REPORTS ON TORONTO HARBOUR. 



27 



them to the detriment of the artificial channel ; to prevent -which 

 contingency the formation of additional groynes from time to time 

 would be necessary ; the construction of which although not in- 

 volving much outlay would always be chargeable to the revenue 

 of the canal. 



I accordingly conclude that in relation to the present Harbour 

 entrance the construction of the canal would be neither beneficial 

 nor detrimental, and that if the preservation of the Bay be alone 

 desired that object can more cheaply and quite as effectually be 

 attained by the much more economical expedient of the Groynes 

 on the Lake beach. These Groynes would probably cost £750 or 

 £1000, whilst the canal could not be constructed for less than 

 £45,000, and inasmuch as the latter may not be considered an 

 engineering necessity, it may be simply viewed in its commercial 

 aspects. Whether the convenience be desirable for the eastern 

 trade of the Port, and if desirable but not being actually necessary, 

 whether the work would be remunerative. Upon this latter point 

 I entertain strong doubts, yet it is sufficient for me in the per- 

 formance of my present duty to express my opinions only on the 

 engineering question, leaving the better qualified body whom I am 

 addressing to determine that of the commercial convenience. 

 There exists no engineering necessity for the canal and its con- 

 struction would result in no advantage beyond that clue to increased 

 facility of communication between this Port and the eastern por- 

 tions of Lake Ontario. 



I now proceed to reply to the next question submitted, viz.: 

 "The advisability, or otherwise of enlarging the opening between 

 the Harbour and Ashbridge's Bay, or of making a permanent 

 opening into the Lake from Ashbridge's Bay." In doing so I 

 shall consider it first in regard to engineering, and secondly in 

 reference to commercial purposes. 



Ashbridge's Bay as commonly known comprises an area of about 

 800 acres, triangular in form with the apex eastward, half of 

 which area may with sufficient accuracy for our present intention 

 be taken as marsh land, the other moiety water of very various 

 depths. It is divided from the Bay of Toronto by a narrow belting 

 of sand and gravel beach, through which two channels have been 

 formed by the waters of the Don delivered into the main bay. 

 Lakeward it is protected and separated from the main Lake by a 

 long narrow sand beach precisely similar in formation to the neck 

 of the Peninsula, and through which the Lake storms make re- 

 peated breaches. To construct proper works of protection to a 

 beach so exposed and so treacherous, and to excavate so large an 

 area of marsh would be a work of such immense cost, as not to be 

 justified except by the most stringent and positive necessity, and 

 under the warranty of certain and indisputable advantages. 



It has been argued that by increasing the body of water within 

 the Bay of Toronto, tJms extended, a strengthened scour at the en- 

 trances would result sufficient to ensure their maintenance through 

 all time. I have already I trust satisfactorily proved that no 

 scour results from the present currents which indeed are entirely 

 superficial, and I think it is undeniable that those currents are 

 mainly created by fluctuations in the Lake levels, traceable to va- 

 riations in the wind and possibly to some more remote and unap- 

 preciable agencies. Now the maximum variation in the Bay 

 water levels hitherto observed, even on extraordinary occasions 

 during any 24 hours (and it is clear that to extend the time would 

 be to diminish the effect) may be taken at five inches, and would give 



800,000 cubic yards of water in the whole Bay due to the rise and 

 effective for scour, but the discharge of this quantity as has been 

 shewn has never retarded the formation of the bar. Excavate 

 Ashbridge's Bay, combine it with the present Harbour, and we 

 should obtain at times of similar variations of level 530,000 

 cubic yards of water additional, or an increase of 66 per cent, on 

 the quantity of water now occasionally flowing through the chan- 

 nel. And this addition can only effect the duration of the current, 

 not its velocity, since the vertical column of water is not increased 

 thereby, and hence also the velocity is not. Moreover, I am in- 

 clined to think we have taken much too favorable a view of the 

 question, in assuming a rise of five inches, I have done so in the 

 absence of more correct knowledge regarding phenomena of which 

 so little, indeed I may say nothing authentic of value is known 

 (for this purpose the self-acting tide guage referred to was in- 

 tended). Although in possession of daily and occasionally more 

 frequent observations reduced to a common datum, the information 

 conveyed thereby is quite insufficient on which to venture an as- 

 sertion, yet from the evidence before me I doubt much if the daily 

 fluctuations exceed one-fourth the amount above stated throughout 

 the year. It is not reasonable in view of the utter insufficiency of 

 the present currents to anticipate that this addition in duration 

 only would yield an effective scour, and accordingly I conclude, 

 that with such an object the combination of Ashbridge's with the 

 Toronto Bay would be valueless. 



Ao-ain, it has been suggested that by such a combination, to- 

 o-ether with an opening or canal to the extreme eastward, a con- 

 stant current would be insured through the entire Bay, and thus 

 the channel kept open by efficient scour. Such an opinion would 

 seem to be based on erroneous observation. The currents still 

 always due and identical with the variations of Lake levels, would 

 still be superficial, and so long as those variations continue to be 

 (and they always will be) unimportant in amount and gradual 

 both in regard to volume and time — so long I believe will all 

 efforts fail to secure an efficient scour. 



I do not, therefore, think it necessary or expedient in an engi- 

 neering view to effect this combination, or to unite these Bays even 

 by the enlargement of the present channel. If the present breach 

 of the Toronto Bay be such as to require protective works, how 

 much more would they be necessary where the existing beach of 

 Ashbridge's Bay is weak and treacherous, and extended in a ten- 

 fold degree. And, moreover, if a channel only were constructed 

 imminent danger would result from the contact of so large an 

 area of swamped land, unless the channel were in fact constructed 

 throughout the length of the marsh as a canal. It might be ex- 

 pedient to direct the water of the Don permanently into Ashbridge's 

 Bay, not indeed that the deposit from that river is so extensive as 

 to be much feared, for the chart shows that the deposition is of 

 slow growth and far less than is popularly imagined, but that as 

 those waters are of no value to the main harbour and might be 

 made an effective conduit for the sewage of the City, the diversion 

 would with such an object be conducive to the health of the City 

 whilst not in a degree detrimental to its harbour. 



If then I am correct in asserting that no advantage would result 

 in engineering point of view by the opening of Ashbridge's Bay, it 

 only remains to be considered whether when regarded commerci- 

 ally it is a desirable work, and I confess that when contemplating 

 the extent of the present Harbour, and the construction of the 



