HS1.1.4

There has been increasing recognition that the global water crisis is due to lack of understanding of wider economic and socio-cultural perspectives, resulted from the intended and/or unintended consequences of co-evolution of coupled human-water systems. In light of such recognition, Panta Rhei Initiative (2013-2022) was proposed to focus on changes in both hydrology and society. Approaching end of this decade, this study present the synthesis of knowledge gained in our understanding of coevolution and prediction of coupled human-water systems. Content include five parts: (I) Motivation and Overview, (II) Theoretical Foundations and Methodological Approaches, (III) Synthesis of Work Done and Understanding Gained in Specific Application Areas, (IV) Panta Rhei Case Studies, (V) Grand Synthesis and Recommendations.

How to cite: Tian, F., Haeffner, M., Kreibich, H., Mukherji, A., Wei, J., Sivapalan, M., and Blöschl, G.: Coevolution and Prediction of Coupled Human-Water Systems: A Synthesis of Change in Hydrology and Society, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-36, https://doi.org/10.5194/egusphere-egu22-36, 2022.

Impacts and trade-offs between society and hydrological processes cover a wide range of issues, for which climate, geography, environment, cultural context, economy, and society altogether result in largely different coevolution schemes and current scenarios. This work presents a selection of case studies addressing the Panta Rhei Decade’s goals and discussions, that cover representative examples to assess future challenges of sociohydrology to be included in the Panta Rhei Book results. As a follow-up of the work progress presented in previous conferences, we focus now on each storyline to highlight their contribution to the Panta Rhei decade’s work and impact on future reflections, and pathways.

Specifically, some similarities and major divergences are assessed between local cases across geography and topics in a preliminary attempt to identify the key conclusions of this paradigm and the most relevant sectors dealing with socio-hydrological processes now, and in the future. These results pave the line towards the final lessons learnt from this process, to be presented in the XXIst Scientific Assembly of the IAHS.

How to cite: Polo, M. J., Vail, C., Penny, G., Gunda, T., and Montanari, A.: Contribution of local examples of co-evolution of society and hydrology to address current and future challenges of sustainability in the context of the Panta Rhei Book, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12216, https://doi.org/10.5194/egusphere-egu22-12216, 2022.

There is a reason why Iceland is frequently called the land of fire and ice. Located on the mid-Atlantic ridge in the North Atlantic Ocean, Iceland is frequently exposed to explosive volcanic eruptions. Furthermore, due to its geographic location cold Arctic winds from the North and the warm humid winds coming from the Gulf of Mexico collide. The particular geographic location is the reason why over 10% of the Island area is covered by glaciers, precipitation can exceed 10´000 mm a-1, and glacial flood can reach several 100’000 m3 s-1. Regardless of the arctic winds, the extreme precipitation, and the frequent eruption, the original Icelandic vegetation has developed a resilience to with sand almost any natural hazard. However, with the arrival of the first settler over a millennium ago Iceland has been subject to dramatic deforestation due to intense sheep and horse farming. These anthropogenic impacts have severely mitigated the resilience of the Icelandic vegetation, altering the erosion patterns and finally also impacting the natural water flow. The Rangárvellir area in southern Iceland is an ideal location to study the interaction of human impacts, natural hazards, and consequences for the natural water cycle. Deforestation and intensive farming have decreased the resilience of the local ecosystems, leading to severe land degradation and extensive soil erosion. Since the beginning of the 20th century, diverse restoration measures have been implemented across Rangárvellir. Long-term monitoring programs demonstrate how restoration can help mitigate hydrometeorological and volcanic risks, providing a representative example of nature-based solutions. For this purpose, we present a metadatabase (http://rangarvellir.ru.is/) providing an overview of previous and ongoing research on land restoration, land management, reforestation, hydro-meteorological monitoring, and vegetation mapping. All relevant past and ongoing research and restoration projects are described in order to demonstrate the importance of an all-inclusive landscape restoration approach. The study concludes by outlining the importance of nature-based solutions and highlights the interaction between research projects in the frame of restoration and land reclamation efforts.

