Drafts in the Plate
PARANA AND RIO DE LA PLATA ARRIVAL/SAILING DRAFTS
DEPTH: Means the distance between the water surface and the river bed/bottom given at a certain point i.e. alongside the berth, in the port access channel, in the main channel, at the critical passes along the main waterway, etc. This value is given basis a conventional ZERO level. To establish the prevailing depth at the time you have to consider the reported river height/level at the concerned point plus the given datum depth. Therefore when in our reports we include the daily river levels it is to help you understand the actual depth/draft variations according to the daily fluctuations of the river level.
The river level fluctuations depend primarily on the natural flowing volume (running volume of water) of the river which depends on the rains regime and the opening or closing of locks at the existing water dams in the upper reaches of the Parana, namely Itaipu and Yacireta (Paraguay and Brazil) and secondly from the existing tides in the River Plate basin which affect the river level up to San Lorenzo and Rosario. This does not mean that the Parana is tidal, only that the tides in The River Plate may affect the river level.
Is the max vessel´s draft allowed basis the existing least depth in the concerned port/berth or channel
The max daily sailing draft from the Parana ports is established considering the leastdepth in the access channel to the concerned port or in the critical point of the main waterway according to the concerned port location minus 60 cms UKC. (under the keel clearance).
Basis foregoing and as a practical example for San Lorenzo/Rosario allowed sailing drafts pls note:
Provided today´s report from the Waterway Authorities reads that the least depth in the main channel (depth at zero datum plus prevailing river level at the point) is situated at Km 358 (Yaguaron pass) between Villa Constitucion and San Nicolas and reads 10,98 mtrs the MAX AUTHORIZED SAILING DRAFT for the day from all ports north of KM 358 is 10,98 minus 0,60 mtrs UKC i.e. 10,38 mts FW except from those ports/terminals where the restriction is in the access channel or eventually alongside the berth itself
THE RIVER PLATE
The River Plate is the natural access to the Parana system.
When we talk about the River Plate in connection with the Parana sailing drafts it is automatically understood that to suggest max sailing drafts from the upriver ports we take into consideration that the vessel has to transit the River Plate channel to and from Recalada. In this context the River Plate is referred to as the stretch between pilot station Recalada and the end of the Mitre Channel in upstream direction and which comprises about 190 nautical miles.
The dredged guaranteed DEPTH in the River Plate channels as contractually maintained by the concessionaires Hidrovia and for which they charge the known Toll is 34 FT referred to zero datum height. The River Plate is tidal and the average tide range (difference between low and high tide) is about 1 mtr in average but it can be highly influenced by the wind direction. North to west winds decrease tabulated values and South/southeast winds increase them
Likewise in the Parana, transiting the River Plate Channels requires as per regulation a 2 feet UKC at all times and therefore deep drafted vessel (especially those drawing 34 ft (10,36 m) or slightly more) have to await adequate tides at the existing waiting points to reach Recalada.