Update: 2003 winter sampling

County technicians sample water quality near the North Deep station through 13 inches of ice, March 4, 2003

County technicians sample water quality near the North Deep station through 13 inches of ice, March 4, 2003

Onondaga Lake was covered by ice from January 15, 2003 to March 25, 2003. Average air temperatures for January and February were 18.8°F and 21.7°F, respectively, and by March 13, the ice on the Lake had reached a thickness of 15-inches in the North Basin.

Ice is not as thick in the South Basin because of the inputs of warmer water from tributaries and the Metropolitan Syracuse Wastewater Treatment Plant.

WEP technicians took water samples beneath the ice to get a snapshot of the Lake's water quality when the atmosphere is not in contact with the water. This "on ice" sampling was performed successfully three times last winter.

Samples and in situ (in-place) measurements were taken on February 11 and on March 4 and 13 near the North Deep basin monitoring station (see map below). Last year this sampling could not be performed because of a lack of ice cover during the unusually warm winter. On March 13, 2003, water temperatures throughout the water column were less than 36.5°F.

When winter samples were taken through the ice, dissolved oxygen (DO) was 12 mg/L at the surface and 5.2 mg/L at 18.5 m. Average DO in the October mixing time at 18.4 m was 4.9 mg/L.

Sampling will continue biweekly through November now that the lake is ice-free.

Onondaga County has maintained an ice diary each year since the winter of 1987-1988, noting dates of ice cover and sketching the surface area affected. Observations for the past 3 years are summarized below. Note the variability in the extent and duration of ice cover on the Lake.

Winter Ice first reported Approx. days of ice cover,
North Basin Approx. days of ice cover lakewide
(diary notes > 90%)

99-00 1/17/00 42 28

00-01 12/26/00 66+ 54

01-02 1/8/02 2 2

Source: Onondaga Lake 2001 Annual Report, Onondaga County, NY