HS5.3

The human-generated systems typically meet biophysical ones within different geographical terrains. The space where those systems face each other is framed at the human-crafted and natural scales. Conventionally such sphere is a contestation field where various levels of contributing scales confront to embed a functional system. The water governing systems are as of the frequently debated of such systems. They resemble controversial evidence in the course of conflicts between hydrological and administrative/institutional scales. Indeed, due to the dominancy of human-determined objectives to the environmental requirements, the water governing systems have not considered reasonably the requisite of natural cycles in many areas. This issue produces externalities and mismatches between human-formulated and hydrological systems. To enhance the governance, there is a need to detect problems which arise from unfit of those systems in associated levels. Therefore, an inferential methodology which is able to capture and project the water (demand/supply) governing system state is being developed. The methodology encompasses incorporation of a system cost formulation approach. Besides, the system status in relation to microscopic configurations of its components is appraised through the method. This inscribed that a unique macroscopic state driven by a certain configuration is reflectable as a cost system bears in respect to its structure. Such cost is a theoretical estimate to measure the impact of a confiscated structure on the effectiveness of governing system. Correspondingly, the induced inefficiencies by the misfit between human-designed and biophysical systems are diagnosable through the comparison of system costs associated to pertinent structures/configurations.

How to cite: Arjomandi A., P., Seyedi, S., and Komendantova, N.: Water Governing Systems: addressing conflicts between hydrological and institutional scales, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4242, https://doi.org/10.5194/egusphere-egu22-4242, 2022.

Dams and reservoirs are crucial components for the water-energy-food (WEF) nexus but have major impacts on rivers and people. Future dams would compound impacts of existing dams and threaten so far undammed river systems. Recent research has highlighted threats from future hydropower dams and opportunities to reduce impacts through better infrastructure planning and proliferation of other renewable energy. Yet, while irrigation storage was a major driver for dam development in the past, the role of water storage in future food systems and the associated benefits and impacts has not been part of debates around future dams.

Here, we provide a global analysis that fuses global hydrologic modeling and infrastructure assessments to (1) quantify future demands for irrigation storage, (2) its role for food security, and (3) the contribution of existing and identified potential reservoirs to future irrigation. For that, we firstly analyze potentials for future sustainable (i.e., on existing croplands and without depleting environmental flows) irrigation and determine how much storage is needed to match water availability and crop water demand on a river basin level. Secondly, we quantify how much food could be grown with that water. Lastly, we perform a Monte-Carlo Analysis for all current and potential dams to robustly estimate possible water allocations from current and future dams to irrigation, and thus the role of this water infrastructure for global food security.

We find that future irrigated agriculture will require 460 km³/yr of water storage, 265 km³/yr on land that is already irrigated and 195 km³/yr on land that is currently rainfed. Much of that additional storage will be required in South Asia and West Africa. This storage-fed irrigation could grow enough food for 1.15 billion people. Yet even all current and future dams could only meet around 60 % of that potential.

Our results provide spatially explicit global information on (1) irrigation storage as important externality and cost factor for future food systems, (2) challenges for the WEF nexus in meeting concurrent demands for irrigation and hydropower, (3) the need to include irrigation in strategic impact/benefit assessments for future dams, and (4) urge to evaluate alternatives to large dams for future agricultural water storage.

How to cite: Schmitt, R. J. P., Rosa, L., and Daily, G.: Irrigation storage is a blind spot for analyzing and mitigating externalities of future water infrastructure, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6023, https://doi.org/10.5194/egusphere-egu22-6023, 2022.

Joint climate and land cover change can significantly alter catchment hydrologic response, e.g., in terms of runoff and sediment delivery, and thus key determinants for downstream hydropower outcomes. While many studies highlight climate risk for hydropower operation, it is less clear how climate and landuse change together will impact hydropower outcomes, if managing landuse can reduce those impacts, and how to prioritize effective investments in the face of uncertainty about the future climatic drivers.

In this study, we use Chaglla Dam, Peru’s third largest electricity generator, to develop an ensemble approach to identify parts of Chaglla’s contributing area with consistent changes in runoff and sediment under climate change. Those areas could then be targeted for maintaining or restoring natural land cover to increase baseflow and decrease sediment. We use SWAT to model catchment response for a large ensemble of climate trajectories based on latest CMIP 6 data, downscaled using multiple state-of-the-art algorithms and high-resolution regional weather observations (Figure 1 A and B). Based on the results, we identify parts of the catchment with greatest changes in water yield.  We find that 35 % of the watershed area shows consistent trends in water yield and sediment across all climate scenarios.

