S24

Cold region runoff and groundwater change

Changes in the storage and delivery of water impact society. Cold regions are particularly susceptible to the effects of climate change so it is crucial to understand and plan for likely future hydrological changes in these regions. Changes in the timing and amount of meltwater release from snow and ice have implications for ecosystems and communities that depend on this water supply. Melting of permafrost can further lead to both ecosystem changes and infrastructure instabilities and damage. Due to the importance of this topic, ‘How will cold region runoff and groundwater change in a warmer climate?’ was selected as one of the key 23 unsolved problems in hydrology (UPH). This session will bring together experts in cold regions hydrology, climate change, biogeosciences, remote sensing, and groundwater research to address this UPH. We welcome submission of presentations on all aspects of modelling and long-term monitoring of cold region hydrological components, particularly on:
• projected changes to the hydrological cycle in the cryosphere;
• assessment and monitoring frameworks for permafrost;
• long-term observations of snow and glacier melt;
• factors influencing longer-term water routing mechanisms;
• changing societal water needs in cold regions;
• implications for water systems operation and risk management;
• cold region ecosystem dependencies.

Convener: Melody Sandells | Co-Conveners: Felipe de Barros, Fuqiang Tian, Gokcen Uysal, María José Polo
Orals
| Tue, 31 May, 13:30–15:00|Room Rondelet 2
Posters
| Attendance Tue, 31 May, 15:00–16:30|Poster area

Orals: Tue, 31 May | Room Rondelet 2

Chairperson: Melody Sandells
13:30–13:45
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IAHS2022-681
Pedro Torralbo, Rafael Pimentel, Javier Herrero, Cristina Aguilar, Fátima Moreno, and María José Polo

In Mediterranean high mountain environments, the snow accumulation/melting regime determines the surface water balance, redistributing the fractions of infiltration/runoff and evaporation from the ground and conditioning the volume circulating in the river channels. Therefore, the snow cover adds another degree of complexity to the precipitation-flow relationships in these systems (e.g., rain-on-snow events). Thus, a process-oriented approach is necessary when studying these relationships.

The definition of indicators derived from satellite remote information is a widespread technique in the characterization of the hydrological state of a basin. Previous studies in these areas have identified the state of vegetation, through its vigorousness using the NDVI (Normalized Difference Vegetation Index), as a good indicator for the characterization of soil water content at the beginning of the hydrological year (Gómez-Giráldez et al., 2014).

Therefore, in this context, the objective of this study is to analyze the relationships between changes in the state of watershed vegetation and flow variations in snow-influenced watersheds as additional information to anticipate downstream seasonal inputs using previous remote sensing information. For this purpose, a 20-year series of daily flow rates at a gauged point in the Guadalfeo river basin, one of the headwater catchments of the Sierra Nevada National and Natural Paro river was used, together with meteorological time series and the simulation of snowpack water flows using the physical-based model SNOWMED. Hence, two flow events are selected: i) rainfall-runoff events and ii) melt-runoff events. The vegetation dynamics in the basin is analyzed through variations of NDVI, derived from Landsat data (TM and ETM+) during the same study period.

From the analysis, the lags between the local change in NDVI, the loss of snow-covered area at the headwaters and the occurrence of melt or mixed flow events allow us to establish the onset of the generalized melt state in the basin, as well as to estimate threshold antecedent states. The results deepen the understanding of the hydrological dynamics in the basin, as well as the capacity of the NDVI as a tracer of the hydrographs associated with the generalized states of melting in Mediterranean mountain basins.

How to cite: Torralbo, P., Pimentel, R., Herrero, J., Aguilar, C., Moreno, F., and Polo, M. J.: Using NDVI as an indicator of snowmelt runoff in Mediterranean mountain catchments: application to the Guadalfeo river basin, Sierra Nevada., IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-681, 2022.

