Dam Update: What's Happening At the Foster's Pond Dam
Chairperson: Paul Ross
Members: John Lugus, Arno Minkkinen, Becci Backman, Max McNeil, Maureen Keller, Rich MacDonald, Rick Davis, Dave York, and Dave Brown.
Late-April Showers Raise the Pond As Drawdown Ends (4/08)
Late-April Showers Raise the Pond as Drawdown Ends
April 2008
As the region basked in day after day of unseasonably warm, dry weather, the Spring refill of Foster's Pond began - but slowly. Then came a two-day stretch of torrential rains, and water levels climbed.
April 22: The first stoplog was inserted in the dam's sluiceway on April 19. Three days later, when this picture was taken, rising water was beginning to splash over the top. The second stoplog went in the following day. The first of three stoplogs - the 10-inch-high boards which are used to control water levels in the Pond - was inserted in the narrow sluiceway of the dam on April 19.
The refill marks the end of the annual 18-inch Winter drawdown, a safety measure which gives the Pond additional capacity to absorb Spring's snowmelts and the run-off occasioned by heavy rains falling on saturated soil in the watershed.
The pace of the refill depends on the weather. With little rain, springs and streams feeding the Pond will still raise the water level, but not very fast. And gaps are purposely left between the stoplogs during the refill, so that water is always flowing into the downstream wetlands.
Within three days of insertion of the first stoplog, the Pond had risen a couple of inches, enough for water to start trickling over the top of the board.
The second stoplog was inserted on April 23. But with lower-than-normal rainfall, and dry air causing evaporation, the pace of the refill was much slower than the inch or so a day normally expected at this time of year.
Not to worry, however. A heavy rain can cause the Pond to rise several inches in one night. And by month's end, that's just what happened. In a 30-hour period April 28-29, 2.1 inches of rain - as measured at the Foster's Pond weather station - poured down, and even before the last storm had blown through, the Pond had risen another six inches.
Too much rain is more of a hazard to the dam than too little. The Mother's Day flood of 2006, which came
just after that year's refill, caused significant damage to the dam - though the work that has been done over the last year significantly reduces the likelihood that the dam will again be overtopped.
April 23: Six tons of boulders have been placed at the foot of the dam, in the stilling basin. The aim is to break the force of water pouring over the spillway and prevent scouring, which could weaken the foundation of the dam. The balmy weather and the new "pocket park" at the dam have proved a winning combination for area residents. Whether for a young couple sitting hand in hand on the bench, or dads bringing youngsters to angle for sunfish, the dam is proving to be a tranquil and convenient spot for enjoying the Pond.
The newly-planted grass on the dam is getting some professional help this year. The Corporation has lined up Organic Soil Solutions, an organic lawn care company based in Woburn, to tend the grass in an environmentally sound way. The company is donating its services. (For more information on landscaping your own Pond-side property, read Lawns and Landscapes in Your Watershed, a publication of the State Department of Environmental Protection.) The grass has already received a dose of corn gluten (a natural weed suppressant and fertilizer) and an overseeding on bare spots.
Volunteers have done some additional maintenance work on the dam this Spring. As recommended by the Corporation's consulting engineers, the volunteers placed stones in the stilling basin at the foot of the dam. The aim is to dissipate the force of the water coming over dam and prevent scouring, which eventually could undermine the structure. About six tons of stones have been heaved by hand, one at a time, in the effort.
Engineers will conduct a second inspection of the dam in early May. Their first inspection, in November, 2006, rated the dam as being in "poor" condition and led to a year of extensive volunteer labor to correct deficiencies.
Pond and Temperatures Drop as Winter Sets In
December 2007
The Pond tamely followed the script for the annual winter drawdown, falling by early December to the target level ofabout 18 inches below the spillway of the dam. Just in time. Someone gave an early cue to Old Man Winter.
December 18: The winter drawdown has lowered the Pond about 18 inches below the dam's spillway. Frigid temperatures and serial snowstorms blanketed the area with mixtures of snow and ice. A new weather station on Foster's Pond recorded low temperatures of 20 degrees or below on 17 of the first 19 days of December. And only one of those days - December 12 - yielded an average temperature above freezing for the day.
State wildlife officials like to see a winter drawdown attain the low water mark before freezing weather sets in. That gives water-dependent animals a chance to adjust their burrows, move to deeper water, or do whatever else they do to prepare for winter before everything ices up. So the timing of this year's drawdown was by the book.
Meanwhile, the snow just kept on coming. And coming. Around two feet fell before the first day of winter, turning the Pond into a picture postcard. Indeed, one mother posed her family on the dam's new bench for their annual holiday picture.
December 18: Foster's Pond Dam blanket by the early snows. The drawdown was made for just such weather. Freezing temperatures will kill fanwort growing along shorelines that have been exposed by lowering the Pond. And, with the drawdown, the Pond has greater capacity to handle snow melt and spring rains without the danger of overtopping the dam.
With Restoration Complete, Drawdown Begins
November 2007
The 2007-2008 winter drawdown of Foster's Pond began November 4, with water cascading through the narrow sluiceway of the 150-year-old dam. With the Pond already several inches below its normal level for this time of year, the drawdown will bring the water down another foot or so over the next three weeks.The annual drawdown increases the Pond's capacity to hold winter snows and spring run-off, and is aimed at averting
a repeat of "overtopping" - when so much water comes over the dam that the flow cannot be contained within the concrete-lined spillway. Overtopping can seriously erode an earthen dam, and is the leading cause of catastrophic failures in such structures.
November 4: The 2007-8 winter drawdown begins. Two "stop logs' have been removed from the sluiceway. The third will come out later. This is the third winter drawdown in as many years, part of a new regimen of lake management undertaken by the Foster's Pond Corporation, which owns the historic dam. The drawdowns, authorized by a comprehensive Order of Conditions approved by the Andover Conservation Commission, dovetail with other efforts by the Corporation to control nuisance vegetation and safeguard the ecology of the Pond.
This year's drawdown marks a major milestone in the protection of the dam, which impounds the 120-acre Pond. A year-long project to restore the dam - and turn it from a weed-entangled near-ruin into a community icon - has ended, with residents marveling at the transformation.
The dam is now far safer, with both sides of its 12-foot-wide spillway - the picturesque waterfall that carries the flow when the Pond is at its normal level - now buttressed on both sides with granite-block walls. The crest has been restored to a uniform height, with the addition of tons of clay to fill sinkholes that had developed over the years. And a new blanket of grass now covers the entire crest, replacing both the trees that sank leak-inducing tap roots into the crest and the poison ivy which discouraged maintenance.
October 31: The crest of the Foster's Pond Dam, now safely buffered by granite walls and crushed stone, offers a serene "pocket park" for residents and visitors. At the behest of engineers who inspected the dam last year, the Corporation has also restored an emergency spillway, which will allow flood waters to flow harmlessly to the side of the dam instead of over the top. The spillway will see action only in the highest of flood conditions - it will carry water only if the Pond comes up to within a foot or so of the top of the crest - but provides what could be a dam-saving relief valve in a full-blown hurricane.
