Session HS1.1.11

[Programme]

HS1.1.11 | Hydrology under climate change: case studies on water availability, risk, and environmental outcomes

Hydrology under climate change: case studies on water availability, risk, and environmental outcomes

Convener: Gabrielle BurnsECSECS | Co-convener: Keirnan FowlerECSECS

Orals

| Thu, 18 Apr, 10:45–12:25 (CEST)

Room 2.31

Posters on site

| Attendance Fri, 19 Apr, 10:45–12:30 (CEST) | Display Fri, 19 Apr, 08:30–12:30

Hall A

In an era of climate uncertainty and evolving human influence on natural environments, understanding the dynamics of long-term climatic and hydrologic change has become critical. This session has a focus on real-world case studies and applications, though which we seek to explore the multifaceted implications of climate change on water availability, aquatic environments, and the dynamics of socio-ecological riverine systems.

We invite tangible examples of climate change impact assessments on hydrological and related systems, including resource management, policy and adaptation. We hope to showcase research across diverse geographical regions and varied contexts to facilitate sharing of methods, insights and lessons learned.

Submissions are encouraged across the full spectrum of available techniques, including so-called “bottom-up” approaches to decision making under deep uncertainty. Studies applying novel modelling paradigms, innovative risk assessment frameworks, or characterising multiple (compound) sources of risk are particularly encouraged. By showcasing diversity, we aim to foster a practical understanding of the implications of long-term change, leading to better decision-making for an uncertain future.

Orals: Thu, 18 Apr | Room 2.31

Chairpersons: Gabrielle Burns, Keirnan Fowler

10:45–10:55

EGU24-1628

solicited

On-site presentation

The potential impact of climate tipping points on drinking water supply planning and management in Europe

Peter van Thienen, Herbert ter Maat, and Sija Stofberg

In recent decades, substantial advancements have been achieved in state-of-the-art climate models, signifying commendable progress by the scientific community. These models have proven invaluable in comprehending and forecasting anthropogenic climate change. Nevertheless, their efficacy is limited when examining the intricate dynamics of tipping elements and their potential ramifications for overall climate stability. This limitation results in the absence of these tipping elements in widely adopted climate projections utilized by the drinking water industry to assess system resilience.

Despite the prevailing insufficiencies, there is a growing body of evidence indicating the existence and, conceivably, the imminent activation of certain tipping elements. The drinking water sector, characterized by its inherently slow-paced nature due to infrastructure designed for extended operational lifespans, faces a critical challenge. The rapid timescales associated with potential changes resulting from tipping element activations surpass the typical lifespan of drinking water infrastructure. Consequently, the water sector cannot afford to wait for scientific consensus to emerge.

This contribution asserts that climate tipping points pose a latent, underexplored, and potentially underestimated risk for the water sector. To address this concern, we introduce a straightforward model that explores potential magnitudes and timescales of abrupt climate changes linked to tipping element activations. Our investigation focuses on Europe, aiming to scrutinize the effects and consequences on drinking water supply. Specifically, we incorporate an assessment of the potential collapse of the Atlantic Meridional Overturning Circulation, deemed most pertinent for Europe based on projected effects, associated timescales, and implications for the water sector.

Our findings underscore the necessity of integrating tipping scenarios into the decision-making processes within the drinking water sector, given the profound uncertainty and far-reaching consequences associated with these events.

How to cite: van Thienen, P., ter Maat, H., and Stofberg, S.: The potential impact of climate tipping points on drinking water supply planning and management in Europe, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1628, https://doi.org/10.5194/egusphere-egu24-1628, 2024.

10:55–11:05

EGU24-14169

ECS

Virtual presentation

Hydrokinetic resource assessment for the Canadian Arctic

Koyena Bhattacharjee, Laxmi Sushama, and Julien Cousineau

Increasing renewable energy development has rekindled interest in hydrokinetic or in-stream river potential for power production using zero head turbines. This is also of interest for remote regions such as the Canadian Arctic where decentralized power production from renewable energy sources is an economically viable option in offsetting the high cost of diesel power production. However, one of the major obstacles is the absence of streamflow data at necessary spatial and temporal scales for these regions. This study estimates the hydrokinetic power potential for current-based systems in the rivers of the Canadian Arctic region, primarily Nunavut and adjoining regions, for the current and near-future periods, based on streamflow estimated using a routing scheme applied to runoff generated by ultra-high-resolution simulations of the Global Environmental Multiscale (GEM) model, for a high emission scenario. GEM simulation for current climate, validated against gridded and station observation data, suggest reasonable performance of the model, particularly streamflow-relevant variables such as precipitation, snow water equivalent, soil and air temperatures given improved representation of processes and surface heterogeneity due to the higher resolution. This is also reflected in the comparison of simulated streamflow characteristics with available observations from HYDAT.

Hydrokinetic power estimates over the study region show patterns similar to those of flow velocity as expected, with maximum hydropower being noted during the summer season for the central regions of Nunavut. Since the near-future period spans only till 2040, the changes in flow velocity and hydrokinetic power are minimal with an overall decrease of 2.5% for the southern and western regions of Nunavut and an increase of 2.5 to 5 % for some of the northernmost regions of Nunavut. The study further identifies ideal locations for the installation of hydrokinetic turbines for energy extraction, which require daily flow velocities above pre-defined thresholds, by considering indirectly also the impact of river ice on flow velocities. The results of this study provide useful information on hydrokinetic resources for the high-altitude regions of Canada by introducing a science-based approach and serve as a foundation for additional detailed investigations for site-specific studies to support the implementation of hydrokinetic energy conversion systems.

How to cite: Bhattacharjee, K., Sushama, L., and Cousineau, J.: Hydrokinetic resource assessment for the Canadian Arctic, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14169, https://doi.org/10.5194/egusphere-egu24-14169, 2024.

11:05–11:15

EGU24-7034

On-site presentation

Research informing policy to adapt to climate change: a case study from the Murray-Darling Basin, Australia

David Post

The Murray-Darling Basin in south-eastern Australia is one of the world’s largest rivers, draining an area of just over 1 million square kilometres. The basin drains about one-seventh of the Australian land mass and is the 16^th longest river in the world. However, being located on the driest continent on Earth, its discharge is relatively small, averaging just 767 m³/s, far smaller than the discharge from any other similarly sized river worldwide.

