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Home My WebLink AboutCUP 2021-0013; PARK DRIVE STREET AND DRAINAGE IMPROVEMENTS; CONCEPTUAL OFF-SITE MITIGATION PLAN; 2021-07-01Conceptual Off-Site Mitigation Plan for Coastal Sage Scrub Habitat Impacts for the Park Drive Slope and Drainage Improvement Project at The Crossings at Carlsbad Golf Course, Carlsbad, California Prepared for: City of Carlsbad 1635 Faraday Avenue Carlsbad, California 92008 Contact: Danny Zimmy Prepared by: 605 Third Street Encinitas, California 92024 Contact: Douglas Gettinger JULY 2021 DUDEK 11632 i July 2021 Table of Contents SECTION PAGE NO. ACRONYMS AND ABBREVIATIONS ............................................................................................................................. III 1 INTRODUCTION ............................................................................................................................................. 1 1.1 Project Description and History ............................................................................................................. 1 1.2 Project Location ...................................................................................................................................... 2 1.3 Habitat Restoration Biologist ................................................................................................................. 3 1.4 Habitat Restoration Landscape Contractor .......................................................................................... 3 1.5 Nursery and Seed Supplier .................................................................................................................... 3 1.6 Existing Conditions of the Enhancement Area – Site Conditions, Soil Test Data, Transect Data ......................................................................................................................................... 3 2 PROPOSED ENHANCEMENT MEASURES ...................................................................................................... 7 2.1 Soil Amendments ................................................................................................................................... 7 2.2 Irrigation System Reactivation ............................................................................................................... 8 2.3 Pre-Planting Weed Control ..................................................................................................................... 8 2.4 Planting and Seeding ............................................................................................................................. 8 3 SUCCESS STANDARDS ................................................................................................................................ 11 4 MAINTENANCE ............................................................................................................................................ 13 4.1 Pest Management ............................................................................................................................... 13 4.2 Irrigation ............................................................................................................................................... 14 5 MONITORING .............................................................................................................................................. 15 5.1 Qualitative Monitoring ......................................................................................................................... 15 5.2 Quantitative Monitoring ...................................................................................................................... 15 5.3 Annual Reports .................................................................................................................................... 15 6 CONTINGENCY MEASURES ......................................................................................................................... 17 7 REFERENCES .............................................................................................................................................. 19 APPENDIX A Soil Test Results FIGURES 1 Project Location ................................................................................................................................................ 21 2 Project and Mitigation Area Locations Map .................................................................................................... 23 3 Mitigation Area Map .......................................................................................................................................... 25 4 Photo Views of the Mitigation Area .................................................................................................................. 27 DUDEK CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 ii July 2021 TABLES 1 Enhancement Area Soil Amendments ................................................................................................................ 7 2 Enhancement Area Container Plant List ............................................................................................................. 9 3 Enhancement Area Seed List .............................................................................................................................. 9 DUDEK 11632 iii July 2021 Acronyms and Abbreviations Acronym/Abbreviation Definition City City of Carlsbad project Park Drive Slope and Drainage Improvement Project SAR sodium adsorption ratio The Crossings The Crossings at Carlsbad Golf Course DUDEK CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 iv July 2021 INTENTIONALLY LEFT BLANK DUDEK 11632 1 July 2021 1 Introduction 1.1 Project Description and History The City of Carlsbad (City) is planning to repair and stabilize a failing hillside along Park Drive to address public safety and coastal access issues. To help mitigate for coastal sage scrub impacts associated with the Park Drive Slope and Drainage Improvement Project (project), the City is required to provide for 0.66 acres of off-site mitigation creation within the Coastal Zone. The habitat mitigation is also required to include the transplanting of nine California adolphia (Adolphia californica) plants that will be impacted by project construction. The off-site mitigation will occur at The Crossings at Carlsbad Golf Course (The Crossings), northwest of the intersection of Palomar Airport Road and College Boulevard, approximately 1.75 miles from the project site (Figure 1, Project Location; Figure 2, Project and Mitigation Area Locations Map; Figure 3, Mitigation Area Map). Both the impact and receptor sites are within the Coastal Zone. The specific language of the mitigation measure (MM-BIO-1) from the Biological Resources Technical Report for the Park Drive Slope and Drainage Improvement Project is provided below (Dudek 2020): MM-BIO-1 Habitat Mitigation: Impacts to 0.33 acres of coastal sage scrub requires mitigation at a 2:1 ratio, totaling 0.66 acres of coastal sage scrub. This habitat mitigation shall be achieved by conserving 0.66 