Diploma Thesis Defense by Mr Marios Stergiou
Thesis Title «Simulation of the underground flow at the region of Timpaki Crete, using the FEFLOW model»
Tuesday May 22 2021, at: 14:00, Venue: : Link Zoom Meeting
https://tuc-gr.zoom.us/j/82295600247?pwd=TTAyK2hNZlVxai96TkhUa3VlYUZKdz09
Meeting ID: 822 9560 0247
Password: 602495
Examination Committee
- Professor George Karatzas (advisor)
- Professor Nikolaos Nikolaidis
- Dr Ioannis Trihakis
Abstract
In the present bachelor thesis, the simulation of the groundwater flow will be examined using the simulation model finite element FEFLOW. The simulation performed for the area of Tympaki and more specifically for the Messara valley. Messara is located in the south part of Heraklion, constitutes the largest plain area of Crete where the vast percentage of fruits and vegetables of the island is produced. Based on the above, this area shows great demands of water supply, fulfilled mainly via pumping from aquifers.
To provide an accurate simulation of the groundwaters, data processing was necessary prior to the utilisation of FEFLOW. The data processing conducted using some other software with the most important being the ArcGIS and Microsoft excel where the bulk processing occurred. ArcGIS was used mainly for the processing of the maps. Moreover, it was implemented to insert data on the FEFLOW under tables format. Microsoft Excel used for processing of observation and simulation data exported from FEFLOW. The results and the data were obtained in a table format and for that reason, the chosen software was the Microsoft Excel. On FEFLOW, 5 observation wells were imported with observed values from 2004 to 2020. These wells constitute wells of IGME (Institute of Geology & Mineral Exploration). Afterwards, the values of hydraulic conductivity were imported for each of the geological formations together with the exact altitude of the area. Moreover, the values of the rainfall obtained from the meteorological stations of the area and the pumping wells were imported too. Following that, the boundary conditions on the perimeter of the area were placed. The boundary conditions were of two kinds, those of steady hydraulic head and those of the supply. From the total of four boundary conditions, three of them concerned the supply conditions while the fourth one concerned the condition of the steady hydraulic head. The two main supply conditions for the inflow of the aquifer were placed the first on the north part where the water coming from Psiloritis mountain inflows and the second one on the south part where the river Geropotamos is located. The third one, concerning the outflow of the aquifer was placed on the east side while the boundary condition of the steady hydraulic head was placed on the shoreline where the emptying of the aquifer to the sea takes place.
Once all the data were in place, the five change of pumping scenarios through the wells of the area were examined. Each scenario, dedicated to the reduction of the pumping level by 10% from the previous one. More specifically, the first scenario referred to a 10% pumping reduction, the second to a 20%, the third to a 30%, the fourth to a 40% and finally the fifth to a 50% reduction. The simulation of the above scenarios was also performed using the FEFLOW software. The only variable between the five scenarios was the level of pumping. Those five cases were chosen to demonstrate the amount of increase of the hydraulic head of the aquifer in the case of pumping reduction as a new dam (Faneromeni dam) has been constructed in this area which can provide water to cover part of the irrigation demands of the study area.
