WATER LEVEL MANAGEMENT AS AN OPTION FOR IMPLEMENTING THE COASTAL ZONE MANAGEMENT ACT IN THE GREAT LAKES BASIN
Neal E.Thurber - Great Lakes Coalition, Technical Analyst
Keywords: water level, Niagara River, Great Lakes, hydraulics, flow control
In 1921, completion of hydropower and navigation controls on the St. Mary's River resulted in Lake Superior becoming the first Great Lake to have its elevation regulated and controlled. In 1925, J.R. Freeman published an exhaustive study(2) "Regulation of Elevation and Discharge of the Great Lakes" focused on maximizing the hydropower capabilities of the Great Lakes while also raising Great Lakes water levels to enhance hydropower production and shipping. The fundamental strategy of the report was to detail the means by which controlling works may be installed in the Niagara River, just above the Falls, for the purpose of keeping the Great Lakes at elevations near the high water mark of 1838. Such projects augmented the Lake Superior control and were stated to "maximize hydropower production while backing up water in Lake Erie and deepening the St. Clair River for improved shipping"(2).
In 1950, the United States and Canada modified the 1909 Treaty to increase the amount of water which could be taken from the Niagara River for power production. The 1950 Treaty provided additional water flow by setting a 2,832 m3/s flowrate over the Falls from 8am-10pm EST between April 1st and Sep 15th, and a lower flowrate of 1,416 m3/s for all other periods. Once these criteria where met, the remaining Niagara flowrate could be used for hydropower production, through manipulation of existing controls. Thus during summer daylight hours, approximately 2,500-2,800 m/3 of flowrate was available for power generation and during nighttime and winter periods, approximately 3,800-4,200 m3/s was available. Total Niagara flowrate varies 4,800-5,700 m3/s.
From 1954-1962, Ontario Hydro and the New York Power Authority undertook massive construction projects in the Niagara River, similar to those first proposed by Freeman(2). Major projects that harnessed Niagara River flow were the Control Dam, the Buckhorn Dikes, a new Moses-Saunders intake tunnel and associated River deepening to facilitate water flow into the intake tunnel.
In 1960, completion of hydropower and navigation projects on the St. Lawrence River at Cornwall, Ontario resulted in full control of Lake Ontario water elevations. In 1993, the International Joint Commission (IJC) under the 1950 Treaty issued a Directive to raise water levels in the Niagara River's Chippawa Grass Island Pool (CGIP) to between 170.55-171.77m. This level was 0.45m higher than the previously established level in effect for 43 years.
In the 20th century, other smaller projects in the Great Lakes Basin were the diversion of the Long Lac and Ogoki Rivers into Lake Superior for hydropower generation, which adds water to the Basin, and, the Sanitary and Ship Canal at Chicago, the Welland Canal and the New York State Barge Canal located adjacent to the Niagara River which remove water from the Basin. Lastly, various construction projects such as deepening the St. Clair River, construction of the International Railway Bridge and the Peace Bridge in the upper Niagara River, the Black Rock Lock in the upper Niagara River, and various Niagara River landfill projects that restricted the water flow of the upper Niagara River were completed between 1833 and 1934.
CURRENT WATER LEVEL MANAGEMENT PRACTICES
The Board of Controls and the Plans are independent of one another, but by having some common membership, an attempt is made to coordinate Plans in such a manner to provide optimized water resources for hydropower and shipping. Minimizing water level extremes and resultant shoreline flooding and erosion is not considered a primary mandate, dating back to the 1909 Treaty. Because Lake Superior levels are controlled, Lakes Michigan, Huron and Erie are implicitly controlled through the Superior Board of Control and Niagara Board of Control decisions. Lake Ontario, while affected by the Superior and Niagara Board of Control decisions, can maintain water levels solely by timely actions from the St. Lawrence Board of Control.
