Yolo County Municipal Code Art. 5 Minimum, Reclamation Performance Standards: Off-Channel Operations

The general standard for the reclamation of mined lands is to restore the site to a usable condition which is readily adaptable for alternate land uses consistent with the policies of the County expressed in Article 1 of this chapter and in the General Plan, specific plans, and zoning laws.

This article sets forth minimum acceptable practices to be followed in reclamation operations to implement this general standard. These minimum acceptable standards shall be considered and discussed in every reclamation plan approved pursuant to this chapter. In addition, the minimum statewide reclamation practices and standards set forth in the Regulations shall also be considered and discussed in every reclamation plan approved pursuant to this chapter. These standards shall be followed in addition to any other conditions of approval or regulations imposed on the surface mining permit. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

Means of improving the appearance of the landscape after mining has been completed shall be assessed based on site-specific visual characteristics, site lines, and view corridors. The use and placement of berms, vegetative screens, special plant materials, grading. slopes, and contouring the sides and top surfaces of modified landforms to mimic surrounding landforms, or other measures, shall be incorporated into the mine reclamation plan as appropriate. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

The area of backfilled off-channel excavations extending below the groundwater table shall be minimized in order to reduce changes to groundwater levels and flow. Backfilled pits shall be oriented with regard to the direction of groundwater flow to prevent localized obstructions. If a backfilled off-channel excavation is proposed to penetrate either fifty (50') feet or one-half (½) into the saturated thickness of the shallow aquifer, then at least six (6) months prior to the commencement of excavation below the average high groundwater level, the applicant shall demonstrate in a manner consistent with the Technical Studies that the pit design will not adversely affect active off-site wells within one thousand (1,000) feet of the proposed pit boundary. If the application includes a series of backfilled pits, then the applicant shall also demonstrate that the cumulative effects of the multiple backfilled pits will not adversely affect groundwater flow, if there are any active off-site wells within one thousand (1,000) feet of the pit boundaries.

The applicant shall demonstrate, using MODFLOW (or a similar model of equal capability and proven reliability, as approved by the Director), that the proposed pit design would not adversely impact active off-site wells within one thousand (1,000) feet of the proposed pit boundary or result in well failure.

Average, historic low groundwater levels, which represent the condition of maximum threat to water levels in the subject well, shall be used for this simulation. If an adverse impact is identified by the MODFLOW (or other approved model) simulation, the mining and reclamation plan shall be modified or the applicant shall submit a written agreement that the well owner has agreed to relocate or redesign the well, or accept the potential impact (at no expense to the County).

Site-specific aquifer testing shall be conducted, if needed, to determine aquifer properties for the required modeling. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

Improvements, including the construction of buildings, roadways, or other public facilities proposed for construction in reclaimed mining pits shall require a geotechnical investigation of the stability of fills conducted by a Licensed Geotechnical Engineer or a Registered Civil Engineer. A report on the results and recommendations of the investigation shall be submitted to the Director prior to the issuance of building permits. The recommendations of the geotechnical investigations shall be fully implemented by the applicant. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

Backfilled mining areas and slopes shall be inspected by the Director following strong seismic shaking events. Observable damage shall be reported to the landowner. If the Director determines that the damage requires repair to meet the intended use of the reclaimed land, the landowner shall perform the required repairs. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

Financial assurances for off-channel mining operations which include mining within seven hundred (700) feet of the active channel of Cache Creek shall include adequate funding for maintenance during the mining and reclamation period of any bank stabilization features approved for the mining permit. Maintenance of the bank stabilization features following the completion of reclamation shall be the responsibility of the property owners under the Cache Creek Resource Management Plan.

The condition of flood protection structures, bank stabilization measures, and the integrity of the land within the approved setback zone separating the mining areas and the creek channel shall be inspected annually by a Registered Civil Engineer and reported to the Director. The annual report shall include recommendations for remedial action for identified erosion problems. Following reclamation, the Director shall inspect the land separating the mining areas and creek channel every five (5) years. Observable damage shall be reported to the property owner. If the Director determines that damage requires repair to meet the intended performance of the separator, the property owner shall perform the required repairs. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

Upon the completion of operations, grading and revegetation shall minimize erosion and convey storm water runoff from reclaimed mining areas to natural outlets or interior basins. The condition of the land shall allow sufficient drainage to prevent water pockets or undue erosion. Stormwater drainage shall be designed so as to prevent flooding on surrounding properties and County rights-of-way.

