

1854] 



VARIATIONS IN THE LEVEL OF THE LAKES. 



129 



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TORONTO, JANUARY, 1854. 



Variations in the Level of the Lakes. 



The annual fluctuations in the level of the water of Lake 

 Ontario appear nearly simultaneous and commensurate with the 

 fluctuations which have been observed to take place in the Upper 

 Lakes. Whatever conclusions are deduced from this phenomenon 

 in Lake Ontario, the same will evidently hold good with respect 

 to Lakes Erie and Huron. Mr. Hall, in his Geology of the 4th 

 District of the State of New York says, that a single individual 

 informed him that about the year 1788 or 1790, the Lakes 

 were as high as in 1838; associating this fact with the observa 

 tions which have been recorded on pages 26 and 62 of this 

 Journal, in the absence of more detailed information, we obtain 

 the following table : 



Minimum LeveI. 

 1819 

 1848 



Maximum Level. 

 1788 or 90 

 1838 

 1853 



Or from Maximum to Minimum 31 years. 



" " 10 



From Minimum to Maximum 19 



It seems scarcely possible to discover any relation between 

 these figures which would indicate periodicity in the occurrence 

 of the fluctuations, or in any recorded phenomena of the kind 

 beyond the rise of the Lakes in the Spring and their fall in the 

 Autumn of the year. We are therefore thrown back upon those 

 enquiries which would lead us to imagine that the annual variations 

 in the levels of the Lakes are due to an unequal amount of rain- 

 fall, and an inconstant degree of evaporation. Whatever apparent 

 regularity may be deduced from observed phenomena appears to 

 be altogether dependent upon those climatic changes which dis- 

 tinguish, in a greater or less degree, every extensive region. 



The chief source of supply is the Niagara River, which joins 

 Lake Ontario with Erie. The quantity of water flowing down 

 this stupendous cataract has been estimated, by Mr. Barrett, at 

 Black-rock. The result of three separate observations, made 

 during the high water of 1838 and 1839, gave 19,500,000 cubic 

 feet, or nearly 600,000 tons per minute.* If we assume 

 20,000,000 cubic feet per minute to represent the maximum quanti- 

 ty passing into Lake Ontario from Lake Erie, the whole volume 

 from that source alone would be sufficient to raise the waters of 

 Lake Ontario 62 feet during one year, or about 2 inches in one 

 day, if there were no outlet, and no waste by evaporation. At 

 the same rate of discharge, Lake Erie would be drained in about 

 two years and four months. The elevation of the waters of the 

 Lakes above their present mean level cannot have taken place to 

 an extent beyond a few feet daring the last geological era. A 

 curious confirmation of this physical fact is given by the Provin- 

 cial Geologist in his Report for the years 1845-6. " Lake 

 Ontario is stated to be about nine feet above the St. Lawrence at 

 the Gallops ; so that any stoppage in the river below the Gallops, 



• Hall's G«olo«ry of the State of New York. 



Vol. II., No. 6, January, 1854. 



which would raise the surface of Ontario beyond twenty-one feet 

 over its present level, would send a broad sheet of its waters, with 

 a violent current, down the valley of the Petite Nation, an acci- 

 dent which, judging from the apparently undisturbed condition of 

 its clay banks, has not happened since the country rose from 

 beneath a tertiary ocean.''' 



There is no reason to suppose that the level of Lake Ontario 

 has risen many inches even, above its present high elevation, for 

 many ages. The existence of an occasional sand bank, support- 

 ing a growth of heavy timber on the shores of both the Upper and 

 Lower Lakes, sufficiently confirm this fact. It is, however, to be 

 remarked that the inroads made by the waters during the last 

 two years have far exceeded those made in 1838. It has been 

 found, as was previously stated, (page 25) that on the Eastern 

 shores of Lake Simcoe, many hundred acres of land are now 

 submerged, and in part denuded of their forest growth by the 

 waters which have covered them during the past summer. 

 Lake Simcoe, an inland body of water, 128 feet above Lake 

 Huron has exhibited precisely the same phenomena as the larger 

 Lakes into which its waters ultimately flow. The same rapid 

 breaking down of its banks and cliff's have constantly occurred 

 during the memory of the oldest settleis on its eastern shores, as 

 are universally witnessed on the clay cliff' shores of Lakes Erie and 

 Ontario. This denuding action, coupled with the detritus of 

 rivers, cannot fail to exercise an influence upon the general level 

 of the bottom of the Lakes during the lapse of years. 



It is well known that a very large portion of the water which 

 falls to the earth in the form of rain or dew becomes again dissi- 

 pated by the process of evaporation. Accurate experiments have 

 been made by competent persons with a view to ascertain the 

 relation existing between rainfall and evaporation, not only from 

 the surface of the soil under different circumstances, but also from 

 the surface of water. 



The following table* shows that the quantity annually passing 

 off from the surface of water mav often equal, and occasionally 

 exceed, the precipitation even in temperate climates. The clear 

 skies and hot sun of Canada West would favor the supposition 

 that the animal results of evaporation from the surface of its great 

 lakes really exceed, in general, those of precipitation. 



Name of place. Evaporation in In. No. of yeart ob. 



London 23.98 3 



Kendal 25.75 3 



Tottenham ... 30 47 



Glasgow i 32.41 



Liverpool 36.73 3 



Paris 38 .__ 



Boston, U. S.f 56 



Ogdensburghj: 49.30 ... 1 



The amount of evaporation from open plains varies from one" 

 half to one-third of the rainfall in this climate. In forest-clad 

 reo'ionsa much greater proportion escapes as drainage. 



The month of May of this year was distinguished not only by 

 the large quantity of rain which fell, but also on account of the 

 number of rainy days, and hence the cloudiness of the sky. In 

 a note attached to the Monthly Meteorological Register of the 

 Provincial Observatory for May, we find the following: — "The 

 depth of rain for this month is much above the average and has 

 been exceeded only in two years, 1844-49; but the number of 

 rainy days is the greatest that has been known throughout the 

 whole series of years, being only equalled in August in 1S44." 

 It must be borne in mind that a cloudy sky of a. few days longer 

 duration than usual during the warm months of the year, will 

 arrest evaporation to such a degree from the surface of water, as 



•Tflumpsou, Inirouucitvti 10 iweteoiwlogy. \hr. Hnle. JJ. H. CUtin. 



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