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Gully erosion has been recognized as an important environmental threat in the Moldavian Plateau of Eastern Romania. The main objective of this study was to better understand gully development by providing quantitative information from long-term field measurements in small catchments over a 60 year period (1961-2020). Several methods were used to accurately measure and estimate gully growth.

Intense gully erosion has sculptured remarkable landforms around the town of Barlad. The permanent gully systems consist of two main gully types, discontinuous and large continuous gullies in valley bottoms. The discontinuous gullies are associated with small catchments (usually <100 ha in area) and ephemeral peak runoff discharges are usually ≤2 m³ s^-1.

Fourteen representative continuous gullies were selected, most of them having catchment areas <500 ha. Linear gully head retreat and areal gully growth rates were quantified for six decades. The results obtained indicate that gully erosion rates have decreased since 1960s (i.e. 19.5 m yr^-1 linear gully head retreat) to 3.2 m yr^-1 during last decade.

Gully growth is believed to be mainly triggered by severe rainstorms and resultant runoff events. However, the impact of late winter (especially thawing and snowmelt runoff) on gully development is often overlooked.  Mean annual air temperature at Barlad (Romania) is 10.2^oC and means annual precipitation is 508 mm (1961-2020), of which 35% falls during the cold season (October-March). Multiple annual field measurements on the growth of six continuous gullies between 1981-2000 indicate that half of the mean gully growth occurred in the cold season (in late winter, mainly in March).Based on data collected from different locations in the temperate zone of the Northern Hemisphere, it is possible to postulate that the relative contribution of the cold season to the gully development is highly variable and is closely related to climatic conditions. Thus, the contribution is very small in north-east China, ~25% in western Iowa (USA), ~50% in the Barlad Plateau (eastern Romania) and ~67% in the Middle Volga region (Russian Federation).

How to cite: Niacsu, L., Ionita, I., and Poesen, J.: Impact of changing climate on thawing and snowmelt-driven gully erosion in Eastern Romania, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-62, https://doi.org/10.5194/iahs2022-62, 2022.

We introduce the result of field observation associated with debris-covered snow-covered gorge in the Japanese Alps incorporating the effects of high mountain climate and extreme environment. The Japanese Alps strata that form the slopes and piedmonts of the extreme mountainous environments are highly erodible, which determines the specific features on the shrinkage of snow-covered gorges. In this study, we report the characteristics of debris-covered snowy gorges during the beginning of the snowmelt period in the extreme mountainous environment region of the Japanese Alps. We measured the temperature profiles and daily variations in typical nutrient parameters at debris-covered gorge and bare-ice glacier in the Kekachi valley in the northern Japan Alps of north-central region in Japan, to assess the characteristics association with the effect of debris-covered snowy gorge. The Kekachi valley is a typical snowy gorge region in Japan and also in the world that is located on the northern Japan Alps and lies over the Holocene sediment of the median tectonic line on Honshu Island, Japan. The debris covered snowy gorge remains almost throughout the year. This study indicated that the effect of debris coverage on the shrinkage of snow-covered gorges results in how the gorges respond to high mountain climate and environment of the Japanese Alps. We also compared debris-covered snowy area and bare ice area. Our results indicated that the highest ground surface temperature within 10 cm varied from 8 °C to 15 °C, having diurnal cycle for the crucial baseline factor associated with the existence of debris-covered snow-covered gores. Although, the growing meltwater discharge and surface lowering indicates that such snowy gorges are currently shrinking, their fronts remain remarkably stable, as also been observed in other regions.

How to cite: Mouri, G. and Chalov, S.: Characteristics of debris-covered snow-covered gorge during the snowmelt period in the Northern Japan Alps, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-619, https://doi.org/10.5194/iahs2022-619, 2022.

Persistent organic pollutants (POPs), such as organochlorine pesticides or polychlorinated biphenyls, are continuously delivered into the Arctic terrestrial environment, i.a. through snowfall (e.g., Cabrerizo et al., 2019; Hermanson et al., 2020). This happens despite the bans and restrictions on the use of these bioaccumulative substances (Stockholm Convention, 2008) and may lead to a secondary accumulation of contaminants in some glaciers in the Arctic continuing in the future (Pawlak et al., 2021). Upon melt, POPs are released with particulate matter and delivered to downstream ecosystems. However, the current deposition fluxes of POPs on glaciers are only sparsely recognized, which leads to uncertainties in these contaminants' snowmelt fluxes. In this study, we present a combination of spatially distributed sampling of fresh snowfall with total snow cover profiles upon Hans glacier (Svalbard, Norwegian Arctic) and the existing data on the snow cover (courtesy Institute of Geophysics, Polish Academy of Sciences) to estimate such fluxes for a seasonal snow cover of a tidewater glacier. Uncertainties related to the snow cover water equivalent estimations and the spatial variation in POPs concentrations are estimated and presented as obstacles to robustness of such studies. As a result, we provide data for future field measurement design which would decrease uncertainties in such estimations.

References:

Cabrerizo, A., Muir, D.C.G., Teixeira, C., Lamoureux, S.F., Lafreniere, M.J., 2019. Snow Deposition and Melting as Drivers of Polychlorinated Biphenyls and Organochlorine Pesticides in Arctic Rivers, Lakes, and Ocean. Environ. Sci. Technol. 53, 14377–14386. https://doi.org/10.1021/acs.est.9b05150

Hermanson, M.H., Isaksson, E., Hann, R., Teixeira, C., Muir, D.C.G., 2020. Atmospheric Deposition of Organochlorine Pesticides and Industrial Compounds to Seasonal Surface Snow at Four Glacier Sites on Svalbard, 2013–2014. Environ. Sci. Technol. 54, 9265–9273. https://doi.org/10.1021/acs.est.0c01537

Pawlak, F., Koziol, K., Polkowska, Z., 2021. Chemical hazard in glacial melt? The glacial system as a secondary source of POPs (in the Northern Hemisphere). A systematic review. Sci. Total Environ. 778, 145244. https://doi.org/10.1016/j.scitotenv.2021.145244

Stockholm Convention, 2008. Status of ratifications of the Stockholm Convention [WWW Document]. Secr. Stock. Conv. Clear. House. https://doi.org/10.1016/j.electacta.2005.05.025

Acknowledgement
This research was funded by a National Science Centre of Poland grant no. NCN 2017/26/D/ST10/00630 (Sea-snow POPs project).

How to cite: Pawlak, F., Koziol, K., Ruman, M., and Polkowska, Z.: Organochlorine pesticide and polychlorinated biphenyl loads in the snow cover of Hans glacier, Svalbard, IAHS-AISH Scientific Assembly 2022, Montpellier, France, 29 May–3 Jun 2022, IAHS2022-717, https://doi.org/10.5194/iahs2022-717, 2022.