Case Study: Bolton & Menk

Bolton & Menk Cuts Project Time on Citywide Stormwater Management Plan

About Bolton & Menk

Bolton & Menk, an engineering firm based in Mankato, Minnesota, often provides engineering services to Minnesota municipalities. But most projects focus on narrow subsets of a city’s water management, such as a water distribution center, treatment plant or watershed stormwater master plan.

When the City of Ramsey (a suburb northwest of Minneapolis, MN) turned to Bolton & Menk, it needed a stormwater management plan for the entire municipality. Consisting of about 30 square miles, the relatively flat terrain includes wetlands, ponds, streams, storm sewer systems and drainage ditch systems.

Since 2002, Ramsey has been designated a mandatory US EPA NPDES Municipal Separate Storm Sewer System (MS4) community. Therefore, the city’s plan had to take into consideration federal requirements by the EPA, as well as requirements from the state and a seven-county Metropolitan Council. At the same time, the city’s own goal was to control or eliminate stormwater pollution.

The City of Ramsey was initially built without storm sewer systems to handle anything greater than a 5-year storm event. Bolton & Menk’s approach included separating the city into multiple watersheds and modeling each watershed simultaneously. The ultimate goal was to accommodate the 100-year storm event after the city is fully developed without creating adverse downstream conditions.

“Most storm sewer networks in Minnesota are undersized relative to the storms that are coming now,” said William Douglass, P.E., Water Resources Manager at Bolton & Menk. “Most were designed with no consideration for 100-year flooding.”

Considering the scope of the project, the firm sought a more powerful, integrated stormwater modeling program. At the time, it used a combination of two or three different applications. However, operating separate programs meant lost time going back and forth between applications. If they changed one aspect in one program, they had to change connecting elements in other programs manually. For the Ramsey project in particular, it was difficult to model major open ditch systems accurately in relation to the rest of the city.

“We had to use one program for ponds and culverts and another for a pipe network and storm sewers,” Douglass said. “We had to go back and forth between modeling the storm sewers and hydraulic gradelines. It was a pain to use two different programs with different results, and neither could send anything to GIS.”

Pipes and Ponds in One Application

Considering the Ramsey project, and other upcoming citywide projects, Bolton & Menk needed more integrated modeling. Douglass attended a three-day, hands-on workshop for one particular stormwater software application. When the instructor’s example project returned 26 error statements before it could run, Douglass knew the software lacked the ease of use the team sought.

The ability to model with various hydrology methods was also high on the list of requirements. For the Ramsey project, the firm needed to use EPA’s Storm Water Management Model (SWMM). On other Minnesota projects, the team most often uses the Soil Conservation Service (SCS) TR-20 hydrology method.

StormNET by BOSS International proved to be the most flexible and capable application the team evaluated. The fully-dynamic hydrology and hydraulic model analyzes both simple and complex stormwater systems using a variety of methods and models, including water quality. The software includes a variety of hydrology methods, allowing Bolton & Menk to use the right method for each project.

“StormNET is much more user friendly and powerful than other programs out there,” Douglass said. “It has the flexibility in handling pipe and ditch networks everywhere, as well as analyzing ponds and wetlands right along with it.”

“The fact that StormNET works similarly to EPA SWMM gave it that much more validation as well,” added Tim Olson, Design Engineer and Modeler. “It reminds me a lot of EPA SWMM, so it was an easy transition for myself and to teach to others.”

Seamless Transfer into ArcGIS

To collaborate more effectively with City of Ramsey engineers, the firm also acquired a StormNET license for the City of Ramsey Engineering Department. The two teams worked closely on the citywide project, which required more than 5,000 nodes in StormNET.

They modeled both the 10- and 100-year storm events and devised a color-coded analysis of ponds: green ponds were functioning adequately, yellow ponds were using the emergency overflow and red ponds were potential threats to structures.

The ability to model a complex stormwater model directly brought significant efficiency to the large project. Engineers can model storm sewer systems along with pond systems. If they change one element, all related elements automatically adjust accordingly—instead of having to make those changes manually in another program. “It’s the one-stop shop; that is what it comes down to,” Douglass said.

To start, Bolton & Menk brought background CAD drawings into StormNET from AutoCAD^®. When they completed a phase, they exported shapefiles from StormNET directly into ArcGIS^® for graphical presentation to the rest of the team and the city.

“The transfer of files is seamless,” Olson said. “We can take seven complex models of the city and output that graphically. All the figures generated in StormNET go right into GIS.”

StormNET also facilitated true collaboration between Bolton & Menk and the city on what was the largest engineering project the city has undergone in many years. The firm emailed files to Leonard Linton, the main city modeling engineer. This allowed Linton to run and validate models, and if he made updates, he could email the file back to Bolton & Menk so they had the latest iterations.

Linton had tried other stormwater software applications prior to the project. Compared to those, StormNET allowed him to generate and run models more quickly and without error.

Bolton & Menk also appreciated the technical support provided by BOSS International’s engineers to ensure the project went as smoothly as possible. “We couldn’t ask for a better working relationship with the people at BOSS,” Douglass said.