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FS 3.230

Global change impacts for mountain water resources and downstream implications

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Details

  • Full Title

    FS 3.230: Global change in high mountain environments: impacts on upstream water resources and downstream implications
  • Scheduled

    TBA
  • Location

    TBA
  • Convener

  • Co-Conveners

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  • Assigned to Synthesis Workshop

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  • Thematic Focus

    Cryo- & Hydrosphere, Monitoring, Multi-scale Modeling, Water Cycle, Water Resources
  • Keywords

    hydrology water resources, modelling and monitoring, upstream and downstream

Description

Global climate & socioeconomic change affects high mountain hydrology and water resources across the globe with significant downstream implications. Hydrological and water resources research in high mountains has to deal with strong variations across spatial and temporal scales which requires specific understanding and varying approaches. This session welcomes contributions that showcase novel methods and findings on how climate change and human activity alter the high mountain water cycle, and what implications these alterations have on different sectors in downstream regions. We in particular welcome contributions:

  • focusing on novel techniques to improve observations or modelling related to mountain hydrology as well as its linkage to downstream regions and sectoral impacts
  • ranging in spatial scales from single catchments, which can be in any mountain region of the world, up to the global scale – addressing historical, present, or future periods, or a combination
  • considering the physical and/or the socioeconomic side of mountain water resources
  • focusing on streamflow or other water balance components

Submitted Abstracts

ID: 3.9794

Hydroclimatic role of the Alps as a source of precipitation on European agricultural land

Nike Chiesa Turiano
Tuninetti, Marta; Laio, Francesco; Ridolfi, Luca

Abstract/Description

The Alps are vital in generating both perennial and seasonal runoff through snow and ice melting, providing a fundamental water supply to downstream ecosystems and human activities, particularly agriculture. However, the relevance of mountains as water reservoirs for lowlands stands also in their role as evapotranspiration sources. Evapotranspiration (ET) plays a major role in the water balance of alpine catchments as it pumps back to the atmosphere 60-80% of the precipitation and regulates precipitation recycling. The recycling and downstream effects of changes in ET are not only hydrological but extend to economic and socio-political dimensions. Understanding these interactions is vital to addressing challenges in water resource management and agriculture sustainability. While the dependency of lowland agricultural production on surface and groundwater deriving from snow and glacier cover over the Alps has been widely studied, research on the atmospheric link between the Alps and European agricultural land remains limited. This study addresses this gap by examining the geographical destination of evapotranspired water from the Alps and identifying quantitative water vapor links between alpine and agricultural regions with particular attention to crop-growing seasons and precipitation patterns. To effectively evaluate the fate of evapotranspired water, we employed the yearly reconciled outputs of the water vapor tracking model UTrack over the 2008-2017 mean year. Due to the spatial variability and the critical role of local factors in shaping ET within the alpine environment, we coupled UTrack with the high-resolution ERA5-Land dataset. This approach provides insights into the relationship between alpine water cycles and downstream hydrological dependencies.

ID: 3.11234

Integrating hydrological, sediment dynamics and geomorphic assessments for sustainable floodplain management in the Camarones River Basin (Colombia)

Giacomo Pellegrini
Nardini, Andrea Gianni Cristoforo; Mao, Luca

Abstract/Description

Mountainous regions are major sediment suppliers, shaping river’s downstream geomorphic and hydrological processes. Sediment supply and geomorphic processes are particularly active in tropical environments owing to intense seasonal precipitations. These processes affect fluvial ecosystems status and increase flood risks, especially when the basins are affected by deforestation and in-channel sediment mining. In tropical regions, data scarcity complicates sediment dynamics assessment, while anthropogenic pressures affect downstream hydro-sedimentological processes and ecosystem services. This study develops in the Camarones river, which drains a 598 km² basin in northern Colombia, including parts of the steep Sierra Nevada Range, and discharges into the Camarones lagoon, a nationally protected area on the Caribbean Sea. The study aims at integrating catchment-scale hydrological and sediment budget modelling with reach-scale fluvial geomorphological assessment and field measurements of sediment transport dynamics. Hydrological modelling is conducted using HEC-GeoHMS, sediment budget estimations are performed with CASCADE, while in situ measurements of sediment transport, hydraulic variables are carried out with a mix of techniques (drone surveys, Bunte traps, Arduino and water level pressure sensors, manual Wolman surveys) within a simplified approach inspired to the River Styles Framework®. Preliminary findings highlight the potential of this integrated approach to analyze and understand sediment dynamics across multiple scales and under projections of climate change, with the aim of providing sustainable floodplain management guidelines. This research is a key component of a larger initiative funded by GCBC (UK), which explores socio-ecological perspectives on sustainable floodplain management and climate change impacts on river ecosystems and biodiversity (NATIVE project).

