On t%e botany WatersJied. 83 



of the Earidwick Eoad, extending from opposite the new toll- 

 house to the rocks opposite the Eace -course gate. The chief 

 part of the materials for forming this embankment may be taken 

 from the sand and bog on the north side of the embankment, 

 and thus form a canal of five chains mean width along the whole 

 length of the embankment to retain water. In addition to this 

 canal, a reservoir should be excavated in the valley between two 

 hills extending from the Eandwick Road to near the mouth of 

 the tunnel. This embankment with the reservoir and canal will 

 retain 473 millions of gallons of water. It will also serve 

 another highly important purpose, by impounding the head 

 waters which now run off so rapidly in consequence of the great 

 declivity of this part of the watershed, it will prevent floods in 

 the neighbourhood of the lower dams, which now at considerable 

 risk have to bear the brunt of the whole rush from this and the 

 entire watershed between the Lachlan and No. 6 Dam during 

 extraordinary rainfall ; in fact no dams below the Eandwick 

 Eoad, be they constructed ever so expensively, can ever be 

 deemed safe, until an embankment capable of checking the head 

 waters to a large extent is made in the locality of the Lachlan 

 Swamp. It would be premature to erect machinery for pumping 

 all the water at our disposal into Sydney, until a sufficient 

 number of dams has been made across the course of the stream 

 to arrest the storm waters from approaching the sea so rapidly 

 as they do now, and by those means retain them until they can 

 be pumped into Sydney. At the latter end of the year 1858, 

 when I first put the Botany engines in motion we had no dam 

 whatever, but the engine-pond dam on the sea-shore, to hold 

 back sufficient water for supplying the engines. This answered 

 the purpose entirely, until in the years 1862, '63 and '64 water 

 mains were extended throughout the city and into many of the 

 suburban boroughs. From the fact of the storage accommoda- 

 tion not having been increased simultaneously with the extension 

 of the mains or means of distribution and consumption, we 

 began, in the months of January, Pebruary, and March, of 

 '. 865, to feel the want of some of the water which had 

 been allowed to run into the sea during the rainy season. 

 This led to the construction of some dams across the 

 stream to retain the water and conserve it to supplement the 

 stream in the dry season. The number of dams proposed to be 

 made, including that of the engine and upper mill-ponds, was 

 fifteen in all ; three of these and the upper mill dam were made 

 in 1867 and 1868, and brought into successful operation in the 

 latter year, when we had in all five dams capable of heading up 

 and retaining 174 millions of gallons. This quantity was 

 sufficient in the dry seasons of 1869 and 1870 so to supplement 

 the stream and give such a good supply in the months of 



