2016 Parameter Data: Ammonia-Nitrogen, River, Brook and Tributary Sites

Ammonium-nitrogen the most reactive form of nitrogen (N ) present in aquatic systems, and is the preferred form for algal and plant growth. It adheres to soils and sediment, but when dissolved oxygen (DO) is readily available, bacteria quickly oxidize ammonium-N to nitrate- N through a process known as nitrification. Other types of bacteria produce ammonia as a by-product of feeding on dead plant and animal matter, a process called decompostion. Decomposition recycles nutrients while indirectly reducing DO concentrations. At higher temperatures and pH (a measurement of “acidity”) ammonium forms ammonium hydroxide, which is toxic to fish and aquatic life. Waters with low DO and high ammonium hydroxide levels (typically hundreds of parts per billion (ppb) the units URI Watershed Watch reports measurements in) are more toxic than waters with low DO alone. While most sites monitored by URI Watershed Watch have low or below detectable levels of ammonium- nitrogen, many of our deep lakes had periods of quite ammonium-N levels from mid- summer until de-stratification in the fall, usually late September. In addition, high levels of ammonium-nitrogen in surface waters may indicate sewage outfalls, failed septic systems or eutrophication. To learn more see http://cels.uri.edu/docslink/ww/Publications/NitrogenFactsheet.pdf.

Watershed LOCATION MAY JUNE JULY AUG. SEPT. OCT. MEAN Code RIVERS - - (ug/l or ppb) - - Annaquatucket River - A 50 25 <15 35 40 35 32 Belleville @ Railroad Crossing WD @ Rte 216 55 55 25 55 50 20 43 WD Beaver River @ Rte 138 25 <15 55 60 35 70 42 NA Buckeye Brook #1 @ Novelty Rd 170 55 110 155 50 20 93 NA Buckeye Brk #2 @ Lockwood Brk - 110 105 130 - - 115 NA Buckeye Brk #3 @ Warner Brook 95 110 70 105 120 - 100 NA Buckeye Brook #4 @ Mill Cove 115 45 85 115 95 - 91 WD Falls River D - Step Stone Falls 30 110 25 50 <20 25 42 WD Falls River C - Austin Farm Rd. 30 20 <15 30 <20 30 21 WD Falls River A - Twin Bridges 25 20 <15 40 <20 20 20 WD Green Falls River @ Rte 184 (Exit 93) 55 45 <15 35 45 20 35 A Himes River @ Hideaway Lane 25 - 35 35 70 15 36 H HW1A - Scrabbletown Brk @ Falls 35 30 20 35 30 20 28 H HW1B - Scrabbletown @ Rt 4 Bridge 25 30 <15 30 60 20 29 H HW #4 - Davis Memorial 30 - 25 - - - 28 H HW5 - Sandhill Brook (Saw Mill Inlet) 105 125 190 110 120 95 124 H HW6 - Hunt River @ Forge Rd. 40 75 30 - 45 25 43 TH - Upstream 60 55 150 75 155 65 93 TH Moosup River A - Fairbanks 75 25 35 55 90 85 61 WD Pasquisett Brook @ Rte 2 60 115 75 125 50 80 84

NA = Data not available, may be lab error Limit of Detection = 15 or 20 ppb; Mean calculated using half the limit of detection for <##

