ID46: Nature-based solutions to water-related risks in mountain regions
Mountain regions provide vital ecosystem services that underpin social-ecological wellbeing and health. They represent some of the most sensitive places to climate change globally and face increased risk of floods, droughts, poor water quality, glacial lake outburst floods and landslides.
Nature-based solutions (NbS) include actions which protect, manage and restore natural or modified ecosystems – providing human and ecosystem benefits. NbS comprise interventions such as forest protection, wetland restoration, terracing, infiltration ditches and ice stupas. NbS are widely advocated as a key strategy towards managing water-related risks sustainably and developing appropriate adaptation pathways. However, their application and evidence on their effectiveness in mountain regions is limited.
We welcome contributions that provide new insight into the potential for, application of, or impact of NbS in mountain environments. We encourage observation- and model-driven studies from across the natural and social sciences that consider NbS as part of transformational adaptation approaches.
Abstract ID 533 | Date: 2022-09-12 16:00 – 16:10 | Type: Oral Presentation | Place: SOWI – Seminar room SR1 |
Sansone, Stefania (1); Rosatti, Giorgio (1); Zugliani, Daniel (1); Amplatz, Thomas (2); Padovan, Alberto (1)
1: University of Trento, Italy
2: Larsech Engineering S.r.l., Sèn Jan, Trento, Italy,
Keywords: Mitigation Structures, Snow-Avalanche Hazard, Trent2d❄, Natura 2000 Site, Numerical Analyses
Snow avalanches are gravitative phenomena of snow masses that pose a potential hazard to populations living in cold mountainous regions. The classical techniques to mitigate the snow-avalanche hazard consists in constructing snow bridges or other types of snow supporting structures in the release area. Although these anti-avalanche structures effectively reduce the probability to release a snow mass, they cannot be built in potential release areas falling into protected natural sites due to constructive regulation constraints. In these cases, an alternative way to mitigate the snow-avalanche hazard corresponds to construct suitable naturalistic engineering structures in the runout zones.
In this work, we, firstly, identify some possible engineering works for a specific avalanche site belonging to the "Natura 2000" European network and, secondly, study how these engineering works can affect the snow-avalanche dynamics. For these purposes, we consider the "Val de Roseal" avalanche site (Trentino-Alto Adige, Italy) that was hit, in 1986, by an avalanche that partially destroyed some of the houses in its alluvial fan. As a preliminary step, we back-calculate the 1986 event using the numerical model TRENT2D❄ to calibrate the model parameters and highlight some interesting aspects of the avalanche site. The numerical results and a careful site inspection show how the presence in the alluvial fan of suitable vegetation and flat areas might affect the flow of a snow avalanche either by deviating or even by stopping it. To verify the capability of the vegetation and the flat areas to reduce the snow-avalanche hazard, we perform a series of simulations by modifying the topography of the alluvial fan of the study area and by considering different configurations and extent of the flat areas, different densities of the protection forests and different combinations of planes and vegetated areas. The results show that the planes act in reducing the runout distance and the dynamic pressure of the avalanche, while the vegetated areas act in deviating the avalanche flow. As regards the combination of planes and vegetated areas, this proposal overlaps the two previous effects. The planes are able to maintain the dynamic pressure in the runout zone lower than the literature limits above which the vegetated areas can be destroyed. In this way, the vegetated areas are allowed to apply their deviating effect, thus making the combination of planes and vegetated areas an effective engineering work against snow avalanches for the alluvial fan of the Val de Roseal site.
Abstract ID 134 | Date: 2022-09-12 16:10 – 16:20 | Type: Oral Presentation | Place: SOWI – Seminar room SR1 |
Balasubramanian, Suryanarayanan (1,2); Hoelzle, Martin (1); Lehning, Michael (3); Bolibar, Jordi (4); Wangchuk, Sonam (2); Oerlemans, Johannes (4); Keller, Felix (5,6)
1: University of Fribourg, Switzerland
2: Himalayan Institute of Alternatives Ladakh, Leh, India
3: WSL Institute for Snow and Avalanche Research, Davos, Switzerland
4: Institute for Marine and Atmospheric Research, Utrecht University, Utrecht, The Netherlands
5: Academia Engiadina, Samedan, Switzerland
6: ETH, Zürich, Switzerland
Keywords: Icestupa, Water Storage, Climate Change Adaptation, Geoengineering
Since 2014, mountain communities in Ladakh, India have been constructing dozens of Artificial Ice Reservoirs (AIRs) by spraying water through fountain systems every winter. The meltwater from these structures is crucial to meet irrigation water demands during spring. However, there is a large variability associated with this water supply due to the local weather influences at the chosen location. This study compared the ice volume evolution of an AIR built in Ladakh, India with two others built in Guttannen, Switzerland using a surface energy balance model. Model input consisted of meteorological data in conjunction with fountain discharge rate (mass input of an AIR). Model calibration and validation were completed using ice volume and surface area measurements taken from several drone surveys. The model was successful in estimating the observed ice volume evolution with a root mean square error within 18 % of the maximum ice volume for all the AIRs. The location in Ladakh had a maximum ice volume four times larger compared to the Guttannen site. However, the corresponding water losses for all the AIRs were more than three-quarters of the total fountain discharge due to high fountain wastewater. Drier and colder locations in relatively cloud-free regions are expected to produce long-lasting AIRs with higher maximum ice volumes. This is a promising result for dry mountain regions, where AIR technology could provide a relatively affordable and sustainable strategy to mitigate climate change induced water stress.
