A Canada-U.S. organization responsible for the Great Lakes has agreed to speed an investigation into whether erosion from dredging caused water levels in Lakes Huron and Michigan to decline to near-record lows.

In response to pressure from policy makers on both sides of the border, the International Joint Commission announced Thursday it will provide its findings on the reasons behind the water loss by February 2009, a full year ahead of schedule.

"The commission understands the urgency of getting answers based on sound science as soon as possible," said former deputy prime minister Herb Gray, the Canadian co-chair of the commission.

The $17.5 million study, launched in 2006, was prompted by two reports from the Georgian Bay Association, which represents about 17,000 people living on the Canadian bay of Lake Huron.

The association said a potential culprit for the lower water levels was dredging done in the St. Clair River in the 1960s when the St. Lawrence Seaway was being completed.

The theory is that the dredging led to accelerated erosion, causing a loss of 9.5 billion litres of water daily from Lakes Huron and Michigan.

The St. Clair River connects Lake Huron to Lake St. Clair and forms part of the international boundary separating Michigan from Ontario.

Seven U.S. senators from the Great Lakes region also sent the International Joint Commission a letter in September asking for an expedited study.

Drought and evaporation are also being investigated as potential causes of the water level drop.

Lakes Huron and Michigan are at their lowest levels since the 1960s and Lake Superior is at its lowest since 1926, according to a report from the Canadian Hydrology Service at Burlington, Ont.

The lower Great Lakes, Lake Ontario and Lake Erie, remain at or slightly above normal levels.

With files from the Associated Press