acres of suitable habitat in an off-site mitigation area within the Coastal Zone (see Table 4, Impact and Mitigation Summary [note: table numbering maintained from source]). The habitat mitigation shall include the transplanting of California Adolphia (Adolphia californica) to the off-site creation site. The applicant shall prepare a conceptual mitigation plan and submit to the City of Carlsbad and/or Agencies for review. The final plan shall be submitted at least 30 days prior to initiating Project impacts. The mitigation shall be prepared and implemented consistent with Volume II, Appendix C (Revegetation Guidelines), and Vol. III of the North County Multiple Habitat Conservation Program; pages F-8 to F-11 of the City of Carlsbad Habitat Management Plan; and Section 3.1.5 of the Open Space Management Plan. The mitigation plan shall, at a minimum, include an evaluation of restoration suitability specific to proposed habitat types, soil and plant material salvage/translocation, planting and seeding lists, discussion of irrigation, maintenance and monitoring program, and success criteria. All areas shall be monitored for a minimum of 5 years to ensure establishment of intended plant communities. Any invasive removal associated with the coastal sage scrub creation site shall be completed using hand equipment and removal shall be completed outside of the nesting bird season. If invasive removal cannot be completed outside of the nesting bird season, pre-work surveys shall be conducted per the nesting bird survey mitigation measure (MM-BIO-4). Table 4. Impact and Mitigation Summary Vegetation Community or Land Cover Existing Acreage Permanent Impacts (acres) Required Mitigation Ratio1 Required Mitigation Acreage Native Vegetation Communities Occupied Coastal Sage Scrub 3.73 0.28 2:1 0.56 DUDEK CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 2 July 2021 Table 4. Impact and Mitigation Summary Vegetation Community or Land Cover Existing Acreage Permanent Impacts (acres) Required Mitigation Ratio1 Required Mitigation Acreage Disturbed Coastal Sage Scrub 0.05 0.05 2:1 0.10 Subtotal 3.78 0.33 — 0.66 Land Covers Disturbed Habitat 0.22 0.15 — — Ornamental 1.05 0.13 — — Developed 0.24 0.10 — — Subtotal 1.51 0.38 — — Total 5.29 0.71 — 0.66 1 Per Table 6 in the Carlsbad Habitat Management Plan (City of Carlsbad 2004). Construction on The Crossings at Carlsbad Golf Course began in 2005 and was completed in 2007. To construct the golf course, approximately 12.4 acres of native upland vegetation was impacted by the project and mitigated at a 2:1 ratio through the creation of 24.8 acres of coastal sage scrub habitat. Coastal sage scrub mitigation was installed in substantial conformance with the agency-approved Revised Mitigation Plan for the Carlsbad Municipal Golf Course (P&D and HDR 2005). Installation of the coastal sage scrub mitigation was completed and accepted by the City on June 30, 2007, maintained and monitored for 5 years, and accepted by the agencies as successful. Although only 24.8 acres of created coastal sage scrub vegetation community were necessary to meet the mitigation requirements, approximately 40 acres of coastal sage scrub vegetation community was created. The coastal sage scrub mitigation area was increased to 40 acres to provide added flexibility in achieving performance standards (P&D and HDR 2005). The coastal sage scrub mitigation was created through seeding and the installation of approximately 5,000 container plants. Not all of the 40 acres was included within the City’s Habitat Management Plan under the Multiple Habitat Conservation Program. Diegan coastal sage scrub mitigation at The Crossings consisted of 40.21 non-contiguous acres of coastal sage scrub vegetation community. Of this total mitigation acreage, approximately 30 acres involved active habitat restoration. Active habitat restoration required full monitoring services, including regular qualitative evaluations, yearly quantitative transect assessments, site observation reports, and quarterly and annual reports. The remaining approximately 10 acres of passive mitigation area presently supports native vegetation that received basic weed control and was qualitatively monitored throughout the 5-year monitoring period. The proposed coastal sage scrub mitigation area for the Park Drive Slope and Drainage Improvement Project will be added to the City’s Habitat Management Plan area. 1.2 Project Location The project is centered at approximately 33°08'40" N, 117°19'18" W. The Crossings is centered at approximately 33°07'49" N, 117°18'00" W. Figures 1–3 show the project site, which is bordered by Faraday Avenue to the north, Palomar Airport Road to the south, The Crossings Road to the west, and McClellan Palomar Airport to the east. Figure 3 shows the proposed enhancement area, which is northwest of the intersection of Palomar Airport Road DUDEK CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 3 July 2021 and College Boulevard. The nine California adolphia plants will be planted in a suitable location adjacent to the enhancement area. 1.3 Habitat Restoration Biologist A habitat restoration biologist (restoration biologist) will oversee the habitat enhancement area remedial work and monitoring. The restoration biologist will oversee implementation of this enhancement plan and provide direction to the habitat restoration landscape contractor (contractor) on behalf of the City. The restoration biologist will have the following minimum qualifications: • Bachelor’s degree in biology, ecology, botany, horticulture, or a related field such as landscape architecture. • 5 years of documented experience implementing and monitoring habitat restoration projects with an emphasis on Diegan coastal sage scrub vegetation in coastal Southern California. • Although not required, a valid Pest Control Adviser License is highly recommended, as it is required by state law to make specific pest control recommendations. 1.4 Habitat Restoration Landscape Contractor A contractor with a valid California C-27 Landscape Contracting License will perform the enhancement work and maintenance. To perform this scope of work, the contractor will also possess a valid Pest Control Business License and a Qualified Applicator License (QAL). The contractor’s duties will include site preparation, repair and operation of the irrigation system, remedial planting and seeding, pest management, trash removal, vandalism repairs, and deactivating and removing the irrigation system at the successful conclusion of the enhancement effort. The contractor will work under the direction of the restoration biologist. 1.5 Nursery and Seed Supplier All container plants will be supplied by a licensed nursery specializing in growing California native plants. Potential nurseries include Tree of Life Nursery in San Juan Capistrano, Moosa Creek Nursery in Valley Center, and Native West Nursery (formerly Recon Native Plants) in San Diego. Seed will come from a seed company specializing in native California species. The contractor may also collect seed from The Crossings golf course. Seed suppliers include S & S Seeds in Camarillo and Native West Nursery in San Diego. All propagules will originate from coastal Southern California sources. 