Reservoir operation is important to realize the coordination of social, economic and environmental systems. However, climate events have changed the water cycle process and the spatial-temporal distribution of the water resource system, which has brought new challenges to regional water resources management and reservoir operation. This study aims at analyzing the impacts of climate change on the multi-objective reservoir operation at the dry season, and the adaptive reservoir operation scheme for future climate change scenarios. The Jinsha River, at the upper reaches of the Yangtze River, was chosen as the research area because a large number of reservoirs have been built in the basin. Firstly, the Pettitt, MK and Moving t-test methods were used to identify the abrupt points of the hydro-meteorological data series from 1957 to 2018, and then the SWAT model was used to quantify the impacts of climate change on the runoff in the Jinsha River. Secondary, the multi-objective optimal operation model of cascade reservoirs was constructed, and then an improved PA-DDS method is developed to find the Pareto front between ecological protection and power generation. Thirdly, the impacts of climate change on reservoir operation were analyzed by comparing the scheduling results between the pre-change period (1957-1996) and the post-change period (1997-2018). Finally, using the Delta downscaling method, the GCM models chosen by suitability assessment were inputted into the SWAT model to simulate the future runoff for the reservoir operation model under different scenarios. The results showed that (1) the temperature and precipitation in the Jinsha River faced an abrupt change in 1997, while the runoff changed in 1997 and 2004. (2) the SWAT model can well simulate the daily runoff of Jinsha River (Re<15%, NSE>0.79, R²>0.8), while climate change accounts for 52.4% and 52.1% of runoff change during 1997-2004 and 2005-2018, respectively. (3) climate change can increase the ecological deviation degree and the power generation of reservoirs. In addition, compared with the traditional optimal scheduling scheme, the potential climate change brings higher requirements for water resources optimization in the future. (4) From 2021 to 2100, the temperature, precipitation and runoff of the Jinsha River are continually increased compared with the pre-changed period. It should be noted that the runoff from September and October is significantly reduced in most scenarios, increasing the insufficient storage risk of cascade reservoirs; man-made floods may be caused by the increasing runoff from April to June and the concentrated discharge of reservoirs before flood season. This study can provide theoretical support for reservoir operation and provide technical references for the impact mechanism of climate change on water resources and their management.

How to cite: Jia, W., Fu, G., Chen, M., and Wang, S.: Adaptive operation of reservoirs in the Lower reaches of Jinsha River at the dry season under climate change, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-3855, https://doi.org/10.5194/egusphere-egu23-3855, 2023.

Agricultural systems are adversely influenced by climate change through increased temperatures, change in run-off patterns and seasonality fluctuation. Farmers are, hence, a valuable source of first-hand observations of climate change as they may provide a deeper understanding of their manifestation and relevance. Farmers are aware of climate change impacts and promote adaptation measures such as changing crop varieties, adjusting planting dates, introducing agroforestry practices, and promoting soil and water conservation practices. However, some adaptation barriers persist such as the limited knowledge of potential adaptation strategies, high adaptation cost, or poor institutional support. Understanding why and how farmers aim to adapt to climate change is imperative to provide informed decisions to policy-makers and the first step to minimizing misconceptions or maladaptation practices. Consequently, drivers and influencing factors of farmers’ behavior toward climate change have received increasing attention in the last two decades.

Social and behavioral sciences have investigated the influence of farmers’ experiences in increasing climate change adaptation capability and improving decision-making processes at the system level, concluding how local perceptions provide sufficient baseline information for understanding individual and collective exposure to climate risks and risk aversion patterns, an essential element for effective policy formulation and implementation. Traditional management approaches based on simple, linear growth optimization strategies, overseen by command-and-control policies, have proven inadequate for effective adaptation to climate change. Conversely, accurate bottom-up approaches focused on social learning can complement the system transformation by building collaborative problem solving. In this line, associative processing methods, such as interviews and surveys, have been discussed for their ability to delve into knowledge-based data and monitor the nature, significance, and influence of personal experience on climate change adaptation.