13:45–14:00
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IAHS2022-99
Nataliia Nesterova, Olga Makarieva, Andrey Shikhov, Andrey Ostashov, Anastasiya Zemlyanskova, and Vladimir Alexeev

Aufeis are widespread in the territory of the North-East of Eurasia (including the basins of large rivers in permafrost, such as the Yana, Indigirka, Kolyma, Anadyr, Penzhina Rivers and rivers of the Chukchi Peninsula. They comprise an important water resource of the study region. Based on the analysis of Landsat satellite images for the period 2013-2019 the number and characteristics giant aufeis (area ≥0.1 km2) were estimated. As Landsat images do not always allow correctly assess the maximum area of aufeis, it was adjusted to get the maximum value before the beginning of ablation period for the assessment of aufeis resources.

After correction total maximum area of aufeis formed by groundwater reaches 4529 km2. The aufeis resources of the North-East and of the large river basins were assessed. The aufeis resources vary from 0.4 to 4.25 km3 (or 3.7 – 11 mm) for individual basins of large rivers. They are at least 10.6 km3 in total or 5 mm of water depth in average for the study area.

The contribution of aufeis runoff to streamflow in different seasons was calculated for 58 hydrological gauges (area 523 – 526000 km2). Aufeis annual runoff varies from 0.3 to 29 mm (0.1 – 22%, average 3.8%) with the share in winter runoff amount about 6 – 712 % (average 112%) and the spring freshet 0.2 – 43% (average 7.1%).

The influence of aufeis and glaciers on the water balance is compared – in general, the aufeis runoff exceeds the glacial runoff. The response of aufeis to climate change depends on different factors of the natural system.

The dynamics of aufeis formation is directly related to winter runoff, which changes are observed in different parts of the cryolithozone. The presented results are relevant for studying the impact of climate change on the hydrological cycle and its components in the permafrost regions of the Northern Hemisphere.

The study was carried out with the support of RFBR (19-55-80028, 20-05-00666) and St. Petersburg State University (project 75295879).

How to cite: Nesterova, N., Makarieva, O., Shikhov, A., Ostashov, A., Zemlyanskova, A., and Alexeev, V.: Aufeis resources and their role in water balance of North-Eastern Eurasia, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-99, 2022.

14:00–14:15
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IAHS2022-604
Nikita Tananaev, Vladislav Isaev, and Dmitry Sergeev

Hillslope water tracks are landmark features of permafrost landscapes, yet their origin and future evolution are debated. Water track networks are believed to be fully developed fluvial networks constrained by permafrost. Hence one potential evolution scenario under future climate is rapid thermo-erosional development of water tracks. Permafrost tundra environment near Vorkuta, European Russian Arctic, N67°17’, E63°39’, is a model ecosystem for this scenario, developing under changing climate and permafrost degradation.

Figure 1 Hydrographical network of the study region, 30 km south of Vorkuta, European Arctic Russia

Field works at the study site were carried out in September 2017 and repeated in 2021. Local streams and groundwater, from both boreholes and soil pits, were sampled for dissolved organic carbon (DOC) and nitrogen (DON), major ions, stable water isotopes and trace elements. Electrical resistivity tomography (ERT) was used to study permafrost distribution.

First-order water tracks are minor linear depressions, occupied by Betula nana and rarely expressed in local topography, hosting fast subsurface runoff. Initial stages of permafrost perturbation, these forms are major pathways of DOC export from permafrost slopes, with mean DOC content is 29 ± 2 mg/L. Channelized runoff appears farther downslope, at the slope bend. Increased input from supra-permafrost groundwater is traced by Ca2+ increase, and rapid decline in DON content, from 0.1-0.3 mg/L to zero. At toeslopes adjacent to the Vorkuta R., larger streams coexist with polygonal depressions dissecting otherwise flat riverine terrace. In streams, the DOC content decreases to 12 ± 1.5 mg/L, while in depressions, it raises to 38-39 mg/L. Terrain perturbation by water tracks provides initial slope drainage and promotes fast DOC export from slope soils and its potential microbial consumption.

Permafrost is discontinuous, and open taliks are present under water tracks and polygonal depressions, as shown by ERT survey. Taliks allow upward groundwater movement and drainage to the fluvial network. Sub-permafrost groundwaters were sampled from two boreholes, draining two major regional aquifers, and their traces were found in both large streams and minor water bodies of the region.