1.6 Existing Conditions of the Enhancement Area – Site Conditions, Soil Test Data, Transect Data The Crossings project site is quite varied, with eight separate soil series documented on site and 14 different mapping units (Bowman 1973). The soils range from shallow to deep, clays to loams to loamy fine sands, with varying permeability, runoff and erosion potential, different water holding capacities, and varying fertility. The soils DUDEK CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 4 July 2021 range in pH from acid to neutral to alkaline. In addition, some soils are derived from marine formations and have high salt content. There are relatively flat areas and steep slopes, facing every aspect, north, south, east, and west. This variety of conditions will naturally support different assemblages of plant species at varying densities and vigor. Diegan coastal sage scrub habitat is quite variable, and varying soil conditions play a large role in that variability. The federally listed threatened coastal California gnatcatcher (Polioptila californica californica) is known to use many of the different alliances of plants that make up what is generally referred to as coastal sage scrub habitat, as described in the Manual of California Vegetation (Sawyer et al. 2009). The soil at the proposed 1.8 acres enhancement area is mapped as Las Flores loamy fine sand, 15%–30% slopes, eroded (LeE2) (Bowman 1973). This soil is moderately steep that is eroded with rills and gullies. Rooting depth is 16 to 26 inches and has a water holding capacity of 2 to 3 inches, with water slowly available from sandy clay subsoil. Runoff is medium to rapid, permeability is very slow, and the erosion potential is moderate to high. Fertility is low to medium. The soil profile pH ranges from medium acid to neutral (5.8 to 7.3) (Bowman 1973). Should there have been any erosion rills and gullies present in the enhancement area prior to construction, they would have been filled in and smoothed out during golf course construction and are no longer present. Dudek collected composite soil samples from the proposed enhancement area, another potential enhancement area, and a nearby reference site that will also be used to translocate the nine California adolphia plants. The soil samples were sent to Wallace Labs for agricultural suitability analysis. Agricultural suitability analysis consists of tests to determine soil reaction, measured as pH; salinity, measured as ECe; concentrations of soluble salts; fertility measurements for all 15 essential nutrients; sodium; concentrations of 15 non-essential trace metals; sodium adsorption ratio (SAR); moisture content; and soil texture. The soil test results are shown in Appendix A. Soil test results at the reference site classifies the soil as a sandy loam and shows the soil is moderately acidic in soil reaction with a pH of 5.74. Salinity is low at 0.40 millimho/cm. SAR is acceptable at 2.8. Nitrogen is modest; phosphorus, potassium, zinc, and copper are moderate; and iron, manganese, and magnesium are high. Sulfur is low. Common non-essential heavy metal levels are low. Like the proposed enhancement area, the soil map lists the soil at the reference site as Las Flores loamy fine sand, 15%–30% slopes, eroded (LeE2) (Bowman 1973). Soil test results from the proposed enhancement area is classified as sandy loam. The soil is mildly alkaline in soil reaction with a pH of 7.53. Salinity is low at 0.48 millimho/cm. SAR is acceptable at 1.5. Nitrogen, phosphorus, and manganese levels are modest; zinc and sulfur are low; copper and boron are moderate; and potassium, iron, and magnesium are high. Common non-essential heavy metal levels are low (Appendix A). Any erosion rills or gullies that may have been present in this area were filled in during golf course construction. Soil test results from the other potential enhancement area is classified as a clay loam. The soil is neutral in soil reaction with a pH of 6.98. Salinity is modestly elevated at 2.35 millimho/cm. SAR is acceptable at 1.4. Nitrogen, phosphorus, and manganese are low. Iron, zinc, and boron are moderate. Potassium, copper, manganese, and sulfur are all high (Appendix A). The soil map lists the soil as loamy alluvial land-Huerhuero complex, 9%–50% slopes, severely eroded (LvF3) (Bowman 1973). Any erosion rills or gullies that may have been present in this area were filled in during golf course construction. In addition to the soil tests, Dudek collected plant cover data from two 25-meter line transects in the proposed enhancement area on May 14, 2020. The data shows that native species cover was 75%, with 89% weed species cover and 1% bare ground. The native species cover consisted of California sagebrush (Artemisia californica) at DUDEK CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 5 July 2021 37%, California brittlebush (Encelia californica) at 25%, California buckwheat (Eriogonum fasciculatum) at 12%, and California everlasting (Psuedognaphalium californicum) at 1%. Weed species cover consisted of sourclover (Melilotus indicus) at 73% cover, tecolote (Centaurea melitensis) at 9%, spiny sowthistle (Sonchus asper) at 5%, black mustard (Brassica nigra) at 1%, and scarlet pimpernel (Lysmiachia arvensis) at 1%. Finally, the proposed enhancement area is adjacent to and within occupied habitat for coastal California gnatcatcher (Figure 3), based on previous monitoring by Dudek (Dudek 2012a, 2012b). Because a portion of the enhancement area was documented to be part of coastal California gnatcatcher territory, controlling weeds and improving habitat quality in this area should directly benefit gnatcatchers. DUDEK CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 6 July 2021 INTENTIONALLY LEFT BLANK DUDEK 11632 7 July 2021 2 Proposed Enhancement Measures All enhancement measures will be overseen and monitored by a restoration biologist and performed by an experienced contractor with coastal sage scrub experience. Any work performed in or adjacent to existing habitat during the bird breeding season from February 1 through September 15 will require a nesting bird survey in accordance with mitigation measure MM-BIO-4, per the Biological Resources Technical Report for the Park Drive Slope and Drainage Improvement Project (Dudek 2020), provided below: MM-BIO-4 Nesting Bird Survey: For clearing of any other vegetation February 1 through September 15, and clearing of occupied coastal sage scrub February 1 through February 28 and August 16 through September 15, a nesting bird survey shall be conducted within the proposed impact area and a 500-foot buffer within 72 hours prior to construction. This survey is necessary to ensure avoidance of impacts to nesting raptors (e.g., red-tailed hawk [Buteo jamaicensis]) and/or birds protected by the federal Migratory Bird Treaty Act and California Fish and Game Code Sections 3503 and 3513. If any active nests are detected, the area shall be flagged and mapped on the construction plans along with a minimum of a 300-foot buffer and up to a maximum of 500 feet for raptors or listed species, and shall be avoided until the nesting cycle is complete. If construction activities— particularly clearing/grubbing, grading, and other intensive activities—stop for more than 3 days, an additional nesting bird survey shall be conducted within the proposed impact area and a 500- foot buffer before such activities can recommence. 