Lots of Water, Moderately Poor E

Lots of Water, Moderately Poor E

August 9

LOW FLOWS

One of the longtime volunteer water quality monitors noted that the SouheganRiver at his site was “as low as I’ve ever seen it.” And most of the monitors at the other 30 sites echoed this by noting the level as “very low.” At the time of the testing on Tuesday morning, flow measured at the gauge in west Milford was 4 cubic feet per second, just 20% of the expected historic flow there. Measured in Merrimack closer to the mouth of the river, the flow was just half of its expected historic flow.

The level of the Merrimack River in the Nashua area is controlled by the dam in Lowell which backs the ponding back to Merrimack and so is less noticeable. But the water level in Manchesterwas below the top of the Amoskeag Dam and flow just downstream was down by one third of its expected flow.

And low flows mean less dilution for any pollution present. Just downstream of the Amoskeag Dam, at ArmsPark, in Manchester the E. coli level was higher than the 88 level the program uses to measureclean water and the level that the state uses for swimming at recognized beaches. “The Merrimack typically tests as clean for E. coli, so that is unusual this week,” said George May, coordinator of the testing program.

The Merrimack cleaned up enough to drop below the 88 level after leaving Manchester and stayed clean to the last site tested in Tyngsborough where the level was only 2.

The SouheganRiver is a much smaller river and so is much more influenced by pollution at low flows. E. coli measured in downtown Wilton reached 770, a level dangerous for human contact. The river improved as it flowed downstream but never reached levels safe for swimming. The SwingBridge in Milford just south of the Oval was 133. The Souhegan becomes a shallow, meandering river through Amherst an area conducive to higher E. coli counts. The E. coli count at the Amherst Canoeport on Boston Post Road was 172, too high for safe swimming. E. coli levels improved to acceptable levels through Merrimack to its confluence with the Merrimack

Other swimming holes tested OK for swimming. The Horseshoe in Wilton was 43, very clean. Indian Ledges in Merrimack was 45. WatsonPark near the mouth of the river where it joins the Merrimack was 31.

SWA no longer posts the E. coli levels at WatsonPark in Merrimack because of a disagreement with the town, who will take over posting. Swimmers can still find the information at the Souhegan Watershed Association Facebook page each Wednesday through Labor Day.

E. coli monitoring is for human use of the rivers only, but SWA also monitors for dissolved oxygen in both rivers. DO levels give the best general indication of the health of the river itself. And monitors found generally good levels of DO again this week. This has been true all season. The rivers are clean for fish and other river creatures and for the environment. More information about DO and the actual readings for each site are listed at

Thirty volunteers, many of whom have been with the program for many years, spend about 20 minutes at the river taking samples and then bring the samples to one of the local wastewater treatment plants in Greenville, Milford, Merrimack, Manchester and Nashua where the samples are processed by licensed professionals.

The next test on August 23 will be the final test for this season.

Here are the results for the test on August 9:

E-COLI MONITORING RESULTS FOR TESTS TAKEN ON AUGUST 9, 2016

SOUHEGAN RIVER SITES:

  1. Billy Ward Pond, Ashburnham #1 NA; #2 NA
  2. SoR 333 River Road above Water Loom Pond, New Ipswich 8.6
  3. SoR 320 Highbridge, New Ipswich 79.4
  4. SoR 309 Above Greenville Mill Pond, Greenville 110
  5. SoR 296 Downtown Greenville upstream of WWTP 79.4
  6. SoR 291 Green Bridge off Rte 31 below Greenville WWTP 125.0
  7. SoR 218 Below the Horseshoe, Wilton 42.8
  8. SoR 210 Downtown Wilton 770.1
  9. SoR 201 PineValley Mill, West Milford NA
  10. SoR 170 Behind Hayward Field, West Milford 248.1
  11. SoR 155 SouheganValley Boys and Girls Club, Milford 139.6
  12. SoR 146 SwingBridge, Milford 133.3
  13. SoR 133 RiversideCemetery, Milford 111.2
  14. SoR 130 BehindLordenPlaza, Milford 93.4
  15. SoR 122 Amherst Country Club 224.7
  16. SoR 116 Amherst Conservation land Fairway Road, Amherst NA
  17. SoR 095 Boston Post Road Canoeport, Amherst 172.3
  18. SoR 057 Indian Ledges, Merrimack 45.0
  19. SoR 034 TurkeyHillBridge, Merrimack 60.2
  20. SoR 001 WatsonPark, Merrimack 30.5