Drainage and detention facilities within the proposed mining areas and vicinity shall be designed to prevent discharges to the wet pits and surface water conveyances (i.e., creeks and sloughs) from the twenty (20) year/one-hour storm or less. For events greater than the twenty (20) year/one-hour storm, runoff from around the perimeter of the mining areas shall be directed into surface water conveyances. Runoff from within the lowered mining area shall be directed away from wet pits to detention/infiltration areas. Drainage plans shall not rely solely on ditches and berms to direct runoff away from the wet pit. Without proper maintenance, berms and ditches may deteriorate with time and become ineffective. Drainage plans shall emphasize grading of disturbed areas that results in broad gentle slopes that drain away from the pits. Grading plans shall be reviewed by the County to evaluate compliance with drainage plan objectives prior to project approval.

In addition, a restriction shall be recorded on the deed that requires berms and ditches to be permanently maintained in a condition consistent with the final approval. The deed restriction shall require an inspection easement which allows County staff or other authorized personnel access for the inspection of berms and ditches. If the County determines that evidence of damage to those facilities exists, the County shall require that the owner have an inspection report for the property prepared by a Registered Geologist or Registered Civil Engineer. The inspection report including recommendations for corrective action, if needed, shall be submitted to the Director. The property owner shall be required to implement recommended corrective actions, if any. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

The grading of final slopes, the replacement of soil, and associated erosion control measures shall take place prior to November 1 in areas where mining has been completed. To minimize erosion, the finish grading of mining pit slopes above the average seasonal high groundwater level, with the exception of the location of designated haul roads, shall be performed as soon as practical after the mining of overburden and unsaturated aggregate resources has been completed. A drought-tolerant, weed-free mix of native grass species shall be established on slopes prior to November 1 or alternate erosion control (mulch or netting) shall be placed on exposed soil on the slopes prior to this date. Phasing of mining to minimize the length of exposed mining slopes during the rainy season is encouraged. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

Where fence row or field margin habitat previously existed, reestablish similar habitat as part of reclamation to agricultural use to replace and improve the wildlife habitat value of agricultural lands, allowing for the reestablishment of scattered native trees, shrubs, and ground covers along the margins of reclaimed fields. Reestablished habitat can be located in areas other than where it occurred originally. Restoration plans shall specify ultimate fence row or field margin locations, identify planting densities for trees and shrubs, and include provisions for monitoring and maintenance to ensure establishment. Restoration plans should be reviewed and approved by the TAC. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

Open wet pits shall be fenced with a forty-two (42") inch minimum, four (4) strand barbed wire fence or the equivalent (e.g., welded square "hog" fencing), prior to the commencement of excavation, during excavation, and during reclamation. Fencing may enclose the property of which mining is a part, the mining site, or both. In addition, signs shall be installed at the project site boundaries and access road, indicating that the excavation area is restricted. Additional security (e.g., gates with protected locks and wing fences to prevent drive-arounds) shall be provided at all vehicular routes. The fencing and gates shall be maintained throughout the mining and reclamation period after completion of reclamation. A requirement shall be recorded on the deed of the property which requires the landowner to maintain fences. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

Reclaimed agricultural surfaces shall be graded to provide adequate field gradients to allow surface/furrow irrigation of crops and allow for adequate storm water drainage. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

The operator shall retain a Licensed Land Surveyor or Registered Civil Engineer to resurvey any areas reclaimed to agricultural usage after the first two (2) crop seasons have been completed. Any areas where settling has occurred shall be releveled to the field grade specified in the approved reclamation plan. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

New development proposed within the reclamation plan (such as buildings, levees, or dikes) located within the floodplain shall conform to all applicable requirements of the Yolo County Flood Protection Ordinance, and the Federal Emergency Management Agency (FEMA). (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

All reclamation plans shall be consistent with applicable components of the Yolo Habitat Conservation Plan/Natural Community Conservation Plan (HCP/NCCP). (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

