Souhegan Watershed Association

Souhegan River Water Testing Results
Summer 1999

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, disolved oxygen, temperature, and bacteria. Weather and streamflow information was also recorded when water samples are collected.

The 1998 results are available in a report that can be found in local libraries and they are summarized here. The current E-coli results this year are available here.

This monitoring program is conducted by trained volunteers who believe in cleaner rivers. Financial support for the program comes from a grant from NHDES and local conservation commissions. 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. If you would like to help continue this monitoring effort, please contact George May at 883-3409 or georgemay@msn.com.

September 14th results
RIVER BACTERIA COUNTS IN LOCAL RIVERS CONSTANT

The bacteria levels in both the Merrimack and Souhegan Rivers have changed very little since they were tested two weeks ago and have showed slight improvement since the beginning of August. The latest test was performed on Tuesday, September 14. This was the last test for the season done by volunteers from the Souhegan Watershed Association (SWA) and Merrimack River Local Advisory Committee (LAC). The tests are being done to establish baseline data for the health of the river, but one of the tests – for E. Coli bacteria – indicates how healthy the water is for humans.

Generally the Souhegan had acceptable bacteria levels in most of the places where children swim or play near the river. And that has also been true most of the season. One exception is the popular swimming hole at the Boston Post Road bridge in Amherst. Counts there have improved over the last month, but are still higher than acceptable for public swimming. The count there this week was 200. Bacteria levels above 88 are considered unsafe for public swimming areas because they may cause ear and eye infections, diarrhea or other gastrointestinal problems among some of the swimmers. Boston Post Road has not had an acceptable test there in two years and the town has advised children not to swim there.

Tests bracketing the Greenville Wastewater Treatment Plant showed a huge increase and seem to indicate an unacceptable level of pollution coming in from the plant. This has not been a problem in the past and may indicate a mechanical malfunction at the plant.

The Merrimack River between Manchester and Tyngsborough had acceptable levels at each of the nine sites monitored. Again this has been true for most of the season. The Merrimack is now a very clean river as far as bacteria is concerned. The river was considered one of the dirtiest rivers in the country 25 years ago when the Clean Water Act was enacted. Secondary treatment wastewater plants were built and the river has cleaned up considerably. A second phase of the cleanup is going on now. Both Manchester and Nashua dump raw sewage into the river when heavy rainstorms overwhelm the combined single sewer/stormdrain pipe. But they are both digging up streets and putting two pipes into the ground to separate sewers and stromdrains.

The test on Tuesday came four days after the heavy rains from Hurricane Dennis. Monitors expected to see higher bacteria counts than normal, but just the opposite was true. The river had cleaned itself in the four intervening days since the last rain.

August 31st results
RIVER BACTERIA COUNTS CONTINUE TO IMPROVE

Tests performed by the Souhegan Watershed Association (SWA) and Merrimack River Local Advisory Committee on August 31 indicate a continuing of the improvement that was first seen in tests two weeks ago. The E. Coli bacteria counts on both the Souhegan and Merrimack Rivers are generally lower than they were two weeks ago and the tests two weeks ago were lower than at the beginning of the month. “August has been a good month for people using the Souhegan or Merrimack but poor for the fish in the rivers,” said George May, president of the SWA.

Even the worst spots on the Souhegan have improved to the point that there is little worry about swimming in the river. The highest bacteria count at any of the usual swimming holes was 170 at the Boston Post Road Bridge in Amherst. That is higher than the acceptable level of 88 but the lowest it’s been since the beginning of June and well down from 610 at the beginning of August. Bacteria levels above 88 are considered unsafe for public swimming areas because they may cause ear and eye infections, diarrhea or other gastrointestinal problems among some of the swimmers. Boston Post Road has not had a single acceptable test there in two years and the town has advised children not to swim there.

Weston Park at the Turkey Hill Bridge in Merrimack, another spot where children swim, also had a reading higher than 88. The level there was 160. But this area has had generally acceptable levels all summer according to May.

The areas in Amherst, Milford and Greenville that have been concerns also improved in the latest bacteria tests. A test site upstream of Greenville Mill Pond, a site that may have been polluted by manure being spread too close to the Souhegan, now has a count of 37. This is the second consecutive acceptable test for this site. “Tests of various sites in Milford and Amherst are still higher than 88 but well below what they were a month ago,” said May.

