{"id":2151,"date":"2026-09-10T09:15:42","date_gmt":"2026-09-10T09:15:42","guid":{"rendered":"https:\/\/hydroalpslab.ch\/?post_type=projets&p=2151"},"modified":"2026-09-10T09:15:43","modified_gmt":"2026-09-10T09:15:43","slug":"optimising-water-management-for-the-lienne-raspille-project-in-the-face-of-climate-change","status":"publish","type":"projets","link":"https:\/\/hydroalpslab.ch\/en\/projets\/optimiser-la-gestion-de-leau-du-projet-lienne-raspille-face-au-changement-climatique\/","title":{"rendered":"Optimising water management for the Lienne-Raspille project in the face of climate change"},"content":{"rendered":"

Line Moret\u2019s Master\u2019s thesis<\/strong><\/p>\n\n\n\n

In the Alpine regions, climate change is profoundly altering the availability of water resources. The problem is not only the quantity of water available over the course of a year, but also its distribution over time: snowmelt contributes significantly in spring, whilst demand \u2013 particularly for irrigation \u2013 increases in the latter part of summer during periods of drought.<\/p>\n\n\n\n

The project Lienne-Raspille<\/strong>, situated in central Valais, aims to address this issue by capturing some of the water available during the snowmelt period and storing it in the Zeuzier dam. This water can then be released when natural flows are no longer sufficient to meet the region\u2019s needs, whilst also being harnessed to generate electricity via several hydroelectric power stations.<\/p>\n\n\n\n

Line Moret-Crittin\u2019s Master\u2019s thesis sought to anticipate the challenges that the operator may face and to identify strategies for optimising the management of this resource in the long term.<\/p>\n\n\n\n

One resource, many uses<\/h3>\n\n\n\n

One of the distinctive features of Lienne-Raspille lies in the wide range of uses and stakeholders involved. The resource must simultaneously meet the needs for drinking water, irrigation, protection of natural environments, tourism and hydroelectric power generation<\/strong>.<\/p>\n\n\n\n

The project therefore constitutes a genuine integrated water management system, in which decisions must be made on how to store, transfer and allocate the resource in accordance with priorities that are sometimes competing. The region also has a complex governance structure, involving numerous local authorities, hydroelectric companies and other stakeholders.<\/p>\n\n\n\n

The development itself is substantial: in particular, it provides for 12 water intakes, three hydroelectric power stations comprising five generating units, one pumped-storage power station, five control structures and approximately 24 km of pressurised pipelines<\/strong>.<\/p>\n\n\n\n

Simulating the future of urban planning<\/h3>\n\n\n\n

In order to analyse the behaviour of this complex system, Line developed a numerical model of the layout using the software GoldSim<\/strong>. This takes into account water inflows, consumption by various users, storage, pumping, hydroelectric power generation and economic considerations.<\/p>\n\n\n\n

The model was then tested against various hydrological and climatic scenarios, in particular based on projections Hydro-CH2018<\/strong>, in order to examine how the operation of Lienne-Raspille might evolve between now and the end of the century. Stochastic simulations were also used to take account of the interannual variability of resources.<\/p>\n\n\n\n

This approach is particularly important in a region where the gradual retreat of glaciers is set to profoundly alter the hydrological regime. The scenarios examined suggest, in particular, that the Plaine Morte glacier could disappear completely within the project\u2019s lifetime, significantly altering the seasonal distribution of water inflows.<\/p>\n\n\n\n

Anticipating the effects of climate change<\/h3>\n\n\n\n

The simulations show that, under current conditions and for the hydrological variability studied, the projected storage capacity is sufficient to meet demand. However, they also highlight a high degree of sensitivity to hydrological conditions: energy yields and volumes abstracted can vary by approximately \u00b120 % from year to year, whilst the volumes of water not utilised at the intakes show even greater variations.<\/p>\n\n\n\n

In the longer term, the most extreme climate scenarios suggest that new challenges could arise by 2085<\/strong>, despite the construction of the Lienne-Raspille project. The project therefore provides a significant response to climate change, but its operation cannot be based on management rules that remain fixed for several decades.<\/p>\n\n\n\n

More flexible management makes it possible to make better use of water<\/h3>\n\n\n\n

A number of operational strategies have been tested with a view to improving the use of the resource: changes to storage guidelines, a reduction in spillage, adjustments to pumping operations, better distribution of water amongst the various hydroelectric cascades, and taking electricity market prices into account.<\/p>\n\n\n\n

The aim was to make better use of the available water whilst maintaining the volumes supplied to users and ensuring sufficient storage capacity at the end of the snowmelt period.<\/p>\n\n\n\n

For the baseline scenario, the changes tested result in reduce the volume of water discharged by 5.6 %<\/strong>, to increase by 5.3 1Q-3Q volumes withdrawn<\/strong> and, above all, to increase by approximately 30 % net energy-related profit<\/strong>, without affecting the volume of water supplied to users.<\/p>\n\n\n\n

These results show that the value of such a development depends not only on its infrastructure, but also on the quality of its management.<\/p>\n\n\n\n

Integrating water management, weather forecasting and the electricity market<\/h3>\n\n\n\n

The study also highlights several avenues for more dynamic future management. Drought forecasts and meteorological data could enable storage and withdrawal guidelines to be adjusted with greater precision.<\/p>\n\n\n\n

Similarly, hydroelectric generation could be better synchronised with electricity market prices. Hourly fluctuations can be significant: during the September drawdown period, for example, the study found that average prices varied by approximately 5.6 to 12.4 ct\/kWh depending on the time of day<\/strong>. Buffer tanks therefore offer the possibility of shifting part of the production to the most favourable times.<\/p>\n\n\n\n

Other options identified include self-consumption of the energy generated, the use of mini-turbines on certain regulation structures, and the recovery of hydropower that is currently lost during reservoir drawdown at Plans-Mayens, estimated in the model at approximately 450 MWh<\/strong>.<\/p>\n\n\n\n

Towards adaptive management of the regional \u00abwater tower\u00bb<\/h3>\n\n\n\n

Ultimately, this study shows that the success of the Lienne-Raspille project will depend not only on the ability to store more water, but also on the implementation of a proactive, flexible and scalable management<\/strong> of the resource.<\/p>\n\n\n\n

Operating rules will need to be adaptable to changes in the climate, the needs of different users and the electricity market. The model developed therefore provides an initial tool for anticipating these changes and helping to prepare for the future operation of the Lienne-Raspille project.<\/p>\n\n\n\n

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