Climate risks will increase in the near and midterm future with increases the length of low-flow periods (up to 40 %) and increases in sediment (up to 17 %). Compared to that, additional changes in water and sediment because of projected land use change are relatively minor (+ 0.3 % in low-flow length and + 0.7 % in sediment).

Yet, our study introduces a spatially-explicit framework for analyzing large ensembles of climate and landuse projections to identify where future change will translate in most change in hydrologic parameters related to hydropower. Results enable to study if investing in catchment conservation in those areas will significantly improve hydropower outcomes and will thus help to develop management plans for hydropower catchment that are robust under future change.

How to cite: Ding, Z., Angarita, H., Montesino Cárceres, C., Lavado-Casimiro, W., David Barreto Escobedo, C., Guerrero, L., Zheng, H., and Schmitt, R.: Studying spatial agreement of catchment response to climate and landuse change under uncertainty for prioritizing investment into hydropower catchments, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6680, https://doi.org/10.5194/egusphere-egu22-6680, 2022.

Adapting water systems to climate is one of the most significant challenges. Nowadays, the research focus has been shifted from understanding climate change phenomena to studying its impacts on water resource systems in detail. Facing this challenge requires rigorous methodologies that increase the confidence in the climate models outputs, consider the physical complexity of our systems, and consider other factors such as population growth or the use of technologies enabling water saving.

This study presents a robust methodology to estimate climate change impacts on a complex water resources system, including changes in water consumption. It relies on a modelling chain involving climate, hydrological, and water resource system models. Future hydrological scenarios are generated by forcing a conceptual lumped hydrological model by bias-adjusted climate change CMIP5 scenarios. A joint meteorological-hydrological innovative process is used to assess and rank each scenario according to its performance in reproducing the climate and streamflow historical patterns and the streamflow change signal between two periods in a basin. Hydrological projections are used to feed a water resource system model, which includes the main physical and management complexities. By using this model, two complementary impact characterizations were defined: 1) assessing the impacts on the system only as a result of climate change; and 2) incorporating complexities inherent to the basin on top of climate change scenarios, such as the increase in water demand associated with population growth and the improvement in water use efficiencies after adopting better technologies.

This methodology is applied to the Turia River Basin (eastern Spain), a highly regulated system characterized by a strong variation in seasonal streamflows, intensive water use in urban and agriculture, and recurrent droughts. The system demands are supplied by surface and groundwater resources, water transfers from the neighboring Jucar river basin, and reclaimed wastewater reuse. The 18 available climate change trajectories from EURO-CORDEX for RCPs 4.5 and 8.5 were evaluated, and 12 were selected due to their satisfactory meteorological and hydrological performance. A water resources system model was built in the AQUATOOL Decision Support System (DSS) shell. We found that the entire water resources system could suffer significant adverse impacts even in the short term. Moreover, the projections show decreases in the water storage in reservoirs, increases in pumped water from aquifers, and increments in deficits to urban and agricultural demands. However, the methodology results also concluded that improvements in irrigation efficiencies in the Turia basin are an efficient measure to face the impacts of climate change.

Acknowledgements:

This study has been supported by the ADAPTAMED project (RTI2018-101483-B-I00), funded by the Ministerio de Economía y Competitividad (MINECO) of Spain including EU FEDER funds; the SÀPIDES project (INNEST/2021/276) funded by the Agència Valenciana de la Innovación (AVI), from the Generalitat Valenciana; and the Subvencions del Programa per a la promoció de la investigación científica, el desenvolupament tecnològic i la innovació a la Comunitat Valenciana (PROMETEO) under the WATER4CAST project.

How to cite: Lagos-Castro, I., Pulido-Velazquez, M., Macian-Sorribes, H., and Pedro-Monzonis, M.: Assessing the impact of climate and water demand change on hydrology and water resources in the Turia river basin, Spain, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9862, https://doi.org/10.5194/egusphere-egu22-9862, 2022.

