General Definitions & Abbreviations

bgd: billion gallons per day

bld: billion liters per day

consumptive use: that portion of water withdrawn or withheld from the Great Lakes basin and assumed to be lost or otherwise not returned to the Great Lakes basin due to evapotranspiration, incorporation into products, or other processes (Agreement Article 103; Compact Section 1.2).

Great Lakes surface water (GLSW): the Great Lakes, their connecting channels (the St. Clair River, the Detroit River, the Niagara River and the St. Marys River), and the St. Lawrence River

groundwater (GW): all subsurface water

diversion: a transfer of Water from the basin into another watershed, or from the watershed of one of the Great Lakes into that of another by any means of transfer, including but not limited to a pipeline, canal, tunnel, aqueduct, channel, modification of the direction of a watercourse, a tanker ship, tanker truck or rail tanker but does not apply to water that is used in the basin or Great Lakes watershed to manufacture or produce a product that is then transferred out of the basin or watershed (Agreement Article 103; Compact Section 1.2)

intrabasin transfer: a transfer of water from the watershed of one of the Great Lakes into the watershed of another Great Lake (Agreement Article 103; Compact Section 1.2)

level of accuracy: the quality of data based on percentage of total volume and rated as 1) measured; 2) partially measured or 3) estimated,

level of aggregation: the quality of data based on percentage of total volume and rated as 1) originating from site-specific sources or 2) originating from higher level aggregate sources, such as county or census databases

mgd: million gallons per day

mld: million liters per day

other surface water (OSW): tributary streams, lakes, ponds, and reservoirs within the Great Lakes basin

threshold facility: a facility withdrawing in excess of the Great Lakes-St. Lawrence Compact/Agreement uniform trigger level of 100,000 U.S. gallons/day (380,000 liters/day) averaged over a 30-day period. A threshold facility is determined by the total withdrawal (or consumption) of all sources combined (Great Lakes-St. Lawrence surface water, other surface water, and groundwater) rather than a single source.

tgd: trillion gallons per day

tld: trillion liters per day

withdrawal amount: the taking of Water from surface Water or groundwater (Agreement Article 103, Compact Section 1.2).