86 On the Botany Watershed. 



So tlie 4|- gallons per foot of this year's rainfall, shown to be 

 absorbed by the sand, is in addition to the quantity which 

 remained there when the rain commenced in February last. 

 Thus we go on from year to year, with, in fact, a reservoir so 

 covered and protected by nature as to prevent loss by evapora- 

 tion, and which yields again to us all it takes under its influence. 

 The quantity of rainfall so retained in the sand not actually 

 accounted for is, in fact, constantly percolating through it, and, 

 being replenished by occasional light showers, and by the very 

 heavy dews which fall upon this catchment. This water it is 

 which augments our Botany stream during the dry months of 

 December, January, and part of February. This stream, with 

 the assistance of 17-i millions of gallons which were stored in 

 the wet season of 1869 in the five existing dams, kept Sydney 

 and the suburbs supplied during the dry season of 1869 — from 

 26th July to the 26th February, 1870 — a term of seven months, 

 during which time only 15'25 inches, 2 1-6 inches per month, 

 or a shade over l-16th of an inch daily for 215 days. From 

 these facts I conclude that the loss from evaporation on the 

 Botany catchment is very slight indeed, and if the whole of 

 the water which ran into the sea to the 31st August could have 

 been pumped into the storage reservoir I have suggested, and 

 that reservoir had been covered, the evaporation from it would 

 not have been felt. 



It is therefore, palpable that the plan I projected in 

 1868, and published in the " Si/cbiet/ Morning Herald^' 

 of the 8th Slarch, 1869, should be carried into efl'ect for 

 increasing the supply of water to Sydney and the suburbs, so as 

 to suffice for a population of 400,000. It was as follows : — a. 

 To construct a large impounding reservoir near Sydney, at the 

 Cemetery reserve, b. To construct an embankment, and so form 

 another reservoir at the Lachlan Swamp. (Their contents com- 

 bined would be equal to 1073 millions.) c. To increase the 

 number of dams on the Lachlan stream, d. To send all the 

 water pumped from Botany into the Cemetery reservoir to 

 supply the present low level reservoir, and the greater part of 

 the town and suburbs from it, by gravitation, e. To establish 

 a pumring station near the Cemetery reservoir, and pump from 

 it all water required for the high levels of Sydney, Paddington, 

 and the suburbs. By this means I shall divide the present 

 heavy column, or lift of 214 feet, and so avoid all danger to the 

 thirtv-inch main from Botany. I shall also require an increase 

 in the number of engines at Botany, and enable the present 

 engines to send in a larger quantity of water by reducing the 

 lift and increasing the size of the pumps. This project of 

 mine was adopted and brought forward by the Water Commission 



