The project MontanAqua studies integrated water management in a region of the Swiss Alps facing climate uncertainty. Preliminary results show the region has abundant water resources currently, but water demand may exceed supply by 2050. The Tseuzier storage lake plays a key role in managing water for multiple users, but its concession expires in 2037 requiring negotiation between stakeholders. The project explores scenarios for sustainable regional water management in the future as the system shifts from supply-focused to demand-based approaches.

1. Gestion durable de l’eau
Programme nationale de recherche PNR61
Emmanuel REYNARD
Institute of Geography, University of Lausanne
Integrated water management at the
regional scale in a context of climate
uncertainty. The project MontanAqua
Projektteam:
WP1: Karl Herweg, Martin Hölzle, Matthias Huss, Martina Kauzlaric, Hanspeter Liniger, Emmanuel
Rey, Bruno Schädler (Uni Bern, Uni Fribourg)
WP2: Mariano Bonrisposi, Emmanuel Reynard (Uni Lausanne)
WP3: Olivier Graefe, Christine Homewood (Uni Fribourg)
SP: Stephan Rist, Flurina Schneider (Uni Bern)

2. The Alps = Water tower of Europe
Viviroli & Weingartner (2004), in Hydrology and Earth System Sciences

3. Dry areas in the Alps
Mean summer precipitations © Swiss Hydrological Atlas

4. The project MontanAqua (2010-2013)
Synthesis package
WP 2
WP 1 WP 3
climate (change)
socio-
water availability different
water resources economic and
in space and time users
political system

5. The project MontanAqua (2010-2013)

6. The study area
 South-facing slopes in the Valais
 500 m to 3000 m asl.
11 municipalities, 36‘500 inhabitants
760‘000 tourist nights per year

8. Pictures: E. Rey, 2011

9. Tseuzier dam and artificial lake
Picture: E. Reynard, 2010 Capacity: 51 million cubic meters

10. High demographic dynamic
Bonriposi 2011

11. Conceptualisation of the water system
Catchments (headwaters)
Water availability
today, 2050
Water consumption
Icogne Montana Randogne Mollens today, 2050
Water management
Lens Chermignon
today, 2050
Venthône Miège
Clusters of communes
St- Veyras Sierre
Léonard

12. Conceptualisation of the water system
Schneider, 2012

13. Preliminary results: the Plaine Morte glacier
Plaine Morte glacier
(2800 m asl.)
Montana
(1500 m asl.) Sierre
(500 m asl.)
© Schweizer Flugwaffe
Role of the glacier in a region approaching water stress?
“Additional
” water to
the region?
Runoff (mio m3/yr)
VS
BE
Runoff from
Plaine-Morte region
Huess, 2012

14. Preliminary results: karstic system
EO - Eosin
UR -Uranin Simme - Lenk
Tzeusier lake - Loquesse
Contribution: some mio. m3/yr,
cf. water consumption approx. 10 mio. m3/yr
UNIBE

15. Preliminary results: hydrology
1. Annual precipitation is 3 to 4
times higher than at Montana
station
2. Significant contribution of glacial
melt-water (until  2060)
3. Tseuzier storage lake: key
element for the management of
the (abundant) water
Water tower of the
MontanAqua region!
Contribution: some mio. m3/yr
(cf. water consumption 10 mio m3/yr)
UNIBE

16. Preliminary results: water uses
2010
Agricultural water need [m3]
P [cm]
Temp
[°C]
Water need for
irrigation Artificial snow
1 mio m3
use [m3]
Water
Drinking water
P [mm] from March to October
 Drinking water is partly used for irrigation
 Irrigation: no data available  Water need was modelled (however,
calculated volume is smaller than the effective water volume transported in
the bisses)
 No common view at the regional scale and difficulty to obtain some data
Bonriposi, 2012

17. Preliminary results: hydropower production
Wi Su In the future:
A Filling of Tseuzier lake
(Potential) competition between Potential for a multi
A purpose storage
different users particularly in time
of shortage
B B Hydro power production
has priority. Other water users have
to pay the market price for
electricity
when using water from the lake
Bonriposi, 2012

18. Preliminary results: socio-political system
- Hypothesis 1 ( past, today): The institutional and political
fragmentation has not been a problem because of the almost
unlimited availability of water (TRUE)
- Hypothesis 2 ( future): The system is changing from supply-
oriented management to demand management and from a
fragmented system to an integrated management system
(partly TRUE)
- The Tseuzier lake, the useful storage capacity of which exceeds
the present day water use by 5 times, offers as multi purpose
storage an interesting opportunity for the water management in
the future.
Homewood, 2012

19. Scenarios for the future (2050)
catchments
Water availability
today, 2050
Emission scenario
A1B
- different realisations
Water consumption
Icogne Montana Randogne Mollens today, 2050
Water management
Lens Chermignon
today, 2050
Venthône Miège
3 Visions (scenarios)
- expansion
Veyras Sierre - optimisation
- Moderate development
by Group RegiEau

20. Outlook
Tseuzier storage lake is situated in
the middle of the water tower;
concession until 2037
Key element to satisfy all needs:
• From single to multi purpose storage
• How?
• Process of negotiation between different stakeholders: water
users, communes, power company
• Management / priorities in times of shortages
Interesting case study for a quite frequent situation in the future (cf. also new
lakes)