The restored dam now serves a dual purpose. With the safety improvements, which include an accessway
allowing construction equipment to reach the crest when needed for maintenance or in an emergency, the dam is now easily accessible, and visitors from near and far have come to launch boats (gasoline powered motors are not allowed, but canoes, kayaks, and boats with electric motors are welcome), fish from the shoreline, or just sit and enjoy the view. The Corporation has installed a granite bench for the enjoyment of visitors to the new "pocket park."
Visitors can now walk easily to the crest of the dam. The emergency spillway (left of the bench) doubles as a launch ramp for canoes, kayaks, and boats powered by electric motors. Gasoline-powered engines are prohibited. Most of the work over the past year has been performed by volunteers, most notably Scott Fumicello, a resident mason and landscaper, assisted by FPC president Steve Cotton. The scope of the work was defined by the Corporation's engineers, GEI Consultants, Inc., of Winchester. The site plan was drawn by designer Dave Brown, a Glenwood Road resident. Many other volunteers contributed time and effort, including Dam Committee Chairman Paul Ross, Foster's Pond Road resident Will Weightman, and Rattlesnake Hill Road resident Steve Zappala.
On the crest of the dam, the new granite bench affords a serene vista of Foster's Pond. Rock Island, the only Town-owned island in Andover, is barely visible under the sloping tree to the left of the bench. Significant funding for the effort came from the Boston Foundation, which administers the Bessie Goldsmith bequest and owns the Goldsmith Woodlands, the largest property abutting the Pond. Recognizing that the magnificent shoreline views from the Goldsmith reservation depend on a healthy Pond, the Boston Foundation has been a major supporter of the Foster's Pond Corporation's efforts to protect and manage Foster's Pond.
Local companies, including Deloury Industries and Ferris Tree Service, also donated materials to the dam project.
Some finishing touches remain to be done. Additional boulders will be added to the stilling basin below the spillway, breaking the force of the waterfall to minimize erosion under Rattlesnake Hill Road.
And the Corporation is trying to raise money to erect a permanent sign at the site, replacing the temporary signs now posted on wooden stakes. The new sign will present information on the history and ecology of the Pond, as well rules for a safe visit.
Bench Added to New 'Pocket Park'
September 2007
A granite bench now adorns the new "pocket park" which is emerging on the crest of the Foster's Pond Dam.Topped by an old slab bearing marks from the days before quarries had saws, the bench affords visitors a surprisingly comfortable spot from which to gaze at the tranquil vista of the Channel and Rock Island.
The bench, with its graceful proportions, exhibits the artistic flair of its creator, Scott
Fumicello, the Willard Circle mason and landscaper who has donated countless hours to the restoration of the 150-year-old dam. Fumicello was honored for his work at the Foster's Pond Corporation's summer meeting in August.
September, 2007: The new bench affords a tranquil view down the Channel. Granite for the bench was donated by Foster's Pond Road residents Dave Adilman and Lisa Walters.
Almost all of the work on the dam has been purely functional, the result of recommendations from the Corporation's engineer last year to prevent further overtopping. That's the term for high water exceeding the capacity of the dam's spillway and cascading over its earthen crest. The result is erosion which can threaten the catastrophic failure of an earthen dam.
With the crest on both sides of the spillway now restored, and armored by granite blocks, geotechnical fabric, and crushed stone, overtopping and erosion are much less likely. The treeless grass expanses on the crest are also designed to minimize erosion that can result from water penetrating around the woody roots of trees and bushes. And the large swale sweeping around the easterly crest of the dam is also a safety feature - an emergency spillway that will allow flood water to escape without overtopping the dam in the highest water conditions.
Many of these safety features contribute to the park-like appearance of the newly restored dam. The Corporation has opened the inviting new "pocket park" to visitors from near and far, allowing the crest to be used for fishing and the emergency spillway to double as a launching ramp for canoes, kayaks, and boats with electric trolling motors.
Litter has actually decreased at the dam since it has been opened to the public, and Foster's Pond is burnishing its reputation as a destination for serious anglers in search of feisty - and weighty - large-mouths. The anglers come from as far away as Fitchburg and New Hampshire, as well as from residences down the street. Parking is not allowed at the dam, but visitors have found on-street parking near-by. Visitors are asked to be particularly careful to stay off lawns and leave no litter behind.
Dam's East Side Nears Completion
August 2007
August 31 : The easterly crest of the dam reveals its finished contours. The crushed stone embankment and new granite wall protect the dam from erosion. The granite slabs just visible at the top of the photo will be used for a bench. The easterly crest of the Foster's Pond Dam is showing its finished contours, as the Corporation's year-long project to restore the historic structure edges toward completion.
The majestic easterly arc of the earthen dam has been restored to a height that will withstand overtopping, the major threat to dams of this type. Clay has been added to the Pond-facing slope, covered with a geotechnical fabric to keep it from washing away, and further protected from erosion by a layer of crushed stone. The top has been loamed, and will be seeded with grass, the best protective cover for earthen dams.
The restoration work (above) will prevent a repeat of the May, 2006, overtopping (right), when volunteers spread a makeshift barrier to slow erosion of a sinkhole on the easterly crest. And an important safety valve has been restored. At the direction of the Corporation's engineers, the original emergency spillway - a gully at the eastern edge of the dam - has been cleared out. The gully looks to most visitors like a boat ramp, and, indeed, boaters are invited to use it; it has been rebuilt with a lot of stone at its mouth, to minimize erosion from the launching of canoes, kayaks, and bass boats. But the real purpose of the contour is to allow flood waters to escape, without eroding the dam, in the rare storm which causes the Pond to rise to within a foot of the dam's crest.
There is still some heavy work to be done. The stilling basin, just below the dam's picturesque waterfall, has been scoured out over the decades. When water flows heavily over the dam, the basin turns into a frothing cauldron, and the turbulent water erodes the stonework under Rattlesnake Hill Road. The engineer's recommended solution: add boulders to the stilling basin and against the face of the dam, so that water pouring over the dam breaks on the rocks instead of roiling in a pool. That work is now underway.
Then there are the finishing touches - construction of a bench to provide visitors a place to sit and contemplate the view, seeding the crest with a grass cover, and finishing the slopes and the area in front of the dam with wood chips.
Volunteers are also working on a plan for a sign to provide visitors with information on the history and ecology Foster's Pond.
West Side of Dam Is Almost Finished
July 2007
July 25: The westerly crest of the dam, with a new grass cover atop tons of clay added to the cap. The new granite wall and crushed stone facing the Pond, are expected to prevent erosion and overtopping which periodically threatened the dam.
