Figure 2.

Habitat characteristics at Isterfoss rapids. Solid lines: Mean water temperature in the outflow of Lake Femund (61°56.094′N 11°52.034′E) measured daily in the period 14 August 1984–20 August 2013 (higher values), and in the Atna River (62°00.604′N 9°59.986′E), measured 02 June 1987–21 May 2014. The outflow of Lake Femund is c. 5.3 km upstream from the outflow of Lake Isteren at Isterfoss, and the temperatures at both sites are assumed to be very similar. Dotted line: Mean daily discharge from Isterfoss measured at Lake Galtsjøen (61°53.479′N 11°45.227′E) in the period 26 June 1949–31 December 1983. Data source: Norwegian Water Resources and Energy Directorate