Souhegan Watershed Association

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2006 E-coli results
2005 Testing Results
2005 E-coli results
2004 Testing Results
2004 E-coli results
2003 Testing Results
2003 E-coli results
2002 Testing Results
2002 E-coli results
2001 Testing Results
2001 DO results
2001 E-coli results
2000 Testing Results
2000 E-coli results
1999 Testing Results
1999 E-coli results
1998 Testing Results
1998 E-coli results
1997 E-coli results
Stream Flow Measurements

Water Testing Results
Summer 2006

Souhegan and Merrimack Rivers

George May's Latest Results Summary

The Souhegan Watershed Association monitors the entire length of the Souhegan River and part of the Merrimack River for their aquatic health. Water samples are tested for pH, phosphorus, dissolved oxygen, temperature, and bacteria. Weather and streamflow information was also recorded when water samples are collected. Previous results, beginning in 1997, are available in reports that can be found in local libraries. Summaries and original results are available here.

This monitoring program is conducted by trained volunteers who believe in cleaner rivers. Financial support for the program comes from donations and special grants. In the past, support has been provided by:

  • A NHDES non-point source pollution grant.
  • Merrimack Valley Paddlers.
  • Amherst Conservation Commission
  • Merrimack Conservation Commission
  • Wilton Conservation Commission
  • Jonathon Rosse
  • Ken ButenhofGeorge May
If you would like to help continue this monitoring effort, please contact George May at 883-3409 or "georgemay (at) adelphia (dot) net" or send a check to SWA, PO Box 1474, Merrimack, NH 03054.

E-Coli Bacteria Counts

Our E-coli samples are prepared and counted by professionals at the local wastewater treatment plants in Greenville, Merrimack, Milford, and Nashua on a volunteer basis. The results are reported as the number of e-coli bacteria colonies observed under a microscope in 100 ml of water. Bacteria levels below 88 colonies per 100 ml. are considered safe for public swimming areas. Anything above that level may cause ear and eye infections, diarrhea or other gastrointestinal problems in a percentage of swimmers. These bacteria numbers being reported are good for only a few days. They do indicate the general health of the river water at a particular moment in time. The next measurement can be considerably different, depending on water level and temperature, and what has recently washed, flowed, or been poured into the river. The current E-coli results this year are available here.

Dissolved Oxygen Measurements

Dissolved oxygen is "breathed" by fish and insects that live in the water. Dissolved Oxygen requirements for different species vary greatly, even if only fish are considered. One of the more sensitive family groups is trout. The lower limit for them is about 5 mg/L (or 5 ppm). The maximum value attainable is called O2 saturation. The concentration of O2 equal to the saturation limit in water increases with DECREASING temperature and INCREASING pressure. At 1 atmosphere pressure and 20 degrees centigrade the concentration of saturated O2 is 9.1 mg/L, while at 1 atmosphere pressure and 25 degrees centigrade O2 is saturated at 8.2 mg/L. The rate of oxygen usage, the rate of oxygenization (turbulence) and the rate of mixing of the different strata of water all contribute to surface oxygen levels. The simplified conclusion is that adequate oxygen levels indicate a healthy, balanced river habitate.


Cumulative 2006 E-Coli Data

September 19th Description
LOCAL RIVERS END SEASON ON UPBEAT TESTS

The Souhegan Watershed Association's water-quality monitoring on the Souhegan and Merrimack Rivers conducted its final bacteria testing for the season on both rivers this past week. The readings on both rivers showed that they are relatively clean. And additional testing on the Nashua River by the Nashua River Watershed Association showed the same - a river relatively clean of bacteria. This is the first time this season that the all three rivers were tested at approximately the same time and under the same conditions. There was relatively little rainfall before any of the tests, which tends to increase the bacteria.

The Merrimack had no bacteria counts in the unacceptable range. The highest number of colonies of bacteria found on the Merrimack was 20 at Arms Park in Manchester. This is well below the 88 colonies that are the acceptable level for public swimming areas. Anything below 88 is considered safe. All of the other sites tested on the Merrimack were even lower that that. At the popular Greeley Park boat ramp in Nashua the count was too low to be observed at the dilution level of the test.

