Utility Partners With Customers to Protect Floridan Aquifer

Oct. 18, 2018
Technology taps nature to yield innovative, low-cost solutions.
FLORIDA, NOV 5, 2018 -- Floridians love the great outdoors and the activities that abundant, clean water supports. Increasingly, however, nutrient loading and groundwater withdrawals are jeopardizing natural sources of clean water. For over 20 years, Gainesville Regional Utilities (GRU), Florida’s most comprehensive utility, has been helping to mitigate this problem by partnering with customers to construct manmade wetlands. GRU uses reclaimed water to hydrate these constructed wetlands, which are built on naturally dry, sandy land. The wetlands naturally filter the reclaimed water, reducing nutrients to low levels while simultaneously recharging the Floridan aquifer. Local organizations provide the sites for these wetlands, and GRU handles operation and maintenance. On the rare occasion when problems arise, GRU seeks out high-tech partners who share their commitment to innovative, economical problem solving.

Project Background and Development
The Kanapaha Middle School (KMS) is home to two of these wetlands: the KMS Reclaimed Water Feature and the KMS Hybrid Aquifer Recharge Wetland. The first site, the KMS Reclaimed Water Feature, was constructed in the mid-1990s to demonstrate that water reclamation features can beautify landscapes. Since then, the site has been used to test the effectiveness of groundwater-recharge wetlands at reducing the nitrogen content in reclaimed water. The site is now a prized teaching tool for the middle school.

The design of the KMS Reclaimed Water Feature is simple. It begins with a manmade waterfall near the school’s entrance. Reclaimed water is piped to the top of the waterfall, where it descends into the first wetland pond. Gravity guides the water through a series of ponds populated by various wetland plants. Much of the water seeps into the ground as it passes through the system on its way to the last pond.

The second site, the KMS Hybrid Aquifer Recharge Wetland, was created in 2016 when an existing dry stormwater pond was repurposed as a wetland. This single basin combines stormwater and reclaimed water into a system that reduces nutrients and recharges the aquifer. Every day, this stormwater basin naturally and economically replenishes the Floridan aquifer with approximately 600,000 gallons of high-quality water, surpassing conventional rapid-infiltration basins in nutrient reduction.
Wetland System Operation

To provide optimal conditions for wetland plants, the water level in the basins should be maintained at an average depth of 12 to 18 inches. Each KMS system has a sensor that communicates the wetland’s water level to a pump controller, which then operates a valve to start or stop the flow of water into the system. The pump controller communicates via radio with GRU’s SCADA system, which is used to monitor and control the water levels.

The water-level sensor of the Reclaimed Water Feature is located in the last basin. The valve at the beginning of the system is opened and closed remotely to regulate the flow of water into the system. A single sensor and pump controller communicate with the SCADA system to regulate the water level. When the water level in the last basin falls to its minimum, the valve opens to add more water. Much of the water infiltrates the ground during its journey to the last pond. Once the water in the last pond reaches the maximum level, the valve at the beginning of the system closes. The water level of the single basin of the KMS Hybrid Aquifer Recharge Wetland is maintained the same way.

Addressing Opportunities for Improvement
These manmade wetlands thrive without much attention, but when problems arise, GRU steps in. KMS recently lost automated control of its water levels when its pump controller stopped communicating with GRU’s SCADA system.

GRU identified two options. It could hire an integrator to evaluate the problem onsite, which would be expensive, or it could try a new pump controller. One of GRU’s trusted vendors, VTScada, suggested Schweitzer Engineering Laboratories (SEL), a company well-known in North America for its innovations in the electric power industry. When GRU learned that SEL makes pump controllers, they wanted to learn more.

Ultimately, GRU needed only one device to solve their problem. Preconfigured to be SCADA ready, the SEL-2411P Pump Automation Controller easily integrated into the KMS wetland systems. The device was affordable and worked well with GRU’s existing radios and equipment.

While the SEL pump automation controller excels at liquid level pump-up and pump-down applications, such as those found at reservoirs and lift stations, it is also ideal for infiltration wetland systems like the ones at KMS. An SEL technical support engineer customized the pump controller program for the KMS wetlands and personally delivered the equipment.

System Setup
GRU needed to specify when the wetlands would receive reclaimed water to guarantee that their operations personnel would be available to handle any issues, such as sinkholes or demand changes. Also, because reclaimed water customers in Florida irrigate in the early mornings, GRU wanted to ensure that it could meet this competing demand. The SEL-2411P controller’s “time of day” control scheme lets GRU decide what time the controller will operate. SEL helped GRU install a demonstration unit and, in only one day, the new controller was ready to operate.

“We don’t get any calls on it at all,” said Tim Pilcher, the SEL regional sales manager who helped GRU set up their system. “It’s just sitting there rocking along. They know how to operate it. They know how to set it up.”

GRU takes its responsibility as a steward of Florida’s environment very seriously and likes collaborating with those who also know the value of solving problems quickly and economically.

“SEL was on the ball,” said GRU Instrument Control and Electrical Technician Marcus Mitchell. “They have several qualified service [personnel] and technical support a call away.”

Mitchell also liked SEL’s ten-year warranty, which the company typically honors beyond ten years to cover the full lifetime of its products.

Lasting Benefits
Simple, manmade wetlands, such as the ones at KMS, are easy to construct and can be operated with just a few pieces of specialized equipment. And, because these aquifer recharge wetlands require little upkeep, they have the added advantage of lowering maintenance costs. As the population of Florida grows, the aquifer will continue to face challenges. For GRU, addressing these challenges with cost-effective, state-of-the-art technology that works reliably with environmentally responsible solutions is especially valuable.