AUGUST 12, 2014

 

Here are the results of this week’s tests on the Souhegan and Merrimack Rivers. They are not being distributed widely to the newspapers because of the heavy rains the following day which may have made the results out of date and possiblility misleading to the public. Where we would report satisfactory water quality may have been impacted by the usually higher E. coli levels that we see after such rainstorms. This is the second time this season that we’ve had this situation.

 

For example, a test was done at SoR155 on Wednesday morning and had an E. coli level of 980.4. If the test had been done on Tuesday morning (my mistake, not Tom’s), it might have come in at around 285 (best guess). This illustrates the influence of heavy rains.

 

That being said, there are several interesting items to report. Dissolved oxygen levels are continuing to hold very well. These numbers usually drop during the summer with warmer temperatures and lower flows. We did have a low reading of 6.75 (which is still not bad) at SoR116 on the Souhegan in Amherst, but the rest of the river was around 8, which is excellent. Back in June when we began, the comparable number was around 9.

The Merrimack sites were all in the mid-8s.

 

The Merrimack E. coli levels were all excellent. We look for 88 or less. The highest number on the Merrimack was 46.5 in Nashua. The Merrimack is a real success story as far as E. coli is concerned. It’s become usual to see good numbers on our stretch of the Merrimack. Please note that our program only tests for basic information; there may be other tests that warrant concerns that we have not seen. And there are spots that are problematic. For example, the Beazer site continues to leak creosote into the river right upstream of the Greeley Park (Mer530) site. The Manchester airport continues to wash pollutants into the river from the Cohas Brooks. And, of course, we have CSOs in Manchester and Nashua that release sewage directly into the river when the old single-pipe sewer/drains overwhelm the ability of the wastewater treatment plants – our E. coli results during the last test on July 29 were influenced by CSO releases in Manchester so we had higher numbers on the Merrimack. Each of these problems is being addressed; it takes time and lots of money.

 

Souhegan E. coli numbers are always different; it’s a much smaller river and magnifies the concerns. In general we’ve seen the upper stretch of the Souhegan from the headwaters to Wilton/west Milford as satisfactory. This stretch has a steeper, rocky gradient. The river slows down and meanders back and forth through Milford and Amherst and there are houses and other activities along its banks; the river is shallow and sandy and has eroding sandy banks (which are a whole other problem). Here the E. coli levels build up and where most of the swimming spots are. When the river gets to the Merrimack townline, it cleans up again. There is almost nothing along its banks to contribute to pollution (with several exceptions).

 

That’s the normal, expected results. This week we found a couple of changes. The upper stretch was higher than most of the rest of the river. Except for a dangerously high reading – 461 – at the Swing Bridge in Milford, the middle stretch was not too bad – higher than 88, but not as high as it often is. The swimming holes were a mixed bag. The Horseshoe in Wilton usually tests good; this week it was dangerously high at 461, as high as downtown Milford. The Boston Post Road Canoeport in Amherst was 201, a usual number for that site. Indian Ledges and Watson Park in Merrimack were excellent.

 

Although most of the volunteers reported that the water levels in the Souhegan were ‘low,’ the river is pretty much at its historic level for this date. It may be low, but it’s right where it’s supposed to be.

 

The Merrimack is a different story. The flow and level on the Merrimack is largly determined by the dams on the river. The Amoskeag Dam in Manchester determines the flow and the Pawtucket Dam in Lowell determines the level. The Pawtucket Dam backs up the level all the way to the Naticook Islands in Merrimack. When they lower the Pawtucket Dam to do repairs or replace the boards, the river becomes noticeably lower from Nashua downstream. And maybe that’s what happened this week. Monitors on the lower section of the Merrimack reported the river “the lowest I’ve ever seen it.” Monitors on the upper section reported normal levels. I’ve asked the dam company if they have lowered the boards, but they haven’t responded yet. They are required to notify towns and people along the river when they do this, and they have not done this.

 

Because of the dams, the Merrimack should stay relatively constant.

 

The dams on the Souhegan are also of interest this week. They are all ‘run of the river’ dams; they pass whatever is coming in. The dam that causes Waterloom Pond in New Ipswich has been raised and lowered recently and the dam in Wilton has caused the pond to drop recently. This shouldn’t be happening.

 

As a side note, there are two dams right in the center of Milford that are being studied for removal. They are old mill dams that were left after the mills were long gone for us to clean up now. The studies have been going on for several years and were complicated by upstream hazardous waste sites. It’s finally coming to fruition. There will be a public meeting on September 10th, 6:30 pm, Milford Town Hall to discuss the Draft Feasibility Report for Removal of the McLane and Goldman Dams. The large, three volume report is available on the internet here http://www.milford.nh.gov/departments/community-development/active-projects/dam-feasibility-removal-study

A paper copy of the report is available at the Milford Town Hall and the Wadleigh Memorial Library also.

 

Most of the monitors have been indicating how nice it is having to get out along the Souhegan early in the morning – that is on the pleasant weather mornings. Cardinal flowers are out all along the river. This week lots of minnows were spotted. The usual number of raccoon, deer, bird tracks were reported, but an egret was spotted, pileated woodpecker seen, and a hawk carrying its prey took off.