Proposed habitat restoration or mitigation plans for lands within the OCMP area shall be sent to the California Department of Fish and Wildlife, U.S. Fish and Wildlife Service, the U.S. Army Corps of Engineers, and other interested parties for review and comment through the CEQA process as applicable, to ensure that the projects do not conflict with other existing habitat enhancement efforts. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

The final distance between lowered surfaces reclaimed to agriculture and the average high groundwater shall not be less than five (5') feet. The average high groundwater level shall be established for each proposed mining area. The degree of groundwater level fluctuation varies with location throughout the basin and within relatively small areas (proposed mining sites). The determination of the average high groundwater level shall be conducted by a Registered Civil Engineer or Certified Hydrogeologist and shall be based on wet season water level elevation data collected at the proposed site or adjacent areas with similar hydrogeological conditions. Water level records prior to 1977 shall not be used since they would reflect conditions prior to the installation of the Indian Valley Dam. The dam caused a significant change in hydrology of the basin and data collected before its installation shall not be used in estimating current average high groundwater levels. The wells shall be adequately distributed throughout the proposed mining site to reflect spatial variation in groundwater levels and fluctuations. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

As part of each approved long-term mining plan involving wet pit mining to be reclaimed to a permanent pond, lake, or water feature, the operator shall maintain, monitor, and report to the Director according to the standards given in this section. Requirements and restrictions are distinguished by phase of operation as described below.

(a) Mercury Protocols. The Director shall issue and update as needed “Lower Cache Creek Off-Channel Pits Mercury Monitoring Protocols” (Protocols), which shall provide detailed requirements for mercury monitoring activities. The Protocols shall include procedures for monitoring conditions in each pit lake, and for monitoring ambient mercury level in the lower Cache Creek channel within the CCAP planning area, as described below. The Protocols shall be developed and implemented by a qualified aquatic scientist or equivalent professional acceptable to the Director. The protocols shall identify minimum laboratory analytical reporting limits, which may not exceed the applicable response threshold identified in subsection (e) below. Data produced from implementing the Protocols shall meet or exceed applicable standards in the industry.

(b) Ambient Mercury Level. The determination of the ambient or “baseline” fish mercury level shall be undertaken by the County every ten (10) years in years ending in 0. This analysis shall be undertaken by the County for use as a baseline of comparison for fish mercury testing conducted in individual wet mining pits. The work to establish this baseline every ten (10) years shall be conducted by a qualified aquatic systems scientist acceptable to the Director and provided in the form of a report to the Director. It shall be paid for by the mining permit operators on a fairshare basis. The results of monitoring and evaluation of available data shall be provided in the report to substantiate the conclusions regarding ambient concentrations of mercury in fish within the lower Cache Creek channel within the CCAP planning area.

(c) Pit Monitoring.

(1) Mining Phase (including during idle periods as defined in SMARA). The operator shall monitor fish and water column profiles in each pit lake once every year during the period generally between September and November for the first five (5) years after a pit lake is created. Fish monitoring should include sport fish where possible, together with other representative species that have comparison samples from the creek and/or other monitored ponds. Sport fish are defined as predatory, trophic level four fish such as bass, which are likely to be primary angling targets and have the highest relative mercury levels. The requirements of this subsection apply to any pit lake that is permanently wet and navigable by a monitoring vessel. If, in the initial five (5) years after the pit lake is created, the applicable response threshold identified in subsection (e) is exceeded in any three (3) of five (5) monitoring years, the operator shall, solely at their own expense, undertake expanded analysis pursuant to subsection (f) and preparation of a lake management plan pursuant to subsection (g).

(2) Reclamation Phase. No monitoring is required after mining has concluded, during the period that an approved reclamation plan is being implemented, provided reclamation is completed within the time specified by SMARA or the project approval, whichever is sooner.

(3) Post-Reclamation Phase. After reclamation is completed, the operator shall monitor fish and water column profiles in each pit lake at least once every two (2) years during the period of September-November for ten (10) years following reclamation. Monitoring shall commence in the first calendar year following completion of reclamation activities. If fish monitoring results from the post-reclamation period exceed the applicable response threshold described in subsection (e) or, for ponds that have implemented mitigation management, results do not exhibit a general decline in mercury levels, the operator shall, solely at their own expense, undertake expanded analysis pursuant to subsection (f) and preparation of a lake management plan pursuant to subsection (g).

