Construction in Edmonton's river valley continues to uncover old treasures from the region's history.

Late last week, an archeological excavation team began preliminary digging at the interchange of Groat Road and River Valley Road. Since then, the team has uncovered a few finds, including two prehistoric arrowheads.

“What we found is fairly typical of the area," said Caroline Schettler, a senior engineer with the city. "We’re not surprised by what we found.”

The two arrowheads are different sizes and styles. The larger one is between 3,000 and 3,500 years old. The smaller is between 700 and 1,000.

The team also found animal bones that will need to be dated.

The excavation is being done before the city begins rehabilitation of the Groat Road bridge over the river. Schettler said the city is making sure it does its due diligence by checking for any cultural or historical artifacts before construction begins.

“What we’re doing is basically digging some holes and seeing what we find,” said Schettler, who's overseeing the bridge rehabilitation, set to begin next summer. She doesn't expect the finds to have any impact on the timeline for the project, but could possibly affect the design for roadwork along River Valley Road and the parallel multi-use path.

“We know the areas around the river can be quite sensitive,” said Schettler about why the city performs the pre-construction digs.

The excavation at the site was headed by Gareth Spicer, principal archeologist with Turtle Island Cultural Resources Management. The company, which is regularly hired by the city to do pre-construction digs, has previously discovered prehistoric artifacts in the river valley and around the sites of Edmonton's old forts. Most artifacts end up with the Royal Alberta Museum.