Monday, July 27, 2009

State of Narragansett Bay in Summer '09

It's been a strange summer on the Bay. After a cool, wet spring that had good numbers of adult menhaden and giant striped bass up into the Providence River, it seemed like life in the Upper Bay went through a major transformation around July fourth. Here's a late June striper caught by STB board member Howard Kilguss:

Brown and green algae blooms came and then settled as massive numbers of comb jellies and other ctenophores bloomed and then died off in the past couple of weeks.

The big news is that the bacteria counts are way down in the River and Upper Bay this year, presumably because of the Narragansett Bay Commission's Combined Sewer Overflow (CSO) tunnel project, completed in November of '08. See the e-mail pasted at the bottom from the Buckeye Brook folks about the major drop in bacteria at Conimicut Point this year compared to last.

We just observed the first really low dissolved oxygen levels this past Thursday, July 23rd. Our team found oxygen levels approaching zero in the Seekonk and Upper Providence Rivers, which is not too surprising given all the rain we've had. The mid and lower-Bay seem to be in good shape with regard to oxygen levels, all things considered.

July 2009 saw record rainfall, and correspondingly there were a number of swimming beach and shellfish area closures. The RI Department of health website has a lot of good information on that:

Despite these closures, it's clear that wastewater infrastructure upgrades like the CSO tunnel are paying big dividends already. This is an important lesson for places like Aquidneck Island, South County, and Warwick among other communities facing sewering dilemmas. While there is no single solution for each community, system upgrades do make the water cleaner, and the results can be seen right away. -JT


From Bill Aldrich-

From the RIDOH sampling data, check out below a snapshot of bacteria count decrease from 2008 to 2009 at Conimicut Beach year to date, even given all the rain we have been having.

I think the CSO tunnel is to credit for this, at least in part.

For reference, 10 is the baseline reading and 104 is the reading above which they close beaches to swimming. Red means over that limit, blue means below.

5/20 through 5/31 --- 10, 10, 10, 41 (2008) versus 97, 98 (2009)

6/1 through 6/9 --- 10, 10, 20, 108, 109, 546, 663 (2008) versus 10, 10, 20, 31 (2009)

6/10 through 6/18 --- 10, 31, 145, 146 171 (2008) versus 10, 10, 20, 31, 41, 52, 62, 84 (2009)

6/18 through 6/24 --- 41, 148, 389, 404, 2613, 4884 (2008) versus 10, 10 (2009)