Souhegan Watershed Association

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

Water Testing Results
Summer 2004

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 2003, 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.


August 31st results
E. COLI HIGH AGAIN ON SOUHEGAN, MERRIMACK AND NASHUA RIVERS

This has been a tough time for the Souhegan and Merrimack Rivers. Rains just before the testing on Tuesday morning washed high levels of E. coli bacteria into the local rivers for the second time in the last two weeks. Six sites on the Souhegan tested at an acceptable level on Tuesday, but four of those were in the headwaters, where they didn't get any rain. Only one site monitored on the Merrimack tested at an acceptable level. All of the other 27 sites tested had bacteria levels higher than 88 colonies per 100 milliliters of water. This is the level at which public swimming areas would be closed for health reasons. Counts higher than this level will cause ear and eye infections and gastrointestinal problems in susceptable swimmers.

The average E. coli reading on the Merrimack was almost 300, more than three times the acceptable level. On the Souhegan the average was slightly higher than 300. The highest count for either river, 640, was measured at the bridge over the Souhegan at Pine Valley Mill near the Milford/ Wilton line. Close second was the 600 reading at the Rte 122 bridge across from the Amherst Country Club. Counts varied greatly during this test however. Tests were taken shortly after the rains washed runoff from the banks and stormdrains into the rivers and so the counts seem to offer the pollution levels for the exact testing area itself. There was little time for the bacteria to migrate and blend in. Sites at the Milford Drive-In and below Hartshorn Brook both had low levels of 65 and 30 respectively. But they were the exceptions. Except for the headwaters, the next lowest numbers were 120 measured behind Lorden Plaza, just downstream of the Milford Wastewater Treatment Plant, and 168 measured at the Amherst Conservation land, downstream of the Amherst Country Club.

On the Merrimack between the Amoskeag Dam in Manchester and the Tyngesborough Bridge numbers ranged from a low of 76 to 552. The flow on the Merrimack at the time of the tests was double its historic average. Twice as much water was in the river as is normal. The flow level on the Souhegan was also higher than average but not by a significant amount. The normal flow on the Souhegan for this date is 39 cubic feet per second and the flow measured at 8am Tuesday was 47 CFS, about 25% higher than average.

Now that school is back in session there is less interest in swimming. However, for the second test in a row none of the normal swimming holes had a positive test. The Horseshoe in Wilton was not tested this week; the Amherst Canoeport on Boston Post Road was 215; and the Turkey Hill Bridge area in Merrimack was 344.

Also included for the first time are E. coli readings for the Nashua River. These results are part of a monitoring program by the Nashua River Watershed Association that checks water quality at three NH sites on the Nashua River and two on the Nissitissit River, a tributary of the Nashua. The tests are done once a month during the summer. More information is available on their website www.NashuaRiverWatershed.org. These tests were conducted on August 21, after heavy rains. Although the tests were done on different days, the weather conditions were similar for all the tests and so the results can be reasonably compared. E. coli bacteria probably live for three days but provide a snapshot of the water quality in the various locations over a period of time. The earlier July results, done during clear, warm weather conditions, were all lower than 88 colonies per 100 milliliters except for the Bohannon Bridge site on the Nissitissit. That count was 172, double the target level. This site had the highest reading for August also, 530. We hope to make the Nashua River results available again after next month's tests.

Trained volunteers monitor the Souhegan and Merrimack Rivers every other Tuesday morning. The bacteria samples are read at the Greenville, Milford, Merrimack, and the Nashua Wastewater Treatment Facilities. The Nashua National Fish Hatchery provides the lab for a volunteer to read the dissolved oxygen, which is necessary for fish and plant life. NH Department of Environmental Services in Concord does the phosphorus testing.

Reports for the eight years that this program has been going on are available from the Souhegan Watershed Association, on their website at www.souhegan.org, and at all the watershed libraries.

NASHUA RIVER SITES FOR AUG 21st:

Mine Falls Park at the boat ramp next to stadium, Nashua 410
Rte. 111 Bridge, Hollis 200
Canal Street at BAE parking lot, Nashua 500

NISSITISSIT RIVER SITES:

Bohannon Bridge, Brookline 530
Just downstream of the Potanipo Lighthouse, Brookline 170

August 17th results
RAINS BRING E. COLI LEVELS WAY UP

Approximately one inch of rain fell in the two days prior to Tuesday's tests on the Souhegan and Merrimack Rivers conducted by the Souhegan Watershed Association and the Lower Merrimack River Local Advisory Committee. This brought the E. coli bacteria counts to unacceptable levels at most sites on both rivers. The target level of 88 was exceeded on all but two sites of the 26 tested on the Souhegan and all but four of the 10 sites tested on the Merrimack River.

