И преди съм писал по темата, но там акцентът беше по-скоро върху изпарението и загубата на вода във водосбора на реките.

От гледна точка на фитоценолозите проблемът има и други измерениея. Обработката на ски-пистите с изкуствен сняг и с машини, водят до:
1. На по-високите части до намаляване видовото богатство, на покритието на растителността и т.н.
2. На по-ниските части - увеличаване на мезофитизацията (т.е. повишаване на овлажняването на почвата), намаляване на видовото богатство, но увеличаване на продуктивността, като това се дължи на заместването на типичните алпийски и субалпийски видове, и особено храстите (заради машините), с рудерали-нитрофили, харесващи богати на азот почви!

На места има и засоляване от изкуствения сняг, което също намалява видовото богатство.

Всички препоръки са в консервационно-значими територии да не се правят писти.

Темата е била представена от италианския учен Сара Казагранде на конгрес на фитоценолозите от European Vegetation Survey през лятото на 2017г в Билбао

Floristic changes in subalpine grasslands after 22 years of artificial snowing

https://doi.org/10.1078/1617-1381-00012 Get rights and content

Abstract

Global warming affects snow reliability in many winter sports resorts between 1200 and 1800 m a.s.l. in the European Alps. To deal with this problem, tourism managers consider guaranteeing winter sports by intensifying artificial snow-making. However, the knowledge of the impacts of artificial snow on ecosystems and especially on vegetation is still rudimentary. The aim of this study was to investigate whether artificial snowing leads to detectable quantitative and qualitative changes in the floristic composition of upper montane and subalpine meadows and pastures. In Savognin (eastern Swiss Alps), where artificial snow-making occurred every year since 1978, ten transects were laid perpendicular to the artificially snowed ski run between 1190 and 1780 m a.s.l. Each transect consisted of two to six plots in the artificially snowed area and five to eight plots on its left and/or right side. Vegetation censuses were made in 1987 (cover data) as well as in 1988 and 2000 (presence/absence data). A phytosociological survey of the general study area was accomplished in 1988. Air permeability and ion content of the artificial snow cover were also analysed. The results suggest that artificial snow leads to detectable changes in the floristic composition as well as to a decrease in species richness of the communities involved. In particular, the additional inputs of water and ions seem to alter the competition balance in the communities, promoting the faster growing species characteristic of nutrient-rich, mesic habitats at the expense of weaker competitors such as the species of low-nutrient and drier habitats. In conclusion, artificial snow represents a serious threat for the plant species diversity of low-nutrient and dry grasslands.

Impact of artificial snow and ski-slope grooming on snowpack properties and soil thermal regime in a sub-alpine ski area

Article · January 2004 with 111 ReadsDOI: 10.3189/172756404781815310

Abstract

Earlier studies have indicated that the soil on groomed ski slopes may be subjected to more pronounced cooling than the soil below a natural snowpack. We ana-lyzed the thermal impacts of ski-slope preparation in a sub-alpine ski resort in central Switzerland (1100 m a.s.l.) where artificial snow was produced. Physical snow properties and soil temperature measurements were carried out on the ski slope and off-piste during winter 1999/2000. The numerical soil^vegetation^atmosphere transfer model COUP was run for both locations, with a new option to simulate the snowpack development on a groomed ski slope. Snow density, snow hardness and thermal conductivity were signifi-cantly higher on the ski slope than in the natural snowpack. However, these differences did not affect the cooling of the soil, since no difference was observed between the ski slope and the natural snow cover. This might be because cold periods were rare and short and thus any snowpack could protect the soil from freezing. The major impact of the ski-slope grooming was a 4 week delay in snowmelt and soil warming at the end of the season. The newly implemented option proved to be a useful strategy for simulating the snowpack of a ski slope. However, snow density was underestimated by the model as it could not account adequately for compaction due to grooming traffic. Our study demonstrates that there is no site-independent answer as to whether a groomed snowpack affects the thermal condi-tions in the soil.

Impact of artificial snow and ski-slope grooming on snowpack properties and soil thermal regime in a sub-alpine ski area (PDF Download Available). Available from: https://www.researchgate.net/publication/228747508_Impact_of_artificial_snow_and_ski-slope_grooming_on_snowpack_properties_and_soil_thermal_regime_in_a_sub-alpine_ski_area [accessed Sep 25, 2017].

Does artificial snow production affect soil and vegetation of ski pistes? A review

https://doi.org/10.1078/1433-8319-00036

Abstract

The production of artificial snow and the use of snow additives in ski resorts have increased considerably during the last 20 years. Their ecological consequences are the subject of environmental concerns. This review compiles studies about the ecological implications of ski pistes preparation in general and of artificial snow production. The main direct impacts of ski piste preparation on the vegetation are related to the compaction of the snow cover, namely the induction of soil frost, the formation of ice layers, mechanical damage and a delay in plant development. The vegetation reacts with changes in species composition and a decrease in biodiversity. Artificial snowing modifies some of these impacts: The soil frost is mitigated due to an increased insulation of the snowpack, whereas the formation of ice layers is not considerably changed. The mechanical impacts of snow-grooming vehicles are mitigated due to the deeper snow cover. The delay of the vegetation development is enhanced by a considerably postponed snowmelt. Furthermore, artificial snowing induces new impacts to the alpine environment. Snowing increases the input of water and ions to ski pistes, which can have a fertilising effect and hence change the plant species composition. Increasingly, snow additives, made of potentially phytopathogenic bacteria, are used for snow production. They enhance ice crystal formation due to their ice nucleation activity. Although sterilised, additives affected the growth of some alpine plant species in laboratory experiments. Salts are applied not only but preferably on snowed pistes to improve the snow quality for ski races. The environmental impacts of most salts have not yet been investigated, but a commonly used nitrate salt has intense fertilising properties. Although snowing mitigates some of the negative impacts of ski piste preparation in general, new impacts induced by snowing could be non-beneficial to the vegetation, which, however, has yet to be clarified.

The Regents of the University of Colorado, a body corporate, contracting on behalf of the University of Colorado at Boulder for the benefit of INSTAAR

Influence of Vegetation, Temperature, and Water Content on Soil Carbon Distribution and Mineralization in Four High Arctic Soils Author(s): Bo Elberling, Bjarne H. Jakobsen, Peter Berg, Jens Søndergaard, Charlotte Sigsgaard Reviewed work(s): Source: Arctic, Antarctic, and Alpine Research, Vol. 36, No. 4 (Nov., 2004), pp. 528-538 Published by: INSTAAR, University of Colorado Stable URL: http://www.jstor.org/stable/1552307 . Accessed: 02/11/2011 08:55 Soil organic matter distributions, reservoirs, and mineralization rates in tundra soils are important factors for understanding biogeochemical carbon cycling. This study focuses on spatial trends and environmental controls of soil carbon distribution and microbial soil respiration in 4 tundra vegetation communities in an arctic valley in NE-Greenland (74?N), including Dryas and Cassiope heaths, Salix snow bed, and fen vegetation. Measured total soil organic carbon in the upper 50 cm averaged (+SD) 11.0 ? 1.5 kg C m-2 with spatial variations strongly affected by vegetation, hydrology, and buried organic layers. Observed soil CO2 concentrations and effluxes were simulated with a steady-state diffusion model using laboratory measured CO2 productions as input. Simulated CO2 profiles and CO2 effluxes (up to 3 tmol CO2 m-2 s-1) agreed with field observations and revealed the importance of both vegetation- and depth-specific CO2 production and CO2 diffusion for understanding the spatial variation in near-surface soil CO2 gas dynamics. These results confirm that molecular diffusion dominates gas transport in the studied soils; but also that the complexity of CO2 production/transport coupled to soil heterogeneity (in particular the litter layer) complicates the application of soil-diffusion models to estimate seasonal trends of soil gas effluxes https://blogs.uoregon.edu/fonstad/files/2015/10/Lillquist_Walker_2006-1li1zbf.pdf

Skiing and Vegetation
Christian Rixen*
WSL Institute for Snow and Avalanche Research SLF, Flüelastrasse 11, 7260
Davos Dorf, Switzerland
Abstract: Impacts of skiing on alpine and subalpine vegetation are expressed by
multiple disturbances: snow is being compacted by skiers and heavy machinery, new
ski pistes are constructed by means of machine-grading and, increasingly, artificial
snow is being produced by snow-making facilities.
This review compiles studies on ski piste vegetation from more than three centuries and
skiing destinations across the world and distinguishes between different types of
disturbances and elevations. Skiing in general can exert disturbances in the vegetation
because of the changed snow conditions. The compaction of the snow can induce hard soil
frost and mechanically damage plants. Machine-grading in summer to create smooth
surfaces represents the most drastic disturbance on ski pistes especially at elevations around
and above treeline. Artificial snow production has the potential to change vegetation
through an input of water and ions and through postponing the time of melt-out.
Restoration measures to re-establish local vegetation after machine-grading have improved
considerably in the last decades, however, still the vegetation and soil rarely fully recovers
after major disturbance. If constructions are unavoidable, it is vitally important that
restoration measures follow restoration guidelines that represent today’s state of the art.

Keywords: Alpine vegetation, artificial snow, machine-grading, restoration, ski-
piste construction, snow, snow-making.

INTRODUCTION
Winter tourism has become a major economic factor in many mountain regions of
the world [1], and especially downhill skiing represents the economically most
important activity in resorts for winter sports. However, downhill ski areas can
have dramatic effects on vegetation and, as a result, the esthetics of the landscape.
Numerous studies have looked intensively into skiing effects on vegetation for
*Address correspondence to Christian Rixen: WSL Institute for Snow and Avalanche Research SLF,
Flüelastrasse 11, 7260 Davos Dorf, Switzerland; Tel: ++41 81 4170214; Fax: ++41 81 4170110; E-mail:
rixen@slf.ch

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2664.2005.01011.x/full

Long-term impacts of ski piste management on alpine vegetation and soils

First published: 23 February 2011Full publication history
DOI: 10.1111/j.1365-2664.2011.01964.x View/save citation
Cited by (CrossRef): 16 articles Check for updates
Correspondence author. E-mail: rixen@slf.ch

Summary

1. Downhill skiing, the machine-grading of slopes and the use of artificial snow induce major disturbances to the environment of alpine ski resorts. Our study aims to quantify the impacts of different ski piste management types (graded/ungraded; with/without artificial snow) on the environment and its development over time.
2. We re-sampled study plots established 8 years earlier and compared vegetation and soil characteristics on different types of ski pistes to adjacent off-piste control plots, and analysed vegetation changes over time.
3. Generally, machine-grading led to a decreased plant cover and plant productivity, and increased indicator values for nutrients, light and soil base content compared to control plots. Ungraded ski pistes and artificial snow led to increased vegetation indicator values for nutrients and soil humidity.
4. Soil analyses conducted in 2008 generally confirmed the changes shown by the vegetation indicator values in 2000 and in 2008. Machine-grading had the greatest effects on soil characteristics by increasing soil density by more than 50%, by increasing pH and C/N ratio, and by decreasing total nitrogen concentrations.
5. The differences between piste and off-piste plots were similar to those found 8 years ago, but their proportions changed. The vegetation cover on machine-graded ski pistes decreased over the 8 years, showing no sign of recovery or succession. Ungraded ski pistes showed increased differences in indicator values for reactivity and humus between piste and control plots compared to the results obtained 8 years earlier.
6. Synthesis and applications. Machine-grading of ski runs and downhill skiing in general induced long-lasting impacts on vegetation and on both chemical and physical soil characteristics. Even though few impacts of artificial snow were significant, our results suggest that it may change moisture status of the vegetation, and thus caution is warranted when used in dry and nutrient-poor habitats. The vegetation cover on machine-graded pistes deteriorated over a period of 8 years, illustrating that natural recovery did not occur in these alpine habitats. Consequently, the construction of new pistes by machine-grading in alpine habitats should be avoided, and existing pistes should be managed to avert further disturbances.

