1074 



DRAINAGE 



DRAINAGE 



Drainage for landscape work. 



The value of a thorough knowledge of the possi- 

 bilities of drainage in landscape work has been over- 

 looked until recent years as a definite field entirely 

 apart from general drainage for agricultural purposes. 



Drainage under the headings of this article is in- 

 stalled with the following objects in view: 



1. Maintaining well-drained areas for firm lawn 

 surfaces. 



2. Maintaining well-drained and firm surface con- 

 ditions for recreation areas. 



TAR RAPE ft 



-& JO/NT 

 1353. Covering a joint. 



3. Draining of surface water and ground water from 

 roads. 



4. Draining foundations for walks. 



5. Preserving the normal soil conditions for newly 

 planted trees. 



6. Draining swamp and marsh areas to prevent 

 breeding of mosquitos. 



1. Drainage for lawns. 



The secret of a perfect lawn is attributed to drain- 

 age conditions which provide a well-drained subsoil and 

 a firm surface that may be readily freed from any excess 

 water during heavy rains. The installation of drain- 

 age for this purpose is required only in the more com- 

 pact soils that do not drain naturally. Sandy soils 

 seldom require artificial drainage unless immediately 

 underlaid with a stratum of impervious clay. On any 

 lawn the topography of which does not permit the 

 ready surface run-off and the subsoil of which is com- 

 pact clay, the necessity of installing sub-surface drain- 

 age is strongest. 



A drainage system for providing ideal soil conditions 

 for perfect lawns must be installed carefully. Four- 

 inch tile, is often used in the lateral systems while 

 either 6-inch vitrified pipe, or the No. 2 quality of 6- 

 inch round tile, is used for the main lines. All drains 

 should be laid on an even grade of not less than J/g of 

 an inch fall to each linear foot of drain, and preferably 

 not less than J4 of an inch fall for each foot of drain. 

 If perfect drainage is desired, the distance apart of 

 these drains should not exceed 20 feet. In accordance 

 with the general laws of drainage, tile should be laid 

 at a more shallow depth in the heavy soils than in the 

 lighter soils, and should be spaced at closer intervals 

 than 20 feet, this space varying largely with the desire 

 to free the lawn immediately of any excess surface 

 water. 



In all tile drainage whether for lawns or other pur- 

 poses, a space of approximately Y% inch should be 

 allowed between the ends of the pipes. The covering 

 of tar paper and cinders should be placed over each 

 joint as shown in Fig. 1353. The tile should be placed 

 on a firm bottom of clay or other natural soil, and sur- 

 rounded on all sides, and covered to a depth of not less 

 than 6 inches with cinders, crushed stone, or washed 



BACK /V 



gravel (Fig. 1354). In very heavy clay, the trench 

 excavated for the tile should be filled with cinders, 

 crushed stone or gravel to a line separating the looser 

 top soil from the clay subsoil (Fig. 1355). In heavy 

 soil and for perfect lawn drainage, the lines of tile 

 ought not to be laid deeper than l}/^ feet and the cin- 

 der fill should not be less than 15 inches in depth. In 

 the lighter sandy loam soils, the tile may be laid to a 

 depth of 3 to 3^ feet. 



It is often found necessary when lawns are con- 

 structed on sandy soil to prevent excessive drainage, 

 rather than to encourage drainage conditions. In these 

 extreme sandy soils, the surface water seeps away so 

 readily that the lawns become exceedingly dry during 

 the warm and dry months. To prevent this condition 

 a layer of clay 4 inches deep should be distributed over 

 the sandy sub-grade prepared for the lawn, at a depth 

 varying between 10 and 18 inches below the proposed 

 finished surface of the lawn. This clay is thoroughly 

 compacted and serves as a partial barrier against 

 abnormal seepage which would otherwise occur, and 

 thereby retains the moisture necessary for the capil- 

 lary attraction to feed the roots of the lawn grasses. 



2, Recreation areas. 



Areas naturally falling under this heading are' 

 tennis-courts (clay and turf), bowling-greens, clock- 

 golf areas, and croquet -lawns. All of these require 

 a more careful study of drainage conditions than is 



GRADE 



GRADE. 



TOP SO/L 



.'. CINDERS;- 

 ";v OR ^': 



llGRAVEL^ 



'i'. "-.*. 'V. *J.v'.^ 







B'rALL FROM BACK NET TO CENTCR- 



^ RIPE. 

 1354. The filling of a drain. 1355. Applying good top soil. 



given to the average lawn. It is essential that such 

 areas be so completely drained that the surface con- 

 dition is always firm, even after the average continuous 

 heavy rains. 



Tennis-courts. These areas require the most care- 

 ful study of drainage conditions. The average tennis- 

 court requires two types of drainage, surface and 

 sub-surface. Surface drainage is cared for in two ways, 

 (1) either by giving the court a gradual slope to one 

 end, or (2) as shown in Fig. 1356, where the surface of 

 the court is sloped from either end toward the middle 

 line. This method, shown in Fig. 1357, gives probably 

 the most satisfactory results, because, in this way, if 

 surface conditions at the middle of the court are cor- 

 rect, the surface water is cared for most readily and 

 with the shortest possible run-off. This drain across 

 the middle of the court may be either an open concrete 

 drain with a plank laid over the top and flush with the 

 surface of the court, or a blind drain filled with a 



CLAY" BINDING GRAVEL OR STONE SCREENINGS^ 



^V CINDERS OR CRUSHED STONE I 



1356. Draining a tennis-court. 



