Snow resources and the early prediction of hydrological drought in mountainous streams

Code:	SREP-DROUGHT
Department's Principal Investigator:	doc. Ing. Martin Šanda, Ph.D.
Co-operation:	Swiss Federal Institute for Forest, Snow, and Ladscape Research, Birmensdorf, Switzerland M. Nodia Institute of Geophysics, Tbilisi, Georgia
Start:	2014-09-01
End:	2017-08-31
Research focus:	A Tri-National research effort will evaluate how summer low flows and droughts are affected by winter snowpack in three catchments Alpbach (Prealps, central Switzerland), Kamenice (Jizera Mountains, northern Czech Republic), and Gudjaretis-Tskali (Little Caucasus, central Georgia). Two GIS-based rainfall-runoff models will simulate more than 10 years of runoff in streams by means of measured rain- and snowfall, and other meteorological variables. The models use information on the geographical settings of the catchments and knowledge of the hydrological processes that transform rainfall into streamflow, in particular between spring snowmelt and summer droughts. Thesy include snow accumulation and melt, evapotranspiration, subsurface storage from spring recharge until the summer outflow, and will be studied by means of environmental isotopes 18O and 2H. The knowledge about the isotopic composition of the different water sources will allow to identify the flowpaths and estimate the residence time of snow meltwater in the subsurface and its contribution to the stream. The application of the models in different nested or neighbouring catchments will explore their potential for further development and allow for a better early prediction of low-flow periods in various mountainous zones across Europe.

Research team members at the departement:

The first achievements show a substantial potential of the data sets of the three catchments for application of different methods. Isotope data of Georgia and Czech Republic reveal that the catchments show significant differences in isotopic composition of water types contributing to streamflow. This will allow for the quantification of the runoff components and therefore for a better parameterization of the rainfall-runoff models.

Considering the snow water resources, the first approach was applied to represent low flows within the study catchments in Switzerland only considering SWE. Additional information about isotopic composition and residence times of the runoff components will give further knowledge about all water sources contributing to low-flow discharge.

Synchronizing the sampling methodology and collection and pre-processing of spatial and temporal datasets with respect to different background conditions in the project countries will substantially enhance the experiencewith the application of the models and improve their performance in different geographical settings.