2.1 Soil Amendments Based on the soil test results (Appendix A), soil amendments will be applied to the soil in the enhancement area to mitigate identified deficiencies and/or excesses and provide a more favorable soil environment for growth of the desired Diegan coastal sage scrub species. Based on the laboratory soil test analysis and recommendations, agricultural gypsum, triple superphosphate, ammonium sulfate, and organic soil amendment in the form of a Biotic Soil Media will be applied to the soil. The Biotic Soil Media contains recycled biodegradable fibers, biostimulants, nutritive additives, and mycorrhizal inoculum to assist with the establishment and growth of any obligate or facultative mycotrophic species. Because the enhancement area already contains significant cover from desirable native vegetation, incorporating the amendments into the soil will be impractical. Instead they will be top dressed either by hand or hydraulically with a hydroseeder. Amendments will be applied as per Table 1. Table 1. Enhancement Area Soil Amendments Material Amount per 1,000 square feet Ammonium sulfate (21-0-0) 5 pounds Triple superphosphate (0-45-0) 4 pounds Agricultural gypsum or Soil Buster pelletized gypsum 20 pounds ProPlus BioPrime Biotic Soil Media 1 pound ProPlus JumpStart 4 ounces The soil test results are also being used to inform the container plant and seed mix for the enhancement area (see Section 2.4, Planting and Seeding). The recommended container stock and seed mix favors species ecologically adapted to the soil conditions and avoids any that are poorly adapted. DUDEK CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 8 July 2021 2.2 Irrigation System Reactivation The irrigation system that was installed and used during the original plant establishment period following golf course construction will be used to establish the planting and seeding that will be done in the enhancement area. The irrigation system was deactivated in the enhancement area and the components largely left in place once the vegetation was successfully established. The irrigation system will be rehabilitated and reactivated to provide temporary irrigation for the nine translocated California adolphia plants. The habitat restoration contractor will repair and/or replace pipes and components and rehabilitate and reactivate the still-in-place but abandoned irrigation system. The contractor may prune some existing mature coastal sage scrub plants to facilitate irrigation coverage. The contractor will need to coordinate with the golf course superintendent regarding reactivation of the automatic valves and irrigation scheduling. The irrigation system is anticipated to be operated for 1 to 2 years until the new container plants and seed planted in the enhancement area are established. 2.3 Pre-Planting Weed Control Prior to applying any soil amendments, planting the container stock, and seeding the enhancement area, the habitat restoration contractor will remove any living or dead annual weeds and perform at least one grow and kill weed control cycle. Any perennial invasive weed species will be treated with the appropriate herbicide, if needed for effective control, and the aboveground biomass removed. Many perennial invasive weed species will require repeated applications of herbicide to kill them. 2.4 Planting and Seeding Container plants and seed will be planted in the enhancement area to increase native species cover and diversity. Container plant installation will be done in accordance with standard horticultural practice within a hole at least twice the diameter as the container and at the same depth. One Best-Pak 20-10-5 controlled release fertilizer packet with micronutrients, or approved equal, will be placed with each container plant following the manufacturer’s label directions. Ideally, planting and seeding will occur late in the year, September through December, to allow the maximum time to become established during the winter rainy season. Planting and seeding can occur during the spring months, if necessary, but should not occur during the summer months. The restoration biologist will work with the contractor to spot locations to plant the container stock in the enhancement area. Tables 2 and 3 show the container plant and seed lists. DUDEK CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 9 July 2021 Table 2. Enhancement Area Container Plant List Scientific Name Common Name Container Size Quantity per Acre Quantity per 1.8 Acres Artemisia californica California sagebrush 1-gallon 218 392 Eriogonum fasciculatum California buckwheat 1-gallon 68 122 Malosma laurina laurel sumac 1-gallon 6 11 Mimulus aurantiacus bush monkey-flower 1-gallon 54 97 Opuntia littoralis coast prickly-pear 1-gallon 82 148 Rhus integrifolia lemonadeberry 1-gallon 9 16 Total 437 786 Table 3. Enhancement Area Seed List Scientific Name Common Name Percent Pure Live Seed Pounds per Acre Pounds per 1.8 Acres Acmispon glaber deerweed 85 4 7.2 Artemisia californica California sagebrush 10 4 7.2 Camissonia strigulosa sandysoil suncup TBD 0.1 0.2 Croton setiger dove weed 50 0.5 0.9 Deinandra fasciculata fascicled tarweed 20 1 1.8 Encelia californica California brittlebush 25 2 3.6 Eriogonum fasciculatum California buckwheat 10 6 10.8 Eriophyllum confertiflorum golden-yarrow 25 0.5 0.9 Eschscholzia californica California poppy 85 1 1.8 Hazardia squarrosa saw-toothed goldenbush 3 1 1.8 Isocoma menziesii Menzies’ goldenbush 15 2 3.6 Lasthenia californica goldfields 50 0.5 0.9 Lupinus bicolor miniature lupine 90 3 5.4 Lupinus truncatus collared annual lupine 56 2 3.6 Malocothamnus fasciculatus Mendocino bushmallow 10 1 1.8 Mimulus aurantiacus bush monkey-flower 2 0.5 0.9 Pseudognaphalium californicum California everlasting 2 0.5 0.9 Salvia columbrae chia 65 1 1.8 Salvia mellifera black sage 40 1 1.8 Stipa lepida foothill needlegrass 65 2 3.6 Stipa pulchra purple needlegrass 75 5 9.0 Total 38.6 69.5 TBD = to be determined DUDEK CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 10 July 2021 INTENTIONALLY LEFT BLANK DUDEK 11632 11 July 2021 3 Success Standards Performance criteria have been established that will be used to determine success of the enhancement area. These criteria modify the previously approved performance criteria that were approved for The Crossings prior to project implementation. The modified performance criteria herein are derived from data collected at The Crossings golf course after successful implementation of the Revised Mitigation Plan for the Carlsbad Municipal Golf Course (P&D and HDR 2005). In essence, the existing coastal sage scrub mitigation area serves as a reference site for additional enhancement areas. Although the coastal sage scrub mitigation did not meet the precise performance goals established in the 2005 mitigation plan, implementing the mitigation