Effects of ski piste preparation on alpine vegetation

SONJA WIPF*†, CHRISTIAN RIXEN*†, MARKUS FISCHER‡, BERNHARD SCHMID† and VERONIKA STOECKLI*

WSL Swiss Federal Institute for Snow and Avalanche Research SLF, Flüelastr. 11, 7260 Davos Dorf, Switzerland;

†

Institute of Environmental Sciences, University of Zurich, Winterthurerstr. 190, 8057 Zurich, Switzerland; and

‡

Institute of Biochemistry and Biology, University of Potsdam, Villa Liegnitz, Lennéstr. 7a, 14471 Potsdam, Germany

Summary1.

Ski resorts increasingly affect alpine ecosystems through enlargement of ski pistes,machine-grading of ski piste areas and increasing use of artiﬁcial snow.

In 12 Swiss alpine ski resorts, we investigated the effects of ski piste management onvegetation structure and composition using a pairwise design of 38 plots on ski pistesand 38 adjacent plots off-piste.

Plots on ski pistes had lower species richness and productivity, and lower abundanceand cover of woody plants and early ﬂowering species, than reference plots. Plots onmachine-graded pistes had higher indicator values for nutrients and light, and lowervegetation cover, productivity, species diversity and abundance of early ﬂowering andwoody plants. Time since machine-grading did not mitigate the impacts of machine-grading, even for those plots where revegetation had been attempted by sowing.

The longer artiﬁcial snow had been used on ski pistes (2–15 years), the higher themoisture and nutrient indicator values. Longer use also affected species composition byincreasing the abundance of woody plants, snowbed species and late-ﬂowering species,and decreasing wind-edge species.

Synthesis and applications.

All types of ski piste management cause deviations fromthe natural structure and composition of alpine vegetation, and lead to lower plant speciesdiversity. Machine-grading causes particularly severe and lasting impacts on alpinevegetation, which are mitigated neither by time nor by revegetation measures. Theimpacts of artiﬁcial snow increase with the period of time since it was ﬁrst applied to skipiste vegetation. Extensive machine-grading and snow production should be avoided,especially in areas where nutrient and water input are a concern. Ski pistes should notbe established in areas where the alpine vegetation has a high conservation value.

Key-words

:artiﬁcial snow, biodiversity, functional groups, machine-grading, snowecology, Switzerland

Journal of Applied Ecology

(2005)

, 306–316doi: 10.1111/j.1365-2664.2005.01011.x
http://www.academia.edu/24032144/Effects_of_ski_piste_preparation_on_alpine_vegetation

