Chapter 5 Threats
offsite to surface waters. New and expanded mines and quarries may impact high-quality terrestrial uplands, wetlands, or streams. Water quality can be impacted if water from a mining site is discharged before it is appropriately treated to remove pollutants. Instream mining removes sand and gravel directly from a stream bed, resulting in channel instability, altered habitat, increased sedimentation, and increased turbidity (Brown et al. 1998; Meador and Layher 1998) . Instream mining can create pools where riffles once occurred and create headcuts that can continue upstream. These impacts to aquatic habitat can cause changes to aquatic community composition, including local extirpation of species such as freshwater mussels and other rare aquatic species (Hartfield 1993; Watters 2000) . 5.5.6 Nuclear Energy – Anticipated Impacts Nuclear power plants in North Carolina provide electricity for utility customers within our state. They require large volumes of water to ensure that nuclear reactors remain cool; therefore, they are sited near large water bodies or impoundments that are created to supply cooling water. Most impacts associated with nuclear power plants revolve around the facts that they require large amounts of water to cool the nuclear reactors, and the water is considerably warmer than ambient temperature after it has been used for cooling. In North Carolina, nuclear power plants choose between two primary options for discharging heated water: discharge heated water directly into a water body or build a cooling tower that will evaporate and cool water. Duke Energy’s Brunswick Nuclear Plant near Southport transports heated water along a canal until the water is eventually discharged offshore. Duke Energy’s Harris Nuclear Plant cools water with a cooling tower where most water is evaporated. The small amount of collected water that is not evaporated is returned to Harris Reservoir. Returning heated water directly to a water body changes the water quality of the receiving water body, particularly in the area of the discharge, and creates unnaturally warmer water conditions. Other water quality parameters such as DO, salinity, turbidity, pH, and water chemistry parameters may also differ from ambient conditions. Such modifications can affect the species inhabiting the area of the discharge. Use of cooling towers can eliminate the discharge of heated water and deleterious effects on receiving waters. However, water evaporates from cooling towers at a much faster rate than normal and that water is no longer available to contribute to downstream flows. By withdrawing large volumes of water for cooling, aquatic organisms can be impinged or entrained, resulting in injury or death. Impinged organisms can be caught against screens used to prevent transport of larger debris. Continual water pressure against organisms can lead to eventual death or injury. Additionally, some organisms are small enough to pass through screens and will be entrained in the water transported to the nuclear reactors for cooling where they can be subjected to harsh conditions, nearly always leading to death. Water intake
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2025 NC Wildlife Action Plan
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