The spatiotemporal variation of water resources and growing global requirements for freshwater necessitates planning and construction of water resource infrastructure to enable the management of a variable and potentially scarce resource. Large-scale water infrastructure serves multiple purposes including provisioning of freshwater, protection from floods, navigation, hydroelectricity, etc. At present, more than 16.7 million reservoirs with an area greater than 100 m² exist, a majority of which serve multiple water sectors. Decision analysis for reservoir systems relies heavily on optimization techniques that identify optimal operational strategies for a dynamic systems model. All optimization frameworks require the analyst to define performance indicators, more formally, objective functions, that aggregate performance across multiple time periods in a planning horizon. A question thus arises: does the manner in which objective functions are aggregated have a substantial impact on resultant optimal operational strategy? For complex reservoir systems such as inter-basin water transfers, which require coordinating operations across multiple reservoirs, the temporal scale of operations likely impacts the system's performance. Here, we assess the impact of temporal aggregation of the objective function on resultant operational strategies for a proposed inter-basin water transfer in Southern India. We optimize monthly water transfer decisions using a multi-objective evolutionary algorithm that optimizes for the reliability of demand satisfaction at multiple temporal resolutions (annual, seasonal, fortnightly). We then re-evaluate the performance of all resultant strategies at fortnightly resolution. We find strategies obtained by optimizing reliability at an annual resolution that release water based on annual demands outperform the other two resolutions. This improvement in performance requires the presence of additional storage structures like lakes, ponds, check dams, etc. in the reservoir system, which is true in our study region. We further quantify the dependency between decision variables across these formulations to better understand the convergence dynamics of the optimization algorithm.

How to cite: Veena, S. and Singh, R.: On temporal resolution of performance indicators of water resources systems, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12450, https://doi.org/10.5194/egusphere-egu22-12450, 2022.

Assessing the robustness of a water resource system to climate change involves exploring a range of streamflow conditions. For this, rainfall-runoff models are routinely to produce future streamflow, using as inputs either climate model projections or modified historical hydro-climatic conditions. However, these models have generally been calibrated and validated under historical conditions, and there is no guarantee that calibrated parameters would still be valid in a different climate. Indeed, recent literature suggests that rainfall-runoff models’ predictive skill decreases with changed climatic conditions especially when predicting drier climates. What is more, rainfall-runoff models require time, expertise and input data to calibrate and validate against the historical streamflow record.

With this abstract, we propose an alternative approach based on a near-universal parameterisation of flow duration curves (FDCs), and perturbation of these parameters to simulate a range of futures. Our method represents FDCs with a three-parameter function called the Kosugi model, which has been shown to provide an excellent approximation to FDCs under a wide range of climates. We directly relate these three parameters with three streamflow statistics that are of interest to water resource management: median, coefficient of variation, and first percentile. These values represent central tendency, variability, and low flow characteristics respectively. As a result, a broad range of changes in streamflow can be related to modified parameters, and our method goes through the following steps: (1) Kosugi model parameters are calibrated with a historical FDC, (2) a set of scenarios with modified flow statistics are determined, (3) a new set of coefficients of the Kosugi model are derived for each future scenario, (4) future scenarios are created by using these coefficients.

We apply this method to represent possible climate change impacts on the hydrology of seven headwater basins from different geographical and climatic conditions in Turkey. Preliminary results show that this method provides a dramatically large range of inflows, with increased frequency of high flows and low flows to better represent hydrological variability and extremes. This then supports robustness analyses for rivers for which no detailed hydrological model is available: here, on the financial viability of run-of-river hydropower design in a changing climate. The method supports time series with a large number of no-flow days.

How to cite: Rougé, C., Yildiz, V., and Brown, S.: Perturbing the flow duration curve to explore future flow conditions without a hydrological model, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10126, https://doi.org/10.5194/egusphere-egu22-10126, 2022.

Water scarcity is a serious socio-environmental challenge for sustainable development which is recognized as a potential cause of social conflict within and between countries. It is expected to intensify due to increasing water demands from increasing populations, rapid urbanization, industrialization, and climate changes. With predictions of dire global water scarcity, attention is turning to Unconventional Water Resources (UWRs) which are considered as supplementary water resources that need specialized processes to be used as water supply. The literature encompasses a vast number of studies on various UWRs and their usefulness in certain environmental and/or socio-economic contexts. Considering the increasing importance of UWRs in the global push for water security, the current study intends to offer a nuanced understanding of the existing research on UWRs by summarizing the key concepts in the literature. The number of articles published on UWRs have increased significantly over time and most publications were authored from researchers based in the USA or China, India, Iran, and Spain. Here, twelve general types of UWRs including fog, dew, rainwater harvesting, and cloud seeding as Atmospheric Unconventional Water (AUW); artificial recharge, fossil water as Unconventional Ground Water (UGW); iceberg water and virtual water as Transferred Unconventional Water (TUW), and wastewater, desalinated water, and agricultural drainage water as Processed Unconventional Water (PUW), were used to assess their global distribution, showing that climatic conditions are the main driver for the application of certain UWRs. Overall, the literature review demonstrated that, even though UWRs provide promising possibilities for overcoming water scarcity, current knowledge is patchy and points towards UWRs being, for the most part, limited in scope and applicability due to geographic, climatic, economic, and political constraints. Future studies focusing on improved quantitative documentation and demonstration of the physical and socio-economic potential of various UWRs could help in strengthening the case for some, if not all, UWRs as avenues for the sustainable provision of water.