None of the sites on the Merrimack River tested higher than 88. With few exceptions none have tested high all summer long. “The Merrimack, which was one of the ten most polluted rivers in the United States 25 years ago, is now completely safe for swimming in the test area between Manchester and Tyngsborough,” said May. “The only time there is a concern now is after a heavy rain when raw sewage is discharged into the river through storm drains in Manchester and Nashua – and in a few years that won’t be a problem.” Both Manchester and Nashua are in the process of digging up their streets and separating storm drains and sewer pipes. The process will take ten years to complete in Manchester and 20 years in Nashua.

“What’s good for humans, however, doesn’t necessarily translate to the fish,” said May. Dissolved oxygen counts in both rivers is very low, water temperatures are up, and the level of the water Souhegan is very low. “In many places one can walk across without getting your feet wet,” said May.

August 17th results
BACTERIA COUNTS IMPROVE ON LOCAL RIVERS

Tests performed by the Souhegan Watershed Association (SWA) and Merrimack River Local Advisory Committee on August 17 indicate generally more acceptable levels of bacteria on the Souhegan and Merrimack Rivers than have appeared recently.

George May, president of the SWA, said that the E. Coli bacteria counts all along the Souhegan and on the Merrimack between Manchester and Tyngsborough seem to have improved since the last test two weeks ago. “Perhaps the recent light rains and more moderate temperatures have helped improve the health of the rivers,” explained May. He cautioned, however, that the improvements were relative. “Those sites that have been a problem all season continue to have unacceptable levels even though they have improved,” he said. The swimming hole at the Boston Post Road Canoeport in Amherst had a reading of 170 on Tuesday. This is down from 610 two weeks ago. But the acceptable level for public swimming areas is 88. Bacteria levels above 88 are considered unsafe for public swimming areas because they may cause ear and eye infections, diarrhea or other gastrointestinal problems among some of the swimmers.

ll of the other usual swimming areas on both the Souhegan and the Merrimack had very acceptable levels. The Horseshoe in Wilton was 34; Weston Park at the Turkey Hill Bridge in Merrimack was 21; Indian Ledges in Merrimack was 10, and everywhere on the Merrimack tested well below 88.

Areas that were being watched all improved. The Souhegan River upstream of Greenville Mill Pond has had several bad tests recently, but this week tested at 74, down from several tests that were over 400. It was thought that manure spread on a field near the river had leached into the river some time ago. The pond now is very low; the water level has dropped about four feet during the summer.

The Souhegan as it meanders through Amherst has tested for very high E. Coli counts all during the summer, but this week this stretch improved. "The levels are still unacceptable, but they are better. Instead of levels in the 400s we now have levels in the 200s, but that’s still too high for a clean river,” said May.

Again volunteers found the Merrimack River to be extremely clean. The Merrimack has tested at very acceptable levels throughout the summer. The only time bacteria levels seem to go up on the Merrimack is after a heavy rain when the river near Manchester and Nashua receives raw sewage that overflows from the wastewater treatment plants there. And this year there haven’t been many heavy rainstorms.

August 3th results
BACTERIA LEVELS REMAIN CONSTANT

E. Coli bacteria counts taken on Tuesday, August 3, continue the pattern seen on the Souhegan and Merrimack Rivers so far this season. Seven of the sites tested on the Souhegan were OK; ten were not. Six of the seven sites on the Merrimack between Bedford and Tyngsborough tested OK.

Swimming holes on the Souhegan at Indian Ledges in Merrimack and the Horseshoe in Wilton were both well below standards for swimming. They have both tested fine all season. The Canoeport at Boston Post Road in Amherst, however, tested very high, and for the first time this season Weston Park at the Turkey Hill Bridge in Merrimack exceeded acceptable standards for swimming. Boston Post Road tested at 610 this week. It has increased from 100 to 150 to 190 to 270 in earlier tests this season. The town has posted a “Swim At Your Own Risk” sign at this site. Bacteria levels above 88 are considered unsafe for public swimming areas because they may cause ear and eye infections, diarrhea or other gastrointestinal problems among some of the swimmers. The reading at Turkey Hill Bridge in Merrimack was 220.