Fall, 2004: Before the Corporation undertook to rehabilitate the dam, this is what the westerly crest looked like. Raking and weed treatments have also cleared aquatic vegetation. The westerly crest of the Foster's Pond Dam - for decades its most vulnerable spot - is now almost fully rehabilitated. It's lowest portion, frequently overtopped with torrents which threatened to erode the 150-year old earthen structure, has been raised nearly three feet and armored with granite blocks. Tons of new clay along the 75-foot westerly crest are protected by a facing of crushed stone, and the crest itself - once a tangle of trees, brush and poison ivy - now sports a cover of just-sprouted drought-resistant grass.
Volunteers will now focus on the easterly crest, which will mirror the new look.
Work Progressing On Dam
July 2007
Major progress has been made at the dam, with the westerly side nearing completion. On July 15, loam was spread on half the dam, showing the final contours of the portion that had in past years proved most vulnerable to overtopping.
July 15: Scott Fumicello uses his Bobcat to smooth new layer of loam on the westerly crest of the dam. The stone work has now been completed, with new granite-faced walls guarding each side of the spillway. For decades, State dam inspectors had complained that the dam's shallow, concrete-lined spillway was inadequate to handle the flow of water during occasions of normally heavy flow. With the new work, that problem has been solved.
Most of the recent work on the dam has been spearheaded by Willard Circle resident Scott Fumicello, an expert mason and landscaper who has donated time and equipment to the massive effort.
Foster's Pond Road resident Will Weightman, who maintained the dam almost single-handedly for many years, contributed a nifty solution for keeping unauthorized vehicles off the dam: he drilled a pair of anchors into the large boulders flanking the new pathway to the crest of the dam, allowing a chain to be strung across the access-way.
Grass seed was spread on the westerly crest July 17, and will be watered through 375 feet of newly-acquired hose running from the Rattlesnake Hill Road home of Dam Committee Chairman Paul Ross. Using Pond water for irrigation isn't possible this year because it contains the low concentrations of herbicide being used to treat fanwort.
The focus will turn now to the easterly side of the dam. Work is well underway to backfill the new wall with clay, bringing the easterly crest up to the same height as the western side. The easterly crest, too, will be faced with crushed stone and topped with loam. Final plans call for a granite bench and an informational sign to be added to the "pocket park."
But even unfinished, the dam is proving a popular draw. On July 15, a young visitor from Haverhill caught his very first fish there - a two-and-a-half-pound largemouth bass. After posing with his captor for a picture, the bass was allowed to return to the Pond.
2006-7 Winter Drawdown Ends Quietly
May 2007
The winter drawdown of 2006-2007 came to an end on May 22, as the third stop log was inserted into the dam. With the Pond at its "normal" level for this time of year, water flowed briskly over the dam's spillway, presenting the picture-postcard scene that has drawn visitors for 150 years.Drawdown Inches Towards a Gentle End
May 2007
Mindful of last year's destructive May flood, managers of the Foster's Pond Dam are bringing this year's Winter drawdown to a slower end. They are keeping the water level a few inches below the lip of the dam's 12-foot wide spillway, giving the Pond some extra capacity to absorb a large storm like the one which last year sent water surging over the crest of the dam.
May 1: Water trickles through the sluiceway after a second "stop log" slows the outflow from Foster's Pond. The water level is expected to climb slowly - unless there's a major storm. Three boards called "stop logs" - inserted in the narrow sluiceway adjacent to the dam's main spillway - control the water level. When all are removed to draw the water level down for the winter, the Pond level can be dropped about 18 inches below the lower lip of the spillway. The first stop log was reinserted on April 22. The second went in on May 1. How fast the water level rises depends on the weather. In April, with the ground saturated from earlier rains, a three-inch storm raised the water level by one foot overnight.
The dam is in much better shape to withstand flood conditions than it was last year. The sinkholes caused by last year's flood have now been repaired, and both sides of the spillway have been significantly raised. The westerly side of the dam is nearly finished, awaiting only a coating of loam and seeding with drought-resistant grass. The easterly side is slated for considerably more work.
Torrential Rains Test Drawdown and New Wall
April 2007
With weather reports warning of torrential rains from an impending nor'easter, volunteers ignored blustery winds during a two-day pre-storm push to strengthen the most flood-prone sectionof the Foster's Pond Dam.
April 16: The new wall fortifies what had been the lowest point in the dam. Note the water level, near the lip of the spillway. Two days earlier, the water was a foot lower. On April 13 and 14, a dedicated work crew wrestled granite slabs into place, completing a gracefully curving wall along the westerly side of the sluiceway and raising a vulnerable low area some 20 inches. They backfilled the wall with 20 tons of clay, eliminating a large sinkhole created during last May's flooding. Their efforts leveled the crest of the dam, which had dipped markedly in the area near the sluiceway. The dam is now much less likely to be overtopped when the Pond rises.
A similar wall will be constructed on the easterly side of the dam. When the work is completed, loam will be spread along the crest, which will be seeded with a grass cover. The upstream slope of the crest will be lined with a layer of clay, covered by a protective fabric weighted with crush rock. The sloping face of the crest south of the sluiceway received some of this treatment during the two-day effort, which was led by Willard Circle resident Scott Fumicello, a professional mason. He was joined by Rattlesnake Hill Road resident Steve Zappala, Dam Committee Chairman Paul Ross, and Steve Cotton.
This crucial phase of the work was completed just in time. On April 15, Mother Nature delivered torrential rains on the predicted schedule, dumping some 3 inches in less than two days. By 4 p.m. on April 16, the Pond had risen about a foot, and was a fraction of an inch below the lip of the dam's main spillway. That was an astonishingly fast rise. Normally, it takes about a month to refill the Pond after the Winter drawdown. This mid-April storm refilled the 120-acre water body overnight. And that occurred with all of the "stop logs" out of the sluiceway, allowing maximum drainage the entire time.
Last year, the Pond had been refilled by May 1, leaving no room for the deluge which flooded New England two weeks later. This year, the Corporation postponed the refill, allowing workers to repair the dam during early April - and maintaining the Pond's capacity to absorb Spring floods. That strategy worked.
Work Resumes on Dam
April 2007
A small crew of volunteers took advantage of a sunny early-Spring week-end to fortify the lowest section of the dam against overtopping, which eroded parts of the dam last year.Guided by Willard Circle resident Scott Fumicello, a professional mason who has played a major role in the dam repair
project, the volunteers excavated sink holes, lugged granite slabs, and poured concrete, building a wall which will raise the height of the crest and armor it in the event of high water.
This new wall will protect a part of the dam that was eroded in the May 2006 flooding. The finished wall will be about one foot higher. The granite for this phase of the work was salvaged from the dam itself. The slabs had been buried in soil along the crest decades ago, but subsequent layering of clay and sand had left them serving no function.