The production of artificial snow - ecological, social
and economical aspects
Julia Snajdr
B.Sc. International Forest Ecosystem Management, HNEE Eberswalde
Master Student Mountain Forestry, University of Life Sciences and Natural Resources
Vienna
Traineeship as a junior producer (motion picture), FECHNER Media in Baden Württemberg
Contact: Julia@snajdr.de, http://www.juliasnajdr.de/
2
Structure
1. Introduction .................................................................................................................... 3
2. Impact on flora and soil .................................................................................................. 4
3. Impact on fauna.............................................................................................................. 6
4. Impacts concerning water ............................................................................................... 6
a. Effect on water pollution and -quality .......................................................................... 6
b. Reasons for a lack of data concerning water extraction .............................................. 7
c. The period of water extraction and return to the water cycle ....................................... 9
d. Quantity of water abstraction, water release and water loss to the athmosphere .......10
5. Ski accidents related to artificial snow density ...............................................................13
6. Financial aspects concerning artificial snow production .................................................13
7. Outlook ..........................................................................................................................14
3
1. Introduction
In the Alps, the temperature raises nearly three times faster compared to average global
warming. Since 1985 the amount of drinking water drained from the Alps has declined by a
quarter (DIE WOCHENZEITUNG (2011)).
Since the mid-1980s, snowfall has been decreasing considerably in the northern
hemisphere, particularly in mountain regions. Some regions in the Alps have been losing four
meters of average snow depth over the past 30 years. Frequently temporal and spatial snow
cover on ski runs decreased to such an extent that continuous skiing during the winter
season was no longer possible. Many ski resorts at low altitude in the European Alps are
expected to have very little snow left within the next 1-2 decades (De Jong, C. (2009) (2)).
According to Prof. Dr. Wolfgang Seiler of the Institute of Meteorology and Climate Research,
Atmospheric Environmental Research (IMK-IFU), the mean winter temperature is going to
rise by 4 to 5°C, leading to an elevation of the zero degree line by 150 meters per +1°celsius
(Doering, A. et al 1996).This line has risen by 300 meters due to an increasing temperature
of 2°C during the last 50years (Canadarges (2010)).
In the next 25 to 50 years the orographic snow line of ski areas with guaranteed snow is
going to rise to 1 200 – 1 500 meters above sea level (Rixen et al 2002). With a temperature
increase of 1.3 to 6°C until the end of the century, the lower boundary for the production of
artificial snow could rise by 250m to 1 000m a.s.l. (De Jong, C. 2010).
The first snow cannons were erected in the Austrian Alps already in the beginning of the
70ies, followed by Switzerland in 1976 and Germany in 1987 (Doering, A. et al 1996).The
number of constructions producing artificial snow as well as the use of chemical substances
has increased constantly, although the artificial snow production had severe ecological
effects (Doering, A. et al 1996).    The demand of the preparation of snow at any time is
pushed by the commercialization of skiing and large scale events as the Ski World Cup. The
time of producing artificial snow is often not adapted to climate- and weather conditions but
rather to the demands of sport goods industry, tourism and television (Rixen, Ch. et al 2002).
4
2. Impact on flora and soil
The production of artificial snow impacts the vegetation period, regeneration, forest stands
stability and contributes to species change and – freeze.
The vegetation period is altered by the insertion of artificial snow, remaining two to three
weeks longer on the slopes as the natural snow cover. Accordingly, plant growth is delayed
and species, typically found in regions of late deglaciation, augment at slopes of artificial
snow (Schneetälchenarten). In general, species diversity and productivity is minimized
compared to undisturbed areas (Rixen et al 2002). Pröbstl (2006) concludes that there is a
modification in species and a permanent change in the plant communities. Thus above 1 200
meters the vegetation period is reduced to such an extent that regeneration is often not
possible and soils and slopes degenerate from year to year. Commonly, the most important
threshold is the forest boundary. Alpine meadows above this boundary mostly do not have
the time and capacity to regenerate. They experience climatic and environmental conditions
comparable to the Arctic. As for the Arctic, these mountain zones take hundreds of years to
recover from landscape modification such as pipelines and reservoirs. High altitude forest will
also take decades to regenerate (De Jong, C. (2009) (2)).
Soil temperature under the artificial and natural snow cover is differing. It ranges from 0°C
under artificial snow cover and undisturbed snow cover and -10°C under the compressed
natural snow cover. Species adapted to high alpine peaks with little snow cover
(“Windheidearten”) have increased significantly at slopes of natural snow (Rixen, Ch. et al
2002).
Under the dense artificial snow layer, particularly during ice formation, the oxygen content
decreases followed by decomposition and an infestation by black snow mold (Herpotrichia
juniper). In addition, plants get more prone to frost. As a consequence they freeze to death at
temperatures which they are usually not harmed by (Doering, A. et al (1996)). Furthermore,
vegetation is havocked by the freezing temperatures in the immediate vicinity of artificial
snow canons (De Jong, C. (2009) (2)).Regeneration of trees at the forest edges is harmed by
the salting used to defrost forest roads for the transportation of artificial snow. The harming
effect is aggravated by the complete extraction of remaining snow and the passing over the
slopes during the process of melting (Doering, A. et al 1996). Especially the stability of the
bordering trees of the remaining stand is minimized by defects in the rooting zones by
construction works. Forest aisles providing space for lifts make stands more susceptible to
wind breaks and other atmospheric conditions.
5
During the production of the artificial snow wind-blown dispersal leads to its accumulation in
adjacent stands, resulting in snow breakage and the enrichment of nutrients which are distributed
in the forest during snow melt.
The production of artificial snow contributes to erosion effects and impacts grassland and
wetlands. The melting water of artificial snow contains four times more minerals and nutrients
than the melting water of natural snow. Consequently generalist species utilizing the
provision with more nutrients increase beneath slopes with artificial snow (Rixen, Ch. et al
2002)). These less adapted and unstable species lead to an increase in erosion and
consequently to a cutback of species diversity (Doering, A. et al (1996)).
Various consequences of artificial snow fabrication on soil conditions have been determined.
The production of artificial snow comprises the hauling of electricity-, clime- and water tubes
in ditches. The massive territorial impacts cause the disruption or loss of vegetation , humus
layer and soil activity. The regeneration of soil and vegetation in susceptible mountain
ecosystems could take decades or even centuries. Leveled slopes are more suitable for the
provision with artificial snow than natural terrain. But the leveling of slopes is a severe
intervention in the soil structure, vegetation and land form.   Both, large scale construction
sites and leveling are rarely implemented with site specific plant communities and the
success of laborious restoration often undetermined.
Through the production of artificial snow the total amount of melting water rises up to 200
l/m
2
. Due to its higher density, the amount of melt water of artificial snow is two times higher
than of natural snow. Consequently erosion is increased locally at sites of inappropriate
vegetation and soil condition. The minimum standard resulting from scientific investigations is
80% crown cover of site specific vegetation and sufficient root penetration. These demands
are not met at most slopes (Doering, A. et al (1996).Models show that these circumstances
lead to an increased flooding probability of 30% and an enhancement of erosion (De Jong,
C. (2010)). The greater hardness and density of artificial snow compared to natural snow
also causes the top soil to become compressed and impermeable (Rixen, Ch., Haeberli, W.,
and Stoeckli, V. (2004) in De Jong, C. and Barth, T. (2007).
The increase of melting water intensifies the problematic of already existing slope water at
lower elevations. Together with the delayed melting of artificial snow especially at shadowy
sites it is a concern for agriculture. Especially species-rich meadows, dry- and neglected
6
grassland, and wetlands are harmed severely at all altitudes (KAMMER & HEOG 1989,
HOLAUS u. PARTL 1994 in Wechsler, H.G. (1989)).
3. Impact on fauna
During winter time, Lyrurus tetrix and Tetrao urogallus are need to conserve energy and are
vulnerable to disturbances. The noise of snow making facilities as well as night-time
illumination is severely threatening the preservation of these species. Regarding Cervus
elaphus, the extreme fragmentation of the habitat is a challenge. The possibility of feeding is
cut off just in the times of food shortage from mid November until the beginning of March. In
the Western Italian Alps lower bird species richness was detected in coniferous forests due
to noise and disturbance from ski runs (Laiolo and Rolando 2005 in De Jong, C. (2009)).
Water organisms are endangered by the excessive water extraction and the dehydration of
shore edges or the whole river bed.
4. Impacts concerning water
a. Effect on water pollution and -quality
The chemical composition of the water used for the production of artificial snow is a danger
as spring- and drinking water contains much more minerals than rain and snow, thus causing
fertilizing effects (Doering, A. et al (1996)).
The water quality is changed to a higher mineral content (De Jong, C. 2009 (2)). The
concentration of magnesium is 40 times higher in artificial snow and for calcium it is 10 times
higher (De Jong, C. 2010). The mineral and ion concentration in artificial snow melt water is
four times higher than in neighboring streams causing a local fertilizing effect (Rixen and
Steockli 2000). This directly effects vegetation growth and species diversity by promoting
more woody plants, shrubs and weeds (De Jong, C. (2009) (2)).
Furthermore, the water output from streams and rivers can benefit the spreading of
pathogens and contaminants, in the long run possibly not only affecting soils and vegetation
but also spring- and subterranean water (Doering, A. et al (1996)). The quality of melt water
from artificial snow is not comparable to the drinking water standards initially used for its
7
production. Sanitary risks due to bacteria may be a consequence of the long period of
stagnation in reservoirs and pipelines (AFFSET (2008)).
Additional substances are admixed to the water to maintain artificial snow at temperatures
above 0C°. Skin diseases and pneumonia are consequences for staff member responsible
for the snow cannons (DIE WOCHENZEITUNG (2011)).
In some regions of the Alps the US bacteria Pseudomonas syringae is introduced into the
water to be able to produce artificial snow at higher temperatures. The bacteria are
inactivated through radioactive radiation and then utilized as crystallization germs to safe
energy (ROCHLITZ 1989 in Doering, A. et al (1996)). The use of these bacteria is still
prohibited in Germany but they are generally hard to detect. The outer membrane of
Pseudomonas syringae contains lipopolysaccharides, which correspond to endotoxins. The
high concentration of endotoxins (>90 unit of endotoxins per m³) near snow canons can
provoke hemodynamic and inflammatory diseases as well as fever, shortness of breath,
coughing fits and dysfunctions of respiration organs (De Jong, C. (2010)).
Another factor lowering water quality is regarded concerning stream discharge. A discharge
that is lower than the minimum defined discharge can menace the survival of flora and fauna
as well as lowering the water quality (De Jong, C. (2009) (2)).
AFSSET (Agence Francaise de Securite Sanitaire de l`Environnement et du Travail)
recommends to use water of good microbiological quality for the production of artificial snow
to preserve the water quality, especially the water intended for human consumption
(SePT/ACPT (2009)).
b. Reasons for a lack of data concerning water extraction
Analytical models and methods applied to evaluate development effects are often unsuitable
for montane settings as they lack algorithms to treat snow pack accumulation and ablation. A
range of hydrologic processes obscured through empirical approaches to rainfall and runoff
relationships and are, due to a lack of a high-elevation monitoring network, largely
unvalidated against observed conditions (Wemple, B. et al (2007)).
8
In the environments of high altitudes, liquid water is not omnipresent as it is mostly frozen or
prevalent below the subsurface. Further difficulties are the representativeness of sites in
remote locations and the effects of extreme weather events (De Jong, C. and Barth, T.
(2007)). The measurement of classical hydrological components such as precipitation,
discharge and evapotranspiration is rare and terrestrial photogrammetry or remote sensing
are not purposefully applied (De Jong, C. & Barth, T. (2007)).
In the following, terrestrial and aerial photography, remote sensing, satellite images , and
radar methods are examined.
The ablation of the prolonged snow cover from ski runs with artificial snow can be measured
by terrestrial photography. The reservoirs are increasingly built at high altitudes where
surface and runoff water is naturally limited (De Jong, C. and Barth, T. (2007)). Terrestrial
photography together with accurate Digital Elevation Models (DEMs) can be applied to
monitor daily snow cover and evaluate snow water equivalent from ski runs at low installation
costs.
Unless too outdated, aerial photography and Google Earth or IGN images provide a precise
method for field orientation and establishment of status quo of ski resort development but are
inadequate for continual monitoring or establishing a pre-development stage. Remote
sensing has been applied to discover changes in glacier extents and snow cover and serves
as a tool to overcome the remoteness of most sites but also to represent the vast variability
of small-scale topography. However, as water phenomena occur on a sub-basin scale,
suitable remote sensing techniques have to be adapted or developed. Additionally, airborne
remote sensing from either small aircrafts or ultralight trikes should be applied regularly to
collect relevant meteorological data. Air humidity can be used as an indicator of evaporation
from artificial snow and detailed images could be obtained during the process.
Artificial snow is highly variable over time and altitude. This makes derivations form satellite
images almost impossible if grid size resolutions around 15 m at high temporal resolution are
not available. Yet the changeable weather conditions on montane areas pose a great
challenge to the application of remote sensing.
A common difficulty is that inventories of humid zones were not conducted before water
retention reservoirs for snow production were build and that the resolution of remote sensing
images is not high enough which makes it difficult to reconstruct the situation nowadays (DIE
WOCHENZEITUNG (2011)).
9
For example, one problem associated with snow water reservoirs for artificial snow
production is the lack of high resolution images showing the extent of wetlands or lakes that
existed prior to their construction. These reservoirs are increasing rapidly in number. Radar
inferometry should provide useful information for monitoring the filling levels of these
