Oil Embankments. 



ject to temporary and extraordinary swells, occasioned by 

 violent winds, great falls of rain, or the melting of snow ; 

 consequently, they often spread beyond their usual limits, 

 overflowing and injuring the neighbouring land. The ef- 

 fects are so injurious, as to make it an object of importance 

 to prevent or lessen them, by enlarging, and where the 

 level will admit it, deepening and widening the outlet, 

 that the water may at all times ha\ r e a more free and easy 

 discharge. In some cases, the lake has been surrounded by 

 an embankment, extending not only along its sides, but 

 along those of the streams that flow from it, and that by 

 which it is discharged, as far as the level requires; nay, it 

 must sometimes be carried to the higher ground on both 

 sides, to prevent the flood from having any access to the 

 flat land liable to be overflowed. This however, is a very 

 operose and expensive undertaking, and can only be effected, 

 where a drain from the embanked ground, will fall into a 

 river below the lake; otherwise the ground that has been 

 embanked, would be filled with water. 



3. Protection against Rivers. There are two modes by 

 which this can be effected : 1. Deepening the channel; and, 

 2. Raising embankments to protect the flat ground in their 

 neighbourhood. 



1. Where the course of a river is in a straight line, or 

 nearly so, it hardly ever makes any encroachment on its 

 banks, unless perhaps in very large rivers, when they rise 

 nbove their usual level, either by an increase in their own 

 waters, or their flow being in some degree interrupted by 

 the tides. Hence, whenever a river is narrow in its channel, 

 and winds considerably, any mischief which it commonly oc- 

 casions, may be prevented, by deepening and straightening 

 the course of the stream. In one instance, where this im- 

 provement has been effected, it has produced the following 

 important advantages. The waters, which in their crooked 

 course, were formerly almost stagnated, now run at the or- 

 dinary rate of the declivity given them. They never over- 

 flow their banks. Cattle can now pasture upon those grounds 

 in which they would formerly have been swamped. The 

 surface of the water being now, in general four, and some- 

 times six feet, below that of the adjacent fields, this cut serves 

 as a general drain to the whole valley ; so that three hundred 

 acres of meadow, may be converted into arable land ; sixty 

 acres of moss, may be improved into meadow; and five hun- 

 dred acres of arable land, are rendered of double their for- 

 mer value ( 475 ). 



