24 BtTLLETIX 724, U. S. DEPARTMENT OF AGRICULTURE. 



the concrete to be mixed in tlie proportion 1 part cement. 2 parts sand, 4 parts 

 crnslied stone or gravel ; tlie gutter to be given a 1 : 2 mortar finisli and to bave 

 a total depth of 6 inches. 



Materials reqnired pi>r sqnare yard of gutter : 



Portland cement, 0.25 to 0.30 barrel. 



Sand, 0.070 to O.OSO cubic yard. 



Crushed stone or gravel, 0.14 to 0.1.5 cubic yard. 



Tar paper or bituminous felt, . 



(If the mortar sui-face is omitted, this would reduce the cost aliout H or 6 

 cents per square yard.) 



Third, consider a brick gutter, figure 7, similar in cross section to the cobble 

 gutter, the foundation to be of crushed stone or gravel, the paving to consist of 

 vitrified paving brick laid on edge with the long dimensions in the longitudinal 

 direction and the joints to be filled with Portland-cement grout. 



^laterials required per square yard of gutter : 



Foundation, 0.20 cubic yard crushed .stone or gravel. 



Sand bedding, 0.05-5 cubic yard sand. 



Paving, 40 paving brick. 



Grout, 0.03 to 0.04 661 cement, 0.014 to 0.16 cubic feet of sand. 



DROP INLETS AND CATCH BASINS. 



Drop inlets and catch basins are used to conduct water from side 

 ditches or gutters intck underground drains or culverts. On country 

 roads the}^ are used most frequently on side-hill locations where the 

 water collecting in the upper side ditch or gutter can be removed from 

 the road at intervals by means of a culvert across to the lower side. 

 Where the development contiguous to the road is suburban in char- 

 acter tliey may be required by a variety of conditions. Drop inlets 

 usually are sufficient for this purpose and catch basins seldom are 

 used in country-road work, except where it is especially desirable to 

 prevent the silt and other foreign material carried by the water from 

 getting into the underground drainage structure. 



Where catch basins or drop inlets are to be used, their location and 

 design are of especial importance. It is almost as common a fault, 

 however, to omit them as to introduce them improperly into the drain- 

 age system. As indicated above, they are used to relieve the upper 

 ditch or gutter and therefore have a close relation to the capacity of 

 such gutter and its tendency to erode. Rightly placed, they afford a 

 means of controlling the amount of water delivered by successive sec- 

 tions of gutter to the sections immediately adjacent, and enabling a 

 gutter of uniform cross section to be designed for long .slopes. In 

 handling hillside drainage it is good practice to clear the gutters at 

 the crest of the grade. If water has been brought across a flat to the 

 top of a hill it is likely that in heavy rains the hillside ditches will 

 be overcharged unless relieved at frequent intervals. Culverts placed 

 under the road to provide such relief should have some form of in- 

 take that will direct water into them. The drop inlet may be used for 