reservoirs for hydrological monitoring and to establish the thickness of snow cover on the ski
runs.
Radar methods should provide data about the filling levels of new reservoirs build to store
water for the production of artificial snow (De Jong, C. and Barth, T. (2007)).
The intensification of snow monitoring through snow pillows or snow lysimeters is essential
(De Jong C., Masure P., Barth T. (2008)).
A special semi-distributive module for the simulation of snowmelt was developed by Barth
based on the degree-day method and classified according to 100 m iso-altitudinal bands. Its
input parameters consist of temperature, precipitation, daily snow melt and contribution of
artificial snow. The surfaces covered by artificial snow are subdivided into different altitudinal
bands together with the amount of water necessary to produce the snow. The altitudinal
bands with artificial snow are adapted to those with natural snow, so that the excess in water
produced by snowmelt from artificial snow is added to the natural torrent regime (De Jong, C.
and Barth, T. (2007)).
c. The period of water extraction and return to the water cycle
The water for artificial snow production is taken during the season where water resources are
naturally at their lowest in the Alps. The water withdrawal coincides with a period when tens
of thousands of tourists accumulate in few big skiing areas, consuming water for cooking,
showering and bathing (DIE WOCHENZEITUNG (2011)).
The water is mainly extracted in seasons with extreme low water level with climatologic frost
periods. The water abstraction is highest when artificial snow production reaches its
maximum at degrees of -11°C (Wechsler, H.G. (1989) in Doering, A. et al (1996)). Besides
10
streams, rivers and springs even the drinking water supply is affected (Doering, A. et al
1996).
In general, the return of the water extracted for snowmaking to the water cycle is delayed by
8-10 months (De Jong C., Masure P., Barth T. 2008).
d. Quantity of water abstraction, water release and water loss to the
athmosphere
In average, the snow cover of artificial snow is 70cm higher compared to the snow cover of
natural snow and it contains double as much water (Rixen, Ch. et al (2002)).The more water
the artificial snow contains the denser it is. It can be four times heavier than new snow or
primed snow (Doering, A. et al (1996)).
- Water extraction -The water consumption amounts to 200-600 l per square meter and season for “basic
artificial snow cover” (Grundbeschneiung) and “additional snow making” (Nachbeschneiung)
(Doering, A. et al (1996)).
In the test area of Bourg-Saint-Maurice in Savoy, France, approximately 200 000 m
3
water
are consumed annually to cover 58ha of ski runs (De Jong, C. and Barth, T. (2007)).
One m³ of water is sufficient to produce 2.2m³ of artificial snow (OPINION (2012)). In the
Austrian and Swiss Alps, between 20-40% of the total annual water consumption is taken for
snow production, which correlates with more than 50% of the total drinking water
consumption (Teich et al 2007; Vanham et al 2008 in De Jong, C., Masure P., Barth T.
(2008)).
In some regions of the French Alps more than 50% of the available drinking water is directly
used for snow production at a daily scale. The minimum low flow discharge can be reduced
by up to 75% during the winter as a consequence of the abstraction of artificial snow
(Strasser 2008; Campion 2002 in De Jong, C., Masure P., Barth T. (2008)).
Modern snow producing machines produce 96 m³ artificial snow per hour with a water
consumption of 638 l per minute (De Jong, C. (2010)).
Per year and hectare of artificial snow, 3 300 m³ water are consumed (De Jong, C. (2010)).
11
For the production of two m³ of artificial snow, one m³ of water is needed (ODIT France,
2008a in SePT/ACPT (2009)).
In average, 3500m³ water per ha and year are necessary for the production of artificial snow
for a skiing area (ODIT France, 2008b in SePT/ACPT (2009)).
Water is increasingly stored in new, high alpine artificial snow water reservoirs with
dimensions resembling medium-size dam reservoirs (De Jong C., Masure P., Barth T.
(2008)).
In the French Alps, more than one third of the resorts experience shortages in water supply
for domestic uses because in 25% of resorts, snow production competes with human uses
consumption (Bravard 2008 in De Jong, C. (2009).
The artificial production of snow is a problem for the local drinking water supply, qualitatively
and quantitatively. In the whole Alps, the area covered by artificial snow increased from 24
000 ha in 2007 to 50 000 ha in 2011. The amount of water used for the manufacture more
than doubled within three years. Half of the resources originate from water storing reservoirs,
further from local streams, lakes, ground water and drink ing water sources (DIE
WOCHENZEITUNG (2011)).
Snow making requires quantities which are locally not available. Technological investment
are often necessary to supply and establish large artificial water reservoirs with sizes up to
400 000 m³ (De Jong, C. (2009) (2)).
The quantity of water removal is determined, but can´t be controlled during winter time.
Only 5-10% of the water stored in reservoirs for the production of artificial snow comes
directly from precipitation, the rest is provided by pumping up over hundreds of meters height
difference and dozens of kilometers (OPINION (2012)).
- Water release -
Through the production of artificial snow the total amount of melting water rises to about 200
l per m
2.
12
Six torrents were compared regarding their natural and artificial snow melt-induced
discharge. The difference was negligible for the month September to February; largest
distinctions were modeled for July and August with the increase of nearly one third. Seasonal
impacts of artificial snow extent far into the summer season and are of particular concern
after May. For all scenarios, there is a 20-30% increase in discharge between the months of
May to August and between 3-5 % decreases in discharge for the months of February to
April due to the delay of the melting of artificial snow.
- Water loss –
Water agencies and water tax offices assume that between 30-50% of water can be lost by
evaporation related to snow production including the retention in reservoirs, the process of
actual snow production and the sublimation and evaporation from the snow surface (De
Jong, C. 2007 in De Jong, C., Masure P., Barth T. (2008)).
High water losses through evaporation (on average 30%) are to be expected from snow-making. The main sources of water losses by evaporation are the artificial reservoirs storing
water at high altitudes in liquid form throughout the year. This does not correspond to the
natural hydrological situation, where, under highly permeable conditions, water is transported
and stored mainly at the sub-surface and is frozen in winter, protecting it from evaporation.
Another cause of evaporation is the snowmaking process itself (Arabas, S. et al 2008 in De
Jong, C. (2009) (2)).
In order to form snow from water, it has to be cooled and condensed. This cooling
requires evaporation. When conditions are windy and dry and manufactured snow is
transported particularly high into the atmosphere, considerable amounts of water are lost
through evaporation. A final source of water loss is by sublimation and direct evaporation
from the snow surface during long periods of prolonged snow cover. As the snow melts, it is
prevented from infiltrating into the highly compact snow column and stagnates at the surface.
This makes it vulnerable to evaporation. The water lost by evaporation can easily leave the
catchment and no longer be available for discharge and local use. Dirmeyer et al (2008)
found that nations with mountainous terrain, a humid climate or at high altitudes are   those
that have the highest import and export ratio of atmospheric water vapour. Thus ski areas
are particularly prone to atmospheric water exchange (De Jong, C. (2009) (2)).
13
In China, evaporation under the low relative humidity is high, thus the sublimation of snow
(direct loss of snow by evaporation into the atmosphere) on the ski runs is high. Losses from
artificial snow in the order of 50% can be expected under these arid conditions (De Jong, C.
(2009) (2)).
Water and important nutrients are stored as artificial snow over many months and at the
same time subjected to high evaporation losses and delayed snow melt (De Jong C., Masure
P., Barth T. 2008)).
5. Ski accidents related to artificial snow density
With a density of 300-500 kg/m³, artificial snow is four times harder than natural snow (De
Jong, C. 2010). In the papers on hand no information about ski accidents has been found.
6. Financial aspects concerning artificial snow production
The construction of a snow making systems with subterranean development cost one million
Swiss Francs per kilometer (DIE WOCHENZEITUNG (2011)).
In France, 20% of the skiing pistes are covered by artificial snow and represent 5-10% of the
flat rate (Montagnes Magazine (2009)).
The economic costs and benefits of snow making have to be evaluated. Investments may
require between 15-20 years amortize, taking into account at least 100 days per year of
snow-making with temperatures below -3°C.
The production of one m³ artificial snow costs 2.50Euros, including digging and leveling work,
electricity for compressors and canons and compaction (Canardages (2010)).
In the season 2007/2008 the average costs of one m³ of artificial snow amounted to
0.83Euros, while the prize of the water is the least expensive factor regarding the whole
production: 0.05Euros for water, 0.16Euros for servicing, maintenance and insurance cover,
0.11Euros for setting up and displacement of snow canons, 0.14Euros for personnel
expenditures and 0.37Euroscovering electricity costs (SePT/ACPT (2009)).
The total production costs, comprising the amortization of the installations, would be in the
order of 2-2.50 Euros per m³ of snow (Badré, Prime et al., 2009 in SePT/ACPT (2009)).
14
The high costs of snow making constructions are used for the argumentation of producing
artificial snow for whole ski areas. This contradicts the necessity of saving water and energy
(quelle?). Snow-making initially aimed on the compensation for missing snow cover, but has
evolved to a routine procedure of covering entire ski runs before the start of natural snow fall
to ensure snow certainty during the entire season (December to April) (Bürki et al 2008 in De
Jong, C. (2009)).
7. Outlook
The Alps are prone to receiving less snowfall and more rainfall as temperature increase due
to global warming (De Jong, C. (2009) (2)).
Those valleys having balanced winter and summer tourism or four-season tourism from the
beginning are today’s winner of climate change (De Jong, C. (2009)).
The future of European ski resorts is strongly limited by global warming. Even with
sophisticated technological advancements in snow-making, artificial snow will be principally
limited by increasing temperatures within the next 10-30 years. Technical adaptation will also
be limited by natural (water availability), economic (costs of energy and investments), social
(decreasing demand and acceptance) and legal (regulatory) aspects, with negative feed
backs concerning the environment. Intensification of this process is not sustainable. Thus
artificial snow-making can only be considered as a medium-term solution (De Jong, C.
(2009) (2)).
15
REFERENCES
- Newspaper articles -Canardages (2010). Canard enchaine neige de culture. La fausse neige nous prend pour le
flacons. Issue from 2010/01/20.Translated from French.
De Jong, C. (2009). A seasonal solution? Science and Technology, Vol.4, p. 234-235
DIE WOCHENZEITUNG (2011). Dieses Wettrüsten ist ein Irrsinn. Issue of 2011/4/7, Thema
15, Nr.14. Translated from German.
Montagnes Magazine (2009). Actus environnement. Un pôle montagne pour l´Institut
français du tourisme. Issue of 2009/11, P. 83-86. Translated from French.
Opinions (2012). Tribune du Genève. Issue from 2012/01/10, P.4. Translated from French.
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De Jong, C. and Barth, T. (2007). Challenges in Hydrology of Mountain Ski Resorts under
Changing Climate and Human Pressures. ESA, 2nd Space for Hydrology workshop, “Water
Storage and Runoff: Modeling, In-Situ data and Remote Sensing", Geneva (Switzerland), 12-14 November 2007
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pistes with artificial and natural snow, Arctic, Antarctic and Alpine Research, Vol. 36,
No. 4, p. 419-27.
De Jong, C., Masure P., Barth T. (2008). Challenges of alpine catchment management
under changing climatic and anthropogenic pressures. iEMSs 2008, International Congress
on Environmental Modeling and Software
16
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in alpine water resources management – a regional assessment“. Hydrol. Earth Syst.
Sci., 12, 91-100, 2008.
 De Jong, C. (2007). “Artificial snow drains mountain resources”
EnvironmentalResearchWeb, Talking Point Article.
http://environmentalresearchweb.org/cws/article/opinion/30703, August 2007.
 Campion, T. (2002). Impact de la neige de culture. Agence de l’eau Rhône
Méditerranée Corse. Report, pp. 67.
De Jong, C. (2009) (2). Ecological environmental change and winter sports: lessons learned
from the Alps, Prospectives from China. The Mountain Institute. University of Sayon ,France.
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(2008).“Signatures of Evaporation of Artificial Snow in the Alpine Lower Troposphere
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SRef-ID: 1607-7962/gra/EGU2008-A-11002, EGU General Assembly 2008.
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l’environnement. (Artificial snow and its effects on the environment). Annual Report,
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Tourism, Djerba, 9-11 April 2003
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International Forum on Water Policy, Chapter 5, Routledge, pp.288.
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De Jong, C. (2010). La production de neige artificielle. Nature et Patrimoine n 32. Text
translated into English.
Doering, A. et al (1996). Schneekanonen, Aufrüsten gegen die Natur. Für den Arbeitskreis
Alpen des Bundes Naturschutz in Bayern E.V., Bund Naturschutz in Bayern E.V. In:
http://www.slf.ch/ueber/organisation/oekologie/gebirgsoekosysteme/projekte/kuenstliche_sch
needecke/index_DE (27.03.2012)
 Rochlitz, K.-H. (1989). Wenn der Mensch das Wetter macht. Pro und Contra
Schneekanonen. In: Alpin Magazin 3/89. München.
 Wechsler, H.G. (1989). Schneeanlagen - Technik und Umwelt. Referat bei
der Generalversammlung der ANEF 1989 in Montecatinie Terme, Motor im
Schnee, 5.
 Kammer, P. & 0. Hegg (1989). Auswirkungen von Kunstschnee auf
subalpine Rasenvegetation. Verh.Ges.Ökol. 19: 758-767
Rixen, C. et al (2002). Kunstschnee und Umwelt: Die künstliche Schneedecke unter der
Lupe. WSL-Institute of Snow and Avalanche Research SLF
SePT/ACPT (2009). La neige de culture en Savoie et Haute-Savoie. Gestion durable des
territoires de montagne. Direction départementale de l`équipement et de l´agriculture de la
Savoie – SePT/ACPT. Université de Savoie – CNRS – Laboratoire EDYTEM.
 AFSSET (2008). La neige de culture: Évaluation des risques sanitaires lies à
l’utilisation d’adjuvants pour la fabrication de la neige de culture (Artificial
snow: evaluation of sanitary risks associated with the use of additives for the
fabrication of artificial snow), Report by the Afsset. (French Agency for health,
environmental and work security),pp. 104.
 BADRÉ M., PRIME J.-L. et RIBIÈRE G. (2009). Neige de culture : Etat des
lieux et impacts environnementaux, note socio-économique. Conseil Général
de l'Environnement et du Développement Durable, Paris, 162 p.
18
 ODIT France (2008). Les domaines skiables face aux aléas d’enneigement et
le développement de la neige de culture, ODIT France, Paris, 13 p.
Teich, M. et al (2007). “Klimawandel und Wintertourismus: Ökonomische und ökologische
Auswirkungen von Kunstschnee.“ Technischer Beschneiung. Report, Eidg.
Forschungsanstalt für Wald, Schnee und Landschaft WSL, Birmensdorf, pp. 169, 2007.
Wemple, B. (2007). Hydrology and water quality in two mountain basins of the Northeastern
US: assessing baseline conditions and effects of ski area development. In Scientific Briefing.
HYDROLOGICAL PROCESSES Hydrol. Process. 21, 1639–1650 (2007). Published online
24 April 2007 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/hyp.6700

