Time Set 9.
Planning Commission
- Meeting Date:
- 07/13/2023
Information
SUBJECT
ZF #2023-0012: Public hearing to consider approval of the CEMEX Dewatering Project at the Solano Concrete Off-Channel Mine facility and adoption of an Addendum Environmental Impact Report (EIR) to the previously certified EIR for the CEMEX Long-Term Mining Permit (SCH#96012034). The project location is 30288 State Route 16, approximately 3 miles east of Esparto (APNs: 025-450-001; 049-060-004, -007; 049-070-004, -005, -006, -009, -010, -011, -019, -020, -021). Owner/applicant: United Metro Materials Inc, and Solano Concrete Co Inc/CEMEX Construction Materials Pacific, LCC (Planner: C. Tschudin)
SUMMARY
| FILE # 2023-0012 | |
| APPLICANT: CEMEX Construction Materials Pacific, LLC |
OWNER: United Metro Materials, Inc and Solano Concrete Co Inc, together dba CEMEX |
| LOCATION: 30288 State Route 16, approximately 3 miles east of Esparto. (APNs: 025-450-001; 049-060-004, -007; 049-070-004, -005, -006, -009, -010, -011, -019, -020, -021) GENERAL PLAN: Agriculture (AG) ZONING: Agriculture Intensive (A-N)/Sand and Gravel Overlay (SG-O) SUPERVISORIAL DISTRICT: 3 (Supervisor Sandy) 5 (Supervisor Barajas) PUBLIC HEARING NOTICE: Published in Davis Enterprise 6/30/2023; notice to neighbors sent on 7/3/2023 |
SOILS: Sn, So, Ya, BrA, Lm, Sh, Ca FMMP: Multiple WILLIAMSON ACT: N/A FLOOD ZONE: AE, X FIRE SEVERITY ZONE: Moderate, Non-Wildland/Non-Urban |
| ENVIRONMENTAL DETERMINATION: Addendum EIR (SCH#96012034) | |
RECOMMENDED ACTION
- Hold public hearing to receive staff presentation and public comment;
- Adopt the Addendum EIR (Att. B) as the appropriate level of environmental documentation in accordance with the California Environmental Quality Act (CEQA) and CEQA Guidelines;
- Adopt the Findings to approve the requested dewatering activities (Att. C); and
- Approve the amendment to CEMEX Mining Permit (ZF95-093) to allow limited dewatering subject to certain specified conditions (Att. D).
REASONS FOR RECOMMENDED ACTIONS/BACKGROUND
CEMEX proposes to amend its existing mining permit (ZF95-093) to allow limited dewatering activities at the Solano Concrete Off-Channel Mining facility. "Dewatering" means lowering the water level in a wet pit by pumping water from the pit, regardless of the purpose of the pumping. Section 10-4.412 of County Code allows dewatering if site-specific analysis prepared by a qualified Professional Engineer or Professional Geologist demonstrates that the dewatering would not result in off-site impacts to groundwater or other water resources (creeks and wetlands).
CEMEX is currently mining Phase 4 of their approved mining plan using a combination of conventional excavator and an electric clamshell dredge and has already started to backfill the west side of Phase 4 for reclamation to agriculture (see Attachment A for Phase 4 mining location). Since 2021, CEMEX has worked to excavate clay below the groundwater table using the dredge so that the resources beneath the clay layers can be mined. However, the excavators cannot fully remove the clay layer to access the mineral resources below the clay and water. This results in CEMEX being unable to fully excavate the area to the permitted mining depth, leaving valuable aggregate resources in portions of the Phase 4 mining area. Yolo County's Cache Creek Area Plan, the governing plans and ordinances that regulate the County's mining program, encourages mining activities to excavate aggregate resources to the deepest extent possible to minimize the size of the mining footprint and have the least impact to agriculture. Utilizing excavators to wet mine also results in increased safety hazards such as submerged working platforms and unstable footing next to water. For example, in 2022, an excavator lost footing in the Phase 4 pit and the excavator sank to the bottom of the pond. This incident was investigated/monitored by several state and federal agencies and the excavator was removed under federal supervision to ensure there was no impact to groundwater resources.
