HEPOKTS ON TOKONTO HARBOUR 



11 



40 feet water, (between 300 and 400 feet) thus involving for the 

 construction of effectual groynes east of Lighthouse Point, where 

 the water shallows, an outlay which, if judiciously incurred, would 

 serve to arrest permanently the progress of the sand, give stability 

 to the Peninsula and distribute the expense of future works over a 

 great number of years. It will, doubtless, be becoming in the 

 writer to express more fully the reasons he entertains for the 

 opinion that it is unnecessary to protect the weaker portions of 

 the Peninsula. 



1. Vast bodies of water in the form of waves may break upon 

 it, and over it, without carrying any considerable quantity of 

 materials into the bay, as before noticed. This arises from the 

 very gradual sloping conformation of the shoals lakewards. They 

 may carry away the crests during high water, but they rapidly 

 repair the breach. The sloping character of the shoals being 

 always maintained by the mode of their formation, and waves 

 always breaking when they reach water equal to their own height, 

 their force is destroyed before they reach the shore. During low 

 water levels, the waves break nearer the shore, the re-arranged 

 materials of the beach are then more precipitous, but during this 

 period the breaking waves exert no force on the crests of the 

 beach, because the emerged land due to falling of the Lake 

 protects itself. 



2. It is submitted that we have passed the maximum period of 

 high water ; but, if not, it will occur in June, and before works 

 (supposing they were necessary) could be constructed to protect 

 the weak portions of the beach. It appears quite probable that 

 all period of danger from high water is passed, if we may per- 

 mit ourselves to be guided by the experience of the past. Mr. 

 Hall, in quoting Mr. Higgins, the Topographer to the Geological 

 Survey of Michigan, embodies in a single sentence the probable 

 state of the case. "He considers it probable that the minimum 

 period continues for a considerable period of time, while the 

 maximum continues only for a single year." * (Geo. 4th Dist.) 

 This summer, doubtless, we shall see the Peninsula apparently 

 extending itself in all directions (as it is already doing) by the 

 subsidations of the waters of the Lake, and then will begin to ap- 

 pear and to be thrown up into beaches, the vast accumulations 

 which have been progressing during the last two years of high 

 water from the unprotected naked gullies of the Scarboro' cliffs. 



The answer to the question proposed by the Harbour Commis- 

 sioners respecting "the effects which have been produced or are 

 likely to be produced by the present breach at the eastern ex- 

 tremity of the Bay of Toronto, particularly with reference to the 

 bar at the entrance to the Bay" becomes very materially simplified 

 by recent events. The first event being the natural closing of the 

 breach, the second event the occurrence of another breach of far 

 more imposing dimensions in Ashbridge's Bay. Assuming that 

 the breach had not been closed, it is manifest that the question of its 

 influence upon the bar at the mouth of the Harbour would involve 

 the action of the currents which modify the form of the bar at the 

 mouth. The currents will be noticed hereafter. The question of 

 the breach being prejudicial to the Harbour is also involved in the 

 general question of the influence of the currents, and the necessity 

 for strengthening that portion of the Peninsula where the breach 

 existed has been already discussed. It has also been shown that 

 a permanent opening could not be maintained at that end of the 



* See also Note I. 



Bay without immense outlay, and is consequently not to be recom- 

 mended. The question of "the advisability or otherwise of en- 

 larging the opening between the Harbour and Ashbridge's Bay" 

 is subordinate to the general question of the currents and will be 

 noticed in the sequel. The construction of a permanent opening 

 into the Lake from Ashbridge's Bay, has been shown to be infi- 

 nitely more objectionable than the construction of a canal near 

 the late breach east of the Peninsula Hotel, as involving an enor- 

 mous outlay for the purposes of protecting its mouth and pre- 

 venting, by groynes, the beach roest of it as far as Lighthouse 

 Point from continuing to 'travel' under the influence of the same 

 forces as those which called it into existence. 



It is submitted by the writer that it is quite impossible to sepa- 

 rate the effect of the breach at the east of Toronto Bay on the bar 

 at the mouth of the Harbour from the simultaneous and posterior 

 effect of the breach in Ashbridge's Bay. 



Whatever beneficial or baneful results were produced on the 

 bar by the opening near the Peninsula Hotel, have been entirely 

 obliterated by a power of much greater magnitude acting unceas- 

 ingly during the last five or six weeks, and there seems to be no 

 reason to doubt but that 99 per cent, of the good effects produced 

 by any openings or breaches on the bar, are due to those which 

 have recently occurred in the Lake boundary of Ashbridge's Bay. 

 We can only suppose the effect produced on the bar by the opening 

 near the Peninsula Hotel; it cannot now be measured. Observa- 

 tions made in the autumn might have recorded its effect, if any 

 were noticeable, but since the breach was made in Ashbridge's 

 Bay, those effects have been annihilated, or, at least, so greatly 

 remodelled as no longer to be appreciable. The reasons for this 

 statement are as follows : — ■ 



1st The opening in Ashbridge's Bay, when the writer's attention 

 was first particularly drawn to it, at the beginning of April, was a 

 third of a mile long, and the waves swept through it with terrific 

 violence, producing a current so strong in Ashbridge's Bay towards 

 Toronto Harbour, that all expectation of distinguishing the effects 

 produced at the bar by the opening near Privat's, (then closed,) 

 were entirely dispelled. At another time, towards the end of 

 April, when a few days of calm weather permitted a close exami- 

 nation of the breach, it was found that the waves still breaking 

 over it, although there was very little wind, produced a violent 

 current, which drove the boat in which the writer was seated, with 

 rapidity towards the swamp. A calculation was then made of 

 the amount of water projected into Ashbridge's Bay by the rolling 

 of the waves over the beach. The distance exceeded 1600ft., 

 over which the waves broke. The height of each wave was esti- 

 mated at two feet, the breadth between fifteen and twenty feet. 

 Assuming the length, 1600 feet, the height, one foot, the breadth, 

 ten feet, a quantity of water exceeding 16000 cubic feet would be 

 thrown into Ashbridge's Bay by each system of rolling waves. This 

 occurred, on an average, once in twelve seconds, or five times in a 

 minute, which would give 80,000 cubic feet of water every 

 minute. 



If the Don were 100 feet broad, ten feet deep, and moved at the 

 rate of one foot a second at its mouth, it would throw into the 

 Bay, 60,000 cubic feet a minute ; while the breaking waves over 

 the breach, at Ashbridge's Bay, would, in a comparative calm, 

 throw 80,000 cubic feet at the lowest estimate, into the same 

 general receptacle, during the same time. This number does 



