San Diego River Tributary Canyons Project
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San Diego River Tributary Canyons Project PROJECT FEASIBILITY REPORT FINAL REPORT APRIL 27, 2010 PREPARED FOR San Diego River Conservancy and California Coastal Conservancy San Diego River Tributary Canyons Project FINAL REPORT PREPARED FOR San Diego River Conservancy and California Coastal Conservancy April 27 2010 CONSULTANT TEAM Dick Rol Craig Richardson acknowledgements The Foothill Associates team would like to thank the following organizations and individuals whose vision, guidance, and support made this report possible. SAN DIEGO CITY COUNCIL NORMAL HEIGHTS COMMUNITY Council Member Donna Frye - District 6 PLANNING GROUP Council Member Todd Gloria - District 3 Jim Baross - Chair SAN DIEGO RIVER CONSERVANCY MISSION VALLEY COMMUNITY Mayor Jerry Sanders PLANNING GROUP Council Member Donna Frye - Board Chair Linda Kaufman - Chair Toni Atkins County Supervisor Dianne Jacob SERRA MESA COMMUNITY thomas L. Sheehy PLANNING GROUP Karen Scarborough Doug Wescott - Chair Ruth Coleman Ann Miller Haddad FRIENDS OF NORMAL HEIGHTS CANYONS Benjamin Clay Kevin Johnston Andrew Poat Greg Konar Ruth Hayward Mark St. John John Donnelly David King FRIENDS OF RUFFIN CANYON Mike Nelson - Executive Officer Bonnie Hough Monica Fuentes CALIFORNIA COASTAL CONSERVANCY Jim King SAN DIEGO CANYONLANDS Mary Small Eric Bowlby Jon Gurish SAN DIEGO GAS & ELECTRIC SAN DIEGO RIVER PARK FOUNDATION Jeff Sykes Rob Hutsel DAVID EVANS AND ASSOCIATES CITY OF SAN DIEGO Gernot Komar PARK AND RECREATION DEPARTMENT Edward Blake Rick Thompson Laura Ball UCSD JACOBS SCHOOL OF ENGINEERING Jason Allen Frieder Seible CITY OF SAN DIEGO LAND CONSERVATION BROKERAGE, INC. PLANNING DEPARTMENT Ann Van Leer Brian Schoenfisch Robin Shifflet table of contents Executive Summary E-1 Section 1: Introduction & Background 1.1 San Diego River Corridor Vision 1-1 1.2 Tributary Canyons Vision 1-2 1.3 Goals and Objectives 1-4 1.4 Project Benefits 1-6 1.5 Planning Context 1-8 1.6 Planning Process 1-12 Section 2: Existing Conditions 2.1 Existing Trails and Uses 2-2 2.2 Ownership, Easements, and Utilities 2-16 2.3 Community Context 2-19 2.4 Biological Resources 2-20 2.5 Archaeological/Cultural Resources 2-32 2.6 Water Resources 2-32 2.7 Geology and Soils 2-34 2.8 Hazardous Materials 2-38 2.9 Slopes 2-39 2.10 Scenic Resources 2-39 2.11 Crime 2-44 Section 3: Concept Plan - Recommendations 3.1 Recommended Trail Route - Overview 3-1 3.2 Planning Process 3-2 3.3 Segment A: Normal Heights Canyon Trail 3-3 3.4 Segment B: Serra Mesa Canyon Trail 3-18 3.5 Segment C: Mission Valley Urban Trail 3-32 3.6 Design Guidelines / Standards 3-50 3.7 Interpretive Program 3-55 Section 4: Trails Implementation Summary 4.1 Part 1 - Canyon Trails 4-2 4.2 Part 2 - Mission Valley Urban Trail 4-14 4.3 Part 3 - San Diego River Crossing 4-18 Appendix A: Alternative 2 and 3 Trail Descriptions Appendix B: Real Estate Tables Figures 2.1 Project Segments 2-3 2.2 Ellison Canyon Existing Trails 2-5 2.3 Ruffin/Sandrock Canyon Existing Trails 2-11 2.4 Mission Valley Existing Trails 2-13 2.5 Ellison Canyon Natural Resources 2-23 2.6 Ruffin/Sandrock Canyon Natural Resources 2-25 2.7 Mission Valley Natural Resources 2-27 2.8 Geology, Soils, and Hazardous Materials 2-35 2.9 Slopes and Scenic Resources 2-41 2.10 Crime 2-45 3.1 Ellison Canyon Route Alternatives 3-11 3.2 Serra Mesa Route Alternatives 3-19 3.3 Mission Valley Concept Plan 3-35 Tables 2.1 Existing Ownership Acreages 2-16 2.2 Existing Easement Interests 2-17 2.3 Soils 2-37 2.4 Hazardous Materials 2-38 3.1 Normal Heights Alternative Route Evaluation 3-5 3.2 Normal Heights Canyon Scoring Matrix Summary 3-6 4.1 Biological Impacts: Part 1 - Canyon Trails 4-3 4.2 Ellison Canyon Real Estate Needs 4-9 4.3 Sandrock Canyon Real Estate Needs 4-11 4.4 Preliminary Cost Estimate: Part 1 - Canyon Trails 4-13 4.5 Biological Impacts: Part 2 - Mission Valley Urban Trail 4-15 4.6 Preliminary Cost Estimate: Part 2 - Canyon Trails 4-17 executive summary E he San Diego River Tributary Canyons Project proposes a trail connection from Normal Heights, Tacross Mission Valley, and into Serra Mesa. The trail would create critical pedestrian and bicycle connections between the three communities; connections that have long been desired by each com- munity and which have been recommended by a number of community scale and City-wide planning Summary Executive documents. The proposed trail would provide direct non-vehicular access from the adjacent commu- nities to the major recreational backbone being created along the San Diego River corridor. It would also provide an important opportunity for residents in each neighborhood to experience and learn about the natural areas that define much of San Diego’s character. Finally, it would make critical new connections that open up access for thousands of residents and commuters to the MTS Trolley system and the shopping opportunities in Fenton Marketplace. The trail would advance progress toward the vision for the San Diego River Park as well as progress toward regional goals of sustainability, healthy lifestyles, environmental