COLOSSAL WORK IN BALTIMORE 



A COMPLETED SECTION OF THE OUTFALL, SEWER 



of pipes is used in connection with dams, 

 the small pipe being for the summer 

 flows, which keep it under pressure. 

 Should a rain cause the flow to increase, 

 it rises over a dam, discharging into a 

 larger pipe, with still another pipe in re- 

 serve, with a higher dam to take care of a 

 cloud-burst, thereby putting all the pipes 

 under pressure, scouring them out by the 

 water in the reserve order, until the flow 

 is back in the small pipe, which pipe is 

 under constant pressure by the dry- 

 weather flow. 



Concrete is being used to a great ex- 

 tent, and wonders are being moulded 

 under the city with this concrete con- 

 struction. 



The storm-water flows directly into 

 the harbor or to Jones' Falls, a stream 

 passing through the city. 



Two-thirds of the sanitary sewage of 



the city is intercepted by what is called 

 the high-level intercepter, and is carried: 

 by gravity to the disposal works located 

 on Back River. These works, when com- 

 pleted, will be capable of treating 300,- 

 000,000 gallons a day. The sewage 

 from the other third of the city, lying, 

 around the harbor and below the high- 

 level intercepter, is carried to a pump- 

 ing station by an east and a west low- 

 level intercepter. There the sewage is 

 lifted from about 13 feet below tide, a 

 height of 72 feet, including friction, by 

 huge pumps, each capable of lifting 

 27,500,000 gallons a day. The photo- 

 graph on page 368 shows one of the five 

 pumps to be installed, now under con- 

 struction. These pumps lift the sewage 

 through iron force-mains to the high- 

 level intercepter, whence it flows by grav- 

 ity to the disposal plant. 