The proposed dewatering consists of a pit-to-pit transfer of water from Phase 5 to Phase 4. The water then recharges back into the aquifer or could be used to irrigate on-site agriculture. The proposed dewatering from Phase 5 to Phase 4 would allow CEMEX to mine the areas using conventional equipment to remove the middle clay layers and mine to the full permitted depth of the sand and gravel deposits.
CEMEX requests that some of the water pumped from Phase 5 be used for onsite agricultural irrigation. Sagara Farms began the process of re-leveling the Phase 1 field for reclamation to agriculture in 2021 and planted crops in 2022. The water is proposed to be used to irrigate Sagara Farm crops in the newly reclaimed agricultural field.
Analysis
In 2017 the Board of Supervisors amended the Off-Channel Mining Ordinance to allow dewatering for mining activities with Planning Commission approval pursuant to sections 10-4.506 and 10-4.602 of Yolo County Code. Per the amended ordinance, no off-channel excavation shall use dewatering as a part of surface mining operations, unless site-specific technical analysis performed by a qualified Professional Engineer or Professional Geologist with experience in hydrogeology demonstrates that the proposed dewatering will not adversely affect off-site wells with respect to groundwater level and quality. Per the code, the Professional Engineer or Professional Geologist shall demonstrate, using appropriate hydrogeologic analysis (i.e., using data-supported empirical, analytical, and/or numerical investigative tools), that the proposed dewatering activity will not adversely impact active off-site wells or other water resources (e.g., creeks and wetlands) within 1,000 feet of the proposed dewatering pit boundary. Consistent with the Off-Channel Mining Plan (OCMP) EIR, an effect shall be considered adverse if the reduction in simulated groundwater levels exceeds two feet at any well located within 1,000 feet of the pit boundary or results in well failure.
Prior to and for the duration of dewatering activities, the applicant shall: (1) monitor water levels in the wet pit(s) and nearby monitoring wells on a quarterly basis; and (2) quantify the amount of water pumped from and returned to the wet pit(s). This monitoring data shall be reviewed by the applicant's Professional Engineer or Professional Geologist to determine whether any adverse impacts are occurring. Documentation of the monitoring and data evaluation shall be submitted to the County annually. If adverse impacts are found to be occurring, dewatering activities will be modified to eliminate adverse impacts, or the applicant shall otherwise mitigate impacts to the satisfaction of the County. Any measures designed to mitigate adverse impacts identified after implementation of dewatering activities shall be approved by the Planning Commission at a regularly scheduled meeting, with written notice of the adverse impact and proposed mitigation measures given by mail to all property owners within 1,000 feet of the pit boundary in addition to any notice otherwise required by law.
CEMEX submitted a site-specific hydrogeologic analysis, prepared by Dr. Andrew Kopania of EMK Environmental, Inc., as a part of the application package. The analysis considers the potential for the dewatering activities to impact offsite wells within 1,000 feet of the dewatering pit boundary and considers potential impacts on other water resources, includes creeks and wetlands, and on water quality.
The applicant-provided site-specific analysis was peer-reviewed by County staff and the Cache Creek Technical Advisory Committee’s Hydraulic Engineer to verify that the analysis demonstrates that the dewatering would not result in off-site impacts to groundwater or other water resources (e.g., creeks or wetlands). Following review of the site-specific analysis, and based on the concurrence of the County's Hydraulic Engineer, staff has determined the proposed dewatering request is consistent with Section 10-4.412 of the Off-Channel Surface Mining Ordinance.
CEQA Requirements
An Addendum to the CEMEX Long-Term Mining Permit Application EIR (SCH #96012034) certified November 25, 1996, has been prepared in accordance with CEQA Guidelines Section 15164 (Attachment B). CEQA Guidelines Section 15164 provides that the Lead Agency “shall prepare an Addendum to a previously certified EIR if some changes or additions are necessary, but none of the conditions described in Section 15162 calling for preparation of a subsequent EIR have occurred.” The conditions in Section 15162, which would trigger the preparation of a supplemental or subsequent EIR, include substantial changes in the project or the circumstances under which the project is undertaken that result in new significant environmental effects, or new information showing new significant environmental effects, among others. County staff determined that none of the conditions in Section 15162 were triggered by the requested amendments to the permit. Pursuant to Section 15164(e) a brief explanation is provided herein documenting the County’s decision that preparation of a subsequent EIR is not required.