The work over the March 31-April 1 week-end is part of a remedial plan developed by engineers hired by the Corporation to inspect the dam last year. When the project is completed, granite-faced walls will keep floodwaters within the area of the concrete-lined spillway, instead of flowing over the erosion-prone earthen crest. In extreme flooding conditions, an auxiliary spillway will carry excess waters to Rattlesnake Hill Road, preventing any threat to the stability of the dam.
Inspection Report: Dam Needs Some Work
December 2006
Concluding that the Foster's Pond Dam is in "poor" condition, engineers hired by the Foster's Pond Corporation to inspect the 150-year-old structure have laid out a to-do list to remedy "deficiencies " and "improve the overall condition of the dam."The findings and recommendations are contained in a 58-page report submitted to the FPC on December 13 by GEI Consultants, Inc., of Winchester. Copies of the report have been filed with the State's Office of Dam Safety, which earlier this year had ordered more that 1,000 dam-owners in Massachusetts to hire engineers and complete similar inspections by December 15. Two GEI engineers conducted the inspection - the first in more than five years, and the most thorough in nearly 100 - on November 10.
The GEI recommendations, which the report characterized as a combination of "maintenance" and "minor repairs", include:
- Filling sinkholes and restoring the crest of the dam to a consistent elevation, armoring the upstream embankments
for 25 feet on either side of the spillway and sluiceway, and planting a grass cover on the crest to prevent erosion;
This sinkhole near the sluiceway is one of the areas in need of repair. - Removing stumps and root systems where possible from the crest of the dam;
- Restoring the auxiliary spillway, which was originally intended to relieve the dam during flood conditions but has for years been barely visible as a shallow gully about 75' east of the dam; and
- Adding rocks to the stilling basin - the pool between the dam and Rattlesnake Hill Road - to buttress the foot of the dam and dissipate the force of water plunging over the dam's picturesque waterfall.
GEI's report estimated the cost of the work it recommended at between $21,000 and $42,500, but FPC President Steve Cotton, after conferring with the engineers, called those numbers "an unimaginably worst-case scenario," and said an estimate of $5,000 to $7,500 was "a lot more likely." He said his estimate was based on the FPC's ability to recruit volunteers to do most of the work.
Some of the work recommended by GEI has already started, based on the preliminary recommendations made by the engineers at the time they conducted their inspection in November. Volunteers have felled trees and brush the length of the dam, and the largest sinkhole on the crest has been partially repaired. The Corporation is trying to procure granite slabs to armor the crest and prevent the kind of erosion which hit the dam during last May's flooding.
To download the essentials of the GEI report (the text and a site sketch, 7 mb), click here.
To download the entire report (including pictures and charts, 20 mb), click here.Balmy Weather Aids Dam Repairs
December 2006
Taking advantage of unseasonably warm November weather, volunteers have begun the repair work recommended by engineers who conducted a safety inspection the Foster's Pond Dam earlier in the month.The maintenance work has already given a new look to the 150-year-old structure, creating visitor-friendly access to the shoreline and eliminating a tangle of brush and trees at the crest of the dam.
May's overtopping (left) scoured an area next to the spillway. A hastily-improvised fabric barrier slowed the damage. In November, repairs got underway (above). Volunteers felled several trees growing on the dam. The engineers had asked for the trees to go, since their roots can provide channels for water to leak through an earthen dam.
On November 1, when the drawdown began, water came nearly to the top of the sluiceway.
By December 1, the water level had dropped about 15 inches, allowing work to begin on the dam. Then, on November 30, work began to repair damage caused by last May's flooding. Willard Circle resident Scott Fumicello, a skilled mason who has done extensive volunteer labor on the dam, set in place a foundation of granite cobblestones as part of a plan to build up an area adjacent to the main spillway that was overtopped and badly scoured last May.
The work was aided by balmy weather which held as the winter drawdown dropped the water level sufficiently to allow access to the damaged area. The drawdown, which began November 1, brought the Pond down more than a foot below the level of the spillway. One reason for lowering the Pond each winter is to allow repairs to be made at the dam.
Engineers Inspect Dam
November 2006
The Foster's Pond Dam got its first thorough check-up in five years, and after being probed, peered at, and photographed for several hours, the experts tentatively concluded that the patient was reasonably fit - for a 150-year-old.Two engineers from GEI Consultants Inc., based in Winchester, MA, conducted the safety
inspection as part of a State-mandated program to have more than 1,000 dams in Massachusetts reviewed before the end of this year.
Engineers Anastasia Papadopoulos (top) and Lee Wooten inspect the dam November 10. The winter drawdown was suspended for a couple of hours to allow a closer look at the sluiceway. When the dam was last inspected, in 2001, the work was done by State engineers. Under the new program, dam owners are required to hire - and pay for - private companies to do the work. The Foster's Pond Corporation selected GEI - a nationally known geotechnical engineering firm with 15 offices nationwide - from among four pre-qualified companies that responded to a Request for Proposals.
GEI Vice President Lee Wooten and Senior Project Manager Anastasia Papadopoulos met with three representatives of the FPC during the inspection: FPC president Steve Cotton; Treasurer Dave Brown, who drew the plan for the new access-way by the dam; and Willard Circle resident Scott Fumicello, a skilled mason who has generously volunteered his time and equipment to construct the access-way and undertake significant maintenance work on the dam.
GEI's formal inspection report must be filed with the State by December 15, and will include written recommendations for patching up some parts of the dam which have suffered from neglect over the years. But Wooten indicated that he had found no major defects requiring expensive repairs.
Wooten outlined to the FPC representatives his recommendations for fixing damage to the crest of the dam caused by last May's flooding. He recommended clearing additional trees from the crest, since their roots can provide channels for water to leak through the dam. He also recommended clearing brush and soil from an auxiliary spillway - a gully about 75 feet east of the dam which empties onto Rattlesnake Hill Road at the new access-way - which appears to have been designed to relieve pressure on the dam in the event of extreme flooding conditions.
Winter Drawdown Starts
November 2006
The 2006-7 winter drawdown got underway November 1, as the first "stop log" was removed from the Foster's Pond Dam. By the end of the month, when the drawdown process is complete, the water level in the Pond will drop about 16" below the bottom of the spillway - the main waterfall over the 150-year-old structure.Depending on how much rain falls, the water level will drop less than an inch a day as the drawdown proceeds. The only means of affecting the pace is the primitive control - three
boards nested in the narrow sluiceway next to the spillway - that was restored last year after decades of neglect. As each of the three boards is removed, the Pond level drops a little more. The concrete-lined bottom of the sluiceway is a foot and a half below the level of the spillway, setting the limit on how far the Pond can be lowered.
The '06-07 winter drawdown began November 1. The removal of the first of three stop logs allowed water to start escaping through the narrow sluiceway to the right of the spillway. The main reason for lowering the Pond is to protect the dam. The drawdown creates reserve capacity for the winter's snow and ice, so that the spring melt is less likely to overwhelm the dam. That can result in "overtopping," a potentially dangerous condition for an earthen dam.