The large size of the Merrimack River is better able to absorb the effects of moderate rains washing pollution into the rivers than the much smaller Souhegan River. And the Merrimack was probably lowered at the various dams along the river in anticipation of more severe rains that could have been caused by Hurricanes Bonnie and Charlie. This would have flushed out pollution levels that otherwise might have shown up. At very heavy rain events the combined street and parking lot storm drains and sewer pipes that normally go to the waste treatment plants, where it is treated before being discharged to the Merrimack River, overwhelm the capacity of the waste treatment plants in Manchester and Nashua and it is discharged directly to the river without any treatment at all. There are 26 Combined Sewage Overflows (CSOs) in Manchester and 9 in Nashua that could discharge raw sewage directly to the river during severe rains. This was not the case this time. And Nashua is working with the EPA to build two large storage tanks to accept the discharge from their nine CSOs so that all of the sewage and storm water can be stored until the rains let up enough so that the waste treatment plant can treat the stored effluent. The city administration is trying to prove that this is a cleaner, cheaper way to solve the EPA mandate to clean up the river than digging up all the streets and replacing the single pipe system with separate pipes for sewage and storm water. The highest reading found on the Merrimack this week was 160 at Goffs Falls in Litchfield, just downstream of the Manchester wastewater treatment plant. This was less than half of the average found on the Souhegan and only one-quarter of the highest reading recorded there.

The Souhegan's smaller size shows the effects of the rains much more than on the Merrimack. Except for two sites between New Ipswich and Greenville all of the sites had very high bacteria levels. The average E. coli count between Wilton and the mouth of the river in Merrimack was over 350, four times the acceptable 88 level. Any count above 88 would close a public swimming area. This week all three of the usual swimming holes on the Souhegan had unacceptable readings. The Horseshoe in Wilton was 240. The Boston Post Road Canoeport in Amherst was 245. The Turkey Hill Bridge area in Merrimack was 230. Swimmers at these levels are exposing themselves to ear and eye infections, diarrhea, and other intestinal problems. No place from Wilton downstream was safe for human contact. A peak of 738 was recorded behind Lorden Plaza, just downstream from the Milford Wastewater Treatment Plant.

A couple of surprises showed up on the Souhegan. The river had similar high counts as it wandered alongside Route 101A from West Milford to the Oval. But at a new site just added at Emerson Park to test the effects of Great Brook the river cleaned up considerably. This seems to indicate that Great Brook is cleaner than the Souhegan during periods of moderate rain. This site is just upstream of a small dam under the bridge at the Oval. Then at the Swing Bridge above the next dam just 300 yards further downstream the count zoomed up to 447 and then just as quickly dropped to 282 in another 100 yards when tested below the dam.

From here the river stayed in the 400-500 range as it meanders past the Amherst Country Club area until it reached the Boston Post Road Canoeport where it actually dropped to 245. This is the site that has had consistently high counts that occasioned the pilot DNA testing that is being done as a joint project by SWA, ENSR International and UMass Boston. It is hoped that testing the DNA of the river bacteria will identify the source of the pollution so it can be prevented.

The monitors at various sites on both rivers noted lots of flowers, birds, and water animals. One volunteer noted that PSNH workers were picking up and transporting eels over the Amoskeag Dam on Tuesday morning.

The Souhegan Watershed Association and the Lower Merrimack River Local Advisory Committee use trained volunteers to monitor the two rivers every other Tuesday morning at 40 different sites. The E. coli tests are done at the Greenville, Milford, Merrimack, and Nashua Wastewater Treatment Facilities. The Merrimack Wastewater Treatment Plant is preparing all the DNA samples, which are then sent to the Biology Department at UMass/Boston, where all the DNA work is being done. The Nashua National Fish Hatchery provides the lab for a volunteer to read the dissolved oxygen, which is necessary for fish and plant life. The lab at the NH Department of Environmental Services in Concord does the phosphorus testing. Ken Butenhof, PhD, is the coordinator for the monitoring program.

