DANUBE

Thanks to the Water Research center in Swindon UK, the model MINDER was shared, modified, improved and tested at the Slovak Environmental Agency over the river HRON , as the significant DANUBE contributary. The potential eutrophication risk in the rivers and water bodies was modeled previously in the ArcInfo GRID environment. All data preprocessing, GIS implementation, modeling and cartographic outputs described briefly by the enclosed flow chart were done by:

1. ArcInfo
2. EASI-PACE
3. ArcView
4. Idrisi
5. PowerPoint

The area of the river HRON watercachment was selected as the appropriate landscape for the modeling in summer 1995. This area has representative characteristics that may occure in such modeling over the Slovakia territory (see details in table and the location in the schematic maps).

   NAME of the river HRON   AREA of the watershed ............... 5464.54 km2 
          Length of the river ..................... 290.0 km   
          Average rate of flow .................... 56.0 m3.s-1 

   FLOOD water per 1 year................... 315 m3.s-1               
   per 10 years ................ 600 m3.s-1               
   per 100 years ............... 790 m3.s-1 

   ALTITUDE and location of the spring......934.0 m a.s.l. Central Slovakia 
                         of the estuary .... 102.9 m a.s.l. Danube 
   SLOPE of the river ...................... 3.29 %.         
         Right side tributaries from altitudes ......... 800-1300 m a.s.l. 
         Left  side tributaries from altitudes ......... 600-1200 m a.s.l. 
   

   PRECIPITATION        average summary for period 1931-1960        
         lowland areas ......................  600 - 700 mm year-1        
         valleys ............................  700 - 900 mm year-1        
         mountains .......................... 1000 - 1200 mm year-1

   EVAPORATION average value per year        
         lowlands ...........................  500 - 600 mm year-1        
         valleys ............................. 400 - 500 mm year-1        
         mountain slopes and tops ........... approx. 400mm year-1 

   RUNOFF 
         at lowlands ........................   1.5 -  5.0 l.s-1.km-2        
         in valleys ..........................  5.0 - 10.0 l.s-1.km-2        
         from mountains up to 1300 m ........  10.0 - 15.0 l.s-1.km-2        
         from mountains up to 2000 m ........  20.0 - 30.0 l.s-1.km-2

The project has the following six main stages and there were completed in approx. 14 months period.

1. project preparement
2. ensurance of data, training and technical background
3. data integration and GIS implementation
4. modeling, calibration and statistical analysis
5. map compositions and DEMO processing
6. final documentation

The hydrologicaly corrected DEM was required by the model. Due to this the former DTM based on the military topomaps 1:25 000 in raster 100x100m (processed in EASI-PACE) was enhanced by the following inputs:

• triangulation and nivelation points
• river flow axes with stream direction
• lakes boundaries and altitudes

Before the project startup the following potential risks in data availability relevant to the CORINE landcover were mentioned : changes in land ownership -> changes in real-estate and landuse, privatization in industry -> changes in management and/or production character, lawmaking process -> changes in inventory and archives and monitoring. Datasets should be synchronous with the time horizon of LANDSAT TM scenes used in CORINE Landcover

The synchronization was determined by date of the Northern LANDSAT TM scene 188-26 because it covers approx. 90% of the river Hron watercatchment. Besides that the datasets should be within the continuous period of 24 month required for the modeling stage. Two secondary mapping were linked to the CORINE thematic layer : root depths and export coefficients used in the modeling stage.
Phosphorus export coefficients were involved into the modeling as an assessment of the

1. point sources (industry, farms, Water Treatment Plants)
2. non-point sources (landcover, settlements)

The enclosed doughnut chart is just theoretical image (the modeling result) of relationship between area and Ptotal export/load caused by the landcover/landuse. Assessment of the landcover export coefficients should be based more on the regional practices used in the agriculture, farming, landscape protection and just after detail statistical analysis and ground truth verification stage some conclusions might be done.

The model shows the possibility of development reliable tool for the eutrophication risk control, even the calibration was very limited by lack of the calibration profiles (just 4 profiles were synchronized, see enclosed P, Q graphs and trends within the summer months ). Actual availability of appropriate calibration stations is challenge for the next model improvement over the Hron watercatchment, but the landcover should be updated due to the changes in land ownership ( more heterogenous character ) and due to the changes in management and/or production character caused by the privatization in Slovak industry.
The project and its stages is documented by report, brief statistical tables, graphs and 24 maps, that may be plotted up to the scale 1:100 000 according to their resolution and accuracy.

The last Ptotal year averages (1991-95) appears decreasing trend in the main river Hron, but the alarm pointers on its tributaries previously in the agricultural and urban lowland should be stimulating (see window of the final map). Further development of the non-point pollution sources model based on the RS & GIS is necessary along with the model implementation into the standard control mechanism supported by legislation and international conventions. The timehorizon 1995-97 (with enough calibration datasets, but new CORINE interpretation ) should be processed by the model and after this there should be enough arguments with detail statistical analysis for the model application over the different Slovak watercatchments.
Professional help of the WRc coordinator, international cooperation and more than one year of work at the SEA was done to fulfill the main project objectives. The 1st aim of the EC, to implement the CORINE results, was successfully completed. The 2nd and 3rd aims of the participants and WRc were partially completed, because the model development is like 'neverending story' and development of relevant technologies and human knowledge in this multidisciplinar field is still an open system. Results put positive feedback into this system and helped in its progress. Hope the final workshop will confirm this opinion.

Nada Machkova et al.
Slovak Environmental Agency
Tajovskeho 28
975 90 Banska Bystrica, Slovakia
machkova@sun.sazp.sk
http://www.sazp.sk