Despite the relative lack of water, the Murray-Darling Basin is one of the most significant agricultural areas in Australia. In 2008, the Murray-Darling Basin Authority was formed with a mandate to manage the basin in an integrated and sustainable manner. Water reform in the basin has been a world-first in terms of the scale of intervention, but it has led to numerous conflicts in terms of access to water. The ability to manage the basin adequately relies on appropriate research being carried out in order to determine how much water is currently available, where it is currently being used, and how water availability and use are likely to change into the future.

Climate change projections for the Murray-Darling Basin indicate a future that is likely to be hotter, with more frequent and intense droughts, accompanied by a reduction in cool season rainfall, particularly in the south of the Basin. As this is where the majority of runoff is generated, this is likely to lead to reductions in water availability, with a median reduction of around 20%.

The Murray-Darling Basin Plan was brought into force in 2012 and is due for review in 2026. CSIRO is carrying out hydroclimate research to assist policy makers to better understand the likely changes in water availability, and consequent adaptation options available to them. This presentation will summarise the likely climate change impacts on water availability and assess how best to deal with the uncertainties associated with these projections.

How to cite: Post, D.: Research informing policy to adapt to climate change: a case study from the Murray-Darling Basin, Australia, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7034, https://doi.org/10.5194/egusphere-egu24-7034, 2024.

11:15–11:25

EGU24-14318

On-site presentation

Balancing uncertainty when assessing climate change risk in large river basins: the case of the Murray Darling basin, Australia

Andrew John, Avril Horne, Keirnan Fowler, Ranju Chapagain, and Rory Nathan

Climate change threatens water resources from local to global scales. However, there are significant challenges in assessing climate risk for large river basins, especially those with multiple jurisdictions and competing management objectives. Traditional methods follow a top-down approach, where the impacts of climate projections by climate models are simulated using hydrological and water resource models. While these methods can provide a detailed snapshot of how rivers are impacted under a small number of projected future climates, their computational burden, and challenges in linking water resource models owned by different jurisdictions mean it is difficult to robustly explore the implications of aleatory (from hydroclimate variability) and epistemic (from hydroclimate change) uncertainty. Unlike top-down approaches, bottom-up approaches can be used to better understand vulnerability under a range of possible future climate. Bottom-up approaches begin with a sensitivity analysis of important management objectives to multiple hydroclimate stressors. Unfortunately, bottom-up approaches are constrained when using complex system models in large river basins, as their methodologies typically require many times more simulations than top-down approaches.

The Murray Darling basin (MDB) is Australia’s most significant river basin. Irrigation in the basin supports over $30 billion (AUD) in agriculture and livelihoods for the 2.4 million residents. The MDB has significant environmental values, with RAMSAR wetlands, many endemic and threatened species, and it is the traditional land of over 50 first nations groups. We assessed the impacts of climate change on basin-wide inflows and key indicator sites using both top-down and bottom-up approaches. We stochastically generated multiple sequences of future hydroclimate conditions, which helps separate the influence of climate variability from climate change. We deliberately traded-off detail in our assessment by deriving simple functional relationships between sub-basin inflows and 21 key indicator sites using existing scenarios from the complex jurisdictional water resource models. This allowed us to assess far more replicates of stochastic data, more climate scenarios, and conduct a more rigorous stress test within the bottom-up framework than would normally be permitted using complex models.

The top-down approach provides a scenario-based assessment of likely conditions for water resources in the MDB, and spatially coherent projections of future inflows and river management metrics. The bottom-up approach provides more insight into spatial differences in sensitivity across the river catchments that make up the MDB, and can be used to both augment and help interpret outcomes from the top-down approach. The bottom-up approach also yields important thresholds in hydroclimate conditions which compromise basin-wide objectives (assessed through flow at the Murray River mouth which prevents the important lower lake system from becoming too saline). We consider top-down and bottom-up approaches to be complementary in assessing and adapting river systems to the impacts of climate change.

The simple methods used here are complementary with other more detailed impact models. The ease of undertaking simulations and computational efficiency means simple methods can filter down the range of possible conditions or stressors that contribute to uncertainty, allowing a more targeted set of simulations to be undertaken using detailed, but costly, water resource models.

How to cite: John, A., Horne, A., Fowler, K., Chapagain, R., and Nathan, R.: Balancing uncertainty when assessing climate change risk in large river basins: the case of the Murray Darling basin, Australia, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14318, https://doi.org/10.5194/egusphere-egu24-14318, 2024.

11:25–11:35

EGU24-612

ECS

Virtual presentation

Assessment and projection of food security related ecosystem services in Nakhon Phanom, northeastern Thailand

Hoang Minh Nguyen and Huu Loc Ho

11:35–11:45

EGU24-11923

ECS

On-site presentation

Using water use models to project long-term trends of water supply and demand equilibriums under climate change: application to the French Loire River basin.

Camille Debein, Victor Vermeil, Raphaël Lamouroux, Céline Monteil, Frédéric Hendrickx, Fabrice Zaoui, and René Samie

The French Loire River basin (81,000 km²) is characterized by a wide range of water uses (energy production, irrigation, drinking water supply, industrial processes, navigation, etc.). Recurring droughts and periods of low flow in the basin have emphasized the vulnerability of certain ecosystems and water uses in relation to the available resources. In addition, the prospect of global and local changes (climate change, changes in uses and territorial dynamics, etc.) added to evolutive environmental policies are expected to impact the availability of water resources in the upcoming years.

Within this evolving context of resource availability, we propose a quantified projection of future changes in the water supply-demand balance within the Loire River basin for two future timeframes, 2035-2065 (mid-term) and 2070-2099 (long-term), relative to the current climate (1976-2005). To achieve this, a modeling framework encompassing catchment-scale representations of climate, natural resource distribution, and primary water uses (energy, irrigation, drinking water supply, and industry) has been developed. Spatial and temporal heterogeneities are accounted for with a semi-distributed hydrological model [1] (using sub-catchment meshes of nearly 100 km²) and a daily time-step. This framework builds upon previous hydrological studies [2] and enables the representation of impacts on resource availability resulting from both natural and anthropogenic forcing variables.

Initially validated over the historical period (1976-2005) through comparison with national discharge monitoring networks and water use databases, this modeling chain was fed with data from four climate evolution trajectories taken from the Explore2 project that outline contrasting storylines of climate changes over the Loire basin. Simulation results reveal a decrease in water resources and an increase in global water demand, particularly in summer, correlating with increasing average air temperature and the relative reduction of precipitation. Evaluation of water stress indicators [3] suggests that tensions between water supply and demand will become increasingly frequent and more intense, particularly in summer.

This work emphasizes the interest of coupling water use modeling with hydrological simulations and advocates for evaluating the impact of changes in the territory (such as socio-economic or land use dynamics) on the resource.

