![\"\"](\"https:\/\/www.vtei.cz\/wp-content\/uploads\/2026\/08\/Vyskoc-fig-1.jpg\")
<\/a>\nFig.\u00a01. Methodological framework<\/h6>\n
It can\u00a0be divided into three consecutive stages:<\/p>\n
\n
- \n
- development of\u00a0water demand scenarios, particularly the\u00a0forecasting of\u00a0water abstraction requirements,
\n
\n<\/li>\n - development of\u00a0climate change impact scenarios for hydrological characteristics and identification of\u00a0areas with water deficits,
\n
\n<\/li>\n - assessment of\u00a0the\u00a0balance between water demands and water resources, taking into account the\u00a0existing infrastructure (reservoirs, water transfers, and\u00a0their capacities), followed by an\u00a0assessment of\u00a0water resource security and the\u00a0identification of\u00a0potentially vulnerable areas.<\/li>\n<\/ol>\n
The development of water demand scenarios is described in [1], while the impacts of climate change on hydrological characteristics are presented in [2]. This article focuses on the final stage of the assessment: evaluating the security\u00a0of\u00a0water abstraction requirements and identifying locations that may be at risk of\u00a0water scarcity in\u00a0the\u00a0future. A\u00a0detailed description of\u00a0this stage of\u00a0the\u00a0assessment is provided in\u00a0the\u00a0corresponding research report\u00a0[3]. A\u00a0number of\u00a0organisations collaborated on WP1, particularly in\u00a0the\u00a0area of\u00a0forecasting water demand: the\u00a0TGM WRI (public water supply and energy sector abstractions; impacts of\u00a0climate change on hydrological characteristics and identification of\u00a0water-deficit areas; assessment of\u00a0water resource security; and identification of\u00a0potentially vulnerable locations); the\u00a0University of\u00a0Chemistry and Technology, Prague (industrial water demand); the\u00a0Institute of\u00a0Geology of\u00a0the\u00a0Czech Academy of\u00a0Sciences (water demand for irrigation under climate change impact scenarios); the\u00a0Czech Technical University in\u00a0Prague (irrigation); the\u00a0Czech University of\u00a0Life Sciences Prague (irrigation and livestock production); and the\u00a0Czech Hydrometeorological Institute (CHMI, the\u00a0effects of\u00a0abstractions and discharges on streamflow). The\u00a0WP1 activities within\u00a0the\u00a0Water Centre project build to some extent on Security Research Project No. VI20192022159, Water Management and Water Supply Systems and Preventive Measures to Reduce Risks in\u00a0Drinking Water Supply, carried out by the\u00a0TGM WRI between 2019 and 2022. Unlike WP1 of\u00a0the\u00a0Water Centre project, this project was limited to issues related to public water supply systems\u00a0[4, 5]. Owing to the\u00a0similarity of\u00a0the\u00a0methodologies applied, selected outputs from this project have also been incorporated into the\u00a0risk assessment results presented in\u00a0this paper. Detailed descriptions and the\u00a0results of\u00a0both projects are available on their respective websites\u00a0[6] and\u00a0[7].<\/p>\n
METHODOLOGY AND DATA<\/h2>\n
The\u00a0forecasting of\u00a0water resource security focused on assessing the\u00a0risk of\u00a0future failure to meet water abstraction requirements and, to a\u00a0certain\u00a0extent, minimum flow requirements. The\u00a0smallest spatial unit adopted for the\u00a0assessment was the\u00a0water body, or part thereof, as defined for the\u00a0purposes of\u00a0water management planning (a\u00a0total of\u00a01,118 surface water bodies and 1,220 groundwater body assessment units are defined in\u00a0the\u00a0Czech Republic). The\u00a0methodology and level of\u00a0detail of\u00a0the\u00a0assessment were largely determined by the\u00a0availability of\u00a0data. The\u00a0principal inputs to the\u00a0water resources\u2013water demands balance assessment were projected water abstraction requirements and projected values of\u00a0hydrological characteristics affected by climate change. These input data were developed directly within\u00a0WP1 of\u00a0the\u00a0Water Centre project\u00a0[1, 2] and the\u00a0Security Research Project\u00a0[4, 5].<\/p>\n
Input data<\/h3>\n
The\u00a0following datasets were used in\u00a0the\u00a0assessment:<\/p>\n
- \n
- Projected water abstractions for 2050, disaggregated by calendar month. Source: TGM WRI, University of\u00a0Chemistry and Technology, Prague; Czech Technical University in\u00a0Prague; and Czech University of\u00a0Life Sciences Prague\u00a0[1].<\/li>\n
- Time series of\u00a0modelled irrigation water demand projected for 2050. Source: Institute of\u00a0Geology of\u00a0the\u00a0Czech Academy of\u00a0Sciences\u00a0[1].<\/li>\n
- Data on water abstractions, discharges, water storage, and reservoir parameters (active storage volume and minimum outflow) recorded in\u00a0accordance with Decree No. 431\/2001 Coll. Source: River Basin\u00a0Authorities and TGM WRI\u00a0[8].<\/li>\n
