COMPONENT PARTS OF A GARDEN 179 



the water line, and an outlet i ft. from the bottom 

 of the basin is recommended, as this gives a cross 

 flow of water. (See Diagram 73.) The outflow 





DIAGRAM 73. 



must not be absolutely at the bottom or it will 

 become blocked by sediment, and in any case 

 the mouths of all pipes should be protected by 

 fine wire caps. 



The highest point in the bend of the outflow 

 pipe controls the level, 

 and where the ground 

 line is the same as the 

 water, it is impossible to 

 conceal a bend. (See 

 Diagram 74.) An outflow 

 at the desired water level 

 must be substituted, 

 bending at once through 

 the thickness of the sides so as to clear the ground 

 beyond ; or it may be a vertical one inside the 

 basin itself. (See Diagram 74.) 



The overflow water may be led into the ordinary 

 drainage system, or it may pass into bog beds, 



DIAGRAM 74. 



