CONSTRUCTION NOTES 2 4 j 



(d) Foundation walls. (Include retaining walls, cellar walls and pools.) 

 Such walls must invariably be protected by a line of drain tile installed 

 immediately at the base and on the back of the wall and discharging by 

 tile drains or weep holes in order to remove the surplus ground water that 

 will otherwise cause damage by frost action, or seepage through the wall. 



(e) Wooded areas. The drainage problem of wooded areas is prefer- 

 ably solved by open channels for the surface water, and lines of drain pipe 

 where necessary to remove the ground water, especially in picnic areas and 

 woods which are frequently used during the wet season. These drains 

 should be installed with the greatest of care in order that the natural ground 

 water conditions in the soil may be changed very gradually, thus per- 

 mitting the root systems of the trees to readapt themselves to the changed 

 moisture conditions of the soil. 



(/) Cemeteries. In cemetery drainage, besides modeling the surface of 

 the ground so far as possible in order to remove to proper inlets and catch 

 basins the surplus surface water, there is also an important problem of 

 providing drainage, especially in the heavier types of soil, for each grave 

 by installing a line of drainage below the level of the grave similar to figure I 

 on Plate 108. 



(g) Recreational areas. The drainage of .recreational areas is one of the 

 most important problems of drainage. Such areas as playgrounds, tennis 

 courts, bowling greens, polo fields and baseball fields must present a firm 

 surface soil condition at all times and must be as little affected as possible 

 by storm water which should be removed in the shortest time both by 

 surface drains and by underground drains. It becomes necessary to install 

 drainage on these areas with short intervals between the parallel lines of 

 drains, especially where such areas are constructed on the various types of 

 clay soil. 



(h) Steep bluffs having a tendency to disintegrate and slip in large 

 sections on the face of the slope. These conditions present a problem of 

 removing all surface water before it reaches the top of the slope and usually 

 of removing all ground water through the installation of a deep line of drain 

 tile in the bottom of a cinder filled trench. Figure I on Plate 108 is for the 

 purpose of intercepting such ground water as will eventually find its way 

 to the lower impermeable hardpan subsoil and follow this layer to the face 

 of the slope. 



(i) Meter pits, boiler rooms, newly transplanted trees, etc. These areas 

 should always be thoroughly drained. This is important with tree pits 

 especially when made in the heavy type of clay soil. 



Kinds of pipe used for drainage. The two most common kinds of pipe 

 used for drainage purposes, so far as this discussion is concerned, are agri- 



