AUGUST 23

 

 

LOW FLOWS CONTINUE

 

An inch of rain overnight last Sunday brought the Souhegan River back up over the Protected Critical Instream Flow that would require water users and towns along the river to curtail outside watering, but the low flows are still the topic of concern this week. Flow in the upper section of the Souhegan was only 25% of its historic expected flow. This is a slight improvement from two weeks ago when the Souhegan Watershed Association water quality monitoring last took place, but unless more rain continues, the river will shortly return to critical flows.

 

The Merrimack River is ponded by the dam in Lowell up through Nashua and so the level is less evident here, but the flows measured in Manchester are down about 25%. At the time of the tests the flow should have been 1400 cubic feet per second, but it was measured at 1090 cfs.

 

What this means for the E. coli tests is that there is less water to dilute pollution. Ironically heavy rains raise the E. coli levels temporarily – about three days - as pollution from storm drains and river banks gets washed into the rivers. This is especially true after a dry period preceding the rain.

 

This week E. coli levels reflect that. Both the Souhegan and Merrimack Rivers showed high E. coli counts – but for different reasons. The Merrimack is a large river that can dilute pollution that would overwhelm the much smaller Souhegan. Seldom do E. coli counts rise to dangerous levels on the Merrimack, but this week they did. The heavy rain caused the Manchester sewage treatment plant to release raw sewage directly into the river. E. coli counts rose above the 406 dangerous level all the way to Merrimack. But as an indication of the power of dilution, the E. coli count was back down to acceptable levels by the time the river reached Nashua. The E. coli level at the Greeley Park boat ramp measured only 43.

 

The much smaller Souhegan River did not have the very high numbers that showed up on the Merrimack, but the entire river was above the 88 level that indicates clean water. All of the swimming holes tested above the 88 level but most were below 126, which is acceptable swimming for healthy adults. Weston Park at Turkey Hill Bridge in Merrimack was slightly higher at 147, too high for swimming. The Amherst Canoeport at Boston Post Road was too high at 206. All other swimming holes were OK.

 

E. coli monitoring is for human use of the rivers only and a good indicator of pollution levels, 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 www.souheganriver.org.

 

This is the final test for this season. We hope to continue next June to begin our 21st testing season. Tests are all done by Souhegan Watershed Association volunteers who collect samples and data from 30 specific sites on both rivers and transport the samples to wastewater treatment plants in Manchester, Greenville, Milford, Nashua, and Merrimack, where they’re picked up, moved around, and processed by certified lab technicians at the wastewater treatment plants.

 

Here are the results for the test on August 23:

 

E-COLI MONITORING RESULTS FOR TESTS TAKEN ON AUGUST 23, 2016

 

SOUHEGAN RIVER SITES:

 

  1. Billy Ward Pond, Ashburnham  #1 NA; #2 NA

  2. SoR  333  River Road above Water Loom Pond, New Ipswich  9.7

  3. SoR  320  Highbridge, New Ipswich  98.5

  4. SoR  309  Above Greenville Mill Pond, Greenville  112.4

  5. SoR  296  Downtown Greenville upstream of WWTP  84.2

  6. SoR  291  Green Bridge off Rte 31 below Greenville WWTP  119.1

  7. SoR  218  Below the Horseshoe, Wilton   104.6

  8. SoR  210  Downtown Wilton  488.4

  9. SoR  201  Pine Valley Mill, West Milford   NA 

  10. SoR  170  Behind Hayward Field, West Milford   435.2

  11. SoR  155  Souhegan Valley Boys and Girls Club, Milford  138.8

  12. SoR  146  Swing Bridge, Milford  248.9

  13. SoR  133  Riverside Cemetery, Milford   261.3

  14. SoR  130  Behind Lorden Plaza, Milford  114.6

  15. SoR  122  Amherst Country Club  190.4

  16. SoR  116  Amherst Conservation land Fairway Road, Amherst    NA

  17. SoR  095  Boston Post Road Canoeport, Amherst  206.4

  18. SoR  057  Indian Ledges, Merrimack  88.4

  19. SoR  034  Turkey Hill Bridge, Merrimack    146.7

  20. SoR  001  Watson Park, Merrimack    110.6

 

