A North Carolina Division of Water Resources plan to develop numeric criteria to address nutrients in the state’s lakes, rivers and estuaries has received approval from the Environmental Protection Agency.
Nutrients such as nitrogen and phosphorus are necessary in waterways to support the food cycle of many aquatic animals. However, excessive levels of nutrients can lead to algal blooms, fish kills, and taste and odor issues that result in increased drinking water treatment costs. Many factors – including water temperature, available light, water depth and how long water stays in one location – can affect the impacts from nutrients to a water body.
The state Division of Water Resources has been working with the public and the EPA to develop a plan that will evaluate nutrient concentrations and take into consideration how nutrients can affect water bodies in different ways, depending on water body characteristics.
The EPA has approved the division’s plan to develop site-specific numeric criteria for each of three water body types: reservoirs and lakes, rivers and streams, and estuaries. After numeric nutrient criteria is developed for a water body representing a type, that criteria will be reviewed to see if it is appropriate for similar types of water bodies on a site-specific basis. In so doing, the criteria will ensure coverage of waters statewide.
The plan presents milestones for development of site-specific criteria for High Rock Lake (reservoir/lake) by 2018, for the Albemarle Sound (estuary) by 2020, and for the Middle Cape Fear River (river/stream) by 2021. Also, the division is assembling a scientific advisory council to help the agency and stakeholders develop a management strategy for addressing nutrients in water bodies throughout North Carolina.
Numeric values for all parameters developed as a part of the plan must protect designated uses such as recreation, drinking water and protection of aquatic life. The numeric values must also provide for the attainment and protection of downstream water quality and use scientifically-defensible methods and analyses.
People can learn more about the plan on the state Division of Water Resources’ website at http://portal.ncdenr.org/web/wq/nutrientcriteria. The web page gives people an opportunity to register for updates and ask questions of staff with the state Division of Water Resources.