Korišćenjem raspoloživih kapaciteta numeričkog modeliranja (uzimajući u obzir nastale prioritete u rešavanju plavljenja unutrašnjim vodama, odnosno uključivanje područja pogodnih za zadržavanje voda) na osnovu sledećih razmišljanja se može predložiti preobražaj upravljanja vodama (Kozák 2013, 2016):
• budućim merama treba poboljšati sigurnost naselja i nastanjenih područja od unutrašnjih voda.
• Za usporavanje procesa sakupljanja voda treba se truditi za primenu zatvaranja oticanja prvenstveno u uvalama na višim delovima.
• Zadržavanje voda celishodno bi bilo rešiti uz kanale na područjima sa odgovara-jućim morfološkim svojstvima i načinom korišćenja zemljišta.
• U toku izbora površina za zadržavanje voda celishodno bi bilo odabrati one površine koje ne dovode do povećanja rizika na unutrašnjim površinama i to odabirom terena koji su izuzeti iz poljoprivredne obrade, ili su poljane i pašnjaci.
• Od vlasnika treba pribaviti saglasnost za terene koji su pogodni za zadržavanje voda.
• Prilikom projektovanja zadržavanja voda treba izbegavati nastajanje većih dubina.
• Pri eksploataciji zadržanih količina vode treba uzeti u obzir da u letnjem periodu isparavanje može dostići i 10-15 mm na dan.
• Razvojem poveznog kanala potoka Gat i jezero Feher biće u stanju odvođenja većih količina (~3,1 m3/s) voda, čime će se smanjiti rizik od unutrašnjih voda.
Instead of a foreword
“This study could not have been produced without…” – a frequent and compulsory set of words in project documents, followed usually by the name of an institute, sponsor or research program which provided funding for the work. However, the person behind is rarely acknowledged. The person who delivers the project idea, who adheres the partnership through never-ending negotiations, who motivates successfully numerous colleagues to work together in an international environment and to utilise scientific results for solving real life problems. The person who coordinates project implementa-tion from the start till the end, participates on each meeting and event, if needed leads the discussion or gives a presentation, but if needed stays in the background and gives space for younger colleagues, and through the joint work lays down the fundaments of a new project by the way. The person without whom not only this project and its closing document but many others could not have been realised at all.
Gábor Mezősi, Professor of the Department of Physical Geography and Geoinfor-matics, University of Szeged is a Person of that kind. Over his more than 40 year long career in education, research and science management he has also undertaken a key role in the organisation and implementation of countless national and international projects. Such way he successfully developed project based collaboration among others with several departments of the University of Novi Sad and Voda Vojvodina, and meanwhile also deepened cooperation with the Lower Tisza Water Directorate by bringing new scientific contents to the joint work. This book, opening again new opportunities for further cooperation, is a clear manifestation of his constant and devoted efforts, for which we would like to express our deepest gratitude.
Thank you!
The Project Team
1. Introduction
Viktória Blanka; Zsuzsanna Ladányi; Gábor Mezősi; János Rakonczai
One of the most important environmental problems nowadays is climate change, the negative effects of which have an impact on the whole planet. In the last 100 years the average temperature of the Earth increased by +0.7°C and undesirable changes occurred also in case of precipitation, as long periods without rainfall and extreme pre-cipitation events became more frequent in large parts of the temperate zones on both hemispheres (OMSZ 2019). The climate change has a considerable impact on the low-land areas of southeast Hungary (Csongrád and Bács-Kiskun counties) and Vojvodina, including the study area (Fig 1.). Due to the climate change and the natural geographic conditions, the water supply of the region is showing extreme variation, the area suf-fers from both drought (Fiala et al. 2014) and inland excess water (Bozán et al. 2013) – these can take turns, and occur in consecutive years or even in the same year. This is the reason why the research and geographical observation of the problems related to climate change and hydrological extremes is very important in the region, which started decades ago (Kovács 2007, Ladányi et al. 2011a, Rakonczai 2011).
