West Hills Water Treatment Plant

West Hills Water Treatment Plant

Description of Current Project: As evaluated in the 2014 WHWTP EIR, the District is implementing an expansion of the WHWTP design capacity from 4.5 MGD to 6.75 MGD. The expansion is necessitated by forecasted increases in treated water demand and the need for drought resilience in the District’s service territory. The expansion will be based on retaining the same processes and system design as the existing WTP. The main components of the expansion include: • One new 2.25 MGD raw water pump added to the existing raw water pump station (RWPS) • One new 4.5 MGD automatic strainer added upstream of Actiflo-Carb • One new 4.5 MGD ballasted clarification pretreatment based on Veolia’s Actiflo Carb treatment process • One new 2.25 MGD dual media gravity filter with plastic block underdrains • Chemical feed and storage facilities: o One 2500-gallon sulfuric acid storage tank o One 6650-gallon sodium hydroxide storage tank • One new 500,000-gallon prestressed concrete clearwell tank • One new solids drying bed sized for the 2.25 MGD expansion. The environmental analysis contained in the 2014 WHWTP EIR considered future expansion and installation of additional water treatment equipment and related improvements to a buildout capacity of 9 MGD. Thus, the current interim expansion falls within the design capacity evaluated in the EIR. Determination: Pursuant to Public Resources Code Section 21166 and CEQA guidelines 15162, the District has determined that (1) there is substantial evidence that none of the conditions requiring preparation of a subsequent or supplemental EIR exist, and (2) the District will rely on the previous environmental document, which adequately addresses this project. The District further determines that: (1) No Substantial changes are proposed in the WHWTP project which will require major revisions of the previous EIR due to the involvement of new significant environmental effects or a substantial increase in the severity of previously identified significant effects; and, (2) No Substantial changes occur with respect to the circumstances under which the project is undertaken which will require major revisions of the previous EIR due to the involvement of new significant environmental effects or a substantial increase in the severity of previously identified significant effects; (3) No new information of substantial importance, which was not known and could not have been known with the exercise of reasonable diligence at the time the previous EIR was certified, demonstrates that any of the following is true (that is, the response to criteria a through d below is “false”): a. The project will have one or more significant effects not discussed in the previous EIR; b. Significant effects previously examined will be substantially more severe than disclosed in the previous EIR; c. Mitigation measures or alternatives previously found not to be feasible would in fact be feasible, and would substantially reduce one or more significant effects of the project, but the District declines to adopt the mitigation measure or alternative; or, d. Mitigation measures or alternatives which are considerably different from those analyzed in the previous EIR would substantially reduce one or more significant effects on the environment, but the project proponents decline to adopt the mitigation measure or alternative. Section 15162 of the State CEQA Guidelines states that when an EIR has been certified or a negative declaration adopted for a project, no subsequent EIR or Negative Declaration shall be prepared for that project when the lead agency can make certain findings based on substantial evidence. Therefore, based on the criteria contained in Section 15162 of the State CEQA Guidelines it is found: 1. That there have been no substantial changes proposed in the project which would require major revisions to the previous EIR due to the involvement of new significant environmental effects or a substantial increase in the severity of previously identified significant effects. The proposed project treatment plant design capacity expansion will be contained within the area previously assessed in the 2014 EIR. The design capacity expansion from 4.5MGD to 6.75 MGD lies within the bounds of the 9 MGD buildout design capacity evaluated in the previous EIR. 2. All new equipment and modifications will remain on the previously approved WHWTP area, so there are no new significant environmental effects or a substantial increase in the severity of previously identified significant effects resulting from the new equipment and capacity expansion. Therefore, the proposed project would not require any revisions to the previous EIR. 3. That no substantial changes have occurred with respect to the circumstances under which the project is undertaken which will require major revisions in the previous EIR due to the involvement of new significant environmental effects or a substantial increase in the severity of previously identified significant effects. The existing land uses in the surrounding vicinity and within the project area have not undergone any substantial changes since they were described and analyzed in the original project EIR, so there is no substantial increase in the severity of any previously identified environmental effects that would require revisions in the EIR. The General Plan land use designations for the area have not been changed, and the EIR anticipates eventual buildout to 9MGD capacity. Therefore, the circumstances under which the project is undertaken have not changed substantially, and no revisions to the previously adopted EIR are required. 4. That no new information of substantial importance, which was not known and could not have been known with the exercise of reasonable diligence at the time the EIR was certified, has become available. The WHWTP design capacity expansion does not include any new information of substantial importance regarding significant effects from project implementation that were not previously discussed, identified, and analyzed in the certified EIR. 5. There has been no new information submitted that demonstrates that significant effects would occur that were not discussed in the EIR and there has been no new information submitted to demonstrate that previously identified significant effects will be substantially more severe. The existing mitigation measures were found to be effective and feasible at the time of certification of the EIR, and there have been no substantial changes to the project or the project circumstances that would change the mitigation measures. Therefore, no new information that contradicts the analysis in the EIR has become available since the EIR was certified by the District. Therefore, in accordance with Section 15162 of the CEQA Guidelines, the Final EIR (SCH #2012081028) still applies to the project, and there is no substantial evidence that the project as modified could have a potentially significant effect on the environment beyond what was previously analyzed.

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San Benito

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San Benito