Figure 1. Schematic representation of the modeling chain involved in quantifying the supply-demand balance.

(A) (B)

Figure 2. Spatial heterogeneity of the Blue Water Stress (A) and the Blue Water Scarcity (B) indicators [3] evaluated over the considered catchment area of the Loire River (august 2070-2099 for the “hot and humid” Explore2 climate trajectory, RCP 8.5).

References:

[1] Rouhier, L., Le Lay, M., Garavaglia, F., and Le Moine (2017). Impact of mesoscale spatial variability of climatic inputs and parameters on the hydrological response. Journal of Hydrology, 553, 13-25.

[2] Samie, R., Monteil, C., Arama, Y., Bouscasse, H., and Sauquet, E. (2014). La prospective territoriale, un outil de réflexion sur la gestion de l’eau du bassin de la Durance en 2050. Hydrology in a Changing World: Environmental and Human Dimensions, 221.

[3] Wang, Dan, Klaus Hubacek, Yuli Shan, Winnie Gerbens-Leenes, and Junguo Liu. (2021). "A Review of Water Stress and Water Footprint Accounting" Water 13, no. 2: 201.

How to cite: Debein, C., Vermeil, V., Lamouroux, R., Monteil, C., Hendrickx, F., Zaoui, F., and Samie, R.: Using water use models to project long-term trends of water supply and demand equilibriums under climate change: application to the French Loire River basin., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11923, https://doi.org/10.5194/egusphere-egu24-11923, 2024.

11:45–11:55

EGU24-3325

ECS

On-site presentation

Snow cover and snow water equivalent dynamics in the Upper Indus Basin (UIB) under current and CMIP6 climatic projections

(withdrawn)

Aftab Nazeer*, Muhammad Asif, Azhar Inam, and Muhammad Asif

11:55–12:05

EGU24-12009

ECS

Virtual presentation

Flood envelope curves for the estimation of design flood magnitudes for highway bridges

Dona Maria and Laxmi Sushama

The rising costs and safety concerns associated with flood-induced infrastructure damages in Canada underscores the critical need for adapting design flood magnitudes to future climate change. Creager flood envelope curves, which serve as the upper bound/limit of observed extreme flows for different drainage areas within a specific region, are widely employed by practitioners to estimate design flood magnitudes, which in the case of most river-crossing highway bridges is considered as 75-year flood magnitude. A framework for adapting Creager curves to future changes in streamflow is proposed in this study. To this end, Creager curves, for the current 1951–2020 period, are developed using regional frequency analysis (RFA) on annual maximum daily mean streamflow, considering 417 observation stations, located in seven major Canadian river basins (i.e., Fraser, Nelson, Mackenzie, Yukon, Churchill, St Lawrence and St John). The Creager coefficient C, which is the main parameter that defines flood envelope curves for different regions, under the current climate, exhibits considerable variability, ranging from 1 to 45, across the studied river basins.

To adapt Creager curves for future changes, a correction factor, R_C, defined as the ratio of future to current period C values is proposed. Two RFA approaches were employed to calculate the ratio using simulated streamflow data, derived using a cell-to-cell routing scheme, applied to an ensemble of five-member Regional Climate Model (RCM) GEM (Global Environmental Multiscale) simulated runoff for the current reference 1951–2020 and future 2021–2099 periods for the observation sites. The first RFA approach, considering only the GEM grid cells where the stations are located, suggests R_C in the 0.3 to 1.6 range, with St John and St Lawrence River basins showing values less than 1. The second approach, considering all GEM cells for a given region, produces comparable results but yields a wider range for R_C and adds useful information in that R_C values can also be established at ungauged locations, with R_C values higher than 1.6 in various regions especially over western Canada. An evaluation of the level of confidence for R_C , based on the GEM ensemble, reveal a higher level of confidence for most parts of the study domain. The second approach is likely to be a better choice for longer return periods considering the larger pooling of data. From a practical viewpoint, the proposed method for estimating future design floods is robust and transferrable to other basins but can benefit from using streamflow projections from other models for better quantification of uncertainty.

How to cite: Maria, D. and Sushama, L.: Flood envelope curves for the estimation of design flood magnitudes for highway bridges, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12009, https://doi.org/10.5194/egusphere-egu24-12009, 2024.

12:05–12:15

EGU24-11231

ECS

On-site presentation

Assessing Climate Change Effects on Hydrology in the Ave catchment, Portugal: A Comparative Analysis of Various Shared Socioeconomic Pathways (SSPs)

Morteza Zargar, Tim G. Reichenau, Zryab Babker, and Karl Schneider

Climate change can pose a significant threat to water fluxes on terrestrial surfaces, impacting water availability, and increasing the risk for human-environment systems to floods and droughts. Understanding the repercussions of climate change on future water resources is imperative for effective integrated water resources management. As part of the DISTENDER project (EU Horizon-ID 101056836), we scrutinize the effects of climate change on diverse watersheds in Europe to develop strategies for climate change adaptation.
To simulate the impacts of climate change on water resources, we chose MIKE SHE for its spatially distributed and physically based modeling concept. Here we present the results of different climate models vs. SSPs on water balance components and runoff for the Ave River Basin in Northern Portugal. MIKE SHE was calibrated and validated utilizing measured gauge runoff data from 1980 to 1986 and 1986 to 1990, respectively. For the various gauges, Nash-Sutcliffe efficiencies between 0.59 and 0.81 were achieved.
Statistically downscaled climate change projections for the period (2021-2050) from the Coupled Model Intercomparison Project Phase 6 (CMIP6) were used as input to MIKE SHE. We used three different climate models (CanESM5, EC-EARTH3, MPI-ESM1-2-HR) and four shared socioeconomic pathways (SSPs 1-2.6, 2-4.5, 3-7.0, 5-8.5) each. Hydrological variables were evaluated for each of the twelve-climate model runs in comparison to the reference period (1980-2010).
All climate simulations show an increase in annual precipitation, except for CanESM5 SSP 3-7.0, MPI-ESM1-2-HR SSP 2-4.5, and MPI-ESM1-2-HR SSP 3-7.0. The precipitation increases range from 1 % to 24 %. This underscores the impacts of different SSPs and climate models on projected regional precipitation patterns and emphasizes their importance in comprehensive climate change assessments.
In all scenarios, the projections indicate an increase in flood for different durations (1-day, 3-days) at all gauges across different return periods. The flood increase calculated for the three different climate models exhibits greater differences than the flood increase calculated for different SSPs across climate models. For example, in the Ave River, the range of the 100-year flood across SSPs varies from 81 m³/s (Min: 432m³/s, Max: 513 m³/s) for MPI-ESM1-2-HR to 225 m³/s (Min: 496 m³/s, Max: 721 m³/s) for EC-EARTH3. The corresponding range across models spans from 71 m³/s (Min: 425 m³/s, Max: 496 m³/s) for SSPs 3-7.0 to 213 m³/s (Min: 508 m³/s, Max: 721 m³/s) for SSPs 5-8.5. The 100-year flood (1-day duration) in the reference period value is 372 m³/s. In addition, the duration of low-flow events increases significantly for most climate scenarios. This increase in extreme events, which includes both, an increase in the volume of floods and an increase in the duration of droughts, emphasizes the need for proactive measures to address and adapt to the anticipated changes in hydrological patterns due to climate change.
However, our findings show that the selection of the climate model has a great impact on the hydrological variables. Decision-makers should carefully choose a climate model aligned with their planning objectives, considering the potential risk for robust planning.

