Nitrogen Sensitive Areas

The watersheds

Watershed boundaries follow groundwater, not roads. They cross town lines freely — and the towns either side did not always file the same way. Most of these are designated Nitrogen Sensitive Areas; a few appear only because a town filed over them.

Watershed	Towns	Strongest filing	MassDEP's map calls it
Pleasant Bay	Brewster, Chatham, Harwich, Orleans	Permit granted	Pleasant Bay System
Bass River	Brewster, Dennis, Yarmouth	De Minimis application	Bass River Estuarine System
Herring River	Brewster, Dennis, Harwich	Permit application	Herring River Embayment System
Popponesset Bay	Barnstable, Mashpee, Sandwich	Permit application	Popponesset Bay
Three Bays	Barnstable, Mashpee, Sandwich	Permit application	Three Bays System
Wellfleet Harbor	Eastham, Truro, Wellfleet	Notice of Intent	Wellfleet Harbor Embayment System
Bournes Pond	Falmouth, Mashpee	De Minimis application	Great, Green, and Bournes Pond Embayment Systems
Green Pond	Falmouth, Mashpee	De Minimis application	Great, Green, and Bournes Pond Embayment Systems
Lewis Bay	Barnstable, Yarmouth	Permit application	Lewis Bay Embayment System
Swan Pond River	Brewster, Dennis	De Minimis application	Swan Pond River Embayment System,
Waquoit Bay	Mashpee, Sandwich	Notice of Intent	Waquoit Bay & Eel Pond Embayment System
Allen Harbor	Harwich	Notice of Intent	Allen, Wychmere and Saquatucket Harbors Embayment Systems
Barnstable Harbor	Barnstable	Permit application	not a designated NSA
Centerville River	Barnstable	Permit application	Centerville River - East Bay System
Eel Pond / Waquoit Bay	Falmouth	Notice of Intent	Waquoit Bay & Eel Pond Embayment System
Falmouth Inner Harbor	Falmouth	Notice of Intent	Falmouth Inner Harbor Estuarine System
Fiddlers Cove	Falmouth	Notice of Intent	Fiddlers Cove & Rands Harbor Embayment Systems
Great Pond	Falmouth	Notice of Intent	Great, Green, and Bournes Pond Embayment Systems
Halls Creek	Barnstable	Permit application	not a designated NSA
Little Pond	Falmouth	Notice of Intent	Little Pond System
Megansett Harbor	Falmouth	Notice of Intent	Megansett-Squeteague Harbor Estuarine System
Megansett–Squeteague Harbor	Bourne	Notice of Intent	Megansett-Squeteague Harbor Estuarine System
Oyster Pond	Falmouth	Notice of Intent	Oyster Pond System
Parkers River	Yarmouth	Notice of Intent	Parkers River Embayment System
Phinney's Harbor	Bourne	Notice of Intent	Phinneys Harbor, Eel Pond, & Back River System
Quissett Harbor	Falmouth	Notice of Intent	Quissett Harbor Embayment System
Rands Canal	Falmouth	Notice of Intent	Fiddlers Cove & Rands Harbor Embayment Systems
Rushy Marsh	Barnstable	Permit application	not a designated NSA
Saquatucket Harbor	Harwich	Notice of Intent	Allen, Wychmere and Saquatucket Harbors Embayment Systems
Stage Harbor	Chatham	Notice of Intent	Stage Harbor/Oyster Pond, Sulphur Springs/Bucks Creek, and Taylors Pond/Mill Creek Embayment Systems
Sulfur Springs / Bucks Creek	Chatham	Notice of Intent	Stage Harbor/Oyster Pond, Sulphur Springs/Bucks Creek, and Taylors Pond/Mill Creek Embayment Systems
Taylors Pond / Mill Creek	Chatham	Notice of Intent	Stage Harbor/Oyster Pond, Sulphur Springs/Bucks Creek, and Taylors Pond/Mill Creek Embayment Systems
West Falmouth Harbor	Falmouth	Notice of Intent	West Falmouth Harbor
Wild Harbor	Falmouth	Notice of Intent	Wild Harbor Embayment System
Wychmere Harbor	Harwich	Notice of Intent	Allen, Wychmere and Saquatucket Harbors Embayment Systems

Two sources, two sets of names. This table is built from MassDEP's watershed application table — the record of what each town filed. Whether a property is in a Nitrogen Sensitive Area is decided by a different source: MassDEP's NSA address map. The two do not use the same names, and they do not divide the Cape the same way.

The map adds words the application table leaves off — Embayment System, Estuarine System — and it groups. Chatham's three watersheds are one area on the map. So are Harwich's three. Great, Green and Bournes Ponds are one. The 32 designated rows above correspond to 23 distinct areas on the map.

Not every row here is a designated area. The table this site is built on is titled as though it were a list of designated watersheds. It is not — it is a record of what towns filed, and a town can file over ground that is not designated. Of the 35 rows above, 32 are designated and 3 are not.

MassDEP states that 31 watersheds are designated; we record 32 designated rows across 23 map areas. The remaining difference is spelling — the application table writes some watersheds more than one way, "3 Bays" and "Three Bays", "Swan Pond" and "Swan Pond River". We record the original spelling rather than pick a number quietly.

In the application table, not designated. Barnstable Harbor, Halls Creek, Rushy Marsh appear in MassDEP's watershed application table under Barnstable's permit application, and the filings are recorded here. No designated area appears for any of them on MassDEP's address map, checked 10 August 2026.

On 25 August 2026 MassDEP confirmed this in writing, naming each area: they are not designated Nitrogen Sensitive Areas. Barnstable included them because the town is approaching nitrogen abatement comprehensively, working to town boundaries as well as watershed boundaries. A town may apply for a watershed permit over ground that is not designated.

A filing is not a finding of pollution. MassDEP is explicit on this: a town applying for a watershed permit does not imply the watershed is impaired. The watershed permit is the only mechanism through which MassDEP reviews the effectiveness of alternative approaches to nutrient abatement — permeable reactive barriers, cranberry bog reactors and bog restoration — so a town may file for reasons that have nothing to do with water quality. If you own property in one of these areas, box 4 is your answer on the disclosure form.

Filings: MassDEP watershed application table, 11 June 2026. Map names: MassDEP NSA Address Lookup Map, transcribed 10 August 2026. Non-designation of Barnstable Harbor, Halls Creek, Rushy Marsh confirmed by Andrew Osei, P.E., Wastewater Management — Cape & Islands, MassDEP, 25 August 2026.