New Longhorn Dam Bridge

30% Design Virtual Open House

Welcome 👋 

 Austin Public Works  Austin Transportation , and  Austin Parks and Recreation  are partnering to design and construct a new wishbone-shaped pedestrian and bicycle bridge over Lady Bird Lake near the Longhorn Dam. Austin Public Works’  Urban Trails Program  is managing this project through all phases of design, construction, and inspection. 

Thank you for visiting our 30% design virtual open house. Scroll down to learn about this project and take a survey to share your feedback with the project team.  

To request a hardcopy of this open house by mail, please email  MobilityBonds@austintexas.gov  or call (512) 974-7182. 

Project Background 🌉 

Between 2003-2018, several City of Austin plans identified a need to improve walking and biking near the Longhorn Dam bridge. These plans included the  Bicycle Plan  Urban Trails Plan , and  Holly Shores Vision Plan  Learn more 

In 2018, the City allocated  2016 Mobility Bond  funds to create a Preliminary Engineering Report (PER). The goal of the PER was to study the possibility of a new pedestrian and bicycle bridge over Lady Bird Lake. The report also studied options for  near-term improvements  to South Pleasant Valley Road over the Longhorn Dam bridge. 

In 2019 Austin Public Works  and  Austin Transportation  shared five options for the bridge design. A  wishbone-shaped  design received the most community support. 

In 2020, the City published a final  Preliminary Engineering Report  for the “wishbone” bridge design. Later that year, Austin voters approved the  2020 Safety and Active Transportation Bond.  The bond included $15 million for the design and construction of the new bridge. 

PER 📋 

Prior to construction, major capital projects go through two key phases: preliminary engineering and design

During preliminary engineering, the project team uses technical analysis and community input to create a project concept. A Preliminary Engineering Report (PER) reflects an initial outline of recommended improvements. PERs for Urban Trails Program projects also recommend a specific project alignment. Multiple City departments review a PER to ensure that a proposed project follows all relevant plans, policies, and standards before a design process begins.

Community feedback informed the preliminary project design reflected in the PER, which included:

  • A wishbone-shaped pedestrian and bicycle bridge across Lady Bird Lake spanning .43 miles with an average width of 30 feet 
  • Three points of connection to the existing Butler Hike and Bike Trail: Longhorn Shores, Holly Shores, and the unnamed peninsula near Holly Shores 
  • A shaded plaza with seating, lighting, and plantings at the center of the bridge 
  • A new, wider trail underpass beneath South Pleasant Valley Road to accommodate more users, address drainage issues, and add lighting 
  • Removal of existing pedestrian bridge connecting the unnamed peninsula to Holly Shores to allow room for the new bridge abutment and landing 
  • Removal of existing parking lot at Holly Shores to allow room for the new bridge abutment
  • New on-street parking spaces, sidewalk, parkland improvements and landscaping along south edge of Canterbury Street

Guiding Principles ✅ 

The project’s Preliminary Engineering Report (PER) also established a set of  Guiding Principles of Bridge Design . This design framework is guiding decision-making throughout the design phase. 

The project’s Guiding Principles include: 

  • Safety & Accessibility: Design the bridge and its connecting trails to the highest standards of safety and accessibility. 
  • Convenient Connections: Provide a bridge alignment and connections that create direct and convenient travel paths for both commuters and recreational trail users. 
  • Environment & Landscape: Design the bridge to complement and enhance the environment, park, river and the natural landscape. 
  • Friendly & Engaging Deck Space: Design the bridge deck, furnishings, and connecting trails and spaces to create a high-quality user experience. 
  • Cost-Effective Structure: Design the bridge structure to be as cost-efficient as possible, prioritizing the user experience at the deck level. 

Design Phase 📐 

During the design phase, the project team continues to gather community input and coordinate across City departments as they refine project plans. Major capital projects go through multiple phases of design – from 30% to 60% to 90% complete – before they are finalized and the project goes to bid for construction. Tackling the project design in phases allows for timely public input and revisions at key stages of design development. 

The New Longhorn Dam Bridge project is currently at 30% design

30% Design Updates 🗺️ 

The project team has taken the concept for this new bridge from the PER and refined the design based on community input and City staff feedback. Scroll down for an overview of new design details included in the 30% design. Then, let us know if you think we’re on track through the project survey. 

Note: the illustrated renderings below are conceptual and subject to change. 

Project Limits

Bridge and Plaza Area 

  • Paving patterns on the bridge surface to separate areas where people can stop and gather from a path for people traveling across the bridge 
  • LED pole-mounted lighting to provide energy-efficient, low-maintenance, night sky and wildlife-friendly lighting for comfortable 24-hour use of the bridge  
  • Steel trellis structure to guide the growth of vines to create a natural shade cover in the plaza area 
  • Planters at the foot of steel trellis structure to support vine growth 
  • Shade sails atop the steel trellis structure to provide shade for bridge users until vines are mature 
  • Wood benches to provide seating at plaza overlooks 
  • Galvanized steel handrails along the entire bridge 
  • Trash and recycling receptacles on each bridge leg to prevent litter and pollution 

Pleasant Valley Underpass 

  • New, larger underpass constructed of concrete arches 
  • 16-foot concrete trail within the underpass to connect the Butler Hike and Bike Trail, Country Club Creek Trail, and Roy G. Guerrero Colorado River Metropolitan Park 
  • Two 7-foot drainage swales composed of mortared rock bordering the concrete trail to collect stormwater 
  • Ground-mounted lighting to illuminate the underpass for safety 

Canterbury Street Parkland 

  • Preservation of the Roy Montelongo Scenic Overlook, gazebo, and water fountain 
  • New trailhead/warm-up area with granite paving, fitness equipment, bike racks, benches, and a water fountain 
  • New ADA-accessible picnic area with granite paving, three tables, and trash and recycling receptacles  
  • New concrete trail connection from the bridge landing to existing sidewalks on Canterbury Street and shared use paths on South Pleasant Valley Road 
  • Landscaping improvements, including planting new trees, native grasses, and wildflowers 
  • On-street parking, including a van-accessible ADA parking space, along south edge of Canterbury Street 
  • Galvanized steel handrails along parkland between the bridge landing and South Pleasant Valley Road for safety 

30% Design Survey 📝 

The project team wants to hear from you! Are we on the right track?  

Share your feedback: take our survey by March 24, 2022

Art in Public Places 🎨 

By City of Austin ordinance, 2% of eligible capital improvement project budgets are allocated to site-specific artwork. The City’s  Art in Public Places program  (AIPP) collaborates with residents and artists to incorporate public art into major capital projects. 

Austin Public Works hosted a virtual public meeting on Wednesday, March 9, 2022 on Zoom. At the meeting, AIPP gathered community input on public art for the New Longhorn Dam Bridge project. Attendees were asked to help define inspiration and goals that will inform the artist selection process.

For more information about this Art In Public Places project, contact Anna Bradley at Anna.Bradley@austintexas.gov or (512) 974-7841. 

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