plan resulted in 24.8 acres of high-quality habitat being established at the project site that is occupied by coastal California gnatcatcher and was accepted as successful. Occupation of this self-perpetuating gnatcatcher habitat serves as a better indicator of habitat success than somewhat arbitrary numerical criteria in the mitigation plan. Environmental conditions within The Crossings site are variable with regards to soil type, depth, fertility, reaction (pH), water-holding capacity, slope orientation, and steepness. All these variables influence the plant species and vegetative cover these soils will support, which logically lends itself to more flexible performance criteria than the “one size fits all” performance criteria in the original 2005 mitigation plan. The performance criteria were developed based on previous and similar coastal sage scrub habitat restoration projects in the area, as well as by collected reference data from the gnatcatcher-occupied coastal sage scrub habitat at The Crossings. The proposed performance criteria to determine success of the enhancement area are as follows (where they differ from the original mitigation plan, standards are shown in brackets): • 75% cover; the shrub layer should compromise 40% [native trees and shrubs of at least 60% cover]. • Total vegetative ground cover of at least 75%. • Native shrubs with a cover of at least 60%, with at least 40% cover provided from any combination of the following shrub species: California sagebrush, California brittlebush, California buckwheat, Menzies’ goldenbush, San Diego bush monkey-flower, black sage (Salvia mellifera). [California sagebrush cover at least 40%, native shrubs in general (not just 1 species) at least 40%]. • Weeds with a cover of no more than 10%. • 0% weed cover for perennial species listed as invasive on the California Invasive Plant Council Inventory [proposed new standard not in the original mitigation plan]. • At least 4 native species present [at least 10 native species present]. • Native shrub species will show evidence of recruitment [of at least 5 species]. Monitoring to measure the performance criteria is provided in Section 5, Monitoring. DUDEK CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 12 July 2021 INTENTIONALLY LEFT BLANK DUDEK 11632 13 July 2021 4 Maintenance The enhancement area will be maintained by the contractor for up to 5 years to control invasive weed species and establish the container stock and seed planted to improve native species cover and diversity. Landscape maintenance is anticipated to be more intensive in the first 1–3 years and then reduced in Years 4–5 after the container plants and seed become established and irrigation is discontinued. Maintenance in Years 4–5 is expected to be limited to controlling invasive weed species and removing trash and debris, if any. The restoration biologist will oversee and work with the contractor providing the maintenance, and make recommendations, as necessary. 4.1 Pest Management Weeds are expected to be the primary pest problem in the Diegan coastal sage scrub enhancement area. Weeds will be controlled so they do not prevent establishment of the intended native species. Weeds will be controlled when they are small and before they can bloom and set seed. The contractor will be required to apply seed again if weeds are not controlled in a timely manner and the native species do not become established. A timely manner is understood to be within 1 month of written direction by the restoration biologist. More frequent weed control will be performed, as necessary, to keep weeds at manageable levels. Invasive perennial exotic species, such as fennel (Foeniculum vulgare), tree tobacco (Nicotiana glauca), castor bean (Ricinus communis), saltcedar (Tamarix species), pampas grass (Cortaderia species), artichoke thistle (Cynara cardunculus), hotentot fig (Carpobrotus species), and fountain grass (Pennisetum setaceum), will be controlled. The restoration biologist may add additional species to this list if other species are observed invading the enhancement area. A combination of physical removal and herbicide treatment will likely be required to control these species. Properly timed, repeat herbicide applications are usually required for complete control of most of these hardy perennials. The contractor will refer to the herbicide label for information on proper timing and application rates for treatment. Annual weed species present in the enhancement area prior to implementation or in the region that will likely require control include mustards (Brassica nigra, Hirchfeldia incana), garland daisy (Glebionis coronaria), stinkwort (Dittrichia graveolens), sweetclover (Melilotus species), stinknet (Oncosiphon piluliferum), wild radish (Raphanus sativus), annual sowthistles (Sonchus asper, S. oleraceus), prickly lettuce (Lactuca serriola), and various non-native annual grasses. Other weed species may invade the enhancement area and could also require control. Annual weeds and grasses will be kept under control so they are not a competitive threat to establishment of the desired native species. The restoration biologist will advise the contractor as to which species to control. All applicable laws, regulations, safety precautions, and label directions must be followed when performing pest control. The contractor performing the work should consult a licensed Pest Control Adviser if specific pest control recommendations are required. All weed debris will be removed from the enhancement area and disposed of in a legal manner. The enhancement area will be kept free of the invasive exotic weed species listed in this section, and other weed species will be controlled if the restoration biologist believes they are a competitive problem interfering with the establishment of desirable species. Pampas grass, artichoke thistle, saltcedar, and other perennial invasive exotic species will be controlled throughout the 5-year monitoring period in the enhancement area. DUDEK CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 14 July 2021 Invertebrate pests and diseases are not expected to be a problem in the enhancement area. Snails could become a problem and will be controlled if necessary. Vertebrate pests such as gophers, ground squirrels, rabbits, rats, and voles could become a problem and will be addressed by the City or contractor if necessary. Should control measures become necessary, the City or contractor will follow all applicable laws, regulations, safety precautions, and label directions when performing pest control. Vertebrate pests classified as non-game mammals by the California Department of Fish and Wildlife may be taken at any time and in any manner, but game mammals have certain restrictions that must be met before they can be controlled, and a hunting license may be required. The contractor will consult a licensed Pest Control Adviser if specific pest control recommendations are required. 