How to cite: Tananaev, N., Isaev, V., and Sergeev, D.: Hydrological surface-subsurface connectivity in permafrost tundra environment, European Russian Arctic, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-604, 2022.

14:15–14:30
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IAHS2022-454
Lucas Menzel and Li Han

Inspired by own field studies on permafrost and hydrological variability, a study was launched to investigate changes in runoff in southern Siberian catchments on the large scale. Until now, the reasons for the sometimes-drastic changes in river discharge remained more or less unanswered or were speculative. We combined data assimilation techniques, statistical analysis and hydrological simulation to investigate in detail the different climatic and physiographic impacts on the runoff behaviour of the Selenga (northern Mongolia / southern Siberia), the upper Lena and the Aldan (tributary to the Lena). Through this selection, we have included two different climatic and vegetation zones (semi-arid, transition zone between steppe and boreal forest, and humid, with exclusively boreal forest) as well as three areas with different permafrost extension (sporadic, discontinuous, continuous) in our investigations. We have selected a period of maximum data availability covering the years 1954-2013.

First, we were able to establish that due to the oscillating, large-scale atmospheric circulation over Siberia, precipitation and runoff are subject to periodic natural changes between rather dry and wet conditions. In addition to these oscillations, precipitation in all catchments shows negligible long-term trends over the 60 years period. Thus, we associate the long-term trends in runoff with the impacts of permafrost degradation. In the predominantly semi-arid Selenga catchment, lateral permafrost degradation prevails, i.e. decreasing permafrost extent. We found that there is a strong loss of water due to increased infiltration and seepage, resulting in drier conditions and ultimately lower runoff. In the boreal Lena and Aldan catchments, on the other hand, vertical permafrost degradation is prevalent. However, a frozen and thus impermeable layer remains below the growing active layer, which leads to overall wetter conditions and increased runoff. This contrasting behaviour mirrors the "dry becomes drier, wet becomes wetter" phenomenon described in earlier research. We also found that the warming-induced increases in permafrost thaw have led to major changes in the hydrological regimes of the three investigated basins. This integrated approach enabled new insights into the complex and highly dynamic hydrological changes that will provide impetus for subsequent studies. 

How to cite: Menzel, L. and Han, L.: Impact of changing climatic conditions and permafrost degradation on discharge in southern Siberian catchments, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-454, 2022.

14:30–14:45
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IAHS2022-542
Assessing the impact of climate change on seasonal runoff in the immediate future of snowy mountainous basins in Japan
(withdrawn)
Kazumasa Fujimura, Yoshihiko Iseri, Aki Yanagawa, and Shinjiro Kanae
14:45–15:00
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IAHS2022-367
Gokcen Uysal, Yusuf Ogulcan Dogan, Huseyin Soykan Civelek, Ali Arda Sorman, and Aynur Sensoy

Climate change drastically threatens water supply systems and ecosystems especially in water towers that maintain water demands downstream. Analyzing future implications in the timing and amount of snowmelt runoff is a crucial mission to develop required adaptation strategies against climate change effects. This study aims to estimate future snowmelt runoff and snow extent in terms of various metrics i.e. timing and the quantity for the Upper Euphrates Basin (41,109 km2). As the most upstream basin of the water tower Mesopotamia, the basin is located in the Eastern mountainous part of Turkey. The future characterization of snowmelt runoff and snow cover area is investigated taking the regional climate model projections into account through hydrological model applications. Furthermore, changes in snow line elevation and lag time in the snowmelt processes are examined. The basin is divided into two major sub-basins as Karasu Basin and Murat Basin. The conceptual hydrological models, HBV and HEC-HMS, have been utilized to establish a rainfall-runoff relationship. The models are calibrated and validated with observed daily total precipitation and average temperature data for the 1980-2010 period. Future projections are employed for 2025-2100 periods using EU-CORDEX data with various global circulation models.  CNRM-CM5 and HadGEM2-ES data sets and RCP 4.5 and RCP 8.5 emission scenarios are used for future projections. Climate data sets are subjected to local bias corrections. The preliminary results indicate decreases in snow cover extent, snow duration, and snowmelt runoff. The overall assessment will help us to understand how these changes will affect operations of water resources systems (downstream reservoirs) in terms of flood control, energy production, irrigation, and water supply, etc.