- Data on the\u00a0proportion of\u00a0stormwater in\u00a0discharges to surface waters from\u00a0the\u00a0Water Supply and Sewerage Assets and Operations Register (sewer\u00a0network and wastewater treatment plant sections), maintained in\u00a0accordance with Decree No. 428\/2001 Coll. Source: Ministry of\u00a0Agriculture\u00a0[9].<\/li>\n
- Time series of\u00a0modelled monthly streamflow, evaporation, and baseflow from the\u00a0catchments of\u00a0gauging stations and the\u00a0inter-catchment areas of\u00a0surface water bodies. Source: TGM WRI\u00a0[2, 4].<\/li>\n
- Long-term and annual baseflow values for the\u00a0hydrogeological zones of\u00a0the\u00a0Czech Republic. Source: CHMI.<\/li>\n
- Reassessment of\u00a0groundwater resources. Source: Czech Geological Survey\u00a0[10].<\/li>\n
- Hydrogeological zoning. Project of\u00a0the\u00a0Government Council of\u00a0the\u00a0Czech Republic for Research and Development No. VaV\/650\/4\/02, Final Summary Report for the\u00a02002\u20132005 project period. Source: TGM WRI\u00a0[11].<\/li>\n<\/ul>\n
Hydrological conditions<\/h3>\n
Given the\u00a0uncertainties associated with predicting the\u00a0impacts of\u00a0climate change on hydrological characteristics, the\u00a0assessment of\u00a0water resource availability for 2050 was carried out using multiple scenarios. The\u00a0hydrological scenarios were defined by combinations of\u00a0climate models and emission scenarios\u00a0[2, 4]. An\u00a0overview of\u00a0the\u00a0climate models and emission scenarios considered is provided in\u00a0Tab.\u00a01<\/em>. The\u00a0HADGEM2-ES climate model and the\u00a0hydrological conditions corresponding to a\u00a02 \u00b0C increase in\u00a0temperature were assessed within\u00a0the\u00a0Security Research Project, and their impacts were evaluated only for public water supply abstractions\u00a0[4]. The\u00a0remaining climate models and emission scenarios were evaluated as part of\u00a0WP1 of\u00a0the\u00a0Water Centre project\u00a0[2]. Each combination of\u00a0a\u00a0climate model and an\u00a0emission scenario represents an\u00a0alternative projection of\u00a0future climatic conditions. This approach makes it possible to better capture the\u00a0uncertainties associated with future climate development and to assess the\u00a0robustness of\u00a0the\u00a0results under different climate scenarios.<\/p>\n
Tab. 1. Evaluated climate models and emission scenarios<\/h5>\n
![\"\"](\"data:image\/svg+xml;base64,PHN2ZyB3aWR0aD0iMSIgaGVpZ2h0PSIxIiB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciPjwvc3ZnPg==\")
<\/a>\nThe\u00a0SSP585 emission scenario is widely interpreted in\u00a0the\u00a0current scientific literature as a\u00a0high-emissions scenario representing the\u00a0upper bound of\u00a0potential future climate change. Although some experts no longer regard it as the\u00a0most likely trajectory of\u00a0future socioeconomic development, it remains an\u00a0appropriate scenario for risk assessment and for evaluating the\u00a0sensitivity of\u00a0water resources to potentially adverse climate change. Accordingly, in\u00a0the\u00a0present study, the\u00a0SSP585 scenario was not interpreted as the\u00a0most likely future scenario, but rather as one of\u00a0several scenarios used to assess the\u00a0range of\u00a0potential impacts of\u00a0climate change on water resource availability.<\/p>\n
Water abstraction requirements and minimum flows<\/h3>\n
In\u00a02021, a\u00a0total of\u00a05,602 water abstraction points were registered in\u00a0accordance with\u00a0[8], with a\u00a0total annual abstraction of\u00a0approximately 1,400\u00a0million m3<\/sup>\u00a0\u2219\u00a0year-1 <\/sup>(excluding abstractions for water transfers). These comprised 883 surface water abstraction points, with a\u00a0total annual abstraction of\u00a0approximately
\n1,030\u00a0million m3<\/sup>\u00a0\u2219\u00a0year-1<\/sup> (about 74\u00a0% of\u00a0the\u00a0total volume abstracted), and 4,719\u00a0groundwater abstraction points, with a\u00a0total annual abstraction of\u00a0approximately 370\u00a0million\u00a0m3<\/sup>\u00a0\u2219\u00a0year-1<\/sup> (about 26\u00a0% of\u00a0the\u00a0total volume abstracted). Whereas surface water abstractions are used extensively for public water supply, industry, energy production, and agriculture, groundwater abstractions are used primarily for public water supply.<\/p>\nWater abstraction requirements were considered under two scenarios: current water demand and projected water demand for 2050\u00a0[1].<\/p>\n
Current water demand was determined as follows:<\/p>\n
- \n
- Public water supply, energy production, and industrial abstractions were based on recorded monthly water abstraction data for the\u00a0period 2015\u20132021. Monthly water demand was calculated as the\u00a0arithmetic mean\u00a0of\u00a0the\u00a0recorded abstractions for all economic sectors except agriculture.<\/li>\n
- Agricultural abstractions were determined as the\u00a0maximum monthly values recorded during the\u00a0same period (abstractions for irrigation increase substantially during dry periods).
