An extensive delta and estuary system has developed where the river enters Ogoki Lake.

The following fish species have been identified in Ogoki River system:[2] In 1943, the Hydro-Electric Power Commission of Ontario diverted a large part of the upper Ogoki to flow into Lake Nipigon and on to the Great Lakes.

This diversion was intended to increase water flow for the Sir Adam Beck Hydroelectric Generating Stations at Niagara Falls, downstream of Lake Erie.

Together with another 3 control dams, this dam raises the water level by about 12 metres (40 ft), thereby creating Ogoki Reservoir (which is 70 kilometres (43 mi) long and covers an area of approximately 150 square kilometres (58 sq mi)).

It also has a number of plant species that are of regional significance, such as the sandbar willow, along the riverbanks, and the ovate spikerush, found on an Ogoki Lake beach.