**Author details**

processes proceeding in the reservoir resulted in the changes of physico-chemical properties

According to the guidelines of monitoring programme of lakes, the Turawa reservoir is characterized by moderate susceptibility for anthropopressure according to morphometric, hydrological and basin characteristics. However, the water of the reservoir could have been

According to the qualitative classification of surface water, the reservoir was classified as unsatisfying (class IV) or bad (class V) with respect to oxygen-related parameters (BOD5 and CODMn,), total organic carbon, microbiological parameters and also to the concentration of

In 2004–2006, due to strong eutrophication the following physico-chemical parameters of water worsened: colour, odour, oxygen saturation, transparency, pH, BOD5 and CODMn. Positive tendency of decreasing water hardness and concentrations of calcium, magnesium and

One of the largest threats of ecological status of the reservoir was water eutrophication which threatens ecosystem operation. The most important threats were oxygen deficit in deep areas of the reservoir which is dangerous for aerobic organisms, oxygen oversaturation of epilimnion, decrease in water transparency, pH increase, accumulation of organic matter, reservoir overgrowing, deterioration of taste and smell, and release of phosphorous compounds in anaerobic conditions. Progressing degradation of aquatic environment decreases the usable value of water, lowers the aesthetics of the environment and management of all the water

Deteriorating ecological status of the Turawa reservoir was required to take immediate comprehensive measures to prevent it from total degradation. Remedial propositions were as

**•** Proper management of solid wastes and wastewater and building sewage system around

**•** Reduction of runoff of nutrients out of the catchment to the reservoir (building of wastewater

After 10 years, the physico-chemical parameters are being measured again to assess the results

**•** Decreasing the content of phosphorous and heavy metals in bottom sediments.

classified as the third class of purity, that is, as water strongly polluted.

heavy metals such as lead and cadmium.

sulphates took place.

bodies.

follows:

water body.

treatment plant).

of remedial actions.

**•** Increase in year average water table elevation.

**•** Reducing fluctuations of water table level.

**•** Removal of bottom sediments.

of water.

398 Water Quality

Marek Ruman1\*, Żaneta Polkowska2 and Bogdan Zygmunt2

\*Address all correspondence to: marek.ruman@us.edu.pl

1 Faculty of Earth Sciences, KNOW (Leading National Research Centre) University of Silesia, Sosnowiec, Poland

2 Department of Analytical Chemistry, Faculty of Chemistry, Gdansk University of Technology, Gdańsk, Poland
