22 



REPORTS ON TORONTO HARBOUR. 



Certain outward and inward currents occasionally exist at the 

 entrance, caused probably by gales slightly varying the level of por- 

 tions of the lake, or, as it is also supposed, by local variations of the 

 atmospheric pressure on its surface ; these may assist to a limited 

 extent in prolonging the existence of the channel, but from all the 

 observations I have as yet been able to make, they appear to be surface 

 currents only, having little or no appreciable effect five or six feet under 

 water : even this supposition therefore is very problematical. 



ITS PRESERVATION. 



Having by sufficient evidence set forth the probability if not the 

 certainty of an early destruction of the Harbour by the damming up 

 of its entrance, we may now proceed to the practical, and so far as the 

 commercial interests of Toronto are concerned, the vitally important 

 part of the inquiry, and endeavour to obtain a satisfactory answer to 

 the query — How can such a catastrophe be obviated or indefinitely 

 postponed? A problem which becomes of comparative easy solution 

 when the immediate cause of the evil is set beyond a doubt, and the 

 nature of its operations clearly ascertained. 



To keep those Harbour channels subject to obstruction from moving 

 sand-bars in a navigable condition, three expedients are generally 

 resorted to : First, continuous or periodical dredging ; second, the 

 application of a scour to remove the bar as it is formed ; third, the 

 construction of such works as are calculated to prevent the deposition 

 of the sand in the channels, by retaining it at a distance, when its 

 source is known, or by diverting it to those points where depth of 

 water is not essentially necessary. 



The first is often applied as a temporary remedy, and as such may 

 at times be viewed as a fit expedient, but to employ it as the lasting 

 counteracter of a constantly increasing evil, is to adopt an indubitable 

 source of unceasing attention and endless outlay ; it should accordingly 

 be dreaded as a permanent restorative, and employed only by compul- 

 sion from unusual difficulty in the application of other measures that 

 are generally less costly and always more satisfactory. 



The second is obtained at marine ports by taking advantage of the 

 tidal fluctuations, and is generally produced twice each day by using 

 the currents of rivers -at low tide, or by holding up the sea water in 

 large artificial basins at flood, then concentrating and guiding it to the 

 bar at ebb. The impracticability of procuring a scour on Lake 

 Ontario from tidal fluctuations must be admitted, since practically there 

 are none ; true it is we have a gradual rise and fall of about two feet 

 annually, and at times successive oscillations in level to the extent of 

 several inches, much resembling small tidal waves ; but the latter 

 although they give to the surface water at the entrance of the Harbour 

 a perceptible current, are too rare and too feeble to be of any real 

 value. Nor have we at Toronto a river sufficient for the service ; for 

 the Don has hitherto failed to keep open its own channel to a greater 

 depth than two or three feet. Indeed I feel quite convinced that all 

 attempts on these inland waters to keep permanently open those har- 

 bour channels much exposed to beach drifts by other than the largest 

 class of rivers must sooner or later prove inneffectual. The currents 

 of the Nottawasaga, of the Sable, and of the Saugeen, are unable to 

 keep open to a sufficient depth or width the mouths of those rivers, 

 and yet they are in volume from ten to twenty times greater than the 

 Don. 



The third remedy can always be advantageously employed in cases 

 when the obstructions are the natural results of moving beaches, and 

 when the works are located and executed with proper care they 

 usually answer a good purpose ; the second is often after great outlay 

 under favourable circumstances of doubtful efficacy. In the case of 

 Toronto, even if we had at command a current capable of removing 



the sand on its arrival at the point of the shoal, I question very much 

 if it should be considered as more than an auxiliary, since it would of 

 necessity tend to spread the deposit, and thus, although injuring the 

 channel in a less degree, would impair the Harbour generally by 

 lessening in depth the approach to it. Without doubt the steps likely 

 to confer the greatest security, and hence the most a Ivisable to be 

 taken, are those which are calculated to keep the drift at a distance 

 from that point where it is not wanted. 



I therefore beg leave to submit for your consideration the following 

 preventive and remedial measures : — 



1st. That a Groyne should be constructed at the Lighthouse point 

 from the shore outward to 8 or 9 feet water for the retention of the 

 moving sand, on the principle of those very simple natural ones shown 

 by Figs. 6, 7, and 8. 



2nd. That an auxiliary Groyne be run westerly across the outer edge 

 of the shallows, a little to the south of Gibralter point. 



3rd. That a Pier or breakwater be built along the south side of the 

 channel as shown on Fig. 21, increasing the navigable water to six 

 hundred feet, by cutting off the point of the shoal north of the proposed 

 line of pier. 



The third alone would probably suffice for many years to keep the 

 channel perfectly free from deposit ; but the sand, if not retained at 

 the Lighthouse point, would as at present be moved northward by 

 the southerly waves, and would gradually accumulate to such an ex- 

 tent as to fill up the whole space along the south side of the pier until 

 ultimately rounding its extremities. To effectually prevent this the 

 first and second should also be constructed, the first would divert the 

 drift westerly into deep water, where the navigation could never prac- 

 tically be obstructed ; and the second groyne placed about midway 

 between the first and third would have the effect of counteracting all 

 progressive action along the west end of the Peninsula. 



If the destruction of the Harbour entrance, and the formation of the 

 Peninsula generally, be satisfactorily determined, I think it is equally 

 conclusive that these works, or works of the same character, would, 

 if established in due time, be exercised to a very beneficial result — the 

 preservation of the Harbour for an indefinitely long period. 



There are other evils, which, if they affect the salubrity of the city 

 more immediately than they prove detrimental to the Harbour, are 

 not on that account of the less consequence. The Don annually trans- 

 ports even at this day considerable quantities of silt from the interior 

 of the country to the Marsh, and, during freshets, a portion escapes 

 from thence into the Harbour through the openings in the beach 

 between the Wind-mill and Privat's, tending of course, when deposited 

 in the basin, to lessen its depth. All the drains and sewers empty into 

 the bay, making it, in truth, the grand cess-pool for a population of 

 probably 30,000 inhabitants, with their horses and cattle. The sewers 

 of necessity bring down no inconsiderable portion of solid matter, 

 imparing greatly the purity of the water in the Harbour, as well as 

 gradually lessening its depth. This evil, increasing in a proportionate 

 ratio to the growth of the city, might be greatly ameliorated, if not 

 almost totally removed, by the construction of a main sewer along the 

 whole city front eastward to the Marsh. Into this sewer all the lateral 

 ones from the north, and the drainage of gas, chemical and other such 

 like works should be made to discharge. The feculent mixtures pro- 

 duced would thus be collected and conveyed to a distant point, where, 

 by similar operations to those now ripening in Britain, which will 

 strip them not only of their noxious, but even of their offensive cha- 

 racters, might be profitably converted into a marketable commodity 

 of the highest value to the farmer. 



