26 



REPORTS ON TORONTO HARBOUR. 



such I believe it to be in the widest acceptation of the term — being- 

 doubtful that the problem of what its effects upon the harbor will 

 be can be satisfactorily solved beforehand. It may prove im- 

 mensely detrimental to the bay in drifting in vast quantities of 

 silt and shingle ; or it may simply fail to accomplish the end in- 

 tended by working out its own destruction by silting up more 

 rapidly than the dredge could free it. None I think will deny that 

 one or other of these results is amongst the possible contingencies 

 waiting on the experiment in question ; and though I have not 

 given the matter the attention necessary to enable me to pronounce 

 confidently on the above points, I must record my opinion that the 

 new channel would not be a self-sustaining one, and that its effect 

 upon tUe present entrance would be the reverse of beneficial." 



Mr. Kivas Tully says, 10th February, 1853: — "I would now 

 direct attention to the eastern entrance, which has been lately 

 formed, and which I venture to predict will not be closed again." 

 And, further, he says: " The breach which has been made lately 

 at that portion of the peninsula called the Narrows, about half a 

 mile east of Privat's tavern, shews the practicability of construct- 

 ing an eastern entrance, and it is not likely that this new channel 

 will ever be filled up from natural causes. I examined this chan- 

 nel on the 8th inst. It is about fifty yards wide and three feet in 

 depth, with a current of about two miles an hour running through 

 it in a south-easterly direction. The wind blowing strong at the 

 time from the S.S.W., the current was quite sufficient to keep the 

 channel clear of the sand which was washing into the entrance 

 with the return of the waves, which were pretty high at the time. 

 At all times there will be a current through this channel, either 

 into or out of the harbor. During the prevalence of an easterly 

 gale the current will be inwards at the eastern and outwards at 

 the western entrance ; and during a westerly gale this action will 

 be reversed, and the velocity of these currents will be sufficient to 

 keep both entrances open." 



Captain Richardson says, January, 1854: — "The boundaries of 

 the harbor being of sand, unless known physical laws be sus- 

 pended for the benefit of Toronto harbor, a current through it will 

 accelerate its nan." ' ; I will here simply state my opinion on the 

 effect that a canal 200 feet wide and twelve feet deep at the Nar- 

 rows would have upon the harbor : During a strong S. W. wind 

 it would cause such a current over the bar and along the south 

 side of it (judging from the effects as now seen at the breach) as 

 not only to deluge the harbor with sand, but in a short time to 

 sweep away block-house point and all the inequalities of the north 

 side of the peninsula, and convert the harbor into a wide-mouthed 

 bay, at the expense of the east end of it first. With the peninsula 

 intact all gales are favorable to the channel and maintainancc of 

 the bar. During a breach in the peninsula all high winds are 

 more or less destructive to the harbor." " The present breach by 

 the lake at the Narrows is similar to the warning shock of an 

 earthquake before volcanic eruption — it forbodes coming events — 

 and an irruption of sand into the harbor, during some extraordi- 

 nary gale, may be found as destructive to it as an irruption of lava 

 to vineyards and villages." 



I am inclined to agree with Mr. Shanley, in considering the ef- 

 fects of an eastern entrance somewhat problematical, whilst I am 

 induced to believe that both the opinions above quoted are based 

 on very insufficient grounds, as on the one hand the breach has 

 been already closed without artificial aid, and on the other its ef- 



fects have not fulfilled the predictions. As a proof also that by 

 far too much stress has been placed on the effects of lake currents, 

 the breach is now filled to such an extent with sand, that without 

 a previous knowledge of its position one could hardly tell where 

 it had existed. 



That currents exist at the present entrance there is no doubt, 

 and whether attributable to the wind or other natural causes, these 

 currents are doubtless due to occasional differences of level be- 

 tween the waters in the bay and the open lake. If a particular 

 wind exerts a force sufficient to elevate the lake in the vicinity of 

 Toronto a certain number of inches, that rise must of necessity be 

 communicated to the bay through the entrance, and hence a cur- 

 rent of a certain velocity ; and this operation would be reversed on 

 the falling of the water in the lake by a change or fall of the wind. 

 If, therefore, the harbor be provided with two entrances, and if 

 we assume, for the sake of argument, that the sectional area of the 

 second entrance be equal to the first, the current in this case will 

 be equally divided, and its effects, whatever they may be, dimin- 

 ished one-half, and so in proportion to the relative sectional area 

 of the entrances. Thus, then, the effects of currents at the west- 

 ern will be diminished in proportion to the width and depth of the 

 proposed canal at the Isthmus. 



AVe now arrive at the question: What are those effects'? The 

 undoubted tendency of currents in a channel such as the entrance 

 to Toronto Harbour, is to increase its width and depth ; it does not 

 follow that currents in this case have no such tendency, because 

 neither width nor depth have been increased, since they may have 

 been exerted in counteracting other causes as powerful as them- 

 selves ; but I think it will clearly follow that the currents have no 

 effect, or at least no effect of real or practical value, if it can be 

 shown that the channel has been narrowed in width nearly at an 

 equal rate during equal or proportionate times ; for it must be 

 observed that the currents would necessarily increase in velocity, 

 and hence in their scouring effects, the more the opening through 

 which they passed was contracted. Since the end of last century 

 up to 1849, the average rate of the encroachment of the shoal is 

 shewn to have been from 7 to 10 yards per annum ; since then, 

 during 4A years, it has advanced 35 yards, giving an average rate 

 per annum of 8 yards ; and during the last four months, it has 

 advanced at the rate of nearly 12 yards per annum. Thus, then, 

 while the width of the entrance has been diminished, the annual 

 rate of the encroachment of the shoal has actually increased, and 

 the deposit moreover has generally occurred at that point where the 

 current (if it had any effect) would have been the most active. 

 Hence no other conclusion can be come to, than, that there are no 

 undercurrents in the channel, or if there are, they have proved to be 

 of no practical value. The fear, therefore, of destroying or dimin- 

 ishing the effects of currents at the western entrance by the con- 

 struction of a Canal at the isthmus may be entirely laid aside, 

 seeing that there are none. 



We have now to consider whether or not the proposed canal 

 would be self-sustaining ; and. in this respect, I am still of opi- 

 nion that it would not. To place its outer entrance beyond the in- 

 fluence of the beach action, it would bo requisite to extend the 

 piers into deep water, as shewn on the plan ; through course of 

 time, the progressive action being totally arrested, an accumulation 

 would gradually form, more especially on the eastern side of the 

 canal until reaching the extremity of the piers, ultimately rounding 



