Communication channels and powerful natural elements, the rivers in the area were greatly explored and used by settlers who then in turn drew sustenance from them. The first occupants of the small parishes around Lac-Saint-Jean used the many waterfalls to build sawmills, flour mills and mills for carding wool.
It was in the sawmills where wood was cut and then sent to factories which became pulp or paper at the end of the full process. Given the lack of wood transportation, the log drive was practiced forcing sawmills to operate near high-volume waterways. The same applied to the plants, like the Lake St. John Power and Paper of Dolbeau which Wallberg positioned at the edge of the Mistassini River.
The full potential of the rivers often resulted in hydro-electric power projects. Furthermore, Wallberg someday wished to build a dam on the Mistassini. He even purchased a waterfall belonging to the Trappists for $10,000, but the project fell through after his death.
For the Trappist Fathers of Mistassini, the Mistassini and Mistassibi rivers were used as bridges, in winter, when people traveled over the frozen rives on horseback. Huge chunks of ice were also harvested until 1936, which allowed food to be frozen.
However, the presence of the waterfalls was also a source of problems, when we think of bad floods, flooding, mosquitoes and drownings, for example.