NAVIGATION WORKS 253 



tide to the next, sometimes for several days. The 

 tide, which is sHght at Montevideo, is greater at the 

 bottom of the harbour on the Barra del Indio, some- 

 times rising nearly forty inches there. From there it 

 advances with difhculty northward, over the Ortiz 

 Bank, along the Uruguayan shore, whereas it passes 

 freely into the deeper zone on the Argentine side.^ 

 At Buenos Aires it still has a depth of thirty inches. 

 From there it advances northward by the Martin 

 Garcia channels beyond the Playa Honda. The channel 

 of the Pozos del Barca Grande, which crosses the 

 Playa Honda bank from north to south, parallel to 

 the edge of the delta, is oriented in conformity with 

 the tidal currents and maintained by them. It is not 

 attached to the river, and it is separated from the 

 mouths of the Parana de las Palmas or the Parana 

 Mini by shallows which are navigable only to small 

 boats. The Rias of the Uruguay, where the tide 

 raises the water twelve inches, forms a sort of reservoir 

 which, at the ebb, feeds a strong current round Martin 

 Garcia and sweeps the channels there. 



The work done for the improvement of the estuary 

 includes the deepening to thirty feet of the Barra del 

 Indio and the dredging of a straight channel from 

 that point to Buenos Aires. Steamers of large ton- 

 nage going up the Parana leave this channel twenty- 

 six miles east of Buenos Aires, and turn north in 

 order to pass east of Martin Garcia, and enter the 

 river by the Parana Guazu or the Parana Bravo. 

 Since 1901 the Argentine Government has considered 

 a plan of opening a direct route from Buenos Aires 

 to the Parana de las Palmas, either by cutting an 

 artificial canal at the foot of the cliffs, across the 

 Tigre archipelago, or by using the channel of the 

 Pozos del Barca Grande and cutting the narrow bar 

 which closes the Parana de las Palmas below. If 



' The current at high tide is stronger than at low tide, and it has 

 shifted to the north-east the streams which find an outlet on this side. 