Keywords: Climate change, CIMP6 Climate Model, MIKE-SHE, Ave catchment

How to cite: Zargar, M., Reichenau, T. G., Babker, Z., and Schneider, K.: Assessing Climate Change Effects on Hydrology in the Ave catchment, Portugal: A Comparative Analysis of Various Shared Socioeconomic Pathways (SSPs), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11231, https://doi.org/10.5194/egusphere-egu24-11231, 2024.

12:15–12:25

EGU24-3204

ECS

On-site presentation

Sustainable water management in Southern Ecuador: water availability under climate change and adaptation strategies.

Ana Ochoa-Sánchez, Patricio Crespo, Patrick Willems, Rolando Célleri, Pablo Guzmán, María Alvarado-Carrión, Johanna Ochoa, Jorge García, Santiago Núñez, Verónica Rodas, Rigoberto Guerrero, María Augusta Marín, and Gabriela Sánchez

Anthropogenic climate change together with non-climate drivers (e.g land use change) have affected natural and human systems in the Andean Mountain region. There is more evidence of changes in water systems, with decreasing water availability and increasing frequency and magnitude of extreme events (i.e. flooding and droughts). This region is especially vulnerable to climate change and faces challenges towards adaptation due to limited resources and policies. Therefore, we present an integrated water management (IWM) approach to secure water availability in a middle-size city in Southern Ecuador - Cuenca. The Andean city of Cuenca (~ 600 000 inhabitants, located at 2600 m a.s.l.) depends highly on precipitation and surface water from the highlands to ensure drinking water. Due to its complex orography, climate change projections are not yet available at an adequate resolution for local decision making and limited actions and plans towards adaptation are undertaken. Our IWM approach, then, involves two phases:

(1) Quantifying water availability projections. Statistical and dynamical downscaling techniques are used to quantify climate change projections at 1 km resolution for the study area, together with indicators useful for decision-makers. Discharge projections are quantified by using conceptual and distributed hydrological models. In parallel, water consumption is monitored and projected. Finally, we find water availability projections towards 2100.

(2) Constructing adaptation strategies. On the provision side, water management improvements are co-constructed with the local drinking water company (ETAPA EP), such as: evaluating old infrastructure (e.g. leaks control), proposing new green-blue and gray infrastructure. On the demand side, strategies to reduce water consumption are co-constructed and implemented within a pilot project that involves citizens from three neighbourhoods in Cuenca.

Our study involves a variety of actors and sectors (i.e. Ecuadorian and Belgian Universities, decision- and policy makers and citizens), enhancing capacity building of local governments and transferring knowledge among Universities and institutions, to plan and implement adaptation strategies through bottom-up approaches. We expect that our approach can be used in other middle-size cities, with similar challenges or complex orography conditions.

How to cite: Ochoa-Sánchez, A., Crespo, P., Willems, P., Célleri, R., Guzmán, P., Alvarado-Carrión, M., Ochoa, J., García, J., Núñez, S., Rodas, V., Guerrero, R., Marín, M. A., and Sánchez, G.: Sustainable water management in Southern Ecuador: water availability under climate change and adaptation strategies., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3204, https://doi.org/10.5194/egusphere-egu24-3204, 2024.

Posters on site: Fri, 19 Apr, 10:45–12:30 | Hall A

Display time: Fri, 19 Apr 08:30–Fri, 19 Apr 12:30

Chairpersons: Gabrielle Burns, Keirnan Fowler

A.8

EGU24-7932

ECS

Vegetation restoration potential in the drylands of China under water constraint

Huiqing Lin and Yan Li

As an essential pathway for nature-based solutions, vegetation restoration can effectively absorb carbon sequestration and mitigate global warming. However, the excessive water consumption by vegetation expansion may create potential water conflicts between natural ecosystems and human systems, and even exacerbate local water shortages, especially in water-limited dryland regions. By evaluating water availability using multiple datasets, this study explored the vegetation restoration potential and the allowable vegetation conversion in China’s drylands under the constraint of water availability. We found that the additional water resources available for vegetation restoration in China’s drylands were 12 ± 114 mm (median ± SD) from 2003 to 2018 but it decreased over the period (-1.18mm/year). 43.3% of the dryland area had water deficits, after considering current vegetation and human water consumption. Under current water constraints, additional Gross primary productivity (GPP) that could be restored ranged from 8% to 12% depending on vegetation types (10.5% for forests, 11.6% for grasslands, 7.8% for irrigated crops, and 8.9% for rain-fed crops). In water surplus areas, primarily in the south and east of China’s drylands, most vegetation conversions toward higher-water-consumption types were allowed to occur. In water deficit areas, the west of drylands, even converting all the existing vegetation to less water-intensive types would not compensate for the water deficit in most regions, suggesting local vegetation may have exceeded the water-carrying capacity. Our research highlights the importance of the potential water constraint of vegetation restoration in drylands and provide a guidance for decision-making vegetation restoration while ensuring water sustainability. Next, we will explore the potential for vegetation restoration under different climate change scenarios (e.g., ssp126, ssp370, and ssp585).

How to cite: Lin, H. and Li, Y.: Vegetation restoration potential in the drylands of China under water constraint, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-7932, https://doi.org/10.5194/egusphere-egu24-7932, 2024.

A.9

EGU24-19003

ECS

Land cover planning strategies and Water Use Optimization of a Mediterranean Basin Under Climate Change

Serena Sirigu, Roberto Corona, Adriano Ruiu, Riccardo Zucca, and Nicola Montaldo

Over the past century, climate change has been affecting precipitation regimes across the world, and in the Mediterranean regions there is a persistent declining trend of precipitation and runoff decreases contributing to a desertification process with dramatic consequences for agricultural and water resources sustainability. Climate change projections point to an amplification of changes in global precipitation patterns and trends, with further drier trends for the Mediterranean area. These trends will have dramatic consequences on water resources for both managed (e.g., agricultural) and natural systems. In Mediterranean climates during the winter months much of the precipitation recharges sub-surface and surface reservoirs. In particular, in Mediterranean regions a strong decreasing trend of winter precipitation and an evident shift in how the precipitation is distributed across the winter and spring months is estimated. Considering that most of the runoff to surface reservoirs occurs in the winter months and that spring hydrologic response is likely to be influenced strongly by vegetation, these precipitation changes can be considered hydrologically important. Case study is the Flumendosa basin (Sardinia), which is one of the case studies of the ALTOS European project, characterized by a reservoir system that supplies water to the main city of Sardinia, Cagliari. Data are from 42 rain gauges stations (1922-2023 period) over the entire basin and data of runoff are available for the same period. In the Flumendosa reservoir system the average annual input from stream discharge in the latter part of the 20th century was less than half the historic average rate, while the precipitation over the Flumendosa basin decreased, but not at such a drastic rate as the discharge, suggesting a marked non-linear response of discharge to precipitation changes. We developed and calibrated a distributed hydrological model at basin scale which predicts runoff, soil water storage, evapotranspiration and grass and tree leaf area index (LAI). Hydrometeorological variables provided by the future climate scenarios predicted by Global Climate Model (CMPI-6 MPI-ESM1-2-LR downscaled) have been used as input in the model to predict soil water balance and vegetation dynamics under the future hydrometeorological landcover scenarios. The historical observations highlighted strong negative trends in precipitation series and number of wet days (examined using the Mann-Kendall trend test). The results from model application showed that tree dynamics are strongly influenced by the inter-annual variability of atmospheric forcing, with tree density changing according to seasonal rainfall. At the same time the tree dynamics affected the soil water balance. We demonstrated that future warmer scenarios would impact forest, which could be not able to adapt to the increasing droughts. In the Flumendosa basin future scenarios predict a reduction of the runoff, which is crucial for the dam reservoir recharge. The water resources system planning needs to carefully takes into account the effect of future climate change on water resources and vegetation dynamics.

How to cite: Sirigu, S., Corona, R., Ruiu, A., Zucca, R., and Montaldo, N.: Land cover planning strategies and Water Use Optimization of a Mediterranean Basin Under Climate Change , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19003, https://doi.org/10.5194/egusphere-egu24-19003, 2024.

A.10

EGU24-5789

ECS

Understanding the uncertainty in the climate and water resource availability interplay: a distributed analysis of the Italian territory

Alessandro Amaranto, Leonardo Mancusi, and Giovanni Braca

As the tangible impacts of climate change continue to unfold, the imperative to assess and prepare for its repercussions on water resources becomes increasingly evident. This study addresses the urgent necessity to foresee future scenarios of surface water availability in Italy, recognizing the crucial role of water in sustaining ecosystems, agriculture, and human life. To unravel the intricate interplay between climate change and water availability, our methodology integrates the three representative concentration pathways (RCPs) from the Intergovernmental Panel on Climate Change with six regional circulation models. This combination projects future trajectories of temperature and precipitation. Utilizing the time-varying quantile mapping downscaling technique, we refine these trajectories for enhanced spatial and temporal resolution (1 km). These downscaled data feed into the water balance model BIGBANG, developed by the Italian Institute for Environmental Protection and Research (ISPRA), facilitating the generation of the spatiotemporal distributions of surface water availability across Italy. A probabilistic analysis offers a nuanced understanding of potential future water scenarios. Our findings highlight the profound influence of emission scenarios on water availability's future trajectory. Under maximum adaptation conditions (RCP 2.6), a relatively stable water availability pattern is projected through the century. Conversely, the business-as-usual scenario predicts a significant decrease of up to 50% in surface water availability, particularly in historically drought-prone southern regions of the country. These results underscore the critical importance of proactive adaptation measures to mitigate the potential impacts of climate change on Italy's water resources.

How to cite: Amaranto, A., Mancusi, L., and Braca, G.: Understanding the uncertainty in the climate and water resource availability interplay: a distributed analysis of the Italian territory, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5789, https://doi.org/10.5194/egusphere-egu24-5789, 2024.

A.11

EGU24-2135

ECS

Assessment of Climate Change on Water Availability in Central Himalayas, Nepal

Bipin Dahal, Insaf Aryal, Naba Raj Dhakal, and Suresh Marahatta

The Kaligandaki River Basin (KRB) in Nepal, as one of the Himalayan River Basins, is experiencing severe impacts of climate change on its water resources. In this study, future climate projections from downscaled CMIP6 GCM models were used to evaluate the potential effects of climate change on the hydrological regime of the KRB by developing a hydrological model soil and water assessment tool (SWAT). Multi-site validation approaches were used to address the high spatial heterogeneity of the basin. The performance of the model was excellent, achieving a consistently very good ranking throughout the study, as evidenced by calibration and validation results. Under the intermediate emission pathways SSP245 scenario, the average annual temperature in the basin is projected to increase by 1.5°C, with a maximum rise of 2.8°C during the pre-monsoon season in the far future. In the high emission pathways SSP585 scenario, the average annual temperature is projected to increase by 2.2°C, with a maximum rise of 4.3°C expected during the winter season in the far future. Precipitation is anticipated to increase across all future time windows, with higher magnitudes under the SSP585 scenario. The combined effect of temperature and precipitation increases is expected to increase the discharge of the river. Specifically, discharge is projected to increase by 6% (under SSP245) and 12% (under SSP585) for 2025-49, 14% (under SSP245) and 24% (under SSP585) for the 2050-74, and 23% (under SSP245) and 40% (under SSP585) for the 2075-99 timeframes. The projected changes indicate an overall increase in average annual discharge, with greater increases expected under the high-emission scenario. These findings highlight the significant influence of climate change on the water balance components and hydrological regime of the KRB.

Keywords: SWAT, Climate Change, Water Availability, Kaligandaki

How to cite: Dahal, B., Aryal, I., Dhakal, N. R., and Marahatta, S.: Assessment of Climate Change on Water Availability in Central Himalayas, Nepal, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2135, https://doi.org/10.5194/egusphere-egu24-2135, 2024.