Because of the recent concerns about E. coli found on spinach, some readers may have concerns about any E. coli bacteria showing up in the rivers. But there is a difference. River water is not meant to be ingested. A swimmer may get some water in his mouth, eyes and ears, but he doesn't drink it. This trace amount may still cause intestinal discomfort in particularly susceptible people, but below the 88 level the risk is minimal. Eating or drinking E. coli on contaminated food, however, can lead to severe problems as the spinach scare has pointed out. For example, swimmers can swim in water with an 88 E. coli level, but drinking water from a well cannot have any E. coli and be safe.

The Souhegan River, as usual, had higher E. coli levels than the Merrimack, but it still showed the river to be fairly clean, as it has been most all summer. There were several hot spots - sites that had unacceptable levels of bacteria, but a number of sites that have been of concern in the past were relatively clean this test. The highest reading on the Souhegan was found at the bridge at Rte 122 at the Amherst Country Club. The reading here was 240. Downstream at the conservation land below Beaver Brook in Amherst the count dropped to 180. At the Boston Post Road Canoeport, a popular swimming hole further downstream, the count dropped to 6, one of the lowest counts ever observed at this site. One surprising count showed up in the test just above the Greenville Mill Pond. This site usually has low counts coming from the headwaters area. This week the count was 162, not horribly high, but well above the 88 acceptable level, and a possible indicator that there was an inflow of pollution of some sort in that area shortly before the test date.

The Nashua River had only one unacceptable bacteria count. That was on the Nissitisit River in West Hollis. The reading there was 110. All of the other testing sites on the Nashua mainstem or tributaries in New Hampshire were below the 88 level. The reading on the Nissitisit as it comes out of Lake Potanipo was only 3. The boat ramp at Mine Falls Park was only 38, and this was while a number of boats were out on the pond.

One significant item that probably influences the good bacteria readings that we've seen all this summer has been the substantial flow in all the local rivers. All of the rivers have had considerably higher amounts of water in them all season long. Even this week, after a period of no rain, the Souhegan was flowing at a rate about 50% higher than its historic flow. And this has been true all season, since the May floods.

A full report showing everything that the monitoring program tests for will be published and distributed to watershed libraries and local conservation commissions sometime after the first of the year. This program has been going on for the last ten years using volunteers who care about the environment. The SWA program will start up again next year in June for next season. SWA always needs volunteers willing to give a little of their time to help with the program. People interested can check on the SWA website at www.souhegan.org to sign up to help or get more information.

This program would also not be able to exist if it weren't for the volunteer help that the program gets from the lab personnel at the Milford, Merrimack, and Nashua Wastewater Treatment Plants, who process all of the bacteria samples. Labs used for phosphorus and dissolved oxygen tests are at DES in Concord and the Nashua National Fish Hatchery.

September 5th Description
BACTERIA LEVELS ON LOCAL RIVERS REASONABLE

Although the area received approximately one inch of rain last Sunday, bacteria levels did not increase significantly in the Merrimack and Souhegan Rivers according to Ken Butenhof, coordinator of the water quality monitoring program conducted by the Souhegan Watershed Association and the Merrimack River Local Advisory Committee. "Generally both rivers tested a bit better than expected for this time of year," said Butenhof. Every one of the sites on the Merrimack River between Manchester and the Tyngsborough Bridge tested below the 88 colonies of bacteria per 100 liters of water that is considered the safe limit for public swimming. This has been true for testing along the Merrimack for the last couple of years according to Butenhof. "We are seeing a definite cleanup of the bacteria in the Merrimack", he said. "This river is a poster-child for the Clean Water Act. It wasn't that long ago that it was a virtual sewer, and now it's clean enough to swim in."

The Souhegan River had readings higher than the acceptable 88 limit starting at the dam along Rte 101 on the Wilton/Milford town line. This dam has been drawn down to accommodate Wilton town workers putting a new water main across the river just upstream. This disturbance may have increased the bacteria and sedimentation at sites immediately downstream. All of the downstream sites through Milford, Amherst, and Merrimack exceeded the 88 limit with two interesting exceptions. The site at the Boston Post Road Canoeport in Amherst, a locally popular swimming hole, had a reading of only 6. This is unusual since this site usually tests higher than the surrounding sites and almost always higher than the acceptable limit. The other exceptional site was the site behind Lorden Plaza in Milford. This site is just downstream of the Milford Wastewater Treatment Plant, which discharges treated effluent into the Souhegan just upstream of this site. The reading here was only 24 colonies of bacteria.

