Water discharge at the outlet of the Ekso into Eidsfjord was halved after the big hydropower development in the mountainous area between Modalen and Eksingedalen and further southward toward Evanger in the 1960s, 70s and 80s. In an attempt to amend the changed environmental conditions in the waterway the developer built 35 small dams in the river.
In the late 1800s, Ekso was known among the nobility in England as having among the best salmon rivers. In summer the Lords could haul in big fish of up to 25 kg. In return, the townsfolk were paid for fishing rights, lodging and local assistance.