Artificial Snow Production for Winter Sport Recreation and the
Resulting Effects on Water Quality and Macroinvertebrate Community
in Alpine Streams
Willa Capobianco
Taylor Kravits
Jason Scholz-Karabakakis
Francis Oggeri
Andrew Shaw
Executive Summary:
Primary Issue
Ski resorts draw millions of gallons of water from nearby sources and pump it to higher
elevations to be used as snow cover. This high water consumption, coupled with additive factors,
could cause problems to both water source and the receiving mountain stream ecology.
The goal of this paper is to determine risk to of; additives, chemicals, or biological factors have
on stream water quality and macroinvertebrate communities; water withdrawing requirements for
snow production, and its effects; salts applied to designated ski trails.
Purpose Statement
The purpose of this paper is to provide an insight of the effect of ski resorts on water quality and
macroinvertebrate communities through the production of artificial snow, trail “salting” for ski
racing, and water withdrawal from nearby rivers. The objectives of this paper are:
• Determine what types of major snow additives are used in artificial snow production
• Estimate yearly loads of additives on a watershed
• Establish risks associated with chemical groups found in additives and racing salts on stream
water quality and aquatic communities.
• Identify volume of water withdrawn for artificial snow production.
• Formulate recommendations for improving and reducing risk associated with producing and
maintaining artificial snow.
Key Recommendations
Using snow additives does not pose a significant risk, however because available research is
limited, and as a precautionary measure, several steps can be taken to minimize the risk of
uncertainties.
These measures are: limiting additives to those that do not contain trade secret proprietary
formulas, as third party testing is often non-existent or limited, using biological or mineral
compounds that play a natural role in snow/cloud formation so there are fewer uncertainties, and
creating retention/settling pond. Ski resorts should strive for increasing annual efficiency with
regard to water withdrawals.
Introduction:
Problem Statement:
In Vermont, revenue from ski slopes is an important part of the economy that draws in
approximately 19 million dollars every year in the winter (UVM, 1999). Artificial snow is
produced with chemical additives and water is drawn from surface water to create pre-season ski
trails on mountains. The impact of artificial snow is not yet understood. We examined the effects
of producing artificial snow with chemicals, water withdrawal, addition of salts to the slopes,and
what alternatives may exist.
Justification:
The chemical additives found in snowmaking are important problems to look at in relation to
ecological effects including water quality and water uptake from natural sources of water. The
winter sports recreation industry relies heavily on artificial snow production to start the ski season
earlier and to sustain it up to 2-4 weeks longer (Keller et al., 2004; Rixen et al., 2004).
Considering the forecasted predictions based on climate models, it can be conjectured that
increasing global temperatures will lead to an increased dependence on and use of artificial snow
(Rivera et. al, 2004).
The issue of water withdrawal for the use of snowmaking and its effects on macroinvertebrates
becomes another cause for concern. Macroinvertebrate populations can be used as indicators for
overall stream health. The state of Vermont has done testing on local streams of various ski
resorts in order to observe the health of the streams. Ski resorts such as Jay Peak, Smuggler’s
Notch, Bolton Valley, and Stowe have been listed as having adverse effects to aquatic life, biota
and habitat because of the withdrawal of water for snowmaking (VDEC, 2010). Water
withdrawal also decreases flow rate within streams (VDEC, 2010). A greater understanding of
these ecological ramifications is needed. This lends itself to a requisite for researchand increased
ecological design around artificial snow production.
Methods/Approach:
Search engines (Google Scholar) and Internet journal databases (Web of Science) were searched
for articles relating to the production of artificial snow. Resources were evaluated for original
scientific integrity and used to assess the possible risks of snowmaking. Several widely
mentioned compounds (see Table 1) were identified and examined for possible environmental
effects, and specifically, any correlating effect on macroinvertebrates. Due to proprietary
regulations not all chemicals used in additives were disclosed, and some chemicals lacked
adequate research on their potential impacts. In these cases similar compounds were used to
speculate possible impacts on the environment. Numerous resorts in Vermont were contacted
about their water withdrawals, additives used and other snow production factors. These figures
were taken into consideration along with the reviews of available literature. For specific
additives, standard Material Safety Data Sheet (MSDS) forms were consulted to evaluate
potential threats.
Findings:
Many times there was no direct research done between snow additives and macroinvertebrate
communities. Inferences were made between available toxicological data, degradability, and
manufacturers reports.
Artificial Snow Additives Found:
Biological Chemicals Salts
Snowmax Drift Ammonium Nitrate
Ammonium Chloride
Ammonium Sulfate
Potassium Chloride
Sodium Chloride
Table 1: A list ofcommonly used additives for snow production and altering trail conditions.
With the advancement of delivery systems, proprietary formulas have been developed to alter the
conditions needed for the production of artificial snow, based on a survey sent outto local
Vermont ski resorts. Depending on weather conditions, additives can be injected into the water
used in this process. These additives can include gases such as carbon dioxide and liquid nitrogen
(Ritter, 2004). Another additive is silver iodide, an ice nucleation agent that is commonly used in
cloud seeding (Super, 1988). This practice has largely been discontinued, but is used to facilitate
cloud formation and initiate precipitation. Though silver iodide has a high LD50, the MSDS
states that “longterm degradation products may arise.” It goes on to say that “the products of
degradation are more toxic” (MSDS). The potential chronic health effects of exposure to this
compound remain unknown. There were no further studies found on these additives or their
conjunctive use with other ingredients.
Other additives such as kaolinite a mineral used in soaps and detergents. This clay particle
enhances ice crystal formation; it isalsothe main ingredient in porcelain. By itself this product is
not known to be extremely harmful however, “when contaminated with silica it may produce
severe lung effects” (MSDS).
While many of these compounds that are not proprietary and are every day materials, the effect of
essentially atomizing these compounds in low temperatures has not been tested for the formation
of new, unintended secondary compounds. It is possible that using several different additives
could form such compounds. There really has not been much testing on this or the above
mentioned compounds with regard to their use on ski pistes to assess components of ecosystem
health, and nothing specifically on macroinvertebrates. The use of nitrates found in racing salts
and unfiltered stream or lake water sometimes results in a fertilizing effect, increasing biomass on
the mountain and altering species dynamics (Rixenet. al, 2003).
Salts are not used for artificial snowmakingbut are applied toski trails to improve the qualityof
snowfor races.The salt crystals break up into ions;these ions lower the freezingpoint of the
snow, which hardens the surface. This provides a dense layer of snow with a consistent surface.
Chlorides and nitrates are the most common salts used on ski trails. They are added after the snow
has been dispersed on the trails for the purpose of hardening the snow by creating an icy surface
(Rixenet. al,2003). Different salts are used depending on weather and snow conditions because
they vary in their snow melting properties. Among the most common salts are ammonium nitrate,
ammonium chloride, ammonium sulphate, potassium chloride, sodium chloride and phosphates.
Few studies have addressed the ecological effects salts have on ski trails. One study on anOregon
ski trail found that 500,000 kg of salts wereused from May to September to sustain summer
skiing (Rixenet. al,2003). It was found that chloride concentrations of streams within the
drainage of the snow field were 30 mg/L compared to 1–6 mg/L found in a stream outside the
drainage of the snowfield (Rixenet. al,2003). Increasing chloride concentrations can be toxic to
stream life, EPA lists standards for acute and chronic levels at 860mg/L and 230mg/L. Currently,
levels of chloride in some streams adjacent to ski slopes are still well below those levels, however
ski resorts can add more salts to slopes each year to lengthen seasons. Nitrate salts have great
fertilizing properties leading to increases in vegetative biomass in alpine meadows, however
nitrate salts also result in water acidification, eutrophication, and direct toxicity of inorganic
nitrogen compounds (Rixenet. al, 2003). With addition of salts to ski slopes leading to increased
chloride concentrations, acidity, eutrophication, and nitrogen pollution in streams and watersheds,
Europe has set restrictions for salting ski trails and it is now only allowed when necessary
(Teichrob et. al, 2009).
Chloride salts are widely used in road salts and, consequently, stormwater and snowmelt runoff
often contain high concentrations of chloride in areas of application. A study in Colorado
determined that “aquatic insects are very sensitive to high chloride levels” (Bialasieweiz, 1999).
Other studies have been conducted on the effects of road de-icing salts on the environment. These
salts are very similar to the ones used for salting ski trails. Areas impacted by deicing salts have
been observed to have greater influxes in Na, Ca, and Cl in nearby streams with Cl concentrations
remaining elevated throughout the year (Wempleet. al, 2007). In urban areas where road de-icing
occurs chloride concentrations in stream around 3000 mg/l wererecorded, studies show that
increased salt level in the environment can have deleterious on both flora and fauna of aquatic
species (Blasius 2002). Few studies have been published on the environmental impacts of salting
ski trails, with the few that have been both negative and positive environmental impacts have
been documented as mentioned in the above paragraph. The largest concern with the addition of
salts appears to be the increased chloride concentrations of ground and surface water around ski
areas.
More modern snowmaking techniques include the use of bacteria as a method to create snow. An
example of a product is called Snowmax. Snowmax is a trade name for the Pseudomonas
syringae. This bacterium naturally creates a protein that is a catalyst for ice formation. This
effectively raises the temperature at which water will freeze or nucleate. Being non pathogenic
and inactivated, snowmax does not prove to be a substantially harmful product to humans. This
is mainly because the levels of endotoxins in snow are low. (Lagriffoul et.al, 2010).
Ski Area Water usage
millions gal/hr
gal/min Drift
gal/day
Drift
gal/year
(4 months)
Cambridge (Smuggs) 0.33 230 0.62 521.64
Burke 0.09 63.33 0.17 142.8
Dover
(Mt. Snow)
0.06 416,6 1.12 940.8
Fayston
(Mad River)
0.13 90.0 0.22 184.8
Killington 0.82 570.0 1.54 1243.6
Ludlow (Okemo) 0.9 625.0 1.82 1528.8
Stowe 0.67 465.0 1.25 1050.0
Stratton 1.29 846.6 2.42 2032.8
Warren (Sugarbush) 0.32 221.67 0.60 504.0
Average: 739.2
Table 2. Based on 2005 USGS data. Estimated Water Withdrawals and Return Flows in Vermont
in 2005 and 2020
Drift isanother effective additive for producing snow.Organo-silicone surfactant is the common
chemical name for the Drift mixture. Eighty-four percentof this mixture is composed of modified
heptamethyltrisiloxane. The Aquatrols corporation does not disclose the other sixteen percent
because it is listed as a trade secret (Aquatrols, 2009 a ). As the chemicals decrease the cohesive
properties of the water particles,the surface tension also decreases. This results in an increase in
the droplet surface area. When water is pumped out of a snow gun the droplets often collide
before they form snowflakes, creating wet snow (Burke, 2011). Decreasing the cohesion forces
allows the droplets to flatten, increasing the surface area and allowing the droplet to freeze
quicker. Because the chemical properties decrease the number of droplets forming wet snow, the
