MEETING DATE: March 22, 2017 PREPARED BY: DEPT. DIRECTOR: Jim Gilliam, Arts Administrator. Jennifer Campbell

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1 MEETING DATE: March 22, 2017 PREPARED BY: Jim Gilliam, Arts Administrator DEPT. DIRECTOR: Jennifer Campbell DEPARTMENT: Parks and Recreation CITY MANAGER: Karen P. Brust SUBJECT: San Elijo Lagoon Double Track Project Aesthetic Elements RECOMMENDATION: 1) Authorize the Commission for the Arts to work with SANDAG to develop a recommendation for aesthetic elements on the proposed retaining wall, included in the San Elijo Lagoon Double Track Project. 2) The City Council work with SANDAG on the proposed aesthetic elements on the rail bridge bent caps, and recommend the inclusion of the CARDIFF motif on the bridge. STRATEGIC PLAN: This item applies to the Arts and Culture focus area. FISCAL CONSIDERATIONS: There is no fiscal impact associated with this Agenda Report. BACKGROUND AND ANALYSIS: The San Elijo Lagoon Double Track (SELDT) project will add a second track, east of the existing track, within the vicinity of San Elijo Avenue, where there is an existing slope, thus necessitating the installation of a retaining wall. Architecture treatment, aesthetic elements, and concrete coloring is proposed to match the retaining wall treatment agreed upon for the North Coast Corridor through Encinitas. An example of a retaining wall in Solana Beach features a decorative top ribbon, random fluting, and colored concrete to match the future walls along the I- 5 Corridor in Encinitas, (Attachment 1). By the City Council authorizing the Commission for the Arts to work with SANDAG to consider the aesthetic elements for the retaining wall, which is necessary to prevent slope failure, it will be more reflective of the community s character. The Commission for the Arts has previous experience working with SANDAG to enhance North Coast Corridor projects in Encinitas. In March, 2014, the commission developed recommendations to improve the architectural aesthetics by the addition of artistic elements to the I-5 Widening Project. The recommendations were based on the culture of the community, historical perspective, and unique characteristics of the five communities of Encinitas Item 8E 1 of 12

2 Additionally, the SELDT project includes the expansion of the rail bridge over the San Elijo Lagoon. Proposed is a stamped design into the pre-cast concrete rail bridge bent caps received from SANDAG. The proposed CARDIFF design is intended to reflect community and nearby character, (Attachment 2). Council is requested to consider the proposed CARDIFF design, for the rail bridge bent caps, which commemorates the community. ENVIRONMENTAL CONSIDERATIONS: The action considered is exempt from the California Environmental Quality Act, (CEQA), because it is not a project under Section 15378(b)(5) of CEQA Guidelines. The action involves an organizational or administrative activity of government that will not result in the direct or indirect physical change in the environment. ATTACHMENTS: Attachment 1: Attachment 2: San Elijo Avenue Retaining Wall Memorandum SAN LOSSAN SELDT Bridge Cap Item 8E 2 of 12

3 San Elijo Avenue Retaining Wall Memorandum San Elijo Lagoon Double Track Project SANDAG CP Cardiff to CP Craven DRAFT March 15, Item 8E 3 of 12

4 Contents Introduction... 2 Existing Conditions and Proposed SELDT Wall... 2 Vegetated Wall Options Considered... 4 Conclusion... 6 HDR Item 8E 4 of 12

5 Introduction This memorandum is written in response to the City of Encinitas (City) request for San Diego Association of Governments (SANDAG) to provide further evaluation of the retaining wall parallel to San Elijo Avenue. The City requested a wall be considered which incorporates native plants built into the wall. Below are the photo examples provided by the City. Example Wall Photo 1 Example Wall Photo 2 This memorandum discusses the feasibility of installing a vegetated wall. Existing Conditions and Proposed SELDT Wall The San Elijo Lagoon Double Track project is adding a second track east of the existing track within the vicinity of the proposed wall (MT1 STA to STA ). The second track must be added east of the existing as any westerly track shift places the embankment into the San Elijo Lagoon inlet channel, and negatively impacts tidal exchange into the lagoon. Therefore, the second track will be placed closer to San Elijo Avenue, where there is an existing slope ranging from 2:1 slope to 1:1 slope. The aerial photo below shows the horizontal constraints between San Elijo Avenue and the San Elijo Lagoon inlet channel. SELDT Existing Condition - Horizontal Constraints HDR Item 8E 5 of 12

6 The photo below shows the vertical constraints from left to right, San Elijo Avenue, the slope and future wall location, the existing railroad track, and the slope down to the San Elijo Lagoon inlet channel. SELDT Existing Condition Vertical Constraints The proposed retaining wall will cut into this slope thereby creating space for the second track. Due to the minimal distance between San Elijo Avenue and the railroad, a soldier pile wall with concrete lagging was proposed. This is the only option which keeps the wall within the NCTD right-of-way. Architecture treatment and concrete coloring is proposed to match the retaining wall treatment agreed upon for the North Coast Corridor through Encinitas. The image to the right shows the finish of the proposed SELDT wall. The photo shows existing retaining walls with similar architectural treatments constructed in Solana Beach. SELDT Proposed Wall The wall features a decorative top ribbon, random fluting, and colored concrete to match the future walls along the I-5 Corridor in Encinitas. The proposed wall has cable railing without the top handrail shown in Solana Beach Wall, to minimize view impacts. HDR Item 8E 6 of 12