Both rivers continued to have substantially above average flow for this time of year. This has been true since the heavy rain conditions back in the spring. Flow on the Souhegan was 197 cubic feet per second, five times higher than the historical average of 38 cfs for this date. The Merrimack was flowing at 2800 cfs, twice its historical average. High groundwater levels have kept all the rain in the rivers this summer.

Souhegan Watershed Association and Merrimack River LAC volunteers test the Souhegan and Merrimack Rivers for bacteria, dissolved oxygen, pH, phosphorus, temperature, and turbidity biweekly from June through September. The E. coli tests are performed at the Milford, Merrimack, and Nashua Wastewater Treatment Facilities.

The next tests will be done on Tuesday, August 19. Past E. coli results are available on the SWA website at www.souhegan.org. Reports of the full testing program for past years are available at watershed libraries.


August 22nd Description
BACTERIA LEVELS LEAP

E. coli bacteria levels on the Merrimack and Souhegan Rivers increased substantially to unhealthy levels not seen so far this summer. Of the 15 sites tested on the Souhegan River, only two were considered safe for swimming. The Merrimack, a much larger river, fared slightly better.

Bacteria counts normally increase as the water temperatures increase and the volume of flow decreases during the summer, but a substantial rainstorm on Sunday, two days before the test, brought bacteria to unhealthy levels throughout the watershed. Two of the most popular swimming holes on the Souhegan had widely differing results. The Horseshoe in Wilton had the best counts on the river - 24. The Boston Post Road Canoeport in Amherst had the worst - 666. The state considers a count higher than 88 unsafe for public swimming areas. Susceptible swimmers could experience ear and eye infections and intestinal distress as the counts increase beyond 88. The only other site tested on the Souhegan that was considered safe was at the very beginning of the river in New Ipswich.

The Merrimack River between Manchester and Tyngesborough had three sites that were below the 88 level and four that were above. The highest count on the Merrimack, however, was only 176, still a concern but not dangerously high. The Merrimack River normally tests quite clean of E. coli bacteria except during very heavy rainstorms when stormdrains overwhelm the wastewater treatment plants and raw sewage is discharged directly to the river. There are 26 discharge pipes in Manchester and eight in Nashua that can put raw sewage directly into the river. Further downstream Lowell, Lawrence, and Haverhill also have discharge pipes that can pollute the river. All five communities are supposed to be working on plans to prevent this from happening according to the EPA.

Flow on both rivers continued to be much higher than they should be at this time of year. This should tend to reduce the bacteria counts as there is more water to dilute the pollution. The flow on the Souhegan was 168 cubic feet per second. The flow on the Merrimack was 3510 CFS. Their historical averages for this time of year is 41 and 1500 respectively. Both of the rivers have exceeded their expected flows all summer long. However, any rain storms have brought the rivers up very quickly as the ground has not been dry enough to absorb extra water. This allows pollution to go directly into the rivers instead of being retained on the land.

The E. coli bacteria generally live for about three days. These tests give a general picture of the health of the river but are not valid after three days. Our next test will be done on September 5.

Souhegan Watershed Association and Merrimack River Local Advisory Committee volunteers test the Souhegan and Merrimack for bacteria, dissolved oxygen, pH, phosphorus, temperature, and turbidity biweekly from June through September. The E. coli tests are performed at the Milford, Merrimack, and Nashua Wastewater Treatment Facilities. Past E. coli results are available on the SWA website at www.souhegan.org. Reports of the full testing program for past years are available at watershed libraries.


