Souhegan Watershed Association

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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 2003

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) msn (dot) com" 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.


September 16th results
BACTERIA LEVELS INCREASE AT LAST TEST FOR YEAR

No sharks were found in the Merrimack River this week, but river monitors did find an increase in E. Coli bacteria on both the Merrimack and Souhegan Rivers. Spokesmen for the Souhegan Watershed Association and the Lower Merrimack River Local Advisory Committee, sponsors of the volunteer water quality monitoring program, attributed the high bacteria counts to the substantial rainfall just prior to the tests and to the presence of a large amount of debris that was washed into the rivers that had not had a chance to settle out.

Normally the Merrimack River tests very clean. This year four of the eight tests on the twelve sites between Manchester and Tyngsborough had no readings that would have been in violation of Class B waters standards for swimming and fishing. This week, however, saw almost all of the sites violating the standards. The program uses the stricter standards for public swimming areas as their target. A bacteria count higher than 88 would cause a public swimming area to shut down until the level decreased. Only the one site on the Merrimack, upstream of the mouth of the Souhegan River, met that standard.

Things were even worse on the Souhegan River. Some of the highest levels seen this season were found all along the Souhegan. Spokesmen attributed these higher counts to the smaller size of the river. The Merrimack can absorb more pollution because of its size. Pollution in the Souhegan shows up more because there is less water and flow to absorb it. The Merrimack was flowing higher than its historical level on Tuesday morning when the tests were taken; the Souhegan was flowing less than its historical level. Flow on the Souhegan was 35 cubic feet per second; its historical flow is 43 cfs. Flow on the Merrimack was 2300 cfs; its historical average is 1500.

Three Souhegan sites near the center of Milford had readings exceeding 3000. At the American Stage Festival site, just upstream of the Milford Oval, the reading was 3040. At the Swing Bridge, just downstream of the Oval, the sample had colonies too numerous to count (TNC). And at the next site downstream, behind Riverside Cemetery, the reading was 3020. The readings stayed in the 2000 range downstream through Amherst and never got to an acceptable level all the way to its confluence with the Merrimack.

George May, SWA president, noted that although the bacteria levels this week were very high, both rivers are normally relatively clean. Rainstorms wash bacteria and debris into rivers and cause the counts to go up.

This was the last test for this season. The program has been collecting chemical data on the rivers for eight years and publishes a comprehensive report sent to all of the watershed conservation commissions and to all the watershed libraries. Some of the data is available on the SWA website at http://www.souhegan.org">www.souhegan.org. It's expected that the program will continue again next year beginning in June. Volunteer monitors are always needed and can sign up by calling the coordinators, Ken Butenhof at (603) 644-3431 or George May at (603) 883-3409.

The program is also collecting benthic macroinvertibrates - bugs that live on the bottom of the river - for the next two Saturdays to get a biological reading on the health of the rivers. The volunteers will collect and identify the specific bugs found and match them up with a sliding scale of bugs that can tolerate pollution.

Volunteers at the Greenville, Milford, Merrimack and Nashua Wastewater Treatment Labs do the E. Coli tests. Testing for dissolved oxygen, necessary for fish and plant life, is done by volunteers at the Nashua National Fish Hatchery. Phosphorus testing is done by the Department of Environmental Services in Concord.

September 2nd results
SHARK DOESN'T RAISE E. COLI COUNTS ON MERRIMACK RIVERL

Besides doing water testing, volunteer water quality monitors report back on the activities they note at their sites. Reports of foam or oil on the water, fish activity, wildlife, boaters, fishermen are all reported on a regular basis. But monitors Chip and Jane Hemminsen had something special to report on Tuesday morning - a seven-foot long dead shark was floating in shallow water at the Thorntons Ferry boatramp in Merrimack. The shark had apparently been dumped there by someone who had removed all the teeth and cut off the fins and tail. The shark was reported to NH Department of Environmental Services, NH Fish &Game, Merrimack Police, and Merrimack Department of Public Works. The DPW pulled the shark out of the water and hauled it off to the landfill.

Other monitors reported seeing a Great Blue heron, beaver activity, and deer at the various 31 sites on the Merrimack and Souhegan Rivers monitored every two weeks during the summer by the Souhegan Watershed Association and the Merrimack River Local Advisory Committee. It was also reported that the containment booms are still in the Souhegan River to capture the oil spilled from Warwick Mills in New Ipswich several weeks ago.

