1 6 LANDSCAPE GARDEN SERIES 



The digging of each ditch should begin at its outlet. As the ditch 

 is dug the topsoil should be thrown on one side and the subsoil on 

 the other if it is desirable to have the topsoil replaced on top, as is 

 generally the case. A ditch 11 to 12 inches wide at top and 1 

 inches wide at the bottom generally suffices. The bottom of the ditch 

 should be of even gradient and hollowed or troughed to receive the tile. 



The minimum fall for a line of tile is 2 inches in 1 00 feet, unless 

 the laying is very accurate. The elevations or grades have to be fig- 

 ured out before excavation starts. Levels are taken by means of a 

 leveling instrument. A simple home-made device for this purpose com- 

 prises a one-legged stand with the leg sharpened so that it can be thrust 

 into the ground to hold the stand comparatively level and firm. On the 

 stand a carpenter's level can be placed, thus providing a line of sight. 

 The use of an improvised leveling rod will enable the taking of read- 

 ings and the determinations of the different elevations. Elevations are 

 generally given as meaning the elevations at which the bottom of the 

 tile will be placed (invert elevation). These elevations are marked on 

 stakes and followed in digging the ditches and laying the pipe. 



The tile laying should proceed from the outlet. In laying porous 

 tile it is important to avoid large open joints. After laying, the joints 

 should be covered with tar paper or burlap. The ditch can then be 

 filled with the soil or other material. The efficiency of the tile is 

 greatly increased by using material through which water can easily 

 pass, but which will exclude silt and sediment from the pipe. In this 

 case the tile can be covered with a layer 1 foot thick (measured from 

 bottom of ditch) of coarse screened gravel free from broken stones, 

 the largest of which does not exceed 2 inches in the largest diameter, 

 or cinders. 



The last few tiles at the outlet should be vitrified tile and the out- 

 let, if above ground, should be protected as described for storm drain- 

 age systems. 



LAWNS 



There is no element that can contribute more to the beauty and 

 attractiveness of a place than the lawn. It is the lawn which carpets 

 the open spaces and forms a setting for the house and planting. The 

 element of beauty which lies in an expanse of velvety green, patterned 



