Glossary of Terms

ADAPTIVE MANAGEMENT
A planning process that can provide a structured, iterative approach for improving actions through long-term monitoring, modeling and assessment. Through adaptive management, decisions can be reviewed, adjusted and revised as new information and knowledge becomes available or as conditions change.

AKWESASRONON
Members of the Mohawk Nation at Akwesasne.

ArcGIS
A family of client software, server software, and online geographic information system (GIS) services developed and maintained by Esri. ArcGIS was first released in 1999 and originally was released as ARC/INFO, a command line based GIS system for manipulating data.

AUTHORITY
The right to enforce laws and regulations or to create policy.

AVERAGE WATER LEVEL
An arithmetic average of past observations of water levels for a given time period (e.g. monthly) and a certain period of record (e.g. 1918 through 2020).

BASIN; WATERSHED
The region or area of which the surface waters and groundwater ultimately drain into a particular course or body of water.

BASIN (GREAT LAKES-ST. LAWRENCE RIVER)
The surface area contributing runoff to the Great Lakes and the St. Lawrence River downstream to Trois Rivières, QC.

BENTHIC INVERTEBRATES
Benthic (meaning “bottom-dwelling”) macroinvertebrates are small aquatic animals and the aquatic larval stages of insects. Examples in the Great Lakes include dragonfly and stonefly larvae, snails, worms, beetles, crayfish and freshwater mussels.

BLUFF
A steep bank or cliff or variable heights, composed of glacial tills and lacustrine deposits consisting of clay, silt, gravel and boulders.

BOUNDARY WATERS TREATY OF 1909
The agreement between the United States and Canada that established principles and mechanisms for the resolution of disputes related to boundary waters shared by the two countries. The International Joint Commission was created as a result of this treaty.

CHART DATUM
The water level used to calculate the water depths that are shown on “navigation charts” and are a reference point for harbor and channel dredging. Also known as Low Water Datum.

CLIMATE
The prevalent weather conditions of a given region (temperature, precipitation, wind speed, atmospheric pressure, etc.) observed throughout the year and averaged over at least 30 years.

CLIMATE CHANGE
A non-random change of climate that is attributed directly or indirectly to human activity, that alters the composition of the global atmosphere, and which is in addition to natural climate variability observed over comparable time periods.

COAST
The land or zone adjoining a large body of water.

COMPUTER MODELLING; COMPUTER MODEL
The use of computers to develop a series of equations and mathematical terms based on physical laws and statistical theories that simulate complex natural systems or processes.

CONSERVATION AUTHORITY
Local watershed management agencies within the Province of Ontario that deliver services and programs to protect and manage impacts on water and other natural resources in partnership with all levels of government, landowners and many other organizations.

DECISION SUPPORT TOOL
Refers to a wide range of computer-based tools (simulation models, and/or techniques and methods) developed to support decision analysis and participatory processes. A DST consists of a database, different coupled hydrodynamic and socio-economic models and is provided with a dedicated interface in order to be directly and more easily accessible by non-specialists (e.g. policy and decision makers).

DEVIATIONS; OUTFLOW DEVIATIONS
Temporary changes in outflows (from Lake Ontario) that differ from those prescribed by a regulation plan that are intended to provide beneficial effects or relief from adverse effects to an interest, without causing appreciable adverse effects to any of the other interests.

DIRECTIVE
An IJC instruction to a new or existing Board or Committee specifying their terms of reference, including tasks and responsibilities.

ECOSYSTEM
A biological community in interaction with its physical environment, and including the transfer and circulation of matter and energy.

ENVIRONMENT
Air, land or water; plant and animal life including humans; and the social, economic, cultural, physical, biological and other conditions that may act on an organism or community to influence its development or existence.

EROSION; COASTAL EROSION; SHORELINE EROSION
The wearing away of land surfaces through the action of rainfall, running water, wind, waves and water current. Erosion results naturally from weather or runoff, but human activity such as the clearing of land for farming, logging, construction or road building can intensify the process. Coastal or shoreline erosion refers to the wearing away of a shoreline as a result of the action of water current, wind and waves.

