XXXI 



The River Lea is a small sluggish stream draining part of Hertford- 

 shire and Middlesex. The lower part of itis canalised, and from the upper 

 part of it the main supply of the East London Waterworks Co. is taken 

 ihe company take all the water except what they are forced to leave 

 lor working the navigation. The water thus left is to all intents stag- 

 nant, like that of all other navigable canals— the only current being 

 that caused by the use of the locks. And as the river and canal 

 recede the sewage of all the chief towns of Hertfordshire, and of much 

 or London itself, it may be said that the whole affair at the London end 

 w but a common sewer used as a canal, as the quantity of sewage it 

 Receives from a population of more than 20 times that of Hobart is there 

 its main water supply. A population of 200 millions draining into 

 tee Lerwent would not render it so noisome as the Lea, even supposing 

 the former to be as stagnant as the latter. Consequently the case of 

 the Lea is not one in point. 



Again, after stating the fact that the total solid matter in the 

 uobart sewage would be 10-35 tons daily, of which L66 tons would 

 De solid fecal mater in a state of " 

 Water, the report goes on. 



dilution of one part in 4,400 of 



CONDITIONS or DISCHARGE. 

 Another point in connection with this matter has to be considered. 

 •Lhe above given rate of dilution of the sewage is that in the sewers 

 hetore discharge : what will be its condition after discharge ? The 

 accompanying plan shows that it is to be sent into the tideway of 

 the estuary. The capacity of the basin of the estuary in front of 

 fiobart and between the outfalls is at least 00,000,000 (sixty million) 

 ons._ This quantity of water is in continual motion from the action 

 " r wind and tide and the downward current of the river. This down- 

 ward current is caused by the flow of the drainage from about 3,000,000 

 wes of land— a flow equal to a daily average of 15,000,000 (15 million) 

 ns of fresh water, being seven times that in the Thames at London, 

 is evident that the actios of this downward current and of t*he 

 Ues must change a great part of the water in this portion of the 



sorT? every day ' What would be the effeet o£ turnil § if tons of 



; m i£ecal matter in the above-described weak solution into this 



mense body of continually moving and continually renovated water 



certainly would not be appreciable. Water is considered pure and 



oiesome for drinking purposes when it does not contain more than 



est, Part m 4 ' 000 ' 000 ( four million) of combined nitrogen. But the 



sew y Water cannot he used for drinking, and even if it could, the 



^age would not add to its combined nitrogen one part in 40 



»ai+ "p^u * haVe ' therefore, no hesitation in recommending that this 



? t ot the sewage should be treated as the rest, and together with it 



conveyed by the sewers into the tideway of the estuary. 



LIVERPOOL SIMILARLY SITUATED TO HOBART. 



also h «rf- P ° Slt j 0n ° f LiTOr P° o1 is ver y similar to that of Kobart; it being 

 more tk " p0n a tidal estuar y- But the population of Liverpool is 



form- Tu (twenty-six) times that of Hobart, and the area of land 

 basin f *l e d If lna S e basin of th e Mersey is not half that of the drainage 

 be m m ■ Derwent > so that the mean outflow of the former cannot 

 Poll, ? 1S i , hai£ that of the latfce r. Moreover, the Mersey is already 

 (two Mr ° Ijlvor P° o1 wi th the sewage of more than 2,000,000 

 of 20WUW P e0 P le : the Derwent above Hobart does not receive that 

 closel- + (twenty thousand.) Liverpool is now altogether a water- 

 anrt ? W "' dramod into sewers which discharge into the 



"a notwithstanding all the above c 



'ore adverse than those of Hobart— 



The 



estuary ; 

 circumstances — so incomparably 

 no inconvenience is felt either 



