Managing stormwater was the last thing developers in Athens, Ga., considered. During the past nine years, the community saw 11 percent population growth, stressing the undersized or failing infrastructure in the central business district and suburban areas.
The Athens-Clarke County (ACC) Department of Transpor-tation and Public Works had done piecemeal drainage and flood control projects for years, but without a capital improvement program.
Once developed in 2000, the program identified 203 flooding problems and 57 Level 1 (top-priority) problems. The county’s aggressive response earned them the 2003 Georgia Water & Pollution Control Association Stormwater Program of the Year award.
That year, stormwater management also received separate recognition and became ACC Stormwater. Within two years, community response to the stormwater education outreach program was so strong that voters approved a sales tax referendum raising $2.3 million annually for related projects.
Elected officials heard the message and continued supporting management plans containing water-quality features and flood control. With 70 percent of Level 1 problems solved, Athens can develop without threat of diminishing the community’s quality of life.
Making it bigger
Many Level 1 problems stemmed from a collection and conveyance system too small to handle the runoff from even minor storms. When it rained, highways in the gently rolling hills had ponds one-to-two feet deep in low areas, forcing road closures. Some affected areas were major collector routes serving hospitals, schools, and fire departments.
The Lumpkin Street corridor is one of two high-profile projects completed in recent years. This 1.2-mile collector-conveyance system connects to the central business district and to another commercial node. It is bordered by homes and the University of Georgia. The discharge end was upsized to 60-inch reinforced concrete pipe, and the upstream segment was enhanced by rain gardens, bioretention areas, and swales.
“Stormwater runoff from Lumpkin Street was conveyed to Tanyard Creek through pipes and small, square concrete culverts,” says Jason Peek, P.E., engineering administrator and manager of the stormwater program. “That segment of creek drains the heart of downtown Athens, and was impaired.”
Lumpkin Woods, the University of Georgia’s neglected arboretum, was the largest green space available for stormwater facilities. Peek, associates, and design consultant ARCADIS from Atlanta approached the university’s landscape architect staff to help plan their designs. They became so supportive that the university donated the property and now maintains the facilities.
Rain gardens
Water at the downstream end of the stormwater treatment train is detained in a micropool wetland with decorative granite retention walls and v-notch weir. A vegetative swale upstream promotes infiltration. A rock-lined swale farther upstream mimics a dry streambed to continue infiltration and reduce velocity.
Rain gardens were constructed at the intersection of Lumpkin and Baxter Streets, which have the second highest pedestrian count in the county. “We wanted the features to be highly visible and have an aesthetic, landscaped appearance,” says Peek. “The project showcased how we could handle stormwater issues and create something of value for the community. It built a lot of support for the program.”
Stormwater from the street flows through hood-and-grade inlets into sequential rain gardens constructed of permeable soil and lined with decorative stones to slow the flow. They also collect floating trash. Runoff then enters a brick overflow structure discharging to the underground stormwater system. The outfalls are in Tanyard Creek.
Since completion in 2005, university professors use the project to show landscape architecture students real-world examples of what they teach. Some environmental students monitor the effectiveness of the systems. Studies show an 80 percent reduction of TSS in contributing drainage.
Informing the public
The Lumpkin Street project involved major construction lasting more than two-and-a-half years. It reduced travel lanes, occasionally closed roads, and occurred next to commercial and small businesses. Handling its effect on the community was a major challenge. “We held three open forums and numerous one-on-one meetings with residents even before we were authorized to bid the project,” Peek says. “However, by building public support, elected officials felt that their constituents were satisfied with it.”
Peek’s construction progress updates enabled field employees to answer questions about traffic control changes or when construction would reach residents’ driveways or businesses. “The department published the cell phone numbers of project inspectors, but it was the one-on-one relationships we built that helped resolve issues before they grew into bigger problems,” he says.
Employees went door-to-door notifying residents the week before construction started in their neighborhood, then checked on them periodically. They worked with businesses two weeks in advance of construction, learning their delivery schedules and coordinating driveway closures. “We always emphasized the importance of stormwater management to control flooding and improve the environment,” says Peek. “Most citizens supported our efforts and tolerated the inconveniences.”
Baxter Street became the department’s second high-profile venture. Frequent flooding along that street blocked emergency vehicle access to a hospital, damaged commercial property, and closed the thoroughfare to traffic several times a year.
The major challenge was acquiring land for two detention ponds. “We had to make property owners understand how the final product would look and how it would control flooding,” says Peek. One method was using mockup drawings.
“We identified and replaced an undersized culvert, the primary cause of our flooding problems,” says Peek. “We also installed two Stormceptor systems (Imbrium Systems Corp.) to remove suspended solids and hydrocarbons.”
Stormwater ABCs
The county’s education outreach efforts range from K-12 school programs to workshops that help homeowners restore stream banks. A donation of plastic syrup containers from a soft drink maker launched the rain barrel program. “We supplemented the cost of the conversion fixtures and gave away the rain barrels,” says Peek.
Demand soon outstripped supply. “My staff bought wheeled and round trash cans, then created rain barrel models using our $10 conversion kit,” says Peek. “If residents bring in their trash can and buy the kit, we’ll install it.” Master Gardeners showed people how to attach the rain barrels to their houses and educated them on stormwater issues and the management program.
Scientific projects include monthly water chemistry, storm flow, and macroinvertebrate sampling at three watersheds to establish baselines and help develop management plans. “We have 17 urban, suburban and transitional watersheds,” says Peek. “Our goal is to build modeling conditions of the three representative types that we can replicate on other watersheds to avoid such intensive surveys.”
The staff developed a walking tour map highlighting different stormwater practices. An interactive Web page allows visitors to report flooding, illegal dumping, or other stormwater problems anonymously and pinpoint the location on the map. The action creates a work order that is e-mailed to the appropriate person.
Who’s responsible?
Beyond taking care of public infrastructure, ACC Stormwater is about to tackle issues on private property. From the late 1980s to 2004, development added more than 250 residential stormwater ponds. Many lack legal documentation identifying who maintains them. In those cases, the county will have to develop a pond maintenance system or form a new crew within the stormwater department to handle it.
Regular pond inspections reveal some with vegetation overgrowing the dam or primary spillway pipe. Others, filled with sedimentation, no longer function as flood controls. Aging galvanized spillway pipes and joints leak. Some ponds need retrofitting to reflect current engineering and design practices.
“The state is presently okay with us inspecting the ponds, but we want to be ahead of the curve,” says Peek. “We have inventoried all of them and analyzed the situations, and we are developing recommendations to present to our elected officials.”
Three dedicated crews maintain the collection-conveyance system. Each is assigned two zones. They identify and submit work orders for repairs and use two Vactor combination trucks to clean catch basin sumps and remove debris in clogged pipes. One-third of the system is cleaned every year.
A pilot project arose when Peek’s staff asked developers to incorporate more innovative stormwater features. They said the approach didn’t work; The county responded by building demonstration projects. Besides rain gardens, three public buildings have cisterns to reduce potable water use and porous concrete parking lots.
“We explained how pipe size reductions affect development costs, and how stormwater pollution limits our wastewater discharge capacity and ability to grow,” says Peek. “It’s starting to pay off. Some developers are using the techniques.”
Once most residents understood that twofold nature of stormwater projects, they appreciated the department’s accomplishments. Its aggressive approach to nonpoint source issues has ensured Athens-Clarke County’s future development for decades.
