18 LANDSCAPE GAKDENING 



fore the landscape-architect can begin his main 

 design he must have a clear mental survey of the 

 land with which he has to deal, and upon this he 

 bases the large elements of his scheme ; for thereby 

 are determined the locations of such features as 

 house, drives, gardens, and water. Furthermore, 

 he readjusts the contours in an esthetic way, in 

 order to obtain an even balance in cut and fill 

 wherever possible. 



In the laying out of roads, the natural profile of 

 the road must so agree with the contour that the 

 percentage of grade will not change too rapidly, 

 and that later, when the engineering plan is 

 worked out, too extensive cuts and fills will not 

 appear, destroying the natural aspect of the sur- 

 face. 



In the erection of retaining walls there must 

 first be a raison d'etre, as well as justification from 

 the engineering point of view, preventing too 

 steep grades and terraces. Walls of other types 

 are considered architecturally. 



In the question of engineering drainage, the 

 landscape-designer is concerned with the combina- 

 tion of surface and subsurface drainage. Sur- 

 face drainage takes care of the water that is likely 

 to destroy the best appearance of lawns and plant- 



