10 Reclamation of Batman's Swamp. 



into the Yarra and Salt Water Rivers. In the summer time 

 the water is evaporated from this basin, again to be filled by 

 the collected storm water in the rainy season ; or if a 

 southerly breeze, a freshet in the Yarra, and a full moon 

 should simultaneously occur, the greater part of the marsh, 

 and in some cases the whole of it, has been overspread with 

 water to a depth of several feet. In November, 1849, a com- 

 bination of the above circumstances covered the swamp to a 

 depth of 5 feet, and destroyed a considerable quantity of pro- 

 perty and goods in the wharf stores, and in the lower levels 

 of Flinders-street west. From marks made at the time of 

 the flood, I find that the average depth of water over the 

 swamp amounted, as said, to five feet. 



To reclaim this land from the inroads of the sea or bay, it 

 will be necessary to guard its confines by an embankment to 

 prevent a similar occurrence. This would do, as far as 

 regards reclamation from the waters of the bay, but if used 

 for cultivation, it must also be kept free, by drainage and 

 pumping, from the storm water descending into the basin 

 alluded to. 



In the ordinary state of the bay and river there is sufficient 

 fall to drain the basin, and to keep the entire surface of the 

 swamp free from water ; and it would only be in the event of 

 having a continued rain, on the one hand, or the rising of the 

 River Yarra, either by floods or the waters in the bay being 

 ponded back, on the other, that arterial drainage by machinery 

 would have to be resorted to. 



I will therefore advert to — 



1st. The method and cost of protecting the swamp from 

 the inroads of the sea, and 



2nd. The method of keeping the reclaimed land free from 

 storm water, and the cost of so doing. 



Upon measuring the irregular boundary of the entire 

 marsh, as shown on the accompanying plan, I find that it is 

 equal to 460 chains, or 5| miles, but as an embankment, for 

 reasons to be hereafter given, would only require to be con- 

 structed from the railway reserve, opposite the west end of 

 Little Collins-street, round by the Gas Works, the banks of 

 the Yarra, and the Salt Water River, to the punt, it would 

 only measure 250 chains, or Z\ miles. 



The soil of the swamp varies from 12 to 26 inches in depth, 

 and is composed of stiff alumina or argillaceous earth, strongly 

 impregnated with salt and gypsum. Immediately beneath 

 this, a stratum of sand, varying from six inches to two feet, 