How to cite: Finger, D. C.: Hydrology at its extreme: climate change, societal impacts and natural hazards in the land of fire and ice, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4543, https://doi.org/10.5194/egusphere-egu22-4543, 2022.

Human pressure on surface water is increasing globally, especially on river systems. Future scenarios of urban population growth anticipate an overexploitation of surface water resources in the proximity of cities, which in turn will produce environmental, social, and economic impacts whose effects are going to influence increasingly larger areas. Therefore, it is crucial to gain a better understanding of the dynamics of interaction between human settlements and surface water, to find a balance between urban planning and water management policies that ensure water conservation and ecosystem protection. In this study we assess the driving role of urban areas in the spatial distribution of surface water losses across the contiguous United States (CONUS). In particular, we analyze the frequency of occurrence of surface water loss as a function of distance from urban areas using remote sensing data and we define a distance decay model that reproduces the observed spatial behavior. We find that the frequency of surface water loss declines as the distance from urban areas increases and we successfully model this spatial trend with an exponential probability distribution function. Moreover, we observe distinct decay patterns of the frequency of occurrence of surface water loss associated to the main climatic conditions of the CONUS, as surface water losses are more concentrated around urban areas in regions with a temperate and continental climate, while they result to be more widespread over greater distances in regions with an arid climate.

How to cite: Palazzoli, I., Montanari, A., and Ceola, S.: Spatial distribution of surface water losses from urban areas across the contiguous United States, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8511, https://doi.org/10.5194/egusphere-egu22-8511, 2022.

Uncertainties and indeterminate scope, divergent social values and stakeholder interests, and changing hydroclimatology in transboundary river basins are all factors that may complicate sustainable water resource management. To address such complex socio hydrological issues, we present an example of an integrated approach to assessing future sustainability challenges in their social, hydrological, and ecological dimensions using a case study from the Lower Mekong basin. Our study area here is the combined basin of the Se Kong, Se San, and Sre Pok (3S) rivers which deliver approximately 20% of flow to the Mekong River system. We used a mixed methods approach to analyze potential impacts of climate change on regional hydrology, the ability of dam operation rules to keep downstream flow within acceptable limits, and the present state of water governance in Laos, Vietnam, and Cambodia. Our results suggest that future river flows in the 3S river system could move closer to natural (i.e. pre-development) conditions during the dry season and experience increased floods during the wet season. This anticipated new flow regime in the 3S region would require a shift in the current dam operations, from maintaining minimum flows to reducing flood hazards. Moreover, our Governance and Stakeholders survey assessment results revealed that existing water governance systems in Laos, Vietnam, and Cambodia are ill-prepared to address such anticipated future water resource management problems. Our results indicate that the solution space for addressing these complex issues in the 3S river basins will be highly constrained unless major deficiencies in transboundary water governance, strategic planning, financial capacity, information sharing, and law enforcement are remedied in the next decade. This work is part of an ongoing research partnership between the National Aeronautical and Space Agency (NASA) and the Conservation International (CI) dedicated to improving natural resources assessment for conservation and sustainable management.

How to cite: Mohammed, I., Bolten, J., Souter, N., Shaad, K., and Vollmer, D.: Assessment of water resources conservation and sustainable management strategies in the Lower Mekong River Basin, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1323, https://doi.org/10.5194/egusphere-egu22-1323, 2022.

Irrigated agriculture plays an important role in the continental water and energy cycles of the basins where it is present. Land-Surface models (LSM) can be used to study and quantify the impact of anthropic processes on the continental water cycle. Therefore, it is necessary to have good quality forcing and physiographic data, including a correct representation of agricultural covers, irrigation methods and actual irrigated areas. 