The SWA has been watching E. Coli counts taken just above Greenville Mill Pond on the Souhegan. Tests there indicate a pollution problem. The thinking is that manure spread on a farm field is leaching into the river. The reading here was 442 for the second test in a row.

The Merrimack River is very clean, according to Joanne King, coordinator of the monitoring program. “All summer long we’ve had good test results from the Merrimack,” said King. “The only spot we’re watching right now is in the area above the Depot Street boat ramp in Merrimack. This is an impact site for the Derry Wastewater Treatment Plant which dumps treated water into the Merrimack. We’ve had two consecutive bad readings here. The count was 140, down from 692 two weeks ago,” said King.

July 20th results
RIVER BACTERIA LEVELS UNCHANGED

"The high E. Coli counts on July 20th are probably due to a combination of drought conditions and high water temperatures combined with the resulting runoff from a rainstorm the day before our sampling date," according to Joanne King, coordinator of the volunteer water quality monitoring project of the Souhegan Watershed Association (SWA) and Merrimack River Local Advisory Committee (LMRLAC), the organizations responsible for testing on the two rivers.

“Generally bacteria levels throughout both watersheds increased from two weeks ago, but there are pockets of good news too,” said King. “The usual swimming holes on the Souhegan, except for Boston Post Road, remained in good shape -- Weston Park at the Turkey Hill Bridge and Indian Ledges in Merrimack and the Horseshoe in Wilton have not had a bad test all season long. And the Merrimack River continues to be in relatively good condition with only a few exceptions probably attributable to the rain.”

“Generally bacteria levels throughout both watersheds increased from two weeks ago, but there are pockets of good news too,” said King. “The usual swimming holes on the Souhegan, except for Boston Post Road, remained in good shape -- Weston Park at the Turkey Hill Bridge and Indian Ledges in Merrimack and the Horseshoe in Wilton have not had a bad test all season long. And the Merrimack River continues to be in relatively good condition with only a few exceptions probably attributable to the rain.”

“High levels of bacteria would be expected on the river in town centers and tests bore out this expectation. Downtown Greenville had the highest reading we’ve seen at 950. The SWA is still seeking causes and corrections for the high readings found this year around Greenville.” according to King.''We're investigating several areas of possible point source pollution entering the river above and below Greenville where agricultural run-off and a suspicious pipe may be sources of unexpectedly high E.coli counts and phosphorus levels."

“Milford center levels are also very high – above 400 throughout the testing area. Downtown Wilton, however, seems reasonably clean,” said King.

“High bacteria levels on the Merrimack above Depot Street in Merrimack and approaching the state line in Tyngsboro are aberrations and will be closely watched on our next test on August 3,” she said.

Mrs. King also noted that another of the tests the volunteers do is for dissolved oxygen and that levels are going down. Dissolved oxygen is critical for the wellbeing of fish and other water organisms. "Probably because of the recent high temperatures and very low water levels, dissolved oxygen is reaching a critical low level where cold water fish species such as trout and salmon may begin to suffer ill effects," she said.

July 6nd results
RIVER BACTERIA LEVELS UNCHANGED

Water quality testing on the Merrimack and Souhegan Rivers showed relatively few changes in bacteria levels from two weeks ago. "For the last month we have seen only very slight increases in E. Coli bacteria counts on both the Souhegan and Merrimack Rivers, no significant changes in general." according to George May, president of the Souhegan Watershed Association (SWA) and Merrimack River Local Advisory Committee (LMRLAC), the organizations responsible for testing on the two rivers.

Joanne King, coordinator of the testing program for the SWA and LMRLAC released the test results for samples taken on July 6. "They show a continued high count for the Amherst section of the Souhegan, especially at Boston Post Road. But we saw considerable improvement at two sites we were watching. Stoney Brook in Wilton and Greenville Mill Pond in Greenville both came down to acceptable levels for bacteria. We expect that the DO (dissolved oxygen) test will confirm a pollution discharge in Stoney Brook two weeks ago that is gradually clearing up," said Joanne King. The high counts seen at Greenville Mill Pond a month ago were attributed to manure that was spread too close to the river.