4.2 Irrigation The reactivated irrigation system will be operated to help establish the remedial planting and seeding within the enhancement area and for the nine salvaged California adolphia plants. An irrigation system was installed and used during the original plant establishment period following golf course construction, and then decommissioned. The system will be repaired, rehabilitated, and reactivated to establish the container plants and seed that will be planted in the enhancement area. Once the container plants and seeds planted in the enhancement area have become successfully established, the irrigation system will be decommissioned and abandoned. The irrigation system is anticipated to be used for 2–3 years, depending on how quickly the container plants, salvaged California adolphia plants, and seedlings become established and are able to survive on natural conditions. All aboveground irrigation components will be removed and either reused or disposed of in a legal manner once they are no longer needed. DUDEK 11632 15 July 2021 5 Monitoring The restoration biologist will provide monitoring and prepare reports in accordance with the enhancement plan requirements. Monitoring will incorporate both qualitative and quantitative methods. The restoration biologist will also provide maintenance recommendations to the contractor and City, as necessary, to help meet the performance criteria. 5.1 Qualitative Monitoring Qualitative monitoring will consist of making periodic site visits to assess plant health and development and maintenance needs, and make recommendations to the contractor and the City. Qualitative monitoring site visits will occur monthly in Year 1, every other month in Years 2 and 3, and quarterly in Years 4 and 5, if necessary. Qualitative monitoring will be done for both the enhancement area and the nine salvaged California adolphia plants that will be planted nearby. 5.2 Quantitative Monitoring Quantitative monitoring will consist of collecting cover data from line transects, preparing a floral species list for the enhancement area, and counting container plant mortality. Photo documentation will also be used to document vegetation development (see current photos in Figure 4, Photo Views of the Mitigation Area). Quantitative monitoring visits will occur annually in spring when the most plants are blooming and are easier to identify. Transect monitoring will be collected from four permanent 25-meter line intercept transects established within the enhancement area. Each transect will be marked with a T-post and mapped with a GPS device. Line intercept data will be collected every 0.5 meters. Cover will be calculated by native species, non-native species, and total plant cover. Species richness data will also be collected by counting all plant species growing within a 5-meter-wide belt along each transect. Photos will be taken of each transect to photo-document vegetation development. Quantitative monitoring for the nine salvaged California adolphia plants will consist of counting and photographing the live plants to determine their quantity. 5.3 Annual Reports An annual report will be prepared each year to describe progress toward meeting the success standards for the enhancement area. DUDEK CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 16 July 2021 INTENTIONALLY LEFT BLANK DUDEK 11632 17 July 2021 6 Contingency Measures Contingency measures are not expected to be required based on previous experience establishing functioning coastal sage scrub at The Crossings. Should contingency measures be required, the City will work with the resource agencies to determine an appropriate remedial action program or actions. DUDEK CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 18 July 2021 INTENTIONALLY LEFT BLANK DUDEK 11632 19 July 2021 7 References Bowman, R.H. 1973. Soil Survey, San Diego Area, California, Part 1. United States Department of the Agriculture. 104 pp. + appendices. City of Carlsbad. 2004. City of Carlsbad Habitat Management Plan for Natural Communities in the City of Carlsbad. December 1999; final approval November 2004. https://carlsbadca.prod.govaccess.org /home/showdocument?id=1600. Dudek. 2012a. Fifth Annual Coastal Sage Scrub Mitigation Monitoring Report for the Crossing at Carlsbad Golf Course, City of Carlsbad, California. May. 122.pp. Dudek. 2012b. 2012 Post-Construction California Gnatcatcher Monitoring Report for The Crossings at Carlsbad, City of Carlsbad, San Diego County, California,Permit #’s TE051248-4 and TE139634-1. May. 60 pp. Dudek. 2020. Draft Biological Resources Technical Report, Park Drive Slope and Drainage Improvement Project. December. 100 pp. P&D and HDR (P&D Environmental and HDR Engineering). 2005. Mitigation Plan Carlsbad Municipal Golf Course. February 2005. 35 pp. Sawyer, J.O., T. Keeler-Wolf, and J.M. Evens. 2009. A Manual of California Vegetation, Second Edition. California Native Plant Society, Sacramento, California. 1300 pp. DUDEK CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 20 July 2021 INTENTIONALLY LEFT BLANK DUDEK Project Location Conceptual Off-Site Mitigation Plan for Coastal Sage Scrub Habitat Impacts to the Park Drive Slope and Drainage Improvement Project SOURCE: BING MAPPING SERVICE 0 2,0001,000 Feet Project Boundary FIGURE 1 Project Site D DUDEK ! CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 22 July 2021 INTENTIONALLY LEFT BLANK DUDEK 5 KE L L Y D R PALOMARAIRPORTRD MILTONRD CANNON RD COR D O B A P L WHITMANWAY C A RLSB AD BLVD DONM IGUELDR MERWINDR ARGOSYL N NEBLINADR ALO N D R A WAY DONPA B LODR T W AIN AVE STEINBECKCT FARADAY A V E DICKINSONDR L YN CH CT FROST AVE PA L O M AR O AKS W A Y JACKSPARDR ASTONAVE CAMINOHILLSDR CARLSBAD BL V D VALE N C IA A V E CIARDICT LOMALAGUNA DR LINDSAYDR BYRON PL LONGFE L L O WRDHEMINGWAYDR AVENIDAENCIN A S B RUC E RD GR A N DPACIFICDR NEWTONDR KEAT SPL HILLSIDE D R MORGANRD VANALLENWAY HORIZONDR PARKDR CO AS T LI NEAVE A SHBE RRYRDSEVILLAWAY C OL L E G E B L V D MARBRISACIR L O S R O B L E S D R D R YD EN P L E L A R B OL D R EL CAMI N O R E A L REFUGIOAVE P ASEODELNORTE ADAMSST SU N N Y HIL L D R COVEDR TOLKIEN WAY ARMADADR H I G H LANDDR MASTERSRD PALOMARAIRPORTRD FLE E T S T C A R C OUNTRY D R LEGOLANDDR AQUA HEDIONDALAGOON Project and Mitigation Area Locations Map Conceptual Off-Site Mitigation Plan for Coastal Sage Scrub Habitat Impacts to the Park Drive Slope and Drainage Improvement Project SOURCE: SANGIS 2017, 2020 Da t e : 7 / 2 1 / 2 0 2 1 - L a s t s a v e d b y : l t e r r y - P a t h : Z : \ P r o j e c t s \ j 1 1 6 3 2 0 1 \ M A P D O C \ M I T I G A T I O N \ O f f s i t e M i t P l a n \ F i g u r e 2 - P r o j e c t a n d M i t i g a t i o n L o c a t i o n s . m x d 0 2,0001,000 Feet Project Boundary The Crossing Golf Course Boundary Offsite Mitigation at The Crossings Golf Course Alternative Enhancement Location Reference Area FIGURE 2 Mitigation Site- See Inset Left Project Site Hole 3 Hole 2Hole 7Hole 1 Hole 2 Practice AVIARAPKY PALOMARAIRPORTRD COLLEGE BLVD Alternative Enhancement Location Reference Area Mitigation Site DUDEK 6 CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 24 July 2021 INTENTIONALLY LEFT BLANK DUDEK PRACTICE AREA HOLE 2 C O L L E G E B L V D HOLE 7 Mitigation Area Map Conceptual Off-Site Mitigation Plan for Coastal Sage Scrub Habitat Impacts to the Park Drive Slope and Drainage Improvement