Figure 1.1 Location of the study area
The majority of this area is lowland, where the mean annual temperature is around 11°C and the annual precipitation is 500-600 mm. The highest mean temperature occurs in July, typically between 21°C and 23°C, while the rainfall is around 300 mm in the summer half of the year (Smailagic et al. 2013, OMSZ 2019). Examining the cli-mate change trends of the last decades reveals that the temperature has been rising and the precipitation level has been slightly decreasing (Blanka et al. 2013; Spinoni
et al. 2013), resulting in a 20-30 mm yearly precipitation shortage in the area. It was also observed that the frequency of extreme weather conditions’ occurrence has also changed. Years drier than the average have become more frequent, and the distribu-tion of the rainfall is turning less and less favourable, as beside the long dry periods, extreme precipitation events occur especially in the summer causing an increase in the runoff proportion of the valuable water resources (Mezősi et al. 2016).
In the examined area the most important rivers are the Danube, the Tisza/Tisa River, the Maros River, and the Tamis River; besides these, most of the surface waterflows are artificial canals (Fig 2). Parallel to the changes in the climate, the spa-tial and temporal variability of the surface water volumes were also observed (Kiss and Blanka 2012, Sipos 2006). This not only generates a growing flood (e.g. on the Danube in 2013) and inland excess water hazard, but also longer periods of water shortage that contribute to a growing economic, social and environmental problem for the study area. In general it can be stated that the annual water balance of the region shows a negative trend, as regards both surface and ground waters. In a large part of the year the surface runoff is insignificant, which greatly contributes to the climate sensitivity of the area, and to the growing water stress that is likely to occur in the future.
Figure 1.2 Waterflows, soil types (FAO 19895) (Be: Eutric Cambisol, Bh: Humic Cambisol, Ck: Calcic Chernozem; Ckcb: Vermi-Calcaro-Calcic Chern.; Ge: Eutric Gleysol, Gm: Mollic Gleysol ; Hc: Calcaric Phaeozem; Hcb: Vermi-Calcaric Phaeozem, Hg: Gleyic Phaeozem; Hh: Haplic Phaeozem;; Jc: Calcaric Fluvisol; Jcg: Gleyo-Calcaric Fluvisol; Qc: Cambic Arenosol; Qcc: Calcaro-Cambic Arenosol; Sm: Mollic Solonetz; So: Orthic Solonetz; Vp: Pellic Vertisol; Zg Gleyic Solonchak; Zo Orthic Solonchak) and land use (Corine 2018) (1: Artificial surfaces; 2: Agricultural areas; 3: Forests and semi natural areas;
4: Water bodies; 5: Wetlands) of the study area
The study area is diverse in terms of soil type, physical properties and soil moisture regime of the soils (Fig 2b). Chernozem soil and its different variations dominate the area; their crumbly structure, resulting from the advantageous soil formation processes ensures good water and nutrient management conditions for agricultural production. Sandy soils (blown sand, humic sandy soils and chernozem-type sandy
soils) can also be found in considerable proportions; these soils having unfavoura-ble moisture regime due to huge water infiltration and weak water-holding capacity.
Meadow soils are also common in the region, which have medium or weak infiltra-tion and good water-holding capacity.
The land cover and land use of the area is dominated by agricultural lands (Fig 2c).
In the last 200 years large areas of land became used for farming purposes, there-fore the proportion of agricultural land is high, and the natural vegetation remained only in relatively small areas. Even in these areas, where the natural vegetation sur-vived, unfavourable processes can be observed, because the climate change of the last few decades and human activities resulted in natural wetland habitats starting to dry out, and this process is accompanied by the degradation and transformation of the vegetation (Rakonczai et al. 2014).
Extreme water balance situations cause serious socio-economic and environ-mental damages, and they also generate major water management conflicts. In the periods of inland access water inundations, the drainage practices of excess water generate conflicts, in both populated areas and outside of towns and villages, while in the drought periods the limited availability of water and water use practices cause problems. Several problems are related to the irrigation of agricultural land, because in spite of the relatively dense canal network – in the present conditions – these canals are hardly suitable for irrigation purposes. Due to the lack of surface waters that can be used for irrigation, at the time of dry periods/droughts farmers use water from underground resources, which just makes the problem of decreas-ing groundwater resources worse, which are already decreasdecreas-ing because of the climate change. Another problem is that water retention and the utilisation of waste water produced in the area is still at an initial phase, therefore the water resources that are generated aren’t utilised adequately (Rakonczai et al. 2014).