August 8th Description
WARMER WEATHER RAISES BACTERIA LEVELS
ON LOCAL RIVERS

E. coli bacteria levels on the Souhegan And Merrimack Rivers increased from levels measured just two weeks ago but are still at no level for concern for swimmers, boaters, or fishermen. One exception to this is the upper, free-flowing stretch of the Merrimack River between Manchester and Reeds Ferry in Merrimack. Two weeks ago the bacteria level was very high on this stretch of the river - probably a result of rainstorms further upstream that were still influencing the river. This week this upper stretch of the Merrimack tested quite clean - as it does most of the time.

The flow on both rivers is still more than double what is historically expected for this time of year. The Souhegan was running at 95 cubic feet per second at the time of the test. Historically it should be at 41 CFS. The Merrimack was running at 3740 CFS at the time of the test. At 7 gallons per cubic foot, that's slightly less than 30,000 gallons per second. The rivers are still draining the heavy rains experienced throughout the watershed earlier in the summer.

The warmer temperatures as the summer progresses normally bring higher bacteria counts in rivers and lakes according to George May, president of the Souhegan Watershed Association, which is responsible for the all-volunteer monitoring program. "Things still look pretty good for both rivers however," he commented.

Two readings on the Souhegan River were higher than acceptable. The river in Milford between the Souhegan Valley Boys and Girls Club and Keyes Field had 246 colonies of bacteria in 100 milliliters of water, and the stretch of river in Amherst downstream of Beaver Brook and across from the Amherst Country Club had 233 colonies of bacteria per 100 mL. The acceptable level for public swimming is 88. Neither of these two areas is used for swimming, but the tests indicate the overall health of the river. The Milford site was also one of the least acceptable two weeks ago also.

All of the usual swimming holes on both the Souhegan and Merrimack tested OK. All tested below the 88 level except for two. Both the Boston Post Road Canoeport in Amherst and Indian Ledges in Merrimack tested in the 130-140 range, slightly higher than acceptable. Bacteria at this level could cause ear and eye infections and intestinal discomfort in a small number of susceptible swimmers. The swimming hole near the Turkey Hill Bridge in Merrimack tested at only 6, a very clean number.

Two of the tributaries on the Souhegan, Billy Ward Pond in Ashburnham, MA, and Purgatory Brook in Lyndeborough/Mont Vernon, have tested very clean all season. Neither site has shown any discernable bacteria. The test site for Purgatory Brook is at Purgatory Falls, not at the mouth of the brook.

As usual, the Merrimack River had very low bacteria counts. None of the sites between Manchester and Tyngsborough even approached the unacceptable 88 limit. An average for the whole river segment was only 23. Both rivers, but especially the Merrimack, have shown signs of cleaning up substantially since the passage of the Clean Water Act and the requirements that pollution be kept out of all rivers.

Souhegan Watershed Association and Merrimack River LAC volunteers test the Souhegan and Merrimack for bacteria, dissolved oxygen, pH, phosphorus, temperature, and turbidity biweekly from June through September. The E. coli tests are performed at the Milford, Merrimack, and Nashua Wastewater Treatment Facilities. The next tests will be done on Tuesday, August 15. Monthly tests are done on the Nashua River. The next test there will be on August 19. Past E. coli results are available on the SWA website at www.souhegan.org. Reports of the full testing program for past years are available at watershed libraries.


July 25th Description
RAINS INFLUENCE BACTERIA LEVELS ON LOCAL RIVERS

Recent E. coli tests on the Souhegan, Merrimack, and Nashua Rivers demonstrate the effect of rainfall on the bacteria levels in local waterbodies. All but one site on the Nashua River and its tributaries in NH tested well above the 88 level that is the safe swimming/bathing level. The one site that tested OK was on the Nissitisit River in Brookline, one of the main tributaries to the Nashua River. However, all of the Nashua River sites were tested on July 15 following a heavy rainstorm on July 12. The bacteria generally live for a three-day period and so it is thought that the high counts were influenced by all the bacteria that were washed into the rivers from riverbanks, storm drains, and road runoff. For example, the monitor noted that there was evidence that people were feeding the ducks at the boat ramp in Mine Falls Park in Nashua; the bacteria count there was almost 300. Another monitor noted horse manure near another one of the test sites. All of this gets washed into the water and raises the bacteria levels.

