News stories over the past year, especially in recent months, have raised questions about how construction projects affect archaeological and historic resources. Which projects must be reviewed? What does the review involve? How long does it take? Could it delay or stop construction?
These five questions and answers explain how construction and archaeology are intertwined.
1. Why are archaeologists involved in modern construction projects in the first place?
Archaeologists were not always involved in construction projects. During the 1960s U.S. construction boom, people realized how much history, heritage, and environment was being lost to development. This public concern was captured in the 1970 song Big Yellow Taxi ("paved paradise and put up a parking lot").
In response, the National Historic Preservation Act of 1966 was signed into law to reduce the destruction of significant sites. It requires the federal government to identify and assess the historical significance of any historic or archaeological site before starting construction that uses federal money, sits on federal land, or requires federal permits.
Common triggers for this law include:
- Federal Funding: FEMA flood improvement dollars, USDA rural utility services, Federal Highway Administration Transportation Alternatives Safewalks to School programs, and more.
- Federal Lands: Federal highways, National Parks, USDA Forest Service property, U.S. Fish and Wildlife Refuges, U.S. Army Corps of Engineers waterways, military installations, federal prisons, and more.
In 1969, Texas passed a state-level version: the Texas Antiquities Code. This provides similar protection before construction can occur on state or local public land (cities, counties, independent school districts, ports, and river authorities). It covers projects like city and county roads, new schools, municipal water lines, park playgrounds, and utilities in public rights-of-way.
Because archaeological sites are usually buried and unseen, archaeologists must review any project crossing public land in Texas, using federal dollars, or requiring federal permits before ground-disturbing work begins.
However, not all investigations find sites, and not all sites are significant. Most projects proceed once the survey is complete because no significant sites will be impacted. Additional research is required only when a site offers new historical information, connects to a significant person or event, or represents a unique architectural style (such as indigenous mounds, Civil War earthworks, or Spanish colonial missions).
2. What does an archaeological or cultural resource assessment look like before construction begins?
Most cultural resource reviews begin with a desktop review of planned construction activities to determine the “area of potential effects” or APE. Defined by the width, length, and depth of anticipated impacts, the APE helps assess risk. For example, a shallow sidewalk in a floodplain carries far less risk of disturbing buried resources than a 20-foot-deep pipe trench.
Archaeologists then evaluate the project area and surrounding radius (usually 1 kilometer or less) using state databases, historic archival, maps, and environmental factors to identify:
- Known Resources: Cemeteries, historic buildings, markers, and previously recorded archaeological sites.
- Environmental Variables: Geology, soil types, topography, and proximity to water. Knolls or ridges near waterways offered safe, elevated sites near food and water. Shallow geologic formations suggest older artifacts have eroded or sit near the surface, while floodplains (alluvial soils) often bury cultural materials deep underground.
- Prior Surveys: Reviewing previous investigations prevents redundant fieldwork.
- Past Ground Disturbance: Existing utility corridors or heavy land clearing can destroy the "context" or integrity of archaeological deposits. Even if artifacts remain, ground disturbance churns them together. For instance, if you take a seven-layer dip cleanly laid out in layers by ingredient type, but then stir it up, you will no longer have neat levels of cheese, salsa, guacamole, and beans. Instead, they will all be mixed together and harder to individually identify.
Thanks to modern online databases, background research is conducted quickly from the office. Archaeologists submit their recommendations (either to clear the project or conduct a physical survey) to the Texas Historical Commission (THC), which acts as the State Historic Preservation Office (SHPO). The THC usually concurs with these findings, clearing most construction projects at this initial stage.
If further work is required, archaeologists perform a physical survey. One type, shovel testing, involves digging a linear or grid pattern of small test holes, typically 40 centimeters (about 16 inches) in diameter and 20 to 80 centimeters (8 to 31 inches) deep, and passing the soil through quarter-inch mesh to recover artifacts.
The other survey is called deep testing or mechanical prospection. In alluvial floodplains or windblown soil deposits where artifacts may lie beyond shovel depth, backhoes dig trenches or extract soil cores for screening.
It remains extremely rare for a project to require investigations beyond this initial survey level.
3. What kinds of sites, artifacts, or cultural resources might archaeologists be looking for?
The most important things archaeologists seek are artifacts and features with “integrity” and temporal or cultural context. Artifacts can include many different things and are portable objects that have been made or modified by humans. Features are non-portable elements such as storage areas, hearths/fireplaces, earth ovens/barbeque pits, structures, or landscape modified or created by humans (irrigation canals, earthen berms, roads, etc.).
