Triangle Area Water Supply Monitoring Project, North Carolina—Summary of monitoring activities, quality assurance, and data, October 2013–September 2015

Surface-water supplies are important sources of drinking water for residents in the Triangle area of North Carolina, which is located within the upper Cape Fear and Neuse River Basins. Since 1988, the U.S. Geological Survey and a consortium of local governments have tracked water-quality conditions and trends in several of the area’s water-supply lakes and streams. This report summarizes data collected through this cooperative effort, known as the Triangle Area Water Supply Monitoring Project, during October 2013 through September 2014 (water year 2014) and October 2014 through September 2015 (water year 2015). Major findings for this period include:

• More than 5,500 individual measurements of water quality were made at a total of 15 sites—4 in the Neuse River Basin and 11 in the Cape Fear River Basin. Thirty water-quality properties or constituents were measured; State water-quality thresholds exist for 11 of these.
• All observations met State water-quality thresholds for temperature, hardness, chloride, fluoride, sulfate, and nitrate plus nitrite.
• North Carolina water-quality thresholds were exceeded one or more times for dissolved oxygen, dissolved-oxygen percent saturation, pH, turbidity, and chlorophyll a.