This work presents four datasets, at a spatial resolution of 1 km, that have been prepared to simulate irrigation-related processes using a LSM over the Ebro basin, the largest Mediterranean Spanish basin, where irrigated agriculture has a large impact on the water cycle. These datasets are: (1) a land cover map, (2) an actual irrigated areas map, (3) a map of irrigation methods per area, (4) and a meteorological forcing dataset.

The most recent version of the ISBA LSM, in SURFEX v9, contains an improved irrigation scheme (Druel et al., 2021), which requires the also recent ECOCLIMAP-SG land cover map (Druel et al., 2021). We validated ECOCLIMAP-SG over the Ebro basin, using SIGPAC data (Agricultural Plot Geographic Information System) provided by the Spanish Ministry of Agriculture, Fisheries and Food. The results showed low F1-score values, indicating a poor representation of agricultural covers. The comparison also showed that ECOCLIMAP-SG overestimated the irrigated surface. Therefore, it was decided to improve the ECOCLIMAP-SG Land Cover Map and create a new map of actual irrigated areas over this basin.

For the improved cover map, SIGPAC information was used. Each agricultural plot was classified, assigning to the informed cultivated species its correspondent ECOCLIMAP-SG cover and replacing it in the original map. The actual irrigated areas map was elaborated combining SIGPAC information of plots prepared for irrigation with data from LAI increments computed for two Summer days (20/08/2017 and 10/08/2019) by LDAS-Monde (Albergel et al. 2017). LDAS-Monde is a tool based on SURFEX able to assimilate satellite-derived LAI from the Copernicus Global Land service in ISBA. The irrigation method map was generated using a simple approach. The irrigation districts were classified between traditional and modernized. In traditional areas, the irrigation method was set to surface irrigation. In modernized areas, plots with herbaceous crops and trees were assigned to sprinkler and drip irrigation respectively. 

In addition, a new version of the SAFRAN meteorological forcing (Vidal et al. 2010, Quintana-Seguí et al, 2017), was developed. For this project, observations from two different sources (Spanish Meteorological State Agency and Catalan Meteorological Survey) were obtained, together with ERA5 data, which is used as first guess (for all variables except Precipitation). SAFRAN has been used to generate forcing data for Precipitation, Temperature, Wind Speed and Relative Humidity.  

The forcing dataset sensitivity has been tested by comparing two SURFEX simulations performed using the new SAFRAN forcing dataset, one with the original ECOCLIMAP-SG maps and another one using the new land cover, actual irrigated areas, and irrigation methods maps.

This work is a contribution to the LIAISE campaign, through the IDEWA project (PCI2020-112043).

How to cite: Barella-Ortiz, A., Quintana-Seguí, P., Dari, J., Brocca, L., Altés, V., Villar, J. M., Paolini, G., Escorihuela, M. J., Bonan, B., Calvet, J.-C., and Tzanos, D.: Improved SAFRAN forcing and ECOCLIMAP-SG datasets to simulate irrigation over the Ebro basin, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7834, https://doi.org/10.5194/egusphere-egu22-7834, 2022.

Calculating the drawdown of groundwater abstractions for drinking water is usually done considering the current land use and regional drainage characteristics. However, many drinking water abstractions already exist for several decades and abstracted volumes have increased over time. In the Netherlands, especially in the more elevated parts of the country, the drainage characteristics were also significantly altered to prevent water logging and to optimize the water management for agricultural use, often after establishment of the groundwater abstraction site. These changes were intended to lower the phreatic groundwater levels to prevent waterlogging, but unintendedly also made the regions more vulnerable to drought. The question is whether groundwater abstractions for groundwater would have a similar impact in the former historic hydrological context and whether restoring the system to this state would ameliorate current drought problems.