Reports for the eight years that this program has been going on are available from the Souhegan Watershed Association, on their website at www.souhegan.org, and at all the watershed libraries.

August 3rd results
DNA SAMPLES TAKEN FROM SOUHEGAN RIVER

Nine new sites along the Souhegan River were added to the water quality monitoring program this week in preparation for DNA testing of the bacteria in the river. This pilot program may help in determining the origins of the bacteria and possibly lead to ways to decrease pollution. The DNA testing will continue through the three additional biweekly monitoring dates scheduled for this year.

This week's samples are part of a research project underway within the watershed to take a closer look at the bacteria that has turned up within the Souhegan River. ENSR International and UMass/Boston have selected 20 river sites as a first step to map E. coli profiles as the river passes through urban, agricultural, and rural settings between Wilton and Merrimack. The profiles will be identified using a DNA fingerprinting technique developed at the Biology Department at UMass/Boston. The project is being funded by ENSR's Research and Development Program and supported by the Souhegan Watershed Association volunteers.

The E. coli levels along the Souhegan and Merrimack Rivers were fairly low when tested on Tuesday morning, about what was expected by the monitors. This is the eighth year that the SWA has been collecting chemical and biological data on the two rivers. Generally periods of dry weather produce low E. coli counts. After heavy rainstorms, when stormwater is washed into the rivers, the E. coli counts go up. There had been no significant rain on the three days prior to the Tuesday morning tests. The bacteria only live for about three days.

E. coli are an indicator species for pathogens that can cause health problems for people that come in close contact with the river water. Swimmers in particular can experience gastrointestinal problems and get ear and eye infections whenever the E. coli counts go over the 88 colonies per 100 milliliters of water that would close a public beach.

There are several spots along the Souhegan and Merrimack where kids swim. Three of the sites on the Souhegan that are regular swimming holes are monitored by these tests. The swimming hole at the Amherst Canoeport on Boston Post Road has been a source of high bacteria counts almost every test. The DNA testing was started to especially target this site and may help to clean it up in the future. This week's tests, however, found acceptable levels of E. coli at all of the Souhegan swimming holes. The Horseshoe in Wilton as usual had an acceptable level. This week it was 10. Turkey Hill Bridge in Merrimack had a count of 15. The count at the Boston Post Road site was 90, acceptably close to the 88 target level. However, at a new site this week just 500' upstream of the Boston Post Road Bridge the count was 113. And at another new site less than a mile upstream the count was 95. It appears that the count increases as the river approaches Boston Post Road.

The flow on the Souhegan was exactly at its historical level for this time of year. The flow and the lack of rain for the three days preceding the tests produced the best test for bacteria on the river this year. We have to go back to the first test at the beginning of June to see comparable results.

The upper reaches of the river in New Ipswich and Greenville all had low counts. It was not until the river reached Downtown Wilton that an unacceptable level of 208 was found. This was the highest level of all of the 40 tests on the two rivers done this week. The river then cleaned up until it reached the downtown area of Milford, and even then the counts were only slightly elevated. Slightly elevated counts were measured behind Lorden Plaza, again near Boston Post Road, and finally at a new site at Seaverns Bridge in Merrimack. Except for these slightly high counts, all the other sites were fairly clean.

The flow on the Merrimack River was almost twice as high as its historical level for this date. A slightly different picture was seen compared to the much smaller Souhegan. The only count higher than the 88 target level was 146 measured at the Taylors Falls Bridge in Nashua. And although four of the twelve sites were not monitored this week, the bacteria levels seemed to be about where they should be at this time of the year according to Ken Butenhof, coordinator for the program. The Merrimack is almost always clean as far as bacteria is concerned, and that's what appears this week. Except during heavy rains the Merrimack has very low E. coli levels.

Trained volunteers monitor the two rivers every other Tuesday morning. The bacteria samples are read at the Greenville, Milford, Merrimack, and the Nashua Wastewater Treatment Facilities. The Nashua National Fish Hatchery provides the lab for a volunteer to read the dissolved oxygen, which is necessary for fish and plant life. NH Department of Environmental Services in Concord does the phosphorus testing.

