WATSON PARK was tested again on Tuesday, July 22. The E. coli levels have dropped to a safe level for swimming once again. The level here was 28.5.

Please note that we use a flag system to show water quality right at the park - a BLUE flag means safe water quality; YELLOW flag means questionable water quality; RED flag means poor water quality.

This was the only site tested on Tuesday; however, one may assume that other sites that were assumed too high last week are again at acceptable levels. Compared to last week's test seen below Watson Park is only at about half of that E. coli level.

All of the sites will be tested again next Tuesday, July 29th, and the results will be posted here when they're available on Wednesday.

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July 15, 2014

 

HEAVY RAINS MAY RAISE E.COLI LEVELS IN RIVERS

 

By the time you read this the E. coli samples taken on Tuesday morning may be invalid. The Souhegan Watershed Association monitors the Souhegan and Merrimack Rivers every other Tuesday during the summer. E. coli levels, however, usually rise after heavy rains preceded by dry conditions – and that was the case on Wednesday, hours after the sampling session.  Because of the warm weather and desirable swimming conditions, SWA took another sample at Watson Park in Merrimack on Wednesday morning. The results will be available Thursday and will be posted at www.souheganriver.org/Monitoring Results. People frequenting any of the popular swimming spots on either river may want to check for concerns.

 

Although the heavy rains may worsen the E. coli levels in the rivers, they should improve the dissolved oxygen levels. Higher oxygen levels are better for the river in general. Fish and plants are healthier. Generally oxygen levels decrease as the summer heats up and the rivers dry up; rainstorms replace the oxygen. Dissolved oxygen levels on both rivers has been excellent this season and generally has not been a problem during the past years that the program has been monitoring.

 

The Tuesday morning E. coli levels were already a concern at one swimming hole on the Souhegan. The Amherst Canoeport at Boston Post Road had a level of 325.5. Any level higher than 88 may indicate bacteria that could cause intestinal problems and ear and eye infections, especially among vulnerable swimmers. Levels between 88 and 126 are satisfactory for most people. Levels above 126 should be avoided. All of the other usual swimming spots on the Souhegan tested at an acceptable level on Tuesday.

 

The upper reaches of the Souhegan from Ashburnham to Wilton had satisfactory readings. Beginning in Downtown Wilton and continuing through Milford and Amherst, the E. coli counts were too high. Over 126. A dangerous level of 435 was reached at the Swing Bridge near the Oval in Milford. Counts came back down through Merrimack, which has mostly rural riverbanks, to 59 at Watson Park near the mouth of the river.

 

The Merrimack River from Manchester to Tyngsborough tested at an acceptable level throughout its length with one exception of 115 at the Sagamore Bridge. None of the other sites tested higher than 88.

 

Both rivers were above average in their flows. Rain since July 4th has been above average and has brought both rivers up. The Souhegan is a small river so is impacted more. Flows on the Souhegan were roughly double their historic averages for this date. The Merrimack was flowing about 40% higher than its historic average. Wednesday’s rains will increase the flows even more.

 

All of the results can be found at nashuatelegraph.com/specialreportsrivertestresults/ or souheganriver.org.

 

The next test will be done on July 29. Volunteers to help with the monitoring are always welcome and can contact swawatertesting@gmail.com for more information.

 

The lab tests are all done by certified personnel at the wastewater treatment plants in Manchester, Milford,  Nashua, and Merrimack. The program is coordinated by the Souhegan Watershed Association.

 

Here are the E. coli results for this week. Numbers lower than 88 are excellent; under 126 are acceptable for most people. Be sure to check the Wednesday reading for Watson Park at www.souheganriver.org if you’re planning on swimming in the Souhegan this week.

 

 

E-COLI MONITORING RESULTS FOR TESTS TAKEN ON JULY 15, 2014

 

SOUHEGAN RIVER SITES:

 

  1. Billy Ward Pond, Ashburnham  #1 9.8,  #2 4.1

  2. SoR  333  River Road above Water Loom Pond, New Ipswich  8.4

  3. SoR  320  Highbridge, New Ipswich  38.3

  4. SoR  309  Above Greenville Mill Pond, Greenville  108.6

  5. SoR  296  Downtown Greenville upstream of WWTP  93.3

  6. SoR  291  Green Bridge off Rte 31 below Greenville WWTP  69.1

  7. SoR  218  Below the Horseshoe, Wilton   77.6

  8. SoR  210  Downtown Wilton  275.5

  9. SoR  201  Pine Valley Mill, West Milford  NA

  10. SoR  170  Behind Hayward Field, West Milford   NA

  11. SoR  155  Souhegan Valley Boys and Girls Club, Milford  248.9

  12. SoR  146  Swing Bridge, Milford  435.2

  13. SoR  133  Riverside Cemetery, Milford   204.6

  14. SoR  130  Behind Lorden Plaza, Milford  298.7

  15. SoR  122  Amherst Country Club  298.7

  16. SoR  116  Amherst Conservation land Fairway Road, Amherst   285.1

  17. SoR  095  Boston Post Road Canoeport, Amherst  325.5

  18. SoR   070   Seaverns Bridge, Merrimack  98.5

  19. SoR  057  Indian Ledges, Merrimack  73.8

  20. SoR  034  Turkey Hill Bridge, Merrimack  71.2   

  21. SoR  001   Watson Park, DW Hwy, Merrimack  58.6

 

 

 

MERRIMACK RIVER SITES:

 

1.      Mer  600  Above Amoskeag Dam, Manchester  12.2

2.      Mer  590  Arms Park, Manchester  51.2

3.      Mer  570  Goffs Falls, Litchfield  44.1

4.      Mer  560  Depot Street, Merrimack   26.2

5.      Mer  550  Upstream of Souhegan River, Merrimack   48.0

6.      Mer  540  Thorntons Ferry, Merrimack  53.8

7.      Mer  530  Greeley Park, Nashua  47.1

8.      Mer  520  Taylors Falls Bridge, Nashua   78.4

9.      Mer  510  Sagamore Bridge, Hudson  114.5

10.  Mer  500  Pheasant Lane Mall, Hudson   NA

11.  Mer  490  Upstream of Tyngsboro Bridge  22.3

 

 

Flow on Upper Souhegan was 97 cubic feet per second; expected flow for that date is 23 cfs.

Flow on Lower Souhegan was 99 cubic feet per second; historic flow for that date is 64 cfs.

Flow on Merrimack was 2690 cubic feet per second; historic flow for that date is 1880 cfs.

RAINFALL – light rain Monday night. Heavy rain after the test.

 

                       

 

DISSOLVED OXYGEN RESULTS FOR TESTS TAKEN ON JULY 15, 2014

 

SOUHEGAN RIVER SITES:

 

  1. Billy Ward Pond, Ashburnham  #1 7.04,  #2 7.30

  2. SoR  333  River Road above Water Loom Pond, New Ipswich  6.84

  3. SoR  320  Highbridge, New Ipswich  7.70

  4. SoR  309  Above Greenville Mill Pond, Greenville  7.50

  5. SoR  296  Downtown Greenville upstream of WWTP  7.95

  6. SoR  291  Green Bridge off Rte 31 below Greenville WWTP  7.91

  7. SoR  218  Below the Horseshoe, Wilton   8.41

  8. SoR  210  Downtown Wilton  8.48

  9. SoR  201  Pine Valley Mill, West Milford   NA

  10. SoR  170  Behind Hayward Field, West Milford  NA   

  11. SoR  155  Souhegan Valley Boys and Girls Club, Milford  7.67

  12. SoR  146  Swing Bridge, Milford  7.76

  13. SoR  133  Riverside Cemetery, Milford   7.83

  14. SoR  130  Behind Lorden Plaza, Milford  7.65

  15. SoR  122  Amherst Country Club  7.68

  16. SoR  116  Amherst Conservation land Fairway Road, Amherst   7.32

  17. SoR  095  Boston Post Road Canoeport, Amherst  7.15

  18. Sor   070   Seaverns Bridge, Merrimack  7.02

  19. SoR  057  Indian Ledges, Merrimack  7.61

  20. SoR  034  Turkey Hill Bridge, Merrimack  7.44   

  21. SoR  001   Watson Park, DW Hwy, Merrimack  8.23

 

 

 

MERRIMACK RIVER SITES:

 

12.  Mer  600  Above Amoskeag Dam, Manchester  7.55

13.  Mer  590  Arms Park, Manchester  8.03

14.  Mer  580  Upstream of Piscataquog River, Manchester   NA

15.  Mer  570  Goffs Falls, Litchfield  7.78

16.  Mer  560  Depot Street, Merrimack   7.63

17.  Mer  550  Upstream of Souhegan River, Merrimack   7.57

18.  Mer  540  Thorntons Ferry, Merrimack  7.35

19.  Mer  530  Greeley Park, Nashua  7.80

20.  Mer  520  Taylors Falls Bridge, Nashua   7.64

21.  Mer  510  Sagamore Bridge, Hudson  7.53

22.  Mer  500  Pheasant Lane Mall, Hudson  NA 

23.  Mer  490  Upstream of Tyngsboro Bridge  7.72

 

                                   

                                               

Flow on Upper Souhegan was 97 cubic feet per second; expected flow for that date is 23 cfs.

Flow on Lower Souhegan was 99 cubic feet per second; historic flow for that date is 64 cfs.

Flow on Merrimack was 2690 cubic feet per second; historic flow for that date is 1880 cfs.

RAINFALL – light rain Monday night. Heavy rain after the test.