In this study we investigated whether a drinking water abstraction would have the same drawdown if the regional drainage characteristics would not have been altered and whether restoring the historic situation would decrease drought impacts. First, a literature study was conducted to understand the changes to the drainage system over time. These changes were then implemented in a regional groundwater model (based on Modflow) for a conceptual region, representative for the eastern part of the Netherlands. Results from both the literature study and the groundwater model indicated that changes in the drainage system lowered the groundwater levels by tens of centimetres (differences ranged from 20 to 100 cm). Drawdown from the drinking water abstraction was larger in the historical situation than in the current situation, even though groundwater levels were higher. In the historical situation less reduction in transpiration occurred, leading to a lower recharge of the groundwater and thus a larger drawdown. However, when irrigation was applied, this effect was not found.  This implied that a correct estimate of groundwater recharge is crucial to calculate drawdown from abstractions. Recharge depends on actual evapotranspiration, of which the conceptualization in regional models could be improved. Returning the drainage system to the historical situation leads to higher groundwater levels, thereby reducing the drought impact, but also increasing the risk of oxygen stress in crops. More research with regard to the impact on crop yields is needed on local scale, before measures to mitigate drought impacts can be taken.

How to cite: van Huijgevoort, M., Cirkel, G., and Bartholomeus, R.: Effects of historic changes in regional drainage characteristics on the drawdown of groundwater abstractions, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2333, https://doi.org/10.5194/egusphere-egu22-2333, 2022.

The city of Barcelona is severely affected by pluvial floods, for which the risk management can be further improved. To provide essential information about pluvial flood risk we compare two events that occurred in 1995 and 2018 and put these into context of all convective precipitation events between 2013 and 2018 in Barcelona. The objective is to identify the main drivers of pluvial flood impact and the most flood prone areas. These results will help to further improve pluvial flood risk management in Barcelona, e.g. by developing targeted preparedness and empowerment campaigns.

The event comparison followed the paired event approach (Kreibich et al. 2017). In the 1995 event, the surface runoff of the streets caused a fatality in the Eixample quartier, a total of 2,500 calls were registered to the emergency services, 128,000 subscribers suffered cuts of light, 2 blocks of houses were evacuated, and numerous low floors were flooded.  33.6 Million €₂₀₁₈ were paid by the national insurance company, CCS, to compensate insured losses in Barcelona. The 1995 episode marked a turning point in the development of the sewerage in the city. Although the maximum 5-min intensity in the 1995 event was 235 mm/h in front of 211 mm/h in the 2018 event, the maximum rainfall recorded in 20 min (155,4 mm/h versus 169,8 mm/h, respectively) and 60 min (78,6 mm/h versus 88,1 mm/h), as well as the “average water volume precipitated over the city” (376,5 m³ versus 457,1 m³) was superior in the second event. However, in the 2018 event, only 294 emergency phone calls were received, mainly due to flooding of low plants and basements, water leaks or fallen trees; and 3.5 Million €₂₀₁₈ were paid by the CCS. This analysis shows the effectiveness of the mitigation measures taken in the city after the 1995 flood event that have diminished the vulnerability. The analysis of the 207 convective pluvial events registered by the city's drainage network between 2013 and 2018, with a focus on the 58 events for which radar images are available (Esbrí et al., 2021) provides information on the city quartiers which are most endangered by pluvial floods. Conclusion shows that the structural and non-structural improvements applied in Barcelona are a good example for other cities with similar characteristics, although the improvement in awareness, empowerment and communication with the population is still pending, mainly in the most affected quartiers of the city.

This work has been done in the framework of the I-CHANGE (H2020-2020 Prop.101037193) European project and the C3-RiskMed (PID2020-113638RB-C22) research project, funded by the Spanish Ministry of Science and Innovation.

References.

Kreibich, H., S. Vorogushyn, J.C.J.H. et al. 2017. Adaptation to flood risk – results of international paired flood event studies. Special collection “Avoiding Disasters: Strengthening Societal Resilience to Natural Hazards” in the journal Earth’s Future. Earth’s Future,5,953–965, doi:10.1002/2017EF000606.

Esbrí, L.; Rigo, T.; Llasat, M.C.; Aznar, B. Identifying Storm Hotspots and the Most Unsettled Areas in Barcelona by Analysing Significant Rainfall Episodes from 2013 to 2018. Water 2021, 13, 1730. https://doi.org/10.3390/w13131730.

