Case Studies: Stormwater Management

Case Studies: Stormwater Management

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Level monitors used to measure green infrastructure performance

Problem: It is well established that green infrastructure or nonstructural programs can be effective in reducing stormwater runoff volume and pollution from urban areas. One Tennessee utility put their GI investment to the test by developing a bioretention basin to decrease the volume of stormwater runoff. The utility was concerned with the effects of runoff from a park going into an adjacent stream. 

Solution: Both the runoff volume and potential pollutant loads from pet feces led them to design a system which reduced the runoff volume through measures such as infiltration and evapotranspiration. To measure performance, a stormwater vault upstream from the GI area captured park runoff, which then distributed into an area with selected, high uptake, native plants. Residual runoff from the GI area was captured at a second vault located downstream. ADS ECHO level monitors were installed in both the up and downstream vaults. Data was captured in 15-minute intervals (5-minute intervals during storm events), stored in memory and transmitted daily to cloud-based software. The time series data from the inlet was compared to the outlet to show a reduction in flow, hence lowering the amount of E. Coli going into the receiving stream. 

Result: The utility found that they had a substantial capture rate, confirming the success of the GI implementation. With this type of validation, the utility now has data and corresponding proof to tackle additional areas knowing that they can justify investment. 877-237-9585; 

Rake helps fish hatchery maintain optimal conditions

Problem: Built in 1974, the Jim Hinkle Spring River State Fish Hatchery is on a 7-acre island in the Spring River near Mammoth Spring, Arkansas. Water for the six tanks in the gravity-fed hatchery comes from the Spring River near the Spring River Dam at a rate of about 70,000 gpm. The freshwater intake at this facility has a high volume of weeds, stringy material and vegetation that jeopardizes the water volume for the downstream fish hatchery production.

Solution: In 2023, the hatchery installed two Duperon Harvest Rake screens to replace the older generation manual screens. The rakes collect debris upstream from the hatchery and deposit it on a conveyor belt, reentering the river downstream. This process allows the hatchery to remain debris-free while minimizing impact on the natural debris flow of the river. 

Result: As an automated system, the Harvest Rake is reducing labor requirements for the hatchery. The setup includes speed control that can be adjusted for large debris and above average flow conditions, such as after a large rain event. A rear spray bar ensures the conveyer is always clear and ready to accept debris from the rake. The rake met all environmental compliance requirements. 800-383-8479;

Catch basin risers used for highway resurfacing project 

Problem: In the section being resurfaced on Wisconsin’s I-39 highway, about a hundred catch basins laid atypically close to a concrete barrier wall. “In places, the barrier wall was actually over the basins,” explains Curt Neuhauser, project manager for the Wisconsin DOT. “This initially seemed like it might cause a lot of unexpected work and expense. Fortunately, the contractor floated an option that sounded like it would work.”

Solution: Catch Basin Risers from American Highway Products were used to raise inlets without removing any surrounding asphalt. “I’ve used them before, and have found them quick and easy to install,” says Payne & Dolan Project Manager Sam Bilhorn. “I felt they could be used here, and we could avoid removing or undermining the wall. And it wasn’t even a change order — the point was, we were able to avoid a change order. And WISDOT agreed they were worth a try.” The risers are precisely sized as needed for given situations; width, depth and height are customized for particular jobs. The manufacturer will even provide multiple sizes per order, and keep them organized by size when shipping.

Result: “We used about 100 on the I-39 project, and had no problems at all,” Neuhauser says. “All we had to do was remove the grate and install the risers. We didn’t have to remove the barrier wall, and we didn’t even have to dig out any roadway. The proof is in the pudding, of course, but we like how they worked on this project, and we’ll be using them again.” 888-272-2397;

Manufacturer solves streetsweeper stormwater grate cover challenge

Problem: Two of the nation’s largest home building firms expressed frustration about a common site development National Pollutant Discharge Elimination System challenge. Street sweepers keeping development roads clear of debris from empty lots during construction tend to tear up traditional overgrate filters made of non-woven geotextiles. Traditional under-grate options require special tooling or multiple personnel to lift heavy grate covers to affix and maintain both over and under-grate options.  

Solution: GEI Works developed a patented overgrate option that allows customers to affix the grate cover to the grate without special tooling, or having to lift the grate. Specialized fasteners provide both above and below-the-grate access without having to lift the grate itself. The over-grate filters are made with street-sweeper friendly materials that significantly reduce wear on the filter itself, extend use life and reduce labor costs to maintain. Additionally, options are available with larger aperture windows to allow more water flow and visibility over the grate, to reduce ponding. 

Result: Large new-development Stormwater Pollution Prevention Plans utilizing the overgrate filters remained compliant and reduced maintenance costs. Investing in a longer-term overgrate filter despite initial cost difference to widely used typical filters lowered project costs overall through longer duration between replacements, minimal installation time, no special tooling requirements and easy maintenance. 772-646-0597;

Manhole cutter cuts labor time on sewer system restoration

Problem: Years ago, Ames, Iowa initiated a large-scale restoration of its sanitary sewer system. Manhole lids need periodic adjustments to keep them level with the road. Previously, manhole repairs involved costly, labor-intensive methods that produced mediocre outcomes. 

Solution: To expedite and economize the process, the city adopted the Mr. Manhole cutter and chimney rebuild system. This method uses round cuts, generating 20% less waste and using 20% less material than the traditional square cuts. Eric Cowles, a civil engineer in Ames, vouched for the speed and efficiency of the technology, noting that it eliminated much of the anticipated resident grievances. The Mr. Manhole system cuts repair time down to an hour, slashing costs and labor. It also ensures worker safety and minimizes traffic disturbances, ensuring resident satisfaction. 

Result: With this system, Ames transformed its repair approach. The project, estimated at $1.9 to $2 million, was completed at $1.6 million in under a year, surpassing quality expectations. 833-242-2221;

Noncontact level measurement saves plant time and money

Problem: At the Fourche Creek Treatment Plant in Arkansas, more than 7 mgd is collected, treated, and disposed of as reclaimed water that exceeds water quality standards before being released into the Arkansas River. The plant uses automatic bar screens at their facility for efficiency and ease, and therefore level measurement is critical in monitoring this process and alerting staff to potential overflows. A previously installed radar level transducer failed with no notice. 

Solution: Plant operations chose to replace their existing products with cost-effective Pulsar Measurement REFLECT devices. The two-wire radar level sensor provides confidence in level measurement in challenging conditions such as turbulent applications with foam present, making it a suitable choice for wastewater pretreatment stages. It is noncontact and thus requires no routine servicing, and its robustness maintains accuracy with moisture, debris and chemicals present.

Result: Fourche Creek saved both time and money, allowing them to protect public health and the environment even more effectively. 888-473-9546;


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