The monitors perform tests for air and water temperature, dissolved oxygen, bacteria, turbidity, and phosphorus every two weeks. This month monitors will also do benthic macroinvertibrate tests. This involves collecting and identifying bugs that live in the river and deciding whether these bugs can tolerate pollution or require clean water to survive.

Although the dead shark was floating in the water at the time of the test, it did not raise the bacteria level. The test indicated a bacteria level of 32. This is well below the target level of 88 that the program is looking for. None of the other Merrimack sites had levels over the 88 level either. This is the fourth time out of seven tests this year that the Merrimack tested perfect at all the sites tested. This is in direct contrast to the cleanliness of the river when the Clean Water Act was enacted 30 years ago. At that time the Merrimack was listed as one of the ten dirtiest rivers in the United States. Now no raw sewage goes into the river except during periods of heavy rains.

The Souhegan River, however, did not test as well. All of the Merrimack River sites were below 88; almost all of the Souhegan sites were above 88. Only the headwaters in New Ipswich and the mouth of the river in Merrimack tested OK. Of the usual swimming holes on the Souhegan, only the site at the Turkey Hill Bridge in Merrimack tested below 88. The reading here was 31. School and cool weather would have played a part in keeping the kids out of the water at this time however.

The next monitoring test will be done on September 16. This will be the final test for this year. Past results are available on the SWA website at www.souhegan.org and in yearly reports in all watershed libraries. Monitoring at all the sites is done by SWA volunteers. The Greenville, Milford, Merrimack and Nashua Wastewater Treatment Labs do the E. Coli tests. Testing for dissolved oxygen, necessary for fish and plant life, is done at the Nashua National Fish Hatchery. Phosphorus testing is done by the Department of Environmental Services in Concord. Ken Butenhof, a PhD in chemistry, coordinates the program.

August 19th results
RIVER BACTERIA BACK TO NORMAL

As the rainfall returned to a more normal pattern, so did the E. Coli bacteria levels on both the Merrimack and Souhegan Rivers. The testing program sponsored by the Souhegan Watershed Association and the Merrimack River Local Advisory Committee found normal summer bacteria levels when they tested last Tuesday, August 19.

The tests two weeks ago had very high bacteria levels caused by the heavy rains shortly before the test date. The heavy rain caused a release of raw sewage directly into the Merrimack through the Combined Sewer Overflows (CSOs) in Manchester and Nashua. Nothing like that happened this week. There were several thundershowers within three days of the tests, but they were not heavy enough to do more than slightly increase bacteria levels in both rivers. River levels did increase, however. The Merrimack was flowing at 5600 cubic feet per second, well above its historic average of 1500 CFS. The Souhegan was twice its historic average at 93 CFS.

The Souhegan River had slightly higher than usual bacteria counts in the upper stretches of the river in New Ipswich and Greenville. Although the numbers are not high enough to be of concern, they are generally twice as high as normal. The highest number was 120 just upstream of Greenville Mill Pond. The target number SWA looks for is 88. Anything higher than that number would close public swimming beaches.

The only other site that had an unusual reading was at the Swing Bridge in Milford where the count was 460. The average for this site last year was 250. The urban setting and large number of ducks and other wildlife is thought to be responsible for the high readings normally found at this site.

The popular swimming hole at the Horseshoe in Wilton was 35, well below the 88 target. The other popular swimming hole at the Amherst Canoeport on Boston Post Road was not monitored this week, but tests here are almost always well above the safe target of 88. The average for the first four tests at this site this year is 280, and for all eight test last year it was 191. SWA has been looking for causes of the high E. Coli counts here, but so far hasn't been able to identify anything specific. Tests at Indian Ledges and at the Turkey Hill Bridge in Merrimack, where some swimming takes place, showed very low numbers, as usual.

The Merrimack River cleaned up nicely in the past two weeks. There was only one site, near the Sanders parking lot in Hudson, that had a reading higher than 88, and even the 139 reading here was lower than its historic average of 168. The Merrimack River almost always tests very clean for bacteria. This is a big change from when the Clean Water Act was enacted 30 years ago. At that time the Merrimack was listed as one of the ten dirtiest rivers in the United States. Today it is only when the CSOs in Manchester and Nashua release that counts go way up. And that is being remedied. Just recently Nashua mayor Bernie Streeter signed an agreement with EPA to build storage facilities to store large amounts of rainwater and sewage until the wastewater treatment plant is able to treat all of it. This is expected to clean the Merrimack even more and to save the city millions of dollars and the inconvenience of digging up most of the city's streets to replace the pipes, according to the study done by the Army Corps of Engineers.

