Second in a 3-Part Series on the Town of Barnstable’s Draft Comprehensive Wastewater Management Plan

Why are Cape waters in so much trouble? The short answer is, Nitrogen. And where does the nitrogen come from? Another short answer. Septic systems… by a mile.
Septic – 78%
Fertilizers – 9%
Stormwater – 8%
Wastewater treatment facilities – 5%

In our last post we showed where Popponesset Bay/ Shoestring Bay fell in the watershed cleanup pecking order.  Here’s our take on why we’re such a low priority for Barnstable.

Nitrogen Allocation from Popponesset Bay Watershed IMA
The towns within the IMA (Barnstable, Sandwich, Mashpee) are each responsible for a portion of the nitrogen removal in the Popponesset Bay Watershed. And the numbers say it all: with Mashpee’s responsibility for 74.5% of nitrogen removal from its wastewater stream, the health of the Bay is in Mashpee’s hands.

Concerns about Shortchanging Shoestring Bay
There are two areas of concern; the wastewater plan requires (a) removing 61% of nitrogen already in the watershed AND (b) mitigating 100% of the flow (future additions) of any new nitrogen into the watershed. That means close to 100% sewering in the Popponesset Bay watershed!

Our Take On This
So the embayment with the worst water quality on the Cape–the waterway that needs 100% sewering–is slated for sewering in, oh, 20 years. Without simultaneous remedial actions, delivered on an ambitious schedule, by Mashpee, Barnstable, and Sandwich, Shoestring Bay won’t come back from the brink of ecosystem failure.

In support of the Barnstable CWMP we suggest that the town:

1. Rethinks its phased plan for sewering infrastructure, prioritizing the most impaired watersheds
2. Considers putting a moratorium on all new Title-5 septic development or expansion in the targeted areas for sewering (within the Popponesset Bay water basin). Outside of those areas, new development within the basin should eliminate Title-5 septic systems in favor of DEP-approved Innovative Advanced (IA) systems that reduce the nitrogen within leach-field effluent to less than 10 milligrams/liter.

Next Post: Big and little ideas for future-proofing our Bays