Confluence Park

Along the bank of the San Antonio River, Confluence Park is a living laboratory designed to broaden visitors’ understanding of south Texas ecotypes and the impact of urban development on local watersheds. A destination for learning and recreation, the park is part of the country’s largest environmental restoration project and an accessible gateway to outdoor activity. Situated at the junction of the San Antonio River and San Pedro Creek, the design reflects the idea of confluence. The park’s shaped lands represent the convergence of ecotypes, while the central pavilion’s concrete petal structures draw inspiration from plants that funnel rainwater to their roots.

In collaboration with Matsys.

Parks are places that should be architecturally aspirational to introduce great design to a broad swath of the population. Confluence Park does just that. Design Award Jury

Texas Society of Architects

The conversion of a former blighted industrial laydown yard into a public amenity, designed to be sustainable and low impact and with thoughtful place-making in mind, has had a deep and forward-facing impact on citizens, visitors, and students. While the client’s original intent was to provide a river access portal delivering exceptional outdoor educational programming, the project has become something bigger—a destination for the region and San Antonio community. Since opening in March 2018, the park has welcomed more than 32,000 students and registrants from over 350 programs, 70 schools across 11 districts in Texas, and 75 nonprofit partners.

Confluence Park is brought to life by rainwater. Using the biomimetic principle of looking toward nature for inspiration, the pavilion geometry is inspired by plants’ use of doubly curved fronds to cantilever and collect rainwater and then redirect it to the root stem. The concrete “petals” were formed to collect rainwater and funnel it into a central underground catchment basin, which is predicted to collect around 825,000 gallons of rainwater each year and can hold up to 100,000 gallons below the surface. Rainwater is filtered through alluvial soils, preventing any contaminated runoff from entering the San Antonio River, and is then used for sewage conveyance and irrigation.

The multipurpose Estela Avery Education Center building houses park amenities and a classroom/event space that opens to the pavilion, blurring the lines between indoors and out. A green roof provides thermal mass for passive heating and cooling, while a solar photovoltaic array is intended to produce 100% of the park’s energy needs. This low-lying building was designed as a dynamic juxtaposition to the pavilion—the board-formed concrete walls are highly textured compared to the smooth, fiberglass-formed petals, and the more geometric forms contrast with the curves of the pavilion.

PROCESS

Petal Construction

The construction of the concrete petals began with the fabrication of their fiberglass formwork in Oakland, California.
The formwork was shipped to the site in three segments and assembled for the concrete pours. Three casting stations were constructed, one for each type of petal (A, B, and C).
The concrete was cast into the formwork, then the exposed concrete was broom finished, cured, then carefully lifted into place.
The formwork was reused for all 26 petals – 20 at the main pavilion, and three satellite pavilions that consist of two petals each.