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Flood and Fire: Red River Valley Data Recovery

By Rhiannon Jones, Principal Investigator at Commonwealth Heritage Group, Inc.

The Red River Valley in northeastern North Dakota, northwestern Minnesota, and southern Manitoba is possibly the flattest place you will ever see. As un undergrad, I took a class on Mesopotamian archaeology and my professor explained the flatness of the Tigris-Euphrates region in present-day Iraq by recalling a visit to a zoo in New Orleans. There, he said, he saw a mound of earth with a plaque next to it stating the mound had been created by the Works Progress Administration to give the children of New Orleans a chance to experience what a hill is like. In his opinion, the people of ancient Mesopotamia needed a “hill experience” as well.

Figure 1 – The Red River Valley: this needs a hill experience.

In addition to the lack of hill experiences, the flatness of the Red River Valley means that when the river rises over its banks, the water just goes everywhere. Flooding is a persistent problem, with particularly serious recent floods occurring in 1997 and 2009. As a result, the U. S. Army Corps of Engineers, the Metro Flood Diversion Authority, the City of Fargo, North Dakota, and the City of Moorhead, Minnesota, propose to undertake the Fargo-Moorhead Metro Flood Risk Management Project (Project). The Project will construct a diversion channel around the west side of the Fargo-Moorhead area, similar to the Red River Floodway around Winnipeg, Manitoba, which was constructed in the 1960s. The initial archaeological survey and Phase II site evaluations for the Project had been conducted by other firms in 2011–2013. It was concluded that two sites would require mitigation, as they appeared informative (thus perhaps eligible for the National Register of Historic Places under Criterion D) but could not be entirely avoided by the Project.

Commonwealth Heritage Group, Inc. (Commonwealth) undertook data recovery at the two sites, located near the Maple and Sheyenne rivers, in the autumn of 2019. This was preceded by site delineation and geophysical testing over the summer, aided by Strata Morph Geoexploration, Inc. (Strata Morph) of Sun Prairie, Wisconsin. To examine the landforms and stratigraphic history of the site, Strata Morph dug trenches with a tracked excavator to expose the soil profile, while Commonwealth documented surface artifacts and watched for cultural features to appear in the trenches. During the 2012 Phase II evaluations at the site near the Sheyenne River, an intact hearth feature had been encountered on a buried surface (a buried A horizon) 50 centimeters (1.6 feet) below the modern surface at the site near the Sheyenne River. The feature was a tidy basin of ash atop reddish thermally altered soil. (I supervised that excavation and I always talk about that feature when people ask me about interesting things I’ve found. Usually, they’re disappointed that I’m telling them about a campfire in North Dakota.) Although the location of this feature was now outside of the Project area, we hoped to find something similarly interesting. As time went on, it became apparent that there may not be much to find at either site, other than an artifact scatter on the surface of the plowed farm fields. While it is nice to know that nothing of historical value is likely to be destroyed by a project, it makes for a boring excavation when little is found.  

Throughout both summer and fall work, heavy rains frequently rendered the farm fields where we had to work impassible and our trenches inundated. In mid-October, a snowfall of several inches melted quickly, but contributed to the soft ground, high water table, and swollen waterways. The region was experiencing high river levels typical for spring, but in October. Our sites did not flood, but they were very wet and muddy more often than not, and our trenches turned into swimming pools.

Figure 2 – Commonwealth personnel Jeff Pulvermacher and Dr. Rick Edwards documenting a possible cultural feature near the Maple River, July 16, 2019.

Figure 3 – Same location with pooled rainwater, July 17, 2019.

Figure 4 – Deeper trenches inundated by groundwater and snowmelt near the Sheyenne River, October 2019.

Some possible cultural features were documented at the site near the Maple River during geophysical testing, but we are uncertain whether they are truly of human origin. It was only in October that additional trenching for the data recovery at the site near the Sheyenne River —trenches excavated by peeling back thin layers of soil, but in wider swaths than for the geophysical testing—finally revealed potential cultural features similar to the hearth found during the Phase II investigation. These features consisted of reddish thermally altered soil, white and gray ash, and charcoal—all evidence of burning. Most appeared to have been heavily disturbed by rodent burrowing, with the different burned materials occurring in small patches amid the rodent runs and not arranged as would be expected for a campfire. Feature 10, however, was a more or less intact hearth feature. Like the Phase II hearth feature from 2012, Feature 10 consisted of a layer of white ash sitting atop a layer of reddish burned earth. Pieces of charcoal were found scattered over a wide area around the feature.

Figure 5 – Feature 10 in profile, with white ash on top of a layer of reddish burned earth. This was exciting.

Unfortunately, Feature 10 and many of our less intact features were located below the water table (Feature 10 was roughly 120 centimeters, or 4 feet, below the modern surface) and groundwater quickly began to infiltrate our trench floors, turning the feature materials to pudding if we didn’t excavate fast. Sumps and drains were dug to direct the water away from each feature as much as possible, but feature documentation proved to be very difficult. Other than animal bone (much of it presumably bison) we recovered almost no artifacts from below the surface.

Analysis of both artifacts and the geologic context of the two sites is ongoing. While we do not have diagnostic artifacts associated with the burning features, we hope to determine some temporal associations for both cultural features and former ground surfaces by carbon dating some of our charcoal and bison bone samples. That will make the mud and wet feet worth it.

Figure 6 – Rimsherd from the modern surface.

 

 

 

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