Mitigating the negative effects of drought and inland excess water, and manag-ing land use and water resource related problems are among the most important complex environmental problems to be solved in the region. Effective management requires collecting accurate and timely information that describes the current water balance situations and a better understanding and quantification of negative effects and risks, which can provide fundamental information for planning efficient inter-ventions. It is essential to implement the planning of water management in a (small) catchment level, and it is also important to ensure the efficient cooperation of the stakeholders in both planning and implementation.
The project that provides the background for this book and the presented devel-opments seek to contribute to managing the problems introduced, and to planning water resource management more efficiently: by developing regional monitoring methods and collecting information to observe the formation of drought and inland excess water (chapters 2, 3 and 4), by evaluating the risks and the damages caused (chapters 5 and 6), and by reconsidering the operational management of the canal network, based on much more detailed and accurate data than before. For devel-oping improvement ideas for the operational management of the canals, detailed examinations were performed in two pilot areas, the catchments of Curug-Zabalj (Serbia, chapter 7) and Dong-ér (Hungary, chapter 8) (Fig 1).
2. High precision mapping and monitoring of inland excess water inundations
Zalán Tobak; Boudewijn van Leeuwen; Ferenc Kovács; József Szatmári
Introduction
In rainy periods, in endorheic areas excess water that does not disappear through infiltration or evapotranspiration, or upwelling groundwater fed by run-off from under the surface from areas located higher, manifests on the surface in the form of shallow inundations. This temporarily occurring inland excess water is the source of serious economic, environmental and social problems on the plains of the Carpathian Basin.
The mapping of inland excess waters is very important from 3 aspects: (1) it helps to understand the relationship between factors that contribute to the accumulation of inland excess water, (2) knowing the location and size of inland excess water inun-dations makes it possible to do operative work for drainage purposes and for pre-venting further damage, and (3) the location, size and scale of future inland excess water inundations can be forecasted, which can be of help in preventive processes (Szatmári and van Leeuwen, 2013).
Four general methods are used for mapping and monitoring inland excess water:
(1) field survey takes a lot of time, there can be many mistakes, it costs a lot of money and the resulting maps are often inaccurate. (2) By integrating the factors that contribute to the accumulation of inland excess water into a geographic infor-mation system (GIS), hazard maps can be made, but the inundations that have already occurred can’t be determined by using this method (Pálfai, 2003; Bozán et al., 2005; Bozán et al., 2009; Pásztor et al., 2014). (3) Complex models that describe the hydrological process of inland excess water formation require a large volume of data, therefore they can’t be used effectively on a regional scale. (4) Data collected using satellite or remote sensing technology provide information about a large area, paired with processing and evaluation methods that can be automated, offering an optimal solution for the regional level, operational mapping of inland excess water.
As part of utilising the latter approach, in the last 30 years several research pro-jects were realised using aerial photography (Licskó et al., 1987; Rakonczai et al., 2003; van Leeuwen et al., 2012), multispectral satellite images (Csornai et al., 2000;
Rakonczai et al., 2001; Mucsi and Henits, 2010, van Leeuwen et al., 2013) and hyper-spectral data (Csendes and Mucsi, 2016). In addition to passive, optical sensors, the applicability of active, radar data has also been proven (Csornai et al., 2000; Csekő, 2003; Gálya et al., 2016, Gulácsi and Kovács, 2019).
It was of great help in the operative use of satellite images that systems of Earth observation satellites had been built, with adequate spatial resolution (min. 10-30 m) and better revisit periods. Within the framework of the European Space Agency’s (ESA) Copernicus programme, the Sentinel satellites launched from 2014 onwards serve the needs of various fields of application, for instance in the form of providing multispectral and radar images (Malenovský et al., 2012). The active sensors of the Sentinel 1A and 1B satellites provide radar data regardless of the weather conditions, while the Sentinel 2A and 2B satellites gather multispectral data 2-3 times a week.
The work process that was developed as part of the Water@Risk project utilises satellite images from Sentinel 1 and Sentinel 2 to produce regional scale inland excess water maps in an operative way, on a weekly basis.