How to cite: Llasat, M. C., Aznar, B., Esbrí, L., Rigo, T., Grima, O., and Kreibich, H.: A comparative analysis between two pluvial flood events in Barcelona (Spain).  An example of a success story, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6604, https://doi.org/10.5194/egusphere-egu22-6604, 2022.

How to cite: Jonsson, E., Lindersson, S., and Di Baldassarre, G.: Global impacts of dams and reservoirs on hydrological droughts, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12594, https://doi.org/10.5194/egusphere-egu22-12594, 2022.

Drought is the natural hazard producing the most significant impacts on the agricultural sector. In the Mediterranean area, drought-related losses were estimated at approximately 9€ billion/year and this value is going to increase in future climate change scenarios. In this context, implementing proper risk reduction strategies and effective water resources management is fundamental in coping with drought-related water crises.

In this study, a survey has been proposed to farmers of the Po Valley (Northern Italy), in order to identify past drought and heatwaves events that hit their cultivations and to know the strategies implemented to cope with those events.

Farmers were asked to answer questions about the use of irrigation during past droughts and heatwaves, the preferred irrigation strategies during water crises (i.e., irrigate at night, irrigate a reduced area to full irrigation, crop prioritization, etc), the decisional criteria they adopted to establish when to start irrigation during a drought and the availability of insurance coverage.

Past droughts have been identified using the Standardized Precipitation and Evaponstrspiration Index (SPEI) and compared with the ones identified through the survey, highlighting two main drought events: the first one occurred in June 2003 and the other one in August 2019. This last event has been analysed in detail. Survey’s results reveal that, even if the 2003 event was more severe than that one in 2019, since all the farmers decided to irrigate their cultures during the 2003 drought, yield reduction was less than in 2019, when half of the farmers decided to not irrigate their crops during the drought event. In particular, the mean yield reduction for farmers who irrigated their crops during drought events was 35% less than for those who decided to not irrigate.

It was also found that droughts occurring in different plant growth stages have caused very different economic damages in terms of yield reduction, the amount of water resources allocated, and thus the irrigation expenses.

Regarding insurance coverage and the corresponding farmers’ grade of satisfaction, the survey’s responses revealed that farmers who applied irrigation didn’t acquire insurance coverages, and farmers who haven’t used irrigation trusted more on insurance.

How to cite: Bonaccorso, B., Borzì, I., Monteleone, B., and Martina, M.: A survey-based evaluation of farmers’ drought risk reduction strategies in the Po Valley (Northern Italy), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11981, https://doi.org/10.5194/egusphere-egu22-11981, 2022.

Water scarcity and drought are sustainability issues that cut across borders and different scales and levels of organizations and cannot be designated to one governmental authority. Due to hydrological droughts in semi-arid Northeast Brazil, the region deals with water scarcity. In the case of Ceará state, water is stored in multiple reservoirs as part of a water supply system and is managed from different levels of organization. These are considered governance scales that include state level-, regional level- and municipal level institutions, local level communities, and individual households. Water management in Ceará is an example of how polycentric governance brings a multifold of governmental and non-governmental actors together for the management of public goods in the society, and therefore cross-scale and cross-level interactions are inevitable. However, a variety of multiple challenges of contradictory water policies, diverse and varying levels of water users and multiple overlapping governance systems and organizations in combination with resource depletion make equitable water allocation challenging in Ceará. For this reason, this research aims to examine the scale mismatches in the water management processes and level misalignments of different governance levels and understand the influences of multiple governance systems on collectively managing water for equal water allocation. The following research question is used: What are the scale mismatches in water management and the misalignments of levels in water governance in Ceará state, and how have these affected the equitable access to water by different groups?

A polycentric governance lens is used to understand the interplay and influences of multiple water governance systems with competitive and cooperative relationships over water resources. We analyzed the multiple scale challenges in water management in the Banabuiú basin in the state of Ceará, using minutes from official water committee meetings, and qualitative data from interviews conducted with smallholder farmers, field technicians, civil servants and researchers in November and December 2021.