(4) Other Monitoring Obligation. If monitoring conducted during both the mining and post- reclamation phase did not identify any exceedances of the ambient mercury level for a particular pit lake, and at the sole discretion of the Director no other relevant factors substantially support that continued monitoring is merited, the operator shall have no further obligations.

(d) Reporting.

(1) Pit Monitoring Results. Reporting and evaluating of subsection (c) pit monitoring results shall be conducted by a qualified aquatic scientist or equivalent professional acceptable to the Director. Monitoring activities and results shall be summarized in a single report (addressing all wet pit lakes) and submitted to the Director within six (6) months following each annual monitoring event. The report shall include, at a minimum: (1) results from subsection (b) (pit monitoring), in relation to subsection (a) (ambient mercury levels).

(2) Expanded Analysis Results. Reporting and evaluation of subsection (f) expanded analysis shall be conducted by a qualified aquatic scientist or equivalent professional acceptable to the Director. Results shall be summarized in a single report (addressing all affected wet pit lakes) and submitted to the Director within six (6) months following each annual monitoring event. The report shall include, at a minimum, the results of the expanded analysis undertaken pursuant subsection (f).

(3) Data Sharing. For pit lakes open to the public, the Director may submit the data on mercury concentrations in pit lake fish to the state Office of Environmental Health Hazard Assessment (or its successor) for developing site-specific fish consumption advisories.

(e) Response Thresholds.

(1) Fish Consumption Advisory. If at any time during any phase of monitoring the pit lake’s average sport fish tissue mercury concentration exceeds the Sport Fish Water Quality Objective, as it may be modified by the state over time (as of 2019, the level was 0.2 mg/kg), the operator shall post fish consumption advisory signs at access points around the lake and around the lake perimeter. Catch-and-release fishing may still be allowed. Unless site-specific guidance has been developed by the state’s Office of Health Hazard Assessment or the County, statewide fish consumption guidance shall be provided.

(2) Mining Phase Results. If, during the mining phase of monitoring, the pit lake’s average fish tissue mercury concentration exceeds the ambient mercury level for any three (3) of five (5) monitoring years, annual monitoring shall continue for an additional five (5) years, and the operator shall undertake expanded analysis pursuant to subsection (f) and preparation of a lake management plan pursuant to subsection (g).

(3) Post-Reclamation Phase Results. If during the first ten (10) years of the post-reclamation phase of monitoring, the pit lake’s average fish tissue mercury concentration exceeds the ambient mercury level for any three (3) of five (5) monitoring years, biennial monitoring shall continue for an additional ten (10) years, and the operator shall undertake expanded analysis pursuant to subsection (f) and preparation of a lake management plan pursuant to subsection(g).

(f) Expanded Analysis.

(1) General. If during the mining or post-reclamation phase, any pit lake’s average fish tissue mercury concentration exceeds the ambient mercury level for any three (3) years, the operator shall undertake expanded analyses. The analysis shall include expanded lake water column profiling (a minimum of five (5) profiles per affected wet pit lake plus one or more nonaffected lakes for control purposes) conducted during the warm season (generally May through October) in an appropriate deep profiling location for each pit lake. The following water quality parameters shall be collected at regular depth intervals, from surface to bottom of each lake, following protocols identified in subsection (a): temperature, dissolved oxygen, conductivity, pH and oxidation-reduction potential (ORP), turbidity or total suspended solids, dissolved organic matter, and algal density by Chlorophyll or Phycocyanin. The initial analysis shall also include one-time collections of fine grained (clay/silt) bottom sediments from a minimum of six (6) well distributed locations for each affected lake, and from one or more nonaffected lakes for control purposes, to be analyzed for mercury and organic content.

(2) Scope of Analysis. The purpose of the expanded analyses is to identify and assess potential factors linked to elevated methylmercury production and/or bioaccumulation in each pit lake. The scope of the expanded analyses shall include monitoring and analysis appropriate to fulfill this purpose, invoking best practices in the industry. In addition to the analyses described in subsection (f)(1) above, the analysis should also consider such factors as: electrical conductivity, bathymetry (maximum and average depths, depth-to-surface area ratios, etc.), and trophic status indicators (concentrations, Secchi depth, chlorophyll a, fish assemblages, etc.). Additional types of testing may be indicated and appropriate if initial results are inconclusive.

