Sustainable Construction Practices

Warm mix asphalt can be produced at lower temperatures than traditional hot mix asphalt, reducing energy use and emissions. It can also incorporate recycled or waste materials and is easier, faster, and often more durable to install. This practice is already common locally: 72% of street and drainage projects in San Antonio’s 2022 Bond directed the use of warm mix asphalt in their plans.

Recycled asphalt pavement can also be used in non-surface roadway layers. Benefits include:

• Stronger, more stable pavement that better resists water infiltration and high temperatures
• Improved traction during wet conditions
• Less construction material sent to landfills
• Reduced energy use and carbon emissions
• Conservation of natural resources and support for local businesses

This approach has been used on projects including Dorsey Drive, South Brazos Street, Valley Hi Area Drainage, Seeling Drainage Phase 4, Evans Road Phase 1, and Eisenhauer Road Drainage Phase 1A.

Replacing bermudagrass and St. Augustine grass with native grasses and other native plant species can improve project performance while supporting the surrounding environment. Deep-rooted native plants help soils absorb more water, capture carbon, improve air and water quality, and reduce urban heat. They also require less mowing, irrigation, and fertilizer while supporting wildlife, local businesses, and opportunities for education and cultural connection.

Native landscaping has been incorporated into projects such as North New Braunfels Phase 2, Brookside Outfall, the South Zarzamora Overpass, Covel Road, District 6 Intersection Improvements, Quentin Drive Alley, Oak Haven Area Streets, and Bulverde Road.

All 2022 Bond projects will use locally manufactured, lower-carbon cement that requires less energy and fewer raw materials to produce while providing greater durability and lower long-term maintenance needs. The City also encourages construction and demolition debris to be recycled rather than sent to landfills.

Contractors must provide environmental impact reports for construction products before work begins, helping the City evaluate each project’s carbon impact and identify lower-impact materials for future streets, parks, and buildings. These practices are being applied to projects including South Pine Phase 2, Dorsey Drive, Covel Road, Valley Hi Area Drainage, and Topperwein Road.

Municipal building projects can incorporate features that improve comfort, reduce energy use, and prepare facilities for extreme weather and future technologies. These features include:

• Cooling systems designed to withstand heat waves
• Energy recovery systems that use cool exhaust air to pre-cool incoming air, reduce utility costs, manage humidity, and help prevent mold
• Reflective “cool roofs” that absorb less heat
• Electrical systems designed to accommodate future solar installations
• Infrastructure that can support electric vehicle charging stations as funding becomes available

Examples include the District 1 Multi-Generational Center, which will also feature sustainable rain gardens to capture runoff, while cool-roof requirements are applied to municipal buildings through the City’s building code.

DRS is building the tools, partnerships, and policies needed to make sustainable construction practices a consistent part of San Antonio’s capital investments.

• DRS is working with CDD and PWD to integrate resilient construction materials into capital and Bond projects.
• A data library and project-specific scorecards have been developed to evaluate different types of infrastructure.
• A how-to guide is underway to help City teams use these tools effectively.
• Lastly, the City is identifying policy opportunities informed by other cities, such as bond resolutions, procurement standards, and staff training.