Challenge: During the course of the environmental process and preliminary design, impacts to wetlands and streams within the project area exceeded the mitigation threshold of 0.1 acre/300 linear feet. The project had required off-site mitigation and a monitoring period of 10 years, which would have cost the client a budgeted amount of $80,000.

Solution: Through detailed investigation and extensive design modifications, RQAW | DCCM brought the impacts of wetlands and streams that were not currently encapsulated under the 0.1 acre/300 linear feet mitigation threshold. The extensive design modifications reduced the structure lengths to the minimum required for the widened roadway, steepened the side slopes and added guardrail where necessary, eliminating roadside ditches in the areas where wetlands were present, and added wing walls where necessary to accommodate the shorter structures. Extensive coordination with the regulatory agencies (IDEM and the USACE) enabled us to accommodate on-site mitigation opportunities via native vegetation plantings along the relocated streams and wetland areas within the right-of-way limits and only one year of monitoring to ensure the vegetation is growing properly. This allowed the project to stay on budget and on schedule while saving the client $80,000 in mitigation costs.