(3) Use of Results. The results of the expanded analyses undertaken pursuant to this subsection shall be used to inform the preparation of a lake management plan described below under subsection (g).

(g) Lake Management Activities.

(1) General. If monitoring conducted during the mining or post-reclamation phases triggers the requirement to undertake expanded analysis and prepare and implement a lake management plan, the operator shall implement lake management activities designed by a qualified aquatic scientist or equivalent professional acceptable to the Director, informed by the results of subsection (f). Options for addressing elevated mercury levels may include (A) and/or (B) below at the Director’s sole discretion and at the operator’s sole expense.

(A) Lake Management Plan. Prepare a lake management plan that provides a feasible, adaptive management approach to reducing fish tissue mercury concentrations to at or below the ambient mercury level. Potential mercury control methods could include, for example: addition of oxygen to or physical mixing of anoxic bottom waters; alteration of water chemistry (modify pH or organic carbon concentration); and/or removal or replacement of affected fish populations. The lake management plan may be subject to external peer review at the discretion of the Director. Lake management activities shall be appropriate to the phase of the operation (e.g., during mining or post-reclamation). The Lake Management Plan shall include a recommendation for continued monitoring and reporting. All costs associated with preparation and implementation of the lake management plan shall be solely those of the operator. Upon acceptance by the Director, the operator shall immediately implement the plan. The lake management plan shall generally be implemented within three (3) years of reported results from the expanded analyses resulting from subsection (f). If lake management does not achieve acceptable results and/or demonstrate declining mercury levels after a maximum of three (3) years of implementation, at the sole discretion of the Director, the operator may prepare an alternate management plan with reasonable likelihood of mitigating the conditions.

(B) Revised Reclamation Plan. As an alternative to (A), or if (A) does not achieve acceptable results and/or demonstrate declining mercury levels after a maximum of three (3) years of implementation, at the sole discretion of the Director, the operator shall prepare and submit revisions to the reclamation plan (including appropriate applications and information for permit amendment) to fill the pit lake with suitable fill material to a level no less than five (5) feet above the average seasonal high groundwater level, and modify the end use to agriculture, habitat, or open space at the discretion of the Director, subject to Article 6 of the Mining Ordinance and/or Article 8 of the Reclamation Ordinance as may be applicable.

(2) Implementation Obligations.

(A) If a lake management plan is triggered during the mining or post- reclamation phase and the subsequent lake management activities do not achieve acceptable results and/or demonstrate declining mercury levels, the operator may propose different or additional measures for consideration by the Director and implementation by the operator, or

the Director may direct the operator to proceed to modify the reclamation plan as described in subsection (g)(1)(B).

(B) Notwithstanding the results of monitoring and/or lake management activities during the mining phase, the operator shall, during the post-reclamation phase, conduct the required ten (10) years of biennial monitoring.

(C) If monitoring conducted during the post-reclamation phase identifies three (3) monitoring years of mercury concentrations exceeding the ambient mercury level, the operator shall implement expanded analyses as in subsection (f), to help prepare and implement a lake management plan and associated monitoring.

(D) If subsequent monitoring after implementation of lake management activities, during the post-reclamation phase, demonstrates levels of fish tissue mercury at or below the ambient mercury level for any three (3) monitoring years (i.e., the management plan is effective), the operator shall be obligated to continue implementation of the plan and continue monitoring, or provide adequate funding for the County to do both, in perpetuity. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

Once the reclamation plan or any portion thereof has been completed, no further surface mining operations shall be allowed within reclaimed lands, without approval of an amendment to the surface mining permit and reclamation plan. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

The use of motorized watercraft on any pond, lake or other body of water created as a part of the approved reclamation plan is prohibited. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

Operational areas and haul roads that are not required for future use of the site shall be ripped, resoiled, and prepared accordingly, to allow for replanting. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

