**6. Discussion**

202 Environmental Monitoring

Natural and anthropogenic processes take place in the basins of Prespa and Vegoritis lakes and these have an impact on the water resources of the basins. The catchments of the three lakes have been described by the GIS based analysis of "Corine Land Cover Classification" Figure 17-D. MERIS data has been used for Corine land cover map updating because of their improved temporal resolution. Burnt areas due to the 2007 forest fires are detected and

Surface mining takes place in Vegoritis lake basin with negative impacts of mining on the water resources, both surface and groundwater, which occur at various stages of the life cycle of the mines and even after their closure: 1.From the mining process itself, 2. From dewatering activities which are undertaken to make mining possible. 3. During the flooding of workings after extraction has ceased 4. By discharge of untreated waters after flooding is complete. Anthropogenic factors seem to play a key role on the deterioration of the water resources of the region. Integrated Earth Observation / GIS techniques help to monitor changes in lake basins and can cover specific water management requirements, Table 2, Figure 17.

> Implementation is suffering from problems like lack of information,

Figure 17\_B shows the effect of Devolli river diversion to Micro Prespa lake.

Figure 17 C shows the effect of surface mining in the Vegoritis lake basin.

Land cover changes due to forest fires,

The total 550 agricultural cooperatives were converted to 467,000 small holder farms. These land management practices could have driven or intensified different water usage across Albania that would have influenced hydrologic lake water balances..Figure 17, A1 & A2

Agriculture influence both the quantitative / qualitative characteristics of the lakes

insufficient data.

Figure 17 D

**Anthropogenic Impact Comments** 

First aggrement 1959- 2nd 2000 Prespa Park 2/2/2010, Petersberg Process (1998), Athens Declaration Process Water Convention 1992, Karipsiadis2008

Diverson of Aghios Germanos (1936) Diversion of Devolli river (mid-70's) It has deposited about 1.2 million m3 of alluvium in the shores of Micro Prespa Lake. Sluice gates controlling flow of waters from Micro to Macro Prespa lake (2004).

The environmental effects of the extraction stage: Surface disturbance, and the increased amount of sediments transported to the lake.

Multitemporal changes of the surface of

the land was redistributed in Albania.

Irrigation schemes / pumping stations were created during the period 1950-1980, and occur on mainly flat, or gently sloping

Table 2. Selected natural / anthropogenic impacts on the water resources of lakes

lakes 1972-2009 period.

Social changes After the fall of the Eastern Block regimes

and river terrace

mapped on the MERIS data.

Transnational treaties

Infrastructures

Mining

Land cover changes

Agriculture

Monitoring of the lake ecosystems is of paramount importance for the overall development of a region. Remote sensing provides valuable information concerning different hydrological parameters of interest to a lake assessment project. Monitoring is supported due to the multi-temporal character of the data. Temporal changes for the last 30 years can be analyzed with the use of satellite imagery. Processing techniques that have been applied include integrated image processing / GIS vector data techniques. Satellite data generate GIS database information required for hydrological studies and the application of models. Neural network algorithms are quite effective for the satellite data classification. Generated database can be used to assess changes that are taking place in the lakes and its surrounding environment. The areal extent of the lakes has been mapped accurately in all cases. Using the adopted methodology various parameters concerning the lakes and their basins can be extracted related to the description of catchments, surface area, water-level, hydrogeology and water quality characteristics of the lakes.

Water quality parameters of the lakes can be retrieved from remote sensing. Peristrophic movements (gyres) can be clearly identified in the time series images, both in the optical and thermal bands of the Landsat satellite system for the Macro Prespa lake. Understanding the naturally occurring mixing processes in the lake aids in determining the ultimate fate of pollutants, and supports the application of good management strategies and practice. The high spatial resolution of the satellite images allow the surface currents and general circulation in lakes to be accurately identified using the multi-temporal imagery. This can assist in monitoring the clarity and general water quality of lakes. ENVISAT MERIS satellite data have been used for the assessment of spatio-temporal variability of selected water quality parameters like dispersion of suspended solids and chlorophyll concentration. Deterioration of water quantity and quality parameters is interpreted for both Macro Prespa and Vegoritis lakes. It is indicated that satellite monitoring is a viable alternative for spatiotemporal monitoring purposes of lake ecosystems. However, technology alone is insufficient to resolve conflicts among competing water uses. A more useful approach is to have specialists to support decision makers by making available to them the use of data and techniques.
