Case Study: Roche Ltd. Consulting Group

RiverNET Models Complex River Project 15 Times Faster than US Army Corps HEC-RAS

Background Information

In Quebec, Canada, Route 73/175 is a major north/south highway on both sides of the St. Lawrence River. The two-lane highway links the province with the picturesque, mountainous Saguenay-Lac-Saint-Jean region.

In a $5.8 million project, the Transportation Ministry of Quebec is currently widening Highway 73/175 to improve safety for travelers, and enhance the flow of traffic and goods between Quebec City and Saguenay-Lac-Saint-Jean.

Quebec-based Roche Ltd. Consulting Group is one of the engineering firms working on plans for the widening, which will complete in the summer of 2009. The engineering and construction company designs and manages projects throughout Canada and in more than 50 countries.

Roche’s engineering work on the highway project focuses on a three-kilometer section, which requires a 700-meter diversion of the Taché River near the Jacques-Cartier Provincial Park. Roche must design the diversion in such a way that it protects the area’s wildlife
habitat — beavers, fish, frogs, moose and birds — and present plans for approval to environmental organizations that represent each of those species, and to the Quebec Ministry of Transportation.

Rapid HEC-RAS Model Changes

When the project began, Roche used the US Army Corps of Engineers HEC-RAS software. Roche’s engineers manually entered data into HEC-RAS from AutoCAD drawings and then drew computed HEC-RAS results back on the AutoCAD drawings. With 150 HEC-RAS
cross-sections, complex bends, a bridge, and floodplain mapping, the work had already taken about a month and a half.

“The geometry of this project was too complex to easily model with the US Army Corps of Engineers HEC-RAS,” said Marc Labelle, Specialist Engineer for Roche.

Previously, Roche had used BOSS International ’s StromPack stormwater software with great success. For that reason, the firm decided to try out RiverNET from BOSS International for its compatibility with and similarity to StromPack. RiverNET automates HEC-RAS and HEC-2 within AutoCAD, as well as with its own AutoCAD/MicroStation compatible stand-alone CAD platform.

Once the firm brought in RiverNET, the engineers immediately started using the software on the on-going St. Lawrence River diversion project.

In the project, Roche had to protect existing wildlife, such as creating a place where moose can pass under the bridge and where beavers can make dams in the floodplain. As Labelle presented plans to each environmental organization, he had to integrate their feedback into the HEC-RAS model - requiring repeated revisions. With RiverNET, these changes were quickly integrated into the AutoCAD drawings and corresponding HEC-RAS model.

“We changed and revised the HEC-RAS model about 10 times until everyone was happy with it,” Labelle said. “With RiverNET we were able to instantly re-cut HEC-RAS cross-sections, quickly change the diversion realignment and still incorporate the bridge structure and floodplain mapping.”

3 Days Instead of 45 Days

Labelle found RiverNET more efficient and accurate than the US Army Corps of Engineers HEC-RAS software after comparing models for the same river diversion.

“In RiverNET, we did in three days what took one and a half months to do with HEC-RAS,” Labelle said. “We could build the HEC-RAS geometry more easily in less time. RiverNET showed results matching that of the original HEC-RAS model, but RiverNET was more accurate since it was working directly from the digital terrain model in AutoCAD.”

Labelle only wishes he had used RiverNET earlier in the project. He estimates that with RiverNET the entire project would have taken only eight months, instead of a year-and-a-half using HEC-RAS.

With RiverNET we were able to instantly re-cut HEC-RAS cross-sections, quickly change the diversion realignment and still incorporate the bridge structure and floodplain mapping.

Marc Labelle
Specialist Engineer
Roche Ltd. Consulting Group

Impressing the Client

In addition to faster projects and enhanced accuracy, Labelle finds RiverNET easier to demonstrate results to others in the firm and to clients. Depending on the audience — whether they are other engineers, environmental groups, or government agency reviewers — he can present designs in a way that audiences can understand. That capability was critical as he met with each environmental organization representing the various wildlife species affected by the St. Lawrence River diversion.

“RiverNET gives us the flexibility to demonstrate modeling results for lots of different people. We can show a complex model with complex results or a simple model with simple results,” he said.

Last year, still early in the highway planning project, he presented the HEC-RAS model to about 20 people involved in the project — highlighting RiverNET’s relative speed. In fact, Roche was the first firm to demonstrate the power of RiverNET software to the Transportation Ministry of Quebec.

“Everyone was very impressed with the precision of the HEC-RAS model,” Labelle said. “Everyone accepted that the RiverNET model was better than the US Army Corps of Engineers HEC-RAS model that had been developed at the start of the project. Client satisfaction was much higher because they are able to see model complexities more easily and quickly.”