International Osoyoos Lake Board of Control Celebrates 75 Years

Image of Andrew Gendaszek
Andrew Gendaszek
Osoyoos Lake Board of Control
Image of Martin Suchy
Martin Suchy
Osoyoos Lake Board of Control
November 23, 2021

2021 marks the 75th anniversary of the International Osoyoos Lake Board of Control, which was established by order of the International Joint Commission (IJC) on September 12, 1946, in response to prior flooding of Osoyoos Lake’s shoreline, particularly during the summer of 1942.

Establishing a Board of Engineers for Osoyoos Lake occurred 100 years after the 1846 Oregon Treaty between the United States and the United Kingdom. This established the 49th parallel, which bisects the lake, as the international boundary between what would become Washington state and the province of British Columbia.

Over the 75-year history of the International Osoyoos Lake Board of Control, the dam regulating Osoyoos Lake levels, orders governing management of Osoyoos Lake levels and the composition of the board have reflected changing social, cultural and environmental needs of our society.

As both nations continue to adapt to a shifting climate with more extreme droughts and floods, changing demands for water and the need to protect fish supported by Osoyoos Lake, the board and the Order it is tasked to oversee must continue to adapt.

Prior to 1927, outflow from Osoyoos Lake had two natural controls: the discharge capacity of the Okanogan River and, during periods of high water, the level of the Similkameen River that can create backwater of the Okanogan River.

A map of the Similkameen and Okanagan basins
A map of the Similkameen and Okanagan basins. Credit: IJC

In 1927, the Zosel Lumber Co. constructed a rock-filled timber crib and piling dam, now referred to as Zosel Dam, across the Okanogan River to impound a log storage mill pond for an adjacent sawmill.

Although not considered during its original construction, the effect Zosel Dam had on Osoyoos Lake levels on both sides of the border became increasingly apparent during several floods.

This resulted in a formal application for the operation of the dam to the IJC, warranting a pair of hearings in the summer of 1943 and leading to a formal engineering evaluation by a binational Board of Engineers appointed by the IJC.

The engineers’ report provided the technical basis for alterations to Zosel Dam to allow sufficient capacity to maintain Osoyoos Lake at levels agreed to by both nations. It also created the International Osoyoos Lake Board of Control, which was initially comprised of two members from the engineering services of the governments of Canada and the United States, to oversee orders governing the operation, maintenance and capacity of Zosel Dam.

The board membership has included seven Canadian co-chairs in 75 years, beginning with C.E. Webb (district chief engineer, Dominion Water and Power Bureau, Department of Mines and Resources of Canada) in 1946.

The position is currently occupied by David Hutchinson (regional chief, National Hydrological Services, Environment and Climate Change Canada). In 1946, the US section was chaired by Col. L. H. Hewitt (Seattle District engineer, US Army Corps of Engineers) and has seen eight co-chairs since then, although two were appointed on separate occasions. The current U.S. section chair is Dr. Cynthia Barton (director, Washington Water Science Center, US Geological Service), who has been in the role since 2000.

A New Zosel Dam

By the 1970s, the original Zosel Dam was deteriorating and near the end of its useful life. The physical structure of the dam was tested by severe flooding in 1972 and 1974, necessitating emergency repairs, and a severe drought in 1977, which required increased water storage in Osoyoos Lake.

These conditions revealed a need for the board to expand beyond its federal membership to include people from the state of Washington and the province of British Columbia, which occurred in 1978. The longest-serving board member, Kris Kauffman of the U.S. section, joined during this expansion and continues to serve today.

Both nations also recognized the need to replace the aging Zosel Dam and issued new orders for Osoyoos Lake to specify the capacity of the new dam and range of allowable regulated lake levels. The United States and Canada jointly funded and shared responsibility for the construction of a modern control structure comprised of four gates and two fish ladders to allow for redundancy in operations. The new Zosel Dam was commissioned in 1988 and is located about 200 meters (656 feet) upstream of the original dam location.

zosel dam 2008
The current Zosel Dam in 2008. Credit: Osoyoos Lake Board of Control

Following an update of the orders in 2013 that included additional criteria for declaring drought, expanding the range of allowable lake levels and incorporating adaptive management to meet ecological demands, the board was expanded in 2015 to include two additional members from both the United States and Canada, bringing the total membership to 10 people.

This inclusion of local members, including Indigenous representation, has allowed board deliberations to include the perspective and knowledge of people living along and near Osoyoos Lake. As the board enters the 2020s, members are working to proactively address projected changes in flow seasonality and lower snowpacks, and determine the best ways to manage Osoyoos Lake water levels in a shifting climate.

Image of Andrew Gendaszek
Andrew Gendaszek
Osoyoos Lake Board of Control

Andrew Gendaszek is US secretary of the International Osoyoos Lake Board of Control.

Image of Martin Suchy
Martin Suchy
Osoyoos Lake Board of Control

Martin Suchy is Canadian secretary of the International Osoyoos Lake Board of Control.