Measures of water quality are the most basic indicators of Bay health. They are key measures of the effectiveness of actions taken to reduce pollution to the Bays.

The six water quality indicators are based on the minimum requirements necessary for reestablishment of bay grasses and healthy dissolved oxygen levels. Each water quality indicator individually is useful to assess changes in the health of the Bays, and collectively they provide a clearer picture of ecological conditions.

The water quality information used in this report comes from more than 30 long-term monitoring sites located in tidal portions of the Bays. Data are collected by both the Department of Natural Resources and Environmental Control and the University of Delaware’s Citizen Monitoring Program.

Overall, water quality in the Inland Bays remains fair to poor, but is improving. Compared to five years ago, nutrient and algae concentrations have improved in some areas. Many places have seen modest long-term positive trends in phosphorus and algae levels.

Water clarity and dissolved oxygen in the Bays, however, have seen no significant long-term improvements. Although seaweed abundance is down compared to the 1990s, blooms still occur. Few areas had water quality conditions that are thought to allow bay grasses to reestablish. Most tributaries and canals continue to have poor water quality.

Water quality improvements are, however, being seen near the Indian River Inlet and in Little Assawoman Bay. With its smaller ratio of land to water, and high water tables, Little Assawoman is likely to be the first Bay to respond to improved watershed management.

Looking Ahead

Until nutrient inputs to the Bays decrease, water quality is likely to remain impaired, particularly in tributaries. Increased tidal flushing through the inlet has likely contributed to better water quality in parts of Indian River and Rehoboth Bays.

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Posted Under: 2016 SotB