FLOODING
The inundation of low-lying areas by water.

FLOODPLAIN
The lowlands surrounding a watercourse (river or stream) or a standing body of water (lake), which are subject to flooding.

FOREBAY
A forebay is an artificial pool of water in front of another body of water. For the purposes of this report, forebay refers to Lake St. Lawrence, a widening and deepening of the St. Lawrence River directly upstream of the Moses-Saunders and Long Sault dams created during the construction of the dams by permanently flooding a large portion of land (see https://ijc.org/en/loslrb/lake-st-lawrence).

FRAZIL ICE
Ice with the consistency of slush, formed when small ice crystals develop in supercooled water as air temperatures drop below freezing. These ice crystals join and are pressed together by newer crystals as they form.

FRESHET
The sudden overflow or rise in water level as a result of heavy rains or snowmelt.

GEOGRAPHIC INFORMATION SYSTEM (GIS)
A conceptualized framework that provides the ability to capture and analyze spatial and geographic data. gis applications are computer-based tools that allow the user to create interactive queries (user-created searches), store and edit spatial and non-spatial data, analyze spatial information output, and visually share the results of these operations by presenting them as maps.

GREAT LAKES-ST. LAWRENCE RIVER ADAPTIVE MANAGEMENT (GLAM) COMMITTEE
A Committee of the International Joint Commission applying an adaptive management approach to the review of the outflow regulation plans for Lake Superior and Lake Ontario. The committee reports to the International Lake Ontario-St. Lawrence River Board, the International Lake Superior Board of Control and the International Niagara Board of Control.

HABITAT
The particular environment or place where a plant or an animal naturally lives and grows.

HAZARD ZONES
An area of land that is susceptible to flooding, erosion, or wave impact.

HERPETOFAUNA
The reptiles (e.g. turtles) and amphibians (e.g. frogs) of a particular region, habitat, or geological period

HYDRAULICS
The study of the mechanical properties of liquids, including energy transmission and effects of the flow of water.

HYDRAULIC MODELING
The use of mathematical or physical techniques to simulate water systems and make projections relating to water levels, flows and velocities.

HYDROCLIMATE
The study of the influence of climate upon the waters of the land including the energy and moisture exchanges between the atmosphere and the Earth’s surface and energy and moisture transport by the atmosphere.

HYDROELECTRIC POWER
Electrical energy produced by the action of moving water.

HYDROLOGIC CYCLE; WATER CYCLE
The natural circulation of water, from the evaporation of water into the atmosphere, the transfer of water to the air from plants (transpiration), precipitation in the form of rain or snow, and runoff and storage in rivers, lakes and oceans.

HYDROLOGIC MODELING
The use of physical or mathematical techniques to simulate the hydrologic cycle and its effects on a watershed.

HYDROLOGY
The study of the properties of water, its distribution and circulation on and below the earth’s surface and in the atmosphere.

ICE JAM
An accumulation of river ice, in any form which obstructs the normal river flow.

INDIGENOUS
Originating or occurring naturally in a particular place; native. In this report Indigenous refers to the First Nations, Tribal Nations and Métis Nations of North America.

INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE (IPCC)
The United Nations body for assessing the science related to climate change.

INTERNATIONAL GREAT LAKES DATUM (IGLD)
The elevation reference system used to define water levels within the Great Lakes-St. Lawrence River basin. Due to the movement of the earth’s crust, the “datum” must be adjusted every 30-40 years.

INTERNATIONAL JOINT COMMISSION (IJC)
International independent agency formed in 1909 by the United States and Canada under the Boundary Waters Treaty to prevent and resolve boundary waters disputes between the two countries. The IJC makes decisions on applications for projects such as dams in boundary waters, issues Orders of Approval and regulates the operations of many of those projects. It also has a permanent reference under the Great Lakes Water Quality Agreement to help the two national governments restore and maintain the chemical, physical, and biological integrity of those waters.

INTERNATIONAL REACH
The portion of the St. Lawrence River that is between Lake Ontario and the Moses-Saunders Dam.

INTERNATIONAL LAKE ONTARIO – ST. LAWRENCE RIVER BOARD
Board established by the International Joint Commission originally in its 1952 Order of Approval and renamed from the “International St. Lawrence River Board of Control” in 2017 with the implementation of Plan 2014 and the revised Order of Approval. Its main duty is to ensure that outflows from Lake Ontario meet the requirements of the Commission’s Order.

IMPACT ZONE
Water level or flow ranges where impacts to an interest or use can be low, moderate, major, severe or extreme. Impact zones are based on a series of data and information sources and are meant to show the type and breadth of impacts at different water level ranges.

LAKE ONTARIO – ST. LAWRENCE RIVER STUDY (LOSLRS)
A study, sponsored by the IJC and completed in 2006, to examine the effects of water level and flow variations on all Lake Ontario-St. Lawrence River uses and interest groups and to determine if better management of Lake Ontario’s outflows is possible.

LIGHT LOAD
A load less than a ship’s capacity. Ships transiting the St. Lawrence Seaway are required to “light load” or carry less than their maximum capacity when a fully loaded ship would otherwise be too close to the channel bottom because of low water levels.

LIMITS
Special rules within a regulation plan that are meant to “limit” (e.g. restrict or increase) the outflow from Lake Ontario under certain conditions to address specific uses and interests on the St. Lawrence River that can be affected by water levels and/or flows there.

LOWER ST. LAWRENCE RIVER
The portion of the St. Lawrence River downstream of the Moses-Saunders Dam is called the lower St. Lawrence. It includes Lake St. Francis, Lake Saint-Louis, Montreal Harbour, Lake Saint-Pierre and the portions of the River connecting these lakes as far downstream as Trois-Rivieres, QC.

MARINA
A private or publicly-owned facility allowing recreational watercraft access to water and offering mooring and related services.

MARSH
An area of low, wet land, characterized by shallow, stagnant water and plant life dominated by grasses and cattails.

NET BASIN SUPPLY (NBS); WATER SUPPLY
The net amount of water entering one of the Great Lakes (e.g. Lake Ontario), comprised as the precipitation onto the lake minus evaporation from the lake, plus runoff from its local basin. The net basin supply does not include inflow from the upstream lake through the connecting channel.

NET TOTAL SUPPLY (NTS)
The Net Basin Supply plus the inflow through the connecting channel from the upstream lake (e.g. the Net Basin Supply to Lake Ontario plus the inflow from Lake Erie through the Niagara River and Welland Canal make up the Net Total Supply to Lake Ontario).

OBLIQUE IMAGERY
Aerial photography that is captured at approximately a 45 degree angle with the ground.

ORDERS OF APPROVAL
In ruling upon applications for approval of projects affecting boundary or transboundary waters, such as dams and hydroelectric power stations, the ijc can regulate the terms and conditions of such projects through Orders of Approval to maintain specific targets with respect to water levels and flows in the lakes and connecting channels.

PERFORMANCE INDICATOR
A measure of economic, social or environmental health. In the context of this report, performance indicators relate to impacts of different water levels in Lake Ontario and the St. Lawrence River.

PRE-PROJECT CONDITIONS; PREPROJECT RELATIONSHIPS
The outflow conditions that would occur without the St. Lawrence Seaway/Moses-Saunders Dam project can be simulated using a stage-discharge relationship between the observed Lake Ontario water levels and outflows that occurred prior to the construction of the project. These conditions and this relationship are known as “preproject”.

PUBLIC ADVISORY GROUP (PAG)
The group of 18 unpaid volunteers from the United States and Canada that worked as representatives of groups that are directly affected by outflow management (including deviations from the regulation plan) to bring their insights of the impacts of extreme high water to the Great Lakes-St. Lawrence River Adaptive Management (GLAM) Committee and ensure effective communication, to help formulate a means of presenting this information to the Board, and to come up with ways to communicate with their constituents about progress of the Phase 1 expedited review of Regulation Plan 2014.

REFERENCE
A request from government for the ijc to study and recommend solutions to transboundary issue. The word is derived from Article IX of 1909 Boundary Waters Treaty, which stipulates that such issues “shall be referred from time to time to the International Joint Commission for examination and report, whenever either the Government of the United States or the Government of the Dominion of Canada shall request that such questions or matters of difference be so referred.”

