The highway bridge was dismantled during the summer of 19 50. Livingston County owned one half of the structure, as the center of the river was the boundary line between the two counties. The entire bridge was given to Livingston County as compensation for its demolition by the county’s highway department.
The population of St. Helena dwindled fast after the school was closed in the early 1920’s. The once busy valley had succumbed to the urge of progress and the young folks sought new fields. The river remained a good place for a cool swim on a hot summer day and provided many an occasion for a picnic journey. Many of the young folks of the near-by countryside have pleasant memories of hours spent along the river—and perhaps of Arthur Hopkins melon fields when the family lived across the river on the Orsburn farm.
The long-expected dam was started above Mt. Morris in 1948 and finished in 1951, except for grading and removing buildings and equipment. The last bucket of concrete was poured October 31, 1951, just forty-three months after the project was begun. At the peak of the project. It had employed 550 men.
An article in the Rochester Democrat Chronicle on April 12, 1954, stated that “Miles Freeman, head civilian engineer with the U.S. Army, in charge of operations at the dam, spoke before a county service organization recently and gave some interesting facts:
“With all tributaries of the Genesee River running full banks, and all hollows on the farm land filled with surface water, a five and one-half inch rainfall in twenty-four hours within the watershed of the Mt. Morris dam would bring the water up to the top of the spillway. This would bring it to the same elevation as the foot of the Lower Falls in Letchworth Park. The volume of water would be equivalent to a square city block sixty-three miles high.
“Such a rain fall is not expected but the dam is built to care for such an event.
“Another interesting fact that he stated, was that the dam was built by the Army as a strictly flood control project, yet two nineteen-foot penstocks have been included, for ‘if and when.’ He also stated that the present construction does not provide sufficient water to justify hydroelectric operation, unless three more dams were built near Portageville for flood control.
“Remarking that lime generates heat, he said that the mass of concrete in the dam, in which 1,600,000 tons of rock from LeRoy, and 3,500 carloads of cement, were used, still registers 75 degrees Fahrenheit.
“Large quantities of ice water were used when the concrete was being poured to keep the mixture cool and, therefore, stronger. Three days after pouring, the concrete mass showed a temperature of 115 degrees. Engineers have figured the mass will continue to get stronger for 100 years.
“The dam cost 20 million dollars, which will be liquidated in forty years, with savings from the annual flood damage of $500,000 a year. It is built in fifty-foot sections of monoliths, and once a month eight readings are taken with a ten point plumb bob, to one ten-thousandths of a millimeter. Regular checks are made with a micrometer for contraction and expansion, and as of now, Mr. Freeman stated there is evidence of a change of but 1 16 of an inch in the 1,050 foot structure. . . .”
Source: Anderson, Mildred L. H, and Marian P. Willey. St. Helena, Ghost Town of the Genesee, 1797-1954. Castile, N.Y, 1954. Print.