Mangahao River at Marima Domain

Users should look out for the presence of cyanobacteria/blue green algae (shiny, smooth black or dark green algae that coats stones on the river bed) during low flows as this can be potentially toxic to dogs and humans if consumed. Two dams forming part of the Mangahoa Power Scheme are located in the headwaters and the site has signs posted warning campers thatwater levels can rise quickly if water is spilled from the dams in very wet weather.