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HomeMy WebLinkAboutCT 99-04; Villages of La Costa Oaks & Ridge; Tentative Map (CT) (17)1 1 1 1 IH Villages of La Costa J 1 1 1 1 1 1 1 1 1 1 1 1 1_ I 1 CONCEPTUAL MITIGATION PLAN August 9, 2001 Prepared for: VILLAGES OF LA COSTA 2300 Alga Road Carlsbad, California 92009 Prepared by: HELIX ENVIRONMENTAL PLANNING, INC. 8100 La Mesa Boulevard, Suite 150 La Mesa, California 91941-6476 I I I I I I I I I I I I I I I I I I I Villages of La Costa Conceptual Mitigation Plan TABLE OF CONTENTS Section Page I. INTRODUCTION 1 II. PROJECT DESCRIPTION 1 A. Project Location 1 B. Project Summary 1 C Responsible Party 2 D. Jurisdictional Areas to be Filled 2 E. Function and Value of Jurisdictional Areas to be Impacted 3 III. GOALS OF MITIGATION 4 A. Type(s) of Habitat to be Preserved, Enhanced or Created 4 B. Time Lapse 4 C. Estimated Costs 5 IV. FINAL SUCCESS CRITERIA '. 5 A. Target Functions and Values 5 B. Target Hydrological Regime 5 C. Target Jurisdictional Acreage to be Created 5 V. PROPOSED MITIGATION SITE 6 A. Location and Size of Mitigation Area 6 B. Ownership Status 6 C. Existing Functions and Values of Mitigation Area 6 D. Present and Proposed Uses of Mitigation Area 7 E. Jurisdictional Delineation (If applicable) 7 F. Present and Proposed Uses of All Adjacent Areas 7 VI. IMPLEMENTATION PLAN 7 A. Rationale for Expecting Implementation Success 7 B. Responsible Parties 8 , 1. Project Proponent 8 2. Landscape Architect 8 3. Restoration Specialist ..8 4. Installation Contractor 8 5. Maintenance Contractor 8 C. Schedule 9 D. Site Preparation 9 E. Planting Plan 10 1. Willow Riparian Scrub (including Southern Willow Scrub) 10 2. Willow Riparian Woodland 11 3. Contract Growing and Plant Material Sources 12 4. Substitutions 12 5. Plant Material Inspection 12 6. Container Plant Guarantees 12 TABLE OF CONTENTS (cont.) XI. LITERATURE CITED 19 I I I VI. IMPLEMENTATION PLAN (cont.) • E. Planting Plan (cont.) H 7. Seed Guarantees 12 8. Planting Methods 13 • 9. Timing for Installation of Plant Material : 13 | F. IRRIGATION PLAN 13 G. AS-BUILT CONDITIONS 13 • VII. MAINTENANCE DURING MONITORING PERIOD 14 A. Maintenance Activities 14 _ 1. General Maintenance 14 • 2. Irrigation : 15 * 3. Weed Control 15 4. Disease and Other Pests 15 I 5. Pruning '. 15 I B. RESPONSIBLE PARTIES 15 C SCHEDULE 16 VIII. MONITORING PLAN 16 A. Performance Criteria 16 • B. Monitoring Methods , 17 I 1. Species Diversity 17 2. Cover by Weeds 17 3. Cover by Native Species 17 I C. Annual Reports 17 ™ D. Schedule 17 IX. COMPLETION OF MITIGATION 18 | A. Notification of Completion 18 B. Agency Confirmation 18 • X. CONTINGENCY MEASURES A. Initiating Procedures 18 _ B. Alternative Locations for Contingency Mitigation 18 • C. Funding Mechanism 18 ™ D. Responsible Parties 18 I I I I I I I I I I I I I I I I I I I I I I I I I TABLE OF CONTENTS (cont.) LIST OF FIGURES Follows No. Title Page 1 Regional Location Map 2 2 Project Vicinity Map 2 3a Greens Riparian Restoration Site 4 3b Greens Riparian Enhancement Site 4 4 Oaks Riparian Restoration Site 4 LIST OF TABLES No. Title Page 1 Proposed Impacts to Jurisdictional Areas - ACOE/CDFG : 3 2 Southern Willow Scrub Plant Palette 10 3 Riparian Woodland Plant Palette , 11 4 Restoration Specialist Maintenance Monitoring Schedule 14 5 Maintenance Schedule 16 6 Annual Success Criteria Milestones for Villages of La Costa 16 111 I I I I I I I I I I I I I I I I I I I I. INTRODUCTION This report provides project information, a conceptual mitigation plan, and a monitoring program for advance mitigation of impacted jurisdictional areas within the Villages of La Costa Master Plan (VLCMP) area. The form and content of this report is based on the U.S. Army Corps of Engineers' (ACOE) Habitat Mitigation and Monitoring Proposal Guidelines (1993). II. PROJECT DESCRIPTION A. PROJECT LOCATION The VLCMP is located in the City of Carlsbad in northwestern San Diego County (Figures 1 and 2). The Master Plan area consists of two project sites that together total 1,867 acres: the 662-acre Greens project and the 1,205-acre Oaks/Ridge project. Both sites are within the habitat Conservation Plan/Ongoing Multiple Species Plan (HCP/OMSP) for properties in the Southeast Quadrant of the City of Carlsbad, California (City of Carlsbad et. al. 1995). The Greens project site is located north of Alga Road, east of El Camino Real, south of the Bressi Ranch property (Palomar Airport Road), and west of Unicornio Street (Figure 2). This property consists primarily of undeveloped land. The site drains into San Marcos Creek and Batiquitos Lagoon, approximately one mile south of the site boundary. On-site elevations range from approximately 60 feet above mean sea level (amsl) in the south to 350 feet amsl in the east. The property was formerly used for ranching and farming. Remnants of the agricultural activities on site include a house, several out buildings, ornamental plantings, and several ponds created for agricultural purposes. Other development on site includes recent sewer improvements made by the Vallecitos Water District. The Greens property surrounds the northern portion of the La Costa Country Club golf course on all sides but the south. Alga Road forms most of the sites southern border. Adjoining properties consist of undeveloped land to the north, residential developed land to the east and south, and residential and commercial developed land to the west. The undeveloped property to the north, Bressi Ranch, is proposed for future development. Open space connections are proposed to the north, east and south with adjacent properties as a part of the Habitat Management Plan for Natural Communities in the City of Carlsbad (City of Carlsbad 1999). The Oaks/Ridge property is located north of La Costa Avenue and Sitio Baya, and is bisected by Rancho Santa Fe Road (Figure 2). San Marcos Creek separates the Oaks and Ridge parcels. The northern boundary lies east of El Fuerte Street, and south of Alga Road and Xana Way. The site consists primarily of undeveloped land. On site elevations range from approximately 245 feet in the south and west to 990 feet in the east. A fire in October 1996 burned most of the site. Adjoining properties consist of residential development to the north, south and west, and undeveloped land to the east. Open space connections are proposed along portions of the southern boundary, to the west along San Marcos Creek and north of Esfera Street and existing development, and to the east (City of Carlsbad 1999). B. PROJECT SUMMARY The proposed project consists of two sites; the Greens and Oaks/Ridge together compromise 1,867 acres, Development of these properties is proposed as part of the Villages of La Costa Master Plan that will provide a total of 2,390 residential homes, community infrastructure and amenities including more than 856 acres of natural open space. HELIX Conceptual Mitigation Plan for Villages of La Costa / MDl-06 / August 9, 2001 1 I The Greens project site would provide approximately 1,038 residential homes, 10.6 acres of planned- | industrial, a 