Over the past several years, stakeholders located around the Great Lakes have sounded the alarm over receding shorelines and declining water levels. Ships that sail the St Lawrence Seaway and Great Lakes have had to carry reduced payloads as a means of assuring sufficient clearance with the riverbed or lakebed. During the summer of 2010, one ship ran aground in a traditional shipping channel in Lake Ontario and a second ship ran aground in a navigation lock near Montreal. Several stakeholders have called for the installation of navigation locks along the Lower St Lawrence River to simultaneously reduce water volume flow rate and assure sufficient navigation depth.

An article published earlier this year by Lake Ontario Waterkeeper described methods by which to reduce water flow volume at several points along the Lower St Lawrence River. Marine navigation contributes to the economy of Montreal and several other cities located upstream of Montreal and will come to depend on reducing water flow volumes through the Lower St Lawrence River and into the Gulf of St Lawrence. There is additional scope to reduce water flow volume along the Upper St Lawrence River from Lake Ontario to Montreal.

There are complimentary methods that the marine transportation industry that the hydroelectric power generation industry may implement over the long-term to allow for both industries to remain viable as less water flows through the Upper St Lawrence River. The power generation industry may have to decrease hydroelectric output and store electrical energy through pumped hydraulic energy storage along the river. At the present time, Hydro Quebec has limited capacity for pumped hydraulic energy storage at their James Bay facilities, between La Grande Reservoirs #2 and # 3.

Power Industry:

There is scope for Hydro Quebec, Power Authority of New York and Ontario Power Generation to eventually implement pumped hydraulic energy storage between the Gulf of St Lawrence and Lake Ontario. Such initiatives would follow initiatives to reduce water flow volumes along the Lower St Lawrence River. The combined reduction in water volume flow rate along the Lower and Upper St Lawrence River would greatly assist the possible operation of pumped (underground) hydraulic energy storage (http://www.riverbankpower.com) between the Gulf of St Lawrence and Lake Ontario.

The optimal locations for pumped underground energy storage installations would be immediately downstream of large power dams (Beauharnois and Moses Saunders). Underground turbines and reservoirs would be located some 600m below river surface and with over 20-times the head of the Beauharnois and Moses Saunders dams. The underground installations could generate equivalent output as the power dams during peak demand periods using less than 5% of the water volume flow rate. During the overnight off-peak periods, the Kaplan turbines would return that water to river surface. A similar energy storage system may be installed under the City of Toronto.

Marine Industry:

The marine transport industry could assist in conserving water along the Upper St Lawrence River by introducing side-reservoirs at the navigation locks located between Montreal and Lake Ontario. Side-reservoirs were introduced on the European barge canal system to reducing the volume of water required to allow barges to traverse navigation locks. The designers of the upgraded Panama Canal ship navigation system will include the European side-reservoir system so as to reduce water usage as the new generation of larger ships traverses the system of locks.

Each lock along the upgraded European barge canal system includes its own companion side-reservoir, with a hydraulic turbine driving a hydraulic pump at the lock outlet. When a barge is moved downstream to lower elevation in the lock, water flows through the outlet turbine to lower elevation and drives the pump to transfer water into the side-reservoir. A barge that is moving upstream will enter the emptied lock and the gates close behind it. As it is raised to higher elevation, water will in from its side-tank until reaching an equilibrium point, when additional water will flows in from the upstream lock and through an inlet turbine will drives a water pump that will transfer an additional volume of water from the side reservoir and into the active lock.

The use of side-reservoirs can re-use up to 2/3rd the volume of water that would otherwise flow downstream. Each navigation lock along the St Lawrence Seaway has an estimated volume of some 43,500m3 (cubic meters)) and releases some 6500m3 of water downstream per downstream sailing. The introduction of side-reservoirs could reduce water usage by some 4000m3 per downstream sailing and release up to 2500m3 (88,000 cu. ft) of water downstream instead of 6500m3 (230,000 cu. ft) of water. There is scope to upgrade the St Lawrence Seaway system to conserve water while providing passage through the locks to the existing size of lake vessels.

Reducing Water Usage:

Water in rivers and streams that flow into the Great Lakes and the St Lawrence River system sustains much agricultural production. Many farmers (and homeowners) have begun to introduce underground watering systems to conserve water in regions where water usage incurs high tariffs. Many homebuilders, developers and renovators have begun to introduce lower-flow toilets into new homes. There is scope to re-use water from bathrooms and kitchens to sustain gardens and related plant growth at numerous locations along many of the rivers and streams that flow into the Great Lakes and the St Lawrence River, as well as at communities located along the shores of the Great Lakes and St Lawrence River.

Upstream Energy Storage:

The initiatives that are possible to reduce water consumption between Lake Ontario and the Gulf of St Lawrence may provide opportunity for seasonal energy storage between Lake Ontario and Lake Erie. There is a control dam at Niagara Falls that can literally allow water to stop flowing over the waterfalls during the overnight off-peak hours during the winter months. Lake Erie has the capacity to hold much higher water volumes than it presently holds.

Ontario Power Authority and New York Power Authority divert water through tunnels from Lake Erie and though hydraulic turbines located at the elevation of Lake Ontario. A small amount of pumped hydraulic energy storage does operate at Niagara. It and its pumping turbines were built during a much earlier era and can only operate over a fraction of the height of the falls. Modern Kaplan hydraulic turbines built during a later period are able to pump water uphill over the full height of the falls and have successfully operated at the Ludington pumped hydraulic installation in Michigan.

Powerful winds blow overnight during winter over the Great Lakes and some 400-Km of coastline in Northern Ontario along Hudson Bay. Overnight winter wind energy may be used to pump water overnight from Lake Ontario into Lake Erie, using the existing tunnels. Electrical equipment at Niagara would require modification in order to drive Kaplan turbines in pumping mode. Peak demand for electric power occurs during summer in both Ontario and New York State. Initiatives to reduce water loss from Lake Ontario to the Gulf of St Lawrence could assure sufficient summertime electric power at Niagara and viable ship operation along the St Lawrence River.