The Cayuga Lake Defense Fund - Citizen's Guide to Water Quality Hazards Posed by Cornell University's Lake Source Cooling Project

Chapter Two: An Overview of Cornell University's Lake Source Cooling Project

Cornell University currently uses eight giant water chillers to air condition its campus in Ithaca, NY. Seven of those out-moded units rely on ozone-depleting chlorofluorocarbon (CFC) refrigerants whose production and importation has been banned by the U. S. Clean Air Act. One unit does not use CFC refrigerants.

In order to supplement its existing chilled water supply, Cornell proposes to construct a Lake Source Cooling Project to pump up to 46 Million Gallons Per Day of cold water (41F) from a depth of 250 feet near the bottom of Cayuga Lake and pipe that water about two miles to a heat exchange facility located at 983 East Shore Drive near the lake's southern terminus. Part of that site is currently occupied by East Shore Sailing. See Figure One.

The cold lake water would pass continuously through the heat exchange facility, absorbing heat from a five-mile circulating loop that would send chilled water to the campus and return warmed water to be re-chilled. See Figure Two and Figure Three. The heat exchange would raise the lake water temperature as much as 15F.

After passing through heat exchangers, the warmed water, which is also phosphorus- rich, would continuously discharge into the shallow, southern basin of Cayuga Lake through a four foot diameter pipe stretching 500 feet into the lake at a depth of nine to 12 feet. The volume of the discharge would vary on a seasonal basis.

[For another perspective on the locations of LSC cooling pipes in Cayuga Lake, see this map.]

The Phosphorus Data Discrepancy

Ambient levels of total phosphorus in Cayuga Lake have been measured near the proposed Lake Source Cooling intake as well as in the vicinity of the discharge. Based on available information presented in the project's Final Environmental Impact Statement, total phosphorus concentrations already exceed the 20 microgram/liter total phosphorus guidance value adopted by the New York Department of Environmental Conservation.13

The locations of three monitoring locations (P4, S11 and P2) are presented in Figure Four14

The reported monitoring results for total phosphorus measured at the three sites are presented in Table One.15

According to Cornell's Final Environmental Impact Statement, monitoring results from Station P4 or S11 were used to determine that ambient total phosphorus levels in southern Cayuga Lake meet the New York State 20 micrograms/liter total phosphorus guidance value. In fact, the reported concentration of 22.4 micrograms/liter of total phosphorus at Station P4 exceeds the 20 micrograms/liter guidance value. As a result, Cornell's conclusion appears to be erroneous.

Moreover, this section of the document makes no mention of the levels of total phosphorus measured at Station P2 in the shallow portion of Cayuga Lake in the vicinity of the Lake Source Cooling discharge. Those reported concentrations are all above the guidance value: 30.8 micrograms/liter (1994), 23.7 micrograms/liter (1995) and 25.7 micrograms/liter (1996).Those monitoring results uniformly support the conclusion that the ambient concentrations of total phosphorus in southern Cayuga Lake exceed the New York State guidance value of 20 micrograms/liter. The relevant portion of Cornell's analvsis is shown in Figure Five.

For more detailed information about the proposed Lake Source Cooling Project, concerned citizens are invited to review Cornell's Draft and Final Environmental Impact Statements. Copies of these documents are available from Cornell University and the Tompkins County Public Library.

Prepared by the Cayuga Lake Defense Fund (CLDF).
For more information, Call: 275-9054 or 272-7914 or email

CLDF 1998