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,
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:
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 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
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 ½ 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
firstname.lastname@example.org. 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
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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