3.9-acre community facility, a 25.8-acre park site, a 6.8-acre school site, necessary circulation roads, bicycle and pedestrian trails, and approximately 215 acres of natural open space. The open space • contains most of the primary drainage on site, and a majority (90.9 acres, 75 percent) of the southern B maritime chaparral on site. Primary access to the Greens portion of the project would be from Poinsettia Lane. Secondary access is provided from Alga Road along the southern boundary of the Greens and Alicante Road, which bisects the property running north south. B The Oaks/Ridge project would provide 1,352 residential homes, a 6.4-acre community facility site, a common recreation area of at least 20 acres, a 9.6-acre SDG&E utility corridor, necessary circulation roads B (including the realignment of Rancho Santa Fe Road), bicycle and pedestrian trails, and approximately B 653 acres of natural open space. The open space includes the majority of San Marcos Creek, the primary drainage on site. An additional 85 acres has been added to the overall project area in the western portion • of the project. These additional acres are all proposed for open space. A total of 37.88 acres of wetlands | and waters of the U.S. will be preserved on site. C. RESPONSIBLE PARTY I Real Estate Collateral Management Contact: Fred Arbuckle B 1903 Wright Place, Suite 180 • Carlsbad, CA 92008 (760) 929-2701 • farbuckle@morrowdevelopment.com | D. JURISDICTIONAL AREAS TO BE FILLED _ The overall development of the Greens and Oaks/Ridge project areas would affect 5.9 acres of jurisdictional wetlands and 1.58 acres of non-wetland Waters of the U.S. The Greens portion of the project would impact approximately 5.32 acres of wetlands and 1.03 acres of B non-wetland Waters of the U.S. Jurisdictional wetland habitat affected consists of: 2.47 acres of freshwater marsh, 2.51 acres of southern willow scrub, 0.09 acre of disturbed southern willow scrub, 0.12 • acre of mule fat scrub and 0.13 acre of tamarisk scrub. Jurisdictional non-wetland Waters of the U.S. | habitats, affected by the Greens project, consists of: 0.76 acre of open water and 0.27 acre of streambed. State (CDFG) jurisdictional impacts within the boundaries of the proposed Greens development total _ approximately 6.46 acres (Table 1). CDFG jurisdictional areas include all ACOE jurisdictional wetlands B and non-wetland Waters and an additional 0.11 acre of southern willow scrub. The open space remaining on the Greens property contains most of the primary drainage on site. The proposed Oaks/Ridge portion results in impacts to approximately 0.58 acre of wetlands (freshwater B marsh) and 0.55 acre of non-wetland Waters of the U.S. (streambed). An additional 1,960 square feet of man-made, low-quality vernal pool surface area (0.045 acre) will be impacted. The vernal pools are not • considered jurisdictional. State (CDFG) jurisdictional areas include all of the ACOE jurisdictional | wetlands and non-wetland Waters of the U.S. No additional CDFG jurisdictional areas occur on site. A total of 37.88 acres of wetlands and waters of the U.S. will be preserved on site. M HELIX Conceptual Mitigation Plan far Villages of La Costa/MDI-06/August 9, 2001 I I I . . ORANGE SAN DIEGO L I /"*r"M l»IT-\y ^^ .. ^ UNITED STATES ... 'Ti "'—wixico DEUX Regional Location Map LA COSTA GREENS AND OAKS/RIDGE PROPERTIES Figure 1 Greens Restoration Area rThe Greens reens Enhancement Area the Ridge Property The Oaks Property Oaks Restoration Source: USGS 7.5min. Quadrangles; Encinitas and Rancho Santa Fe HELIX Project Vicinity Map LA COSTA GREENS AND OAKS/RIDGE PROPERTIES Figure 2 I I I I I I I I I I I I I I I I I I I Table 1 PROPOSED IMPACTS TO JURISDICTIONAL AREAS - ACOE/CDFG1 JURISDICTION - RESOURCE IMPACTS (acres) Greens 2 | Oaks/Ridge 3 Total VLCMP Wetlands Freshwater marsh Southern willow scrub Southern willow scrub - disturbed Mule fat scrub Tamarisk scrub SUBTOTAL 2.47 2.51/2.62 0.09/0.27 0.12 0.13 5.32/5.61 0.38 — — —- 0.625/0.38 2.85 2.51/2.62 0.09/0.27 0.12 0.13 5.7/5.99 Non-wetland Waters of the U.S. Open water Streambed SUBTOTAL TOTAL 0.76 0.27 1.03 6.35/6.64 — 0.59 0.59 0.97 0.76 0.82 1.58 7.32/7.61 Impacts for ACOE and CDFG are the same unless separated into two numbers above. When separated, the first number is ACOE jurisdiction and the second number is GDFG jurisdiction. Development footprint for the Greens is based on the plan titled Habitat Conservation Plan Exhibit Villages of La Costa Greens, dated September 1,1998 by T & B Planning Consultants, Inc. Development footprint for the Oaks and Ridge is based on the plan titled Habitat Conservation Plan Exhibit, Villages of La Costa, La Costa Oaks and Ridge, dated September 17, 1998 by Hunsaker and Associates San Diego, Inc. E. FUNCTION AND VALUE OF JURISDICTIONAL AREAS TO BE IMPACTED Jurisdictional areas to be impacted by the proposed project are categorized as ACOE jurisdictional wetlands and non-wetland Waters of the U.S. The impacted wetland habitat types are classified as freshwater marsh (2.85 acres), southern willow scrub (including disturbed) (2.60 acres), mule fat scrub (0.12 acre), and tamarisk scrub (0.13 acre). All of these habitats are also considered sensitive by the California Department of Fish and Game (CDFG) (Holland 1986). Wetland habitat is naturally limited and remaining acreage provides important island habitats for migrant birds. Other important functions of wetlands include flood conveyance; flood storage; sediment control; providing surface water and insects for fish, amphibians and birds; spawning grounds for aquatic fauna; habitat for rare and endangered species; corridors for wildlife movement; and control of water quality and erosion. Of the wetland areas present within the project area, San Marcos Creek is the least disturbed and has the highest current biological value. The creek corridor contains southern willow scrub habitat. The majority of this creek will be preserved with the open space lands on the Oaks/Ridge portion of the project site. Impacted wetlands on the Greens project site have largely been previously disturbed by surrounding land uses and are of low to moderate quality. In addition to these native habitats, one non-native wetland community, tamarisk scrub, occurs on the Greens property. This habitat is dominated by the highly HELIX Conceptual Mitigation Plan far Villages of La Costa/MDI-06/August 9, 2001 3 I III. GOALS OF MITIGATION A. TYPE(S) OF HABITAT TO BE PRESERVED, ENHANCED OR CREATED invasive species tamarisk (Tamarix sp.), which should be eradicated from wetland areas because of its | ability to take over drainages and because it is thought to have low habitat functions for wildlife. The non-wetland Waters of the U.S. within impacted ponds and drainages (including their tributaries) on site JM support little riparian and/or wetland vegetation. These drainages serve largely to conduct runoff during • rainfall events. Freshwater marsh impacted on the Oaks/Ridge site occurs as a strip of vegetation along the margins of • some of the on-site drainages. This habitat is of moderate quality because of its relatively small size. • I I The goal of this mitigation plan is to preserve the functions and values of wetland areas within the VLCMP with the preservation and enhancement of existing riparian habitat combined with the creation of _ additional riparian habitat. The following measures describe mitigation for impacts to 5.7 acres of I wetlands and 1.62 acres of non-wetland Waters of the U.S. The combined wetland creation and enhancement component will mitigate wetland impacts at a 2:1 ratio. Preservation B • The Greens portion would preserve open space that contains most of the primary drainage on site • and associated wetlands (Figure 3a and 3b). | • The Oaks/Ridge open space preserves most of San Marcos Creek, the primary drainage and • associated wetlands on site (Figure 4). This area is especially important because it is high quality • riparian habitat and its importance as a wildlife corridor. A total of 37.88 acres of wetlands will be preserved on the Greens and Oaks/Ridge projects. _ Enhancement • Enhancement of 7.32 acres (1:1 ratio) of existing degraded wetland along the primary drainage on the I Greens project by the removal of pampas grass, giant reed, palms, and other exotic species. • Creation • • Creation of 5.3 acres of willow riparian scrub and willow riparian woodland adjacent to existing wetland habitats along the primary drainage on the Greens project; and _ • Creation of 2.02 acres of southern willow scrub in the south-central portion of the Oaks/Ridge project to offset impacts to 1.62 acres of non-wetland Waters and the remaining 0.3 acres of wetland impacts (1:1 creation ratio). • B. TIME LAPSE It is anticipated that initiation of habitat creation and enhancement will begin concurrent with impacts | associated with the first phase of development for both the Greens and Oaks/Ridge projects (anticipated to be in 2002). A significant portion of the wetland impacts will occur well after the initiation of • HELIX Conceptual Mitigation Plan for Villages of La Costa/M.DI-06/August 9, 2001 I I t-1 8$ £ 3 0) g C/3 (D o o S3 CO CD t =r Enhancement Area QF THEJJ.S. (TYPICA URBAN OUTFAL DRAINAGE COURSE ( .4- AC. LEGEND FRESHWATER SOUTHERN Greens Riparian Enhancement Area LA COSTA GREENS AND OAKS/RIDGE PROPERTIES Figure 3b Job No: MDI-06 Date: 8/8/01 HELIX Oaks Riparian Restoration Site LA COSTA GREENS AND OAKS/RIDGE PROPERTIES Figure 4 I I I I I I I I I I I I I I I I I I I restoration on the Greens project. The wetland mitigation and monitoring program for the VLCMP will take place over a five-year period. The success criteria described below for this project must be met by the end of this period. C. ESTIMATED COSTS The cost of the mitigation described in this document is expected to be approximately $365,000. This amount includes site preparation, installation, maintenance, and monitoring (including maintenance monitoring reports and annual technical reports) for the five-year period. IV. FINAL SUCCESS CRITERIA The following sections provide standards to determine the successful completion of the habitat creation. Attainment of these standards indicates that the mitigation area is progressing toward the target functions and values specified for this plan. The methods to be used to measure these success criteria are described in section VIIIA of this document. A. TARGET FUNCTIONS AND VALUES The goal of the mitigation plan is to create viable riparian habitat of similar or higher quality to the adjacent existing riparian habitat, thereby increasing the habitat functions and values of the restored drainages. B. TARGET HYDROLOGICAL REGIME Water table depth throughout both mitigation areas should be investigated prior to development of grading plans to determine what elevation the ground surface level should be for each created community. Southern willow scrub should be between two and four feet above the water table (Baird and Rieger 1988). The long-term source of water will be from natural runoff and from the drainage on site, although irrigation will be used to aid container stock establishment and growth. Based on the location and width of adjacent habitat and the successful implementation of the Bressi Ranch restoration project immediately upstream, it is anticipated that the hydrological regime will be easily met. C. TARGET JURISDICTIONAL ACREAGE TO BE CREATED Based on the target hydrological regime for the site, willow riparian scrub (consisting of southern willow scrub) and willow riparian woodland will be created as part of the proposed project's mitigation requirements. These scrub and woodland habitats should meet the criteria for jurisdictional wetlands as defined in the ACOE delineation manual (1987). Willow riparian scrub occurs within stream courses and includes several habitat categories including: mule fat scrub, tamarisk scrub, floodplain scrub, and southern willow scrub. This mitigation plan proposes to create southern willow scrub habitat. Southern willow scrub consists of dense, broadleaved, winter-deciduous stands of trees dominated by shrubby willows (Salix sp.) in association with mule fat (Baccharis salidfolia). This habitat typically occurs on loose, sandy or fine gravelly alluvium deposited near stream channels during flood flows. Frequent flooding maintains this early serai community, preventing succession to a riparian woodland or forest (Holland 1986). HELIX Conceptual Mitigation Plan for Villages of La Costa/MDI-06/August 9, 2001 V. PROPOSED MITIGATION SITE A. LOCATION AND SIZE OF MITIGATION AREA C. EXISTING FUNCTIONS AND VALUES OF MITIGATION AREA Conceptual Mitigation Plan for Villages of La Costa/MDI-06/August 9, 2001 I Willow riparian woodland is an open to dense riparian community that is dominated by willow species J (Salix sp.). This community occurs along large stream courses where there is an abundant supply of water at or near the surface for most of the year. The absence of large, frequent disturbances, usually in _ the form of floods, allows the component tree species to attain a sizable height and overall taller canopy • structure. I I Two on-site mitigation areas, one for each of the subject properties, are proposed as part of this plan. On the Greens site, 5.3 acres of riparian habitat creation and an additional 7.32acres of enhancement will be m located along the riparian corridor that crosses this parcel from east to south. This mitigation site would I enhance existing riparian habitat and expand the corridor by creating additional wetland habitat. - On the Oaks/Ridge site, a 2.02-acre riparian mitigation site containing southern willow scrub will be located in the southern end of the Oaks parcel. This mitigation site will create wetland habitat in an area that is • currently undeveloped, but that will be disturbed by construction. This area will be installed after site • grading is completed. The total combined mitigation area is 7.32 acres of creation and 7.32 acres of enhancement. I B. OWNERSHIP STATUS Real Estate Collateral Management currently owns the entire project area, including the mitigation area, | in fee title. Long-term ownership of the mitigation site on the Greens parcel will reside with the Center for Natural Lands Management in their capacity as manager of the entire La Costa Preserve HCP area. _ Long-term ownership of the mitigation site on the Oaks/Ridge parcels will reside with the homeowners • association for that project. I The riparian corridor on the Greens property that is proposed for habitat enhancement and restoration currently contains freshwater marsh, southern willow scrub, and disturbed habitat. Due to the abundance • of non-native species in this portion of the corridor, the overall quality of existing habitat in this area is | moderate. Non-native species present in the freshwater portion of the enhancement area include tamarisk (Tamarix sp.), curly dock (Rumex crispus), bristly ox-tongue (Picris echiloides), rabbitfoot _ beardgrass (Polypogon monspeliensis), and cocklebur (Xanthium strumarium). Existing southern willow • scrub habitat in the enhancement area contains native willows (Salix sp.), mule fat (Baccharis salicifolia), southwestern spiny-rush (Juncus acutus), mugwort (Artemisia douglasiana), and yerba mansa (Anemopsis californica); however, it also contains a number of non-native invasive species including tamarisk, fennel • (Foeniculum vulgare), pampas grass (Cortaderia sp.), and eucalyptus (Eucalyptus sp.). The remainder of the • mitigation area is disturbed and is dominated by non-native moisture-loving species such as pampas grass, fennel, bristly ox-tongue, and wild lettuce (Lactuca serriola). Though disturbed, this riparian • corridor likely serves numerous functions for wildlife in its current state. These functions include | providing permanent habitat for wetland-dependent species and supplying cover, water, and a corridor for movement for other wildlife species. These functions will be enhanced with the mitigation measures • proposed in this plan. I The mitigation area located on the Oaks parcel of the Oaks/Ridge project area occurs in an area that is currently upland habitat consisting of native grassland and Diegan coastal sage scrub. Both of these • HELIX I I I I I I I I I I I I I I I I I I I I I upland habitat types are considered sensitive by the City of Carlsbad and the CDFG and have high habitat value. A portion of the coastal sage scrub habitat located within the mitigation area has been identified as being occupied by coastal California gnatcatchers (Polioptila californica californica) (Hunsaker and Associates April 2000). While the mitigation area currently supports these habitats, they will be lost from grading impacts for the project that are unrelated to any restoration. D. PRESENT AND PROPOSED USES OF MITIGATION AREA Mitigation sites on both project sites are currently undeveloped, and with the exception of the breached earthen dam on the Greens project, contain no man-made structures. Much of the proposed restoration area on the Greens has been degraded by surrounding land uses. The Oaks/Ridge project area is currently relatively undisturbed with the exception of the borrow area in the central portion of the Oaks project. It is proposed that both mitigation areas will remain undeveloped and managed as permanent open space. E. JURISDICTIONAL DELINEATION (If applicable) Not applicable. F. PRESENT AND PROPOSED USES OF ALL ADJACENT AREAS On the Greens project site, the riparian corridor mitigation area is bordered by an existing golf course to the west and planned residential development to the north and south. The western portion of the mitigation site will connect with Open Space that extends south approximately one quarter of a mile to Alga Road. The eastern portion of the mitigation area will connect with a large block of designated Open Space to the east. In addition, two roads wiD be constructed through the mitigation area; Poinsettia Lane, an east-west road, will parallel the mitigation area to the north, and Alicante Road, oriented north south, will bisect the western portion of the mitigation site. On the Oaks project site, the mitigation site will be surrounded by residential development to the south, east and west. The southern edge of the mitigation area connects with approximately four acres of existing oak woodland habitat immediately offsite. Beyond this additional open space, the site is again surrounded by residential development. The easternmost portion of the mitigation site does not connect to but extends for approximately 120 feet from a large area of open space to the northeast. VI. IMPLEMENTATION PLAN A. RATIONALE FOR EXPECTING IMPLEMENTATION SUCCESS The site selected for riparian habitat creation is in an area that, either already supports, or with topographic modification should have the appropriate hydrology and soils to support this habitat. On the Greens property, riparian habitat occurs immediately adjacent to the restoration area, and, due to the presence of moisture-loving disturbed species, is likely to have existed previously in at least in portions of the area proposed for wetland creation. The area slated for restoration on the Oaks/Ridge property is expected to succeed due to increased water availability after grading. This change in hydrology is anticipated to create conditions conducive to the growth of riparian vegetation. The scope of this mitigation plan is similar to other successful riparian mitigation projects. HELIX Conceptual Mitigation Plan for Villages of La Costa/MDI-06/August 9, 2001 B. RESPONSIBLE PARTIES 1. Project Proponent HELIX Conceptual Mitigation Plan for Villages of la Costa/MD1-06/August 9, 2001 I I IThe project proponent and owner (Real Estate Collateral Management Company) will be responsible for financing pre-grading plan hydrological testing, installation, maintenance, and monitoring of the habitat creation. In order to ensure the success of mitigation, the project proponent will enter into a five-year, I secured agreement with the ACOE to cover the projected cost to install, monitor, and report on the | mitigation. This agreement should be in the form of a 120 percent bond. The bond should be structured so that portions of the bond may be released as interim milestones are met (subject to negotiation between • the proponent and the ACOE, in concurrence with the CDFG) (see section VIII A of this report). | 2. Landscape Architect _ A licensed landscape architect shall prepare the construction drawings to accompany this mitigation plan. * The construction drawings shall be reviewed and approved by the restoration specialist. 3. Restoration Specialist • Site preparation and installation monitoring as well as maintenance/technical monitoring of the • mitigation area shall be the responsibility of a biologist, landscape architect, horticulturist, or other person | knowledgeable in native habitat creation/restoration. After each visit, the restoration specialist shall provide the project proponent and installation/maintenance contractor with a written checklist of _ maintenance items in need of attention, if any. All requests for work that are in addition to a contractor's I scope of work shall first be approved by the project proponent. The restoration specialist shall educate the installation and maintenance contractors with regard to mitigation goals and requirements. 4. Installation Contractor • The installation contractor must be educated as to the installation and maintenance of native plants. The • installation contractor shall be responsible for completion of grading, pre-planting weed control, | irrigation system installation, planting, seeding, and final as-built plans. Once the restoration specialist has verified the completion of the previous list of items, a 120-day installation maintenance period will • begin. The installation contractor shall be required to maintain the entire mitigation area at least once a • month. The installation contractor shall meet the restoration specialist at the site, when requested, and shall perform all maintenance items in need of attention in a timely manner. Maintenance tasks include, but are not limited to, dead plant replacement, reseeding, irrigation system repair, and weed control. At I the end of the installation maintenance period, the restoration specialist will certify completion of the • installation contract provided all installation and maintenance tasks have been completed. The project proponent may change contractors at its discretion. • 5. Maintenance Contractor After the installation contract is certified as complete, the project proponent will hire a maintenance • contractor for the duration of the five-year monitoring period. The maintenance contractor must be educated as to the maintenance of native plants. The maintenance contractor shall maintain the entire _ mitigation area according to a specified schedule (see Section VIID of this document). Maintenance tasks • include, but are not limited to, dead plant replacement, reseeding, irrigation system repair, and weed ™ I I I I I I I I I I I I I I I I I I I I I I control. The maintenance contractor shall meet the restoration specialist at the site, when requested, and shall perform all maintenance items in need of attention in a timely manner. The project proponent may change contractors at its discretion. C. SCHEDULE It is anticipated that habitat creation/enhancement on the Greens project site will be initiated no later than commencement of project impacts. Work on the Oaks/Ridge wetland restoration area will not begin until after project grading has been completed since the wetland hydrology in this area is largely dependent on the post-grading topography. Initial activities will include installing protective fencing, grading, and installing the irrigation system. Planting and seeding will follow, preferably between November 15 and March 15 to take advantage of winter rains (see section VI E 10 of this document). Monitoring will begin at the grading/site preparation phase and will continue through the end of the five-year monitoring period. D. SITE PREPARATION Existing riparian habitat shall be protected during the grading/site preparation and installation phases by the use of (orange) plastic construction fencing. The restoration specialist shall flag the limits of the mitigation work area to identify where the fencing should be installed and shall inspect the fencing prior to grading. The restoration specialist shall certify in writing to the ACOE and CDFG that the limits of the mitigation work area have been properly fenced before the installation contractor may proceed with work. The fencing shall remain in place until the end of the grading/site preparation and installation phases or until the restoration specialist considers it no longer necessary. Any damage to protective fencing shall be repaired within one week of damage by the contractor responsible for site maintenance at the time of damage. If mitigation activities occur outside the construction fencing, the restoration specialist may recommend installation of a temporary six-foot chain link fence in place of the plastic construction fencing. Any damage to existing riparian vegetation (or other area outside the construction fencing) caused by a contractor shall be repaired by the contractor at its expense. The contractor shall bear the full cost of having a mitigation plan and accompanying construction drawings prepared for the damaged area as well as the cost for maintenance and technical monitoring according to the same standards as this mitigation plan. Grading that will remove accumulated alluvium and bring the ground surface closer to the water table will be necessary (see section IV B of this document). Care must be taken to reduce sedimentation of the existing riparian community and drainage through installation of silt fencing along the graded edge. The silt fencing shall remain in place until the end of the grading/site preparation and installation phases or until the restoration specialist considers it no longer necessary. Any damage to the fencing shall be repaired within one week of damage by the contractor responsible for site maintenance at the time of damage. The mitigation site must be made weed free by the installation contractor prior to planting. This can be accomplished by hand weeding or by a grow and kill methodology. The restoration specialist will make the final determination as to the appropriate methodology at the time of project implementation. HELIX Conceptual Mitigation Plan for Villages of La Costa / MDI-06 / August 9, 2001 E. PLANTING PLAN 1. Willow Riparian Scrub (including Southern Willow Scrub) A mosaic of willows (Salix spp.) and cottonwood (Populus fremontif) shall be created to attain a mature overstory canopy. The southern willow scrub would support an understory of mule fat (Baccharis salicifolia}, goldenbush (Isocoma menziesii), and California blackberry (Rubus ursinus). Liner and/or one-gallon nursery grown container plants, grown from cuttings propagated from on site or nearby sources, and local, native seed shall be used in creating this habitat. Seeding will include annual and perennial species. Fast growing annual species that are quick to germinate will provide initial cover and protect freshly graded soils from erosion. During the course of plant succession it is anticipated that perennial species will eventually be dominant. The plant species, size, density, and quantity for planting is presented in Table 2. Scientific Name CONTAINER STOCK Overstory Populus fremontii Salix gooddingii Salix lasiolepis Salix exigua Understory Baccharis salicifolia Isocoma menziesii Iva haysiana SEED MIXTURE Ambrosia psilostachya Artemisia douglasiana Juncus acutus ssp. leopoldii Anemopsis califomica Table 2 SOUTHERN WILLOW SCRUB PLANT PALETTE Spacing on Container Common Name Center Size Fremont cottonwood black willow arroyo willow sandbar willow mule fat goldenbush San Diego marsh-elder western ragweed Douglas sagewort southwestern spiny rush yerba mansa TOTAL 15ft. 12ft. 10ft. 6ft. 6ft. 4ft. 4ft. Lbs/Acre 6 3 2 _4 15 liner /I gal. liner/ 1 gal. liner/ 1 gal. liner /I gal. TOTAL liner/1 gal. liner/ 1 gal. liner/ 