How to cite: Uysal, G., Dogan, Y. O., Civelek, H. S., Sorman, A. A., and Sensoy, A.: Analyzing the Effects of Climate Change for the Water Tower of Mesopotamia, Turkey, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-367, 2022.

Posters: Tue, 31 May, 15:00–16:30 | Poster area

Chairperson: Melody Sandells
P22
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IAHS2022-678
Dagmar Brombierstäudl, Susanne Schmidt, and Marcus Nüsser

Meltwater from the cryosphere is vital for water supply and livelihood security of the local population in the Trans-Himalaya. Due to decreasing glaciers and the increasing variability of seasonal snow cover, periods of water scarcity regularly occur in summer and spring. The widely neglected cryosphere component of aufeis, a seasonal ice body created by successive freezing of flowing water onto the already frozen surface is mainly located along rivers and streams. It stores base flow in winter and supplements river discharge during spring and early summer. Although this particular cryosphere component has been described for sub-polar permafrost regions across the northern hemisphere, only few studies have investigated Trans-Himalayan aufeis formation. Despite its possible importance for local hydrological systems, a better understanding of specific spatio-temporal freezing and melting patterns is lacking. In the study area 27 aufeis fields, which frequently reappear each year in the same places, with an average maximum extent of 9.2 km² in May were mapped, located at a mean elevation of 4700 m a.s.l. Size of individual aufeis fieldsranges from 0.007 km² to 1.7 km². Based on the 13-year monthly average, an accumulation and depletion phase can be differentiated, which are negatively correlated with surface temperature derived from MODIS data. The accumulation period lasts from November until April, with a peak of monthly average area in January and February. Melting starts in May and aufeis fields disappear by the end of July. A slightly increasing trend in the average ice covered area during the freezing period was found, whereas the maximum extent in May is consistent throughout the time-series with only a minor, non-significant downward trend. In addition, correlation analysis between monthly average overflow area and temperature suggests that temperature is an important variable regarding overflow activity. Temperatures above the 13-year average result in larger overflow areas compared to years with lower temperatures, especially during January, February and March whereas lower temperatures are more beneficial for ice formation in November.

How to cite: Brombierstäudl, D., Schmidt, S., and Nüsser, M.: Spatial distribution and seasonal occurrence of Aufeis in the Trans-Himalayan Tso Moriri basin, eastern Ladakh, India, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-678, 2022.

P23
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IAHS2022-328
Andrea L. Popp, Nicolas Valiente, Sigrid Trier Kjær, Anja Sundal, Kristoffer Aalstad, Alexander Eiler, and Peter Dörsch

Global warming in the Arctic is occurring at an amplified rate, resulting in enhanced permafrost thaw (e.g., Meredith et al., 2019). As permafrost thaws, layers of year-round unfrozen ground, so-called taliks, are created (Figure 1). Taliks represent new subsurface pathways that involve unknown consequences for fluxes of water, energy and solutes (e.g., Walvoord & Kurylyk, 2016).  With this study, we aim to contribute to an improved understanding of the current status of Arctic hydrology and biogeochemistry using a combination of modelling as well as satellite- and field-derived data from the Bayelva catchment in Ny-Ålesund, Svalbard. In summer 2021, we sampled various water sources (e.g., streams, lakes, snow, glacial meltwater, groundwater) to obtain a spatially resolved data set of tracers (e.g., major ions, radon, stable water isotopes, trace elements) and greenhouse gases (GHGs; CO2, CH4, N2O). Consequently, we delineate source water contributions to streams and lakes using conservative tracers combined with a mixing model (Popp et al., 2019). With the help of radon, we assess hyporheic exchange flow and short residence times (Popp et al., 2021). Lastly, to identify drivers and controls of GHG evasion, we link source water contributions and GHG concentrations. This work captures the current state of an Arctic catchment experiencing rapid changes and can therefore help to predict future effects of permafrost thaw and its impact on water cycle changes and GHG evasion.