Tests on the Souhegan and Merrimack were done on July 25 and were not heavily influenced by any rainstorms. Generally all of the bacteria tests on the Souhegan River came out OK. Swimming holes at the Horseshoe in Wilton tested at 80, completely safe for swimming, and at the Boston Post Road Canoeport in Amherst at 120, slightly above the 88 safe level. The highest level of bacteria was found behind Keyes Field in Milford across from the Boys and Girls Club. That level was 128, still a fairly low number. Several sites in the Souhegan headwaters or on tributaries had bacteria levels too low to count. Billy Ward Pond in the headwaters to the South Branch of the Souhegan in Ashburnham, MA; Purgatory Brook in Lyndeborough/Mont Vernon; and upstream of the Greenville Mill Pond on the mainstem of the Souhegan all tested at less than 2 colonies of bacteria in 100mL of water, the lowest ability of the test. The site that was shown in the front-page photo in Wednesday's Telegraph tested at 100, slightly higher than acceptable.

The Merrimack River between Manchester and Tyngsborough showed varied results. The upper stretch from the Amoskeag Dam in Manchester to the Reeds Ferry boat ramp at Depot Street in Merrimack tested very high, from 250-350, well over the safe swimming level. Below this stretch the river tested quite clean, 20-25. The tests reflect the different character of the Merrimack between Manchester and Tyngsborough. The stretch that was not acceptable is a free-flowing stretch that is heavily influenced by Manchester. The stretch that was acceptable is ponded up by the dam in Lowell and is mostly slower moving flatwater. The Merrimack is still very high from spring rains and has a very high flow below Manchester. On Tuesday the flow rate was 11,000 cubic feet per second; at this time of the year it should be around 1500 cfs.

Souhegan Watershed Association volunteers test the Souhegan and Merrimack for bacteria, dissolved oxygen, pH, phosphorus, temperature, and turbidity biweekly from June through September. The E. coli tests are performed at the Milford, Merrimack, and Nashua Wastewater Treatment Facilities. The next tests will be done on Tuesday, August 8. Monthly tests are done on the Nashua River. The next test there will be on August 19. Past E. coli results are available on the SWA website at www.souhegan.org. Reports of the full testing program for past years are available at watershed libraries.


July 11th Description
E. COLI LEVELS ON LOCAL RIVERS GENERALLY GOOD

E. coli testing done last Tuesday by the Souhegan Watershed Association and the Lower Merrimack River Local Advisory Committee show very clean water on the upper half of the Souhegan River and on the entire stretch of the Merrimack River between Manchester and Tyngsborough. The lower half of the Souhegan River through Milford, Amherst and Merrimack did not do as well.

The testing program looks for an E. coli count of 88 or less that would be absolutely safe for swimming. Water testing above this level could cause diarrhea, eye and ear infections, and other medical problems for some percentage of swimmers or others in direct contact with the water. As the E. coli count increases, so does the percentage of swimmers who would experience illnesses. The E. coli counts in the Milford and Amherst stretch of the Souhegan tested in the 200 range. This is not terribly high, but it does indicate that there is a danger for swimming in this area. The Amherst Canoeport near Souhegan High School is a popular summer swimming hole. The E. coli count here was 190. There were no tests done downstream on the Souhegan River as it goes through Merrimack this week, but prudence would suggest that the E. coli counts there may be high as well.

The Merrimack River this week showed some of the lowest E. coli levels seen in the ten years that the LAC has been testing the river according to George May, one of the program coordinators. In many cases the water showed no E. coli at all and is expressed as "less than 1 or 2," the lowest limit of the particular test. "The low numbers on the Merrimack show that the river is continuing to clean up even now, 35 years after the Clean Water Act changed it from an open sewer," said May. He also indicated that the low numbers were helped by the pleasant weather and diminishing flow on the river. The flow on the Merrimack has been dropping since the rains a couple weeks before. Flow was still over 5000 cubic feet per second, which is well above the historic average of around 2000 for this date, but this is well below the 50,000 cfs of a month ago. May noted that the Merrimack may look very low to drivers crossing the bridges in Nashua or Tyngsborough because of damage that the recent floods did to the dam in Lowell. Repairs to the dam are now underway and the river will be ponding up to its normal level shortly, according to the dam operators.