1 gal. TOTAL No. per acre 25 115 190 100 430 460 450 240 1,150 HELIX Conceptual Mitigation Plan for Villages of La Costa/MDI-06/August 9, 2001 10 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 2. Willow Riparian Woodland This habitat is restored using a similar plant palette as for willow riparian scrub with the addition of several later successional and upland species (Table 3). Over time, an absence of flooding, particularly along the margins of the stream course, will permit this later serai community to develop. It will likely take greater than the five-year monitoring period for this community to fully evolve. Table 3 RIPARIAN WOODLAND PLANT PALETTE Scientific Name Container Stock Overstory Platamis racemosa Sambucus mexicana Quercus agrifolia. Populus fremontii Salix lasiolepis Understory Baccharis salicifolia Isocoma menziesii Rubus iirsinus Iva haysiana Seed Mixture Ambrosia psilostachya Anemopsis califomica Artemisia douglasiana Bromus carinatus Juncus acutus ssp. leopoldii Muhlenbergia rigens Nassella lepida Spacing on Common Name Center western sycamore 15 ft. blue elderberry 12 ft. coast live oak 15 ft. Fremont cottonwood 15 ft. arroyo willow 10 ft. mule fat 6 ft. goldenbush 4 ft. California blackberry 4 ft. San Diego marsh-elder 4 ft. Lbs/Acre western ragweed 6 yerba mansa 4 Douglas sagewort 3 California brome 3 southwestern spiny rush 2 California deergrass 3 foothill needlegrass _3 TOTAL 24 Container Size liner/1, gal. liner/1 gal. liner/ 1 gal. liner/ 1 gal. liner/ 1 gal. TOTAL liner/ 1 gal. liner /I gal. liner /I gal. liner/ 1 gal. TOTAL No. per acre 50 60 40 25 170 345 310 345 175 175 1,005 HELIX Conceptual Mitigation Plan for Villages of La Costa/MDI-06/August 9, 2001 I 3. Contract Growing and Plant Material Sources | Arrangements shall be made as soon as possible in advance of the expected planting date, either by the — project proponent or the installation contractor, to acquire container plant materials and seed required for • habitat creation. An additional 10 percent of the total number of container plants shall be grown to replace those that die. [[[Is this really necessary? Does this really happen in practice?]]] An additional 10 percent of the seed mix shall be procured in case reseeding is necessary. A copy of the plant material • contract shall be submitted to the restoration specialist as verification of acquisition. Contract growing • and seed collection shall be conducted by an experienced native plant nursery or seed company such as, but not limited to, Tree of Life Nursery, San Juan Capistrano, California; Mockingbird Nursery, Riverside, • California; and/or S&S Seeds, Carpiriteria, California. | It is preferred that the source of all plant material used at the site be from the drainage on site or as close • to the site as possible. If necessary, the restoration specialist shall help the grower locate acceptable local • sources for plant materials. 4. Substitutions I No species shall be substituted without approval from the restoration specialist. If the project proponent or installation contractor is unable to obtain the proper species (and sizes) specified by the time of • planting, commencement of the 120-day installation maintenance period shall be delayed until all plants • specified are in the ground. Substitution of plant material at the time of planting depends solely upon the discretion of the restoration specialist in consultation with the landscape architect. The installation • contractor in the final set of as-built plans shall document any substitutions that are approved. J 5. Plant Material Inspection _ All plant materials shall be inspected by the restoration specialist and approved as healthy, disease free, * and of proper size prior to planting. Overgrown, root-bound container stock will be rejected. In addition, the restoration specialist shall approve the final layout of all plant materials in the field prior to planting I to ensure their correct ecological positioning (e.g., plants are not installed in rows). • 6. Container Plant Guarantees • The installation contractor shall replace all plants determined to be dead or terminally diseased as soon as possible but no more than 90 days after installation. - Plant replacement by the maintenance contractor _ shall be completed as soon as possible but no more than 90 days following written direction from the I restoration specialist. Unless the restoration specialist approves substitutions, the replacement plants shall be of the same species and at least the same size as originally planted. All replacement plants shall be inspected by the restoration specialist and approved as healthy, disease free, and of proper size prior • to planting. • 7. Seed Guarantees • The installation contractor shall guarantee a 50 percent germination coverage rate for all seeded areas (based on visual assessment by the restoration specialist) at the end of the 120-day installation • maintenance period. If there are particular bare areas, reseeding shall take place in those areas at the • direction of the restoration specialist. The restoration specialist shall determine the timing and method for reseeding. I HELIX Conceptual Mitigation Plan far Villages of La Costa / MDl-06 / August 9, 2001 12 I I I I I I I I I I I I I I I I I I I I I 8. Planting Methods All container stock shall be planted in a hole at least twice the diameter of the container and twice the depth. Backfill shall not be amended. The top of the root ball shall be set one inch above finish grade. A mulched zone shall then be established around each container plant, extending for at least 18 inches from the base of the plant. The mulch shall be two to four inches thick and must not come in contact with the collar of the plant. The seed mix shall be hydroseeded. Fertilizer shall not be applied, except in extraordinary circumstances, and only at the written direction of the restoration specialist. 9. Timing for Installation of Plant Material Planting and then seeding shall occur between November 15 and March 15 to take advantage of winter rains. Since irrigation will be provided for the container stock, planting (but not seeding) could occur into spring, but extreme care would need to be taken not to trample the previously spread seed mix. F. IRRIGATION PLAN A drip or bubbler-type irrigation system shall be installed for the willow riparian scrub and woodland habitats prior to planting and seeding. Water shall be applied only as needed to prevent the mortality of seedlings. The irrigation schedule shall incorporate evenly spaced, infrequent, deep applications of water. To obtain deep penetration of water, the irrigation system may be activated several times in one 24-hour period. The irrigation system will incorporate the use of moisture sensors connected to an irrigation controller. This will allow for the application of water on an as-needed basis. Irrigation is only expected to be used for the first three years, or less, of the five-year monitoring period. During the final two years, the restoration specialist shall determine whether