Project SOURCE: AERIAL-SANGIS 2017Da t e : 6 / 2 9 / 2 0 2 1 - L a s t s a v e d b y : l t e r r y - P a t h : Z : \ P r o j e c t s \ j 1 1 6 3 2 0 1 \ M A P D O C \ M I T I G A T I O N \ O f f s i t e M i t P l a n \ F i g u r e 3 - M i t i g a t i o n A r e a M a p . m x d 0 12060Feet FIGURE 3 Offsite Mitigation California Adolphia Receptor Site Approximate Gnatcatcher Territory documented in 2012 by Dudek C.1 {Q) D DUDEK ~ CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 26 July 2021 INTENTIONALLY LEFT BLANK DUDEK Photo 1: View looking south. (Photo Date: 5/14/2020) Photo 3: View looking northeast. (Photo Date: 5/14/2020) DUDEK Photo 2: View looking northwest. (Photo Date: 5/14/2020) Photo 4: View looking southeast. (Photo Date: 5/14/2020) FIGURE4 Photo Views of the Mitigation Area Conceptual Off-Site Mitigation Plan for Coastal Sage Scrub Habitat Impacts to the Park Drive Slope and Drainage Improvement Project CONCEPTUAL OFF-SITE MITIGATION PLAN FOR COASTAL SAGE SCRUB HABITAT IMPACTS FOR THE PARK DRIVE SLOPE AND DRAINAGE IMPROVEMENT PROJECT AT THE CROSSINGS AT CARLSBAD GOLF COURSE, CARLSBAD, CALIFORNIA 11632 28 July 2021 INTENTIONALLY LEFT BLANK DUDEK Appendix A Soil Test Results Soil Analyses Plant Analyses Water Analyses WALLACE LABORATORIES 365 Coral Circle El Segundo, CA 90245 phone (310) 615-0116 fax (310) 640-6863 January 22, 2021 Doug Gettinger, DGettinger@dudek.com Dudek & Associates, Inc. 605 Third Street Encinitas, CA 92024 RE: The Crossings Golf Course, Job No. 11632-04-02 Received January 20, 2021, Coastal Sage Scrub Revegetation, Our ID No. 21-21-22 Dear Doug, The pH is moderately alkaline at 7.53. Salinity is modest at 0.48 millimho/cm. Nitrogen, phosphorus and manganese are modest. Zinc and sulfur are low. Copper and boron are moderate. Potassium, iron and magnesium are high. Sodium is moderate. SAR (sodium adsorption ratio) is 1.5. The concentrations of common non-essential heavy metals are low. Frequently in California, topsoils have modest amounts of magnesium and subsoils contain high levels of magnesium. High magnesium is undesirable. Magnesium limits the uptake of potassium and calcium. It acts like sodium and disperses soil crumbs. Periodic additions of gypsum can be made to reduce the effects of high magnesium. Recommendations General soil preparation on a square foot basis. Broadcast the following uniformly; rates are per 1,000 square feet for a 6-inch lift. Incorporate them homogeneously 6" deep. Ammonium sulfate (21-0-0) – 5 pounds Triple superphosphate (0-45-0) – 4 pounds Agricultural gypsum - 20 pounds Organic soil amendment - about 4 cubic yards, sufficient for 3% to 5% soil organic matter on a dry weight basis For the preparation on a volume basis, homogeneously blend the following materials into the soil. Rates are expressed per cubic yard: Ammonium sulfate (21-0-0) – 1/4 pound Triple superphosphate (0-45-0) – 1/4 pound Agricultural gypsum – 1 pound Organic soil amendment - about 20% by volume, sufficient for 3% to 5% soil organic matter on a dry weight basis Dudek & Associates, Inc., January 22, 2021, page 2 Soil Analyses Plant Analyses Water Analyses Organic soil amendment: 1. Humus material shall have an acid-soluble ash content of no less than 6% and no more than 20%. Organic matter shall be at least 50% on a dry weight basis. 2. The pH of the material shall be between 6 and 7.5. 3. The salt content shall be less than 10 millimho/cm @ 25° C. on a saturated paste extract. 4. Boron content of the saturated extract shall be less than 1.0 part per million. 5. Silicon content (acid-insoluble ash) shall be less than 50%. 6. Calcium carbonate shall not be present if to be applied on alkaline soils. 7. Types of acceptable products are composts, manures, mushroom composts, straw, alfalfa, peat mosses etc. low in salts, low in heavy metals, free from weed seeds, free of pathogens and other deleterious materials. 8. Composted wood products are conditionally acceptable [stable humus must be present]. Wood based products are not acceptable which are based on red wood or cedar. 9. Sludge-based materials are not acceptable. 10. Carbon:nitrogen ratio is less than 25:1. 11. The compost shall be aerobic without malodorous presence of decomposition products. 12. The maximum particle size shall be 0.5 inch, 80% or more shall pass a No. 4 screen for soil amending. Maximum total permissible pollutant concentrations in amendment in parts per million on a dry weight basis: arsenic 12 copper 100 selenium 20 cadmium 15 lead 200 silver 10 chromium 150 mercury 10 vanadium 50 cobalt 30 molybdenum 20 zinc 200 nickel 100 Higher amounts of salinity or boron may be present if the soils are to be preleached to reduce the excess or if the plant species will tolerate the salinity and/or boron. For site maintenance, apply ammonium sulfate (21-0-0) at 5 pounds per 1,000 square feet about once per quarter. Monitor the site with periodic soil and leaf tissue testing. Adjust the maintenance program as needed. Sincerely, Garn A. Wallace, Ph. D. GAW:n WALLACE LABS SOILS REPORT Print Date Jan. 21, 2021 Receive Date 1/20/21 365 Coral Circle Location The Crossings Golf Course, Job No. 11632-04-02 El Segundo, CA 90245 Requester Doug Gettinger, Dudek (310) 615-0116 graphic interpretation: * very low, ** low, *** moderate ammonium bicarbonate/DTPA * * * * high, * * * * * very high extractable - mg/kg soil Sample ID Number 21-21-22 Interpretation of data Sample Description Coastal Sage Scrub Revegetation low medium high elements graphic 0 - 7 8-15 over 15 phosphorus 3.61 ** 0-60 60 -120 121-180 potassium 140.08 **** 0 - 4 4 - 10 over 10 iron 12.36 **** 0- 0.5 0.6- 1 over 1 manganese 0.57 ** 0 - 1 1 - 1.5 over 1.5 zinc 0.23 * 0- 0.2 0.3- 0.5 over 0.5 copper 0.41 *** 0- 0.2 0.2- 0.5 over 1 boron 0.26 *** calcium 334.53 *** magnesium 1,077.93 ***** sodium 102.77 *** sulfur 13.52 * molybdenum 0.05 *** nickel 0.19 * The following trace aluminum 0.05 * elements may be toxic arsenic 0.11 * The degree of toxicity barium 0.28 * depends upon the pH of cadmium 0.06 * the soil, soil texture,chromium n d * organic matter, and the cobalt n d * concentrations of the lead 0.10 * individual elements as well lithium 0.05 * as to their interactions.mercury n d * selenium 0.04 * The pH optimum depends silver n d * upon soil organic strontium 1.56 * matter and clay content-tin 0.02 * for clay and loam soils:vanadium 0.14 * under 5.2 is too acidic 6.5 to 7 is ideal Saturation Extract over 8.0 is too alkaline pH value 7.53 **** The ECe is a measure of ECe (milli-0.48 ** the soil salinity: mho/cm)millieq/l 1-2 affects a few plants calcium 46.4 2.3 2-4 affects some plants,magnesium 13.2 1.1 > 4 affects many plants.sodium 45.7 2.0 potassium 5.3 0.1 cation sum 5.5 problems over 150 ppm chloride 41 1.2 good 20 - 30 ppm nitrate as N 8 0.6 phosphorus as P 0.5 0.0 toxic over 800 sulfate as S 28.4 1.8 anion sum 3.5 toxic over 1 for many plants boron as B 0.21 ** increasing problems start at 3 SAR 1.5 ** est. gypsum requirement-lbs./1000 sq. ft.291 relative infiltration rate fair estimated soil texture sandy loam lime (calcium carbonate)low organic matter low moisture content of soil 8.6% half saturation percentage 26.0% Elements are expressed as mg/kg dry soil or mg/l for saturation extract. pH and ECe are measured in a saturation paste extract. nd means not detected. Analytical data determined on soil fraction passing a 2 mm sieve. I I I I I I I I Soil Analyses Plant Analyses Water Analyses WALLACE LABORATORIES 365 Coral Circle El Segundo, CA 90245 phone (310) 615-0116 fax (310) 640-6863 March 11, 2021 Doug Gettinger, DGettinger@dudek.com Dudek & Associates, Inc. 605 Third Street Encinitas, CA 92024 RE: The Crossings Golf Course, Job No. 11632-04-02 Two samples received March 8. 