Artifacts can be great indicators of how people were living, what type of society they had, how they interacted with their environment, what type of diets, even insight into the type of technology used to create the artifacts. Since the technological needs of people and cultural styles can change over time, artifacts that had a specific style or specialized function are often unique enough they are considered “diagnostic.” Diagnostic artifacts have styles associated with known time periods/cultures. Even if artifacts themselves are not diagnostic, they may be at the same level of dirt and in association with material that can be dated by radiometric means, such as carbon dating (C14), which is the most widely known dating method.
To justify a site as having potential eligibility to be listed on the National Register of Historic Places, archaeologists have to be able to identify and explain the “research value” the site may have. Not every site has the potential to provide new information about the past. For instance, if we have a lot of debris and flakes from making projectile points or other tools, but no actual points, no organic material (bone, botanical remains), and no features (hearths, earth ovens, etc.) then we generally cannot learn much new information about a site. In that case, no further work or investigation is necessary.
Archaeologists also look for what we call “integrity” (or meaning still in its soil layer context with other artifacts in relatively the same position to each other as they were in the past) at a site. Even if we find lots of artifacts, a site may not retain integrity, and no further investigations are warranted.
4. Does an archaeological discovery necessarily stop a construction project, or are there ways preservation and development can coexist?
An archaeological discovery would never stop a construction project from occurring. It is always possible to “mitigate” the potential damage to an archaeological site by investigating the site’s parts that are significant before construction occurs. Sometimes, excavation can seem like the “pricier” alternative due to the smaller scale of the construction project, and in those cases project sponsors may shift the project’s location or realign the location to avoid a site. Even the most premiere archaeological sites in the country, however, could be scientifically excavated by archaeologists, allowing a construction project to continue. In those cases, there may be delays and added costs to a project to conduct these important excavations and ensure that no important historical information is lost.
Sometimes, along with other considerations, projects may be altered, shelved, or abandoned; however, archaeology is never the deciding factor. There is always a balance when considering a project. Regulatory reviewers often consider the scale and need of a project when balancing preservation and development. Oftentimes, people’s voices are heard, and projects are altered or shelved due to public input on these public projects.
Heritage regulations requiring archaeologist involvement on public-associated projects exist so that important information about the past is not lost. The best way to achieve that when construction projects go forward is to make sure the public learns about that novel information and that the information learned is not buried (pun intended) in technical reports.
Spring Lake, for example, is a premiere archaeological site on the Texas State University campus. There, the Center for Archaeological Studies has developed museum displays, robust online information materials about the site, glass-bottom boat tour information for tour guides, participation in Discovery Day public outreach events, and even TxBOX: A Museum in a Box resource free for loan to any K-12 public school to share information about the site with the public. We were also involved in the New Braunfels Utilities’ Headwaters of the Comal project that has resulted in a lot of public outreach and displays for the public. Needed construction and development can occur while allowing the information to be saved and shared.
5. What are some common misconceptions about archaeology's role in construction?
The most common misconception is that an archaeological site can permanently halt construction and kill a project. This is not the case as we can always mitigate even the most significant sites by fully documenting and excavating them, allowing construction to move forward. As archaeologists in Cultural Resource Management/compliance archaeology, we diligently work to balance public need and preservation of the historical information available from archaeological resources by finding ways for projects to move forward. When brought in early to the process, we can maintain compliance with cultural resource and environmental laws while reducing costs, maintaining project schedules, and reducing labor demands across multiple sectors, and help construction projects have positive impacts for local citizens and build positive public rapport.
Often, we can help identify where deposits are and recommend minor realignments that would avoid resources. We only fully excavate the portions of a site that contribute to its eligibility for inclusion on the National Register of Historic Places and cannot be avoided. A related misconception is that every archaeological site causes delays or interrupts construction timelines; however, most archaeological sites we find are not eligible for listing on the National Register of Historic Places and projects proceed as planned.
Closing thoughts
The presence of a historic or archaeological resource would never prevent a construction project from occurring. There are many positive ways to streamline the system with early involvement to avoid issues down the line that may cause delays or temporary halts in active construction.
Cultural resource and archaeological compliance regulations exist to ensure that projects on public land, paid for by public money, or needing permits to protect the public do not destroy important historic and archaeological resources. These regulations also give the public a much-needed voice and power to preserve our heritage. Privately funded projects on private land that do not require federal permits do not have to conduct any archaeological review prior to construction.
There is a way to balance protecting history and information about our shared past as a country while allowing projects for the public good to move forward. Modern cultural resource compliance regulations were designed with that goal in mind.
