The Niagara River drains an area of 254,708 square miles (409,901.5 square kilometers) including the Upper Great Lakes.
The surface area of Lake Erie is 9,910 square miles (25,655 square kilometers). It is the shallowest of all the Great Lakes, averaging 60 feet (18.29m) in depth.
The levels of the Great Lakes vary on an annual basis in relation to season, rainfall, evaporation and runoff. The highest water levels are found in mid-summer and the lowest water levels are found in mid-winter.
The internal time required for an increase supply of water to show its effect upon the level of Lake Erie is approximately 76 days.
The internal time required for a decrease in the supply of water to show its effect upon the level of Lake Erie is approximately 132 days.
The extreme variation of water levels in Lake Erie:
- Greatest variation between 1860 and 1907 was 3.89 feet
- Maximum one year range occurred in 1892 was 2.28 feet
- Minimum one year range occurred in 1895 was .87 feet
- Annual average Lake Erie level variation is 1.56 feet
A variation of in the water level one foot in Lake Erie occurring at Buffalo, New York produces a rate of water flow discharge from Lake Erie into the Niagara River of 20,000 to 25,000 cubic feet per second.
During storms, the water level of Lake Erie at each end may vary as much as fifteen feet. The average annual rainfall in the Great Lakes equals 36 inches. The average annual evaporation rate in the Great Lakes equals 24 inches.
The water discharge of the Niagara River has been determined by measurements taken at the International Railway Bridge at Buffalo/Fort Erie. Measurements began in 1897 by the engineering staff of the U.S. Great Lakes Survey.
The maximum monthly mean water discharge of 257,000 cubic feet per second from Lake Erie occurred in March of 1896. This was equivalent to the entire surface of Lake Erie to a depth of 2.44 feet.
The average discharge of the Niagara River between 1860 and 1907 equaled 212,000 cubic feet of water per second.
Between 1860 and 1907, the greatest excess average for any month occurred in June of 1876 at 45,000 cubic feet of water per second or an increase in water flow of 21% (refer to maximum mean discharge).
The greatest average in excess water flow in any one year occurred in 1876 at 26,000 cubic feet of water per second or an increase of 12%.
The greatest water flow deficiency average for any month was March of 1896 at 43,500 cubic feet of water per seconds or a decrease of 21%.
The greatest water flow deficiency in any year occurred in 1895 at 31,800 cubic feet of water per second or a decrease of 15%.
In September 1999, Lake Erie’s water level was at 571.19 feet (174.10m) above sea level. This was 4.3 inches (11 cm) below the long term average. Lake Erie’s water level was the lowest that has been recorded since 1967.
In February 2000, Lake Erie water level was at 570.08 feet (173.76 m) above sea level. This was 9 inches (23 cm) below the February long term average. Lake Erie’s water level was the lowest that has been recorded since 1967.
Summer of 1999 Great Lakes water levels were 16-24 inches (40-60 cm) below those levels recorded in 1998.
In flow water rates from Lake Erie into the Niagara River have been recorded as follows:
- Sept. 1999 – Feb.2000 = average 173,400 cubic feet per second
- March – August 1999 = average 186,100 cubic feet per second
- The beginning of 1900 – the end of 1989 = average 191,800 cubic feet per second
The water out flow rates of the Niagara River at Queenston are as follows:
- Sept.1999 – Feb.2000 = 184,000 cubic feet per second (greatest one month average = 188,930 cf/s)
- March – August 1999 = 200,660 cubic feet per second (greatest one month average = 207,610 cf/s)
- March – August 1998 = 244,620 cubic feet per second (greatest one month average = 256,000 cf/s)
Lake Erie Precipitation Rates are as follows:
- Sept.1999 – Feb.2000 = 15.8 inches (40.2 cm) of rain
- March – August 1999 = 15.9 inches (40.3 cm) of rain
- From the beginning of 1900 – the end of 1995 = 19.1 inches (48.5 cm) of rain