quality of the snow is more manageable for ski areas (Burke, 2011). Drift is injected into the
water at a ratio of 3:1,000,000 gallons. This means that for every million gallons of water there
are three gallons of drift (Aquatrols, 2009 a). Sugarbush resort used about 221.67 gallons of
water each minute in the 2005. This equals out to be 504 gallons of drift used every year. Table 2
shows the amount of drift that would be required for each ski resort based on the flow rate
(gallons/minute) in 2005. Although some ski resorts are larger they require less uses of drift. This
may be explained by the lower amount of water withdrawal due to the increased efficiency of the
snowmaking equipment.
According to an environmental impact summary the chemicals in Drift have a low impact threat
because they have a low toxicity and an ability to be degraded by soil particles (Borgert, 2002).
Since the chemical suppliers sponsored the tests, theywere not done using high doses that would
emulate the effect of a spill. There is only limited available research on snowmaking additives, so
most of the information was gathered from distributors and speculated from the properties of
related chemical groups. Polydimethlysiloxane chemical groups are similar to the chemicals in
Drift. These groups of chemicals bond to clay particles and can be degraded by microbes
(Borgert, 2002). MSDS suggest that because of the low toxicity and high solubility, the chemicals
do not pose a threat from snow making to macroinvertebrates or humans (Borgert, 2002). The
LC50 (lethal concentration) and EC50 (effective concentration) for Drift both occur at high
concentrations. They range between 100 and 1000 parts per million (Borgert, 2002). This
concentration would occur during a spill. According to the MSDS the direct discharge in
situations such as spills should be avoided however the environmental effects of spills has not
been disclosed or studied (MSDS ). Long term effects are not expected to impact the environment
because of the chemical’s ability to be degraded by the soil. The effects of high concentrations
on ecosystems requiremore research.
Conclusions:
Risks from snow additives are not the only possible threat from artificial snow on streams, butthe
amount of water withdrawn from local streams to produce artificial snow could also pose a
problem for aquatic life in the streams. Water used to generate snow is most often pumped from
surface water sources, mainly lakes and streams (Medalie,2012). From the available withdrawal
data, average Vermont ski resort uses 467,800 gallons of water per day for snowmaking (Table 2)
Sugarbush ski resort uses about 380 million gallons of water a year and has snowmaking
coverage on 70 percent of its trails (Hoffman, 1994). Surface water withdrawals for snowmaking
affect stream health. “Poor water quality and stream health can devastate insect and fish
populations” (Briggs, 2000). This can cause a cascading effects on other organisms that rely on
the insect and fishpopulations in the stream. For examples if fish populations were to decline so
could terrestrial life that depend on the fish as food. Ski resorts however, can use man-made
ponds so they reduce their impact on rivers and surface waters.
Ski resorts that use their own man-made ponds specifically for snowmaking might be considered
a safer alternative when considering the effect on waterways. This was not examined in this
study, since all the resorts assessed withdrew water from naturally occurring lakes or streams.
However, from personal communication with Brian Fitzgerald, Streamflow Protection
Coordinator at the Vermont Agency of Natural Resources, told us that some ski resorts such as
Sugarbush, use periods of high flow in the river to fill up the retention ponds, so that in winter
when flow is low, there is water available that does not need to be withdrawn.
In order to minimize ski resort loss predicted by climate change, snowmaking will most likely
substantially increase over the next 100 years (Scott et. al, 2008). This increase in snowmaking
will lead to a higher withdrawal rate of water unless retention ponds are created to allow melted
snow to be used next season instead of drawing it through mountain tributaries. Snowmaking and
grooming increases the time that snow stays on trail due to increased density, which may cause
hydrologic issues with flow rates(Keller et. al, 2004).
Recommendations
We recommend that ski areastry and move towards sustainable practices in regards to water use,
and in house treatment. This reclaimed wastewater can be used on the mountains for artificial
snow. Swales and other storm water retention is also a good way to reduce the strain on
surrounding water sources.For example, Sugarbush is working on restoration of their nearby
brooks and streams.
Table 3. Taken from Rice Brook restoration website from EPA.org
(http://water.epa.gov/polwaste/nps/success319/vt_rice.cfm)
A restoration project was taken on by Sugarbush ski resort to restore the 1.6 mile long Rice Brook
from an impaired stream to awell functioning class B stream (Table 3). The problems associated
with the stream was a low EPT values, relatively low macroinvertebrate densities, and biotic
communities with high percentages of oligochaetes (indicating poor water quality) (EPA, 2011).
High EPT values indicate that there is a high diversity of pollution-intolerant macroinvertebrates
living in the water. Many of the issues associated with the stream were caused by stormwater
runoff, which can be attributed by excess water from snowmelt caused by artificial snow
production. Sugarbush ski resort remediated the stream by installing 29 swales (ditches on the
sides of roads that collect stormwater) in Summer 2005 (EPA, 2011). Water collected from these
swales istreated before discharge into the Mad River watershed. Yearly monitoring plans have
been established and have shown improvements in the macroinvertebrate habitat. Programs such
as Sustainable Slopes are volunteer groups that monitor the environmental plans created by ski
resorts.
Another recommendation to help mitigate the effects from several aspects ofalpine skiing is the
Sustainable Slopes initiative. Sustainable Slopes is an “Environmental Charter for ski areas” that
includes management principles in several categories such as energy conservation, clean energy,
waste management, fish and wildlife, and wetland and riparian zones. Each of these categories
contains principles for sustainable slope as well as options for fulfilling the principles
(Sustainable Slopes, 2005). Although the sustainable slopes program does not hold or require ski
areas to legally follow or meet all principles, the options it provides on fulfilling the principles
would be beneficial especially in the snow making process. Building retention ponds to capture
snowmelt, reuse of wastewater, and use of soil or other materials to decrease the amount of water
needed to achieve certain terrain (jumps and half pipes) are just a few of the options (Sustainable
Slopes, 2005).
Restoration efforts and monitoring programs are only the first steps towards creating sustainable
ski slopes. Additives such as Drift and Snowmax are going to be used by ski resorts, especially
since an increase in climate change will make artificial snow more of a necessity by ski resorts.
From this assessment it has been determined the additives will not pose as a significant threat as
long as they are used at the recommended concentration. There is always a risk of large scale
spills, but we conclude it as a low risk. However, summer skiing should be limited, due to the
large amount of salts that are added to ski resorts, whichcan negatively affect water quality.
Acknowledgements:
Thank you to Philip Halteman and Dr. William Bowden for their assistance in completing this
project.
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Journal of Alpine Research | Revue de
géographie alpine
99-4 | 2011
Mélanges 2011
Environmental risks and impacts of mountain
reservoirs for artificial snow production in a
context of climate change
André Evette, Laurent Peyras, Hugues François et Stéphanie Gaucherand
Édition électronique
URL : http://rga.revues.org/1481
DOI : 10.4000/rga.1481
ISSN : 1760-7426
Éditeur
Association pour la diffusion de la
recherche alpine
Référence électronique
André Evette, Laurent Peyras, Hugues François et Stéphanie Gaucherand, « Environmental risks and
impacts of mountain reservoirs for artificial snow production in a context of climate change », Revue
de Géographie Alpine | Journal of Alpine Research[En ligne], 99-4 | 2011, mis en ligne le 07 octobre 2011,
consulté le 30 septembre 2016. URL : http://rga.revues.org/1481 ; DOI : 10.4000/rga.1481
Ce document a été généré automatiquement le 30 septembre 2016.
La Revue de Géographie Alpineest mise à disposition selon les termes de la licence Creative Commons
Attribution - Pas d'Utilisation Commerciale - Pas de Modification 4.0 International.
Environmental risks and impacts of
mountain reservoirs for artificial snow
production in a context of climate
change
André Evette, Laurent Peyras, Hugues François et Stéphanie Gaucherand
1 Mountain reservoirs are hydraulic structures built in mountain leisure resorts, used to
store water mainly for the production of artificial snow. Their implantation in mountains
with altitudes of between 1,200 and 3,000 metres means undoubtedly that they are highly
specific reservoirs compared with reservoirs located in plains. This is because their
position results in specific difficulties, given the complex geological and geotechnical
contexts (slope, diversity of substrates, etc.), specific mountain hazards (avalanches,
debris flows, etc.), and intense solicitations due to the snow and cold. From an ecological
viewpoint, these reservoirs are built in environments that are very rich, but also very
fragile. Given their dominant position above facilities with very high traffic and steep
slopes of versants that are likely to create torrential flows in the event of a break,
mountain reservoirs have relatively high risks in spite of the low volumes of water stored.
2 The number of mountain reservoirs in France has grown sharply since the beginning of
the 2000s. In 2008, there were some 105 structures with a capacity of over 10,000 m³. In
the next 10 to 20 years, a significant increase in the number of mountain reservoirs is
expected and the observed trend is a marked increase in the size of structures, which has
risen from an average capacity of 40,000 m³ to 100,000 m³ today on new projects (Peyras
et al., 2009).
3 Other countries of the Alpine chain such as Switzerland, Austria and Italy are facing
similar problems concerning the risks and impacts of mountain reservoirs (Ancey C,
2009). However, it must be noted that very few studies have been conducted on the issues
raised by mountain reservoirs and that there are practically no scientific or technical
publications available on the subject in France or abroad.
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1
4 Following various technical and ecological questions raised about mountain reservoirs by
public authorities and professional mountain organisations in France, Cemagref has
launched a research and development project aimed at building upon feedback from
these structures in the various fields concerned and at laying down down technical
recommendations on technical engineering and environmental protection. This research
and development project called Baraltisur (safety of mountain dams) was conducted over
two years between 2007 and 2008. It was financed bythe Ministry of Ecology under the
“Risque Décision Territoire” (hazards, decision-making, territory - RDT) research
programme, by the Interministerial Delegation for Planning and Territorial
Competitiveness and the Provence-Alpes Côtes d’Azur (PACA) region. It was conducted by
a multidisciplinary project team made up of engineers and researchers from Cemagref,
EDF and the engineering firm ISL. It was concluded with the publication of
recommendation guidelines on the siting, design, construction and management of
mountain reservoirs (Peyras et al., 2009).
5 In 2007, in-depth, documentary and on-site surveys were conducted on mountain
reservoirs in the Alps and the Pyrenees (Evette et al., 2009). The structures studied were
subjected to several investigations : analysis of structure project design studies
(environmental impacts, risks for public safety, hydrology, mountain hazards, technical
documents, etc.), in-depth inspections and occasional thorough assessments. A total of
about 65 structures were thus examined, enabling the team to gather substantial
information about the design, state, behaviour, incidents, operating and monitoring of
