The Pend Oreille subbasin is located in northern Idaho, northwestern Montana, and northeastern Washington. The lake and the upper basin provide habitat to many species of waterfowl, shorebirds, fish, invertebrates, and plants. For further information please visit:

http://www.epa.gov/iwi/hucs/17010214/score.html
Data regarding the health of the lake

http://www.ecy.wa.gov/biblio/wria62.html
A list of publications about the Pend-Oreille basin