2016 2016 Parameter Data: Ammonia-Nitrogen, River, Brook and Tributary Sites

Watershed LOCATION MAY JUNE JULY AUG. SEPT. OCT. MEAN Code RIVERS (continued) - - (ug/l or ppb) - - WD @ Rte 91 140 90 98 45 40 70 80 WD Pawcatuck River - Bradford 60 40 <15 45 35 80 45 WD Pawcatuck River - Upstream of Boombridge90 60 20 40 35 20 44 WD Pawtuxet River upstream of Rhodes 70 80 50 65 85 50 67 WD Pendelton Hill Brk @ Grindstone Rd <15 <15 <15 50 - 20 19 WD Queen River @ Mail Rd 25 20 <15 40 35 20 25 WD Queen Tributary - Sherman Brk 20 <15 <15 55 30 40 27 WD Shickasheen Brook @ Rte 2 <15 65 DRY DRY DRY DRY 36 WD Shickasheen Brk @ Miskiania Rd <15 <15 20 40 25 25 21 WD Shickasheen Brk @ Barber P Outlet 20 30 <15 60 30 30 30 WD Shickasheen Brook @ Rte 138 20 110 75 125 - 65 79 WD Shickasheen Brk @ Liberty Lane 30 90 75 45 40 35 53 WD Shunock River @ Hewitt 25 35 30 40 30 <15 28 TE White Horn Brook @ Ministerial 55 95 50 50 35 40 54 WD Wood River @ Switch Rd 25 30 30 35 <20 30 27 WO Woonasquatucket @ Greystone 450 100 35 55 70 25 123 WO Woonasquatucket @ Donigian 110 30 35 180 65 65 81 WO Woonasquatucket - Waterplace Prk 100 65 65 175 290 40 123

Watershed LOCATION MAY JUNE JULY AUG. SEPT. OCT. MEAN

Code TRIBUTARIES (WPWA tribs next page) - - (ug/l or ppb) - - WD Barber - Mud Brook 35 40 105 135 110 40 78 WO Geoville Pond @ Capron Pond - - <15 - 45 50 34 WO Geoville Pond @ Harris Brook - - <15 - 60 50 39 A Secret - Oak Hill East 20 - <15 - - 40 23 A Secret - Trib @ Shore Dr. 25 - 160 - - 25 70 WO Slack's Tributary B (western cove) - 35 - 35 70 30 43 WO Slack's Tributary C (SW cove) - 185 - 85 75 30 94 B Smith & Sayles @ Balcom - <15 <15 - 25 - 13 B Smith & Sayles @ Keech - 50 20 - - - 35 TA Stafford Pond - NE Cove - <15 <15 35 - - 17 WD Watchaug - Perry Healy Brook <15 - <15 - 60 35 28 WO Waterman @ Rte 44 (Nine Foot Brk) <15 - 100 - - 25 44 WO Waterman @ Saw Mill (Cutler Brook) 20 - 40 - - 25 28 Limit of Detection = 15 or 20 ppb; Mean calculated using half the limit of detection for <##

Wood Pawcatuck Watershed Asssociation Tributary Monitoring Sites on the next page

2016 2016 Parameter Data: Ammonia-Nitrogen, River, Brook and Tributary Sites

Watershed LOCATION MAY JUNE JULY AUG. SEPT. OCT. MEAN Code WPWA - TRIBUTARIES - - (ug/l or ppb) - - WD @ Rte 138 40 75 55 40 35 25 45 WD Pawcatuck River below@ Biscuit Kenyon City Rd 50 55 65 75 25 45 53 WD Ind. 175 190 305 1375 365 275 448 WD Pawcatuck River @ Burdickville Rd 60 65 30 40 25 15 39 WD Pawcatuck River @ Potter Hill 40 60 <15 40 <20 35 32 WD Pendelton Hill Brk Rtes 49/216 25 <15 50 55 20 25 30 WD Shunock River @ Rte 49 25 25 <15 45 - 30 27 WD Shunock River @ Rte 184 35 35 - 65 <20 25 34 WD Usquepaugh River @ Rte 2 70 115 138 40 75 55 82 WD White Brook Inlet @ Pine Hill Rd 100 120 185 270 220 155 175

Limit of Detection = 15 or 20 ppb; Mean calculated using half the limit of detection for <## See http://web.uri.edu/watershedwatch/water-quality-factsheets/NitrogenFactsheet.pdf for more information on nitrogen and water quality.

Shunock River in the center of North Stonington Village, taken by Dick Seager (from http://wpwildrivers.org/the- rivers/shunock-river/)

2016