2021 Dear Doug, Reference Site - The pH is acidic at 5.74. Salinity is modest at 0.40 millimho/cm. Nitrogen and boron are modest. Sulfur is low. Phosphorus, potassium, zinc and copper are moderate. Iron, manganese and magnesium are high. Sodium is moderate. SAR (sodium adsorption ratio) is 2.8. The concentrations of common non-essential heavy metals are low. Frequently in California, topsoils have modest amounts of magnesium and subsoils contain high levels of magnesium. High magnesium is undesirable. Magnesium limits the uptake of potassium and calcium. It acts like sodium and disperses soil crumbs. Periodic additions of gypsum can be made to reduce the effects of high magnesium. Revegetation Site – The pH is neutral. Salinity is modestly elevated at 2.35 millimho/cm. Soluble sulfur is high. Nitrogen, phosphorus and manganese are low. Iron, zinc and boron are moderate. Potassium, copper, magnesium and sulfur are high. Gypsum is present. Magnesium is higher than for the Reference Site. Recommendations for Revegetation Site General soil preparation on a square foot basis. Broadcast the following uniformly; rates are per 1,000 square feet for a 6-inch lift. Incorporate them homogeneously 6" deep. Calcium ammonium nitrate (27-0-0) – 4 pounds Triple superphosphate (0-45-0) – 4 pounds Organic soil amendment - about 4 cubic yards, sufficient for 3% to 6% soil organic matter on a dry weight basis For the preparation on a volume basis, homogeneously blend the following materials into the soil. Rates are expressed per cubic yard: Dudek & Associates, Inc., March 11, 2021, page 2 Soil Analyses Plant Analyses Water Analyses Calcium ammonium nitrate (27-0-0) – 1/4 pound Triple superphosphate (0-45-0) – 1/4 pound Organic soil amendment - about 20% by volume, sufficient for 3% to 6% soil organic matter on a dry weight basis Organic soil amendment: 1. Humus material shall have an acid-soluble ash content of no less than 6% and no more than 20%. Organic matter shall be at least 50% on a dry weight basis. 2. The pH of the material shall be between 6 and 7.5. 3. The salt content shall be less than 10 millimho/cm @ 25° C. on a saturated paste extract. 4. Boron content of the saturated extract shall be less than 1.0 part per million. 5. Silicon content (acid-insoluble ash) shall be less than 50%. 6. Calcium carbonate shall not be present if to be applied on alkaline soils. 7. Types of acceptable products are composts, manures, mushroom composts, straw, alfalfa, peat mosses etc. low in salts, low in heavy metals, free from weed seeds, free of pathogens and other deleterious materials. 8. Composted wood products are conditionally acceptable [stable humus must be present]. Wood based products are not acceptable which are based on red wood or cedar. 9. Sludge-based materials are not acceptable. 10. Carbon:nitrogen ratio is less than 25:1. 11. The compost shall be aerobic without malodorous presence of decomposition products. 12. The maximum particle size shall be 0.5 inch, 80% or more shall pass a No. 4 screen for soil amending. Maximum total permissible pollutant concentrations in amendment in parts per million on a dry weight basis: arsenic 12 copper 100 selenium 20 cadmium 15 lead 200 silver 10 chromium 150 mercury 10 vanadium 50 cobalt 30 molybdenum 20 zinc 200 nickel 100 Higher amounts of salinity or boron may be present if the soils are to be preleached to reduce the excess or if the plant species will tolerate the salinity and/or boron. For site maintenance, apply calcium ammonium nitrate (27-0-0) at 4 pounds per 1,000 square feet several times a year. Dudek & Associates, Inc., March 11, 2021, page 3 Soil Analyses Plant Analyses Water Analyses Monitor the site with periodic soil and leaf tissue testing. Adjust the maintenance program as needed. Sincerely, Garn A. Wallace, Ph. D. GAW:n WALLACE LABS SOILS REPORT Print Date Mar. 10, 2021 Receive Date 3/8/21 365 Coral Circle Location The Crossings Golf Course, Job No. 11632-04-02 El Segundo, CA 90245 Requester Doug Gettinger, Dudek, Encinitas (310) 615-0116 graphic interpretation: * very low, ** low, *** moderate ammonium bicarbonate/DTPA * * * * high, * * * * * very high extractable - mg/kg soil Sample ID Number 21-69-57 21-69-58 Interpretation of data Sample Description Reference Site Revegetation Site low medium high elements graphic graphic 0 - 7 8-15 over 15 phosphorus 9.26 ***6.45 ** 0-60 60 -120 121-180 potassium 100.82 ***165.37 **** 0 - 4 4 - 10 over 10 iron 22.78 *****9.19 *** 0- 0.5 0.6- 1 over 1 manganese 4.71 ****0.36 ** 0 - 1 1 - 1.5 over 1.5 zinc 1.14 ***1.03 *** 0- 0.2 0.3- 0.5 over 0.5 copper 0.47 ***0.92 **** 0- 0.2 0.2- 0.5 over 1 boron 0.17 **0.26 *** calcium 538.31 ****476.74 **** magnesium 743.93 *****1,109.89 ***** sodium 173.93 ***220.59 **** sulfur 12.06 *1,001.94 ***** molybdenum 0.04 ***0.04 *** nickel 0.42 *0.15 * The following trace aluminum n d *n d * elements may be toxic arsenic 0.28 *0.06 * The degree of toxicity barium 1.74 *0.09 * depends upon the pH of cadmium 0.04 *0.03 * the soil, soil texture,chromium n d *n d * organic matter, and the cobalt 0.11 *0.05 * concentrations of the lead 2.12 **0.31 * individual elements as well lithium 0.47 *0.56 * as to their interactions mercury n d *n d * selenium n d *n d * The pH optimum depends silver n d *n d * upon soil organic strontium 4.50 *1.25 * matter and clay content-tin n d *n d * for clay and loam soils:vanadium 0.25 *0.03 * under 5.2 is too acidic 6.5 to 7 is ideal Saturation Extract over 8.0 is too alkaline pH value 5.74 **6.98 *** The ECe is a measure of ECe (milli-0.40 **2.35 **** the soil salinity: mho/cm)millieq/l millieq/l 1-2 affects a few plants calcium 12.7 0.6 314.9 15.7 2-4 affects some plants,magnesium 7.0 0.6 94.1 7.8 > 4 affects many plants.sodium 51.0 2.2 109.9 4.8 potassium 2.6 0.1 9.5 0.2 cation sum 3.5 28.5 problems over 150 ppm chloride 28 0.8 15 0.4 good 20 - 30 ppm nitrate as N 11 0.8 1 0.0 phosphorus as P 1.4 0.0 0.3 0.0 toxic over 800 sulfate as S 22.3 1.4 461.2 28.8 anion sum 3.0 29.3 toxic over 1 for many plants boron as B 0.28 **0.31 ** increasing problems start at 3 SAR 2.8 **1.4 * est. gypsum requirement-lbs./1000 sq. ft.193 321 relative infiltration rate slow fair estimated soil texture sandy loam clay loam lime (calcium carbonate)no no organic matter low/fair low moisture content of soil 7.0%16.5% half saturation percentage 21.3%33.7% Elements are expressed as mg/kg dry soil or mg/l for saturation extract. pH and ECe are measured in a saturation paste extract. nd means not detected. Analytical data determined on soil fraction passing a 2 mm sieve. I I I I I I I I