Antelope Island is connected with the delta of the Jordan River by a broad, flat sand bar that has been usually submerged but occasionally exposed. It slopes very gently toward the island, and just where it joins it is interrupted by a narrow channel a few inches in depth. For a number of years this bar afforded the means of access to the island, and many persons traversed it. By combining the evidence of such persons it has been practicable to learn the condition of the ford up to the time of its final abandonment. From 1847 to 1850 the bar was dry during the low stage of each winter, and in summer covered by not more than 20 inches of water. Then began a rise which continued until 1855 or 1856. At that time a horseman could with difficulty ford in the winter, but all communication was by boat in summer. Then the water fell for a series of years until in 1860 and 1861 the bar was again dry in winter. The spring of 1862 was marked by an unusual fall of rain and snow, whereby the streams were greatly flooded and the lake surface was raised several feet. In subsequent years the rise continued, until in 1865 the ford became impassable. According to Mr. Miller the present height was attained in about 1868, and there have since occurred only minor fluctuations.
For the purpose of connecting the traditional history as derived from the ford with the systematic record that has now been inaugurated, I visited the bar in company with Mr. Miller on the 19th of October, 1877, and made careful soundings. The features of the ford had been minutely described, and there was no uncertainty as to the identification of the locality. We found 9 feet of water on the sand flat, and 9 feet 6 inches in the little channel at its edge. The examination was completed at 11 a. m.; at 5 p. m. the water stood at 0 feet 10 inches on the Black Rock pillar; and on the following day at 8 a. m. we marked its level at the place where the Farmington pillar now stands, our mark being 2 feet 2 inches above the zero of the pillar.
The Antelope Island bar thus affords a tolerably complete record from 1847 to 1865, but fails to give any later details. It happens, however, that the hiatus is filled at another locality. Stansbury Island is joined to the mainland by a similar bar, which was entirely above water at the time of Captain Stansbury’s survey, and so continued for many years. In 1866, the year following that in which the Antelope bar became unfordable, the water for the first time covered the Stansbury bar, and its subsequent advance and recession have so affected the pursuits of the citizens of Grantsville, who used the island for a winter herd ground, that it will not be difficult to obtain a full record by compiling their forced observations. Since undertaking the inquiry I have had no opportunity to visit that town, but the following facts have been elicited by correspondence. Since the first flooding of the bar the depth of water has never been less than 1 foot, and it has never been so great as to prevent fording in winter. But in the summers of 1872, 1873, and 1874, during the flood stage of the annual tide, there was no access except by boat, and in those years the lake level attained its greatest height. In the spring of 1869 the depth was 4¹⁄₂ feet, and in the autumn of 1877, 2¹⁄₂ feet.
The last item shows that the Stansbury bar is 7 feet higher than the Antelope, and serves to connect the two series of observations.
Diagram showing the rise and fall of Great Salt Lake from 1847 to 1877.
N. S. = Level of new storm line.
O. S. = Level of old storm line.
S. B. = Level of Stansbury Island bar.
A. B. = Level of Antelope Island bar.
Further inquiries will probably render the record more complete and exact, but, as it now stands, all the general features of the fluctuations are clearly indicated. In the accompanying diagram the horizontal spaces represent years, and the vertical, feet. The irregular curve shows the height of the lake in different years. Where it is drawn as a full line the data are definite; the dotted portions are interpolated.
Upon the same diagram are indicated the levels of two storm lines. The upper is the limit of wave action at the present time, and is 3 feet above the winter stage (October, 1877). It is everywhere marked by drift wood, and in many places by a ridge of sand. Above it there is a growth, on all steep shores, of sage and other bushes, but those in immediate proximity are dead, having evidently been killed by the salt spray. Below the line are still standing the stumps of similar bushes, and the same can be found 2 or 3 feet below the surface of the water.
The lower storm line was observed by Captain Stansbury in 1850, and has been described to me by a number of citizens of Utah to whom it was familiar at that time and subsequently. Like the line now visible, it was marked by drift wood, and a growth of bushes, including the sage, extended down to it; but below it there were seen no stumps. Its position is now several feet under water, and it is probable that the advancing waves destroyed most of its features, but the vestiges of the bushy growth above it remain.