Passage: Elevation of the Pantanal ranges from 80 to 150 m (260 to 490 ft) above sea level. Annual rainfall over the flood basin is between 1,000 and 1,500 mm (39 and 59 in), with most rainfall occurring between November and March. In the Paraguay River portion of the Pantanal, water levels rise between two meters to five meters seasonally; water fluctuations in other parts of the Pantanal are less than this. Flood waters tend to flow slowly (2 to 10 cm (0.79 to 3.94 in) per second) due to the low gradients and high resistance offered by the dense vegetation.

Question: Where does the most fluctuation in water levels occur?
Paraguay River portion of the Pantanal