PROBLEMS WITH CURRENT WATER LEVEL MANAGEMENT PRACTICES
Mandated Board of Control emphasis on shipping and hydropower production has not recognized 20th century shoreline use changes. A recent example of the prioritized mandate that caused shoreline damage was the uncoordinated levels management of the winter of 1992. Here, and in spite of high precipitation in Q3 and Q4 1992, water was not released at maximum levels from Lake Superior and Lake Ontario. When Lake Superior reached its maximum level under Plan 1977-A, controls were opened in Q1 1993 which dramatically raised the levels of the three middle lakes. This action culminated in severe flooding and erosion along Lake Ontario shorelines as delay by the St. Lawrence Board of Control resulted in a dramatic 1m rise in Lake Ontario levels, followed by an equally dramatic 1.2m drop in five months, once controls were opened. Coincident with this time period was an unprecedented lake levels reversal in Q2-Q3 1993 where Lake Erie water levels were lowered and Lake Huron/Michigan levels were raised(6).
In these examples, a combination of independent Board of Controls, Treaty priorities, and lack of understanding nor the ability to utilize Niagara River flow controls resulted in shoreline flooding and erosion along Lakes Michigan, Huron, Erie and Ontario as Plans 1977-A and 1958-A were disjointedly implemented. The incipient point of these shoreline losses was the Lake Superior Board of Control preference to operate Lake Superior water levels at the upper limit of Plan 1977-A, which in turn greatly reduces flow options during control upgrades or periods of high precipitation.
Niagara River flow controls are not available, by Treaty, as a tool for managing water levels on Lakes Michigan, Huron and Erie, in spite of the tremendous capability of these structures to divert and or restrict Niagara River water flow. Two critical events have not been evaluated. One is the interplay between construction of the Buckhorn Dikes, which restrict almost 50% of the Tonawanda Channel in the Niagara River and the operation of the Moses Saunders intake tunnels just adjacent to the Buckhorn Dikes. The interplay of these structures is critical in that while CGIP regulations can be met downstream of the Buckhorn Dikes, water levels upstream of the Dikes are not regulated. Higher water levels upstream of the Dike increases Lake Erie and Lakes Huron and Michigan water levels, outside the purview of the 1950 Niagara Treaty.
The second critical event is the dramatic change in the relationship between Lake Erie water levels and Niagara River flowrate that occurred shortly after the completion of the 1954-1962 Ontario Hydro / New York Power Authority Niagara River projects. Shown below is a graph that compares Lake Erie water levels to measured and calculated Niagara River water flows(5,6) over time. It is clear that a permenant deviation has occurred from 1972 to present, resulting in Lake Erie, and in turn Lakes Huron and Michigan, water levels needing to attain higher elevations in order to provide commensurate water flow through the Niagara River.
Lastly, water level decisions that favor the upper range of current Plans result in accelerated and permanent wetlands loss, such as that experienced in the western end of Lake Erie. There, washed-out islands and wetlands are not replaceable without dramatic climate change.
Since 1909, Great Lakes recreational boating is now estimated at $6.3b annually(3). Great Lakes shoreline value commonly exceeds $6m per kilometer (over 10,000 km of shoreline) with municipal and private infrastructure costs at multiples of the land cost. These values dramatically supersede those envisaged as decision-making criteria in 1909.
While not an important criterion in 1909, water quality and availability in the next century are becoming important issues as groundwater is depleted and contaminated, and population and agriculture needs increase. Clearly, management of Great Lakes water levels with consideration to providing water outside the Basin is a key 21st century issue.
A NEW PLAN FOR GREAT LAKES WATER LEVELS
CONCLUSIONS AND RECOMMENDATIONS
Adopt one comprehensive model for managing Great Lakes water levels, under the auspices of one Board of Control, that also includes balanced NGO representation. Perform analysis of Niagara River flow control structures, and if needed, consider upgrades to the Black Rock Lock to better manage Niagara River water flows and Upper Great Lakes levels.
Neal E. Thurber
36 Ogden Road
Ogden Dunes, IN 46368