ID: 3.11457

The paradox of choice: Evaluating climate change projections for hydrological impact models considering uncertainty and spatiotemporal aspects.

Santiago Núñez-Mejia
Crespo, Patricio; Willems, Patrick; Ochoa-Sánchez, Ana

Abstract/Description

Many climate change projections are available or under development on a global, regional, and local scale. This diversity can be explained by the increases in computational power and the rising pressure as we experience the hydrological impacts of climate change worldwide. While many studies propose methodologies to evaluate General Circulation Models (GCMs) or to intercompare downscaling methods, there is a knowledge gap for hydrological impact modellers when they need to choose between using available projections or developing new ones to use as input in water resources models. To this end, we propose a methodology to evaluate the spatial and temporal aspects of precipitation and temperature projections used for hydrological modelling. Due to the broad range of temporal scales of interest, it evaluates sub-daily to yearly projections. This methodology is applied in a high mountain tropical catchment with complex orography as case study. We focus on high mountains because they are considered uncertainty hotspots due to the high spatial variability, sparse observations and reduced performance of common techniques. Our method is guided by the cascade of uncertainty concept which represents the uncertainty introduced in each step of the impact modelling chain. In the first step of the method, each projection is treated as a streamline of the cascade because it uses a limited number of scenarios, GCMs, downscaling methods and reference observational products. In a next step, precipitation and temperature indicators at hydrologically relevant scales are quantified during the historical period to evaluate the representation of the present climate in the catchment of interest. Finally, indicators during the future scenario are included to identify the signal of climate change and to detect the projected changes in the water cycle and the possible implications for water resources over a catchment prior to the development of a hydrological model. Although the selection of the best projection is neither feasible nor foreseen, this methodology aims to guide a coherent selection of available products or to identify the need to develop new ones for specific hydroclimate aspects before we continue adding layers to the already big cascade of uncertainty.

ID: 3.11656

Will rock glaciers buffer alpine streams against climate change?

Scott Hotaling
McGrath, Dan; Khatiwada, Ashlesha; Gianniny, Gordon; Pomeranz, Justin; Caskey, Simeon; Finn, Debra; Tronstad, Lusha

Abstract/Description

Climate change is dramatically impacting mountain ecosystems around the world. Perhaps the most visceral of these impacts is the ongoing recession of glaciers and perennial snowfields. However, surface glaciers and snowfields are not the only perennial ice features in mountain landscapes. Many forms of subsurface ice (e.g., rock glaciers) are also present and play an important, albeit understudied, role in water availability and aquatic ecosystem integrity in mountain systems. Theory predicts that surface ice features that are exposed to ambient conditions will recede faster than subsurface ice that is insulated by debris cover. A limited amount of evidence supports this expectation. Since 2015, we have been monitoring high-alpine streams in the Teton Range, USA fed by three different sources—surface glaciers, rock glaciers, and seasonal snowpack—to understand the fate of aquatic ecosystems amidst climate change and how different sources may yield differing rates of change. In 2014 and 2022, LiDAR data was also generated for the Teton Range. By pairing our 10+ years of aquatic monitoring data with physical change inferred from LiDAR, we were able to gain rare insight into the links between physical change to ice sources and downstream ecosystems. Specifically, we found that rock glaciers in the Teton Range have been resistant to climate-induced ice loss while surface ice features have seen dramatic declines. However, these physical changes have not been mirrored in nearby streams. For instance, streams fed by seasonal snowpack and small perennial ice features have warmed rapidly during the summer while streams fed by surface glaciers and rock glaciers have remained largely unchanged.

