EVALUATING HABITAT RESTORATION OF RIVERS CHANNELIZED FOR LOG TRANSPORT - A CASE-STUDY OF THE RIVER KUTINJOKI, NORTHERN FINLAND

During the last decade, several extensive river restoration projects h ave been started in Finland aimed at restoring the original habitat st ructure in rivers channelized for log transport in the 1950's-1960's. The main goal of the restoration is to increase the diversity of the r iverine environment and to enhance fish habitats by rearranging the su bstrate in the river bottom. Boulder dams employed in the river Kutinj oki increased the diversity and patchiness of available depths, veloci ties and dominant substrate size-classes making the rapids spatially m ore complex. The successive riffle - pool - structure at the study sit es was clearly visible after the restoration, in contrast to the more or less homogenous pre-restoration flow pattern. The restoration proce dure seems to favour 1+ or older trout. For the planning and evaluatio n of fish habitat enhancement of this kind, it is highly advisable to employ the modelling of the hydro-physical conditions at the scale rel evant to the fish and to include in the analysis the fish habitat pref erences.