Agent-Based Models (ABM) can include feedback between social and physical environments, define individuals’ narratives, and map the social network with agents’ interactions. This proposal aims at presenting a transdisciplinary approach that integrates survey data, with behavior and agrohydrological modelling in order to support policy-makers and managers to understand and re-think water management and climate change policies at the regional scale, which is essential to address climate change risks. From a system dynamics perspective, we characterize farmers’ risk aversion patterns and examine how ABMs can most effectively integrate these insights to increase robustness in decision-making processes while attending to farmers’ adaptive capacity. In the application to the case study of a large irrigated area in northern Italy, we surveyed 460 farmers to deepen a triple loop analysis on climate change awareness, perceived impacts, and adaptation measures and barriers. Statistics and computer-assisted data analysis were applied to gain insights from farmers’ profiles and risk perception. We included the profiles in an ABM coupled with a distributed agrohydrological model that covers the whole irrigated area. We expect farmers’ profiles influence agents’ risk perception and their ultimate decision on the adopted crop types and irrigation methods. Provisional results indicate that the approach can provide new insights across complexity in modelling farmers’ behavior and human adaptation to climate change and enrich the discussion about the gaps and benefits of including qualitative data in ABM.

How to cite: Ricart, S., Gazzotti, P., Ferrari, L., Gandolfi, C., and Castelletti, A.: Integrating farmers' risk aversion in climate change behavioral modelling to improve decision-making processes, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-4388, https://doi.org/10.5194/egusphere-egu23-4388, 2023.

Run of River hydropower plants (RoR) are characterised by a negligible storage capacity and by generation almost completely dependent on the quantity and variability of river flows. RoRs designed today will be deployed in a world characterised by a changing climate and uncertain economic conditions (electricity prices, interest rates, cost overruns). Investments need to be financially robust to these perturbations, but both design optimisation and robustness analyses traditionally incur large computing times and resources to explore a large range of potential futures. This hinders widespread uptake of these methods, and the emissions associated with large computing costs mitigate the environmental benefits of an otherwise renewable energy source.

Here we demonstrate a computationally inexpensive method for the optimisation (including multi-objective optimisation) and robustness analysis of run-of-river plants. It is based on the remark that the daily flow duration curve (FDC) can be approximated by a limited number of points, supporting a much faster evaluation of performance for a given FDC. Our method carries out the following steps:  (1) we approximate the daily FDC with N regularly spaced points, (2) we couple a multi-objective evolutionary algorithm with our state-of-the-art toolbox to optimise technical and financial indicators of performance, (energy production and economic profit) and generate design alternatives, (3) we sample uncertain factors to generate an ensemble of plausible future states of the World (SOWs), (4) we approximate the future FDC of each ensemble member with N points, (5) we quantify the robustness of selected alternative designs across the entire ensemble of SOWs.

We test our method with N=25, 50, 100, 250 and 500 points. We compare these results with traditional analysis (TA) done without approximating the FDC, and evaluated the trade-off between quality of results and required computational resources. Computational time required for performing optimisation with historical record (27 years of daily discharge) using 100,000 function evaluations is reduced by 98% and 92% for N = 25 and 500 respectively. The resulting Pareto optimal set has a good diversity and hypervolume performance for N ≥ 50 points is close (> 95%) to that of the set found by using 1,000 years of synthetic data for the optimisation. Likewise, the time required for analysing robustness across S = 500 SOWs is 98% less than TA in which we use an HPC platform and take 1,000 (synthetic stream flow) years into account. The performance evaluation of alternatives across the entire ensemble of SOWs is very similar to the robustness values based on TA. These preliminary results suggest that optimisation and robustness analysis can be performed with the proposed methodology for RoRs by using far less computational resources.

How to cite: Yildiz, V., Brown, S., and Rougé, C.: Computationally inexpensive robust design of run-of-river hydropower plants, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-5695, https://doi.org/10.5194/egusphere-egu23-5695, 2023.