Abstract ID 549 | Date: 2022-09-12 16:20 – 16:30 | Type: Oral Presentation | Place: SOWI – Seminar room SR1 |
Bezbradica, Ljubiša; Milijić, Saša; Pantić, Marijana
Institute of Architecture and Urban and Spatial Planning of Serbia, Serbia
Keywords: Water Reservoirs, Floods, Soil, Forests, Environment
The growth of population and the increased demand for clean water, the reduction of living space, forests, and agricultural land, all command new, innovative means of using and managing water basins and reservoirs in the mountainous regions worldwide. Global warming and climate change have brought on large oscillation of air temperature and annual distribution of precipitation in highland regions of the Republic of Serbia as well. Prolonged dry periods are followed by frequently intensive precipitation. Such extremes result in floods and soil erosion. Among other functions, water reservoirs as major multifunctional facilities greatly affect the outflow regime. By developing them, we have the means to absorb flood flow during rainy periods, on the one hand, provide the continuous water supply to the local population, secure the ecological minimum, and prevent drying up of rivers during dry periods, on the other. Apart from affecting water regimes, newly constructed water reservoirs considerably impact the managing and use of space in the reservoir basins. This also affects biodiversity, ecosystems, and the environment in general, which is thought to be degraded in half the territory of the Earth. Introduction of protection measures, restrictions, and prohibitions considerably affect land resources, resulting in the increased forest areas, planned management of agricultural land, prevention of unnecessary construction and opening of mines, as well as other activities that cause water shortage and pollution, soil erosion, accumulation of mud deposits, and similar. Constructing embankments and water course regulation downstream reservoirs partly reduce flooding issues, as opposed the accumulation of deposits and prolonged dry periods, still largely present. This commands the integral analysis of the mountain basins issue and the preparation of technical, space planning documentation, and feasibility studies for building new water reservoirs as economically, socially, ecologically, and environmentally sustainable systems. The Republic of Serbia has recognised the significance of building water reservoirs in mountainous regions, and has devoted itself to protecting and preserving the existing and planning the new water reservoirs.
Abstract ID 699 | Date: 2022-09-12 16:30 – 16:40 | Type: Oral Presentation | Place: SOWI – Seminar room SR1 |
Gribbin, Tom (1,2); Mackay, Jonathan (1,2); Hannah, David (2); Buytaert, Wouter (3); Macdonald, Alan (4); Román-Dañobeytia, Francisco (5); Drenkhan, Fabian (6,3,7)
1: British Geological Survey, Keyworth, Nottinghamshire, UK
2: School of Geography, Earth & Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
3: Department of Civil and Environmental Engineering, Imperial College London, London, UK
4: British Geological Survey, Lyell Centre, Edinburgh, UK
5: Consorcio para el Desarrollo Sostenible de la Ecorregión Andina (CONDESAN), Calle Codornices 253 – Surquillo, Lima 34, Peru
6: Department of Humanities, Pontificia Universidad Católica del Perú, Lima, Peru
7: Department of Geography, University of Zurich, Zurich, Switzerland
Keywords: Wetland, Nbs, Melt, Andes, Groundwater
Peru has been ranked as one of the top 10 most water abundant places in the world for freshwater resources; however this masks the acute spatial (mountain – coast) and temporal (dry – wet season) disparity in water supply. Seasonal water storage and release dynamics of glacial and non-glacial stores in the tropical high Andes modify the water availability to the more densely populated lowlands where demand for water is higher. In parts of the high-Andes, meltwater from glacierized headwaters provides an important additional source of supply throughout the dry season. The mosaic of water stores in these catchments requires investigation in terms of space-time dynamics, and especially in relation to the high-altitude wetlands known locally as 'bofedales', which may be significant sites of surface water – groundwater exchange.
For generations local people have made use of the pastures provided by these wetlands, adapting to pressures on supply and demand through livestock rotation and modifications to the drainage network. Maintaining and extending wetlands has been an effective 'nature-based solution' for water security at the local scale, but the potential benefits of replication at the regional scale are not well understood, in part because the water source dynamics are poorly known. Whether local communities are able to adapt to shrinking glacial contributions and changing precipitation patterns under climate change will also depend on the contributions of these inputs to wetlands.
Whilst remote sensing-based studies have postulated an association between peak glacial melt and downstream wetland extent, field-based studies downstream of glacierized catchments have suggested minimal connectivity between melt-dominated streams and nearby wetlands. However, in the headwaters, exchanges between glacial melt streams, deeper groundwater stores, and wetlands may be an important mechanism of connectivity.
To understand the processes by which glaciers influence the hydrological behaviour of high-altitude wetlands, we take a nested catchment approach at the subcatchment, catchment and basin scale, comparing wetlands at different positions in the landscape and with differing glacial contributions. We present the initial results from campaign sampling of stable isotopes, geophysical mapping of the subsurface, and low-cost water level sensors in order to address the following question:
How does the contribution of glacial melt to wetland water and streamflow vary at different positions in the landscape, and what does this tell us about the optimal locations for storing water?