CONSTRUCTION OF WALKS AND DRIVES 



63 



stone. Side walls should be six inches thick plumb, and an opening 

 left for the outlet pipe one foot above the bottom of the basin. This 

 will allow a space for the sand and debris to collect. 



The side walls for brick catch basins should be at least nine 

 inches thick, built of straight, hard, building bricks that will ring 

 clear when hit together. They should be laid in a Portland cement 

 mortar consisting of one part cement to two parts of sharp sand. 



Fig. 63. — A good type of 

 catch basin grating 



Fig. 64. — A catch basin designed to receive a 

 large volume of water 



GRATINGS 



Catch basins should be provided with gratings (Fig. 63) with 

 ample open spaces between the bars for a free intake of all water. 

 Small openings become clogged with leaves and are useless. 



Where a large volume of water is to be taken care of it is well 

 to build the basin back six or eight inches beyond the iron grating 

 and place a coping stone over it, with an opening three inches wide, 

 for the full length of the grating (Fig. 64). 



CONNECTING CATCH BASINS WITH DRAINAGE LINES 



Where road drainage is connected to the sewage disposal system 

 it is necessary to have a running trap between the sewerage line and 

 each connection with the catch basins. In this event care should 

 be exercised to see that all pieces of pipe are free from flaws and the 

 joints packed with oakum before cementing the sections together. 