\nProjected water demand (the\u00a0high scenario) was determined as follows:<\/li>\n - Public water supply abstractions were based on the\u00a0average monthly abstractions for the\u00a0period 2016\u20132021, adjusted according to the\u00a0high demographic development scenario.<\/li>\n
- Energy sector abstractions were projected for 2050 based on the\u00a0supporting documents for the\u00a0national energy strategy.<\/li>\n
- Industrial abstractions were determined as the\u00a0maximum recorded annual abstraction during the\u00a0period 2009\u20132021, distributed evenly throughout the\u00a0year.<\/li>\n
- Agricultural abstractions were determined as the\u00a0maximum abstractions recorded for each calendar month during the\u00a0period 2015\u20132021.<\/li>\n
- Irrigation demand was represented by time series of\u00a0monthly irrigation water demand for the\u00a0inter-catchment areas of\u00a0surface water bodies for\u00a0the\u00a0individual climate models and emission scenarios, using the\u00a0following variants:\n
- \n
- \n
prevention of drought stress,<\/p>\n<\/li>\n
- \n
optimisation of\u00a0crop production.<\/p>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n
The\u00a0security of\u00a0minimum flows was assessed on the\u00a0basis of\u00a0the\u00a0current minimum reservoir outflow requirements and the\u00a0active augmentation of\u00a0minimum flows at downstream control points.<\/p>\n
Methodology for assessing surface water resources<\/h3>\n
The\u00a0security of\u00a0surface water abstractions and minimum flows in\u00a0watercourses was assessed using water balance methods and simulation modelling of\u00a0the\u00a0storage function of\u00a0water management systems. The\u00a0modelling approach is described in\u00a0detail in\u00a0[12]. The\u00a0model simulates the\u00a0behaviour of\u00a0the\u00a0water management system as a\u00a0chronological sequence of\u00a0discrete time steps (a\u00a0monthly time step was adopted in\u00a0this study). The\u00a0simulation is based on time series of\u00a0natural streamflow (i.e. unaffected by regulation or water abstractions\/discharges), water use requirements (water abstractions in\u00a0this study), minimum flow requirements, the\u00a0technical parameters of\u00a0the\u00a0system components (here, the\u00a0active storage volumes of\u00a0reservoirs and the\u00a0capacities of\u00a0water transfers), and the\u00a0operating rules incorporated into the\u00a0model for regulating outflows (i.e. reservoir operating rules governing releases from active storage). The\u00a0model outputs time series of\u00a0simulated variables, including streamflow, reservoir surface evaporation, water abstractions, reservoir outflows, and water volumes and water levels within\u00a0the\u00a0active storage zone of\u00a0reservoirs. These time series are subsequently subjected to statistical analysis. The\u00a0primary indicator used to express the\u00a0security of\u00a0water abstractions is the\u00a0duration-based security index (Pt), defined in\u00a0[13] (in\u00a0simplified terms, it expresses the\u00a0percentage of\u00a0the\u00a0total assessment period during which water abstraction requirements or minimum flow requirements are fully met). Water management simulations were carried out using the\u00a0\u201cSimulation Model of\u00a0the\u00a0Storage Function of\u00a0a\u00a0Water Management System\u201d\u00a0[14], developed by TGM WRI.<\/p>\n
In\u00a0the\u00a0reference year 2021, the\u00a0water abstraction register maintained in\u00a0accordance with\u00a0[8] included 82 reservoirs and 14 water transfers relevant to the\u00a0provision of\u00a0storage capacity, as well as 883 surface water abstraction points. For the\u00a0assessment, abstraction points with an\u00a0annual abstraction exceeding 500 thousand m3<\/sup>\u00a0\u2219\u00a0year-1<\/sup> were selected. A\u00a0total of\u00a0132 abstraction points met this criterion. These abstraction points accounted for approximately 90\u00a0% of\u00a0the\u00a0total volume of\u00a0surface water abstracted. The\u00a0selected abstraction points are shown in\u00a0Fig.\u00a02<\/em>. The\u00a0effects of\u00a0the\u00a0remaining (smaller) water abstractions were incorporated into the\u00a0assessment in\u00a0aggregated form at the\u00a0nearest water management system point. Similarly, the\u00a0effects of\u00a0all groundwater abstractions (by projecting the\u00a0abstraction points onto the\u00a0river network) and water discharges were also incorporated in\u00a0aggregated form. The\u00a0water management system also included 16 control points at which the\u00a0active augmentation of\u00a0minimum flows by reservoirs was assessed, together with 222 outlet points of\u00a0surface water bodies, where the\u00a0potential to meet irrigation demand within\u00a0the\u00a0corresponding inter-catchment areas was evaluated.<\/p>\n
<\/a>\nFig.\u00a02. Locations of\u00a0significant surface water abstraction<\/h6>\n
The\u00a0storage function was simulated for each assessment scenario using a\u00a0monthly time step and a\u00a0chronological hydrological dataset comprising time series of\u00a0modelled natural mean\u00a0monthly streamflow and evaporation over a\u00a0period of\u00a030 years (or 60 years in\u00a0the\u00a0Security Research Project). For each water abstraction and minimum flow requirement considered, the\u00a0simulation model then calculated the\u00a0corresponding security level and compared it with the\u00a0security level recommended by Czech Standard \u010cSN 75 2405\u00a0[13].<\/p>\n
