Sometimes a project or undertaking has the potential to cause an adverse effect on a historic property, whether it is a historic house, a bridge, a cultural landscape, or an archaeological site. When AECOM is involved in consultation with a State Historic Preservation Office, we make best efforts with our clients to avoid or minimize effects on historic properties. If in the end, if this is not possible, AECOM can provide consultation for mitigation measures for adverse effects.

AECOM has experience in the drafting and execution of Memorandums of Agreement (MOA's). These documents outline the need for the mitigation and the measures that will be taken to complete it. For aboveground resources, mitigation measures often take the form of Historic American Building Surveys (HABS) and Historic American Engineering Record surveys (HAER). Photography and public signage are other mitigation possibilities. For mitigation of archaeological sites, Phase III Archaeological Data Recovery excavations are large-scale excavations designed to recover the data a site contains before a project proceeds and the site is lost. Additionally, AECOM designs alternative mitigation measures such as walking tours and high school lesson plans. AECOM feels that these types of products can have a more wide-reaching and educational impact on the public.