Design vs. Construction: Comparing Stream Restoration Costs

Design and consulting costs can be a significant percentage of the overall cost of civil and environmental engineering projects. For stream restoration projects, this can be even more true. A new paper compares the costs of design versus construction for three different stream restoration projects.

F. X. Browne, Inc. Engineering Associate Megan LeBoon presented the paper, "Comparing the Costs of Three Stream Restoration Projects Constructed on Mill Creek between 2004 and 2007 in Lower Merion Township, Pennsylvania," at the 2007 Pennsylvania Stormwater Management Symposium at Villanova University. Three stream restoration projects were designed, permitted, and constructed by F. X. Browne, Inc. on private properties along the Mill Creek near Gladwyne, PA over a three year period. The projects were completed separately on individual residential properties along the creek  in order to repair damage from flooding that caused severe bank erosion and destabilization. They addressed a wide variety of infrastructure and stream stability problems, with a range of bank stabilization and natural channel design techniques. Engineering and design services for these projects included surveying, hydraulic modeling, restoration design, permitting, construction observation, and project management. The study compared design and construction costs for the three projects and analyzed the differences in costs between the projects. 

The study found that, when compared to the overall construction costs, the costs associated with consulting services were higher for streambank stabilization projects than for typical civil engineering projects. This is due to the iterative nature of the design development and the complexity of the permitting process. Some services, such as restoration design, can be normalized per linear foot of stream, while others, such as permitting, depend more upon the complexity of the project and are relatively independent of the size of the project. The analysis also highlighted the benefit of past experience with the same stream, as subsequent projects had lower permitting costs due to the familiarity with the watershed and knowledge of the local permitting processes.

To read the entire paper, click here.