 

E-COLI MONITORING RESULTS FOR TESTS TAKEN ON AUGUST 12, 2014

 

SOUHEGAN RIVER SITES:

 

  1. Billy Ward Pond, Ashburnham  #1  27.8, #2  <1.0

  2. SoR  333  Water Loom Pond, New Ipswich  88.0

  3. SoR  320  Highbridge, New Ipswich  260.3

  4. SoR  309  Above Greenville Mill Pond, Greenville  178.9

  5. SoR  296  Downtown Greenville upstream of WWTP  261.3

  6. SoR  291  Green Bridge off Rte 31 below Greenville WWTP   238.2

  7. SoR  218  Below the Horseshoe, Wilton   461.1

  8. SoR  210  Downtown Wilton  155.3

  9. SoR  201  Pine Valley Mill, West Milford   71.7

  10. SoR  170  Behind Hayward Field, West Milford   77.1

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

  12. SoR  146  Swing Bridge, Milford  461.1

  13. SoR  133  Riverside Cemetery, Milford   115.3

  14. SoR  130  Behind Lorden Plaza, Milford   NA

  15. SoR  122  Amherst Country Club  186.0

  16. SoR  116  Amherst Conservation land Fairway Road, Amherst    172.2

  17. SoR  095  Boston Post Road Canoeport, Amherst  201.4

  18. Sor   070   Seaverns Bridge, Merrimack   76.7

  19. SoR  057  Indian Ledges, Merrimack  34.5

  20. SoR  034  Turkey Hill Bridge, Merrimack  NA   

  21. SoR  001   Watson Park, DW Hwy, Merrimack   36.8

 

 

MERRIMACK RIVER SITES:

 

1.      Mer  600  Above Amoskeag Dam, Manchester  10.9

2.      Mer  590  Arms Park, Manchester  39.9

3.      Mer  570  Goffs Falls, Litchfield  42.2

4.      Mer  560  Depot Street, Merrimack  45.7

5.      Mer  550  Upstream of Souhegan River, Merrimack   NA

6.      Mer  540  Thorntons Ferry, Merrimack  27.2

7.      Mer  530  Greeley Park, Nashua  NA

8.      Mer  520  Taylors Falls Bridge, Nashua   46.5

9.      Mer  510  Sagamore Bridge, Hudson  21.6

10.  Mer  500  Pheasant Lane Mall, Hudson    NA

11.  Mer  490  Upstream of Tyngsboro Bridge  19.9

 

                                   

                                               

Flow on Upper Souhegan was 18 cubic feet per second; expected flow for that date is 57* cfs. (I don’t believe 57 is correct)

Flow on Lower Souhegan was 47 cubic feet per second; historic flow for that date is 45 cfs.

Flow on Merrimack was 2420 cubic feet per second; historic flow for that date is 1610 cfs.

RAINFALL – none

 

DISSOLVED OXYGEN RESULTS FOR TESTS TAKEN ON AUGUST 12, 2014

 

SOUHEGAN RIVER SITES:

 

  1. Billy Ward Pond, Ashburnham  #1  7.27 , #2  7.94

  2. SoR  333  River Road above Water Loom Pond, New Ipswich  7.60

  3. SoR  320  Highbridge, New Ipswich  8.12

  4. SoR  309  Above Greenville Mill Pond, Greenville  7.77

  5. SoR  296  Downtown Greenville upstream of WWTP  8.59

  6. SoR  291  Green Bridge off Rte 31 below Greenville WWTP   8.47

  7. SoR  218  Below the Horseshoe, Wilton   9.45

  8. SoR  210  Downtown Wilton  9.07

  9. SoR  201  Pine Valley Mill, West Milford   8.59

  10. SoR  170  Behind Hayward Field, West Milford   8.10

  11. SoR  155  Souhegan Valley Boys and Girls Club, Milford  7.49

  12. SoR  146  Swing Bridge, Milford   8.18

  13. SoR  133  Riverside Cemetery, Milford    7.87

  14. SoR  130  Behind Lorden Plaza, Milford  NA

  15. SoR  122  Amherst Country Club  7.50

  16. SoR  116  Amherst Conservation land Fairway Road, Amherst    6.75

  17. SoR  095  Boston Post Road Canoeport, Amherst  7.26

  18. Sor   070   Seaverns Bridge, Merrimack  7.80

  19. SoR  057  Indian Ledges, Merrimack  8.36

  20. SoR  034  Turkey Hill Bridge, Merrimack    NA

  21. SoR  001   Watson Park, DW Hwy, Merrimack  8.75

 

 

 

MERRIMACK RIVER SITES:

 

12.  Mer  600  Above Amoskeag Dam, Manchester  8.21

13.  Mer  590  Arms Park, Manchester  8.45

14.  Mer  570  Goffs Falls, Litchfield   8.10

15.  Mer  560  Depot Street, Merrimack    8.07

16.  Mer  550  Upstream of Souhegan River, Merrimack   NA

17.  Mer  540  Thorntons Ferry, Merrimack  8.19

18.  Mer  530  Greeley Park, Nashua  8.19

19.  Mer  520  Taylors Falls Bridge, Nashua   8.44

20.  Mer  510  Sagamore Bridge, Hudson  8.55

21.  Mer  500  Pheasant Lane Mall, Hudson   NA

22.  Mer  490  Upstream of Tyngsboro Bridge   8.65