SWA and LAC volunteers test both rivers biweekly from June through September. Besides E. coli, tests are for dissolved oxygen, pH, phosphorus, temperature, and turbidity. The E. coli tests are performed at the Milford, Merrimack, and Nashua Wastewater Treatment Facilities. Dissolved oxygen tests are done at the Nashua National Fish Hatchery lab. The next tests will be done on Tuesday, July 25. Monthly tests on the Nashua River will also be available then. Past E. coli results are available on the SWA website at www.souhegan.org. Reports of the full testing program for past years are available at watershed libraries.


June 27th Description
LOWER HALF OF SOUHEGAN HAS HIGH E. COLI COUNTS

Although southern NH was spared the heavy rains and flooding down south and in upstate New York, high flows in the Souhegan and Merrimack Rivers was the dominant feature noted by volunteers collecting water quality samples on Tuesday morning, June 27th. Although flows were one-third the level of two weeks ago, the rivers were still very high and the current very fast. The Souhegan was running at 508 cubic feet per second, five times the normal historic flow of 96 for this date; flow on the Merrimack was 11,500 CFS, almost five times its 2540 expected flow. Drizzly weather for the three days prior to the water testing brought the flow on both rivers back up from slightly lower levels a week earlier. This drizzly weather also may have contributed to higher E. coli levels on both rivers from the first tests done two weeks ago.

The Merrimack River tested clean enough for swimming at all but two of the sites tested. The site at Goffs Falls near the railroad bridge and the site just upstream of where the Souhegan River comes into the Merrimack were 106 and 144 respectively, slightly higher than the 88 counts of E. coli bacteria colonies per 100 milliliters of water that is considered safe for public swimming areas in NH. All of the other sites between Manchester and Tyngesborough were below the 88 limit.

The Souhegan River, on the other hand, did not do as well. The fifteen miles of river upstream of the center of Milford tested clean. The fifteen miles downstream of the center of Milford did not fare so well. The site just upstream of the Oval, behind the Boys and Girls Club, tested at 188 colonies of bacteria and then the count jumped more than 100 to 292 just downstream of the Oval at the Swing Bridge. All of the readings downstream through Amherst and Merrimack also tested well over the 88 limit. The highest reading taken on the entire length of the river was 580 at the Amherst Canoeport on Rte 122 at the Amherst Country Club.

The site at the Boston Post Road Canoeport was not tested due to lack of volunteers, but it can be inferred that the water quality at that site was not healthy for swimming either. This is one of the popular summer swimming holes on the Souhegan. Anyone that would like to monitor one of the sites not presently covered may contact George May at 883-3409 or georgemay@adelphia.net. All of the sites showing NA, 'not available,' need volunteers. As one of the other volunteers put it, "It's not hard.. .and it gives a good feeling to be helping out." There are three sites on the Souhegan that need volunteers: one in Greenville, one in Merrimack, and one on Purgatory Brook in Mont Vernon, a major tributary of the Souhegan. There are also three sites that need volunteers on the Merrimack: one in Merrimack, one in Nashua, and one in Tyngesborough.

One of the surprises was the lower than expected count taken at the Downtown Wilton site. This is the second clean test taken at a site that has in the past always had very unhealthy water. This is also an area that is being looked at closely by the Souhegan Watershed Association to identify the DNA of bacteria that may be contaminating the river.

Drizzly weather and higher flows on these southern NH rivers didn't deter people and animals from getting out and enjoying the rivers however. Monitors sighted fishermen, swimmers, dogs, birds, and turtles enjoying the brief respite between rainstorms early Tuesday morning. The Nashua Rowing Club has their dock back in the water just downstream of the Taylors Falls Bridge in Nashua and participants were out rowing early Tuesday morning. Unfortunately, one of the monitors also noted evidence of a horse who left behind a pile of manure that will be washed into the Nashua River and contribute to the E. coli counts after several rainstorms.

The rivers have also warmed up to pleasant temperatures for human activity. The Souhegan averaged 68 degrees; and the Merrimack was 70 degrees.