Reports for the eight years that this program has been going on are available from the Souhegan Watershed Association, on their website at www.souhegan.org, and at all the watershed libraries.

The next test is scheduled for August 17. The E. coli tests take 24 hours to complete and will be available the following day.

July 20th results
E. COLI LEVELS VARY WIDELY ON SOUHEGAN AND MERRIMACK RIVERS

Many volunteers had to brave lots of wet brush and myriads of mosquitoes to get their water quality samples from the Souhegan and Merrimack Rivers on Tuesday morning, July 20. There were heavy showers all day Monday, the day before the test, in various parts of both watersheds. Heavy rains wash pollution and bacteria into the rivers from storm drains and riverbank runoff. But some of the areas received very little rain from the spotty showers. As a result, E. coli levels varied quite a bit over the two watersheds. Over an inch of rain fell in a swath west to east from Milford to Hudson. But very little rain fell in the Souhegan headwaters and very little in Manchester and Nashua. E. coli levels on the Souhegan headwaters in New Ipswich, Greenville, and Wilton were somewhat elevated from earlier tests but about where they were expected to be at this time of year. The same was true for the Merrimack River in Manchester and Nashua. These were the areas that received little rain.

The rain along the Souhegan through Milford and Amherst brought very high E. coli levels, the highest seen so far this year. The highest count, 800, was experienced at the site behind Lorden Plaza in Milford. The river never got back to acceptable levels until it reached the Merrimack Village Dam at the Daniel Webster Highway, almost at the mouth of the river. The level at this site was 87, only one number better than the 88 target level that would close public swimming areas. The state would close a public beach if the E. coli level exceeded 88 colonies of bacteria per 100 milliliters of water. Numbers above this level cause ear and eye infections and gastrointestinal problems in a small number of swimmers. As the numbers increase, the percentage of swimmers getting sick increases.

Of the three usual swimming holes on the Souhegan only the Horseshoe in Wilton had acceptable numbers. The count there was 56. This spot almost always has good numbers. The Boston Post Road Canoeport in Amherst had a very high count, 480. This spot almost always has unacceptable numbers. The Turkey Hill Bridge site in Merrimack, which usually has acceptable numbers, had an unacceptable 170 count this week.

The Souhegan Watershed Association has begun a pilot program with UMass Boston and a private company to try to identify the sources of the bacteria that show up at the Boston Post Road Canoeport swimming hole. Previous attempts to locate where the bacteria is coming from using visual inspections and chemical tests haven't been fruitful. The UMass project will use DNA tracking.

Because Manchester had very little rain on Monday, the E. coli counts on Tuesday were very low. The counts increased as the Merrimack picked up the flows from the Piscataquog, Souhegan, and Nashua Rivers and exceeded the 88 target level beginning at the Thorntons Ferry boat ramp in Merrimack. It got back to an acceptable level of 86 at the Tyngsborough Bridge. Except during rainy periods the Merrimack has had very low E. coli levels.

The Souhegan Watershed Association and the Lower Merrimack River Local Advisory Committee use trained volunteers to monitor the two rivers every other Tuesday morning at 31 different sites. The bacteria samples are read at the Greenville, Milford, Merrimack, and the Nashua Wastewater Treatment Facilities. The Nashua National Fish Hatchery provides the lab for a volunteer to read the dissolved oxygen, which is necessary for fish and plant life. The labs at the NH Department of Environmental Services in Concord do the phosphorus testing.

July 6th results
LACK OF RAIN BRINGS E. COLI DOWN

Water quality tests performed on the Souhegan and Merrimack Rivers on Tuesday morning, July 6, showed very low bacteria levels on both ends of the Souhegan River and very low levels all along the Merrimack between Manchester and Tyngsborough.

The very low bacteria levels on the upstream reaches of the Souhegan increased beyond the target 88 level through Milford and Amherst and decreased to acceptable levels by the time it reached Merrimack. 88 colonies of bacteria per 100 milliliters of water is the cutoff level for public swimming beaches. Levels higher than 88 will cause gastrointestinal problems and ear and eye infections in a small percentage of swimmers and as the number of bacteria colonies increase, the percentage of health problems increases. Public beaches are closed beyond this target level. The site behind Lorden Plaza in Milford jumped to 400 this week, up from 150 for the last two biweekly tests. From here on downstream the levels kept decreasing, but still stayed above 88, until the river reached Merrimack.

