274 



ration of its bed by alluvion, and it becomes indisppfc- 

 sibly necessary to remove it, for fear of worse conse- 

 quences. This being thrown upon the dykes, helps to 

 increase their extension and elevation, and also to in- 

 crease the quantity of made ground. 



Thus, as these operations are continued and re- 

 peated, the alluvion is found to accumulate in an in- 

 creased ratio, and the bed of the river becomes ele- 

 vated again, even above or higher than where the river 

 formerly united with the bay, and there is no descent 

 to carry off the water. The consequence is, that if 

 the obstruction be not seasonably removed, and there 

 occurs an unusual high tide, the waters or current of 

 the river, defying opposition, makes a breach or more, 

 through the dykes, and forms lateral canals or courses 

 into the gulf. The earth or alluvion thus accumu- 

 lated, either directly or indirectly, is conveyed still 

 further into the gulf, and it becomes necessary to clear 

 out the bed of the river, repair the breaches, and fill 

 up -the new canals, in order to confine the river to its 

 original bed, and secure the advantage of its naviga- 

 tion. 



Another consequence attending the division of the 

 waters of a river by a breach, or irruption through its 

 banks or dykes, is, that when the breach is repaired 

 and filled up, at one or both extremities, the ground 

 being on a descent from the river, or lower at a little 

 distance than at its margin, small laguues or lakes are 

 formed. 