7 A cross-section of the proposed SELDT soldier pile wall at STA is provided below. This location shows where the wall is closest to City s right-of-way and most horizontally constrained. Example Retaining Walls with Similar Architectural Treatment in Solana Beach SELDT Proposed Soldier Pile Wall Cross-Section at STA Vegetated Wall Options Considered The Example Wall Photo 1 MSE Wall The City of Encinitas provided photos of vegetated walls included in the introduction paragraph. The Example Wall Photo 1 shows a planted MSE wall similar to products available from This manufacturer provides living walls such as stackable blocks or a wire wall which are irrigated and fully plant-able. These types of walls require the face of the wall to be attached to geotextile reinforcement or straps which are embedded into the soil behind the wall. Typically, the embedment of the soil reinforcement extends 90% of the wall s design height. Therefore, this type of wall requires extensive excavation and temporary shoring to construct the backfill and layer the soil reinforcement. HDR Item 8E 7 of 12

8 A cross-sections of the Filtrex Earthbloxx wall at the same location, STA , is provided below. The Example Wall Photo 2 Crib Wall SELDT Proposed Soldier Pile Wall Cross-Section at STA The Example Wall Photo 2 shows a typical planted Caltrans Crib Wall. At our Design Height of up to 18 and loading from San Elijo Avenue, a CALTRANS Type C Crib wall from Standard Plan C7A would be required. The wall section is 19-4 deep and would require construction excavation and temporary shoring similar to the MSE Wall option above. HDR Item 8E 8 of 12

9 Conclusion The vegetated wall options require additional clearance from the proposed second track for temporary work during installation and for the permanent structure. Temporary Condition In the temporary condition for the vegetated walls, a full closure of San Elijo Avenue would be required for excavation. The temporary shoring will also require tie backs, which will extend beyond the City s right-of-way and into the nearby private properties. A temporary easement would be required to install the temporary tie-back shoring wall. Within San Elijo Avenue there is a 12 gas line and 12 water line which would require relocating. There is also a 15 sewer which may require relocating depending on verification of its location. The added costs to address the utilities for these temporary or permanent works would need to be considered. Final Condition The Vegetated walls typically require a batter for stability and for vegetation to thrive. This batter will place the structure itself outside of the railroad right-of-way. A permanent easement will be required with the City; and San Elijo Avenue may require reconstruction with reduced lane widths to accommodate a guard rail. A ditch will be required at the bottom of wall near the track to accommodate the additional runoff from irrigation. The track here is sloped to the west; without a ditch, the addition runoff would travel through the ballast, negatively impacting the proposed track section. Additionally, the vegetation would require maintenance to keep growth and fallen debris from encroaching into the train envelope. A license agreement would be required to allow City staff inside of the Railroad right-of-way for maintenance. Due to the minimal walkway widths and clearance, any maintenance activity will be difficult and dangerous. Schedule The SELDT project construction started in February 2017, and the retaining wall is one of the first items of work to provide room for the first phase of track work. The wall excavation cannot begin until the gas line is relocated, which will take a minimum of 12 months. During this 12 month timeframe, the funding for the new wall will need to be secured, the design finalized and approved, and material purchased. After the gas line is relocated, the wall construction could be completed in approximately 6 months. Therefore, all track improvements could be delayed up to 18 months. The contractor would likely be placed on hold and would remobilize, incurring additional costs. The delay in project schedule may impact permits, funding, and public expectations. HDR Item 8E 9 of 12

10 Recommendation Due to the costs associated with temporary shoring, excavation, utility relocation, schedule delays, and maintenance safety concerns, we recommend utilizing the SELDT proposed wall with architectural treatment to match the I-5 corridor. The area above the wall could be planted with hanging growth should NCTD agree to this approach. The photo below shows an example of hanging growth on a retaining wall. Example of Hanging Vegetation (Photo credits to Ken Steinhardt, The Orange County Register) The southern 103 portion of the wall consists of a Caltrans Type 1 retaining wall; at this location, the design height and distance from the gas line may make a vegetated wall possible and can be investigated further. HDR Item 8E 10 of 12

11 LOSSAN San Elijo Lagoon Double Track Bridge End Cap Stamp Design Option A: Text-only Typeface: Museo Slab Attributes: Strength, friendliness, and readability 66" 60" Conceptual Rendering Only 12/18/ Item 8E 11 of 12

12 LOSSAN San Elijo Lagoon Double Track Bridge End Cap Stamp Design Option B: Illustrated pelicans, rough concept to be refined if chosen 66" 60" Conceptual Rendering Only 12/18/ Item 8E 12 of 12