The hydro station in Campbell River has been in operation since 1947 and Hydro says it's in need of a remodel.
But negotiations with the K'omoks that began in 2007 continued throughout the review by the B.C. Utilities Commission, which received final submissions before Hydro announced the benefit agreement this weekend.
The terms were not released and were submitted to the utility commission on condition of confidentiality.
Hydro says only that the deal involves training and education funds for the Island First Nation, and economic development opportunities related to construction.
Aboriginal Relations Minister Ida Chong says such agreements brings certainty to important projects, and foster economic independence for First Nations.