Landscaped plaza to feature native plants, urban-style tree pits, and innovative stormwater reuse
As recently as 2013, a decorative fountain located on the Fairfax County Government Center campus shot jets of water 20 feet into the air during the warm months of the year. Employees working at the Pennino and Herrity Buildings would meet and eat next to the soothing sounds of splashing water. A whimsical, cooling mist provided relief on hot summer days, and ephemeral rainbows, formed as the sun’s rays refracted through the towering bursts of water, provided a colorful visual display.
But, as often as not, the fountain was shut down for maintenance and repairs. The leaking pond often required resealing, and when the pump and chemical feeder failed, the stagnant pool filled with trash, leaves, and algae. The adjacent waterfall was fed through a circular pump that pulled water from the stormwater retention pond, but the pump clogged often and eventually stopped working altogether.
The cost to fix the fountain ranged from $75,000 to $150,000 each time it malfunctioned, so some years the pool remained empty, which it has for the past six years. What had been a decorative amenity had become an eyesore and a financial liability. Something had to be done.
One idea, formed during the lean budget years following the Great Recession, was to simply fill in the pool and seed it with turf grass. This solution would’ve eliminated further maintenance costs as well as the annual water bill, which had peaked at nearly $700 per year for more than 170,000 gallons. While this idea had merit, there was a problem. When the property was rezoned for development in the mid-1980s, inclusion of a water feature was required. Filling in the fountain like an unwanted backyard swimming pool was not an option.
A committee of employees from several county agencies was formed to identify possible solutions for replacing the fountain. Early on, a rendering of a plaza with seating and sunshades was shared, but there wasn’t any budget for such a grand redevelopment plan. The former Office of Community Revitalization, now the Department of Planning and Development, reached out county employees to hear their suggestions. Recognizing that the workforce wanted an improved gathering place, the committee went back to the drawing board. The challenge was to identify a solution that was decorative, functional, and sustainable. “Eventually, with a lot of input, the plan to build a rain garden amenity at the site was decided upon,” said former Public Works director James Patteson.
The decision to convert the decaying fountain into a rain garden solved the funding problem – the stormwater management project would be paid for with Stormwater Service District fees – but the requirement for a water feature remained. The late John Palmer, a landscape architect in the Stormwater Planning Division before his sudden passing in 2018, proposed an innovative idea: use plants to mimic the movement of water. His design included natural planting areas on both sides of the Herrity entrance road containing wildflowers, tall breezy grasses, and a few ornamental trees to unify the two spaces. Where the fountain used to be, Palmer envisioned a small, circular plaza made of permeable pavers, bricks which allow water to infiltrate the soil below. Outdoor seating on the plaza would create a welcoming space for county employees and visitors to rest in the shade and enjoy the sights, sounds, and scents of a native rain garden, such as rustling grasses, buzzing bees, and aromatic flowers that bloom throughout the year.
"The project is a wonderful example of how a space redesigned for stormwater management can also be designed as a space for people, providing a place for social interaction and respite," said Suzie Battista, senior program manager, Urban Centers Section, Department of Planning and Development.
Palmer’s initial design was further developed to highlight the benefits of conservation landscaping, or the use of native plants that require less water and maintenance, support wildlife habitat, and improve water quality. As the plan evolved, the fountain replacement project became an opportunity to demonstrate stormwater management best practices and to test emerging green infrastructure technologies.
Two of the most interesting new ideas will be installed underground and out of sight. First, Palmer’s design includes approximately 587 cubic yards of crushed glass (60 truckloads!) to treat stormwater runoff that percolates through the filter medium. Crushed beer and wine bottles and salsa and jelly jars will capture pollutants before the runoff reaches the adjacent retention pond, which feeds tributaries of Difficult Run and, eventually, the Potomac River. The glass to be used is collected throughout the region in purple, glass-only recycling containers and then crushed for reuse applications at the landfill complex in Lorton, Va.
The second hidden feature, a 15,000-gallon storage tank buried beneath the plaza, will capture some of the rainwater flowing off the Herrity parking garage. Municipalities are facing challenges caused by more intense rain events that deliver a high volume of water in a short time. Cisterns are increasingly seen as a good way to capture and slowly release the runoff from residential and small commercial lots.
“The project has served as a great educational opportunity for county staff and our design and construction partners to learn more about these types of green stormwater infrastructure,” said project manager Catie Torgersen, Stormwater Planning Division.
A small pump that uses a fraction of the energy that the former fountain’s pump used will tap the underground reservoir to create a decorative bubbling fountain in the center of the plaza. Water will gently cascade down the face of a monolithic stone. “The bubbler fountain was chosen as a low maintenance approach to meeting the proffer requirement for a water feature at the Herrity site,” said Torgersen. “It is a visible representation of the underground cistern and rainwater harvesting.”
Another stormwater storage system to be tested is bioretention tree pits like the ones used in urban streetscape projects. The idea behind the pits is to use captured stormwater to irrigate trees. Urban areas, such as Tysons, don’t leave much room for stormwater storage, and there are numerous stresses that can prevent trees from achieving the county’s 10-year canopy goal. Palmer reached out to the Urban Forest Management Division about installing bioretention tree pits right outside UFMD’s offices, where urban foresters will be able to monitor their performance without needing to drive to busy commercial areas. Specifically, they’ll be able to see how road salt, debris, and other pollutants affect the health of the trees. The hope is to identify potential problems and improve the design of the pits for future applications. “We want to be better stewards of the county’s stormwater and tree canopy responsibilities,” said urban forester Jay Banks.
The new rain garden will be the latest stormwater management best practice on display at the Government Center campus. The adjacent stormwater retention pond was upgraded to increase the pond’s storage capacity in October 2018. An internet-based system was installed that automatically lowers pond levels before heavy rain events, and a floating fountain will be installed next spring to aerate the water and stabilize pH and water temperature. The decommissioned waterfall was replanted with native plants and wildflowers, which bloomed throughout the summer and into fall. A 25,000-gallon cistern buried behind the Public Safety Headquarters stores rainwater from the building’s vegetated green roofs, and infiltration trenches, bioretention swales, restored streams, rehabbed ponds, permeable pavers, and a native meadow work together to treat runoff from the campus and surrounding neighborhoods.
News coverage of climate change, urban flooding, and growing water scarcity has heightened awareness of the need to slow down and store runoff and use captured rainwater for beneficial uses where possible. Decorative fountains that rely on clean drinking water and power from electric pumps are falling out of fashion because they are perceived as wasteful.
“The proposed modifications provide stormwater management benefits, educate the community and county staff, and provide a beautiful, usable outdoor space that is generally low maintenance,” said Torgersen.
John Palmer’s role in designing an aesthetically pleasing, modern stormwater management facility will be commemorated with a tree dedicated to his memory. The Department of Public Works and Environmental Services is managing design and construction of the fountain replacement project, with estimated completion in late 2020.