Engineering in landscape problems concerns the lay of the land, the alteration of grades, the construction of topographical work, drainage, and the building of walks, bridges, and drives. Before 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 surface.
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 combination of surface and subsurface drainage. Surface drainage takes care of the water that is likely to destroy the best appearance of lawns and planting spaces, and Subsurface drainage looks out for the draining of garden walks, tennis-courts, and the conducting of surplus water to proper outlets.
In considering the engineering features which have to do with topographical reconstruction, stable bridges, and well-graded roads, all these practical considerations must be subordinated to the esthetic ideal of the final appearance of the finished design. But if the practical considerations are satisfactorily determined, they .will actually contribute to the beautiful solution of the problem. The esthetic side of the question cannot be treated as an easily detached ornament quite apart from any vital connection with the design. No matter how useful a thing may be, we do not care for it if it is ugly. Beauty is consequently the vivifying influence, the most potent factor in determining the design scheme.
If the designer will keep in mind in a broad way the subjects which have been classed in the practical and esthetic divisions of landscape, they will be to him a rock of strength in solving his problems. Too often a petty insistence on details makes one lose sight of higher, more important things, and ruins a design which has great possibilities for beauty.