Methodology for assessing groundwater resources<\/h3>\n
The\u00a0adequacy of\u00a0groundwater resources was assessed using water balance methods for evaluating the\u00a0current and projected status of\u00a0groundwater quantity\u00a0[15], together with procedures for assessing the\u00a0quantitative status of\u00a0groundwater bodies\u00a0[16]. A\u00a0limitation of\u00a0applying these established nationwide methods was the\u00a0availability of\u00a0input data on natural groundwater resources, which were compiled only at the\u00a0scale of\u00a0hydrogeological zones (152 in\u00a0total), with areas of\u00a0up to 5,800 km\u00b2. Consequently, the\u00a0final results could, in\u00a0practice, represent only part of\u00a0the\u00a0assessed area. A\u00a0new stage of\u00a0quantitative groundwater status assessment is currently being completed, in\u00a0which the\u00a0water balance is calculated directly at the\u00a0scale of\u00a0groundwater bodies (174\u00a0in\u00a0total). However, this is based only on the\u00a0redistribution of\u00a0natural groundwater resources according to the\u00a0proportion of\u00a0each groundwater body\u2019s\u00a0area relative to that of\u00a0the\u00a0corresponding hydrogeological zone. The\u00a0only exception is the\u00a0quaternary upper-layer groundwater bodies, for which the\u00a0methodology for assessing quantitative status has been completely revised. The\u00a0first project to apply a\u00a0more sophisticated approach to assessing natural groundwater resources at a\u00a0finer spatial resolution over a\u00a0large part of\u00a0the\u00a0Czech Republic was the\u00a0Security Research Project\u00a0[5], carried out between 2019 and 2022. In\u00a0this project, the\u00a0current status and projected changes in\u00a0baseflow were calculated at the\u00a0scale of\u00a0the\u00a0inter-catchment areas of\u00a0surface water bodies (1,118 in\u00a0total), providing data for 825 groundwater body assessment units (out of\u00a01,220) under Variant II. In\u00a0the\u00a0Water Centre project, the\u00a0risk of\u00a0future inadequacy of\u00a0groundwater resources for groundwater abstractions was likewise assessed at the\u00a0level of\u00a0groundwater working units.<\/p>\n
On the\u00a0groundwater resource side, long-term estimates of\u00a0natural groundwater resources were taken from the\u00a0Groundwater Resource Reassessment\u00a0[10] (covering natural resources with 50\u00a0% and 80\u00a0% security, as well as exploitable groundwater resources), from data provided by the\u00a0CHMI (natural resources with 50\u00a0% and 80\u00a0% security), and, as supplementary information, from the\u00a0Hydrogeological Zoning 2005 project\u00a0[11] (equivalent to natural resources with 50\u00a0% security). All these values were subsequently downscaled to the\u00a0smaller groundwater body assessment units using the\u00a0outputs of\u00a0the\u00a0current-state hydrological balance model.<\/p>\n
In assessing the risk of insufficient groundwater resources for groundwater abstractions, the impacts of all climate models and emission scenarios on changes in baseflow were first evaluated using spatial analysis. Subsequently, the combination of the ALADIN-CLIMATE\/CZ climate model and the SSP585 emission scenario for 2050 (within the Water Centre project), and the HADGEM2-ES climate model and the RCP4.5 emission scenario for the 2041\u20132060 period (within\u00a0the\u00a0Security Research Project), were selected as the\u00a0representative scenarios.<\/p>\n
On the\u00a0demand side, the\u00a0groundwater resource balance is based on groundwater abstraction data converted to L\u00a0\u2219\u00a0s-1<\/sup>. For the\u00a0Water Centre project, the\u00a0following values were determined:<\/p>\n
- \n
- total annual abstractions for the\u00a0period 2016\u20132021 for hydrogeological zones and groundwater body assessment units,<\/li>\n
- average annual abstractions for the\u00a0period 2016\u20132021 for hydrogeological zones and groundwater body assessment units,<\/li>\n
- projected abstractions for 2050, calculated using the\u00a0methodology developed for the\u00a0Water Centre<\/em> project (high scenario).<\/li>\n<\/ul>\n
The\u00a0Water Centre<\/em> project included only groundwater abstractions recorded in\u00a02021, expressed as average annual values for the\u00a0period 2016\u20132021, whereas the\u00a0Security Research Project used data for the\u00a0period 2013\u20132018. Abstractions for drinking water supply amounted to approximately 308\u00a0million m3<\/sup>\u00a0\u2219\u00a0year-1<\/sup>, representing about 82\u00a0% of\u00a0the\u00a0total volume of\u00a0groundwater abstracted (from 64\u00a0% of\u00a0the\u00a0registered abstraction points), while other abstractions totalled approximately 65\u00a0million m3<\/sup>\u00a0\u2219\u00a0year-1<\/sup>, accounting for about 18\u00a0% of\u00a0the\u00a0abstracted volume (from the\u00a0remaining 36\u00a0% of\u00a0registered groundwater abstraction points). Projected abstractions comprised unchanged non-potable water abstractions together with drinking water abstractions for each water balance unit, adjusted according to the\u00a0projected demographic development up to 2050. The\u00a0projected groundwater abstraction requirements based on the\u00a0expected demographic development to 2050 are shown in\u00a0Fig.\u00a03<\/em>.<\/p>\n
<\/a>\nFig.\u00a03. Projected groundwater abstraction requirements by 2050<\/h6>\n
