Thesis supervisor: Zsolt Kozma
Location of studies (in Hungarian): BME Vízi Közmű és Környezetmérnöki Tanszék Abbreviation of location of studies: BMEVK
Description of the research topic:
The evaluation of vertical groundwater fluxes is an essential part of both quantitative-qualitative assessment of subsurface water resources as well as any water related environmental analysis. The simulation of groundwater movement (and the optionally coupled transport modelling) requires the spatio-temporal variation of recharge and evapotranspiration as upper boundary conditions. A widespread method to generate this input data is the determination of groundwater flux-depth curves (also called groundwater recharge-discharge curves). These empirical relationships provide the long term average vertical water flux (both recharga and evapotranspiration) as a function of the groundwater water position.
Despite their usefulness and importance, flux-depth curves in general are rather poorly researched and quantified. It is not clear, how the timestep, the time period and the spatial scale affects the shape of the recharge curves. Measurement based verification is generally missing. The actualisation of the recharge-discharge curves poses another challenge as the underlying databases (i) often represent outdated meteorological, hydrological and land use-land cover (LULC) conditions, or (ii) the spatial resolution of the databases improved significantly in the recent past.
The aim of the PhD-study is (i) the derivation of groundwater flux-depth curves, which represent current and proposed future environmental conditions, then (ii) the estimation of vertical groundwater fluxes for Hungary by using relevant water table maps. The reliability and sensitivity of the calculations should also be analyzed as part of the research.
The groundwater flux-depth curves represent the local environmental conditions (climate, LULC, soil). As there are numerous combinations of these defining environmental factors, the number of related recharge curves is also large (the order of magnitude is 100 to 1000 depending on the level of simplification/classification). The applied methodology should be able to handle this challenge, therefore it is based on the algorithm-driven one-dimensional simulation of the unsaturated soil-vegetation-atmosphere (SVAT) system. Input data sources are national databases for climate (e.g Carpatclim, ForeSee), terrain (e.g OVF - Hydrodem), soil hydrological properties (e.g MARTHA, EuroSoilHydroGrid, DoSoReMi) and LULC (e.g CLC 2018, NÖSZTÉP vegetation map). Input data preprocessing and postprocessing of the simulation results is done with GIS tools. Model setup, simulation runs and the export and statistical analysis of the results is carried out with the framework software developed at our department. The verification of the 1D SVAT simulations can be done directly (the comparison of measured and simulated soil water contents) and indirectly (by using the water table timeseries of the national groundwater monitoring network).
Expected outcomes of the research:
• The improved methodology of groundwater flux-depth curve calculation
• Spatial database of the updated groundwater flux-depth curves
• groundwater recharge-discharge maps of Hungary for arbitrary groundwater depth distribution
Number of students who can be accepted: 1
Deadline for application: 2024-05-31
2024. IV. 17. ODT ülés Az ODT következő ülésére 2024. június 14-én, pénteken 10.00 órakor kerül sor a Semmelweis Egyetem Szenátusi termében (Bp. Üllői út 26. I. emelet).
Login