MERRIMACK RIVER SITES:

  1. Mer 600 Above Amoskeag Dam, Manchester 8.4
  2. Mer 590 ArmsPark, Manchester 133.4
  3. Mer 580 Upstream of PiscataquogRiver, Manchester NA
  4. Mer 570 Goffs Falls, Litchfield 25.9
  5. Mer 560 Depot Street, Merrimack 15.6
  6. Mer 550 Upstream of SouheganRiver, Merrimack 9.8
  7. Mer 540 Thorntons Ferry, Merrimack 13.1
  8. Mer 530 GreeleyPark, Nashua 22.8
  9. Mer 520 TaylorsFallsBridge, Nashua 13.1
  10. Mer 510 SagamoreBridge, Hudson 9.8
  11. Mer 500 PheasantLaneMall, Hudson NA
  12. Mer 490 Upstream of TyngsboroBridge 2.0

Flow on Upper Souhegan was 4CFS and expected flow for that date is 22

Flow on Lower Souhegan was 22 CFS and historic flow for that date is 44

Flow on Merrimack was 919 CFS and historic flow for that date is 1460

RAINFALL – spotty showers Sat; otherwise clear

DO MONITORING RESULTS FOR TESTS TAKEN ON AUGUST 9, 2016

SOUHEGAN RIVER SITES:

  1. Billy Ward Pond, Ashburnham #1 NA; #2 NA
  2. SoR 333 River Road above Water Loom Pond, New Ipswich 7.63
  3. SoR 320 Highbridge, New Ipswich 8.04
  4. SoR 309 Above Greenville Mill Pond, Greenville 8.47
  5. SoR 296 Downtown Greenville upstream of WWTP 8.40
  6. SoR 291 Green Bridge off Rte 31 below Greenville WWTP 8.44
  7. SoR 218 Below the Horseshoe, Wilton 9.13
  8. SoR 210 Downtown Wilton 8.53
  9. SoR 201 PineValley Mill, West Milford NA
  10. SoR 170 Behind Hayward Field, West Milford 7.27
  11. SoR 155 SouheganValley Boys and Girls Club, Milford 7.90
  12. SoR 146 SwingBridge, Milford 7.41
  13. SoR 133 RiversideCemetery, Milford 7.13
  14. SoR 130 BehindLordenPlaza, Milford 7.09
  15. SoR 122 Amherst Country Club 6.10
  16. SoR 116 Amherst Conservation land Fairway Road, Amherst NA
  17. SoR 095 Boston Post Road Canoeport, Amherst 6.61
  18. SoR 057 Indian Ledges, Merrimack 7.69
  19. SoR 034 TurkeyHillBridge, Merrimack 8.38
  20. SoR 001 WatsonPark, Merrimack 7.79

MERRIMACK RIVER SITES:

  1. Mer 600 Above Amoskeag Dam, Manchester 8.19
  2. Mer 590 ArmsPark, Manchester 8.16
  3. Mer 580 Upstream of PiscataquogRiver, Manchester NA
  4. Mer 570 Goffs Falls, Litchfield 8.12
  5. Mer 560 Depot Street, Merrimack 7.85
  6. Mer 550 Upstream of SouheganRiver, Merrimack 7.88
  7. Mer 540 Thorntons Ferry, Merrimack 7.79
  8. Mer 530 GreeleyPark, Nashua 8.31
  9. Mer 520 TaylorsFallsBridge, Nashua 8.10
  10. Mer 510 SagamoreBridge, Hudson 8.38
  11. Mer 500 PheasantLaneMall, Hudson NA
  12. Mer 490 Upstream of TyngsboroBridge 8.63
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