The next monitoring test will be done on September 2. Past results are available on the SWA website at www.souhegan.org and in yearly reports in all watershed libraries. Monitoring at all the sites is done by SWA volunteers. The Greenville, Milford, Merrimack and Nashua Wastewater Treatment Labs do the E. Coli tests. Testing for dissolved oxygen, necessary for fish and plant life, is done at the Nashua National Fish Hatchery. Phosphorus testing is done by the Department of Environmental Services in Concord. Ken Butenhof, a PhD in chemistry, coordinates the program.

August 5th results
BACTERIA LEVELS LEAP AFTER HEAVY RAINS

Almost all of the sites tested along the Merrimack and Souhegan Rivers had exceptionally high E. Coli bacteria levels when tested on Tuesday, August 5. Heavy rains and thunderstorms on Monday washed bacteria into the rivers and caused the release of sewage meant for the wastewater treatment plants in Nashua and Manchester directly into the Merrimack. The testing by the Souhegan Watershed Association and Merrimack River Local Advisory Committee picked all of this up when they tested early Tuesday morning. This was their first test this year after heavy rains.

Many parts of Manchester and Nashua have a single pipe system that collects both the rainwater and sewage. Under very heavy rains the volume of water overwhelms the capacity of the waste treatment plants and the overflow is released directly into the Merrimack River. There are 26 of these combined sewer overflows (CSOs) in Manchester and all were releasing to the Merrimack on Monday. Several kayakers who attempted to take advantage of the higher flows on the Merrimack at the slalom course at Arms Park were put off by the sewage that was plainly visible in the water. Nashua has nine CSOs, five on the Nashua River and four on the Merrimack, and they were all releasing on Monday. Under normal conditions all of the combined rainwater and sewage goes to the waste treatment plant and is treated.

Nashua has just announced that the EPA will not require the city to dig up the streets and put in a two-pipe system. Instead the city will build storage tanks that will accept the excess combined water-sewage mix and hold it until the waste treatment plant is able to treat it. This is expected to save the city millions of dollars and still keep the river cleaner than it is now.

A number of the bacteria samples were lost due to an equipment malfunction at one of the labs doing the testing. But it is clear from the samples that were read that none of the sites on the Merrimack River were even close to an acceptable level for swimming. All of the Manchester samples were lost, but there was visible sewage in the river. The river cleaned up some as it moved toward Nashua, but the Nashua CSOs brought the level right back up again. The bacteria level measured at the Taylors Falls Bridge was 2000, a new record for this testing program.

The Souhegan River didn't fare much better. There are no CSOs on the Souhegan, but the bacteria washed in from streets, parking lots, farmers' fields, and the river banks enough to make it unacceptable at almost all the sites tested. The tests for Merrimack were lost, but even these usually acceptable sites were probably well over the limit of 88 colonies per 100 milliliters of water that is required for public swimming areas. The Horseshoe in Wilton almost always has acceptable levels, but this week it tested at 330. The Amherst Canoeport at Boston Post Road, another popular swimming spot, was 800.

One bright spot on the Souhegan was the stretch behind the American Stage Festival and Keyes Field in Milford. Two weeks ago saw an unusual spike to 1500 at this site. The Milford health officer walked the area looking for possible contamination but found nothing. Additional tests taken two days later had very low readings. This week that site tested at 610, which although high was in line with other readings along the river.

Monitors reported some oil in the water and along the riverbanks downstream of Highbridge in New Ipswich. Several weeks ago 200 gallons of oil spilled into the river when a boiler at Warwick Mills broke down. Five sets of booms between Highbridge and Greenville have been placed in the river to capture the oil.

These bacteria levels are generally valid for a period of three days, while the bacteria are alive. They give a pretty good picture of the general health of the river under normal and stressful conditions. Heavy rains usually cause an increase in the bacteria. Three days after the last of the heavy rains should see the bacteria levels coming back down to normal levels.

