Zsóka Szabó, Tibor Ridavits , Endre Csiszár, Judit Mádl SzÅ‘nyi
József and Erzsébet Tóth Endowed Hydrogeology Chair, Department of Geology, Eötvös Loránd University, Budapest
(a) Purpose or objectives and status of study or research hypothesis
The aim of the research is to offer a simple and cost-effective solution to the water management problems of the Danube-Tisza Interfluve, Hungary. A field experiment was set up to led rainwater from the roof of a family house to the dug well in the yard. The effects on water levels and quality is continuously monitored for a one-year period. The results can help to understand shallow subsurface processes, provide background for numerical simulations and contribute to the design of settlement and region level recharge systems.
(b) Key issue(s) or problem(s) addressed
In the Danube-Tisza Interfluve groundwater levels have declined significantly in the last decades, due to climate change and other artificial effects. In the past, several replenishment plans have been made, involving large, cross-regional technical investments, but haven’t been implemented due to the lack of adequate financial resources and environmental concerns. The aim of our research is to prove that local scale solutions, which have several environmental and economic benefits, could contribute to easing the water shortage of the area.
(c) Methodology or approach used
Three approaches were used: field experiment, time series analyses and transient numerical simulations to understand on-site processes. The implementation started with cleaning the dug well and the gutters, and they were connected by PVC hoses. Furthermore two observation wells were established, where water level, temperature and electrical conductivity were measured every half hour. Precipitation was measured on a daily basis. Water samples were taken from the dug well for laboratory measurements. Geomathematical methods have been used to analyze time-series data and assess the effects of recharged water. Moreover a transient MODFLOW model was built, to evaluate the effect of the infiltrated roof water on the groundwater level, and to separate the effect of the infiltrating rainwater from the surface and the infiltrated roof water to the dug well.
(d) Results and conclusions derived from the project
The preliminary results are very encouraging. In the first two month the water level increased by 9 cm in the dug well, 20 and 17 cm in the observation wells. The water quality has improved significantly, the TDS, Cl-, SO42- and NO3- content decreased remarkably. Groundwater temperature decreased due to lower winter/spring air temperature. As a result of the modelling, the effect of natural infiltration was found to be higher, however it is overestimated by neglecting the unsaturated zone and the processes therein, and thus further research is needed in this aspect.
(e) Implications of the project relevant to selected conference theme, theory and/or practice
Rooftop Rainwater Harvesting and Managed Aquifer Recharge can be effective tools for climate change adaptation and increasing groundwater resilience.
This research is part of a project that has received funding from the European Union's Horizon
2020 research and innovation programme under grant agreement No 810980.