FORSKREF - - Direktoratet for naturforvaltning

SummaryThis report presents results from the annualsurveillance in 1997, 1998 and 1999 in the tworeference catchments Atna in the countiesHedmark/Oppland and Vikedal in Rogaland.Both have been part of the project "Researchandreference-catchments, Forskref" since 1984(Atna) and 1996 (Vikedal).Atna and Vikedal are both nutrient-poor, andestimated staus of eutophication based onbiological observations is "Very good": Qualityclass I. The lover part of Vikedal, is howeverslightly polluted by nutrient salts and organicmatter and ecological status is etimated as"Good": Quality class II. Both catchmnets havelittle buffer-capacity. Vikedal is acidified invarying degree. Reduced sulpuric emmisionshas given reduced sulhuric deposition and theecological status for acidification in Vikedalhas improved since 1990. Atna was neveracidifed.Atna - annual report 1997-1999Annual reports are given for: hydrology,sediment transport, phytoplankton (Atnsjøen),zooplankton (Atnsjøen), periphyton, invertebratesand fishes (Atnsjøen).Vikedal - annual report 1997-1999Annual reports are given for: hydrology,sediment transport, waterchemistry,zooplankton (Fjellgardsvatn, Røyravatn,Botnavatn), periphyton, invertebrates andfishes (Fjellgardsvatn).10