Only 271 of\u00a0the\u00a01,220 groundwater body assessment units, namely those with annual groundwater abstractions of\u00a0at least 5\u00a0L\u00a0\u2219\u00a0s-1<\/sup>\u00a0in\u00a02021, were included in\u00a0the\u00a0water balance comparison of\u00a0groundwater abstractions and natural groundwater resources. The\u00a0remaining 949 assessment units were not evaluated in\u00a0the\u00a0Water Centre project, just as 395 assessment units had been excluded from the\u00a0future projections in\u00a0the\u00a0Security Research Project. This is because water balance assessments involving very small abstraction volumes are subject to considerable uncertainty.<\/p>\n
RESULTS<\/h2>\n
The\u00a0procedures described above resulted in\u00a0an\u00a0assessment of\u00a0the\u00a0adequacy of\u00a0water resources in\u00a0relation to water abstraction and minimum flow requirements. Because of\u00a0the\u00a0large number of\u00a0scenarios assessed and the\u00a0corresponding volume of\u00a0data, the\u00a0detailed results are presented in\u00a0the\u00a0relevant specialised public database (see below). The\u00a0results presented here are therefore provided in\u00a0summary form.<\/p>\n
Surface water resources<\/h3>\n
The\u00a0assessment of\u00a0the\u00a0security of\u00a0surface water abstractions and minimum flows downstream of\u00a0reservoirs was carried out for more than\u00a050 scenarios combining the\u00a0hydrological conditions considered (climate models and emission scenarios) with the\u00a0required water abstraction volumes.<\/p>\n
The\u00a0risk of\u00a0failing to meet surface water abstraction or minimum flow requirements by 2050 is expressed for each assessment point, across all scenarios considered, using the\u00a0following classification:<\/p>\n
- \n
- High risk: The\u00a0requirement is not fully met under any scenario, and in\u00a0at least one scenario fails to achieve the\u00a0level of\u00a0security recommended by the\u00a0standard\u00a0[13].<\/li>\n
- Low risk: The\u00a0requirement is fully met under all scenarios.<\/li>\n
- Medium risk: All other cases.<\/li>\n<\/ul>\n
The\u00a0results are illustrated in\u00a0Fig.\u00a04<\/em>. The\u00a0reservoirs identified as being at\u00a0risk, together with the\u00a0minimum and maximum duration-based security (Pt<\/sub>) achieved for the\u00a0water abstractions and\/or minimum flows they support under the\u00a02050 scenarios, are presented in\u00a0Tab.\u00a02<\/em>.<\/p>\n
<\/a>\nFig.\u00a04. Risk of\u00a0failing to meet surface water abstraction requirements and minimum flow rates by 2050<\/h6>\n
Tab. 2. Water reservoirs at risk of failing to meet surface water abstraction requirements and\/or minimum flow rates by 2050<\/h5>\n
<\/a>\nThe\u00a0Obecnice public water supply reservoir, together with the\u00a0B\u0159ezov\u00e1, \u010cesk\u00e9 \u00dadol\u00ed, and Klabava reservoirs, was identified as being at high risk. A\u00a0further 29 reservoirs, including 19 public water supply reservoirs, were classified as\u00a0presenting a\u00a0medium risk.<\/p>\n
Groundwater resources<\/h3>\n
For the\u00a0assessment, the\u00a0critical threshold values for the\u00a0ratio of\u00a0groundwater abstractions to natural groundwater resources were adopted from the\u00a0procedures used to assess quantitative groundwater status, namely 0.4 for natural groundwater resources with 50\u00a0% security and 0.5 for natural groundwater resources with 80\u00a0% security. For the\u00a0comparison of\u00a0groundwater abstractions with exploitable groundwater resources, water balance ratios were not calculated. Instead, the\u00a0average annual abstractions for the\u00a0period 2016\u20132021 were subtracted from the\u00a0exploitable groundwater resources, and the\u00a0proportion of\u00a0the\u00a0remaining (unutilised) resources relative to the\u00a0total exploitable groundwater resources was compared with the\u00a0critical threshold of\u00a020\u00a0% (i.e. the\u00a0result was considered unsatisfactory if the\u00a0proportion of\u00a0unutilised resources was less than\u00a00.2).<\/p>\n
In\u00a0addition to assessment units with very small groundwater abstractions, hydrogeological zone 3110 Pavlovsk\u00e9 vrchy was also excluded from the\u00a0water balance assessment because natural groundwater resources have not been quantified for this region by any method, and it does not contain\u00a0any significant groundwater abstractions.<\/p>\n
The\u00a0synthesis of\u00a0the\u00a0individual water balance comparisons between groundwater abstractions and natural groundwater resources (six comparisons for the\u00a0current state and six for the\u00a0projected state) gave slightly greater weight, as a\u00a0precautionary measure, to unfavourable results based on the\u00a0ratio to natural groundwater resources with 50\u00a0% security. The\u00a0results of\u00a0the\u00a0comparisons with natural groundwater resources having 80\u00a0% security, and of\u00a0the\u00a0comparisons with exploitable groundwater resources, were considered less reliable. Zero abstractions did not, logically, worsen the\u00a0final status classification, whereas zero natural groundwater resources did. The\u00a0final synthesis was also adversely affected by the\u00a0number of\u00a0water balance comparisons that could not be performed because of\u00a0the\u00a0absence of\u00a0data on natural groundwater resources in\u00a0assessment units where at least one comparison had produced an\u00a0unfavourable result.<\/p>\n
