Severn Salinity Starts Seasonal Rebound

On gorgeous mornings in September, our intrepid Water Quality Crew were at work tracking conditions in the Severn River, and we’re glad to report there’s a bit of good news.

Salinity is starting to bounce back to normal!

A year ago and through most of the summer, salinity was abnormally low, in the 4 to 5 practical salinity unit (psu) range.

That’s nearly half of the 8 to 15 psu range normally expected in a brackish waterway like the Severn River.

But things started to slowly improve over the summer.

MGO SalinityFor example, at the Traces Hollow Marylanders Grow Oysters reef where our volunteers have been planting baby oysters for the past ten years, salinity on June 6 was 4.37 psu on the bottom where the oysters live.

Salinity remained below 8.0 psu all summer.

It was not until Sept. 5, 2019 that salinity returned to “normal: when our WQ Crew recorded an 8.91 psu reading.

Since early September, salinity throughout the river system has been slowly climbing back to the normal range and breaking well into the 10.0 to 12.0 psu range!

That’s a huge, huge recovery from the collapse of salinity a year ago when salinity bottomed out in the 4 to 5 psu range due to last year’s record-breaking rainfall.

The general lack of rain this summer has helped the salinity rebound.