The International Rainy Lake Board of Control this week issued high lake level notices for both Namakan and Rainy Lakes. The cautions come as spring runoff levels peek and more rain is forecasted this week.
Boise Inc. data, as of Tuesday, had the Namakan Lake level at just above flood stage and Rainy Lake rose another half inch to just less than three inches below.
Bob Anderson, Boise public affairs, said it appears that Namakan and Kabetogama lakes have crested but that the net flowage inflow cannot run through the bottleneck of Rainy River at Ranier fast enough to bring the levels down.
The flowage comes from the lakes and tributaries that feed Lac la Croix and Namakan lakes and on through Rainy River toward Lake of the Woods, and eventually lead to Lake Winnipeg.
The Lake of the Woods Control Board issued a similar notice to shoreline property owners that lake levels are up two inches and expected to rise another two to four inches this week.
Anderson said the cresting of lakes is a good sign but he is concerned about the possibility of more rain this weekend that could bring the basin levels back up again. He said the levels through June will depend on how soon and how heavy the rains come at one time.
The early spring snow melt brought high inflows that began to level out last month, and the recent rise is attributed to a steady series of rainfalls.
“The way things are setting up right now, if this continues we will have some pretty high lake levels,” said Edward Eaton, the U.S. engineering advisor to the IRLBC.
“This series of modest events has continued to build the lake levels,” he added. “My expectation is that the inflow will probably continue to go up for a bit more and then it depends on when the dry weather pattern comes.”
IRLBC reports that the Namakan dams were fully open by mid May and the Rainy dam opened the last of its 15 gates on Tuesday. It was closed again Wednesday because the pipes that feed river water to the mill’s fire protection system were above the water level and created a safety issue.
Boise has all seven hydro wheels open at the water plant and all eight at AbitibiBowater are open to maximize flow.
The Namakan levels were at high marks early in May and all of the gates were opened by the end of the month, said Eaton. Rainy Lake has not reached that level yet, but is nearing that mark.
“When Mother Nature provides too much water there is not too much we can do about it,” said Eaton, who co-wrote a report on the high water events of 2001 and 2002.
Boise and International Joint Commission engineers study water level data daily to adjust inflows and outflows. The water level decline stage of late fall and winter produces a decline until the heavy snow melt and spring rain brings peek levels in late May and early June.
Lee Grim, the Falls member of the IRLBC, said that with the gate level up 8.7 inches in one week, the outflow could not help it decline fast enough if continuing rain adds more water to the basin.
Grim said it is common in high water years for people to blame the IJC rule curve change on erratic lake levels. He noted that the levels, along with inflow and outflow charts, have been maintained since 1915 and can be viewed online at http://lakes.bc.com.
The records show similar lack of control in years of high precipitation, or lack of it before the 1949 rule curve or the 2000 update. Grim says data on Lac la Croix, where there are not manmade controls, show similar curves.
Find out which gates are open along with daily flow changes on a recorded line by calling 1-800-509-5253. Other data and reports are online at www.rivergages.com.