ID: 3.12215

Investigating the drivers of past and future change in the cryosphere and downstream water resources in a tropical Andean basin

Catriona Fyffe
Potter, Emily; Shaw, Thomas E.; Miles, Evan; McCarthy, Mike; Castro, Joshua; Loarte, Edwin; Medina, Katy; Pellicciotti, Francesca

Abstract/Description

The Peruvian Andes contain glaciers which have undergone considerable mass loss over the past three decades and which face significant changes under future warming. Meltwater from snow and glaciers is important for water resources in this region, particularly in the dry season, and changes in the cryosphere could impact runoff regimes, downstream ecosystems and water users. To determine the drivers of past changes in the mountain water cycle, and investigate its likely future response under climate change, we run the fully distributed, hourly glacier-hydrological model TOPKAPI-ETH over the upper Rio Santa catchment in the Cordillera Blanca. We run the model from 1987 to present and then to 2100 in the future, forced in the past by bias-corrected WRF simulations, which are also used for statistical downscaling of 12 CMIP5 model projections which form a future climate ensemble. The ability of the model to replicate past glacier changes is assessed through comparison against historical glacier outlines, and we also evaluate model outputs against glacier mass balance, snow cover and gauged runoff datasets.

We find that past ENSO fluctuations have a significant impact on both glacier mass balance and the hydrological functioning of the catchment. Warmer El Niño air temperatures result in more negative glacier mass balances, but particularly negative mass balances are also found in low precipitation years which are not related to ENSO. Ice melt and on-glacier snowmelt is increased in El Niño years, resulting in an increase in discharge in highly glaciated sub-catchments. However, off-glacier snowmelt is decreased and discharges further downstream do not change significantly due to water loss from increased evapotranspiration. Despite the majority of the glaciers in the catchment facing overall negative cumulative mass balances over the past 30 years, there are exceptions, with positive balances found for the highest elevation glaciers. We also investigate the long term changes in the catchment runoff regime, demonstrating that the timing of ‘peak water’ in the dry season varies per sub-catchment depending on the degree of glacier recession. Our model outputs also allow us to explore the future changing resilience of the water cycle to predicted climate extremes.

ID: 3.12698

A coupled cryosphere-hydrology-crop model for the integrated assessment of water and food security in the Third Pole region

Manoj Khaniya
Mertzanis, Nikos; Gulpen, Marijn; Smolenaars, Wouter; Khanal, Sonu; Lutz, Arthur; Immerzeel, Walter; Biemans, Hester

Abstract/Description

The High Mountains of Asia, i.e., the Third Pole, are among the most important water reserves in the world because of the downstream dependency, for both direct human consumption and food production, on the upstream glaciers and snow. With changing climate and subsequent alteration of snow and glacier dynamics, the region has already been identified as one of the most vulnerable, necessitating detailed understanding of the impacts of these changes. Moreover, the trajectory of socio-economic development will also play a crucial role in the interplay between future water availability, demand, and food production. As such, with the aim of quantifying the consequences of both climate change and socio-economic development in the Third Pole region at a high spatial and temporal resolution, here we couple the widely used Spatial Processes in HYdrology (SPHY) model with the Lund-Potsdam-Jena managed Land (LPJmL) model. The idea behind this one-way coupling is to improve upon the poorly represented cryosphere processes in the latter by using the SPHY model outputs from the upstream mountain sub-basins while concurrently simulating the downstream hydrology, irrigation and crop growth with LPJmL. The coupled model further incorporates spatially explicit representation of multi-cropping, along with the extensive irrigation and inter-basin transfer canals for a realistic modeling of local agriculture and irrigation. As a first application result, an initial assessment of the importance of meltwater in different parts of the region and the contribution of mountain water to irrigated agriculture is presented. An overview of the current spatio-temporal status of water availability, demand and use, along with the crop-specific water requirement and yield is also provided. Future applications of the model are expected to increase our understanding of the diverse upstream-downstream relationships over the Third Pole region and help support adaptation design through the identification of vulnerability hotspots in different basins.