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A.12

EGU24-2241

ECS

Global vulnerable basins suffering social-ecological impacts of water scarcity

Fubo Zhao and Yiping Wu

The UN water conference, convened in March 2023, calls for governing water and addressing climate change in tandem to co-achieve related sustainable development goals. However, the actual (water scarcity under current climate conditions) and potential (potential water scarcity under climate change) impacts of water scarcity on social-ecological impacts are rarely assessed. Herein, we developed a framework that integrates water scarcity and climate sensitivity to assess the socio-ecological vulnerability of global basins. We found that basins that already experience water scarcity are exhibit a disproportionate magnitude of climate sensitivity, which exacerbated the challenges associated with water resources management. We identified the vulnerable basins by integrating socio-ecological vulnerability and found that the most vulnerable basins are mainly located in developing countries. Therefore, the urgent international cooperation for reducing vulnerabilities of water scarcity is required. Measures involved in current Integrated Water Resources Management and Climate Change Adaptation may not be enough to alleviate the water crisis and to adapt to climate change in these vulnerable basins. We thus urge policy makers in regions suffering vulnerable water scarcity to integrate both approaches to manage water and climate in tandem and synergistically achieve related sustainable goals.

How to cite: Zhao, F. and Wu, Y.: Global vulnerable basins suffering social-ecological impacts of water scarcity, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2241, https://doi.org/10.5194/egusphere-egu24-2241, 2024.

A.13

EGU24-16678

Using a detailed abstraction database to plan assessing current and future water resources availability in Scotland.

David Haro Monteagudo, Shaini Naha, and Miriam Glendell

Scotland’s land and water resources are increasingly vulnerable to periods of droughts, impacting water users and the water environment. Abstractions from sectors with high water demands are forecasted to exacerbate the direct impacts of climate change by amplifying both the frequency and the duration of drought events. Previous studies that have assessed the potential future water scarcity in Scotland were limited by the lack of available data on actual abstractions. These studies assumed that all abstraction licences were used at their maximum (i.e., were based on worst case scenario); and did not account for public water supply abstractions. Therefore, there is a need for accessible data on timely, open, and detailed abstraction return values for all sectors to overcome these limitations to allow a more accurate assessment of the current state of Scotland’s water resources and their vulnerability to climate extremes. We have collated a database that comprises of abstracted daily volumes from different locations within the water bodies, for various sectors from Scottish Environmental Protection Agency and abstracted daily volumes for public water supply aggregated at the catchment level from Scottish Water. We then use these daily abstraction time series available for the common time 2018-2022, in conjunction with available daily river flow historical and future projections, to determine the available volume of water, per catchment, per day. This enables extracting the drought events, and drought characteristics such as frequency, duration, and intensity of droughts. This research will inform future water resources management in Scotland by identifying which regions and sectors may be subject to increased water scarcity pressures in the future.

How to cite: Haro Monteagudo, D., Naha, S., and Glendell, M.: Using a detailed abstraction database to plan assessing current and future water resources availability in Scotland., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16678, https://doi.org/10.5194/egusphere-egu24-16678, 2024.

A.14

EGU24-482

ECS

Predicting Global Change impacts on streamflow dynamics using distributed hydrological modeling in a data-scarce nested tropical catchment in West Africa.

Albert Elikplim Agbenorhevi, Julian Klaus, Leonard Kofitse Amekudzi, Nelly Carine Kelome, Ernest Biney, and Ernestina Annan

Currently, the global water cycle is experiencing radical shifts and the associated global water crisis requires rapid action by stakeholders to mitigate adverse impacts on both human populations and ecosystems. This urgency in action is driven by the combined effect of Climate Change and Land-use land cover change (LULCC) and the associated challenges in securing clean water sources. The Global Change from climate change is making water scarcity worse in places that are water-stressed, causing more competition and even conflicts over water resources. Addressing the global water crisis is especially challenging in the data-scarce region of the Global South where the status of hydrological processes and water availability is poorly constrained. Here, progress in hydrological predictions through robust hydrological models remains on top of the research agenda. General for the Global South, and particularly for West Africa, is the limited hydrological process understanding of tropical catchments with accelerating land cover change. The focus of the research study seeks to address the following research questions:
• How does climate change alter hydrological processes in tropical catchments and does this alter streamflow regimes across nested catchments?
• How does and what are the contribution of LULCC in spatial-temporal changes of streamflow in a nested catchment in addition to the alterations driven by climate change within a given West African region?
To address the questions above, we will rely on data from the Pra River Basin in West Africa. In the present study, we employed Google Earth Engine (GEE) and Random Forest Classifier (RFC) to assess a time-series spatio-temporal land-use/cover change and change detection of the Pra River Basin for the period 2007 to 2023. Focusing on five (5) LULCC classifications has become crucial to the region's unregulated large and small-scale mining activities. The use of the Normalised Difference Water Index (NDWI), and Modified NDWI (MNDWI), was effective in extracting water surface areas for the change detection and pressure on the Pra River Basin and dealing with the overestimation phenomenon. We next integrate the processed LULCC into an eco-hydrological model that is validated against observed and reanalysed streamflow at different stations, soil moisture, and groundwater data. Future work will consist of estimating the impact analysis of Global Change on streamflow using an ecohydrological model that will be driven with the downscaled climate scenarios from CMIP6 and time-series land use change scenarios. This multifaceted approach is novel to the scientific understanding of water resource dynamics in the face of Global Change in tropical systems.

How to cite: Agbenorhevi, A. E., Klaus, J., Amekudzi, L. K., Kelome, N. C., Biney, E., and Annan, E.: Predicting Global Change impacts on streamflow dynamics using distributed hydrological modeling in a data-scarce nested tropical catchment in West Africa., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-482, https://doi.org/10.5194/egusphere-egu24-482, 2024.