As part of the Net Zero Carbon Water Cycle Program (NZCWCP) for Victoria state in Australia, we have sought to understand the potential to reduce household energy consumption and related Greenhouse Gas (GHG) emissions by influencing water use. Digital metering data disaggregated into 57 million discrete water usage events across 105 households at a resolution of 10 millilitres at 10 second intervals from June 2017 to March 2020, from a previous Yarra Valley Water (Melbourne, Australia) study, was analysed, together with the dynamic relationship between the multiple energy sources (natural gas, grid electricity, solar) used to heat water for showers in each hour of the day. Water-related energy (WRE) use, including water desalination and treatment, pumping, heating, wastewater collection and treatment, comprised 12.6% of Australia’s primary energy use in 2019. Water heating (by natural gas and electricity) comprised the largest component of WRE use for across residential, commercial, and industrial sectors. Furthermore, 69% of Victoria’s total water usage was by residential customers in 2020-2021. WRE GHG emissions were around 3.8% of Victoria’s total GHG emissions in 2018. Showers (~50% of residential WRE), system losses (~27% of residential WRE), and clothes washers (~9% of residential WRE) are the three largest components of WRE consumption. The main objective of this work is the creation of industry-accessible tools to improve knowledge and management options from the understanding of reductions in cost and GHG emissions from household showering WRE use. Potential options considered, to reduce water and energy use, as well as associated GHG emissions and customer utility bills, include (a) behaviour management such as water and energy pricing to change time of use behaviours, and (b) the adoption of efficient shower head improvements. Shower WRE and GHG emissions were found able to be strongly impacted by small changes in daily routines. GHG emissions reduction from showering could be reduced up to 20 (in summer) - 22% (in winter) by shifting demand time of showering or replacing residential showerheads. Extrapolated to state and Australian scales, reductions in water usage could be up to 14 GL (Victoria) and 144 GL (Australia), and reductions in GHG emissions 1,600 ktCO₂eq (Victoria) and 17,300 ktCO₂eq (Australia). It provides fundamental new information which could inform a suite of new management options to impact water-related energy from showers, and related GHG emissions and customer water and energy cost.

How to cite: Liang, X., Kenway, S., Bors, J., Radion, A., and Pamminger, F.: Potential Greenhouse Gas emissions reductions from simple changes to residential showering, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10136, https://doi.org/10.5194/egusphere-egu23-10136, 2023.

Inter- and intra-annual water availability is naturally highly variable in Mediterranean regions, with swings between extremes costing nations potentially billions of dollars in damages and threatening lives. In California, future projections foresee an increase in the bimodal distribution of hydrological extremes, leading to greater hydroclimatic whiplash. Here, we quantify the relative impact of hydroclimatic whiplash on hydropower systems, flood control and water deliveries in the Central Sierra Nevada, California. We aim to explore at what point these services become less resilient to drought, and if wet whiplash years can re-establish an ‘average’ system state. To represent a wide range of wet, dry and dry-to-wet transitions, we sampled water years from upper (floods) and lower (droughts) quintiles, with replacement, across 30 years of future streamflow projections (2030-2060) from 10 global circulation models. Synthetic hydrological sequences of 2 to 5 dry years, followed by 1 to 2 wet years form a total sample of 200 whiplash sequences for the Stanislaus, Tuolumne, Merced and Upper San Joaquin River basins. This stress test indicates that the intensification of whiplash cycles would seriously challenge existing hydropower production, water storage and flood control operating rules. Compared to baseline averages, all basins had negative impacts on hydropower generation, with losses varying from 6% in the Merced to almost around 67% in the Upper San Joaquin, depending on the whiplash sequence. Agricultural and/or urban demands are most impacted in the Tuolumne and the Upper San Joaquin, in particular for all sequences. Historically, this basin has had more than 70% of outflows delivered to irrigation districts, therefore whiplash sequences tend to disrupt these services more easily. Meanwhile, carryover storage is negatively affected in all basins, but more noticeably in the Merced and Stanislaus basins, with losses of 7-60% and 15-31%, respectively, due to their small overall storage capacity. The small reservoirs in the upper watersheds and inflexible operating flood control rules constitute a challenge to accommodate whiplash impacts in the region. These results show heterogenous sensitivities of flood control releases, environmental flows and agricultural/urban deliveries with projected climate whiplash conditions, with varying degrees of annual, time and volumetric reliability. These services compete for scarce water supply within the low-elevation terminal dams in each basin. This analysis identifies perspectives on the challenges and risks of regional climate whiplash effects and adaptation strategies to include extremes and their impacts on water allocation to human and environmental purposes.

