Cultural Resources and Section 106: What Data Center Developers Need to Know

Section 106 of the National Historic Preservation Act (NHPA) requires federal agencies to take into account the effects of their undertakings on historic properties and to give the Advisory Council on Historic Preservation (ACHP) a reasonable opportunity to comment. It is a process requirement. It does not require that every historic property be preserved, but it does require identification, consultation and a good-faith effort to avoid, minimize or mitigate adverse effects.

An undertaking is a project, activity or program that a federal agency carries out, funds, or permits. For a data center, the federal agency is usually not the developer’s customer or regulator in any other sense. It is the agency issuing a permit or approval that the project happens to need.

Most private data center projects on private land have no federal role in the land use approval itself. Section 106 comes in through a related federal action, most often:

• A Clean Water Act Section 404 permit from the U.S. Army Corps of Engineers for wetland or stream impacts.
• Federal funding or loans, including for related utility infrastructure.
• Use of federal land or a federal right-of-way.
• Federal licensing or approval of related infrastructure, such as some pipelines, power facilities or communications structures.

The same federal nexus often brings NEPA review and Endangered Species Act consultation. That is why the decision to avoid or accept wetland impacts, covered in wetlands and data center development, has effects well beyond the wetlands themselves. Note that the Corps’ review may focus on the permit area, but the area considered for cultural resources can extend beyond it, depending on the agency’s procedures and the scope of its control.

The area of potential effects can include more than ground disturbance. Large buildings, substations and transmission lines can have visual effects on historic properties some distance away, such as a historic farmstead, district or battlefield. Archaeological sites, by contrast, are usually affected only where the ground is disturbed.

Historic properties are those listed in or eligible for the National Register of Historic Places. Eligibility is often the open question, because many archaeological sites and older structures have never been evaluated.

Every state has a State Historic Preservation Officer (SHPO) who consults on Section 106 reviews and maintains records of known sites and surveys. On tribal lands, a Tribal Historic Preservation Officer (THPO) may take on the SHPO’s role.

Federal agencies must also consult with federally recognized tribes that attach religious and cultural significance to historic properties that may be affected, even when the project is not on tribal land. A tribe’s area of interest can cover regions far from its current reservation. This consultation is government to government between the agency and the tribe; the developer supports it with information and is often asked to meet.

Without a federal nexus, Section 106 does not apply. That does not mean cultural resources are irrelevant. Several kinds of state and local rules can still reach a project:

• Unmarked burial and human remains laws, which commonly require work to stop and authorities to be notified if remains are found, regardless of land ownership or permits.
• Cemetery protection laws covering known family or historic cemeteries, which may restrict disturbance and access.
• State environmental review statutes in some states, which can require cultural resource review for state-permitted projects.
• State historic preservation review for projects on state land or using state funding.
• Local historic districts, landmark designations or zoning conditions that address historic resources.

These rules vary widely by state, so confirm them with the SHPO or a cultural resources consultant. Small family cemeteries are especially common on rural tracts and are easy to miss on maps.

Cultural resource work usually starts with a desktop review: SHPO site files, previous surveys, historic maps and aerial imagery, and landform analysis to estimate where sites are likely. The SHPO site files are often restricted to qualified professionals to protect site locations.

If a field survey is needed, archaeologists walk the site and dig shovel tests on a grid, with tighter spacing in high-probability areas such as terraces near streams. Sites that might be eligible for the National Register may need further testing to evaluate them. Field seasons, ground conditions and vegetation can limit when this work is practical.

Findings typically lead to one of three outcomes: no historic properties affected, avoidance through layout changes such as setting aside a small preserve, or mitigation such as data recovery excavation. Avoidance is usually faster and cheaper. Even with a clean survey, construction plans commonly include an inadvertent discovery plan for unexpected finds.

1. 01Identify whether any federal nexus is likely, starting with wetlands, federal funding and federal land.
2. 02Have a qualified consultant review SHPO site files and previous surveys for the site and corridors.
3. 03Check historic maps and imagery for cemeteries, homesteads and old structures.
4. 04Note historic properties nearby that could be visually affected by tall buildings or transmission.
5. 05Scope any field survey early enough to fit within the diligence period.
6. 06Keep sensitive areas out of the core building footprint where possible.

Cultural resources sit alongside species, wetlands and floodplain in the environmental part of the site due diligence checklist, and they belong in the broader permitting plan.