Last year's drawdown - the first in more than 30 years - worked perfectly, with no adverse effect on shallow wells and a perfectly-timed refill with no overtopping. But Mother Nature had a surprise waiting: shortly after the refill, torrential rains flooded much of the Northeast, and the Foster's Pond Dam overtopped. The Corporation is still in the process of repairing the scouring caused by the dramatic flooding conditions.
The drawdown also is aimed at killing shoreside aquatic weeds, which are vulnerable to freezing. And shoreline landowners have a chance, while the water is lower, to clean weeds and other debris, as well as repair docks.
The Corporation is authorized to undertake an annual winter drawdown under an Order of Conditions granted by the Andover Conservation Commission and upheld by the State Department of Environmental Protection. The five-year Order, which also allows herbicidal weed treatment of Foster's Pond, expires in January, 2010.
Thirteen owners of shallow wells near the Pond were notified of the impending drawdown in mid-October. Even though none of the wells lost water during last winter's drawdown, the notices are required by the Order of Conditions.
The Pond will be refilled next Spring, beginning in April.
Dam Spruces Up For Inspection
October 2006
The Foster's Pond Dam, primping for its first date in five years with with a civil engineer, got the groundskeeping equivalent of a shave and a haircut October 25.A two-man crew from Andover-based Forever Green Lawn & Landscape, hired by the Corporation to clear brush from the crest and foot of the dam, wielded weed-whackers and chainsaws for three hours, leaving the dam shorn of a tangle of weeds, ferns and poison ivy that had obscured the structure.
The dam was shorn of its bushy overgrowth in preparation for its first inspection in 5 years. The dam is due to be inspected in the next couple of weeks under new State requirements which compel private dam-owners to hire engineers to undertake safety checks. The Foster's Pond Corporation has retained GEI Consultants, Inc., headquartered in Winchester, MA, to conduct the state-mandated inspection of our dam.
The dam was last inspected in 2001. At that time, State employees did the inspection, at no cost to the dam-owner.
The brush-clearing also cleaned up some of the remaining scrub in the new "pocket park" the Corporation has created next to the 150-year-old dam. Further work will be done this Fall to finish off the neighborhood-friendly accessway to the shore of the Pond and repair damage caused by last May's flooding.
Corporation Receives Grant
October 2006
The Foster's Pond Corporation has been awarded a $7,500 grant from the Boston Foundation to help with the costs of a state-mandated safety inspection of the dam.The grant was made from the Bessie P. Goldsmith Fund, Bessie's bequest to preserve her beloved woodlands on the eastern shore of Foster's Pond. The Boston Foundation, as trustee of Bessie's estate, is the largest landowner on the Pond.
Under new State laws and regulations on dam safety, the FPC - along with 1,069 other dam-owners in the State - has been ordered by the State's Office of Dam Safety to hire a professional engineer and conduct an inspection of the dam. The Corporation issued a Request for Proposals last month to four prequalified engineering firms, and all four have submitted proposals to perform the inspection. The Corporation's Board of Directors will make a selection on October 11. The inspection is required to be completed by December 15.
New Pathway Takes Shape
September 2006
For the first time in living memory, you can stroll to the crest of the Foster's Pond Dam over a gently sloping path.The Corporation's plan to improve the little "pocket park" next to the 150-year-
old dam is beginning to take shape. The new access to the shoreline is still a work in progress, but the area is already a more appealing spot, with tangled bushes and decaying fences replaced by a mat of wood chips and a new vista of the Pond.
There's a new pathway to the top of the Foster's Pond Dam. As of September 20, the chips were down and a new "pocket park" was beginning to take shape. On a more functional note, the new path will allow mechanized equipment to get to the crest of the dam, vastly easing the job of maintaining the earth-and-masonry structure. And, in an emergency, equipment can now be brought in to avert a breach.
Most of the work so far has been undertaken by Willard Circles resident Scott Fumicello, an accomplished mason and landscaper who has generously donated hours of labor, and the use of his equipment, to preserve and improve the dam. Rattlesnake Hill Road resident Paul Ross, who chairs the Corporation's Dam Committee, has also played a crucial role in conceiving and executing the project.
It's all part of a plan, developed by the FPC and approved by the Andover Conservation Commission, that includes repairs to the damage from last May's flood. When the work is complete, large boulders will prevent parking at the base of the dam - and discourage boat-owners from scraping their craft along the clay crest, scouring small valleys that can erode in flood conditions.
A heavy chain, mounted on posts, will prevent unauthorized vehicles from entering the new access way. But neighbors - and anyone else parking elsewhere, away from the dam - will have easy access to the shore.
Meanwhile, the dam itself will be subjected to a higher level of scrutiny this Fall as a result of new State laws and regulations on dam safety. Under the new rules, the FPC - along with 1,069 other dam-owners in the State - has been ordered by the State's Office of Dam Safety to hire a professional engineer and conduct an inspection of the dam. The Corporation has issued a Request for Proposals to four qualified engineering firms, and will award a contract to get the inspection done by the December 15 deadline.
Conservation Commission Okays Dam Access Plan
August 2006
The Andover Conservation Commission has given the green light to a plan for a new six-foot-wide path to the crest of the Foster's Pond Dam.The plan, which was submitted by the Foster's Pond Corporation in June, was unanimously approved by the Conservation Commission at a meeting on August 1.
Under the plan, a line of large boulders will be positioned along Rattlesnake Hill
Road, blocking vehicles from parking at the base of the dam. A new access-way will be created about 60 feet northeast of the dam, where a 10' by 20' staging area will be opened up. From there, a six-foot-wide path will lead to the top of the dam. The staging area and the path will be covered with wood chips. A chain will prevent unauthorized vehicles from parking in the staging area or using the path.
Site plan for the new pathway at the dam (as revised 12/06). Click the image for a larger view. The new layout will, for the first time, allow equipment to carry materials routinely to the crest of the earthen dam. In past years, volunteers have frequently had to rely on bucket brigades to lug clay and stone to the dam, and to spread the materials around.
The plan got its start in May, after Dam Committee Chairman Paul Ross surveyed the damage caused by a foot of torrential rains. He suggested an access-way to allow equipment to ferry materials needed for that and future repair jobs. The new path will also allow materials to be safely dumped onto the dam if another flood threatens to breach the 150-year-old structure. Until now, that has been impossible, since equipment would have to fight raging waters to approach the dam from the downstream face instead of from the side.
The plan was drawn up by Dave Brown, in consultation with Scott Fumicello, and approved by the FPC Board of Directors. FPC President Steve Cotton and Brown addressed questions about the plan at the August 1 Conservation Commission meeting.
The Corporation hopes to complete work on the plan this year, in advance of the fall hurricane season.
