How a cemetery of early Saskatoon settlers could help find unmarked residential school graves

Researchers from the University of Saskatchewan are hoping to use an historic Saskatoon cemetery to test techniques that could one day help identify unmarked graves at residential school sites.

On Wednesday, city councillors are being asked to approve the project, which would allow anthropology professor Terence Clark to use the Nutana Pioneer Cemetery to test ground penetrating radar and a form of soil probing to refine the techniques used to map grave locations, according to a report to city council.

The Nutana Cemetery is a municipal heritage property, so any work that alters or disturbs the land requires a green light from city council, the report says.

Clark would lead a team of undergraduate and graduate students in completing a ground penetrating radar survey and soil probing of the site to find the borders of known burial sites, “to further calibrate the use of the geophysics techniques.”

“This will enable the technique to be used for locating unmarked graves in the future at other sites,” writes Vanessa Heilman, geotechnical engineering specialist.

Ground penetrating radar emits radio waves into the ground and records the reflections of the signal as they rebound off objects underground that are used to produce a radargram that can be interpreted by researchers, according to a process summary included in the report.

The other technology, called S4 soil probing, allows researchers to see the chemical composition of the soil and to detect changes in pressure underground, which can indicate where the earth was dug out and refilled.

A probe about the diameter of a pencil is pushed into the ground, and light is shone through a sapphire lens at the bottom that analyzes the colour spectra from the soil.

“The probe can detect spectra from fatty acids caused by human decomposition,” city administration writes, making it a useful tools in locating unmarked burials.

Surveyors start with ground penetrating radar, looking for anomalies under the surface.

“Anomalies that meet the expected parameters for unmarked burials are then analyzed with the S4 probe,” the report says.

“Clusters of S4 ‘hits’ in conjunction with lower soil pressure areas and GPR anomalies are very strong indicators of the existence of a burial.”

Researchers from the geophysics and anthropology departments at the U of S have done work in the Nutana Cemetery before, Heilman says, and it would not cause a significant disturbance to the graves.

Since the research could be ongoing, city administration is also asking for council approval to draft a new bylaw that would allow a manager to approve future requests, rather than returning to council every year.

“The techniques proposed in this application could be used in the future for locating unmarked graves at residential schools, which will continue to be sensitive and upsetting for communities, as well as for residential survivors, their families, and the families of children whose location remains unknown. However, this new technology could also help serve to provide closure and validation,” the report says.

If approved, the fieldwork would likely be done before winter.