July 22nd results
BACTERIA LEVELS OK EXCEPT FOR SPIKE IN MILFORD

The Souhegan Watershed Association and Merrimack River Local Advisory Committee water quality testing program showed generally acceptable levels of E. Coli bacteria in both rivers except for a very high, dangerous reading taken in the Souhegan behind the American Stage Festival, across from Keyes Field.

The program looks for a target of less than 88 colonies of bacteria per 100 milliliters of water. This is the state standard for public swimming beaches. Every one of the sites tested on the Merrimack River, between Manchester and Tyngsboro, came in lower than 88. One in Manchester had no colonies that the test was able to measure. The Merrimack has tested very well for the last couple of years, reflecting the amazing cleanup that this river has experienced since the passage of the Clean Water Act thirty years ago. At that time the Merrimack was listed as one of the ten dirtiest rivers in the entire country. Now it tests very well for bacteria. In three of the four tests performed this year the Merrimack had no sites above the targeted 88.

The only problem with the Merrimack the program noted was its very low flow. At the time of Tuesday's test the flow was only 732 cubic feet per second. Historically it should have been flowing at 1815 CFS. The lack of precipitation up north has kept the river well below its historical flows all year.

The Souhegan River was within its normal flow range for this time of year. At the time of the test it was flowing at 35 CFS and its historical average on this date is 43. But the test site behind the American Stage Festival in Milford had a very high E. Coli reading of 1500. This number was estimated because it is well beyond the ability of the particular test to count correctly. This is the highest number ever seen by the testing program. The information was reported to the Milford health officer to investigate.

The numbers went back down to more normal levels at the next downstream site at the Swing Bridge in Milford. The level here was 280, well above the target 88 but more in keeping with its history as a downtown site. The average for all eight tests performed last year was 251 at the Swing Bridge. The river stayed above the 88 level through Amherst and peaked at the Amherst Canoeport at the Boston Post Road bridge. Here it measured 393, the highest level seen so far this year. This site almost always tests above a safe level and is a popular swimming hole. Swimmers here should expect bacteria-caused ear and eye infections, diarrhea or other gastrointestinal problems according to the program. The town of Amherst has posted no swimming signs here because of the pollution.

The other sites where kids swim all tested OK. The Horseshoe in Wilton, Indian Ledges and Turkey Hill in Merrimack all had levels well below the targeted 88. The site at Turkey Hill bridge had no bacteria at all. It has been reported, however, that no trespassing signs have been posted at the Horseshoe to curb teenage beer drinking and littering. The test results are only good for about three days, while the bacteria are alive, but they give a good picture of the general health of the river.

The next test will be done on August 5. Past results are available on the SWA website at www.souhegan.org and in yearly reports in all watershed libraries. The Greenville, Milford, Merrimack and Nashua Wastewater Treatment Facilities do the E. Coli tests. Testing for dissolved oxygen, necessary for fish and plant life, is done at the Nashua National Fish Hatchery. Phosphorus testing is done by the Department of Environmental Services in Concord. Ken Butenhof, a PhD in chemistry, coordinates the program.

July 8th results
BACTERIA LEVELS IN LOCAL RIVERS SURPRISE

The recent hot spell and lower flows in the Souhegan and Merrimack Rivers produced a couple of unexpected results when the rivers were tested for bacteria levels on Tuesday, July 8. The levels on the Souhegan generally increased from the tests two weeks ago, but the levels on the Merrimack decreased from two weeks ago. This happened despite the fact that the flow on the Souhegan was relatively normal for this time of year and the flow on the Merrimack was only half of its historic flow for this date.

Usually lower flows and higher temperatures produce an increase in the E. coli bacteria counts. The Souhegan counts generally increased in spite of the fact that the flow at the time of the test was 59 cubic feet per second and the historical average for this date is 55 CFS. Most of the river from New Ipswich to downtown Wilton was relatively clean. The Horseshoe, a popular swimming hole upstream of downtown Wilton, came in at 24 colonies per 100 milliliters of water. This is well below the 88 that the Souhegan Watershed Association recommends as the standard for safe swimming and the standard the state requires for public swimming beaches. Levels higher than that may cause ear and eye infections, diarrhea or other gastrointestinal problems in a small percentage of people. As the bacteria count goes up the percentage of people affected goes up.