ID: 3.13116

A Digital Twin for Austria for Alpine Hydrology and Future Hazards

Mariette Vreugdenhil
Nagler, Thomas; Parajka, Juraj; Schwaizer, Gabriele; Hasliner, Beat; Massart, Samuel; Villegas, Carina; Reimer, Christoph; Tanhapour, Mitra; Sleziak, Patrik

Abstract/Description

Climate change is altering the Austrian Alps, including changing snow- and rainfall, which affects river discharge and has implications for water supply, hydropower, agriculture, tourism, and industry. The heterogeneity of mountains asks for high resolution methods to monitor and accurately predict changes in the water cycle in the Alps. In addition, recent studies have shown improvements in hydrological modelling of river discharge by adding soil moisture and snow cover data on top of precipitation and temperature to constrain the model. Both monitoring of water cycle components and hydrological modelling require reliable data at high resolution easily available to users with quality indicators. Recently, the European Centre for Medium-Range Weather Forecasts (ECMWF) has created the Climate Change Adaptation Digital Twin (ClimateDT), which will provide past, present, and future predictions on land surface variables at 5 km spatial resolution from 1990 to 2050 with different scenarios. Furthermore, the Copernicus Sentinel satellites provide high resolution observations providing information of the current state of the land surface, including soil moisture and snow from Sentinel-1 and Sentinel-3, respectively. Remote sensing of snow cover extent and soil moisture in mountainous areas is challenging due to shadowing effects and the many processes occurring simultaneously depending on location and height. We will present the first steps in creating a Digital Twin for Austria to monitor the water cycle in the Alps with first results of the ClimateDT products and Sentinel-based snow cover extent and soil moisture. ClimateDT soil moisture and snow depth are evaluated with the Sentinel based products. Furthermore, temperature, precipitation and soil moisture are validated with in situ observations from meteorological stations. The accuracy assessment will provide insights in the quality of the ClimateDT model for monitoring the water cycle. The work is carried out within the FFG funded Digital Twin Austria Alpine Hydrology and Future Hazards project with the goal to use the ClimateDT, along with Copernicus satellite-based data of snow extent and soil moisture, for hydrologic modelling of river discharge and to assess current and future water-related risks in the Austrian Alps.

ID: 3.13556

Assessment of Climate Change Impacts on Run-of-River Hydropower Production in Madi River Basin, Nepal

Shiksha Bastola

Abstract/Description

Hydropower remains the dominant renewable energy source globally, yet its production, particularly in Run-of-River (RoR) projects, is highly sensitive to climate change (CC) due to its dependence on streamflow availability. This study assesses the impacts of CC on hydropower generation, identifying both risks and opportunities. A comprehensive framework integrating high-resolution climate data development, hydrological modeling, and hydropower assessment is utilized to evaluate future hydropower production under changing climatic conditions.
Daily gridded observational data (0.05° × 0.05° resolution) from 1981 to 2010 were developed and used to downscale and bias-correct 18 Global Climate Models (GCMs) from CMIP6 for both historical (1981–2010) and future (2015–2100) periods. The Soil and Water Assessment Tool (SWAT) hydrological model is employed to simulate future streamflow, which is then used to estimate hydropower production at two operational and two planned RoR projects in the Madi River Basin, Nepal. Two future time periods—Near Future (NF: 2025–2054) and Far Future (FF: 2055–2084)—are analyzed under two Shared Socioeconomic Pathways (SSP245 and SSP585).
Results indicate that under the baseline design discharge, winter months show a significant increase in flow, while total annual production exhibits only a slight rise. However, when revised design discharge based on future climate projections is considered, monsoon-season hydropower production is projected to increase substantially compared to the baseline, with a similar trend in non-monsoon months. These findings suggest that hydropower developers must reassess design specifications to optimize power generation and revenue.
The study highlights the necessity of integrating climate resilience into hydropower planning and operations. Findings on production variability provide valuable insights for policymakers and stakeholders to enhance climate adaptation strategies. Additionally, the proposed methodology is adaptable for data-scarce regions, facilitating climate impact assessments and supporting sustainable hydropower development in developing nations.