or not irrigation is still necessary. Once the restoration specialist has determined that irrigation is no longer necessary, the "above-ground" portions of the system shall be removed under the direction and supervision of the restoration specialist. G. AS-BUILT CONDITIONS The installation contractor shall prepare, and the restoration specialist shall submit, as-built plans of the mitigation area to the ACOE and CDFG within six weeks of completing site preparation and planting. The plans, prepared by the installation contractor, will include an as-built topographic map as well as areas of grading, planting, and seeding. HELIX Conceptual Mitigation Plan for Villages of La Costa/MDl-06/August 9, 2001 13 VII. MAINTENANCE DURING MONITORING PERIOD A. MAINTENANCE ACTIVITIES 1. General Maintenance All contractors shall be informed of the mitigation goals and maintenance requirements. Only construction equipment necessary to accomplish the mitigation installation shall be allowed on the mitigation site, and each piece of construction equipment shall be removed from the site as soon as its task is complete. No vehicular fluids shall be added or changed on site. Once plant installation and seeding has begun, no vehicles shall be allowed on the mitigation site. Workers' personal vehicles shall be parked outside the mitigation area. The mitigation site shall be kept free of human garbage. No power tools shall be operated on the mitigation site from March 15 through July 15. Only activities that can be performed with non-power tools shall be allowed during this period. This time period coincides with the breeding season of many sensitive riparian bird species. • Damage to plants or the irrigation system on the mitigation site as a result of unusual weather or vandalism shall be repaired as directed by the restoration specialist. The project proponent shall pay for such repairs. The contractor at its expense, as determined by the restoration specialist, shall repair any damage caused by a contractor's inadequate maintenance. A five-year maintenance program is provided to ensure the successful establishment of created and enhanced habitats. Maintenance monitoring by the restoration specialist will begin immediately after completion of the 120 day installation period for habitat creation and initial exotics removal for habitat enhancement, and continue through year five (Table 4). The maintenance of habitats will involve debris (trash) removal, exotic species removal, and any remedial measures deemed necessary by the restoration specialist for the success of the mitigation program. Exotic plant species will be removed by hand whenever possible, although some species may only be effectively controlled through local treatment by cutting and applying an aquatic herbicide (e.g., Rodeo™). Table 4 RESTORATION SPECIALIST MAINTENANCE MONITORING SCHEDULE PHASE Site Preparation/ Installation SCHEDULE Daily Post Installation First four months following installation (120 day installation period) Remainder of first two years December to May June to November Year Three December to May June to November Years Four and Five Two times per month Monthly Every two months Monthly Quarterly Quarterly HELIX Conceptual Mitigation Plan for Villages of La Costa/MDI-06/August 9, 2001 14 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I The restoration specialist will determine the need for weeding and will contact the installation or maintenance contractor for any required work beyond the regular maintenance of the site. Regular maintenance of the site will occur at least once a month. Personnel will be trained to distinguish weed species from desirable, native vegetation. Fertilizer will not be applied and pruning will not be performed. 2. Irrigation The installation and maintenance contractors shall inspect the installed container stock for signs of over- or under-watering during their maintenance periods. Signs of over- or under-watering shall be reported immediately to the restoration specialist so that the irrigation schedule can be adjusted accordingly. 3. Weed Control Weed control shall be conducted monthly by the installation contractor and per the schedule in section VII C of this document for the maintenance contractor, or as necessary, to minimize competition that could prevent the establishment and growth of native species. As weeds become evident, they shall be removed by hand. Maintenance personnel shall be trained to distinguish weed species from desirable native vegetation. A mulched area 18 inches from the base of each container plant shall be maintained to minimize competition from weeds during the establishment period (120 days following certification of the installation contract) or until plants reach 2 to 3 feet in height. Examples of weeds to be controlled include, but are not limited to, castor bean (Ricinus communis), eastern cocklebur (Xanthium strumarium), giant reed (Arundo donax), eucalyptus (Eucalyptus spp.), tamarisk (Tamarix parviflora), pampas grass (Cortaderia jubata), black mustard (Brassica nigra), Bermuda grass (Cynodon dactylon), and hottentot fig (Caropobrotus edulis). 4. Disease and Other Pests Damage causing insects, high levels of herbivory, and diseases shall be monitored by the installation and maintenance contractors during their maintenance periods. Generally speaking, a high threshold of tolerance will be permitted before chemical/lethal control measures are considered. A licensed pest control adviser as required by law will only make all specific recommendations. All applicable federal and state laws and regulations will be closely followed. The restoration specialist will be consulted on any pest control matters. 5. Pruning No pruning shall be done unless directed by the restoration specialist. B. RESPONSIBLE PARTIES Real Estate Collateral Management will be responsible for financing the maintenance program. The restoration specialist will be responsible for overall supervision of the installation, maintenance, and monitoring of the mitigation project. The installation contractor will be responsible for site preparation (excavation), and removal of invasive, exotic plant species, and debris (trash) from the mitigation areas. The installation contractor will also be responsible for plant materials procurement, planting, seeding, weed removal, and maintenance. The maintenance contractor will be responsible for maintenance items HELIX Conceptual Mitigation Plan far Villages of La Costa / MDI-06 / August 9, 2001 15 such as, but not be limited to, weed control, dead plant replacement, re-seeding for the habitat 1 creation • areas, and eradication of invasive (exotic) plant species for the habitat enhancement areas. C. SCHEDULE 1 Mitigation areas will be maintained by the installation and maintenance contractors according to the _ schedule in Table 5. Table 5 MAINTENANCE SCHEDULE PHASE First three months following installation* Remainder of first two years January to April May to December Years three, four, and five January to April May to December SCHEDULE Two times per month Two times per month Monthly Monthly Every two months 1 1 1 *Performed by installation contractor (120-day installation period). Remainder of five years ™ performed by maintenance contractor. 