Once into Downtown Wilton the levels increased above the targeted level and peaked in Milford behind Riverside Cemetery. The test here had a count of 720 bacteria colonies per 100 milliliters. All three of the tests at this site this year have been above the safe levels. The two prior tests this year were 153 and 233. The average of all eight of the tests last year was 218. Typically the bacteria levels stay higher than acceptable through Amherst until the river hits the town of Merrimack. And this is what the testing found again this time. The level at Indian Ledges in Merrimack dropped to 9, the lowest on the entire river. Both the Horseshoe, which had good levels on the upper river, and Indian Ledges on the lower river are stretches of rapids, which may account for the lower readings.

The Amherst Canoeport on Boston Post Road near Souhegan High School did not fare so well. This popular swimming hole had a count of 230. That was actually down from the prior test two weeks before when the count was 385. The bacteria numbers give a general picture of the health of the river rather than an exact reading. However, this site almost always has higher than acceptable levels of bacteria. The average of all last year's tests was 191. The river in this section meanders slowly back and forth, which may contribute to the higher counts here. The SWA is actively looking for correctable causes of the higher counts here however.

The Merrimack River produced a pleasant surprise with very low numbers. The flow in the Merrimack at the time of the testing was 1000 CFS, but its historical average going back over 60 years is about 1800 CFS. The river had only slightly more than half of the flow it should have had. But the bacteria levels actually improved over the tests two weeks ago. Two weeks ago four of the twelve sites had counts higher than 88. This week none of the sites were above that level. The 600 level that was observed at the Sagamore Bridge two weeks ago decreased to 36 this week. The Merrimack River has been a real success story as far as cleaning up goes. It is only when heavy rainstorms overwhelm the capacities of the sewage treatment plants in Manchester and Nashua that the bacteria counts go up to non-safe levels. When the sewage treatment plants cannot accommodate the flow from the streets' stormdrains, raw sewage is discharged directly into the Nashua and Merrimack Rivers from 35 different pipes in 35 different sites. These two communities in New Hampshire and three others in Massachusetts that have single pipe systems for sewage and stormwater are in the process of studying how to best correct this problem under the aegis of the EPA.

The only concern reported by observers during the test on the Merrimack was bubbles over a large stretch of the river. This has also been observed a number of times before and the Merrimack River Local Advisory Committee believes it can be traced to airplanes being washed at the Manchester Airport and has asked DES to investigate.

Observers along the Souhegan noted that the Mountain Laurel was in bloom and beautiful.

Volunteers with the Souhegan Watershed Association and the Merrimack River Local Advisory Committee have performed these biweekly tests for the last seven years. These results are all tabulated on the SWA website at www.souhegan.org and in yearly reports in all watershed libraries. The Greenville, Milford, Merrimack and Nashua Wastewater Treatment Facilities do the E. coli tests. Testing for dissolved oxygen, necessary for fish and plant life, is done at the Nashua National Fish Hatchery. Phosphorus testing is done by the Department of Environmental Services in Concord. Ken Butenhof, a PhD in chemistry, coordinates the program.

June 24th results
BACTERIA LEVELS RISE MODESTLY ON LOCAL RIVERS

Bacteria levels on the Merrimack and Souhegan Rivers increased over the last two weeks according to the testing done on Tuesday, June 24, by the Souhegan Watershed Association and Merrimack River Local Advisory Committee. An increase in temperatures and sudden rainfall is probably the reason for the increase according to George May, president of the Souhegan Watershed Association. "In spite of the frequent showers in the last couple of weeks that should have already washed all the possible pollution into the rivers, we had a pretty good downpour the night before the test and that probably accounts for the increase in E. coli bacteria," said May. Generally bacteria levels go up after a rainstorm.

Both ends of the Souhegan River tested very well and the middle stretch through Milford and Amherst not-so-well. This has been the trend for the past seven years that the testing has gone on according to May. The bacteria level went as high as 330 colonies of E. coli per 100 mililiters of water behind Lorden Plaza after passing through the center of Milford. It cleaned up to only 12 and 18 colonies when tested in Merrimack. The program uses 88 colonies as the cutoff for safe swimming. This is the standard used by health officials for public swimming areas. Any levels higher than that may cause ear and eye infections, diarrhea or other gastrointestinal problems in a small percentage of people. As the bacteria count goes up the percentage of people affected goes up.

