Case Study: 4Site, Inc.

4Site Improves Accuracy, Reduces Engineering Time with StormNET’s Water Quality Capabilities

Background Information

In 1983, most people had never heard the term, “new urbanism.” But 4Site, Inc. of Huntsville, AL was actively practicing this progressive approach in its land planning and design.

More than 25 years later, the firm has built a reputation for designing more livable communities in Alabama, Georgia, Tennessee and even New Mexico. With an emphasis on environmental, social and economic sustainability, the 4Site firm lives by the mission, “Envisioning Tomorrow’s Legacy Today.”

On a LEED (Leadership in Energy and Environmental Design) commercial development project in Madison, Alabama, 4Site had the opportunity to implement stormwater rain gardens into the project. The LEED for Core and Shell-certified project includes two office buildings comprising of about 85,000 square feet.

At the time, engineers used a largely manual approach to modeling stormwater projects, applying the Rational Method and HEC-1 by hand. They defined projects in AutoCAD Civil 3D, and then went back and forth between Civil 3D and a series of manual calculations to arrive at the correct pipe sizes.

“What we had in-house did not effectively address low-impact development (LID) or sustainable design,” said Jerry Cargile, P.E., Principal Partner. “It really hampered productivity, especially with projects as complicated as residential stormwater networks. We needed a modeling program that could handle sustainable design, and work well with Civil 3D.”

Water Quality Modeling with StormNET

4Site researched available LID modeling options before selecting StormNET by BOSS International. The fully-dynamic hydrology and hydraulic model analyzes both simple and complex stormwater systems using a variety of methods and models, including water quality. StormNET enables engineers to perform urban stormwater water quality modeling using rain gardens, green roofs, retention ponds, wetlands and more.

“StormNET has the broadest capabilities and integrates easily with Civil 3D. We wanted to have all the tools we could and felt like StormNET is a leading edge piece of software,” Cargile said. “StormNET can handle any situation we could encounter.”

StormNET consolidates all stormwater modeling into a single application. Engineers export pipe networks from Civil 3D easily into StormNET. There, they can evaluate hydraulic grade lines, and adjust pipe sizes accordingly. Then, with a single-step, the completed design is back in Civil 3D.

StormNET lets us model the entire project as a whole instead of parts.

Jakie Whitaker
Project Manager
4Site, Inc.

Modeling the Entire Project – One Application

For the LEED commercial rain gardens project, 4Site were able to specify the soil types of the underlying infiltration layer to better manage runoff and infiltration, rather than develop a conventional storage detention pond along with a typical outflow structure containing orifices and weirs. Jackie Whitaker, Project Manager, used EPA-SWMM along with HEC-1 in StormNET.

With the advanced detention storage modeling capabilities in StormNET, Whitaker specified infiltration rates based on the types of soil 4Site planned to use in the rain gardens to control discharge rates. At the same time, he could adjust stormwater pipe sizes directly in the model. With each change, he could run the model to determine the impact of various storm events, and then make adjustments in real-time.

“StormNET lets us model the entire project as a whole instead of parts,” Whitaker said. “It handles flow calculations, hydraulic grade lines and lets us update pipe sizes—all within the software. We can do it all right within StormNET in a single step instead of going through 2-3 long sets of calculations by hand.”

From there, Whitaker brings the design back into Civil 3D or exports it into Excel. That allows 4Site to explain designs to clients more easily. “We can show the client the output results as AutoCAD drawings, graphical plots and spreadsheet reports so they can better understand what’s happening,” Whitaker said.

Greater Design Accuracy

Modeling in one application, without manual calculations and with tight Civil 3D integration, reduces errors and enhances design accuracy. With StormNET, 4Site also quickly transitioned to using EPA-SWMM, making for more accurate modeling for low-impact development, Whitaker said.

To that end, he notes that they determined that they were actually getting higher stormwater runoff flow rates—about 10-15 percent more—than what they had computed in the past. That allowed 4Site to more precisely design the rain gardens to accommodate runoff.“With previous modeling methods, we were losing flow,” Whitaker said. “We see higher flows in StormNET because the software is more detailed.”

Precise Designs – Faster

4Site also reduced the amount of time required to model the rain gardens by using StormNET. The software eliminates the need to switch back and forth between modeling and manual calculations, as well as enter data into AutoCAD.

“With this LEED rain garden project, we saved at least a day’s worth of time using StormNET,” Whitaker said. “We have more time left over to look at designs and pull them together into the complete package to send out.”

Ultimately, this increased efficiency and flexibility increases productivity and client satisfaction. “StormNET allows us to be more efficient in our modeling,” Cargile said. “It’s a seamless transition from model to final construction plan sets and documents. It’s also a lot more friendlier in getting the data out to prove designs and meet the requirements of local governing agencies.”