King noted that the usual swimming holes in Wilton and Merrimack all tested at an acceptable level with the exception of the Amherst Canoeport at Boston Post Road. Boston Post Road has not tested at an acceptable level so far this year or last year. The town has posted a "Swim At Your Own Risk" sign at this site. "A month ago the bacteria level was 100; two weeks ago it was 150; this time it tested at 190," said King. Bacteria levels above 88 are considered unsafe for public swimming areas because they may cause ear and eye infections, diarrhea or other gastrointestinal problems among some of the swimmers.

"The Merrimack River continues to be a real success. We’ve been getting very low bacteria counts all the way from Bedford to the Massachusetts border all summer long," said King.

June 22nd results
RIVER BACTERIA LEVELS UNAFFECTED
BY LACK OF RAIN AND LOW WATER

Water quality testing on the Merrimack and Souhegan Rivers showed relatively few changes in bacteria levels from two weeks ago. In spite of the low ater levels from lack of rain and warm temperatures in the last two weeks, E. Coli counts remain about the same, according to George May, from the Souhegan Watershed Association (SWA) and Merrimack River Local Advisory Committee (LMRLAC), the organizations responsible for the testing on the two rivers.

"We continue to see higher levels of bacteria at the Amherst Canoeport than we would like, but they are only marginal, and all the other swimming holes test fine," said May. The Amherst Canoeport on Boston Post Road near the high school is a popular swimming hole for local kids. It has had consistently higher than acceptable bacteria levels for the last couple of years. The town has already posted a "Swim at your own risk" sign againthis year. The count there taken on Tuesday, June 22, was 150. This is up from 100 two weeks ago. Bacteria levels above 88 are considered unsafe for public swimming areas because they may cause ear and eye infections, diarrhea or other gastrointestinal problems among some of the swimmers.

"Swimming holes at Turkey Hill Bridge and Indian Ledges in Merrimack and the Horseshoe in Wilton and everyplace on the Merrimack River all tested OK," said May. Seventeen sites on the Souhegan and nine sites on the Merrimack between Bedford and Tyngsboro are tested on a biweekly basis by volunteers trained by the SWA. "The Merrimack River is a real success story. We’re getting very low bacteria counts from all the sites right now."

"We’re particularly pleased to see that the levels above Greenville Mill Pond are going down." Two weeks ago the level was over 400, and the count now is 103. "We’ve gotten reports that a field a short distance upstream that has no vegetative buffer to the river had been spread with manure and that accounts for the high counts," said May. "We hope to get that problem corrected," he said. Another problem continues to be high counts on the Souhegan as it flows through Amherst. "We still have not identified the causes there, but we will eventually," he said.

The count on Stoney Brook rose drastically from two weeks ago. On June 8 the count was 10, very low. On June 22 it went to 270, very high. "We’ll be watching this area on our next test," said May.

June 8th results
WATER TESTING ON SOUHEGAN AND MERRIMACK BEGUN

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 third summer that the groups have collected data on water quality on local rivers. Eighteen sites on the entire length of the Souhegan are being monitored. Nine sites on the Merrimack between Manchester and Tyngsboro are monitored.

One of the tests being performed is for E. Coli bacteria. Bacteria levels above 88 are considered unsafe for public swimming areas and may cause ear and eye infections, diarrhea or other gastrointestinal problems. 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 last year’s results are also available on the SWA website, www.ultranet.com/~harts/swa. It should be noted that rainstorms between testing dates will probably raise bacteria levels as shoreland runoff carries bacteria into the rivers.

The first tests, done on June 8th, indicate generally acceptable bacteria levels on both rivers in spite of very low water levels. Two swimming areas at Turkey Hill and Indian Ledges in Merrimack were well below 88. The Horseshoe in Wilton tested at 52. The Canoeport at Boston Post Road in Amherst tested at 100, slightly higher than acceptable. The Boston Post Road area is a very popular swimming hole and it normally tested at higher than acceptable levels for bacteria most of last year also. The Town of Amherst closed the area to swimming and posted advisory signs there last summer.

The Merrimack River has been a much cleaner river than the Souhegan in past years’ tests. Again this season the tests continue to show very low bacteria levels in the Merrimack. It is only during rainstorms, when untreated sewage from Combined Sewer Overflows (CSOs) in Nashua flow directly into the Merrimack and Nashua Rivers, that bacteria levels become dangerous to humans.

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