Banking on a Rainy Day
February 05, 2019 / Carmon McCain
Article by Carmon McCain
Persons traveling through the busy intersection of Southwest 45th Avenue and Teckla Boulevard in Amarillo may take a moment to notice the banking center built there about seven years ago. However, few realize that it is home to one of the city’s larger commercial rainwater harvesting installations.
Construction of the FirstBank Southwest (FBSW) Western Banking Center begin in 2012. Bank officials and Landscape Architects agreed that they could do more to conserve water — even though xeric landscaping was a major component in the original landscape plan.
Before construction, the 36,252 square foot site allowed 100 percent of rainwater runoff to enter the City of Amarillo’s storm water system. Addition of an on-site rainwater harvesting system helps reduce the amount of water used for landscape purposes and lessens storm water runoff in this flood-prone area.
“Residents of our area are Texas tough and Panhandle proud. When you think about it, we are doing the same thing that our early predecessors did. They had to capture water (in cisterns) in order to maintain a viable lifestyle,” said Smith Ellis, Chairman of the Board, Chief Executive Officer, and President of FBSW.
It was hot and dry when I visited the bank in late August. David Pace stood in a doorway and pointed toward the tan-colored pavers around the building. He has served as FBSW properties manager since 2009.
“Every so often, people will ask to see the system during a rainfall event. I like to watch the expression on their faces as rain flows across the parking area and eventually disappears into the permeable paving system,” he said.
Rain falls upon the parking lot and the building’s metal roof. Downspouts channel water from the roof to the pavers. Once below the pavers, it flows through gravel backfill into 530 linear feet of perforated pipe. The pipe conveys water into an underground tank.
“The tank is basically a rigid ‘milk crate’ with a non-permeable envelope around it,” says Jason Habeger with Turner LandArchitecture in Amarillo. The company designed the rainwater harvesting system.
“This type of tank doubles the storage capacity at a lesser cost. The system, as a whole, is not from one company. It is a combination of multiple rainwater collection methods available from different sources. Each can be used independently – it just depends upon what the customer wants to accomplish with their design.”
The paver system base can hold up to 12,000 gallons of harvested rainwater. An additional 14,600 gallons of rainwater can be stored in the underground tank. This gives a potential storage capacity of 26,600 gallons. That is the equivalent of 99.6 percent of the rainfall collected from a two-year storm event.
“This is not a self-sustaining system — even though we have the potential to collect a large amount of water. For example, our last major rainfall was in September and we were out of water by February. There are backup connections to use city water for the landscape, if needed. This still saves water because of the xeric landscape. We are equipped to handle the ebbs and flows of rainfall events,” said Pace.
The banking center contains 7,720 square feet of designed landscape area. The perimeter includes a rain garden/swale with boulders from Marble Falls, decomposed granite mulch, and river cobble. This allows rainwater to percolate into the soil.
Planting the area in tall fescue would require an application of approximately 171,661 gallons of water with an automatic landscape sprinkler system during the growing season.
Designers incorporated a point source drip irrigation system for efficiency and flexibility. Each bedded plant receives about one gallon of water per hour through one to five strategically placed emitters. Trees receive one gallon of water per hour through two bubblers.
The xeric landscape, combined with the drip irrigation system, will reduce landscape water use by 60 percent as compared to a traditional tall fescue lawn.
Both Habeger and Pace agree that this project has increased awareness of the use of xeric landscaping. It also prompted a change in the City of Amarillo’s landscape ordinance with the addition of a recommended plant list.
“People in Amarillo are starting to understand that they can have an attractive landscape with native drought-tolerant plants, rather than relying on traditional turf and trees. This project has inspired them to ask how they can accomplish similar results and be a good steward of our natural resources,” said Habeger.
Ellis agrees that it is important to lead by example.
“This rainwater harvesting project has exceeded our expectations. It was a costly project – but it is worth it for several reasons. It enhances the community in which we are a corporate partner. Even more importantly, it highlights some of our water issues and provides a way to combat those problems. It is the right thing to do – even though it is the pinnacle of a small effort toward water conservation. Believe me, this isn’t the last drought that we will ever experience,” he said.