Final River Tests Show Clean Waterways

Hot weather brought lots of people out to enjoy local rivers over the Labor Day weekend.

E. coli tests conducted the day after showed the rivers to be in generally good condition for the week, according to a press statement. This was the last test for this season conducted by over 30 volunteers with the Souhegan Watershed Association. Testing is planned to continue again beginning next June.

The Merrimack River tested clear of E. coli bacteria as it has most all of the summer. Testing over the past 20 years has shown the Merrimack cleaning up for this particular pollution. This week no sites tested were higher than the threshold limit of 88. Near theTyngsborough Bridge the count was a very clean 3. The highest count was seen inManchester, still a very clean 53.

The Souhegan River is tested its entire length, from Ashburnham, MA, to Merrimack, NH. E. coli counts here were higher than the threshold limit as the river passed through centers of town in Greenville, Wilton, and Milford. Also a spike was seen at the Amherst Canoeport at the Amherst Country Club. The E. coli count here jumped up to 727, a dangerous level. It is thought that this was an aberration however due to some localized problem such as flocks of geese or other animals polluting the river. Sites both upstream and downstream were in the 100 level, more acceptable levels.

Swimming holes like the Horseshoe, Indian Ledges, and Watson Park all tested clean. The Amherst Canoeport at Boston Post Road was slightly high at 148, a usual sort of result for this site. This season monitors have seen higher than acceptable levels of bacteria after heavy rainfalls, especially following dry spells. This allows fecal bacteria to be washed into the Souhegan – and other rivers – from animals along the river and from storm drains in populated areas. Contrary to popular opinion, swimming after heavy rains is dirtier than before.

One of the tests that the volunteers collect is for dissolved oxygen (DO). DO levels on both rivers have been excellent this year – and generally excellent for the almost 20 years that the tests have been collected. DO measures the actual health of the river for the plants and animals in and around the river. This test shows that both rivers, which are considered Protected NH Rivers, are quite healthy.

All of the individual data collected for each of the 30 sites along both rivers is available at souheganriver.org. Data from past years and explanations of its significance is also there.

Besides the 30 volunteers, some of whom have adopted their site for many years and have real expertise, the program could not continue without the certified personnel at the wastewater treatment plants in Greenville, Milford, Nashua, Merrimack, and Manchesterwho perform the tests.

SWA is planning to continue this monitoring program beginning again next June. This will be the 20th year of the program that was started with a grant from NH DES and Nashua Regional Planning Commission.

New volunteers are always needed and interested people can contact Karen at swawatertesting@gmail.com for information.

Here are this week’s results. The lower the number the cleaner the river; lower than 88 is excellent.

E-COLI MONITORING RESULTS FOR TESTS TAKEN ON SEPTEMBER 8, 2015

SOUHEGAN RIVER SITES:

1. Billy Ward Pond, Ashburnham #1 21.3, #2 3.0
2. SoR 333 Water Loom Pond, New Ipswich 3.1
3. SoR 320 Highbridge, New Ipswich 65.7
4. SoR 309 Above Greenville Mill Pond, Greenville 93.3
5. SoR 296 Downtown Greenville upstream of WWTP 139.6
6. SoR 291 Green Bridge off Rte 31 below Greenville WWTP 90.9
7. SoR 218 Below the Horseshoe, Wilton 56.3
8. SoR 210 Downtown Wilton NA
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 290.9
12. SoR 146 Swing Bridge, Milford 88.4
13. SoR 133 Riverside Cemetery, Milford 73.8
14. SoR 130 Behind Lorden Plaza, Milford 121.1
15. SoR 122 Amherst Country Club 727.0
16. SoR 116 Amherst Conservation land Fairway Road, Amherst NA
17. SoR 095 Boston Post Road Canoeport, Amherst 148.3
18. Sor 070 Seaverns Bridge, Merrimack 167.06
19. SoR 057 Indian Ledges, Merrimack 59.4
20. SoR 034 Turkey Hill Bridge, Merrimack NA
21. SoR 001 Watson Park, DW Hwy, Merrimack 35.0

MERRIMACK RIVER SITES:

1. Mer 600 Above Amoskeag Dam, Manchester 16.0

2. Mer 590 Arms Park, Manchester 52.0

3. Mer 570 Goffs Falls, Litchfield 52.9

4. Mer 560 Depot Street, Merrimack 28.1

5. Mer 550 Upstream of Souhegan River, Merrimack 27.9

6. Mer 540 Thorntons Ferry, Merrimack 31.3

7. Mer 530 Greeley Park, Nashua NA

8. Mer 520 Taylors Falls Bridge, Nashua 20.1

9. Mer 510 Sagamore Bridge, Hudson 5.2

10. Mer 500 Pheasant Lane Mall, Hudson NA

11. Mer 490 Upstream of Tyngsboro Bridge 3.0

Flow on Upper Souhegan was 12 CFS and expected flow for that date is 23

Flow on Lower Souhegan was 31 CFS and historic flow for that date is 40

Flow on Merrimack was 894 CFS and historic flow for that date is 1390

RAINFALL - Clear, hot, dry

Temperatures: Souhegan 16C; Merrimack 20C