The\u00a0water balance assessment resulted in\u00a0an\u00a0evaluation of\u00a0both the\u00a0current and the\u00a0projected status (the\u00a0results for 2050 are shown in\u00a0Fig.\u00a05<\/em>). Using the\u00a0ALADIN-CLIMATE\/CZ climate model, the\u00a0SSP585 emission scenario for natural groundwater resources, and the\u00a0projected demographic development, relatively few groundwater body assessment units were identified as being at risk. Of\u00a0the\u00a0assessment units evaluated, 47 were classified as high risk (covering 6.6\u00a0% of\u00a0the\u00a0area), 16 as medium risk (1.5\u00a0% of\u00a0the\u00a0area), and 208 as low risk (39.7\u00a0% of\u00a0the\u00a0area). The\u00a0remaining 949 assessment units (52.2\u00a0% of\u00a0the\u00a0area) were not evaluated because groundwater abstractions were very small (less than\u00a05\u00a0L\u00a0\u2219\u00a0s-1<\/sup>), resulting in\u00a0an\u00a0unacceptably high level of\u00a0uncertainty.<\/p>\n
<\/a>\nFig.\u00a05. Proportion of\u00a0work units (PRJ) at risk of\u00a0groundwater abstraction shortages by 2050 in\u00a0hydrogeological zones<\/h6>\n
For hydrogeological zones in\u00a0which at least one groundwater body assessment unit was identified as being at risk under the\u00a0projected conditions, summary statistics were compiled based on the\u00a0percentage of\u00a0the\u00a0region\u2019s\u00a0area represented by the\u00a0individual assessment units (see Fig.\u00a06<\/em>). The\u00a0proportion of\u00a0the\u00a0area that could not be evaluated reached as much as 84.4\u00a0% in\u00a0some hydrogeological zones. Nevertheless, the\u00a0results clearly showed that the\u00a0risk assessment can\u00a0vary considerably within\u00a0individual hydrogeological zones, demonstrating that assessing future conditions at a\u00a0finer spatial resolution is worthwhile despite the\u00a0inherent uncertainties of\u00a0future projections.<\/p>\n
For the\u00a0ALADIN-CLIMATE\/CZ climate model and the\u00a0SSP585 emission scenario, the\u00a0total average annual groundwater abstraction during the\u00a0assessment period 2016\u20132021 was 11,627\u00a0L\u00a0\u2219\u00a0s-1<\/sup>, while the\u00a0total projected abstraction for 2050 was 11,665\u00a0L\u00a0\u2219\u00a0s-1<\/sup>. Of\u00a0the\u00a0total projected groundwater abstraction for 2050, 29.2\u00a0% (3,410\u00a0L\u00a0\u2219\u00a0s-1<\/sup>) was associated with groundwater body assessment units classified as high risk, 5.8\u00a0% (681\u00a0L\u00a0\u2219\u00a0s-1<\/sup>) with medium-risk units, 56.3\u00a0% (6,567\u00a0L\u00a0\u2219\u00a0s-1<\/sup>) with low-risk units, and 8.6\u00a0% (1,007\u00a0L\u00a0\u2219\u00a0s-1<\/sup>) with assessment units that were not evaluated.<\/p>\n
Within\u00a0the\u00a0Security Research Project, 825 of\u00a0the\u00a01,220 groundwater body assessment units were evaluated using the\u00a0HADGEM2-ES climate model and the\u00a0RCP4.5 emission scenario for the\u00a02050 projection. Of\u00a0these, 91 assessment units, covering 11.1\u00a0% of\u00a0the\u00a0Czech Republic, were classified as high risk, 37 units (6.1\u00a0% of\u00a0the\u00a0country\u2019s\u00a0area) as medium risk, and 697 units (67.1\u00a0% of\u00a0the\u00a0country\u2019s\u00a0area) as low risk (Fig.\u00a06<\/em>). The\u00a0remaining assessment units were not evaluated because groundwater abstractions were too small.<\/p>\n
<\/a>\nFig.\u00a06. Comparison of\u00a0risk assessment results for the\u00a0ALADIN-CLIMATE\/CZ climate model under the\u00a0SSP585 scenario (Water Centre \u2013 CEVO) and the\u00a0HADGEM2-ES climate model under the\u00a0RCP4.5 emissions scenario (Security research)<\/h6>\n
Finally, the\u00a0results from the\u00a0Water Centre project and the\u00a0Security Research Project were synthesised by adopting the\u00a0more adverse classification from the\u00a0two assessments for each groundwater body assessment unit. In\u00a0total, 838\u00a0of\u00a0the\u00a01,220 groundwater body assessment units were evaluated, of\u00a0which 106 units, covering 12.7\u00a0% of\u00a0the\u00a0Czech Republic, were classified as high risk, 43 units (6.1\u00a0% of\u00a0the\u00a0country\u2019s\u00a0area) as medium risk, and 689 units (66.3\u00a0% of\u00a0the\u00a0country\u2019s\u00a0area) as low risk (Figs. 6<\/em> and 7<\/em>). The\u00a0remaining 382 assessment units (14.9\u00a0% of\u00a0the\u00a0country\u2019s\u00a0area) were not evaluated.<\/p>\n
Groundwater body assessment units identified as being at risk are shown in\u00a0the\u00a0overview map in\u00a0Fig.\u00a0<\/em>7.<\/p>\n
<\/a>\nFig.\u00a07. The\u00a0risk of\u00a0insufficient groundwater resources for abstraction by 2050<\/h6>\n
Public specialised database<\/h3>\n
The\u00a0detailed results of\u00a0the\u00a0water resource security assessment have been incorporated into the\u00a0specialised public databases developed within\u00a0the\u00a0two projects\u00a0[17, 7]. The\u00a0data are available through web-based map services in\u00a0the\u00a0form of\u00a0interactive maps and linked tables. The\u00a0user interface is shown in\u00a0Figs.\u00a08<\/em> and 9<\/p>\n
<\/a>\nFig.\u00a08. Browser Service User Interface: Map section<\/h6>\n
<\/a>\nFig.\u00a09. Browser Service User Interface: Table view<\/h6>\n
DISCUSSION<\/h2>\n
