Fig. 1.
Location map of the study area.
Fig. 2.
Cross-section illustrating a scheme of hydrogeological conditions in the area of Lake Płotki.
Fig. 3.
Groundwater levels in piezometer no. II/401/1 (PIG-PIB 2024).
Fig. 4.
Gradient metre readings: A – under downwelling; B – under upwelling.
Fig. 5.
Spatial distribution of VHGs in the Lake Płotki shoreline zone: A – in November 2022; B – in May 2023. Isobaths according to Jańczak (1996). VHGs, vertical hydraulic gradients.
Table 1.
Results of gradientmetric measurements along the shoreline of Lake Płotki in autumn 2022 and spring 2023. MP, Measuring point; VHG, vertical hydraulic gradient.
| 09-11-2022 | 19-05-2023 | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| MP | L | HGw | HL | VHG | MP | L | HGw | HL | VHG | MP | L | HGw | HL | VHG |
| [m] | [mm] | [–] | [m] | [mm] | [–] | [m] | [mm] | [–] | ||||||
| P01 | 0.49 | 63 | 60 | 0.015 | P16 | 0.45 | 79 | 85 | –0.030 | P30 | 0.40 | 60 | 52 | 0.040 |
| P02 | 0.15 | 49 | 47 | 0.010 | P17 | 0.58 | 89 | 89 | 0.000 | P31 | 0.49 | 85 | 76 | 0.045 |
| P03 | 0.23 | 65 | 60 | 0.025 | P18 | 0.48 | 86 | 90 | –0.020 | P32 | 0.44 | 83 | 66 | 0.085 |
| P04 | 0.53 | 47 | 39 | 0.040 | P19 | 0.44 | 96 | 106 | –0.050 | P33 | 0.43 | 90 | 85 | 0.025 |
| P05 | 0.34 | 69 | 60 | 0.045 | P20 | 0.53 | 35 | 42 | –0.035 | P34 | 0.55 | 41 | 40 | 0.005 |
| P06 | 0.46 | 55 | 52 | 0.015 | P21 | 0.23 | 61 | 66 | –0.025 | P35 | 0.29 | 31 | 35 | –0.020 |
| P07 | 0.36 | 80 | 78 | 0.008 | P22 | 0.34 | 65 | 68 | –0.015 | P36 | 0.72 | 50 | 59 | –0.045 |
| P08 | 0.49 | 92 | 93 | –0.005 | P23 | 0.33 | 27 | 35 | –0.040 | P37 | 0.38 | 73 | 75 | –0.010 |
| P09 | 0.34 | 99 | 95 | 0.020 | P24 | 0.94 | 70 | 80 | –0.050 | P38 | 0.26 | 56 | 64 | –0.040 |
| P10 | 0.48 | 75 | 79 | –0.023 | P25 | 0.47 | 50 | 47 | 0.015 | P39 | 0.25 | 60 | 59 | 0.005 |
| P11 | 0.51 | 95 | 92 | 0.015 | P26 | 0.39 | 55 | 55 | 0.000 | P40 | 0.38 | 85 | 84 | 0.005 |
| P12 | 0.21 | 39 | 40 | –0.005 | P27 | 0.35 | 104 | 100 | 0.020 | P41 | 0.27 | 84 | 82 | 0.010 |
| P13 | 0.18 | 66 | 69 | –0.015 | P28 | 0.35 | 78 | 69 | 0.045 | P42 | 0.35 | 76 | 71 | 0.025 |
| P14 | 0.40 | 98 | 98 | 0.000 | P29 | 0.41 | 65 | 62 | 0.015 | |||||
| P15 | 0.51 | 90 | 92 | –0.010 | ||||||||||
Table 2.
Statistical characteristics of the vertical hydraulic gradient (VHG) measurements.
| Hyporheic exchange | N | VHG [–] | ||||||
|---|---|---|---|---|---|---|---|---|
| [-] | [%] | MIN | AV | MD | MAX | SD | V | |
| 09-11-2022 | ||||||||
| Upwelling | 13 | 44.8 | 0.008 | 0.022 | 0.015 | 0.045 | 0.012 | 55.8% |
| Neutral | 3 | 10.8 | ||||||
| Downwelling | 13 | 44.8 | –0.050 | –0.025 | –0.023 | –0.005 | 0.015 | –59.6% |
| 19-05-2023 | ||||||||
| Upwelling | 9 | 69.2 | 0.005 | 0.027 | 0.025 | 0.085 | 0.025 | 91.7% |
| Neutral | 0 | 0 | ||||||
| Downwelling | 4 | 30.8 | –0.045 | –0.029 | –0.030 | –0.010 | 0.014 | –49.8% |
Fig. 6.
Conceptual model of the hyporheic zone functioning in the shoreline of Lake Płotki.