Groundwater Sustainability
CLÉMENT ROQUES
Monitoring alpine ecosystems to better understand and predict their evolution
The Lasset catchment (Réserve du Saint-Barthélemy, Pyrenees, France)
The Lasset catchment is located in a low-mountain range environment, with a mid-continental to Mediterranean climate. It is a unique observatory gathering critical knowledge on emblematic alpine wetland ecosystems. It specifically seeks to better understand the critical physical, chemical and biological processes involved by cross-referencing high frequency data on biotic and abiotic compartments. The observatory also aims at providing managers and stakeholders with tools and methodologies for monitoring and predicting the future evolution of alpine wetlands. The Lasset catchment is equipped with a network of 2 discharge stations, 1 weather station, 4 piezometers and 5 temperature sensors deployed in springs and wetlands.
Map (a) and pictures (b) of springs, streams and wetlands in the Lasset catchment. The map differentiates perennial (in blue) from intermittent (in red) systems. In picture 1 is shown the major peatland of the catchment taken from a major groundwater seepage zone that regulates the diversity of observed ecosystems. The Lasset stream during baseflow regime is pictured in 2, with a discharge rate of about 50L/s. In picture 3 is a perennial bedrock-fed spring. Photos: Clément Roques. On the right are the data gathered by the stream monitoring station with water level, water temperature and electrical conductivity.
The Alp-Canfinal catchment (Poschiavo, Alps, Switzerland)
The Alp-Canfinal catchment is located in the Bernina range in Canton Grisons, south-east Switzerland. It shows typical erosion from glaciations and gravitational slope deformation. The highest peak is Piz Canfinal at 2812m a.s.l. The catchment recharge is typical of temperate climate and high alpine environments, dominated by snowmelt regimes. The catchment is equipped with 1 discharge station, 3 deep boreholes and 4 weather stations are located nearby.
On the right, map and pictures of springs, streams and wetlands in the Alp Canfinal catchment. The map differentiates perennial (in blue) from intermittent (in red) systems. In picture 1 is shown the upper part of the catchment in winter 2021, where the borehole KB4 is located. The Val d'Ursé stream during baseflow regime is pictured in 2. Picture 3 shows the sampling of a perennial bedrock-fed spring in summer. Photos: Clément Roques.
The Alp-Canfinal catchment has a unique network of three deep boreholes (200 meters deep) revealing key information on groundwater dynamics
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The boreholes are part of a monitoring network that comprises a total of 19 boreholes drilled in the context of the Lago Bianco pump storage. They are equipped with pressure and temperature sensors deployed at two different depth. Bellow is a timeseries of hydraulic head measured at depth 125 and 145m in the borehole KB4. The timeseries shows high pressure amplitudes, with about 40m head change from baseflow to snowmelt peaks. We use this data to calibrate hydrological models designed to explore future evolution in the context of climate changes.