1 VIII. MONITORING PLAN A. PERFORMANCE CRITERIA 1 Performance criteria are specific standards by which to evaluate the progress and success of the B mitigation. The standards are based on the reference site.Three categories of success criteria shall be • analyzed: species diversity, cover by weeds, and cover by native species. The annual milestones for these — parameters are presented in Table 6. Table 6 ANNUAL SUCCESS CRITERIA MILESTONES FOR VILLAGES OF LA COSTA1 Year Criteria 1 2 3 4 5 Species Diversity 40 50 60 70 80 Cover by Weeds2 140 130 120 110 100 Cover by Native Species2 60 70 80 90 100 1 Values are percentages as compared with the reference site 2 Percent total cover HELIX Conceptual Mitigation Plan for Villages of La Costa /MDI-06/ August 9, 2001 1 1 1 I • .. 1 I I I I I I I I I I I I I I I I I I I B. MONITORING METHODS Two randomly located, five-meter by 50-meter belt transects per acre shall be used to measure species diversity. All species that occur within the belt transect shall be noted. The various belt transects shall be permanently marked to facilitate their use in subsequent years. Herb, shrub, and tree vegetation layers shall be sampled by a line transect down the middle of each belt transect to measure percent total cover of native species and weeds. At each 0.5-meter interval, the species that intercept that point shall be recorded according to strata using the California Native Plant Society's Field Sampling Protocol (1996). In addition to the measurements described above, several permanent stations for photo-documentation shall be established in each habitat type and annual photographs taken. All of the above sampling techniques shall be used annually at the reference site as well to measure species diversity, cover by weeds, and cover by native species. The reference site shall be the existing riparian habitat along the drainage on and off site. 1. Species Diversity Species diversity usually increases with recruitment of new native species from the surrounding native habitats. The effect of recruitment on diversity should allow the mitigation to approach the level of species diversity at the reference site. After five years, the mitigation site should reach 80 percent of the species diversity of the reference site. 2. Cover by Weeds Many weeds have become naturalized, and therefore, the weed cover should reflect (or be less than) what is present at the reference site. Although weeds are expected, they should not be allowed to get out of control on site. Weeds should be controlled during site maintenance. 3. Cover by Native Species Cover by native vegetation should increase over time and ultimately approach that of the reference site. With sufficient site maintenance, proper irrigation, and natural rainfall, native vegetation cover should approach 100 percent of the reference site in five years. C. ANNUAL REPORTS Annual reports shall include botanical observations and notes on wildlife use of the mitigation area and reference site. Remedial recommendations, if necessary, shall be made in the annual reports as well as a summary of whether or not the mitigation is meeting the success criteria for the appropriate year. D. SCHEDULE The first annual monitoring of the Greens wetland mitigation project is expected to occur in June of the first growing season after installation of the restoration area. Annual monitoring of the Oaks/Ridge restoration project will also begin one growing season from installation. Annual technical HELIX Conceptual Mitigation Plan for Villages of La Costa/MDI-06/August 9, 2001 17 I monitoring reports shall be submitted to the ACOE and CDFG by the end of September of each year to J ensure that there is adequate time remaining in the dry season to implement any necessary contingency measures. m IX. COMPLETION OF MITIGATION A. NOTIFICATION OF COMPLETION • The project proponent shall notify the ACOE and CDFG upon completion of the mitigation effort through • the submittal of the final annual technical monitoring report. The final report shall include a | jurisdictional delineation of the mitigation areas. This delineation must show that the goals of the mitigation (as described in section III of this document) have been met. • B. AGENCY CONFIRMATION After receipt of the final annual technical monitoring report, the ACOE and CDFG may inspect the • mitigation site to determine the accuracy of the jurisdictional delineation. ™ X. CONTINGENCY MEASURES A. INITIATING PROCEDURES HELIX Conceptual Mitigation Plan far Villages of La Costa/MDI-06/August 9, 2001 18 I I If the ACOE and CDFG determine upon receipt of any of the annual monitoring reports that the mitigation effort is not meeting success standards for the project, the ACOE shall notify the project « proponent in writing that the mitigation effort may require augmentation for successful implementation. • The project proponent shall have 30 days to respond to the ACOE correspondence, confirming their agreement that contingency measures will be required. B. ALTERNATIVE LOCATIONS FOR CONTINGENCY MITIGATION I No alternative locations are proposed for this mitigation. If the success criteria are not being met on site, • the ACOE and the project proponent will work towards a mutual solution. | C. FUNDING MECHANISM _ The project proponent shall be responsible for all costs associated with any contingency measures. D. RESPONSIBLE PARTIES • The project proponent shall be the responsible for any necessary contingency measures (see Section II C of this document).I I I I I 1 1 1 •1 1 XL LITERATURE CITED Baird, Kathryn J. and J. P. Rieger. 1988. A Restoration Design For Least Bell's Vireo Habitat County. Presented at the California Riparian Systems Conference; September 22-24, California. USDA Forest Service Gen. Tech. Rep. PSW-110. 1989. California Native Plant Society. 1996. Field Sampling Protocol. Located on California Native Home Page. Carlsbad, City of. 1999. Habitat Management Plan for Natural Communities in the City April. In San Diego 1988; Davis, Plant Society of Carlsbad. City of Carlsbad and Fieldstone/La Costa Associates. 1995. Habitat Conservation Plan for Plant and Wildlife Species of Concern on Properties in the Southeast Quadrant of the City California. Review Draft. Helix Environmental Planning, Inc. 1999. Bressi Ranch Draft Conceptual Mitigation Plan. of Carlsbad, Holland, R.F. 1986. Preliminary descriptions of the terrestrial natural communities of California. State of 1 1 1 1 1 1 1 1 1 1 California, The Resources Agency, 156 pp. U.S. Army Corps of Engineers. 1987. Corps of Engineers Wetlands Delineation Manual. Waterways Experiment Station, Vicksburg, Mississippi. U.S. Army Corps of Engineers. 1993. Habitat Mitigation and Monitoring Proposal Guidelines. Regulatory Branch. June 1. • HELIX Conceptual Mitigation Plan far Villages of La Costa / MDI-Q6 /August 9, 2001 U.S. ACOE Los Angeles, 19