Souris record at Westhope, key gauge corrected
High water is slowly beginning to recede in the lower Souris River Basin in North Dakota and an often-watched U.S. Geological Survey river gauge that was giving faulty readings has been adjusted.
A slowly moving rainstorm pummelled the Souris River Basin, particularly over the drainage affecting lower portions of the Souris in North Dakota and Manitoba, June 28 and 29. As a result the Souris River at Westhope soared from approximately 9 feet to just under 17 feet in about five days.
According to the National Weather Service the Souris officially peaked at the Westhope gauge at 16.94 feet on Sunday, July 6. The level marked the fifth highest crest in history for that section of the Souris, surpassing the 16.9 feet recorded on April 18, 1949. Flows exceeded 7,500 cubic feet per second.
An impediment to high water flows proved to be massive amounts of water that covered farm fields, filled road ditches and flooded roadways and towns in southern Manitoba. High water on the Canadian side of the border acted as a barrier to Souris River flows in North Dakota. For a time the high water in Canada actually caused the Souris to reverse flow.
“It was getting kind of ugly,” said Frank Durbian, Souris River Refuge Complex manager stationed near Upham. “There was nowhere for water to go in Canada. The Souris at Westhope was running backwards.”
According to Durbian, water on the downstream side of a J. Clark Salyer NWR dam near the U.S.-Canadian border was a foot and half higher than on the upstream side. The situation has begun to change slightly but, due to a very level landscape, water has been slow to run off and into the Souris in southern Manitoba where rainfall totals ranged from 5 to 10 inches.
Similar rainfall occurred over the upper reaches of the Souris River drainage, although over a much smaller area. Nevertheless, various coulee and Souris River flows into Lake Darling caused that reservoir to rise quickly, prompting the opening of release gates as a precaution. Initial plans called for opening gates to allow as much as 2,500 cfs of water into the Souris above Minot, but that was later scaled back to a maximum of 2,000 cfs.
USGS gauge readings at Baker Bridge, the first gauge on the Souris below Lake Darling, had been reading as much as 2,530 cfs. That was more than Upper Souris NWR officials had anticipated and caused them to adjust releases downward. However, it was later discovered that the problem was not with the amount of water being released but with faulty readings from the Baker Bridge gauge.
A USGS team was dispatched to the site and removed obstructions that were causing the automated gauge to display incorrect information. The team also took manual readings of Souris River flow and determined the correct cfs number to be 1,940, the same number as displayed by the corrected gauge. The number was further confirmed by a Wednesday reading of 2,060 cfs at the Boy Scout Bridge several miles downstream from the Baker Bridge gauge.
Lake Darling has been dropping steadily since reaching a high of nearly 1,599 feet, due to runoff from the late June storm. Wednesday afternoon Lake Darling stood at 1,597.62 feet. Releases are expected to continue until the reservoir returns to its summer operating level of 1,597 feet. All of the flow increases were easily contained within the banks of the Souris River in the Minot area.