Keywords: Water scarcity; UWRs; distribution maps; literature review

How to cite: Karimidastenaei, Z., Avellán, T., Sadegh, M., Kløve, B., and Torabi Haghighi, A.: Unconventional Water Resources: A golden opportunity to mitigate the mismatch between water supply and water demand, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-965, https://doi.org/10.5194/egusphere-egu22-965, 2022.

There are over 2,000 large reservoirs with a storage capacity greater than 1 million cubic meters (MCM) in the contiguous United States (CONUS). While many of these structures are documented in static datasets that include spatial locations and general characteristics (such as maximum storage capacity), there has previously been no comprehensive dataset of historical reservoir operations. To remedy this gap, we have assembled ResOpsUS, the first national dataset of historical reservoir operations. ResOpsUS contains historical time-series of storage, inflow, outflow, elevation, and evaporation data for 679 large reservoirs in CONUS. Here we use the unique ResOpsUS dataset to analyze storage trends over the last 40 years, identify potential causes of regional differences in reservoir variance and evaluate the relationship between meteorological drought and reservoir storage. Our preliminary analysis demonstrates that reservoir storage capacity in CONUS hit a limit in the early 1980s and no longer increased. Additionally, reservoir storage has decreased over the past 20 years with the magnitude of decrease greater in more arid regions.  Finally, correlations between precipitation and reservoir storage depict more direct relationships in wetter climates compared to drier climates where reservoirs are a necessary water supply during dry periods and thus storage in drier years may be higher than in wetter years.

How to cite: Steyaert, J. and Condon, L.: Historical analysis of large reservoir storage resilience and vulnerabilities in CONUS, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8944, https://doi.org/10.5194/egusphere-egu22-8944, 2022.

Water resources face global and local challenges. In Egypt, for example,  the negative impacts of climatic changes and the Grand Ethiopian Renaissance Dam (GERD), cause a shortage of water resources. Shortage of water resources is considered an urgent issue particularly in semiarid regions (like many MENA countries) and arid ones (like Egypt). Therefore, the Egyptian Ministry of Water Resources and Irrigation has launched the national project of canals rehabilitation and lining for effective water resource management and decreasing seepage losses. This study dealt with three different lining techniques, as well cracked-liner for the Ismailia canal, which is considered the largest end of the Nile in Egypt. A steady-state 2-D seep/w model was established for the Ismailia canal section, at the stretch from 28  to 49 km. The results showed that the amount of seepage was considerably depending on the hydraulic characteristics of the lining material. Pumping from aquifers through wells also has a significant influence on the seepage rate from the unlined canal. Nevertheless, a negligible effect was present in the lined canal case. The highest efficiency was obtained with the concrete liner, after that the geomembrane liner, and then the bentonite liner; with nearly 99%, 96%, and 54%, respectively, in the case of no pumping from aquifer via wells. The efficiency decreased by 4% for the bentonite and geomembrane liners during pumping from the aquifer, but the concrete liner efficiency did not change significantly. However, in the case of deterioration of the lining material through cracks, the efficiency strictly decreased to 25%, irrespective of the utilized lining technique. The dual effect of both cracked-liner material and extraction from the aquifer via pumping wells revealed an efficiency of 16%, regardless of the utilized liner type.

How to cite: Elkamhawy, E., Zelenakova, M., Straface, S., Vranayová, Z., Negm, A. M., Scozzari, A., and Abd-Elaty, I.: Seepage loss from unlined, lined, and cracked-lined canals: a case study of Ismailia canal reach from 28.00–49.00 Km, Egypt, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-13134, https://doi.org/10.5194/egusphere-egu22-13134, 2022.