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History of the Watershed

The Water Levels of Rainy and Namakan Lakes

Rainy and Namakan Lakes are located along the international boundary of the Ontario, Canada, and the Minnesota, USA, border. These lakes are part of a waterway that extends from the Sawtooth Mountains, which are located about 50 miles inland from Lake Superior, to the Arctic Ocean. The water levels of these lakes are controlled according to regulations set by the International Joint Commission (IJC), an independent international organization established under the Boundary Waters Treaty of 1909, to help prevent disputes regarding use of boundary waters.

A hydroelectric dam located on the Rainy River at Fort Frances, Ontario/International Falls, Minnesota and two water-control dams located at Kettle Falls, Ontario, the outlet of Namakan Lake, maintain lake levels. These structures are owned and operated by H2O Power LP on the Canadian side and by Boise Inc. on the United States side. The companies manage the water levels of Rainy and Namakan Lakes in accordance with the rule curves established by the International Joint Commission. The IJC has delegated the oversight of the rule curves to the International Rainy Lake Board of Control, which has both a U.S. and Canadian representative and technical staff. There is a similar group known as the Lake of the Woods Control Board for that area.

The first rule curves were introduced by the IJC in 1949 after detailed study and public hearings. The serious floods, which occurred in 1950 and 1954 led to a reevaluation and modification of the rule curves in 1957. The rule curves were modified again in 1970 due to high and low water events on Rainy and Namakan Lakes from 1957 to 1968. The latest revisions to the rule curves came on January 6, 2000 after a self appointed group known as the International Steering Committee advocated further changes to the rule curves on both lakes.

The IJC establishes minimum and maximum discharge requirements in order to avoid “emergency conditions” as much as possible. Emergency conditions are defined to exist when the levels of Rainy and Namakan Lakes are higher than 1108.1 feet above sea level (337.75 meters) and 1118.6 feet (340.95 meters) respectively and inflows exceed the discharge capacity of the dams. Emergency conditions also occur when Rainy Lake is below 1104.6 feet (336.68 meters) and Namakan Lake is below 1108.6 feet (337.90 meters) and minimum discharges are in effect.

The maximum discharges through the dams on both lakes can at times be exceeded by the inflows into the two lakes. On Rainy Lake, there is a natural flow constriction located at the outlet of Rainy Lake or otherwise known as the Ranier rapids. A greater volume of water can be discharged through the International Falls/Fort Frances dam than can come through this natural constriction. This can cause the level of the Rainy River to drop in elevation between the outlet of Rainy Lake and the dam.

General Watershed Information

General Watershed Information

All of the gauges located throughout the basin are owned and operated by various Canadian and U.S. federal agencies, including Environment Canada, the United States Geological Survey, and the Canadian Lake of the Woods Control board.

Data Collection

The level of Rainy Lake is measured at Environment Canada gauges located east of Fort Frances, at the “Five Mile Dock” and at “Bears Pass”. The level of Namakan Lake is measured at an Environment Canada gauge upstream of the International Dam at Kettle Falls.

In addition to the data collected by the network of gauges, H2O Power LP and Boise Inc. also access the Monthly and Seasonal Outlook from the U.S. National Weather Service, which provides general trends, and the Ontario Hydro Snow Survey, which provides measurements in the early spring of the depth and moisture content of the snow cover in the watershed.

The companies also calculate inflow into the two lakes through a formula devised by their hydrologic consultant and outflows of the dams on both lakes.

Snow and Precipitation

Precipitation data alone is not a good indicator of predicting inflow into the lakes and must be coupled with other factors to change the discharges from the dams. Some of the reasons for this are that precipitation can be very localized and not represent conditions over large areas of the watershed. Because of the size of the lakes, precipitation over a few hours or days may not impact lake levels.

Typically only one-third of the spring run-off is from snowmelt, while two-thirds is directly from the amount of rainfall during April, May and June.