The three swimming holes on the Souhegan tested about the same as usual. The Horseshoe in Wilton and Turkey Hill Bridge in Merrimack both had levels well below 88. Both of these sites test acceptably most times. The Boston Post Road Canoeport in Amherst had an unacceptable level of 220. This site has unacceptable levels most times. The SWA has spent many hours and many tests trying to determine why this popular swimming hole has high bacteria. They are planning on teaming up with a UNH study using DNA to find what kind of animals are producing the E. coli at this site.

Except for the 118 reading measured near the Sagamore Bridge in Nashua, all of the other sites on the Merrimack River were well below the 88 level. The Merrimack River usually tests very low for bacteria pollution. The river has cleaned up dramatically since the passage of the Clean Water Act 30 years ago when it was listed as one of the ten dirtiest rivers in the USA, pretty much an open sewer. There are still discharges of raw sewage to the Merrimack during periods of heavy rain when the stormwater overwhelms the sewage treatment plants in Nashua and Manchester. The City of Nashua, under orders from EPA, is building huge holding tanks to accept stormwater during heavy rains which can be processed by the Wastewater Treatment Plant after the rains stop. This innovative program will save the city millions of dollars and prevent having to dig up most of the city's streets to install stormwater catchbasins and pipes.

Both rivers were below their historical averages for this date. The Souhegan was flowing at 52 cubic feet per second. The Merrimack at 1590 CFS. Their historical averages are 64 and 1920 respectively.

Every other Tuesday morning SWA volunteers collect river water which is tested for temperature, E. coli bacteria, phosphorus, dissolved oxygen, and turbidity. They also note activities and concerns at their site.

The bacteria counts for each site all season long as well as past years' results are also available on the SWA website, www.souhegan.org. Printed copies of the reports from past years showing all of the tests performed are also available from the SWA and at local libraries and conservation commissions within the two watersheds.

Trained volunteers do all of the testing. The bacteria samples are tested at the Greenville, Milford, Merrimack, and the Nashua Wastewater Treatment Facilities. The Nashua National Fish Hatchery does testing for dissolved oxygen, necessary for fish and plant life. The labs at the NH Department of Environmental Services in Concord do the phosphorus testing. Ken Butenhof, a PhD in chemistry, coordinates the program.

June 22th results
MERRIMACK RIVER CLEAN OF BACTERIA

Not a single site on the Merrimack River between Manchester and Tyngsborough exceeded the limits for E. coli bacteria during the biweekly testing done by volunteers with the Merrimack River Local Advisory Committee. The tests were done on Tuesday morning, June 22. The Local Advisory Committee is a state appointed group of local citizens responsible for advising the state on concerns for rivers in the Rivers Management and Protection Program. The lower Merrimack is one of fourteen protected rivers in the state.

The results for the Souhegan River, another protected river, were not so good. But this was expected by the testers. The Souhegan is a much smaller river with a much smaller flow rate. Sections of the river through Amherst meander back and forth and the flow slows almost to nothing during the summer. The river is also much shallower so the water temperature warms up more quickly and this is a breeding ground for bacteria. Of the three swimming holes on the Souhegan, two exceeded the 88 target limit for dedicated swimming areas. The swimming hole at Turkey Hill Bridge in Merrimack registered only 14 E. coli colonies per 100 milliliters of water, but the Boston Post Road Canoeport in Amherst reading was 156, and the Horseshoe in Wilton was 94. These are still low readings, but any reading over 88 may cause intestinal problems, diarrhea, ear or eye infections in a small percentage of swimmers. The Boston Post Road Canoeport site is a popular swimming hole, but it almost always has unacceptably high E. coli counts. And generally the counts will go up as the water warms up during the summer.

Two sites on the Souhegan had fairly high readings. Downtown Wilton had a reading of 460 and the site at the Amherst Conservation land across from the Amherst Country Club had a reading of 405. Downtown Wilton is heavily populated and has many storm drains that can carry pet waste or other pollutants directly to the river. The Amherst Conservation land, however, is not populated at all. The test site is just downstream of Beaver Brook, which may carry pollutants from more populated areas into the river. Two weeks ago this site had a reading of 500.

The water level on both rivers was drastically lower than two weeks ago. Two weeks ago both rivers were above their historic averages for that date. At this test both rivers had dropped below their historic averages.

Volunteers, who two weeks ago noted and picked up a lot of trash, noted that no trash had accumulated this time. They also noted the presence of many mayfly nymphs along the Souhegan, a favorite food of the salmon and trout and indicator specie for very clean water. The volunteers collect samples of river water to be analyzed for dissolved oxygen, total phosphorus, and E. coli bacteria. They also note air and water temperatures, turbidity, activities and concerns. A beaver was spotted on the Merrimack and a Great Blue Heron on the Souhegan.

The bacteria samples are tested at the Greenville, Milford, Merrimack, and the Nashua Wastewater Treatment Facilities. The Nashua National Fish Hatchery does testing for dissolved oxygen, necessary for fish and plant life. The labs at the NH Department of Environmental Services in Concord do phosphorus testing. Ken Butenhof, a PhD in chemistry, coordinates the program.

The next test will be done the morning of July 6th.

June 8th results
TESTING ON SOUHEGAN AND MERRIMACK RIVERS BEGINS THE 2004 SEASON

The Souhegan Watershed Association (SWA) and the Merrimack River Local Advisory Committee (LMRLAC) have begun their biweekly water quality testing again this summer. This is the eighth summer that SWA and LMRLAC have been collecting data on water quality on these rivers. Nineteen sites along the entire length of the Souhegan are being monitored. Twelve sites along the Merrimack between Manchester and Tyngsboro are being monitored.

Every other Tuesday morning SWA volunteers collect river water which is tested for temperature, E. Coli bacteria, phosphorus, dissolved oxygen, and turbidity. They also note activities and concerns at their site. At this first test of the year they especially noted a large amount of trash and litter that had accumulated since last fall. And they cleaned it up. This first test was done on a beautiful sunny day. Volunteers also noted all kinds of activities along both rivers. Human activity included boating, swimming and fishing. Animals noted were deer, a nosy beaver, raccoons, and several kinds of birds - including two Great Blue Herons. And, of course, lots of mosquitoes.

Both rivers were above their normal flow for this date but were declining from much higher levels earlier this spring. The Souhegan was flowing at 168 cubic feet per second (CFS) and the Merrimack at 5669 CFS.

One of the tests being done is for E. Coli bacteria. Bacteria levels below 88 are considered safe for public swimming areas. The numbers being reported are good for only a few days, while the bacteria are alive, but they do give a snapshot of the river or indicate problems at that moment. They also show a historic trend toward healthy or unhealthy sections of the river. SWA and LMRLAC will release the bacteria counts as soon as they are available, generally two days after the actual testing. The bacteria counts for each site all season long as well as past years' results are also available on the SWA website, www.souhegan.org. Printed copies of the reports from past years showing all of the tests performed are also available from the SWA and at local libraries and conservation commissions within the two watersheds.

Generally both rivers looked good for E. Coli levels for this first test. There were a couple of sites that tested higher than expected and several that tested lower. The upper sections of the Souhegan showed no testable bacteria levels at all. The sections of the Souhegan going through downtown Wilton and Milford also tested much better than expected. Normally high bacteria counts would show up where the population and stress on the river increases. This week's levels would be considered good. Downtown Wilton was 125 and downtown Milford only 39. Most of the Merrimack also had very low levels of bacteria, but that was expected. The Merrimack has cleaned up dramatically since the passage of the Clean Water Act.

There were a few sites where the bacteria levels exceeded expectations. The site bordering the Fairway Road conservation land in Amherst read 500. This site is just downstream from Beaver Brook, which may have contributed to the high level. Also the reading at the Sagamore Bridge in Hudson was 460, almost as bad. The level at the boat ramp at Thorntons Ferry in Merrimack was 224, the only other site on the Merrimack with a level higher than the 88 target.

Trained volunteers do all of the testing; the bacteria samples are tested at the Greenville, Milford, Merrimack, and the Nashua Wastewater Treatment Facilities. The Nashua National Fish Hatchery does testing for dissolved oxygen, necessary for fish and plant life. The labs at the NH Department of Environmental Services in Concord do phosphorus testing. Ken Butenhof, a PhD in chemistry, coordinates the program.

There is still a need for volunteers for a couple of sites. Anyone interested can contact George May at 883-3409. The next test will be done the morning of June 22nd.


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