Reclamation plans shall be developed to be consistent with, avoid conflict with, and further the goals of the Cache Creek Parkway Plan. (Ord. 1518, eff. February 13, 2020)

Upon completion of reclamation within each phase of the project, for land that will not be dedicated or deeded to the County, the operator shall enroll each parcel reclaimed to agriculture in Williamson Act contract, or other equivalent long-term easement or deed restriction satisfactory to the County, for the purpose of protecting the agricultural use of the reclaimed land in perpetuity. (Ord. 1518, eff. February 13, 2020)

There shall be no permanent piles of mine waste and/or overburden. Berms established for visual screening and noise abatement shall be contoured to conform visually with the surrounding topography. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

All proposed mining and reclamation plans shall present a phasing plan for mining and reclamation activities. The phasing plan shall be structured to minimize the area of disturbed agricultural lands during each mining phase, and encourage the early completion of the reclamation of agricultural land. (§ 1, Ord. 1191, eff. September 5,1996; as amended by Ord. 1518, eff. February 13, 2020)

Site-specific planting plans shall be developed by a qualified biologist for proposed habitat reclamation projects. Restoration components of reclamation plans shall include provisions to enhance habitat for special-status species, where feasible.

Native-planted hedgerows and other vegetated buffers shall be included between restored habitat areas and adjoining farmland, in order to minimize the potential for riparian areas to serve as harbors for predators and insect pests. These buffers will also reduce the noise, dust, and spraying generated by agricultural operations, in addition to providing valuable pollinator resources that in turn could enhance agricultural production. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

Monitoring during the mining and reclamation period shall be a condition of the permit. The applicant shall ensure that the groundwater monitoring of wet-pit mining continues for (10) years after the completion of reclamation. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

All mining permit applications shall identify the location and acreage of prime farmlands, unique farmland, and farmland of statewide significance, as shown on the State Farmland Mapping and Monitoring Program (FMMP) which, as a result of reclamation, would be permanently converted to non- agricultural uses. For each acre of farmland in these categories that would be converted to non-agricultural use, the reclamation plan shall present provisions to offset the conversion of these lands, at a ratio consistent with Section 8-2.404 (Agricultural Conservation and Mitigation Program) of the County Code. This mitigation requirement may be satisfied using a variety of flexible options identified below so long as the total acreage of benefit is found to be equivalent to the applicable ratio and acreage required under Section 8-2.404 of the County Code, by type and amount of farmland being impacted, and so long as a minimum ratio of 1:1 of permanently protected agriculture land of equivalent or better quality/capability is achieved.

(a) Implementation of improvements, identified by a qualified soil scientist, to the agricultural capability of non-prime lands within the project site or outside the project site but within the OCMP area, that convert non-prime to prime agricultural conditions. These improvements can include permanent improvement of soil capability through soil amendments, reduction of soil limitations (such as excessive levels of toxins), or improvements in drainage for areas limited by flooding or low permeability soils.

(b) Placement of permanent conservation easements on land of equal or better quality/capability. The operator shall be encouraged to target property "at risk" of conversion to non-agricultural uses in selecting areas for permanent protection. Prior to approval of the conservation easement, the operator shall consult with the County and/or an appropriate non-profit agency to determine the relative risk of conversion, to which the proposed property might otherwise be subject. A minimum ratio of 1:1 is required in this category.

(c) Dedication of land, funding, or equivalent improvements, consistent with the County’s net gains goals, above and beyond the net gains benefits otherwise required under the CCAP

program.

(d) Dedication of land, funding, or equivalent improvements, consistent with the Parkway Plan, above and beyond net gains benefits otherwise required under the CCAP program. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

The cost of implementing recommendations for repair of reclaimed land caused during earthquakes or other natural events shall be met through application of contingency costs provided for by the project's financial assurances as required by SMARA. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

If any permanent wet pit is proposed to be reclaimed for recreational uses and/or riparian habitat, the design shall account for fluctuations in the groundwater table. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

The use of off-channel wet pits for the storage and treatment of sewage effluent, or for landfill purposes, is prohibited. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

All permanent wet pits shall be reclaimed to include valuable wildlife habitat as a beneficial use of the water lost from wet pits due to evaporation. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

All final reclaimed slopes shall have a minimum safety factor equal to or greater than the critical gradient as determined by an engineering analysis of the slope stability. Final slopes less than five (5') feet below the average summer low groundwater level shall be designed in accordance with the reclaimed use and shall not be steeper than 2:1 (horizontal:vertical). Reclaimed wet pit slopes located five (5') feet or more below the average summer low groundwater level shall not be steeper than 1:1 (horizontal:vertical), in order to minimize the effects of sedimentation and biological clogging on groundwater flow, to prevent stagnation, and to protect the public health.

