26 2.2 W A T E R Q U A L I T Y I N S L O V E N I A In 2006, the quantitative sampl<strong>in</strong>g of benthic <strong>in</strong>vertebrates and phytobenthos, carried out by sampl<strong>in</strong>g multimicrohabitat types <strong>in</strong> selected water bodies, was carried out <strong>in</strong> <strong>Slovenia</strong> for the first time. The samples were laboratory proceeded (sub-sample sort<strong>in</strong>g and determ<strong>in</strong>ation to required level) us<strong>in</strong>g new national methodology (18, 19, 20). They were evaluated accord<strong>in</strong>g to the expert groundwork for the assessment of the organic pollution of rivers by us<strong>in</strong>g an adapted saprobic <strong>in</strong>dex based on of benthic <strong>in</strong>vertebrates and phytobenthos (21, 22). Only 22 selected rivers were analysed. Sampl<strong>in</strong>g and further laboratory proceed<strong>in</strong>gs of 37 monitor<strong>in</strong>g sites showed that, accord<strong>in</strong>g to quality assessment based on phytobenthos, 43% of monitor<strong>in</strong>g sites had a high status, 32% a good status, 22% a moderate status and 3% had a poor quality status. The results of benthic <strong>in</strong>vertebrates sampl<strong>in</strong>g and analysis, however, showed that 57% of monitor<strong>in</strong>g sites had a high status, 27% a good status, 11% a moderate status, 3% a poor status and 3% had a bad quality status. It should be emphasized that this assessment has been made based on only two biological quality elements, for only one pressure (organic pollution) and at selected monitor<strong>in</strong>g sites. In the follow<strong>in</strong>g years, a classification of the ecological status will be presented, represent<strong>in</strong>g the measurement of the alteration of the ecosystem’s structure and function<strong>in</strong>g from the natural state, i.e. the state where there are no, or only very m<strong>in</strong>or human impact. The assessment of the ecological status is based on biological quality elements (phytoplankton, phytobenthos and macrophytes, fish and benthic <strong>in</strong>vertebrates) and on hydromorphological, chemical and physico-chemical elements support<strong>in</strong>g the biological elements. The assessment system will enable a dist<strong>in</strong>ction between five classes of ecological status: “high”, “good”, “moderate”, “poor” and “bad”. S<strong>in</strong>ce the start<strong>in</strong>g po<strong>in</strong>ts or reference conditions of water bodies are different, a type-specific approach will be used whereby the waters are classified <strong>in</strong>to types accord<strong>in</strong>g to their natural characteristics and then reference conditions are def<strong>in</strong>ed for each type (27, 28, 29, 30). The evaluation of the ecological status of rivers <strong>in</strong> <strong>Slovenia</strong> will be possible only when assessment methods for all biological quality elements and different pressures are prepared. <strong>Quality</strong> of Lakes With <strong>Slovenia</strong>’s association with the European Union, the <strong>Water</strong> Framework Directive (1) has become the b<strong>in</strong>d<strong>in</strong>g and key document <strong>in</strong> the field of water management and has also <strong>in</strong>fluenced changes <strong>in</strong> the monitor<strong>in</strong>g of lake quality. The period from 2003 to 2006 was actually a transitional period for the implementation of the <strong>Water</strong> Framework Directive, which has brought important changes <strong>in</strong> lake sampl<strong>in</strong>g and, most of all, a new, <strong>in</strong>tegrated approach for the assessment of ecological status, which could not be used <strong>in</strong> that period due to the assessment methods still <strong>in</strong> the course of preparation. Until 2002, national monitor<strong>in</strong>g of lake quality was carried out only on Lake Bled, Lake Boh<strong>in</strong>j and Cerknica Lake. S<strong>in</strong>ce 2003, due to the requirements of the <strong>Water</strong> Framework Directive, the monitor<strong>in</strong>g has also <strong>in</strong>cluded artificial lake, reservoirs and river accumulations of an area larger than 0.5 km2 (31, 32), which are accord<strong>in</strong>g to the Rules of identification and classification of surface water bodies (15) def<strong>in</strong>ed as water bodies (Map 3, Table 5). These are the follow<strong>in</strong>g: Lake Bled, Lake Boh<strong>in</strong>j, Velenje Lake, Šmart<strong>in</strong>sko Lake, Slivniško Lake, Perniško Lake, Gajševsko Lake and Ledavsko Lake, the reservoirs of Klivnik, Molja and Vogršček, as well as the river accumulations of Moste, Mavčiče, Vrhovo and Ptuj Lake. Monitor<strong>in</strong>g was due to a high rate of flow not carried out only <strong>in</strong> Ormož Lake, but it was nevertheless performed as part of the monitor<strong>in</strong>g programme of rivers. In the river accumulations of Mavčiče, Vrhovo and Ptuj Lake, monitor<strong>in</strong>g was carried out only <strong>in</strong> the event of the ‘bloom<strong>in</strong>g’ of phytoplankton, which is characteristic of the dry season when the rate of flow <strong>in</strong> river accumulation is at its lowest and the accumulations are given the status of stand<strong>in</strong>g water bodies. The <strong>in</strong>termittent Cerknica Lake, which does not have any common characteristics with permanent lakes, was <strong>in</strong>cluded <strong>in</strong> monitor<strong>in</strong>g of lakes <strong>in</strong> the years 1993 to 2005. S<strong>in</strong>ce there are Karst Rivers, which dur<strong>in</strong>g high waters tend to flood the Cerknica field, the sampl<strong>in</strong>g and assess<strong>in</strong>g the lake were carried out <strong>in</strong> accordance with the criteria for rivers, and the status of Cerknica Lake is also presented <strong>in</strong> the data for rivers.
Lake Boh<strong>in</strong>j Table 5: List of water bodies <strong>in</strong> <strong>Slovenia</strong> where monitor<strong>in</strong>g of lakes is carried out Name <strong>Water</strong> body type Sub - bas<strong>in</strong> Surface area (km 2 ) Volume (m 3 10 6 ) S U R F A C E W A T E R S Depth (m) Lake Bled J Sava 1.43 25.7 31 max. Lake Boh<strong>in</strong>j J Sava 3.28 92.5 45 max. Cerknica Lake V Sava > 24 do 76 >3 mean. Šmart<strong>in</strong>sko Lake kMPVT Sav<strong>in</strong>ja 1.07 6.5 6 mean. Slivniško Lake kMPVT Voglajna 0.84 4.0 5 mean. Ledavsko Lake kMPVT Mura 2.18 5.7 >3 mean. Perniško Lake kMPVT Pesnica 1.23 3.4
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