The Nashua River Watershed Association is monitoring the Nashua River once a month this year. The last test was on June 17. The NH sites monitored had generally higher E. coli counts than the May 27 tests. This was expected. The very high count noted in May at the canoe launch at Mines Falls Park was back to a more reasonable 99 in June. All of the sites between Pepperell and the mouth of the river in Nashua were in the 125-130 range, marginally higher than acceptable for public swimming areas. Sites on the Nissitisit River, which flows from Lake Potanipo in Brookline into the Nashua River, tested very clean. Walker Brook in Mason, which flows into the Squannacook and then to the Nashua River, jumped from very low in the past to a higher, but still acceptable, 106. Generally all the Nashua River sites looked reasonably good this month.

The E. Coli samples are tested at the Milford, Merrimack, Nashua, and Pepperell Wastewater Treatment Facilities.

The next tests on the Merrimack and Souhegan will be done on July 11th. The results will be released as soon as the tests are completed. Testing takes 24 hours to grow the bacteria colonies.


June 13th Description
E. COLI TESTS ON NASHUA RIVER ADDED TO SOUHEGAN AND MERRIMACK FOR 2006 SEASON

The Souhegan Watershed Association (SWA) and the Merrimack River Local Advisory Committee (LAC) have begun biweekly water quality testing again this summer. This is the tenth year that SWA and LAC have been collecting data on water quality on these rivers. Twenty-one sites on the Souhegan are being monitored. Twelve sites along the Merrimack between Manchester and Tyngsboro are being monitored. And this year eight sites affecting the NH section of the Nashua River are included in the E. Coli bacteria reports.

Every other Tuesday morning SWA volunteers collect river water samples which are tested for temperature, E. Coli bacteria, phosphorus, dissolved oxygen, and turbidity. They also note any activities and concerns at their site. The E. Coli samples are tested at the Milford, Merrimack, and the Nashua Wastewater Treatment Facilities. The Nashua River samples are collected by Nashua River Watershed Council volunteers once a month and are tested at the Pepperell Wastewater Treatment Plant.

The E. Coli bacteria levels for all three rivers came in quite low for this first test of the year. Normally tests at this time of the year have been acceptably low; this year they seem even lower than expected. This may be attributed to the very high flows that have occurred in the last several weeks. Whatever bacteria could have been washed into the rivers from storm drains or riverbanks were washed in and washed away several rainstorms ago. And the high water was the most important attribute noted by all the volunteers. At least one of the sites could not be sampled because of the dangerous, high water. Another of the volunteers stepped off the bank at her site expecting two feet of water and went in up to her neck. She noted that the Souhegan was a chilly 57 degrees.

The flows on Tuesday morning were significantly higher than average for this time of year. The Merrimack was flowing at 30,500 cubic feet per second. Its historical average is 3500. The Souhegan was flowing at 1740 CFS; its historic average is 130. Several of the schools that are part of the SWA-sponsored Adopt-a-Salmon Family had to postpone releasing their classroom-raised salmon into the surging Souhegan River in the last several weeks.

The Souhegan River had two sites that came in above the 88 limit that is considered safe for public swimming areas. The Amherst Conservation land downstream of Beaver Brook was highest at 150. Indian Ledges in Merrimack was just barely over the limit at 90 colonies of bacteria per 100 milliliters of water. The Boston Post Road site in Amherst was not tested for lack of a volunteer and this site, a popular swimming hole in the summer, has historically tested well above 88.

Two sites on the Merrimack River also had bacteria counts over 88. Goffs Falls in Litchfield, near the railroad bridge that crosses the river, was 100. The site just upstream of the mouth of the Souhegan was just over the limit at 90. Though again the lack of volunteers for sites on the Merrimack may not be giving a completely accurate picture of the health of the river.

If anyone would like to help collect samples at any of the sites showing "Not Available," he can call the coordinator of the program, Ken Butenhof, at 644-3431 or George May at 883-3409.

Only one site on the Nashua River was high when tested on May 27. The test site at Mine Falls Park showed an exceptionally high 549. The other seven sites were well below 88. The next Nashua test will be on June 17th.

The next tests on the Merrimack and Souhegan will be done the morning of June 27th. The results will be released as soon as the tests are completed. Testing takes 24 hours to grow the bacteria colonies.


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