Issues: SAV

The Virginia Institute of Marine Science conducts annual surveys using aerial photographs as well as extensive research on submerged aquatic vegetation (SAV) in the Chesapeake Bay. SAV beds provide great habitat for fish and crabs, and are one of the indicators of a healthy estuary.


It is encouraging that the middle section of the Severn River has seen dramatic resurgence of SAV since the early 1990s, and we would like to see that happen in the upper and lower parts of the Severn as well. After Severn SAV had declined to negligible levels in the early 1980’s, the Severn started having mapped SAV beds again in 1994 with a large bed outside the mouth of Asquith Creek that contained both redhead grass and widgeon grass. Severn SAV expanded rapidly from this start and it now has far more SAV than any other rivers on the Lower Western Shore in Maryland, with the Magothy to the north having the second largest amount of SAV in that region.

Water quality data collected by the Severn Riverkeeper shows that the middle part of the river that has most of the SAV in the river also has the clearest water in the river (as measured by Secchi depth). Bay scientists have established a strong link between clear water and SAV growth. Thus, to increase the extent of SAV in the Severn, water clarity in the upper and lower river needs to be improved.

For more information see: