JUNE 30th

 

E. COLI LEVELS IN LOCAL RIVERS

 

Rain again raised E. coli levels on both the Merrimack and Souhegan Rivers when tested last Tuesday. This was the third biweekly test this summer and each test was preceded by a heavy rainstorm which rinsed pollution into the rivers. E. coli levels higher than 88 are not acceptable for public swimming areas in NH; all of the tests on both rivers were higher than that.

 

The Merrimack River between Manchester and Tyngsborough, which normally tests very clean for E. coli, had an average reading of 188, well over the recommended level for swimming. Greeley Park this week had a reading of 144.

 

The Souhegan River tested higher in the 300-400 level, well above a safe swimming level. The Horseshoe in Wilton was 276; the Boston Post Road Canoeport in Amherst was 517; Indian Ledges was not tested, Turkey Hill Bridge was 649, and Watson Park was 488. The last three are in Merrimack.

 

Dry weather for three days in a row should bring the pollution levels back down to acceptable swimming levels since that is the life span of the bacteria in the water. But Wednesday’s rain doesn’t bode well for swimming in rivers on the 4th. Ponds generally have less exposure to E. coli pollution after rainstorms and would be a better bet. All public swimming areas require testing for E. coli and would be closed if above the safe level.

 

Swimmers are subject to gastrointestinal problems and ear and eye infections when E. coli levels are higher than 88. The SWA program suggests that levels less than 88 are acceptable for swimming for everyone; less than 126 are probably OK for healthy adults; and levels over 406 are dangerous and should be avoided.

 

Both rivers had very high flows on Tuesday after the rainstorm on the weekend. At least one of the normal sites was not tested because it was too high to monitor safely. The Merrimack has been running at higher than normal flow for the last week.

 

Dissolved oxygen levels in both rivers continued to show healthy conditions. This is the primary test for the actual health of the river itself; and both rivers almost always show healthy levels. The E. coli levels determine how healthy the river is for human use; DO levels determine how healthy it is for the fish, insects, and plant life in the rivers.

 

The program no longer tests for pH since the tests are difficult to interpret, but past testing shows that both rivers are in the normal range for pH - although both show the effects of acid rain after rainstorms.

 

The testing program is done at the same time every other Tuesday morning by approximately 30 volunteers who collect samples and record data at a specific site. The chemical tests are performed by certified personnel in the labs of the wastewater treatment plants in Manchester, Nashua, Milford, and Merrimack. The E. coli tests require 24 hours to grow the bacteria colonies to determine the correct levels.

 

There are still a couple of sites that could use a volunteer monitor. Anyone interested can contact swawatertesting@gmail.com for more information.

 

The Souhegan Watershed Association has been sponsoring this testing program for almost 20 years. Much of that data is on the website at www.souheganriver.org. All of this week’s data is on the site.

 

The next test will be done on July 14; results will be available the following day.

 

Here are this week’s results:

 

E-COLI MONITORING RESULTS FOR TESTS TAKEN ON JUNE 30, 2015

 

SOUHEGAN RIVER SITES:

 

  1. Billy Ward Pond, Ashburnham  #1 10.9;  #2 14.5

  2. SoR  333  Water Loom Pond, New Ipswich  146.7

  3. SoR  320  Highbridge, New Ipswich  307.6

  4. SoR  309  Above Greenville Mill Pond, Greenville  275.5

  5. SoR  296  Downtown Greenville upstream of WWTP  214.3

  6. SoR  291  Green Bridge off Rte 31 below Greenville WWTP   248.1

  7. SoR  218  Below the Horseshoe, Wilton   275.5

  8. SoR  210  Downtown Wilton  435.2

  9. SoR  201  Pine Valley Mill, West Milford   410.6

  10. SoR  170  Behind Hayward Field, West Milford   NA

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

  12. SoR  146  Swing Bridge, Milford  547.5

  13. SoR  133  Riverside Cemetery, Milford   248.9

  14. SoR  130  Behind Lorden Plaza, Milford  NA

  15. SoR  122  Amherst Country Club  378.4

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

  17. SoR  095  Boston Post Road Canoeport, Amherst  517.2

  18. Sor   070   Seaverns Bridge, Merrimack  613.1

  19. SoR  057  Indian Ledges, Merrimack  NA

  20. SoR  034  Turkey Hill Bridge, Merrimack   648.8

  21. SoR  001   Watson Park, DW Hwy, Merrimack  488.4

 

 

MERRIMACK RIVER SITES:

 

1.      Mer  600  Above Amoskeag Dam, Manchester  103.9

2.      Mer  590  Arms Park, Manchester  139.6

3.      Mer  570  Goffs Falls, Litchfield  108.6

4.      Mer  560  Depot Street, Merrimack   NA

5.      Mer  550  Upstream of Souhegan River, Merrimack   307.6

6.      Mer  540  Thorntons Ferry, Merrimack  275.5

7.      Mer  530  Greeley Park, Nashua  143.9

8.      Mer  520  Taylors Falls Bridge, Nashua   248.9

9.      Mer  510  Sagamore Bridge, Hudson  172.2

10.  Mer  500  Pheasant Lane Mall, Hudson   NA

11.  Mer  490  Upstream of Tyngsboro Bridge  187.2

 

                                   

Flow on Upper Souhegan was 264 CFS and expected flow for that date is 49

Flow on Lower Souhegan was 489 CFS and historic flow for that date is 93

Flow on Merrimack was 8380 CFS and historic flow for that date is 2570 (high all week)

RAINFALL -  Heavy rain on Sunday. Otherwise clear.

Temperatures: Souhegan 17C;  Merrimack 19C

 

 

DISSOLVED OXYGEN RESULTS FOR TESTS TAKEN ON JUNE 30, 2015

 

SOUHEGAN RIVER SITES:

 

  1. Billy Ward Pond, Ashburnham  # 1 7.98, #2 8.06

  2. SoR  333  River Road above Water Loom Pond, New Ipswich  7.24

  3. SoR  320  Highbridge, New Ipswich  9.16

  4. SoR  309  Above Greenville Mill Pond, Greenville  9.02

  5. SoR  296  Downtown Greenville upstream of WWTP  9.19

  6. SoR  291  Green Bridge off Rte 31 below Greenville WWTP   9.15

  7. SoR  218  Below the Horseshoe, Wilton   9.59

  8. SoR  210  Downtown Wilton  9.84

  9. SoR  201  Pine Valley Mill, West Milford   9.55

  10. SoR  170  Behind Hayward Field, West Milford    NA

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

  12. SoR  146  Swing Bridge, Milford  9.27

  13. SoR  133  Riverside Cemetery, Milford   9.46

  14. SoR  130  Behind Lorden Plaza, Milford  NA

  15. SoR  122  Amherst Country Club  9.36

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

  17. SoR  095  Boston Post Road Canoeport, Amherst  9.13

  18. Sor   070   Seaverns Bridge, Merrimack  9.03

  19. SoR  057  Indian Ledges, Merrimack  NA

  20. SoR  034  Turkey Hill Bridge, Merrimack  9.19   

  21. SoR  001   Watson Park, DW Hwy, Merrimack  9.89

 

 

MERRIMACK RIVER SITES:

 

12.  Mer  600  Above Amoskeag Dam, Manchester  8.76

13.  Mer  590  Arms Park, Manchester  9.27

14.  Mer  570  Goffs Falls, Litchfield  8.85

15.  Mer  560  Depot Street, Merrimack   NA

16.  Mer  550  Upstream of Souhegan River, Merrimack   9.28

17.  Mer  540  Thorntons Ferry, Merrimack  8.98

18.  Mer  530  Greeley Park, Nashua  NA

19.  Mer  520  Taylors Falls Bridge, Nashua   7.86

20.  Mer  510  Sagamore Bridge, Hudson  8.42

21.  Mer  500  Pheasant Lane Mall, Hudson    NA

22.  Mer  490  Upstream of Tyngsboro Bridge  8.63