The ponds also appear on maps published in the 19th century and it is at the beginning of that century that accounts begin to appear of occasions on which much larger bodies of water appeared quite rapidly in the area.

In 1810-11 a large lake estimated at some 3000 acres developed.  Reportedly the lake covered a "very valuable sugar work" and other buildings, the tops of some of them still appearing above the water.  Much valuable land was inundated, and several other ponds appeared in the surrounding regions.  On this occasion, as later, canoes and boats were taken to the lake to "afford a pleasant amusement".  Another writer referred to the view of the lake from Walton School:

"… the prospect of such an immense sheet of water, interspersed with small islands covered with palm and other trees, is picturesque and romantic beyond description, and considerably heightened by the abundance of wild fowl skimming about the surface of the lake."

The Vestry of St. Ann sensibly withdrew the parochial taxes on the properties which had suffered from the expansion of the lake.

The next appearance of a large lake occurred in 1863-4.  According to Plummer the high water level disappeared within three days, but another letter-writer in 1917, James A. Marshall, wrote of the lake subsiding “in the course of time”.  Before disappearing the lake had reached depths of up to 40 or 50 feet, a length of some three miles and in places a breadth of about an eighth of a mile.  According to this writer, Mr. Mais, the head master of Walton School obtained a boat, "The Lady of the Lake", for the boys to use. The boys also used to shoot wild duck and other birds around the lake. E. C. Smith in 1934 also had recollections of  this period, though he recalled the water being at its height in 1875 and disappearing by 1881.  On one occasion he remembered, at a place called "Flash’s" where the boys used to bathe, the headmaster was given a ducking by one of his pupils, who afterwards claimed it was a mistake. For Mr. Mais, however, the rising of the lake brought tragedy, as it was to do to others later, when one of his young daughters and her nurse were drowned while bathing in the lake. Marshall also referred to the lake appearing again, though not on as large a scale, in 1874.  He commented of the scene in that year:

"A fine picture might be taken from the top of Mount Diablo looking down on the lake with the driving fog and the sudden appearance of the sun shining on the water....  It was a glorious panorama."