The maximum slope angle for all final reclaimed slopes shall be determined by slope stability analysis performed by a Licensed Geotechnical Engineer or Registered Civil Engineer and submitted with any mining and reclamation application for review by the Director. The slope stability analysis shall conform with industry standard methodologies regarding rotational slope failures under static and pseudostatic (seismic) conditions. The minimum factor of safety for all design reclamation slopes located adjacent to levees or below existing structures shall not be less than 1.5 for static and 1.1 for pseudostatic (seismic) conditions. Other reclamation slopes shall meet a minimum factor of safety that is consistent with the post-reclamation use proposed for the mining area. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

Where areas are to be reclaimed to agricultural usage, all A and B horizon soil shall be ripped to a depth of three (3') feet after every two (2') foot layer of soil is laid down, in order to minimize compaction. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

Sediment fines associated with processed in-channel aggregate deposits (excavated as a result of maintenance activities performed in compliance with the CCIP) may be used in the backfill or reclamation of off-channel permanent lakes, for in-channel reshaping or habitat restoration, and/or as a soil amendment in agricultural fields provided the operator can demonstrate that no detrimental sediment toxicity exists (consistent with the state’s Stream Pollution Trends Monitoring Program protocols) and fine-grained soil (<63 micron) do not exceed 0.4 mg/kg total mercury.

The operator shall use overburden and processing fines whenever possible to support reclamation activities for pit lakes. If topsoil (A-horizon soil), formerly in agricultural production, is proposed for use within a pit lake or its drainage area, the operator must sample the soils prior to placement and analyze them for pesticides and herbicides (EPA Methods 8141B and 8151A, or equivalent) as well as for total mercury (EPA Method 7471B, or equivalent). The operator shall collect and analyze samples in accordance with EPA Test Methods for Evaluating Solid Waste Physical/Chemical Methods, SW-846 (as updated). Topsoil that contains pesticides or herbicides above the Maximum Contaminant Levels for primary drinking water (California Code of Regulations), or that contains fine-grained soils exceeding on average 0.4 mg/kg total mercury shall not be placed in areas that drain to the pit lakes.

Land reclaimed to a subsequent use that includes planting of vegetation (e.g., agriculture, habitat) shall be provided an adequate soil profile (i.e., depth and texture of soil) to ensure successful reclamation. At the discretion of the Director and at the operator’s sole expense, the proposed reclamation plan for the project may be peer reviewed by an appropriate expert/professional, and recommendations, if any, shall be incorporated into the project as conditions of approval. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

Off-channel excavations that are proposed to be reclaimed to permanent lakes shall include riparian and/or wetland habitat. The creation of riparian and/or wetland habitat along the perimeter of permanent lakes shall include appropriate features such as: scalloped basin perimeters with extended peninsulas, islands, and stepped benches of various widths at approximately three (3') foot vertical intervals both above and below the groundwater level. Where wetlands are not proposed, either grassland and/or woodland habitat, or agricultural fields separated from the lake by a berm, shall be established using only native species in order to provide continuous habitat value around the permanent lakes. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)

Where an operator demonstrates to the lead agency that an exception to the standards specified in this article is necessary, the Commission may approve an alternative standard for inclusion in the approved reclamation plan. Exceptions shall only be approved where the strict application of the off-channel reclamation standards would deprive the operator of privileges enjoyed by other mining operators in the vicinity, due to special circumstances associated with the subject site, including size, shape, topography, location, or surroundings. Although the Commission may set alternative standards, in no case may the Commission set any standard which does not meet or exceed the policy objectives set forth in the OCMP. (§ 1, Ord. 1191, eff. September 5, 1996; as amended by Ord. 1518, eff. February 13, 2020)