The Paraná River rises in Brazil and in terms of length and outflow rate (which varies between 11600 and 17700 cbm/sec on average at Rosario, km420) it is the 2nd most important river in the southern hemisphere.
Its course flows mainly from N to S except between Posadas, km 1584, and its confluence with the Paraguay River, km 1245, where its direction is E-W. A dominant characteristic is its left margin is higher than its right margin.
High and low water levels are experienced in a periodical manner, the former usually during March to May and the latter between August and October. Its behavior is irregular and as sudden falls can be experienced care must be taken as to calculation of draft and cargo intakes.
River levels, influenced by many factors as: rainfalls, behavior of other tributaries, prevailing winds at the River Plate, tidal waves; and forecasts should be checked every day at points where the vessel is to navigate.
The Paraná River is considered to have 4 sections:
1- The lower Paraná from the Delta to Puerto Gaboto (Km 482), which is considered to be tidal as far north as Rosario. The daily effect of the tide is experienced at Campana (km 97) and Zárate (km 110) about four hours after Buenos Aires and about half strength. The effect diminishes and is only very slightly felt at San Pedro (km 276) and beyond Ramallo it is negligible except in times of a very low river. San Lorenzo and Puerto Gral San Martín. San Martín. San Martín is also within the Lower Paraná, the main route downriver having been dredged to permit within certain limitations a navigable draft of 10.36 m (34ft).
2- Middle Paraná: Santa Fe and Diamante are situated on this stretch of the river and the main channel route downriver to San Martín has been dredged to permit, within certain limitations, a navigable draft of 6,70 m (22 ft).
3/4- Upper and High Paraná and River Paraguay. Trade beyond Santa Fe is, due to the reduced depth, usually by barge or feeder vessels although small ocean going vessels occasionally call at Asunción. Drafts of the barges are usually around 3/ 3,60 m (10/12 ft) but at times of very low river may be limited to around 2,80 m (9 ft) or less.
It should be noted that waiting or anchoring zones, apart from port roads, are found at:
Km 238/248 and 230/232 of the Lower Paraná.
Km 172/174 of the Paraná Guazú.
Km 59/ 62- 67,3- 69,5- 80- 108- 111- 120- 123- 149,5 and 153 of the Paraná de Las Palmas.