A.15

EGU24-4454

ECS

Evaluating climate change impacts on the hydrology of Kamp catchment, Austria, under different shared social pathways (SSPs)

Zryab Babker, Tim G. Reichenau, Morteza Zagar, and Karl Schneider

Climate change can severely affect water fluxes at the land surface and thereby water availability as well as floods and droughts leading to increased risks for man-environment systems. Understanding the impacts of climate change on future water resources at a catchment scale is essential for strategic planning and efficient integrated water resources management. In the frame of the DISTENDER project (EU Horizon-ID 101056836), climate change impacts upon several catchments in Europe are analyzed. A key goal of DISTENDER is to develop robust strategies for climate change adaptation. For the simulation of climate change impacts on water resources, the Soil and Water Assessment Tool (SWAT+) was selected for its accessibility, robustness, and transferability. Here we address the issue of effects of different climate models vs. shared socioeconomic pathways (SSPs) by driving SWAT with results of three models (CanESM5, EC-EARTH3, MPI-ESM1-2-HR) run of the updated Coupled Model Intercomparison Project Phase 6 (CMIP6) with four SSPs (SSPs 1-2.6, 2-4.5, 3-7.0, 5-8.5), respectively. The Kamp River in Lower Austria was selected as an example catchment because it is the longest river in the “Waldviertel” region, which has significant ecological, societal, and economic importance. The SWAT+ model was calibrated and validated at different locations in the catchment. Future climate change projections for the period 2021 to 2050 were obtained from CMIP6 and were statistically downscaled. Annual 3-day high runoff was used as a proxy for the extreme high runoff characteristics. Trends and variations of the water balance components were compared.

All climate models show an increase in average annual precipitation ranging from 5 % (MPI-ESM1-2-HR) to 17 % (CanESM5). In all climate models and SSPs, the 3-day high runoff at Stiefern gauge (near the catchment outlet) for 10, 50, and 100-year return periods is projected to increase. CanESM5 and EC-EARTH3 show the highest (54 %) and the lowest (13 %) increase in the 3-day high runoff for 10, and 100-year return periods respectively, variations across the SSPs range from 12 % (SSP1-2.6) to 77 % (SSP 5-8.5) for 100-year return periods. Changes in the average annual evapotranspiration across the different models range from 12 % to 18 %, and variations across the SSPs range from 14 % to 16 %. For all models, the average annual soil moisture in the catchment decreases significantly (5 % to 18 %), across SSPs the decrease ranges from 9 % to 13 %.

Our results indicate that the effects of choosing different models to reflect the changes in the runoff and average annual water balance components exceed the effects of different SSPs. Thus, decision-makers and planners should select a model according to their planning goal (i.e. use a model with extreme change to reflect the maximum potential risk). This research is intended to develop adaptation and mitigation strategies to reduce risks and vulnerabilities and to contribute to effective management of water resources in the catchment within the framework of the DISTENDER project.

Keywords: Climate change, CIMP6 Climate Model, SWAT+ model, Kamp catchment, Austria

How to cite: Babker, Z., G. Reichenau, T., Zagar, M., and Schneider, K.: Evaluating climate change impacts on the hydrology of Kamp catchment, Austria, under different shared social pathways (SSPs), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-4454, https://doi.org/10.5194/egusphere-egu24-4454, 2024.

A.16

EGU24-11834

ECS

Climate change impact on the hydrological processes over an alpine basin: the Adige River

Martin Morlot, Alison L. Kay, and Giuseppe Formetta

Hydrological extremes (drought and floods) have undeniable financial implications and are predicted to grow in the next years. Yet to understand their future local impacts it is necessary to understand the evolution of the governing hydrological processes. Such is the case for the Adige basin, an important basin in Italy, where understanding changing patterns of hydrological processes is crucial to optimally plan competing water uses, such as hydroelectric production and agricultural water allocation.

Euro-CORDEX models provide future climate projections throughout the region, for different emissions scenarios (RCP 2.6, 4.5, 8.5) and climate models (13). Upon the application of a downscaling and bias correction methodology against observed climate variables (i.e. air temperature and precipitation), a process-based semi-distributed digital twin of the Adige River basin is implemented. Hydrological process variables (snow, actual evapotranspiration, soil moisture and discharge) are obtained for the entire basin and the timespans of the different Euro-CORDEX models (1980-2005 for the historical baselines, 2005-2100 for the projections) at daily temporal scale and 5 km² spatial resolution. The temporal and spatial patterns for discharges are evaluated through the average monthly values for 6 sub-catchments. Other process variables such as snow, actual-evapotranspiration (AET) and soil moisture (SM) are assessed against remote sensing datasets. The resulting climate and hydrological end of the century projections (2075-2100) are compared to historical baselines (1980-2005), to assess projected changes.

The digital-twin model is found to reproduce discharge patterns accurately, with an average KGE of 0.8, and provides a good fit for snow and AET, with average correlations of 0.95 and 0.96 respectively. A reasonable fit is found for SM, with an average correlation of 0.5. Careful assessment of the digital twin model through these variables ensures that it reproduces accurately historical local hydrological processes and increases confidence in the quantification of these variables under future projections.

The results of our study give regional policymakers insights into possible future scenarios and how these affect water resources and their potential impacts and adaptations on several economic sectors.

How to cite: Morlot, M., Kay, A. L., and Formetta, G.: Climate change impact on the hydrological processes over an alpine basin: the Adige River, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-11834, https://doi.org/10.5194/egusphere-egu24-11834, 2024.

A.17

EGU24-1478

Assessment of drought prone areas in Slovakia according to the changes in the long-term mean discharges

Katarina Jeneiova, Lotta Blaskovicova, Katarina Kotrikova, Zuzana Danacova, and Jana Poorova

The assessment of changes in the hydrological regime under the climate change uncertainty is especially important for the decision making processes as the hydrological design values, derived for a reference period, are directly used for decision making in many areas of water management, including drought management. Recent local studies confirmed that there are changes in hydrological regime of the last decades in comparison to the currently used reference period 1961-2000 in Slovakia. Therefore, the selection of the reference period for the design values is under revision. In the first step, long-term mean discharge observations from the state hydrological network with near natural regime were analysed. The newly proposed period 1991-2020 was compared to the reference period 1961-2000 and the deviations of long-term discharges in selected water-gauging stations were assessed. The newly proposed reference period was selected for the analysis, as it is recommended by the World Meteorological Organisation for the purpose of climate change monitoring and better comparability of climatological and hydrological characteristics. As the second step, maps of the drought prone areas were drawn according to the spatial distribution of the results. We hope that this analysis will serve as supporting material to help the decision makers in policy making process and toward more effective drought management in Slovakia.

How to cite: Jeneiova, K., Blaskovicova, L., Kotrikova, K., Danacova, Z., and Poorova, J.: Assessment of drought prone areas in Slovakia according to the changes in the long-term mean discharges, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-1478, https://doi.org/10.5194/egusphere-egu24-1478, 2024.

A.18

EGU24-8932

ECS

Model Calibration and discharge simulations during extreme drought events for the Rhine River Basin using WRF-Hydro.

