The good news: work on a permanent fix to a crater-lake sinkhole that developed on Saskatoon's Saskatchewan Crescent in early 2016 is nearly finished.

The corner of 16th Street East and Saskatchewan Crescent as it looks today. (Guy Quenneville/CBC)

The bad news: the project is over budget by more than $900,000.

The City of Saskatoon will ask city councillors next week to give their initial nod for the extra $917,266 (including PST) for the project.

A retaining wall was installed to help prevent further ground shifting. (Guy Quenneville/CBC)

A retaining wall was installed to help stave off further slumping of the ground at the corner of 16th Street East and Saskatchewan Crescent.

The slumping also affected the slope leading down to the South Saskatchewan River, in area taken up by part of the Meewasin Trail.

More unstable soil than expected

Reid Corbett, the city's director of water, said the biggest factor driving up the cost was the fact that there was more unstable soil that needed replacing than initially anticipated.

"Until you start digging and exposing the subsurface, you really don't have certainty on the quantity and the moisture content you're working with," said Corbett.

"And in this case, once we started excavating, we had to excavate larger than anticipated quantities. It was about 2.4 times as much soil having to be removed [and replaced with stable soil.] That was a substantial amount of money that wasn't predicted."

The extra money will go to engineering consulting company Golder Associates and the construction work of Celta Construction Inc., the contractors on the project.

More work needed

The money will also help pay for work that still needs to be done between now and late October on the lower part of the riverbank, between the lower Meewasin Trail and the river.

Stabilization work will take place on the lower bank beneath the corner of 16th Street and Saskatchewan Crescent, until the end of October. (Guy Quenneville/CBC)

"Runoff from the spring of 2017 and rain events resulted in erosion and further slumping along the lower bank from the newly installed outfall from 16th Street," according to the city's report.

"This area requires further remediation to protect the slumping from regressing further along the bank or upslope."

A new sidewalk was installed where the sinkhole used to be. (Guy Quenneville/CBC)

Otherwise, a new sidewalk has been installed on the crescent, plus new paving on the street itself where the sinkhole used to be.

"We've been monitoring and there's very little movement of the slope or anything like that," said Corbett. "The intention is it's a permanent fix."