Clean-Up Crew Tames Overgrowth on Dam
July 2006
The Foster's Pond Dam received its most intensive beauty treatment in more than two years, as volunteers spent the first few hours of their holiday week-endclearing brush, pulling weeds and picking up litter around the historic structure.
Marty Rabinowitz plucks debris from the stilling basin. Buoyed by sunny skies and a balmy breeze, 10 area residents wielded chain saws, lopping shears and pruners to tame the tangle of bushes and vines on the crest of the earthen dam and in its stilling basin at the foot of the picturesque waterfall. They also removed a decrepit,
decades old snow fence, easing access to the Pond from Rattlesnake Hill Road.
Eric Lynn stacks brush for the next load. The dam and stretches of shoreline on either side of it are owned by the Foster's Pond Corporation. Clearing woody growth from the dam, in addition to making the area more attractive, is a safety measure. The roots from woody plants can give rise to leaks in an earthen dam, through an effect known as "tubing."
Dot Tyler pulls weeds from the crest of the dam. Sprucing up the dam was part of a larger effort sponsored by the Corporation, a Pond-wide clean-up. Volunteers managed to pull a half-sunken paddleboat, a tire, a ramshackle raft, and assorted litter from the Pond.
The combined effort more than filled a trailer parked by the dam to handle the haul, leaving a bit more work for a later day.
(L. to r.) David Brown, Stephan Amesoeder, Trish Fleming and David Cardin survey a morning's work. The next major step for maintaining the dam will be repair of erosion caused by May's flooding.
The Corporation has mapped plans to construct a narrow access-way to the crest of the dam, allowing equipment to bring materials to an area near the spillway which was severely eroded when water overtopped the dam in May, washing away some of the clay which caps the structure.
Rain, Rain, Flow Away
June 2006
Even before June was over, meteorologists were declaring May and June, 2006, the rainiest consecutive two months locally since records have been kept. But after taking a beating in May, the Foster's Pond Dam suffered no additional damage in June.As Mother Nature dumped more than 7.5 inches of rain on Andover in the first 10 days of June, volunteers carefully tended the flow over the dam, determined to prevent a repeat of May's overtopping.
The June rains came with enough warning from forecasters that there was time to pull stop-logs from the narrow sluiceway in the 150-year-old dam, increasing the flow and maintaining a manageable water level in the Pond. Water churned into the normally placid stilling basin at the foot of the dam, creating large balls of foam. But the flow remained safely within the concrete-line confines of the sluiceway and the adjacent spillway, the dam's picturesque waterfall. The sluiceway, which had not been used for decades, was restored last year to enable annual winter drawdowns - and to prevent overtopping in periods of heavy rain.
June 10: Water flows over the spillway (left) and churns through the narrower sluiceway, from which two of three "stop logs" have been removed. Both stop logs were reinserted the following day, as rains finally ended. When the rains finally gave way to sunshine on June 11, the stop-logs were reinserted in the sluiceway, diverting the entire flow back to the spillway. And when another round of downpours deluged the region later in the month (forcing postponement of a Pond-wide clean-up event on June 24), a stop-log was removed once again. There was no overtopping during the June rains - and no further erosion of the clay-capped dam.
The Corporation is currently working on plans to restore the eroded spots on the crest of the dam which were created in May's flooding.
Flood of '06 Leaves Its Mark on Foster's Pond Dam
May 2006
Just when it seemed that a successful winter drawdown had spared the dam from any danger of a spring overtopping, torrential rains hit southern New England, rapidly filling Foster's Pond to the highest level many residents could remember and overwhelming the 150-year-old dam's shallow spillway.Roiling waters flowed over the dam's earthen crest on both sides of the concrete-
lined spillway, scouring a pit the diameter of a kitchen table in one section of the clay cap. The stilling basin - where the dam's picturesque waterfall gently spatters under normal conditions - became a churning cauldron of frothing whirlpools, filling nearly to their top the two 36" culverts which pass under Rattlesnake Hill Road.
Water roils over the dam at 7:45 p.m Sunday, May 14. For a dramatic 1-minute video by Foster's Pond Road resident Kemper Mazzarelli, click on the image above. The storms had come on too fast to permit lowering of the Pond in advance. Some of the pressure on the dam might have been alleviated by removal of the stop logs in the narrow sluiceway - the crude mechanism which had allowed this year's winter drawdown. But the water level came up so rapidly that it soon was too late to reach the stop logs, which are difficult to pull out even in calm conditions. With water
flowing over the concrete abutments on both sides of the sluiceway, the task became impossible.
May 16: Overtopping continues at the west end of the dam (on right). Under normal conditions, the only flow should be over the concrete spillway (the waterfall on the left). The peak appeared to come on Sunday evening, May 14, when Foster's Pond Road resident Kemper Mazzarelli grabbed his video camera and recorded the maelstrom at the dam. (To download, click here.)
Once the water began to subside - revealing some of the damage to the dam - others came to the rescue. Dam Committee Chairman Paul Ross, joined by Glenwood Road residents Dave Brown and Trish Fleming, managed to lay down a waterproof membrane over the worst area of
erosion, securing it with large rocks and protecting the spot from further scouring.
May 16: The normally placid stilling basin remained a seething cauldron, nearly filling the culverts under Rattlesnake Hill Road. But still the waters came. By May 16, the water level had fallen several inches, reducing the overtopping on the east side of the dam to a trickle. Meanwhile, the west side of the dam, where the sluiceway is located, continued to experience overtopping, and the stilling basin continued to roil.
May 16: On the east side of the dam, a makeshift covering protects the clay cap from further erosion. The dam never appeared in danger of giving way, but serious overtopping is never a good thing for an earthen dam. The FPC owns the dam, and officials in the organization have already begun mapping out plans for repairs - and considering improvements which will allow equipment to get onto the dam in an emergency.
Although the dam suffered some damage, things could have been worse. A lot of maintenance paid off. Two good-sized trees were washed over the dam, but prior clearing of trees and brush from the dam's crest meant that the water-borne debris did no harm going over the top. Such debris crashing into trees on top of an earthen dam can uproot them, leaving large holes and the potential for a disaster.And diligent clearing of brush from the stilling basin left the culverts clear to handle the massive flows.
Winter Drawdown? Consider It Water Over the Dam
April 2006
The winter drawdown came to an end on April 25, as water began trickling over the spillway of the Foster's Pond Dam for the first time since last November.Despite six weeks of unusually dry weather, the Pond refilled on schedule. The process started on March 14, when the first "stop log" was replaced in the narrow sluiceway which regulates the water level. The Pond then began rising at the rate
of about 1/2 inch a day. By April 24, the level had risen the full 16" of the peak winter drawdown, and water was lapping at the edge of the 12-foot wide spillway which channels the dam's picturesque waterfall. The following day, the third (and last) stop log went in, completing the drawdown cycle by shifting the entire outflow of the Pond to the spillway.
