256 IRRIGATION. 



sea-side plants. Generally there is an abundance of fresh 

 water available for the improvement of the marsh, but 

 in the effort to keep the salt water out this is kept in, 

 with the result of perpetuating the marsh, notwithstand- 

 ing its drainage. The remedy is by flooding the land 

 systematically and as copiously as possible with this fresh 

 water, and then withdrawing it ; repeating the process 

 until the salt has been dissolved and carried off. 



The remedy can be applied in two ways, at least. The 

 one is, in case a stream of water passes through or by the 

 marsh, when the fresh water is diverted by a dam in the 

 stream and a canal or ditch, upon the salt land, where 

 it is retained for a time and then discharged through the 

 gate at low tide. Another is, by closing the gates and 

 securing them so as to retain all the drainage water until 

 the ground is deeply covered, when the gates are opened 

 and the water discharged. The repetition of this pro- 

 cess will, in time, remove the salt from the soil and leave 

 it ready for the plow, and the profitable cultivation of 

 crops. To carry out these operations effectively, it is 

 only necessary to apply to practice any of the methods, 

 found to be most advisable, that are explained and de- 

 scribed in the preceding chapters of this book. It is 

 difficult to imagine a case, in which it would be impossible 

 to apply some of the plans herein described for the 

 drainage and irrigation of meadows. 



The Improvement of River Flats, that are partially 01 

 periodically submerged, is another of the direct opera- 

 tions of irrigation. The object of this improvement is, 

 to reclaim low lying banks of gravel, sand, or mud, eithei 

 upon the sides of tidal estuaries, or upon streams thai 

 have changed their course, and have left these ruined 

 spots to mark the ravages made by former freshets. This 

 process of reclamation consists in forming banks or 

 courses of piles and brush, by which the tidal flow or the 

 high water of rivers at certain seasons, when a large quan- 