REGULATION PLANS
In the context of the report, the management of water outflows (from Lake Superior and Lake Ontario) through regulatory structures (on the St. Marys River and St. Lawrence River) following a set of rules and objectives that are intended to meet the needs of various water-using interests in a basin. These plans have incorporated the specific objectives established in the ijc’s Orders of Approval, establish monthly or weekly outflows, and allocate flows to various water-use interests.

REGULATORY STRUCTURES
Adjustable structures, such as a gated dam that can be operated to adjust outflows and influence water levels. In the Great Lakes-St. Lawrence River basin, there are regulatory structures on the St. Marys River at the outlet of Lake Superior and on the St. Lawrence River at the outlet of Lake Ontario.

REVETMENT
A natural (e.g., grass, aquatic plants) or artificial (e.g., concrete, stone, asphalt, earth, sand bag) covering to protect an embankment or other structure from erosion.

RIPARIAN; RIPARIANS
Of, relating to or found along a shoreline. Persons residing on the banks of a body of water. Typically associated with private owners of shoreline property.

RUNOFF
The portion of precipitation on the land that ultimately reaches streams and lakes.

RULE CURVE
Outflows set by Regulation Plan 2014 begin with a sliding “rule curve” based on a pre-project stage-discharge relationship such that as Lake Ontario levels and water supplies increase, outflows increase and as water levels and supplies decrease, outflows decrease.

ST. LAWRENCE SEAWAY
A system of locks, canals, and channels providing an inland waterway capable of accommodating seagoing ships travel from the Atlantic Ocean to the Great Lakes as far inland as Duluth, Minnesota at the western end of Lake Superior.

SHORE WELL
A well close to a lake in which the well water levels are directly influenced by lake levels.

SHORELINE
Intersection of a specified plane of water with the shore.

STAKEHOLDER
An individual, group, or institution with an interest or concern, either economic, societal or environmental, that is affected by fluctuating water levels or by measures proposed to respond to fluctuating water levels within the Lake Ontario–St. Lawrence River basin.

STOCHASTIC SUPPLIES
Statistically generated simulated sequences of water supply conditions based on historical climate variability.

STORY MAP
A web based product that has been thoughtfully created, given context, and provided with supporting information so it becomes a stand-alone resource. It integrates maps, legends, text, photos, and video and provides functionality, such as swipe, pop-ups, and time sliders, that helps users explore the content.

SURGE
A movement of water that happens when a storm (low pressure center) moves across the lake and causes the water to be “pushed” in the same direction the storm is moving. This results in water levels rising at one end of the lake and falling at the other end.

UPPER ST. LAWRENCE RIVER
The portion of the St. Lawrence River upstream of the Moses-Saunders Dam is called the upper St. Lawrence River. It includes the entire river from Kingston/Cape Vincent to the Moses-Saunders Dam and locks at Cornwall-Massena, including Lake St. Lawrence.

USES AND INTERESTS
In the context of the report, the groups or sectors served by the waters of Lake Ontario and the St. Lawrence River, including municipal and industrial water uses, commercial navigation, hydroelectric power generation, coastal development, ecosystems, and recreational boating. Under the Boundary Waters Treaty of 1909, the interests of domestic and sanitary water uses, navigation and hydroelectric generation and irrigation are given order of precedence in water uses in the development and operation of regulation plans.

WATER LEVEL
The elevation of the surface of the water of a lake or at a particular site on the river. The elevation is measured with respect to a certain datum (e.g. International Great Lakes Datum) or average sea level.

WATER LEVEL PROJECTION; WATER LEVEL FORECAST
The projected range of water levels that may be expected to occur under potentially wet, average and dry conditions. Actual water levels will depend primarily on weather and water supplies, and during periods of extreme conditions, may fall outside of the projected range.

WAVE
An oscillatory movement in a body of water which results in an alternate rise and fall of the surfaces.

WETLANDS
An area characterized by wet soil and high biologically productivity, providing an important habitat for waterfowl, amphibians, reptiles and mammals.