The impacts of Lake Source Cooling on Cayuga Lake are a central focus of this DEIS. Since 1994, scientists and engineers on the LSC project team have been reviewing historical data, gathering new data, and performing analyses to quantify the magnitude of the potential LSC impacts on the lake ecosystem. We have evaluated potential impacts to the lake's temperature, water chemistry, and aquatic life associated with drawing Cayuga Lake water from a depth of 76 m (approximately 250 ft), adding heat, and returning the water to the lake's upper waters. These efforts have provided us with an understanding of which impacts are of the most significance to the lake, and have enabled us to focus our field and laboratory investigations accordingly.
Our conclusions regarding which potential issues are most critical are reflected in the structure of this DEIS chapter. Environmental Setting (2.3.1) provides an overall introduction to the Cayuga Lake ecosystem, and is followed by subsections that focus on the potential impacts of LSC on six critical issues:
· Thermal Characteristics (2.3.2) examines the effects of drawing cold water from a depth of 76 m (250 ft), adding heat drawn from campus facilities, and returning the warmed water to the shallow southern lake basin through a submerged diffuser. We evaluate effects on lake water temperature, mixing and stratification, and ice cover.
· Phosphorus and Productivity (2.3.3) evaluates the potential impacts of circulating phosphorus (the limiting nutrient for algal production in Cayuga Lake) from the lower waters to the upper waters. The section quantifies potential impacts of the increased phosphorus load to the southern lake basin on algal growth and related water quality characteristics.
· Mysis relicta (2.3.4) looks at the potential for the LSC intake to entrain this small invertebrate species, an important component of the lake's food web. The effectiveness of light as a mitigating measure is evaluated.
· Lake Sediments (2.3.5) examines the water quality and habitat implications of disturbing the lake sediments during construction of the LSC intake and outfall pipelines.
· Zebra and Quagga Mussel Control Measures (2.3.6) addresses potential impacts of methods that will be used to prevent the growth of these exotic molluscs within the LSC system.
· Cayuga Lake Fish Community (2.3.7) discusses the relationship of LSC to fish species in the lake, both in the intake (deep water) and outfall (shallow water) habitats.
