AE services meeting the definition of AE Services as defined in 40 U.S.C. 1101 and FAR 2.101 are required to support the Mobile District ER Program. Timely and cost-effective responses are required to support the program. AE services will be performed primarily within Mobile District's Area of Responsibility (AOR) in the southeastern United States to include Central and South America, Puerto Rico, the U.S. Virgin Islands. AE services may also be used to support the ER Program outside of Mobile District's AOR, given a need by another USACE Division or stakeholder execution requirement upon satisfaction of proper coordination and approvals. The services provided will include a full range of comprehensive support environmental services focused on complex Hazardous, Toxic, and Radioactive Waste (HTRW) projects to include strategy development, plans, data gathering, analysis, evaluations, studies, designs, remedial design, and regulatory support specific to the Environmental Restoration Program. The services will include analyzing and evaluating environmental regulations for implementing studies, designs, and program initiative; providing comprehensive programmatic support of policies, guidance and regulations for various stakeholders and agencies; Hazardous, Toxic, and Radioactive Waste (HTRW) investigations and studies; HTRW remedial design; HTRW feasibility study, proposed plan, public meeting, and record of decision ; HTRW vapor intrusion investigation and/or vapor intrusion remedial design; HTRW pilot study and/or bench study hazardous, toxic and radioactive material/waste site investigations/assessments; treatability studies; pilot studies; risk assessments; sampling and analyses; data validation; electronic data management; geotechnical investigations; monitoring well installation; groundwater modeling; groundwater and surface water quality assessments; water reuse initiatives; vapor intrusion monitoring, assessment and modeling; environmental site assessments; surveys/inspections for asbestos, leaded paint, and other HTRW materials; and investigation/study/assessment of emerging contaminants such as per and polyfluoroalkyl substances (PFAS).