 

MERRIMACK RIVER SITES:

 

1.      Mer  600  Above Amoskeag Dam, Manchester  10.8

2.      Mer  590  Arms Park, Manchester  53.8

3.      Mer  580  Upstream of Piscataquog River, Manchester    NA

4.      Mer  570  Goffs Falls, Litchfield  191.8

5.      Mer  560  Depot Street, Merrimack    547.5

6.      Mer  550  Upstream of Souhegan River, Merrimack   547.5

7.      Mer  540  Thorntons Ferry, Merrimack  365.4

8.      Mer  530  Greeley Park, Nashua  43.1

9.      Mer  520  Taylors Falls Bridge, Nashua   NA

10.  Mer  510  Sagamore Bridge, Hudson  23.3

11.  Mer  500  Pheasant Lane Mall, Hudson    NA

12.  Mer  490  Upstream of Tyngsboro Bridge  39.3

 

                                               

Flow on Upper Souhegan  was 8 CFS and expected flow for that date is 40

Flow on Lower Souhegan  was 31 CFS and historic flow for that date is 42

Flow on Merrimack was 1090 CFS and historic flow for that date is 1400

RAINFALL –1” of rain heavy at times Sunday pm to Monday am.

TEMPS – Souhegan 20C; Merrimack 23C

 

 

 

 

DO MONITORING RESULTS FOR TESTS TAKEN ON AUGUST 23, 2016

 

SOUHEGAN RIVER SITES:

 

  1. Billy Ward Pond, Ashburnham #1 NA; #2 NA

  2. SoR  333  River Road above Water Loom Pond, New Ipswich  7.44

  3. SoR  320  Highbridge, New Ipswich  8.16

  4. SoR  309  Above Greenville Mill Pond, Greenville  8.28

  5. SoR  296  Downtown Greenville upstream of WWTP  8.45

  6. SoR  291  Green Bridge off Rte 31 below Greenville WWTP  8.60

  7. SoR  218  Below the Horseshoe, Wilton   9.66

  8. SoR  210  Downtown Wilton  9.11

  9. SoR  201  Pine Valley Mill, West Milford    NA

  10. SoR  170  Behind Hayward Field, West Milford    7.37

  11. SoR  155  Souhegan Valley Boys and Girls Club, Milford  7.25

  12. SoR  146  Swing Bridge, Milford  6.69

  13. SoR  133  Riverside Cemetery, Milford    7.50

  14. SoR  130  Behind Lorden Plaza, Milford  7.63

  15. SoR  122  Amherst Country Club  6.99

  16. SoR  116  Amherst Conservation land Fairway Road, Amherst    NA

  17. SoR  095  Boston Post Road Canoeport, Amherst  6.53

  18. SoR  057  Indian Ledges, Merrimack  7.83

  19. SoR  034  Turkey Hill Bridge, Merrimack    NA

  20. SoR  001  Watson Park, Merrimack  8.72

 

 

MERRIMACK RIVER SITES:

 

13.  Mer  600  Above Amoskeag Dam, Manchester  NA

14.  Mer  590  Arms Park, Manchester  NA

15.  Mer  580  Upstream of Piscataquog River, Manchester    NA

16.  Mer  570  Goffs Falls, Litchfield  7.75

17.  Mer  560  Depot Street, Merrimack    7.40

18.  Mer  550  Upstream of Souhegan River, Merrimack   7.15

19.  Mer  540  Thorntons Ferry, Merrimack  7.09

20.  Mer  530  Greeley Park, Nashua  7.97

21.  Mer  520  Taylors Falls Bridge, Nashua    NA

22.  Mer  510  Sagamore Bridge, Hudson  8.33

23.  Mer  500  Pheasant Lane Mall, Hudson    NA

24.  Mer  490  Upstream of Tyngsboro Bridge  8.58

 

 

pH RESULTS FOR AUG 23, 2016