The analysis provided in this document demonstrates that circumstances, impacts, and mitigation requirements identified in the CEMEX EIR remain substantively unchanged by the request to conduct pit-to-pit transfer of mine dewatering. As shown in Exhibit C, an Addendum is the appropriate level of environmental analysis. This does not remove the requirement for the applicant to continue monitoring and reporting (1) the water levels in the pits and nearby monitoring wells on a quarterly basis, and (2) quantify the amount of water pumped from and returned to the wet pits, which are requirements of the County ordinance.
CEMEX is currently mining Phase 4 of their approved mining plan using a combination of conventional excavator and an electric clamshell dredge and has already started to backfill the west side of Phase 4 for reclamation to agriculture (see Attachment A for Phase 4 mining location). Since 2021, CEMEX has worked to excavate clay below the groundwater table using the dredge so that the resources beneath the clay layers can be mined. However, the excavators cannot fully remove the clay layer to access the mineral resources below the clay and water. This results in CEMEX being unable to fully excavate the area to the permitted mining depth, leaving valuable aggregate resources in portions of the Phase 4 mining area. Yolo County's Cache Creek Area Plan, the governing plans and ordinances that regulate the County's mining program, encourages mining activities to excavate aggregate resources to the deepest extent possible to minimize the size of the mining footprint and have the least impact to agriculture. Utilizing excavators to wet mine also results in increased safety hazards such as submerged working platforms and unstable footing next to water. For example, in 2022, an excavator lost footing in the Phase 4 pit and the excavator sank to the bottom of the pond. This incident was investigated/monitored by several state and federal agencies and the excavator was removed under federal supervision to ensure there was no impact to groundwater resources.
The proposed dewatering consists of a pit-to-pit transfer of water from Phase 5 to Phase 4. The water then recharges back into the aquifer or could be used to irrigate on-site agriculture. The proposed dewatering from Phase 5 to Phase 4 would allow CEMEX to mine the areas using conventional equipment to remove the middle clay layers and mine to the full permitted depth of the sand and gravel deposits.
CEMEX requests that some of the water pumped from Phase 5 be used for onsite agricultural irrigation. Sagara Farms began the process of re-leveling the Phase 1 field for reclamation to agriculture in 2021 and planted crops in 2022. The water is proposed to be used to irrigate Sagara Farm crops in the newly reclaimed agricultural field.
Analysis
In 2017 the Board of Supervisors amended the Off-Channel Mining Ordinance to allow dewatering for mining activities with Planning Commission approval pursuant to sections 10-4.506 and 10-4.602 of Yolo County Code. Per the amended ordinance, no off-channel excavation shall use dewatering as a part of surface mining operations, unless site-specific technical analysis performed by a qualified Professional Engineer or Professional Geologist with experience in hydrogeology demonstrates that the proposed dewatering will not adversely affect off-site wells with respect to groundwater level and quality. Per the code, the Professional Engineer or Professional Geologist shall demonstrate, using appropriate hydrogeologic analysis (i.e., using data-supported empirical, analytical, and/or numerical investigative tools), that the proposed dewatering activity will not adversely impact active off-site wells or other water resources (e.g., creeks and wetlands) within 1,000 feet of the proposed dewatering pit boundary. Consistent with the Off-Channel Mining Plan (OCMP) EIR, an effect shall be considered adverse if the reduction in simulated groundwater levels exceeds two feet at any well located within 1,000 feet of the pit boundary or results in well failure.