Assessing future water resource security is a\u00a0complex undertaking. Its modelling at the\u00a0scale of\u00a0the\u00a0entire Czech Republic requires a\u00a0number of\u00a0necessary simplifications and is subject to considerable uncertainty. The\u00a0principal sources of\u00a0uncertainty include the\u00a0following. The\u00a0time horizon of\u00a02050 was selected in\u00a0accordance with the\u00a0objectives of\u00a0the\u00a0Water Centre project and, at the\u00a0same time, represents a\u00a0period for which not only the\u00a0evolution of\u00a0climatic conditions, but also future water abstraction requirements and the\u00a0state of\u00a0water management infrastructure, can\u00a0still be projected with a\u00a0reasonable degree of\u00a0confidence. Extending the\u00a0projection to 2100 would substantially increase the\u00a0uncertainties associated not only with climate models, but also with demographic, economic, and technological developments. For this reason, the\u00a0results should primarily be regarded as a\u00a0basis for the\u00a0medium-term planning of\u00a0climate adaptation measures over the\u00a0coming decades. They should not be interpreted as a\u00a0definitive prediction of\u00a0future conditions, but rather as an\u00a0assessment of\u00a0the\u00a0range of\u00a0possible future developments under different combinations of\u00a0climatic and socioeconomic assumptions.<\/p>\n
A major source of uncertainty in the assessment results is the prediction of the impacts of climate change on hydrological characteristics and, to a lesser extent, the projection of future water abstraction requirements. This uncertainty is reflected in the use of multiple assessment scenarios. Consequently, the assessed level of water resource security also exhibited a degree of variability (e.g. for the Kl\u00ed\u010dava, Obecnice, Stanovice, and Hamry reservoirs), with many locations being identified as at risk only under some of the less favourable scenarios. The highest levels of identified risk generally occurred for combinations of climate models with the SSP585 emission scenario, which should be regarded primarily as representing the upper bound of the potential impacts of climate change. This scenario was not interpreted in the present study as the most likely future development, but rather as one of the scenarios used to\u00a0assess the\u00a0range of\u00a0potential future risks to water resources. The\u00a0assessment of\u00a0groundwater resources is subject to uncertainties arising from the\u00a0current estimates of\u00a0groundwater resources, the\u00a0heterogeneity of\u00a0natural groundwater resources within\u00a0hydrogeological zones, and the\u00a0approximation of\u00a0natural groundwater resources under future conditions.<\/p>\n
Water abstractions are constrained by the\u00a0need to preserve the\u00a0ecological functioning of\u00a0watercourses. At present, this requirement is addressed by maintaining so-called minimum residual flows. A\u00a0Government Regulation is currently being prepared that is intended to bring the\u00a0method for determining minimum residual flows more closely into line with the\u00a0requirements of\u00a0the\u00a0EU Water Framework Directive. In\u00a0this study, the\u00a0assessment of\u00a0minimum flow security was limited to flows actively maintained by reservoirs (i.e. the\u00a0minimum reservoir outflow and, where applicable, the\u00a0active augmentation of\u00a0minimum flows at downstream control points). For the\u00a0remaining assessment points, no projected minimum flow was determined and, consequently, its level of\u00a0security was not classified.<\/p>\n
Water abstraction requirements are based primarily on an\u00a0analysis of\u00a0recorded water abstractions. However, actual water abstractions may not accurately represent current water abstraction requirements, as the\u00a0volume abstracted can\u00a0vary in\u00a0response to a\u00a0range of\u00a0factors, such as industrial operating conditions (e.g. plant shutdowns) or drought (e.g. abstraction restrictions resulting from insufficient water resources or increased irrigation demand due to soil moisture deficits). Difficulties in\u00a0determining water abstraction requirements and the\u00a0corresponding water sources may also arise in\u00a0public water supply systems, where water may be abstracted from multiple sources (watercourses or reservoirs), and the\u00a0volume abstracted from a\u00a0particular source may vary depending on other operational factors. In\u00a0addition, the\u00a0permitted abstraction volume often differs substantially from the\u00a0volume actually abstracted and, in\u00a0many cases, is considerably higher.<\/p>\n
CONCLUSION<\/h2>\n
The\u00a0aim of\u00a0the\u00a0assessment described above was to evaluate the\u00a0security of\u00a0water abstractions and minimum flows supplied by surface water and groundwater resources under projected conditions for 2050, and to identify potentially vulnerable locations. Water abstraction security was assessed using simulation modelling (for surface water resources), water balance methods, and procedures for assessing the\u00a0quantitative status of\u00a0groundwater bodies. The\u00a0assessment was carried out at the\u00a0national scale. The\u00a0principal input data comprised time series of\u00a0modelled streamflow, evaporation, and baseflow from the\u00a0catchments of\u00a0gauging stations and the\u00a0inter-catchment areas of\u00a0surface water bodies under projected climate change conditions, together with projected water abstraction requirements. Existing reservoir and water transfer infrastructure, including their capacities, was taken into account. The\u00a0uncertainties associated with projecting future developments were addressed by considering multiple