these pipelines is approximately 1,300 feet and they will range in size with the largest pipeline being 12-inch diameter. Maximum depth of all pipelines to be installed is estimated to be 10 feet. • A Sludge Digestion/Dewatering pipeline will connect the solids portion of the effluent to the two sludge drying beds. This pipeline will be approximately 200 feet long and 12 inches in diameter. • The Biolac Pond will be approximately 75’ x 125’ in size and it will require excavation of approximately 2,900 CY of material. This Pond will also be lined with concrete. The engineering design estimates that the material not used for the Pond’s berm will be about 535 CY and this material will be used onsite to balance earthwork. • The wastewater delivered to the WWTP will enter the system at a fine screen that will be constructed upstream of the Biolac Pond. This screen will remove the trash and solid waste that gets transported along with the wastewater. The engineers estimate that construction of the above facilities will occur over a 16 to 20-month period. However, most of the ground disturbing activities (heavy equipment for earthwork and structure construction) will occur over an 8 to 12-month period. In summary, the project footprint (termed the Area of Potential Effect (APE) for cultural resources) will be altered substantially for the current project (2024) when compared to the approved 2022 WWTP project. No facilities are proposed west of the extension of Meadow Street any longer, but based on the new site plan (design), the whole of the District’s property east of the Meadow Street extension will now be utilized to replace the existing WWTP, rather than just the southern and central portions of the property.

Buttonwillow

Kern

Unincorporated

California Air Resources Board (ARB), California Department of Conservation (DOC), California Department of Fish and Wildlife, Central Region 4 (CDFW), California Department of Parks and Recreation, California Department of Pesticide Regulation (DPR), California Department of Resources Recycling and Recovery, California Department of Toxic Substances Control (DTSC), California Department of Transportation, District 6 (DOT), California Department of Water Resources (DWR), California Fish and Game Commission (CDFGC), California Governor's Office of Emergency Services (OES), California Highway Patrol (CHP), California Native American Heritage Commission (NAHC), California Natural Resources Agency, California Public Utilities Commission (CPUC), California Regional Water Quality Control Board, Central Valley Fresno Region 5 (RWQCB), Central Valley Flood Protection Board, Office of Historic Preservation, State Water Resources Control Board, Division of Drinking Water, State Water Resources Control Board, Division of Drinking Water, District 19, State Water Resources Control Board, Division of Water Rights, State Water Resources Control Board, Divison of Financial Assistance

Other (WWTP >50,000 gpd; Sewage Pipeline)

Replace WWTP

Aesthetics, Agriculture and Forestry Resources, Air Quality, Biological Resources, Cultural Resources, Drainage/Absorption, Energy, Flood Plain/Flooding, Geology/Soils, Greenhouse Gas Emissions, Hazards & Hazardous Materials, Hydrology/Water Quality, Land Use/Planning, Mandatory Findings of Significance, Mineral Resources, Noise, Public Services, Recreation, Sewer Capacity, Solid Waste, Transportation, Tribal Cultural Resources, Utilities/Service Systems, Vegetation, Wetland/Riparian