Literature research and fieldwork interviews in Ceará provided insights into user conflicts and mismatches across varying scales and levels. Our results show that, at river basin levels, e.g., networks of reservoirs and the river basin of Banabuiú, conflicts of prioritization between small-scale farmers and urban water users occur when the metropolitan area of Fortaleza is prioritized. Prioritization of the metropolitan region has been shown to result in limited and non-participatory decision-making, lack of information sharing and restrictions for irrigated farmers at the local scale. At the local scale, state interference in water management is in some cases not appropriate to the local context or in accordance with local knowledge. These scale mismatches occur due to multiple types of local water management, lack of responsibility for the management of monitored and unmonitored reservoirs, and various overlapping assisting agencies at the community level. The cross-scale interactions and conflicts in water management systems highlight the interdependencies between stakeholders and scale challenges in socio-hydrological systems. 

How to cite: van de Ridder, E., Cavalcante, L., van Oel, P., Dewulf, A., Kchouk, S., Ribeiro Neto, G., Walker, D., and Martins, E.: Polycentric governance and scale challenges in water management in the semi-arid river basin of Banabuiú, Ceará, Brazil, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6497, https://doi.org/10.5194/egusphere-egu22-6497, 2022.

Agricultural use of pesticides helps control a range of pests and diseases that threaten crops, thereby avoiding yield losses and improving the quality of the food produced. However, pesticides applied on agricultural fields dissipate with time. The export of pesticides and their transformation products after application from the agricultural fields threatens the water quality of aquatic systems in many world regions.

Climate change is further expected to intensify pest pressures and potential pesticide use by affecting agriculture in many ways. Changing climatic conditions can increase pesticide leaching due to increased and frequent rainfall, higher degradation rates, or higher temperatures or soil moisture contents. The indirect effects are changes in land use, the timing of crop cultivation, selection of other crop types, new pests and changed pest behaviour, etc. Additionally, several socio-economic factors influence pesticide use at the farm and national level, including regulation and legislation, economy, technology and crop characteristics. In order to better understand the pesticide risk to surface waters in the future, we aim to understand the influence of both climate and socio-economic change on pesticide use and fate.

Various catchment-scale models are available to assess pesticides and their impacts on water bodies. However, most modelling approaches solely concentrate on the total amount or concentration of pesticide exported from a catchment and do not necessarily analyse the future change of pesticide and transformation products. We propose an integrated modelling framework to answer the research questions: What are the current significant climate and socio-economic drivers influencing pesticide use and emissions? How can climate change influence pesticide and transformation products emission trends? How will socio-economic change influence pesticide emissions?

The integrated modelling framework helps to include adapting agricultural production to climatic (e.g., temperature, precipitation) and socio-economic drivers (e.g., land use, crop type, pesticide regulation) and quantifying pesticide emissions with the Zin-AgriTRA pesticide fate model. The ZIN-AgriTra is a catchment scale reactive transport model which can simulate agrochemical and transformation products exported from agricultural catchments. We use the Eur-Agri-SSP scenarios that extend and enrich the basic Shared Socio-economic Pathways with a regional and sectoral component on agriculture to explain the socio-economic change and climate projections for Representative concentration pathways to adopt climate change scenarios.

The integrated modelling framework links the future scenario results from independent, standalone models that present crop rotation, land use, pesticide regulation and climate to the pesticide fate model (Zin-AgriTRA). The framework is applied to an agricultural catchment in Burgenland, Austria, to quantify pesticide pollution under future climate and socio-economic change up to 2050.

How to cite: Nagesh, P., Gajraj, R., Eitzinger, J., and C. Dekker, S.: Modelling the impacts of climate and socio-economic changes on pesticide use and fate, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12615, https://doi.org/10.5194/egusphere-egu22-12615, 2022.