Description: For 305(b)/303(d) water quality assessments, NHDES uses assessment units to cover the Great Bay Estuary that are coincident with the shellfish growing areas established by the NHDES Shellfish Program. Great Bay itself consists of seven different assessment units. Nitrogen and eutrophication parameters are logically evaluated utilizing data from larger aggregates of assessment units covering contiguous areas. Eutrophication effects are less localized than the bacteria pollution sources that affect shellfish harvesting. Therefore, NHDES aggregated the assessment units in the Great Bay Estuary into 27 assessment zones. The assessment zones were developed in cooperation with the PREP Technical Advisory Committee. For the Salmon Falls/Piscataqua River, the assessment zones cover both the New Hampshire and Maine sides of the main stem of the river. The river is well mixed and data from both sides of the state line are needed to provide a comprehensive dataset for assessments. However, the assessment determinations made by NHDES only apply to the New Hampshire side of the river. The Maine Department of Environmental Protection makes its own assessment determinations for the Maine side of the Salmon Falls/Piscataqua River.
Copyright Text: The New Hampshire Department of Environmental Services, Watershed Management Bureau, Water Quality Planning Section, should be acknowledged as the data source in products derived from these data.