72 Remarhs on th-e Report of the TVater Commission. 



But suppose this objection to be valid, tbere is still a resource. 

 Although I do not consider it absolutely necessary to take any 

 special precaution against what I regard as an improbable con- 

 tingency, still such a precaution is perfectly feasible. If one 

 dam will not be a perfect protection against the percolation of 

 salt water, it does not require any great stretch of the inventive 

 faculty to suggest the construction of two. A second and 

 outer dam might be made either from Doll's Point to Towrah, or 

 from Stripper's Point to Pelican Point. Though not absolutely 

 essential this is the plan I should most recommend, as the addi- 

 tional expense would be more than compensated by the additional 

 assurance ; and in a matter of such importance to the community 

 it is proper to eliminate risk as far as it can be done without 

 incurring disproportionate outlay. With two dams we should 

 have the following state of matters. There would be two lakes 

 — an outer and an inner. In ordinary seasons the outer would 

 receive the first water discharged over the weir, and the water in 

 it would in course of time become fresh. But none of this water 

 would be pumped out for the use of the city, nor would it rise 

 and fall with the tide. It would stand at a constant level. In 

 the case of the supposed drought, therefore, which completely 

 dried up the bed of G-eorge's River, this outer reservoir would be 

 full, less only the loss by evaporation, and the water in it would 

 be substantially, if not perfectly, fresh. If any salt water should 

 ooze through the outer dam, it could only be in small quantities, 

 and it would only very slightly affect the large body of water in 

 this outer reservoir, and it would only be this very slightly 

 brackish water that could find its way through the inner dam. 

 The dilution, therefore, in the inner reservoir would be infi- 

 nitesimal. 



If it should be determined to adopt, from the very first, the 

 system of a double dam, then, if the outer one were constructed 

 first, some modification might be made in the suggested structure 

 of the inner one, as it would not be exposed to any tidal action ; 

 and its cost and difficulty of construction would be diminished. 



On the double dam system, too, it might be thought expedient 

 to make the outer dam from Doll's Point to Towrah, and the 

 inner dam from Stripper's Point to Pelican Point. This would 

 involve some deviations from the plan I have suggested, which, 

 however, it is not worth while to discuss in detail, I mention it 

 just to show that any engineer who may be called upon to design 

 works for sweetening George's River is not shut up to one plan, 

 but has several alternatives befose him. Of course, the lower 

 the inner dam is placed down the river, the larger is the area of 

 the inner reservoir, and though Wooloware Bay is shallow and 

 mostly dry at low water, its inclusion would add fully a thousand 

 acres to the storage capacity of the river. 