Water flows over the spillway for the first time since November, 2005, marking the end of the 1st winter drawdown in more than 30 years. The main purpose of the drawdown was to prevent overtopping of the dam - a potentially dangerous event that can occur when spring rains and snowmelt add so much water to the Pond that the outflow overwhelms the spillway and surges over the earthen crest of the dam. And while Mother Nature served up little snow over the winter, the drawdown proved to be a reassuring exercise.
Three "stop logs" block flow through the sluiceway, which was restored to operation last fall after decades of neglect. The stop logs will stay put until next November - unless heavy rains require the release of water to prevent overtopping the dam. The process worked flawlessly. No shallow well owner reported losing water. The water level fell in the Fall and rose in the Spring on the schedule recommended by experts. And the drawdown permitted the Corporation to undertake minor maintenance on the dam in places that are usually submerged. Still to be determined: Whether the drawdown had the often-observed effect of killing submerged shoreline weeds that were exposed to frost.
The Corporation is authorized to undertake an annual winter drawdown under an Order of Conditions granted by the Andover Conservation Commission, and upheld by the State Department of Environmental Protection, last year. The five-year Order, which also allows herbicidal weed treatment of Foster's Pond, expires in January, 2010.
Temperatures, and Pond, Get Set to Rise
March 2006
As Spring nears, the Winter drawdown of Foster's Pond has been put in reverse. On March 14, Dam Committee Chairman Paul Ross re-inserted one of the three "stop logs" used to control the water level of the Pond, beginning the process of slowly raising the water level.
The stop-logs - 12" wide boards that span the narrow sluiceway in the Foster's Pond dam - were removed last November to lower the water level for the Winter. The drawdown allowed the Pond to absorb some heavy snows, and extraordinary inflows that were observed this Winter coming from Frye's Brook, without overtopping the earthen dam. Freezing conditions are also expected to have killed some of the aquatic weeds whose root systems were exposed.
State guidelines call for pond drawdowns to be reversed beginning in March, with the aim of refilling the water bodies by early to mid-April. The guidelines also call for some downstream flow to be maintained throughout the refill process, so expect to see some water coming over (or between) the stop logs as each is replaced, one by one. Much more water is rushing into the Pond from Frye's Brook, so the Pond will rise.
No sooner did the first stop log go in than the Corporation got some unsought assistance in stopping the flow. Beavers have been seeking to plug the sluiceway with branches, which have to be removed almost daily.
Pond Drops to Target Water Level (Almost)
December, 2005
The first Winter drawdown of Foster's Pond in more than 30 years lowered the water level about 16 inches, just shy of the 18-inch drop targeted by the Corporation.
The 16-inch decline was measured during the final week of November, just before heavy rains briefly raised the water level. By December 3, the pond had receded once again to about 14 inches below the bottom of the spillway of the Foster's Pond dam. While the level will continue to fluctuate -as it does throughout the year - it appears that the drawdown will stabilize at around the 16-inch mark.
The achievement was a welcome sight to Dam Committee Chairman Paul Ross, who has rallied volunteers to maintain the 150-year-old dam and keep the area clean. The drawdown is primarily a safety measure, designed to allow Spring rains and snow melt to fill the Pond without overtopping - and eroding - the earthen dam.
The extent of the drawdown is limited by the size and depth of the dam's sluiceway - the narrow channel next to the much wider spillway over which the dam's picturesque waterfall flows for most of the year. Flow through the two-foot wide sluiceway is regulated by removable "stop logs." The stop logs have all been taken out, and as the Pond level has fallen, the outflow has tapered off as the volume approaches that of the inflow from Frye's Brook.
In the 1930's, the Pond was lowered by several feet after an 8-inch iron pipe, with a valve, was installed. But that mechanism rusted out more than 30 years ago and is now embalmed in concrete. The 16-inch drawdown achieved this year is apparently about the maximum that can be attained without a major reconstruction of the dam. An Order of Conditions issued by the Andover Conservation Commission and later approved by the State's Department of Environmental Protection had set 18 inches as the outside limit on the drawdown.
Drawdown: 12" and Counting
November, 2005
Two weeks into the drawdown of Foster's Pond, the water level had fallen one foot, two-thirds of the way towards the target set by the Corporation.
As of November 14, the Pond was 12 inches below the bottom of the spillway of the Foster's Pond dam, with water continuing to flow steadily out of the two-foot wide sluiceway that can be used to regulate the level of the Pond. When the level drops to 18 inches below the bottom of the spillway, a wooden stop-log will be re-inserted in the sluiceway to maintain the lower water level for the remainder of the winter.
The drawdown began November 1, with the water level dropping - as planned - by about an inch a day.
Winter Drawdown Slowly Lowers Pond
November 2005
For the first time in more than thirty years, the water level of Foster's Pond is being drawn down for the winter.
Under the watchful eye of the Corporation's Dam Committee, the sluiceway ofthe Foster's Pond Dam has been opened, lowering the Pond by about an inch a day. When the water level is 18 inches below the bottom of the dam's spillway, boards will be replaced in the sluiceway (the narrow channel to the right of the spillway) to maintain the lower level until next Spring.
The drawdown began November 1, in accordance with an Order of Conditions approved by the Andover Conservation Commission and affirmed by the State Department of Environmental Protection earlier this year.
As of November 10, the water level was about 7" below the bottom of the spillway - about the same level it was in September, before torrential rains filled the Pond and sent water rushing over the dam. The aim is to lower the Pond another 11 inches by December 1. The 18-inch drop is the maximum allowed under the Order of Conditions - and pretty near the limit that can be achieved with the existing sluiceway.
The primary reason for the drawdown is safety. At least three times in recent years, melting ice and heavy spring rains "overtopped" the dam - with water overflowing the concrete spillway and cascading over the earthen embankments on either side. Overtopping, which can quickly erode an earthen dam, is one of the principle causes of the catastrophic failure of such dams.
The drawdown has other purposes, too. The drawdown will allow the Dam Committee to undertake additional maintenance on portions of the dam which are normally under water. Drawdowns are also considered effective in controlling some aquatic weeds, which die from the combined effects of freezing and drying.
Keeping a steady flow through the sluiceway has proved a bit harder than expected. Almost every night since the sluiceway has been open, resident beavers have attempted to plug the channel with freshly gnawed branches.Volunteers have cleared the debris, throwing it on a steadily growing heap between the dam and Rattlesnake Hill Road. The Dam Committee will remove the brush pile as part of its maintenance activities later this year.
The Pond will be allowed to refill next April.
Shallow Well Owners Get Drawdown Notification
October 2005
The Corporation has sent notices to shallow well owners, reminding them that the Pond will be drawn down 18" beginning on November 1.
The notices were sent to 13 property owners in occupied houses near the Pond which may use shallow wells for some or all of their potable water. The properties were identified in a survey conducted by the Corporation last year. The advance notice is required in the State-approved Order of Conditions authorizing annual winter drawdowns of the Pond.
