Over the past decade we see improvements to Sound water quality. A particular focus of conservation efforts has been dissolved oxygen levels, where we are now beginning to see improvements, resulting in large part from upgrades to sewage treatment plants designed to remove nutrients.
Improvements are most notable in the Eastern Narrows and the Western Basin. The Western Narrows remains an area under ecological stress. This region, home to New York City, is disadvantaged by both the heavy development of the land and the low level of tidal exchange with the Atlantic Ocean.