Prior to and for the duration of dewatering activities, the applicant shall: (1) monitor water levels in the wet pit(s) and nearby monitoring wells on a quarterly basis; and (2) quantify the amount of water pumped from and returned to the wet pit(s). This monitoring data shall be reviewed by the applicant's Professional Engineer or Professional Geologist to determine whether any adverse impacts are occurring. Documentation of the monitoring and data evaluation shall be submitted to the County annually. If adverse impacts are found to be occurring, dewatering activities will be modified to eliminate adverse impacts, or the applicant shall otherwise mitigate impacts to the satisfaction of the County. Any measures designed to mitigate adverse impacts identified after implementation of dewatering activities shall be approved by the Planning Commission at a regularly scheduled meeting, with written notice of the adverse impact and proposed mitigation measures given by mail to all property owners within 1,000 feet of the pit boundary in addition to any notice otherwise required by law.
CEMEX submitted a site-specific hydrogeologic analysis, prepared by Dr. Andrew Kopania of EMK Environmental, Inc., as a part of the application package. The analysis considers the potential for the dewatering activities to impact offsite wells within 1,000 feet of the dewatering pit boundary and considers potential impacts on other water resources, includes creeks and wetlands, and on water quality.
The applicant-provided site-specific analysis was peer-reviewed by County staff and the Cache Creek Technical Advisory Committee’s Hydraulic Engineer to verify that the analysis demonstrates that the dewatering would not result in off-site impacts to groundwater or other water resources (e.g., creeks or wetlands). Following review of the site-specific analysis, and based on the concurrence of the County's Hydraulic Engineer, staff has determined the proposed dewatering request is consistent with Section 10-4.412 of the Off-Channel Surface Mining Ordinance.
CEQA Requirements
An Addendum to the CEMEX Long-Term Mining Permit Application EIR (SCH #96012034) certified November 25, 1996, has been prepared in accordance with CEQA Guidelines Section 15164 (Attachment B). CEQA Guidelines Section 15164 provides that the Lead Agency “shall prepare an Addendum to a previously certified EIR if some changes or additions are necessary, but none of the conditions described in Section 15162 calling for preparation of a subsequent EIR have occurred.” The conditions in Section 15162, which would trigger the preparation of a supplemental or subsequent EIR, include substantial changes in the project or the circumstances under which the project is undertaken that result in new significant environmental effects, or new information showing new significant environmental effects, among others. County staff determined that none of the conditions in Section 15162 were triggered by the requested amendments to the permit. Pursuant to Section 15164(e) a brief explanation is provided herein documenting the County’s decision that preparation of a subsequent EIR is not required.
The analysis provided in this document demonstrates that circumstances, impacts, and mitigation requirements identified in the CEMEX EIR remain substantively unchanged by the request to conduct pit-to-pit transfer of mine dewatering. As shown in Exhibit C, an Addendum is the appropriate level of environmental analysis. This does not remove the requirement for the applicant to continue monitoring and reporting (1) the water levels in the pits and nearby monitoring wells on a quarterly basis, and (2) quantify the amount of water pumped from and returned to the wet pits, which are requirements of the County ordinance.
COLLABORATIONS
Yolo County Department of Community Services, Planning Division
Yolo County Department of Community Services, Natural Resources Division
Cache Creek Technical Advisory Committee
Yolo County Department of Community Services, Natural Resources Division
Cache Creek Technical Advisory Committee
APPEALS
Any person who is dissatisfied with the decisions of this Planning Commission may appeal to the Board of Supervisors by filing a notice of appeal with the Clerk of the Board within fifteen (15) days from the date of the action. A Planning Commission Appeal Form and appeal fee immediately payable to “County of Yolo” must be submitted at the time of filing. The Board of Supervisors may sustain, modify or overrule this decision. The Planning Commission Appeal Form can be accessed at the following link: https://www.yolocounty.org/government/board-of-supervisors/clerk-of-the-board/planning-commission-appeal
Attachments
- Att. A. Site Plan and Hydrology Report
- Att. B. Addendum to EIR
- Att. C. Findings
- Att. D. Conditions of Approval
Form Review
| Inbox | Reviewed By | Date |
|---|---|---|
| Stephanie Cormier | Stephanie Cormier | 07/06/2023 05:37 PM |
| Eric May | Eric May | 07/07/2023 08:58 AM |
- Form Started By:
- ctschudin
- Started On:
- 07/03/2023 03:47 PM
- Final Approval Date:
- 07/07/2023