How to cite: Facincani Dourado, G., Rheinheimer, D. E., Abatzoglou, J. T., and Viers, J. H.: Climate whiplash in California: too much to bear, too little to handle?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-10605, https://doi.org/10.5194/egusphere-egu23-10605, 2023.

Climate change and increased pressure on natural resources have been identified as some of the major challenges that will affect Europe in the coming decades. This will cause consequences such as migration, food price shocks, water scarcity and imbalances in energy markets. Food and energy security require large amounts of fresh water. Water is one of the essential resources in both sectors, acting as a crucial driver for irrigation. The demand for natural resources is likely to increase over the coming decades due to growing global population numbers and economic development. At the same time, climate change may lead to lower overall water availability. Consequently, water scarcity, variability and uncertainty are becoming more prominent, which could lead to vulnerabilities within the energy and food sectors. In this sense, The EU is promoting initiatives to address water scarcity, such as investments to improve water use efficiency and the reuse of wastewater for irrigation. The objective of this research is twofold. Firstly, we assess the impact of changes in irrigation water availability, crop water requirements and yields under climate change on EU agriculture. Secondly, we analyse how promoting the reuse of treated water for agriculture may contribute to the reduction of water stress in coastal areas.

Using agro-economic modelling (CAPRI), we implement climate change scenarios (RCP7.0 and RCP8.5) - taking into account not only yield changes but also changes in irrigation water availability and crop water requirements - to assess the impact of climate change on agricultural production and water stress across EU regions (NUTS2 regions). Furthermore, to capture the contribution of water reuse for irrigation to mitigate climate change impact on water scarcity, we simulate scenarios with increased treated water potential as an additional water supply at NUTS 2 level.

Results provide insights into how climate change impacts agricultural production, food prices and international trade. For example, irrigation water availability limitations with a reduction in crop yields in some heavily irrigated Southern regions could necessitate reversion of cropland from irrigated to rainfed management. However, climate change could lead to increased irrigated cropland in some less water stressed regions. The reuse of reclaimed water is an opportunity to favour the management and efficient use of water resources and can be a solution to water deficit problems. Model results reveal the potential of treated water as an alternative supply source to address water stress and promote sustainable water management under climate change in the EU provided that some conditions are met. It is necessary to invest in the construction of purification infrastructures in areas where there is no control of discharges, as well as in infrastructures that bring this water closer to the consumers. A price competitive with traditional water sources must be achieved in order for its use to become widespread. It is essential to achieve consumer acceptance of the product obtained through the use of reclaimed water, influencing farmers’ decision-making.

Acknowledgements:  This research has received funding from the European Union’s Horizon 2020 research and innovation programme under the GoNEXUS project (grant agreement No 101003722). 

How to cite: Arfa, I., Blanco, M., and González-Rosell, A.: Reusing reclaimed water for irrigation: sustainability solution to alleviate growing water scarcity under climate change?, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-14904, https://doi.org/10.5194/egusphere-egu23-14904, 2023.

