Strategies to reduce environmental impacts

Posted in: Cultural Resources, Environmental, Highways

streamOne common question environmental scientists hear is “What is considered an impact?” The answer is not always as cut-and-dry as it may seem. There are a number of potential environmental impacts to consider while planning a transportation project. The most common of these, and typically the most challenging to navigate, are impacts to wetlands and streams.

The Clean Water Act prohibits impacts to wetlands, streams and other waters of the United States. An impact is any activity regulated by the U.S. Army Corps of Engineers  under the protection of the CWA. Regulated activities can include clearing, culverts and pipes, draining, dredging, flooding, filling, riprap and shading.

There may be times environmental scientists may receive authorization to slightly impact the environment by obtaining a CWA Section 404 permit from the USACE. This process can be time consuming and not always the most attractive option. Environmental scientists should first consider modifying certain activities to minimize impacts to the environment and potentially avoid the need for a Section 404 permit.

If you consider the following aspects during the planning and design stages of your transportation project, you may reduce permitting efforts and shorten the overall project schedule.

Clearing wetlands

Utilize hand clearing (men with chainsaws) rather than heavy machinery to create a clearing. Mechanized clearing is a regulated activity, necessitating a Section 404 permit.

Construction access

In lieu of haul roads or temporary fill, consider timber mats, barge mats or other temporary structures. These options have less impact on the environment and are typically not considered an impact.

Cleaning out fall ditches

Reshaping or channelizing a stream is a regulated activity and therefore considered an impact. However, hand clearing vegetation and removal of debris through non-mechanized methods is less invasive and will most likely not require a Section 404 permit.


Shading from bridges or other structures can affect the amount of sunlight the water receives. This can result in limited plant growth, which may increase scour and sedimentation of downstream waters. The height and width of the structure is likely to be the determining factor for whether this is considered an impact.

Pre-application meetings with your regional USACE office can help you determine whether implementing these methods are prudent and feasible to the success of your project. For more information about these alternative methods or other permitting concerns, feel free to contact me or your local environmental team.

Matt DeWitt

About the Author

Matt DeWitt routinely performs and specializes in natural resource studies, permitting, National Environmental Policy Act compliance, regulatory agency coordination, mitigation and compliance studies. With an emphasis on CWA and NEPA compliance, he is committed to fostering sound wetland science, education and management.

Read more posts by Matt DeWitt

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