The usual areas of human contact on the Souhegan: the Horseshoe in Wilton, Indian Ledges and the Turkey Hill Bridge in Merrimack, tested fine. The Amherst Canoeport at Boston Post Road was well above the safe level at 385. This again has been the pattern over the last seven years of testing according to May.

The Merrimack River was tested from Manchester to Tyngsborough and generally had positive results. The bacteria counts increased above the 88 cutoff at the Thorntons Ferry boatramp in Merrimack but not dramatically except for a spike to 600 colonies near the Sagamore Bridge in Hudson. The numbers being reported are good for only a few days, while the bacteria are alive, but they do indicate the general health of the river or problems at that moment. They also show a historic trend toward healthy or unhealthy sections of the river. Usually the Merrimack has very good numbers according to May.

Flow on the Souhegan at the time of the test was 326 cubic feet per second. Historic flow for that date is 100. Flow on the Merrimack was 1810 and historic flow for that date is 2500 CFS.

Testing is done every two weeks by trained volunteers. Bacteria samples are tested at the Greenville, Milford, Merrimack and Nashua Wastewater Treatment Facilities. Testing for dissolved oxygen, necessary for fish and plant life, is done at the Nashua National Fish Hatchery. Phosphorus testing is done by the Department of Environmental Services in Concord. Ken Butenhof, a PhD in chemistry, coordinates the program.

June 10th results
TESTING OF SOUHEGAN AND MERRIMACK RIVERS BEGINS 2003 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 seventh summer that SWA and LMRLAC have been collecting data on water quality on these rivers. Nineteen sites on the entire length of the Souhegan are being monitored. Twelve sites on the Merrimack between Manchester and Tyngsboro are being monitored.

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 indicate the general health of the river water or 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 will also be 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 at local libraries and conservation commissions within the two watersheds.

Lots of continuing rain showers for the last couple of weeks seems to have washed away any bacteria along both rivers. All of the monitors noted very high water levels and high flows when the testing was done on Tuesday, June 10. The Souhegan flow was measured at 334 cubic feet per second (CFS) at the time testing was done; almost three times the historic flow of 130 CFS for this date going back over 30 years. The Merrimack was flowing at 5300 CFS; the average flow to be expected is 3400 CFS. "The concern for drought that was so evident last year seems to have disappeared this year. Ample rain and snow has brought up both the rivers and aquifers around the area," said SWA president George May.

The highest bacteria levels were seen on the Souhegan as usual. The highest reading on the Merrimack was only 68 taken at the Taylors Falls Bridge between Nashua and Hudson. This is well below the 88 level that the state uses for public swimming areas and the standard that the SWA is looking for. The Merrimack typically tests at very acceptable levels all summer long. "There may be other problems with the water quality that we do not test for, but bacteria is not one of them. It's very safe in that respect," said May.

Half of the sites on the Souhegan had bacteria levels higher than 88, most of them in the stretch between the center of Milford and the Merrimack town line. This has been typical again of what has been seen in the past. None of sites had alarmingly high results though. The highest, 159, was seen at the Swing Bridge, right after the river has gone through the center of Milford and picked up the inflow from Great Brook, which drains the area along Rte 13.

The Boston Post Road Amherst Canoeport near Souhegan High School is a popular swimming spot when the weather warms up. It had a reading of 110, not yet alarmingly high. Swimming in water with counts higher than 88 may cause ear and eye infections, diarrhea or other gastrointestinal problems in a small percentage of people. As the bacteria count goes up the percentage of people affected goes up.

The Horseshoe in Wilton another popular swimming area had an acceptable reading as expected. The reading here was 52.

All of the testing is done by trained volunteers; the bacteria samples are tested at the Milford Wastewater Treatment Facility, the Merrimack Wastewater Treatment Facility, and the Nashua Wastewater Treatment Facility. Testing for dissolved oxygen, necessary for fish and plant life, is done by the Nashua National Fish Hatchery. Phosphorus testing is done by the labs at the NH Department of Environmental Services in Concord. Ken Butenhof, a PhD in chemistry, coordinates the program.

"We're starting off with good, clean rivers this season. Let's hope it stays this way as the weather warms up," said May. "Typically we see stresses on both rivers as the summer progresses, but we are seeing an improvement over several years of testing. Things are getting better," he said.


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