mountain reservoirs. The survey also covered the factoring of environmental impacts in
the data and impact studies established during the mountain reservoir design phase.
These impacts were also observed on-site during field investigations.
6 This article aims at drawing up a detailed inventory of the risks and impacts on the
environment related to mountain reservoirs in France, so as to establish a complete
panorama in this area. It begins by putting mountain reservoirs into societal, social and
environmental perspective : It establishes the historic and current framework of the
economic development of mountain resorts and studies the influence of climate change
on snow conditions. Next, the article develops the risks and impacts of mountain
reservoirs. It provides a technical presentation ofmountain reservoirs in France, analyses
the various risks and specific hazards faced by these structures and describes the various
environmental impacts linked to the construction and management of mountain
reservoirs.
Snow cover : a central issue for the development of ski
resorts
7 The rapid growth of ski resorts in France is part of the land-use planning rationale that
promotes the spread of a resort model called the third-generation model according to the
typology established by Cumin (1970). The representation of successive generations of ski
resorts, is in itself, a testimony of the normative approach promoted by government
services, mainly CIATM and SEATM
1
. What is generally called the “Snow Plan” has no real
existence in the traditional sense of planning, but rather refers to an effort by public
authorities to fit out new mountain sites based on a veritable doctrine of land-use
planning (Knafou, 1978 ; François, 2007).
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8 The dynamic of mountain tourist development was and mainly continues to be the
subject of strong tensions and the issue of snow cover is going to play an increasingly
dominant role in discussions on the issue. This is because the effectiveness of the
granting of public loans in ski resorts on virgin sites was a key factor in justifying a policy
that was controversial, as seen by the local conflicts arising from expropriations
(including the one that pitched a section of the population of Hauteville-Gondon and
Société des Montagnes de l’Arc, during the buildingof the Les Arcs ski resort) and in the
development of national-scale environmental criticism (specifically the “La Vanoise
affair” that broke out when the Val Thorens resort was created). As a corollary to the
assertion of the superiority of third-generation ski resorts, the appearance of alternative
mountain tourism development modes has aroused significant criticism. The “snowless”
winters of the 1989/1990 and 1990/1991 skiing seasons played a central role and
highlighted the general limitations of winter sports resorts as solutions for land-use
planning.
9 In the context of climate change, the OECD report (2007) raised the alarm by
differentiating between sites where future snow cover appears unlikely to significantly
decrease and those that are directly threatened, depending on their altitude. Moreover,
snow-deficient winters have contributed to raising the awareness of the general public,
who represent potential tourists, to the issue of the opening of ski areas, which is a
crucial factor for drawing tourists to ski resorts. There are therefore two different
strategies : that of high-altitude resorts that focus mainly on downhill skiing and develop
by providing technical solutions to snow-deficiency, and that of mid-altitude resorts that
are mainly oriented towards the diversification of the tourist offering (successive policies
where the resorts enter into contracts at regional level (with the Rhône-Alpes Region
through the Diversified Development Contract in Isère or the Tourism Plan for the Savoie
region). Although the implementation of the “Nivalliance” insurance system set up by the
French national union of ski lift operators (SNTF) has developed a degree of solidarity
between resorts, it has also acknowledged the gap between the modes of development of
ski resorts.
10 There is indeed a huge difference between the different types of resorts, if only with
respect to their ability to generate profit simply from ski lift operations that they can
reinvest, in particular in equipment for producing artificial snow. Bolstered by the
technical rationality that drove their design, mountain resorts have an attitude that some
environmental groups describe as the “race for white gold”. The increase in investments
for the production of artificial snow has contributed to rekindling the debate about the
environmental impact of ski resorts. Against a backdrop where the general public is
highly aware of sustainable development (see the Ski resort Eco-guide, the Sustainable
Development Charter of mountain resorts and the “war of words” – cultured snow vs.
artificial snow, “snow-makers” vs.snow cannons, as well as the highlighting of the
natural components of “production” snow, air and water, vs.the possibility of using
additives such as Snomax – which pits operators against environmentalists), the
supervision of practices to guarantee the opening of the ski area has become a crucial
factor.
11 The practice of the use of water resources is particularly incriminated in line with the
criticisms against urbanisation and the concentratedtourist flows. Drawing directly from
water courses can thus give a negative image of theresort’s activity. It also raises the
question of availability during low-water periods and reinforces constraints related to the
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3
legal obligation to protect reserved torrent flows.The margins for manoeuvre presented
by the use of drinking water can also have a negative impact for the image of resorts
given the rareness of the resource. In particular, this solution turns out to be rather
paradoxical as it opens a ski area (with increased snow production), the operation of
which depends on the tourist accommodation capacity(with an attendant increase in
drinking water consumption). To justify these practices, operators argue the
implementation of a controlled management that “stores water when it is abundant and
restores it when it is scarce” (ANEM, 2007), stressing the “unsuspected talents of artificial
snow”
2
. This rationale deals with only part of the reality of the impact of mountain
reservoirs and their widespread use.
Increasingly unreliable snow cover due to climate
change
12 Snow cover conditions in mountain resorts are increasingly unreliable because of climate
change. For example, some authors predict that in a warmer climate, the snowline, as
well as the line of natural snow reliability, will rise by 150 metres per 1°C warming (IPCC,
2007 ; OECD, 2007).
13 A team of Swiss researchers has studied the probableimpact of an average warming of 4°
C on snow cover. This warming of 4°C is more in theupper range of the predictions for
2100 of the models presented by the GIEC (IPCC, 2007). This Swiss study concludes that
this warming would decrease the volume of snow in the Alps by 90 % at 1,000 metres, by
50 % at 2,000 metres and by 35 % at 3,000 metres. Moreover, snow cover duration would
be greatly reduced, ending 50 to 60 days earlier at high altitude (above 2,000/2,500
metres) and 100 to 130 days earlier at average altitudes close to 1,000 metres (Beniston et
al., 2003).
14 Lastly, with respect to skiing activity, an OECD study predicts that a 2°C increase in
temperature would bring the number of naturally snow-reliable ski areas to around only
80 % of the current total ski areas in the Savoie, Hautes Alpes and Alpes de Haute
Provence departments, where the highest ski resorts are located. However, if the
temperature were to rise by 4°C, this percentage would drop to 71 % in Savoie, 33 % in the
Hautes Alpes and 10 % in the Alpes de Haute Provence (OECD, 2007).
15 The probable reduction of periods of snow cover as a result of climate change, their heavy
impact on skiing and on the increased production of artificial snow are issues that are
also raised in other parts of the world such as theUnited States (Scott et al., 2006) and
Australia (Good, 1995).
The mountain reservoir population in France and their
main technical characteristics
16 In 2008, there were some 105 mountain reservoir structures in France, of over 10,000 m3
in the Alps (85%) and Pyrenees (15%), knowing that the other French mountain ranges
(Jura, Vosges and Massif Central) have about a dozen mountain reservoirs. This area is
constantly growing, and in 2008, there were about 30 mountain reservoirs being built or
being assessed by public authorities (Peyras et al., 2009).
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17 Nearly all mountain reservoirs are embankment dams, which have specific technical
characteristics. The two main ones are presented below. First of all, given the
topographical conditions of the mountain, they are located on shelf areas, and often do
not contain a thalweg. They are therefore usually designed according to cut-and fill
techniques, like a basin, partially surrounded withan embankment.
Figure 1 : Principle of the cut-and-fill design of a mountain reservoir with the entire basin sealed by
a geomembrane
18 The geology of mountain sites creates natural sealing tightness issues: talus on slopes,
moraines, fissured rock, cargneules, karsts, absence of clay at high altitude, etc. Hydro-geological analyses of foundations often show water inflows (70%). They are therefore
often artificially sealed by laying geomembranes onthe entire basin surface (85 %).
19 A large proportion of these dams (65%) have averageembankment heights of between 5
to 10 metres above natural land, while 20% of mountain reservoirs are very small dams
less than 5 metres high. It must be noted, however, that 15 % of these structures are
embankments more than 10 metres high.
20 Embankments are built with the deposits of material available and excavated on the
construction site. They mainly comprise moraines andschists (60 %). There are also, to a
lesser extent, embankments made from silt and rock-fill mainly from quartzite, gneiss
and limestone.
21 The average volume of water stored is approximately40,000 m
3
. However, today, there is
a sharp increase in volume for structures under construction or for which applications
are being processed, with an average volume of approximately 100,000 m
3
.
22 With respect to their administrative situation (decree on hydraulic safety of 11 December
2007), mountain reservoirs are evenly divided between categories D and C, with a
minority (10%) in category B. Future reservoirs that are being built should significantly
change this breakdown.
23 50% of these water reservoirs are built at an altitude between 1,500 and 2,000 metres, 30%
under 1,500 metres and 20% above 2,000 metres. Future projects show a sharp decrease in
mid-altitude reservoirs at below 1,500 metres.
Structures subject to potentially high mountain-specific hazards and public safety risks
24 In addition to the usual hazards encountered in lowland areas (floods, earthquakes),
mountain reservoirs may be exposed to hazards that are specific to mountain areas:
avalanches, rapid flows and geological hazards – slope slip-offs, cavings, falling blocks.
The intensity of most of these mountain hazards is very difficult to quantify during rare
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5
to exceptional return periods, which makes it even more difficult to design mountain
reservoir protection structures when they become necessary.
25 The breakdown of the exposure to avalanches, torrential and geological hazards is as
follows:
• about 20 % of mountain reservoirs are built on proven avalanche-prone sites. Half ofthem
are subject to very high hazards. For some of these reservoirs, structures to protect against
these hazards (deflecting and retarding structures, etc.) have been provided and they
generally take routine events to events with moderately significant impacts into account.
Figure 2 – Mountain reservoir impacted by an avalanche
Image2
(credit: Cemagref)
• one out of two mountain reservoirs is subject to debris flow and about one out of three is
exposed to a major hazard.
Figure 3 – Mountain reservoir exposed to a proven debris flow hazard
(credit: Cemagref)
• one quarter of mountain reservoirs are exposed to moderate to major geological hazards,
broken down by order of frequency into risks of falling blocks, underground instability,
mass cavings and landslides.
26 Should the mountain reservoir be impacted by one ofthese phenomena, the volume of
water stored in the reservoir may be expelled very quickly and cause a flood wave that
