The Hemisfair Park Area Redevelopment Corporation (HPARC) is creating a place that fits the history, life, and character of San Antonio in the heart of downtown. The park’s water re-use system will be a model of water sustainability in keeping with the citizens of San Antonio’s long tradition of water stewardship.
Background
To look at the design for Civic Park, you must first look at the region’s rich landscape character, geology, and natural history.
San Antonio sits on the 98th Meridian, at the border between the semi-arid climate of the western half of the state and the sub-tropical climate of the east, and also along the fault zone of the Balcones Escarpment that divides the state east-west (Figure 1).
This dynamic fault zone marks the transition from the Hill Country and Great Plains to the northwest and the Blackland Prairie and Coastal Plains to the southeast. This confluence of conditions gives the city and its surroundings a distinct character.
To the north of downtown San Antonio, the Hill Country provides changes in elevation and long open vistas. The limestone of the rolling hills has been sculpted by water over time, creating a rich mixture of exposed faces and lush valleys. The Balcones Escarpment is characterized by a series of faults that have created a dramatic rift between the Hill Country and the coastal plains to the southeast. Water flowing from the Hill Country often passes into these faults and into the aquifer below, creating natural sinkholes and disrupted streams. Though now compromised, the Blackland Prairie once defined the landscape south of the Balcones Escarpment. This gently rolling land had a thick accumulation of sediments that supported a grassland ecology.
The Civic Park design concept borrows from and refines these regional geologic and water characteristics into a park vision that uses water elements to connect various park precincts which are evocative of the greater region (Figure 2).
The design of Civic Park will serve as a metaphor on two levels to educate the public of our historical precedence of being good water stewards and to demonstrate how this resource can be recycled on-site.
Historic Precedence of Water Use
Five connected water elements in the new park design demonstrate how our early settlers used the San Antonio River flow from its headwaters. By damning the river in the current zoo area, they could transport water via the extensive acequia system to irrigate their fields through flooding and ultimately return water into the river. The design envisions a Source Plaza at the corner of Market and South Alamo Streets (Civic Park Phase II) with a dramatic fountain feeding a water trace that will flow beside an 1100-foot pedestrian promenade.
Near the southeast edge of the park, there will be a series of five rectangular springs created from CDC-milled limestone blocks. These are modeled after the numerous Hill Country riverbanks that the forces of nature have carved for millennia. Each spring is unique and has multiple seeps that allow water to flow over the limestone into small pools where visitors can wade.
Water is a precious resource in San Antonio, and its scarcity will only worsen in the coming years. The Water Supply Sustainability Index notes Bexar County as one of several Texas counties that will have extreme water stress (Figure 3).
However, throughout the city’s history, there has been a legacy of engineering innovation and water exchange to maximize the potential of limited water resources. The symbiotic relationship between the Henry B. Gonzalez Convention Center adjacent to Civic Park holds the potential to take a new step into the future of this legacy and exemplify San Antonio’s ambition to demonstrate leadership in water sustainability. Rather than focusing solely on limiting the presence or use of water within the Civic Park (for water features, landscape irrigation etc.), water is used for maximum impact within this critical public space, albeit found nuisance water rather than the city’s precious municipal potable water.
This concept is in keeping with a new water paradigm that is becoming more common nationwide. Water resources within a new project are recycled within the facility, thus lessening the demands on the City’s centralized utilities (Figures 4 and 5).
Civic Park’s Environmental Sustainability
Hemisfair is collecting nuisance water from a sump pump at the Henry B. Gonzalez Convention Center that collects groundwater from around the perimeter of the basement and air conditioning condensate water that would typically flow to the City of San Antonio’s stormwater collection system. The water flow averages about 28 gallons per minute, and after it is collected, it will be filtered to remove particles greater than 5 microns and stored in the new 40,000-gallon underground cistern.
This water will be used for irrigation and makeup water for water features. As the source of this water isn’t provided by the local utility from the aquifer, the park will not be required to restrict watering during drought conditions which are common throughout the city.
When the park opens in the fall of 2023, Civic Park will have over two hundred trees, one and a half acres of turf grass, and nearly a thousand plants and shrubs. With this system, Hemisfair will have a permanent water supply to keep the park green year-round, keeping the park beautiful.
Water for the eight water features in the nine-acre park will also come from the water cistern. This water will be piped from the cistern to an underground pump/filtration room, where it will be brought up to near swimming pool quality through sand filters and the addition of chemicals and UV light. The water in these features will be recycled multiple times daily through the filters, with makeup water added as needed from the storage cistern.
To educate the public on this unique water use, we will install interpretive signage telling the story of this water usage and how they incorporate similar solutions at their homes and businesses through A/C condensate and rainwater collection.
Conclusion
The water re-use system for the new Hemisfair Civic Park represents an opportunity to showcase water self-sufficiency on a new scale. The project will demonstrate that even in these water-stressed times, it is possible to have beautiful public spaces that require water for their operation as long as that water is recycled from within the project and not imposing an unnecessary strain on the environment’s natural resources. Also, the relationship between Hemisfair’s Civic Park and the adjacent convention center will represent new creative ways of thinking and a collaborative spirit is necessary to become more water efficient and move into a modern water paradigm
