Long-term limnological research in a quarry lake of the Po River, Italy

In recent years, many artificiallakes have been constructed in the Po River flood plain and along its triburaries, as a result of sand and gravel quarrying. However, only in a few cases have the public agencies responsible for environmental policies established regulations based on ecological criteria for rhe excavation and reclamation of rhe perifluvial areas. Consequently, most of the newly formed lakes are characterised by unsatisfactory water qualiry (VIAROLI er al. 1996, BoDINI er al. 2000). A limnological study on a quarry lake (Isola Giarola) of rhe flood plain of the Po River was started in 1991. The lake receives periodic flood waters which introduce high nutrient loads. The recovery capacity of the ecosystem following river inflows has been assessed through the analysis of trophic status parameters and the zooplankton communiry seasonal succession patterns over a l 0-year period. This long-term research aims to establish scientifically based guidelines for the construction and management of quarry lakes in rhe Po River basin, with rhe major objectives of ensuring acceptable water qualiry standards and preserving the hydraulic and biological functions of rhese aquatic environments.