may spread downstream. On the whole, the survey showed that one out two mountain
reservoirs « affect public safety” in the sense that a break of the embankment part of the
structure or any sudden expulsion of stored water would have significant adverse effects
on downstream population and properties. There are several reasons for this (Peyras et al.
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, 2009) : (i) their towering position above highly touristic facilities or ski resort residential
areas ; (ii) steep slopes and hillside geological conditions that would lead to rapid flows
(bed-load or debris flow) in the event of a release of substantial flows that could
significantly increase the destructiveness of the accident ; (iii) short distance between the
reservoir and downstream challenges, and extremely reduced time interval for the
arrival of a break wave.
Figure 4 – Mountain reservoir overlooking challenges
(credit: F. Dinger, Cemagref)
Impacts of mountain reservoirs on the environment
27 The siting and management of mountain reservoirs have an impact on Alpine and sub-Alpine land and aquatic environments. These environments have a very high biodiversity.
For example, in a 100 km long square, the Alps harbour between 2,000 and 3,000 vascular
plant species (ferns, conifers and flowering plants) (Aeschimann et al., 2004). These
environments are particularly fragile because of their extremely slow growth dynamics.
Therefore any damage to them will require longer recovery times than at lower altitudes
and the natural reconstruction dynamics may last for several decades. Furthermore,
mountain species already undergo pressure related to climate change. For example, a
study conducted on 171 forest species showed that there was an upward shift in plant
species by about 30 metres each decade (Lenoir et al., 2008).
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Impacts on surface runoffs
28 Artificial snow requires 3,000-4,000 cubic metres ofwater per hectare of slope, and snow-covered surfaces are on the rise (Marnezy, 2008). In 2008, 23 % of ski slopes were using
artificial snow, drawing an estimated annual volumeof 15 million cubic metres of water
from the environment (Paccard 2010). The figure was 70 % in Italy, 59 % in Austria and
23 % in Switzerland (Paccard 2010). In winter there is already great pressure on water
resources due to the demand in drinking water (De Jong et al., 2008). The traditional
operation of mountain reservoirs usually consists in creating a water reserve in summer
and autumn, during a period where the adverse impact of the water used on aquatic
environments is lowest. However, some mountain reservoirs are filled continually in
winter or are filled several times during the season. In these situations, the quantitative
impacts on torrents and surface runoffs may be substantial. This is because the greatest
impacts correspond to the water collected during the winter period of minimum flow,
during which significant collection may freeze small outlets and reduce the survival
abilities of fish fauna (pollution dilution, compensation water). In a study presented in
2002 by the Rhone-Mediterranean and Corsica water agency, it was estimated that 61 % of
water collected for artificial snow accounted for less than 10 % of minimum annual flow
while 31 % collected between 10 and 50 % of minimumannual flow (Dugleux, 2002).
Impacts on humid zones and peat bogs
29 Mountain reservoirs are sometimes built directly onhumid zones. According to a survey
conducted by Cemagref, an estimated one-third of these structures are established on
humid zones. Furthermore, during the construction phase, the circulation of machines
and the storage of materials also have potential impacts on these environments. Over and
above the direct impacts on these environments that are part of the national heritage,
mountain reservoirs can also act indirectly. Peat bogs and humid zones are under the
natural control of the quality as well as the quantity of water supply. The drop in
groundwater basins is thus likely to result in drying, while earthworks upstream of these
zones create fines and clog up humid zones. There is also a possible risk from fertilisers
and composts used when banks or slopes are replanted upstream. These may alter the
physical and chemical qualities of the waters that cross humid mountain zones that are
usually oligotrophic.
Environmental risks and impacts of mountain reservoirs for artificial snow pr...
Journal of Alpine Research | Revue de géographie alpine, 99-4 | 2011
8
Figure 5 – Mountain reservoir partly built on a humid zone
(credit: Cemagref)
Impacts on groundwater
30 Mountain water reserves are low and usually restricted to fractured rocks (De Jong et al.,
2008). Furthermore, the extreme general permeability of mountain soils and the gradual
nature of snow-melt runoff make aquifers and therefore drinking water catchment
relatively vulnerable. The water that supplies the mountain reservoirs is derived from
surface waters and therefore more mineralised than meteoric waters. These waters may
sometimes be contaminated by pollutants from human activities (water treatment,
breeding, etc.) (Dinger et al., 1995 ; Wipf et al., 2005). The French agency for environmental
and occupational health safety (AFSSET) concluded in a study (AFSSET, 2008) that
pollution of drinking water storage sources by artificial snow made with water of bad
microbiological quality was a risk that could not be ignored.
Impacts on land environments
31 Aside from the direct impacts of mountain reservoirs during their construction or during
related works, these structures also have an indirect impact on land environments with
respect to the spreading of artificial snow. This isbecause, as mentioned above, the water
used for artificial snow is generally richer than meteoric water and therefore provides
the environment with nutrients, which may be present in sufficient quantities to alter the
composition of vegetation in the areas concerned inthe medium term. To illustrate this
assertion, a study by a team of Swiss scientists has shown changes to the number and
types of plant species of plant communities, an increase nitrophilous species and snow-Environmental risks and impacts of mountain reservoirs for artificial snow pr...
Journal of Alpine Research | Revue de géographie alpine, 99-4 | 2011
9
bed species and a reduction in true grasses (Wipf et al., 2005). This same study showed
that plant diversity was lower on groomed slopes than in neighbouring meadows. It has
also been sometimes observed that there is a pollution by hydrocarbon from the snow
cannons themselves, mainly from “high pressure” ones (Dinger et al., 1995). “If we
consider that the quantity of snow produced corresponds to 300 litres of water per square
metre and per season, corresponding to nearly one metre of snow, then 0.1 g of
hydrocarbon is deposited per square metre of slope at the same time as the snow”. This
hydrocarbon pollution, when present, is in additionto the pollution by grading machines.
Impacts to the landscape
32 Landscape impact can be significant because of earthworks and structures that may mar
the appearance of mountain slopes. However, these impacts may be reduced, in particular
when mountain reservoirs are positioned on flat sites, (as long as they are not occupied
by humid areas), when they are given the same shape as that of natural lakes and when
the slopes are replanted (Peyras et al., 2009).
Impacts on human activities
33 There may also be impacts on pastoral and leisure activities, in particular during the
construction phase because of restricted access or the dust generated.
Conclusion
34 This article presents the environmental risks and impacts linked to the building of
mountain reservoirs as well as the management issues raised by these structures. It
highlights the original and current social context of the development of mountain leisure
activities. It also provides several avenues to explore on the possible consequences of
mountain climate warming (probable decrease in snowcover periods with a significant
impact on skiing activity and an increase in artificial snow production).
35 Mountain reservoirs are small-sized dams (65 % of mountain reservoirs have a height of
between 5 to 10 metres) that store limited volumes ofwater (average volume of 40,000 m
3
). Despite their small size, the feedback from the survey conducted on mountain
reservoirs in France has shown that one out of two mountain reservoirs »affects public
safety” in the sense that a break of the structure or the sudden expulsion of stored water
would have serious consequences for downstream population and properties. This is
because of their dominant position above facilitiesand the steep slopes of versants that
would lead to rapid flows. Mountain reservoirs are also liable to be impacted by
mountain-specific hazards such as avalanches, geological hazards and rapid flow hazards.
Feedback shows that nearly one out of two mountain reservoirs is exposed to at least one
mountain hazard. In the event of an impact by one of the above phenomena there could
be a very rapid expulsion of the volume of water stored in the mountain reservoir.
36 Mountain ecological environments are rich, but alsofragile because of their very slow
recovery dynamics. Mountain reservoirs have significant impacts on these environments,
not only during their construction, but also when they are operated. For example,
feedback showed that during the construction phase, one third of these structures had
Environmental risks and impacts of mountain reservoirs for artificial snow pr...
Journal of Alpine Research | Revue de géographie alpine, 99-4 | 2011
10
been built on humid zones or in other environments of high ecological importance with
impacts on protected species (animal or plant). In addition to these direct impacts,
indirect impacts linked to the suspension of sediments or hydrological alterations have
also been observed. During the operating phase, potential impacts mainly concern water
courses when water is collected during minimum annual flows or during the emptying of
unusable water into the environment.
37 There are solutions for keeping environmental impacts and risks to a minimum. These
are described in the book Mountain Reservoirs (Peyras et al., 2009). This reference guide has
established best practices concerning the technological risks. In particular, to limit
natural risks, it is important to choose sites with very low hazard levels. To keep
environmental impacts to a minimum, the preliminarychoice of the mountain reservoir
site is also essential : siting principles are described in Mountain Reservoirs. It must be
based on an in-depth comparative analysis of the different potential sites, taking all
potential impacts into account, whether on land or aquatic environments, landscape or
occupied by humans. Lastly, it is important that potential project owners consult and
involve the various stakeholders, mountain professionals, qualified design firms and
public authorities, right from the preliminary study phase and in the choice of site.
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NOTES
1.Following the experiment in Courchevel to which it significantly contributed,the findings of
the Chambery unit of the Public Works administration were supervised, from 1964, by the
Interministerial Commission for Mountain Tourism Development (CIATM) and became its
technical department.This unit was then institutionnalised by the creation, in 1971 of the
Mountain Tourism Design and Development department (SEATM, tody the DEATM, which is a
division under the Atout France economic interest grouping)
2.See the SNTF campaign:http://www.lamontagneenmouvement.com

Спаси Витоша

събота, 17 март 2018 г.

негативното влияние на изкуствения сняг върху алпийските курорти

Floristic changes in subalpine grasslands after 22 years of artificial snowing

Abstract

Impact of artificial snow and ski-slope grooming on snowpack properties and soil thermal regime in a sub-alpine ski area

Does artificial snow production affect soil and vegetation of ski pistes? A review

Abstract

Long-term impacts of ski piste management on alpine vegetation and soils

Summary

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Спаси Витоша

събота, 17 март 2018 г.

негативното влияние на изкуствения сняг върху алпийските курорти

Floristic changes in subalpine grasslands after 22 years of artificial snowing

Abstract

Impact of artificial snow and ski-slope grooming on snowpack properties and soil thermal regime in a sub-alpine ski area

Does artificial snow production affect soil and vegetation of ski pistes? A review

Abstract

Long-term impacts of ski piste management on alpine vegetation and soils

Summary

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