Watershed Groups Say E.Coli Levels Back to Normal

Submitted by George May

Although the Merrimack River looks low when you drive over it, there is a lot of water flowing by. All of the local rivers have come down from the very high flows of last week, but they are still considerably above their historic average flow for this time of year. The expected flow for the Merrimack right now is 1800 cubic feet per second; but right now it’s running at 4800 cfs. The flow is high but the elevation is low because the Pawtucket Dam in Lowell is being repaired and the water level has been lowered by five feet. That dam controls the level of the river up to the Nashua area.

As the flows in both the Merrimack and Souhegan Rivers have come down from a very high flow level last Wednesday, so too have the E. coli levels in both rivers. Testing on the Souhegan at Watson Park in Merrimack last week showed dangerous levels of E. coli. Additional testing each day showed the levels not coming down to acceptable levels again until Monday. This swimming spot is being tested twice a week this summer through the joint efforts of the Merrimack River Watershed Council and the Souhegan Watershed Association and the results are posted for everyone in the park.

This week’s tests also showed safe swimming levels pretty much throughout the area. The Merrimack River tested below the safe swimming level at all eleven test sites betweenManchester and Tyngsborough. 

The usual swimming spots on the Souhegan also tested at an acceptable level. An E. coli level under 88 is considered safe for public swimming areas in NH. Watson Park was 73.3 on Monday; the Horseshoe in Wilton was 33.6; Indian Ledges in Merrimack was 53.8; Turkey HillBridge, Merrimack was 61.3.

The upper Souhegan between New Ipswich and Wilton tested at an acceptable level – as it usually does. The middle stretch through Milford and Amherst, where the river slows down and meanders back and forth, the numbers increased to slightly higher than acceptable – as it too usually does. And the lower stretch through Merrimack returned to acceptable levels – as it usually does. 

E. coli levels showed marked increases as it passed through the centers of Greenville, Wiltonand Milford. Levels were reduced after passing through these populated areas. 

Volunteers collect temperatures, E. coli samples, dissolved oxygen samples, observations for water levels, color, odor, and uses at over 30 sites on both rivers every other Tuesdaymorning. The chemical tests are done by certified technicians at the Manchester, Nashua,Merrimack, and Milford wastewater treatment facilities. The results are tabulated and are available at souheganriver.org, Merrimack.org. Anyone interested in helping with the monitoring can contact Karen at swawatertesting@gmail.com.

E-COLI MONITORING RESULTS FOR TESTS TAKEN ON JULY 30, 2013

SOUHEGAN RIVER SITES:

1. Billy Ward Pond, Ashburnham  #1- 9.7, #2- 2.0
2. SoR  333  River Road above Water Loom Pond, New Ipswich  NA
3. SoR  320  Highbridge, New Ipswich  62.7
4. SoR  309  Above Greenville Mill Pond, Greenville  95.9
5. SoR  296  Downtown Greenville upstream of WWTP  178.5
6. SoR  291  Green Bridge off Rte 31 below Greenville WWTP  148.3
7. SoR  218  Below the Horseshoe, Wilton   33.6
8. SoR  210  Downtown Wilton  307.6
9. SoR  201  Pine Valley Mill, West Milford   109.2
10. SoR  170  Behind Hayward Field, West Milford  NA 
11. SoR  155  Souhegan Valley Boys and Girls Club, Milford  204.6
12. SoR  146  Swing Bridge, Milford  235.9
13. SoR  133  Riverside Cemetery, Milford    155.3
14. SoR  130  Behind Lorden Plaza, Milford  137.4
15. SoR  122  Amherst Country Club  160.7
16. SoR  116  Amherst Conservation land Fairway Road, Amherst   172.6
17. SoR  095  Boston Post Road Canoeport, Amherst 107.6 (DUP 129.6)
18. Sor   070   Seaverns Bridge, Merrimack  98.5
19. SoR  057  Indian Ledges, Merrimack  53.8
20. SoR  034  Turkey Hill Bridge, Merrimack   61.3   
21. SoR  001   Watson Park, DW Hwy, Merrimack  73.3*

MERRIMACK RIVER SITES:

1.      Mer  600  Above Amoskeag Dam, Manchester  NA

2.      Mer  590  Arms Park, Manchester    NA

3.      Mer  570  Goffs Falls, Litchfield  27.8

4.      Mer  560  Depot Street, Merrimack    29.2

5.      Mer  550  Upstream of Souhegan River, Merrimack   NA

6.      Mer  540  Thorntons Ferry, Merrimack  25.0

7.      Mer  530  Greeley Park, Nashua  20.1

8.      Mer  520  Taylors Falls Bridge, Nashua   22.8

9.      Mer  510  Sagamore Bridge, Hudson  32.8

10.  Mer  500  Pheasant Lane Mall, Hudson    NA

11.  Mer  490  Upstream of Tyngsboro Bridge  58.1             

• Flow on Upper Souhegan was 35 CFS and expected flow for that date is 23
• Flow on Lower Souhegan was 87 CFS and historic flow for that date is 51
• Flow on Merrimack was 4800 CFS and historic flow for that date is 1800
• RAINFALL -  Sun evening rain. Otherwise clear.
• Temperatures: Souhegan 22 C;  Merrimack 23C