The Great Lakes Water Balance
Data Availability and Annotated Bibliography
By Brian P. Neff and Jason R. Killian

Introduction | Hydrological Information | Forecasts and Summary

Diversions - Ogoki / Long Lac

The Ogoki and Long Lac diversions redirect water that would normally flow into the Hudson Bay drainage basin to the Lake Superior basin (figures 3 and 4). The Ogoki diversion moves water through the Little Jackfish River, Lake Nipigon and the Nipigon River into Lake Superior at a point 96 kilometers east of Thunder Bay. Three hydroelectric plants on the Nipigon River utilize this diverted water. The Long Lac diversion redirects water through Long Lake and the Aguasabon River into Lake Superior near Terrace Bay. The Long Lac diversion provides water for the hydroelectric plant near Terrace Bay and to drive pulpwood logs down the river. The Ogoki Diversion redirects a drainage basin over three times larger than that of the Long Lac Diversion. Together, the Long Lac and Ogoki diversions increase water supply to Lake Superior at the rate of approximately 5580 cfs (158 cms). This is over 70% greater than all current diversions out of the Great Lakes basin combined. (IJC 1999, p. 10) 

Data for the Ogoki and Long Lac Diversions are available directly from Ontario Power Generation (OPG) in electronic format. The Ogoki Diversion data are subjected to some quality control measures, while the Long Lac Diversion data are generally assumed to be accurate without any quality control measures. It is important to note that these data are not available on the HYDAT CD-ROM, and must be obtained from OPG. 

These data are for the actual diverted flows, and not the actual amount of water entering Lake Superior via the Nipigon River and the Aguasabon River. In fact, there is great uncertainty regarding the amount of the diverted flows that ever actually gets to Lake Superior. As previously stated, the Ogoki Diversion channels water into Lake Nipigon via the Little Jackfish River. Lake Nipigon is a large lake, covering over 4500 km2, and having a maximum depth of 165 m. The average residence time for water entering Lake Nipigon is 2.7 years. After leaving Lake Nipigon, water flows through the Aguasabon River to Lake Superior. It is unclear how the diverted flows from Ogoki are affected in this system.

References

• Bibliographies of selected references

• Full reference list

• Sources of Hydrological data and information

This report is prepared by USGS in cooperation with the Great Lakes Commission.

The Great Lakes Commission is a  multi-agency, multi-disciplinary, multi-faceted team approach to addressing the science and policy of a Great Lakes water management regime will produce such application-oriented products as a water use web site, updated annual water use inventories, ecological evaluations of the system, and an integrated binational role for future Great Lakes-St. Lawrence endeavors.