assessment scenarios. Water abstraction requirements were evaluated for both current recorded abstractions and projected future abstractions. The\u00a0potential impacts of\u00a0climate change on water resources were considered using combinations of\u00a0climate models and emission scenarios. Sources of\u00a0uncertainty in\u00a0the\u00a0assessment include the\u00a0determination of\u00a0water abstraction requirements (e.g. the\u00a0long-term discrepancies between permitted and actual abstraction volumes), the\u00a0treatment of\u00a0minimum residual flows, and the\u00a0interaction between surface water and groundwater. The\u00a0assessment of\u00a0surface water resources identified 33 reservoirs (out of\u00a0the\u00a082 assessed) as potentially being at\u00a0risk. Groundwater resources were evaluated for 838 groundwater body assessment units (out of\u00a0the\u00a01,220 in\u00a0the\u00a0Czech Republic), of\u00a0which 106 units, covering 12.7\u00a0% of\u00a0the\u00a0country\u2019s\u00a0area, were classified as high risk, 43 units (6.1\u00a0% of\u00a0the\u00a0area) as medium risk, and 689 units (66.3\u00a0% of\u00a0the\u00a0area) as low risk. The\u00a0remaining 382\u00a0assessment units (14.9\u00a0% of\u00a0the\u00a0country\u2019s\u00a0area) were excluded from the\u00a0projected assessment because groundwater abstractions were too small (less than\u00a05\u00a0L\u00a0\u2219\u00a0s-1<\/sup>), resulting in\u00a0an\u00a0unacceptable level of\u00a0uncertainty. For the\u00a0ALADIN-CLIMATE\/CZ climate model and the\u00a0SSP585 emission scenario, groundwater body assessment units classified as\u00a0high risk accounted for 29.2\u00a0% of\u00a0the\u00a0total projected groundwater abstraction for 2050 (3,410\u00a0L\u00a0\u2219\u00a0s-1<\/sup>\u00a0out of\u00a0a\u00a0national total of\u00a011,665\u00a0L\u00a0\u2219\u00a0s-1<\/sup>), while medium-risk units accounted for 5.8\u00a0% (681\u00a0L\u00a0\u2219\u00a0s-1<\/sup>), low-risk units for 56.3\u00a0% (6,567\u00a0L\u00a0\u2219\u00a0s-1<\/sup>), and assessment units not included in\u00a0the\u00a0evaluation for 8.6\u00a0% (1,007\u00a0L\u00a0\u2219\u00a0s-1<\/sup>).<\/p>\n
The\u00a0assessment results have been incorporated into the\u00a0relevant specialised public databases. Despite the\u00a0uncertainties and necessary simplifications associated with conducting the\u00a0assessment at the\u00a0national scale, the\u00a0identification of\u00a0surface water and groundwater resources that may be at risk in\u00a0the\u00a0future provides a\u00a0valuable basis for more detailed investigations and the\u00a0timely preparation of\u00a0measures to reduce these risks.<\/p>\n
Acknowledgements<\/h3>\n
This article is based on research carried out within\u00a0Project No. SS02030027, Water Systems and Water Management in\u00a0the\u00a0Czech Republic under Climate Change, funded by the\u00a0Technology Agency of\u00a0the\u00a0Czech Republic under Subprogramme\u00a03\u00a0\u2013 Long-term Environmental and Climate Perspectives of\u00a0the\u00a0SS Programme \u2013 Programme for Applied Research, Experimental Development and Innovation in\u00a0the\u00a0Environment \u2013 Environment for Life, and Project No. VI20192022159, Water Management and Water Supply Systems and Preventive Measures to Reduce Risks in\u00a0Drinking Water Supply, funded by the\u00a0Ministry of\u00a0the\u00a0Interior of\u00a0the\u00a0Czech Republic under Programme BV III\/1-VS.<\/em><\/p>\n
The Czech version of this article was peer-reviewed, the English version was translated from the Czech original by Environmental Translation Ltd.<\/p>\n","protected":false},"excerpt":{"rendered":"
This article presents the methods and results of an assessment of the security of water abstraction and minimum flow rates through 2050, taking into account the potential impacts of climate change on water resources and projected water demand based on socioeconomic development forecasts. The study was conducted on a national scale. Water bodies defined for water planning purposes were selected as the minimum spatial scale.<\/p>\n","protected":false},"author":8,"featured_media":39508,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":"","_members_access_role":[],"_members_access_error":""},"categories":[94,86,93],"tags":[96,870,873,649,484],"coauthors":[757,758,3158,2507,27],"class_list":["post-39303","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-current-issue","category-hydraulics-hydrology-and-hydrogeology","category-two-articles","tag-climate-change","tag-water-balance","tag-water-resources","tag-water-scarcity","tag-water-supply"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/39303","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/comments?post=39303"}],"version-history":[{"count":4,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/39303\/revisions"}],"predecessor-version":[{"id":39734,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/posts\/39303\/revisions\/39734"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media\/39508"}],"wp:attachment":[{"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/media?parent=39303"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/categories?post=39303"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/tags?post=39303"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/www.vtei.cz\/en\/wp-json\/wp\/v2\/coauthors?post=39303"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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