CLDF - A Citizen's Guide to Water Quality Hazards Posed by Cornell University's Lake Source Cooling Project - Chapter 6

Chapter Six: Uncontrolled Stormwater Runoff

One of the major causes of persistent water pollution problems in Cayuga Lake is uncontrolled stormwater runoff that flows directly into the lake via storm drains or into the lake's various tributaries. Stormwater runoff can cause extensive turbidity problems. It also contains nutrients, including phosphorus, as well as a wide array of chemical contaminants, including heavy metals (such as lead, cadmium, and mercury) and toxic organic chemicals (such as oils, pesticides, PCBs (polychlorinated biphenyls) and pollutants generated by automobile engines). In addition, large quantities of oxygen are required to break down the degradable pollutants found in stormwater.

Even though a comprehensive study has never been conducted to determine the full scope of Cayuga Lake's stormwater runoff problem, the New York State Department of Environmental Conservation determined that runoff pollution is a cause of the water quality use impairments that the agency catalogued in its Priority Waterbodies List.27 Stormwater pollution hazards may be so pervasive in the Cayuga Lake drainage basin, that even proposed multi- million dollar upgrades of local water pollution treatment plants could ultimately prove inadequate to eliminate water quality use impairments. This is because stormwater runoff can contain high levels of phosphorus.

Stormwater Runoff

Stormwater runoff is generated each time it rains, sleets or snows, often in huge quantities. Precipitation falling on streets washes away the various materials that are present on those surfaces and carries them into the storm or municipal sewers that are designed to prevent street flooding as well as naturally occurring bodies of water. Toxic heavy metals, pesticides, industrial organic chemicals and nutrients have all been detected at varying concentrations in stormwater runoff generated in a wide variety of rural, urban and suburban communities. A long list of materials typically found on roadways that can be present in stormwater are found in the printed version of the Guide.28 Examples are metals, antifreeze and oil, to name only three.

While a substantial body of technical information is available regarding the general constituents of stormwater, the quality of stormwater generated by individual communities can vary due to a wide variety of local factors. In general, it is clear that stormwater runoff can cause two types of water pollution. It contains high levels of degradable materials, such as solids and nutrients, that can foster the growth of algae and aquatic plants as well as result in the depletion of oxygen levels in surface waters. Stormwater can also release substantial quantities of toxic chemicals into the environment, particularly over time as persistent pollutant discharges accumulate.

The stormwater generated by the vast majority of communities in America has never been studied to determine its pollution characteristics. Attempts have been made to develop comparisons of the pollution impact of stormwater runoff and various other kinds of wastewater, such as raw and treated sewage. In one major effort, researchers devised a two-pronged assessment of stormwater as a water pollution source. Pollution loads for various cities were monitored for a series of pollution parameters. These findings were compared with the predicted pollution loads of a hypothetical city modeled on the criteria presented in the printed version of the Guide.29

Given the potential for stormwater to degrade water quality in Cayuga Lake, this pollution source should be investigated and assessed as part of any planning efforts related to upgrading the wastewater treatment plants that discharge into Cayuga Lake.

As always, the printed version of this Citizen's Guide contains much more detailed information.

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

CLDF 1998