276 PARKS 



on steep slopes. Gutters constructed as shown in Plate 113, figure 2, are 

 not desirable. It should be kept in mind that the flow of water over turf 

 gutters brings a certain amount of soil from the surrounding areas. This 

 soil constantly deposited in the gutter and held by the growing turf will 

 in a period of years tend to lessen the depth of the gutter and, therefore, 

 its efficiency. For this reason it is suggested that turf gutters should be 

 constructed adequately deep. 



VI. Brick Gutters. Brick gutters are usually desirable with brick 

 roads, and sometimes with concrete roads (Plate 114, figure i). In such 

 instances the subsoil under the gutter should be thoroughly drained and 

 the brick should be laid with a sand cushion upon a concrete foundation. 

 The average width of a brick gutter is between three and four feet, and 

 the average depth at the middle line of the gutter is approximately three 

 inches. The exact width of the gutter for purposes of economy is often 

 determined by the size of the brick and by the detailed plan for laying in 

 order to avoid unnecessary cutting of the brick. Where the brick surface 

 or traveled roadbed is grouted with cement it is desirable to grout the 

 surface of the brick gutter. 



VII. Concrete Gutters. Concrete gutters are usually constructed in 

 connection with concrete drives (Plate 113, figure 3) and more often as a 

 combination curb and gutter (Plate 114, figure 4). The dimensions for the 

 width and depth of a concrete gutter are the same as those for a brick 

 gutter. The wearing surface plus the concrete foundation should approxi- 

 mate seven or eight inches as a minimum depth. The gutter should be 

 placed upon a firm foundation of thoroughly drained cinders. The wearing 

 surface, about one inch in depth, should consist of a cement mortar. The 

 method of curing and of protecting concrete gutters is the same as that for 

 concrete curbs. 



VIII. Cobblestone Gutters. Cobblestone gutters may be used to excellent 

 advantage in connection with macadam entrance drives on steep grades or 

 sharp curves where the erosion from surface drainage may be excessive. 

 The width and depth of the cobblestone gutters (Plate 114, figure 3) approxi- 

 mates the same dimensions as those required for brick gutters and concrete 

 gutters. The stone is often laid upon a sand cushion two to three inches 

 deep, all of which is placed upon a concrete foundation. The minimum 

 thickness of the concrete foundation should be about five inches. The voids 

 between the stones in the gutter should be filled with sand or sandy loam. 

 This material should be swept over the surface of the cobbles and wet at 

 frequent intervals to ensure the filling of all voids. It is sometimes desirable, 

 where the gutter is subject to extreme wash, to grout these stones with a 

 dry mixture of sand and cement (i to 2^) This mixture, after being swept 