awareness, and overall quality of life in San Diego. The proposed route begins in Normal Heights at the intersection of North Mountain View Drive and 33rd Street. It proceeds for a total length of 7,476 feet as it passes through Ellison Canyon, across I-8 using the Mission City Parkway bridge, across the San Diego River via a proposed non-vehicular bridge, through Fenton Marketplace and the Escala Development via the existing Mission City Trail, Introduction & background and to the end of Sandrock Road via Sandrock Canyon. Approximately 2,909 feet of the route follows existing trails or SDG&E canyon access roads that would require little to no improvement. Approximately 4,567 feet of new trail is proposed to ensure a sustainable trail route or to fill gaps in the route. Additional features proposed include a new non-vehicular bridge over the San Diego River, a plaza or park space adjacent to the river, modest trailhead facilities, habitat restoration within the canyons and along the river, and interpretive elements. The proposed trail alignment was chosen after an exhaustive search of possible trail routes and the evaluation of alternative alignments within the selected overall route corridor. The proposed alignment is preferred primarily because it ) provides the most direct possible connection between key destinations along the trail, 2) provides the desired quality and character of experience to the trail user, and 3) results in the least possible environmental impact of all alternatives considered. However, Existing Conditions significant challenges are presented by the need to acquire public access rights for the trail to cross numerous privately owned properties. Concept Plan Concept Implementation E - Implementation of the trail is recommended to occur in three parts: • Part : Implement the Canyon Trails recommended in Ellison and Sandrock canyons • Part 2: Implement the Mission Valley Urban Trail elements needed within Mission Valley • Part 3: Collaborate with other stakeholders and planning processes to identify the best solution for a non-vehicular bridge and associated park space at the San Diego River crossing. This study recommends that the San Diego River Conservancy Board and the California Coastal Conservancy Board move forward with the recommended work, as outlined in Section 4 of this report, as quickly as funding and land acquisition efforts allows. Section of this study provides background information relevant to the project area and outlines specific goals and objectives for the Tributary Canyons Project. Section 2 provides an overview of the existing conditions within the project area, including natural resources, ownership patterns, existing trails, and similar information. Section 3 presents a detailed view of the recommended alignment and associated amenities, such as trailhead, wayfinding, habitat restoration, and interpretive elements. It also includes a discussion of possible solutions for the proposed non-vehicular bridge over the San Diego River. Section 4 summarizes the implementation strategy for the project. It includes recommendations for phasing of work and obtaining special studies, construction drawings, permits, public access agreements, and CEQA approval. It also includes preliminary cost estimates and funding strategies for the project. introduction & background 1 he City of San Diego has a relatively unique Turban structure, defined in large part by an ex- tensive network of open space canyons interwoven with developed urban neighborhoods. The canyons afford the City and its residents a variety of benefits, Summary Executive including visual interest, a sense of definition for the boundaries of neighborhoods, environmental values (water quality, flora and fauna habitats, wildlife cor- ridors, etc.), and opportunities for recreation and an intimate connection with nature. Much attention and effort has been given to identifying ways to preserve and enhance each of these benefits, from regional habitat management plans such as the Multiple Species Conservation Plan (MSCP) to wa- tershed-level plans, County-wide trail planning, and site-specific projects. 1.1 San Diego River Corridor Introduction & background Vision As one of the region’s major river corridors, the San Diego River has been the focus of a substantial planning effort over the past decade. The San Diego River Park Foundation (SDRPF), San Diego River Conservancy (SDRC), San Diego River Coalition, and City of San Diego (City) have completed a number of plans and projects that have both set a vision for the San Diego River corridor and taken great strides toward realization of that vision. The vision developed by each of these organizations shares several general goals: • Preserve and enhance cultural history Existing Conditions • Maintain and improve the river’s flood plain for flood capacity and water quality • Preserve and enhance natural habitat • Expand and connect recreational opportunities • Enhance public awareness through education and interpretation The planning work completed to date focuses most heavily on the 52-mile river corridor itself as a major regional linear open space backbone.