FE586 Long term changes of hydrologic regime and aquatic chemistry in inland waters of Latvia
Frisk Tom, Kļaviņš Māris , Rodinov Valery, Kokorīte Ilga and Briede Agrita
The study of changes in river discharge is important for development of efficient water resource management systems, as well as in development and validation of climate change impact models.
At the same time the studies of hydrological regime are extremely important and numerous studies are done worldwide. However, considering the situation in Latvia, there are very few
studies, unless their importance may be high considering the local conditions and acute need of better understanding the processes affecting inland waters.
This report deals with the hydrological regime of rivers and their long-term changes in Latvia in comparison with those in Finland and other neighbouring countries. Also basic factors influencing
river discharge regime such as soil types, climate patterns, geological structures were analysed and their possible impact on river discharge regime were studied.
Quite evident periodic oscillations of discharge intensity, and low- and high-water flow years were considered. A main frequency of about 20 and 13 years was estimated for the studied rivers.
Aquatic chemistry has been found to be controlled both by land-use pattern, human impact and hydrological factors, but in varying extent for different water bodies. The possible sources of the
major water ingredients, and their relative contributions to loads to waters were identified.
Tom Frisk, Tel. +358 3 2420111, Pirkanmaa regional environment centre