MSc. Andrea Campoverde, PD. Dr.Uwe Ehret, Dr.Patrick Ludwig, and Prof. Dr. Joaquim Pinto

Recent drought events, leading to low water levels, have significantly affected navigation through the Rhine River and the transportation of goods. It has become imperative to analyze the conditions in which these events occurs to establish actions to prevent monetary losses. The main focus of this study is to test how well the hydrological model WRF-Hydro can capture extremely low water levels in the Rhine River basin. Using the meteorological reanalysis dataset ERA5 as forcing data for the model, we simulate the streamflow from January 2016 to December 2018, which includes the recent drought event in the Summer of 2018. Within the model, the calibration of various parameters allows the evaluation of the streamflow from WRF-Hydro to be contrasted with the daily observed values. The parameters influencing the amount of water routed across the basin are generally constant throughout the domain. Land use cover and terrain slope were used to create spatially distributed parameter values, avoiding the calibration process of testing a range of values and, therefore, reducing computational time. These promising results enables us to analyze recent and future drought events under different climate conditions.

How to cite: Campoverde, MSc. A., Ehret, PD. Dr. U., Ludwig, Dr. P., and Pinto, P. Dr. J.: Model Calibration and discharge simulations during extreme drought events for the Rhine River Basin using WRF-Hydro., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-8932, https://doi.org/10.5194/egusphere-egu24-8932, 2024.

A.19

EGU24-2873

ECS

Potential assessment of flood resource utilization based on the inflow flood identification model

Jing Huang, Chao Tan, Xiaohong Chen, and Jiqing Li

The potential assessment of flood resource utilization is a prerequisite for the rational allocation of water resources and storage capacity in a watershed. In response to the increasingly uneven distribution of water resources in the context of climate change, an inflow flood identification model was established based on the Kolmogorov-Smirnov test, improved peak-over threshold method, and time-varying parameters with Poisson distribution model. A potential assessment method of flood resources utilization in reservoir groups was proposed based on constraints such as the comprehensive regulation and storage capacity of the watershed and water demand. The four cascaded reservoirs in the lower Jinsha River (Jinxia Four Reservoirs), namely Wudongde, Baihetan, Xiangjiaba, and Xiluodu, was used as a case study. The results show that: 1998 and 2002 are the consistency change points of the runoff seies from June to November at Xiangjiaba Hydrological Station. The main type of inflow flood is short-fat, and the 3-day flood volume is a key indicator of balanced comprehensive utilization benefits except for the flood peak. Jinxia Four Reservoirs are constrained by storage capacity, when encountering floods with a design standard of once-in-a-century or below, the potential utilization of flood resources is 37.27×10⁸m³. It is recommended to continuously optimize the storage capacity by raising the water level to 952.26m, 806.77m, 576.31m, and 373.99m in sequence of Jinxia Four Reservoirs. This work aims to provide reference for the optimal allocation of water resources and storage capacity in the watershed.

How to cite: Huang, J., Tan, C., Chen, X., and Li, J.: Potential assessment of flood resource utilization based on the inflow flood identification model, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2873, https://doi.org/10.5194/egusphere-egu24-2873, 2024.

A.20

EGU24-10709

ECS

Environmental Impacts of Developing Flood Protection Systems throughout a Marshland Ecosystem in Lower Louisiana: a Numerical Case Study

Daniel Barreca

Louisiana is a state in the United States of America that is experiencing the multiple challenges of climate change, extreme weather events (such as hurricanes), and human intervention impacts for flood protection. The marshland regions of lower Louisiana have been heavily impacted by human influence, since the state was originally formed and maintained by deposition of sediment carried from the Mississippi River. Not only has impact of human intervention impacted the sediment transport processes, but there has also been significant human development of levee systems and other flood protection structures in Louisiana’s coastal environment. Specifically after Hurricane Katrina, additional levee systems, environmental control structures, and floodgates were built in this marshland region. A few different design criteria are important to analyze for these systems, some of the more notable design criteria are flood protection, navigational safety for ships passing through floodgates, marshland protection, water quality, and system biology. In addition to monitoring human impacts, the US Army also seeks to understand how the system behaves under long-term climate change impacts.

While flood protection is a primary motivator for building these systems, it is important to ensure that structures built do not have adverse effects on the local wildlife or commercial/recreational opportunities for the locals in these areas. Adaptive Hydraulics (AdH) is a finite element based 2D shallow water equation solver that can be used to numerically evaluate these impacts. Another focus of this study is to analyze the indirect impacts of structures built since 2004. To ensure that everything built since then has not had major impacts on the local wildlife or commercial/recreation opportunities, AdH and PTM can also be used to gain insight into that impact. The numerical modelling portion is the author’s direct contribution to the project, though the overall project of developing Lower Louisiana, and its impact of that and climate change on the natural environment and local people will be discussed.

How to cite: Barreca, D.: Environmental Impacts of Developing Flood Protection Systems throughout a Marshland Ecosystem in Lower Louisiana: a Numerical Case Study, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-10709, https://doi.org/10.5194/egusphere-egu24-10709, 2024.

A.21

EGU24-9237

ECS

A Graphical Representation of Climate Change Impacts with Associated Uncertainties

Jose George and Athira Pavizham

Recent decades have seen increased occurrence of extreme climatic events, which have had devastating consequences, both in terms of loss of life and property. Proper understanding of the possible variations in climatic extremes is important in developing mitigation and adaptation plans. Climate change impact prediction employs a series of numerical models, each with their own limitations that contribute towards the overall uncertainty. Climate change impact prediction results are often not intuitive to a decision maker and the added complexities from uncertainties can complicate the policy making exercise. A clear and concise representation of the possible risks of climate change and the associated uncertainties needs to be developed to bridge the gap between the climate scientist and the policy maker. Here, a framework for graphical representation of regional climate risks in terms of hazards and vulnerabilities is developed. The uncertainties are quantified in terms of level of confidence as the result of an ensemble exercise. To help regional stakeholders relate to the prediction results, analysis of extremes is performed with respect to historical hazards in the region. Risk factors for climate extremes that happened in the past in the region are studied and the future risk for an event of same return period is compared to the historical risk. The methodology is validated in the Bharathapuzha catchment in Kerala, India, a catchment which is identified to be climate change hotspot. In terms of flood events, the risk of low intensity flood events is seen to be increasing in the catchment with high confidence, while high intensity flood events are seen to be predicted at low levels of confidence. The catchment is seen to be drying up with high intensity drought events being predicted at high confidence.

How to cite: George, J. and Pavizham, A.: A Graphical Representation of Climate Change Impacts with Associated Uncertainties, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9237, https://doi.org/10.5194/egusphere-egu24-9237, 2024.