Hydrodynamics of Lake Karhijärvi - An Experimental Study of the Wind Forcing Effects on a shallow, eutrophic lake

1 Preface Studies on hydrodynamics of lakes and wind forcing effect analysis started in the early years of the 1900 (Wedderburn 1912). From the early ‘60, models on water quality were introduced and largely improved in the following years (Imberger 1980) several theory on thermal stratification and seiches depending on wind due to wave generation have been developed. First plankton dynamics and hydrodynamics studies started in the early ’30 (Gran and Braarud, 1935) but only recently full physical processes are considered in biology dynamics of fresh water (Reynolds 1989 and 1994). In the late 1970 eutrophication effects shortly reach a peak that generated a broad and new attention to water environmental problems. The problem of temporal and spatial scale of hydrodynamics and biodynamics is still not totally solved (Legender and Demers 1984) so research is developing in this direction. The present work is to prove once more the complexity and the wide range of subjects that lakes studies involve, and is done with the aim that results of research should be applied by policy makers. In the following pages factors affecting the hydrodynamics of lakes are reviewed and a hydrodynamic model application is conducted on a shallow lake. Possible connections between physical factors and biology aspects are presented in the lasts chapters. Main data were collected during a six months' stage at Pirkanmaan Ympäristökeskus (Environmental Center of Tampere, Ministry of the Environment) in the framework of a more wide restoration project on lake Karahijarvi.