Hidrológiai Közlöny, 2017 (97. évfolyam)
2017 / 3. szám - MANAGING WATER QUALITY (ONGOING PROJECTS AND FUTURE CHALLENGES) - Rehák, Štefan - Vranovská, Andrea - Adam, Štefan - Kopčová, Ľubica: Hydrological balance of water resources for agriculture in the Slovakian part of the Danube Region
55 Stefan Rehák: Hydrological balance of water resources for agriculture in the Slovakian part of the Danube Region Area I. Danube Lowland - South is bordered by the isoline of relative evapotranspiration 0.6. It is the driest area in Slovakia with the highest intensity of agricultural production. Area II. Danube Lowland - North is located between Bratislava and Sahy in the territory between the isolines of relative evapotranspiration 0.6 to 0.7. It is a slightly dry area where densely sown crops should prevail in the future. Area III. Záhorie Lowland is a slightly dry area bordered by the isoline of relative evapotranspiration 0.7 and the River MoravscArea IV. Southern Slovakia Basin is a slightly dry area bordered by the isoline of relative evapotranspiration 0.7 from Sahy to Lenár- tovce and the border with Hungary. Area V. Eastern Slovakia Lowland is a slightly dry area bordered by the isoline of relative evapotranspiration 0.7 and Hungary and Ukraine. Area VI. Kosice Basin is an important areafor growing fruit and vegetables for the urban population, and therefore there is the potential for the development of micro-irrigation. The above-mentioned lowland areas of Slovakia are typical for annual precipitation totals being lower than annual totals of potential evapotranspiration. Increasing the difference between precipitation totals and the potential evapotranspiration totals makes the area more sensitive to droughts It means that the dependence of water balance components of the territory on climate change impact is considerable in complicated soil conditions. On the basis of submitted results (Sátor et al. 2007), it is possible to state that the occurrence of extremely long time periods without precipitation has a dominant impact on the origin of soil drought in agricultural production areas during the vegetation period in the process of retrospective monitoring and assessment of the periods without precipitation. Periods without precipitation are a significant phenomenon of climate change Results show that it is impossible to find any regular occurrence of no precipitation periods; they are of stochastic nature. In Europe, with the consideration to climate change, irrigation has stopped to be assessed and designed as an intensifying factor of agricultural production but it is considered as a stabilizing factor of sustainable agricultural development. It is presumed that the extension of irrigation systems in the main irrigation areas will be a primary adaptation measure to mitigate the negative impact of climate change. The extension of irrigation to almost 500 thousand ha will create a high pressure on available water resources. The total irrigation water demand is expected to increase by 115% and irrigation water consumption by approximately 75% by the year 2075 {Table 1). Table 1. Current status and expected development of irrigation in Slovakia till 2075 Irrigation area Irrigation size [thousand ha] 2005 2010 2030 2075 i. 177 160 255 325 ii. 76 60 70 75 in. 22 15 25 35 IV. 18 8 25 35 V. 27 7 25 30 VI. 1 0 0 0 Total 321 250 400 500 PROGNOSIS OF IRRIGATION WATER DEMAND ACCORDING TO SCENARIOS OF THE CLIMATE CHANGE FOR THE YEARS 2030 AND 2075 A prognosis of irrigation water demand is made for each moisture deficit area in Slovakia. There were simulated amounts of irrigation water demand, prognosis of irrigation size for these areas and time horizons of the years 2010 (referential/verification year), 2030 and 2075 (Table 2). Table 2. Prognosis of irrigation water demand according to the scenario CCCM (Takác in Alena et al. 2005) Area Horizon 2010 Horizon 2030 Horizon 2075 m3 ha-1 1000 ha million m3 m-’.ha'1 1000 ha million m3 m3 ha'1 1000 ha million m3 1. 1 380 160 220,8 1 40(1 255 357,0 1 480 325 481,0 II. 1 000 60 60,0 990 70 69,3 1 050 75 78,75 III. 900 15 13,5 950 25 23,75 1 030 35 25,75 IV. 1 090 8 8,75 1 130 25 28,25 1 320 35 46,2 V. 1 020 7 7,15 1 040 25 26,0 1 210 30 36,3 VI. 400 0 0 430 0 0 430 0 0 Total O 1 240 250 310,2 0 1 240 400 504,3 0 1 336 500 668,0 In the next 60 years, the total water demand for irrigation is likely to increase by approximately ! 15%, which will be caused by the increase of the deficit of potential and actual evapotranspiration. The size of necessary irrigation area should be increased by approximately 100% in comparison to the current status (the year 2010). PROGNOSIS OF AVAILABLE WATER RESOURCES FOR IRRIGATION The prognosis of water management balance (Fekete 2013) estimates water demand for irrigation on the basis of the scenario CCCM for the horizons 2010, 2030 and 2075. Water resources are calculated on the basis of natural average monthly discharges with high availability and minimum residue discharges are considered within valid values MQ (Fekete 1985, 1990). The balance is prepared by the assessment of outlet profiles of individual subbasins. Results are declared through the capacity of water resources (discharges). Negative numbers mean the lack of water resources (Table 3, 4 and 5).