To improve the effectiveness of water management policies aimed at water conservation, human behaviour and public preferences regarding water availability and supply are expected to play a key role but must be better understood. Water scarcity status can strongly influence stakeholders’ support for water resources management and significantly drive public willingness to pay (WTP) for water conservation measures. To account the full benefits of adopting conservation measures to improve urban water security, it is of paramount importance to understand what prevents people from investing in practices that protect and improve water yield in basins responsible for their water supply.

The main objective of this study is to inform water conservation programs in Brazil about public preferences for improving water security aspects (i.e., water supply and conservation measures) in the basins feeding water to urban city centers. To also test for possible influence of water scarcity experiences on public preferences for conservation measures and water security aspects, a choice experiment was carried out in two capital cities in Brazil that have faced different water restrictions and rationing efforts: the Metropolitan Region of Sao Paulo and Campo Grande city. We interviewed 400 people in each city in November 2021, and simple multinomial logit models using Apollo in R were used to estimate WTP for the reduction of the frequency and duration of future water shortages, as well as three different conservation practices: agroforestry, afforestation, and water harvesting technologies.

A model is estimated for each city, the Metropolitan Region of Sao Paulo (MRSP) and Campo Grande, as we wanted to test whether the different public experiences with water use restrictions and rationing lead to a different public WTP for water conservation measures. In both samples, the status quo alternative significantly decreased respondents’ utility, indicating an avoidance of the current water security status even though the respondents faced different water shortage experiences in each city. Twice as many residents in MRSP (77%) in the survey faced at least one episode of water restriction in the last decade than Campo Grande residents (36%). As a result, a decrease in the duration of water supply interruption has a significant effect on the respondents’ utility, considering the model estimated for the MRSP. In contrast, a reduction in the frequency of future water shortages was not significant. In Campo Grande, none of the attributes related to water security significantly impacted public preferences. Only the proposed measures had a significant influence on the utility of the respondents form Campo Grande. Our findings indicate that previous experiences with water scarcity affects not only the preferences for conservation initiatives, but also whether society perceives that these measures contribute to improving the water security. This study provides insightful information to policymaking for effective initiatives to improve water security with the involvement of society. Unveiling people’s preferences for water conservation practices and improvements in water availability and supply is fundamental to promote protection and conservation of water ecosystem services provided by river basins and, consequently, improve current and future water security.

How to cite: Sone, J., Wendland, E., and Brouwer, R.: Using choice experiment to inform water conservation initiatives under different water scarcity backgrounds to improve water security, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-15603, https://doi.org/10.5194/egusphere-egu23-15603, 2023.

California’s water storage and conveyance infrastructure—called the “water grid”—serves as a hedge against droughts. However, water operations—and more broadly the role of humans in reshaping drought risk and socio-environmental impacts—are usually not considered in characterizing drought status. The overall goal this project is to develop a framework for linking drought hazard indicators with sector-specific impacts in highly managed water storage and conveyance systems, such as those of the American West. To achieve this goal we have developed sector-specific drought hazard indicators for California that take into account water availability considering the built infrastructure, and management operations from both local and more distant water sources. After obtaining drought hazard indicators, we show case studies developing drought impact risk profiles for four sectors—agriculture, cities, small communities, and the environment—that reflect the capacity of these different sectors to respond and adapt to drought conditions.

One of the most innovative parts of this project is the co-development of decision support tools. Working with five different stakeholder advisory groups—science, agriculture, cities, small communities and environment—we are identifying the usefulness of the indicators, and thresholds and triggers that can be tailored for local, state, and federal drought response.

To conclude we will discuss the benefits and challenges of the current methodology, including data availability, the challenges associated with non-stationarity, and the co-development process with stakeholders.

How to cite: Escriva-Bou, A., Dettinger, M., Mount, J., and Rosser, A.: Developing Drought Indicators for Assessing Multi-Sectoral Impacts Using a Systems Approach, EGU General Assembly 2023, Vienna, Austria, 23–28 Apr 2023, EGU23-16758, https://doi.org/10.5194/egusphere-egu23-16758, 2023.