## Layers of the model

The model was divided into three horizontal layers. The top layer simulates the quaternary sediments consisting of gravel, sandy gravel, and concrete constructions. The middle layer was created in order to model the underflow of the concrete constructions in the water-bearing gravel and in the thick Neogene series of pervious strata below. The bottom layer consists of Neogene sediments which are, according to geophysical measurements, hydraulically active up to 48 m below the terrain. Each layer is composed of triangular elements that match the shape of building constructions, horizontal geological boundaries, and hydrogeologic inhomogeneities. All three layers are divided into numbered homogeneous zones with respect to the coefficient of hydraulic conductivity. There are 29 homogeneous zones in the top layer. Highly permeable quaternary gravel is found in zones 14, 15, 27, 28, and 29 with the coefficient k=2.1×10-3m s-1. Less permeable terrace gravel (k=5×10-4 m s-1) occupies zones 9-13 and 22-25. Zone no. 1 is the remainder of the water-bearing, higher terrace gravel that has a different coefficient value, k=4.1×10-4m s-1. Zones 2-5 and 16-21 represent the sandy and loamy water-bearing diluvium of the Neogene sediments. Their coefficient of hydraulic conductivity is k=6.4×10-6 m s-1. The last three zones represent parts of buildings in which some parts of their construction are below the groundwater level. Their permeability was set to k=1×10-15 m s-1. In the four construction stages, other zones have been added with the same permeability value (all data above and below are for the current state). The number of zones in the middle layer reaches 23. Very permeable quaternary gravel composes zones 38, 39, 51, and 52 (k=5×10-4 m s-1). The Neogene sediments with the coefficient k=6.4×10-6 m s-1 occupy zones 30-32 and 40-44. Zones 33 and 34 (k=1×10-15 m s-1) correspond to the only two buildings that reach this middle layer. In the bottom layer there are only eight zones. In zone 53 the Neogene sediments have a permeability value of k=1.3×10-5 m s-1; in the remaining zones 54-60, the Neogene sediments have a value of k=6.4×10-6 m s-1. There are no building parts that penetrate this layer in the current state. All coefficients of hydraulic conductivity in all layers and zones were determined using a hydrogeologic survey. The vertical coefficients of hydraulic conductivity were assumed as kz=0.1kx, analogous to other similar problems.