  • Frost in the Ground – The extent of the frost in the ground in the early spring affects the rate of infiltration of precipitation and/or snowmelt and therefore influences the magnitude of the runoff into the lakes.
  • Ground water saturation – After prolonged periods of rainfall the ground becomes saturated and increases the amount of water that will enter the lakes from subsequent rains.
  • Evaporation – Evaporation from the lake surfaces and from the surrounding land is significant and variable. It is estimated that on average about two feet of lake level is lost directly to the atmosphere each year due to evaporation from the lake surfaces. More than .4 inches or one centimeter can be lost to evaporation on a warm, windy day in August, and at times the volume of water lost can actually exceed the lake inflows during that period.
  • Wind effects – Wind causes the lake surface to “tilt” slighty and complicates the determination of the true overall average lake level. It is believed that a moderate wind from the west can raise the lake level at the east end of the Rainy Lake by two inches or five centimeters or vice versa if the wind is from the east. This can affect the calculation of inflow, which in turn is used to calculate outflow decisions.
  • Downstream effects – Rapid, large changes in outflow from Rainy Lake cause swings in the water levels of Rainy River downstream of the dam. This situation can be magnified by increased flows entering the river from the Littlefork, Bigfork, Black and Rapid rivers. Late winter flow changes can be a problem for the ice fisherman in the Birchdale area. Summertime changes can be a problem for boat and plane owners upstream of the dam especially if the changes include spillway gate openings or closings.
  • Local radio stations in International Falls and Fort Frances broadcast spillway gate changes affecting the outflow through the dam.

Watershed Statistics

Rainy Lake watershed information

Area upstream of International Falls

  • 14,500 square miles (37,555 square kilometers) total area
  • 10,135 square miles (26,250 square kilometers), or 70%, in Canada
  • 4,365 square miles (11,305 square kilometers), or 30%, in the United States
  • 2,025 square miles (5,245 square kilometers) water
  • 12,475 square miles (32,310 square kilometers) land


International Falls/Fort Frances Dam

  • Controls the level of Rainy Lake
  • The dam straddles the Canadian/United States border
  • United States side (Boise Inc. owned and operated)
  • 7 hydroelectric waterwheel generators
  • No spillway gates
  • Canadian side (H2O Power LP owned and operated)
  • 8 hydroelectric waterwheel generators
  • 15 spillway gates
  • Water is shared between the two owners


Namakan Lake watershed information

Area upstream of Kettle Falls

  • 7,200 square miles (18,648 square kilometers) total area
  • 3,290 square miles (8,521 square kilometers), or 46%, in Canada
  • 3,910 square miles (10,127 square kilometers), or 54%, in the United States
  • 1,000 square miles (2,590 square kilometers) water
  • 6,200 square miles (16,058 square kilometers) land


Kettle Falls and Squirrel Falls Dams

  • Control the level of Namakan and Kabetogama Lakes
  • The Kettle Falls Dam straddles the Canadian/United States border
  • United States side (Boise Inc. owned and operated)
  • 2 spillway gates
  • 1 fish ladder spillway gate (always open)
  • No hydroelectric waterwheel generators
  • Canadian side (H2O Power LP owned and operated)
  • 2 spillway gates
  • No hydroelectric waterwheel generators
  • The Squirrel Falls Dam is entirely in Canada (H2O Power LP owned and operated)
  • 4 spillway gates
  • 1 fish ladder spillway gate (always open)
  • No hydroelectric waterwheel generators

Lake Maps and Lake Levels

Lake Maps and Lake Levels

Lake maps
A link to the Lake of the Woods Control Board website, which provides a detailed basin map, a drainage basin schematic and a basin profile.

Rainy Lake level
A link to the rule curves and current elevation for Rainy Lake.

Namakan Lake level
A link to the IJC curve and current elevation for Namakan Lake.

Monthly lake level data
A link to Rainy Lake and Namakan Lake monthly minimum and maximum limits for a full year.

International Falls powerhouse – daily data
This link provides water levels for the head pond and the tailrace, as well as data for the water flow and temperature. Data provided is for the past ten days up through yesterday’s date.

 

For information on lake levels or outflows, contact:

Boise Paper, International Falls, Minnesota
Lori Lyman
Phone: 218 285 5312

Sam Cassibo
Phone: 218 285 5737

H2O Power LP, Fort Frances, Ontario
Marc Mantha
Phone: 905 438 8539, ext: 203

Lake of the Woods Secretariat
Phone: 800 661 5922

Borderland Lakes Information

Boise Inc. provides this information for you about the lakes and rivers in the Rainy River Basin of Northern Minnesota and Northwestern Ontario. The information shared on these pages is the result of a collaborative relationship between government agencies and organizations from both Canada and the United States.

For information on Rainy and Namakan Lake levels, visit the following: