\v VIKK STAC;K KKI.I>TKK> in 



A* usually designed the sewers are for practical reasons of 

 ample cross~sect -l-.id .1 wide n. \. With 



raw sewage being discharged into natural waterways little aitm- 

 ii"ii has been paid h -i- ! the* quantity discharged, and 



few cities have any re* nal discharge of their 



sewer- In many cases the low dilution of the sewage by the 

 ii.tim.il mi in( win. h it lias been discharged, 



especially at limes of lw flow, ban IM . (1 the cause of many 

 nuisances. ! Mates have passed laws governing the 



I i --barge of sewag* itate waters and investigations 



upon win. h to hase a Federal law, co\ trrstatc streams, 



are now under way. All such investigations require a 

 knowledge of stream flow. In fart, the question of whether 

 the sewage from a proposed or -\i*tm^ -rwrr system may be 

 discharged into a given stream may be almost mtin-K ! - 



i the basis of tin* quant ii\ of sewage and the minimum flow 

 of tl n. hoth of whieh <|u.intiti'-s it is poftsilil'- to deter- 



ruin.' roinplrl.-K |,\ flu- n^r <i| (,url-\ nirn-nt rm-ters and 



f u.it.-r stage registers. 



The flow of all stream- into \\lii.-h sewage is discharged 

 IH a matter of record in every rit\ that dinposes of it- 

 sewage in tin- way. Such information may be obtained readiK 

 by means of tin- current m.-t.-i !n.-tli...| of stream gaging, 

 <-\plain<-d on pages 48 to 62. 



It is also possible to apply current meter methods to the 

 mea-uremenl of the (l<w in the -ewi-r-. ihein-elxi'S. In appl) in 

 th--e iiieihiuU. it will he po*>ihlr to fuul or to construct in the 

 sewer barrel a permanent rontrol - lion to be rated. Because 

 of the relatively large diurnal flin -tuations of depth over the 

 eontrol to he e\|>ected from the character of sewage discharge, 

 it i- necessary to use automatic re-iMrrs. For thU purpose, 

 (iurleN (Graphic I?e^i-ter No. 631, with a normal range of one 

 foot, de-i-rihed on pa^es 1 1 1 to 1 16, is nio-t -uitahle. 'Hie float 

 chamhet >houhl be designed as a part of the sewrr il^-lf and 

 built at the same time the sewer is. In case of existing sewers 

 on which it is desired to keep records of flow, a well for the float 

 may be built alongside the sewer at the proper point in its 

 length. Gagings of thjs character have been carried on sue- 



