Nfld. & Labrador

Natural causes to blame for Mud Lake flooding, concludes independent report

An independent assessment of flooding that damaged scores of homes along the Churchill River says a combination of natural causes led to an ice jam at the mouth of the river.

Gov't says report contains advice to prevent future flooding, and recommends setting up early warning system

An aerial photo shows some of the damage after the Churchill River overflowed its banks in May. (Donald Edmunds)

An independent assessment of flooding that damaged scores of homes in Mud Lake in Labrador has concluded that ice jammed up at the mouth of the Churchill River because of a combination of natural causes, forcing water over the riverbank.

The report — by Karl-Erich Lindenschmidt, a professor at the University of Saskatchewan — was released by the Department of Municipal Affairs and Environment on Monday.

A news release said the report also provides guidance on how to prevent and mitigate future flooding, how to develop community-based monitoring, and how to provide early warning for residents.

About 100 people were forced out of their homes on May 17 when the river swelled its banks. Some of the homes were destroyed.

While the provincial government set aside nearly $3 million for relief, many homeowners were stuck in temporary housing at 5 Wing Goose Bay for months and sought legal advice about a class-action lawsuit.

Dave Brown of KGS Group, left, and Karl Erich Lindenschmidt of the University of Saskatchewan brief Mud Lake residents on their initial findings in September. (Katie Breen/CBC)

Lindenschmidt worked with engineering consultant KGS Group to find out what caused the flooding, and whether the Muskrat Falls project was a factor, as local residents say.

Initial findings released in early September blamed heavy rain and a rapid spring runoff and possible sediment build-up, findings repeated in the final report.

"There was little time for the thick ice cover to deteriorate before the rapidly increasing river flows developed," the authors wrote.

"It is unfortunate that the factors listed above all came together in the same year that the construction at Muskrat Falls could appear to have any potential effect on the river conditions. It is understandable that local residents would associate the flooding with the Muskrat Falls development," they went on to say.

"However, KGS Group has not found any factors that have been significantly influenced by any construction or operation of the Muskrat Falls facilities in 2016 and 2017 and that would have worsened the flood potential at Mud Lake."

The consultants recommend better monitoring of the watershed area and ice conditions to help forecast future ice jams and flooding.

They also recommend a flood management program which would include ice monitoring, an effective communication strategy between the N.L. government, Nalcor and residents, and possible early warning systems.