Winter drawdowns were a frequent occurrence on Foster's Pond until about thirty years ago. In the 1940's, according to one older resident, the Pond was drawn down by about six feet, allowing the use of vehicles to remove tree stumps from areas in the main Pond. Even with these larger drawdowns, shallow wells in the area did not lose water.
Two different methods were used for earlier drawdowns. The original mechanism was the simplest: the removal of "stop logs" from the three-foot wide sluiceway adjacent to the spillway over which water normally flows. At some point in the latter half of the last century - the records are not clear when - an 8" iron drainage pipe was inserted at the bottom of the sluiceway, with a valve operated with a large metal wheel. That mechanism had rusted shut by the early 1970's, and this Fall the remnants were encased in concrete.
Today's drawdown mechanism is the old-fashioned one. Stop logs will be removed to allow a gradual drawdown. They will be left out for the winter, then restored next Spring to allow the Pond to refill.
The November 1 commencement date of the drawdown follows the State-recommended schedule for pond drawdowns, allowing wildlife to move to deeper water, locate alternate lodge sites, or relocate their food caches prior to freezing conditions. The drawdown will be gradual, spread over a month-long period.
Prior to several inches of early October rains, the Pond level had fallen to about 7 to 8 inches below the bottom of the spillway, which had not had water flowing over it for several weeks. October's downpours raised the water level by 5 or 6 inches.
The drawdown is aimed at increasing the winter storage capacity of the Pond, so that Spring rains, combined with melting snow and ice, will not overtop the dam - sending water over the sides and damaging the clay top. Overtopping of an earthen dam carries the risk of catastrophic failure.
Sluiceway Restored to Enable Winter Drawdowns
October 2005
Volunteers mixed and poured nearly a ton of concrete - by hand - as Fall maintenance of the dam cranked into high gear.
Dam Committee Chairman Paul Ross, John Lugus, Dave York, and Steve Cotton hauled 80-pound sacks of concrete mix to the sluiceway, where it was used to resurface the sides and plug holes in preparation for this winter's drawdown of the Pond. The sluiceway - the two-foot wide opening to the right of the spillway - will be opened November 1 to begin the drawdown.
John Lugus and Paul Ross prepare for a pour
The four men labored for five hours October 1. Paul, John and Steve returned for another couple of hours October 3 to finish the work in the sluiceway and patcha nearby sinkhole on top of the dam. They also poured a layer of concrete over the crumbling mechanism that had once opened the valve in an 8-inch pipe used in past years to lower the Pond. The pipe has long since collapsed, and the valve hasn't worked for decades.
Paul finishes the surface
By the time they were through, the volunteers had carted 1930 pounds of dry concrete mix to the project.
The work in the sluiceway wound up a critical phase of this year's maintenance - the work that had to be done in dry weather and before the water could be let into the narrow channel. Once the concrete cures and the wooden forms are removed, the next step will be to take out the temporary sand-bag dam that has kept the sluiceway dry.
Still to come: a bucket brigade to spread clay along Pond-facing slope of the dam. After frost has subdued the poison ivy which covers much of the dam, volunteers will also be needed to remove brush from the top and front of the 150-year old structure.
Fall Dam Maintenance Under Way
September 2005
In preparation for the first winter drawdown in more than three decades, the Dam Committee has undertaken a program of cleaning and patching parts of the dam - while keeping a wary eye out for the 6-foot black snake that seems to have made its home nearby.
The work, coordinated by Dam Committee Chairman Paul Ross, began on Labor Day, when Scott Fumicello repaired portions of the sluiceway. On September 17, John Lugus and Steve Cotton joined Paul for several hours of backbreaking work, cleaning the culverts and removing a concrete barrier that prevented drawing down the water level more than a few inches. With the barrier now removed, the Corporation will be able to draw the Pond down a full 18" this winter, as authorized by State and local officials.
Further maintenance work is scheduled before the drawdown, which will begin November 1.
The main purpose of a winter drawdown is to create capacity to accommodate the accumulation of winter snows, so that spring runoffs do not result in flooding which "overtops" the dam. Overtopping - which occurs when the water level is so high that the flow cannot be contained within the concrete spillway, and water rushes over the earthen sides of the dam - can be dangerous, resulting in erosion of the dam and the potential for a catastrophic failure.
The dam has experienced overtopping with increasing frequency in recent years, suffering only minor damage but occasioning major concern on the part of State and local safety officials. To see pictures of the 2004 overtopping, click here.
Annual winter drawdowns of up to 18" were approved as part of an Order of Conditions okayed by the Andover Conservation Commission and affirmed by the State Department of Environmental Protection in March, 2005
Dam Maintenance Proves Its Worth
April, 2005
Weather forecasters were predicting the type of flooding that nearly overwhelmed the dam in 2004, but things looked a lot different when the April rains hit in 2005. Work by the Dam Committee - with special efforts put in by Paul Ross, Rick Keller, and Scott Fumicello, among others - restored the dam's ability to deal with the excess flow. New "stop logs" in the sluiceway (that two-foot wide slot just to the right of the spillway, where water normally comes over the dam) can now be removed to allow the safe release of additional water when the Pond is rising. Quick work by Dam Committee Chairman Paul Ross on the eve of the highest predicted flow prevented overtopping - a condition when water is so high it pours over the earthen cap of the dam on either side of the spillway, eroding the top and presenting a potential safety problem. Closely monitoring the water levels, Paul removed two of the stop logs, permitting the safe escape of water that would otherwise have built up behind the dam. The result: This year, with the release of the excess flow through the sluiceway, the Spring runoff stayed safely within the spillway, and the earthen cap of the dam suffered no erosion.
April Showers Hit Dam Hard
April, 2004
If anyone needed a refresher course on why we've got to work on the dam, Mother Nature came through in April with downpours which sent water surging out of the spillway and over the earthen embankments on both sides, exposing some leaky areas.
Dam Committee Chairman Paul Ross noticed the rising level of the Pond during the first week-end of April, and began planning to lay down sandbags. Instead, he hit on the idea of putting down waterproof landscaping cloth, anchored by concrete blocks - a temporary measure which helped stave off significant erosion of the clay cap on the left side of the spillway.
Foster's Pond Road resident Dave Adilman captured the overtopping in a pair of photos.
Dam Exfoliated: Committee teams up to give dam a clean appearance
November, 2003
Members of the Corporation's Dam Committee braved poison ivy and ice-cold water to tame brush, clear the spillway, and remove obstructions from the downstream culverts of the Foster's Pond Dam. They also brought down a dead tree that was standing on the top of the dam - a hazard whose removal had been sought by the State's Office of Dam Safety.
The work on November 22 left the dam free of woody growth which experts say can endanger the integrity of earthen dams. One birch tree near the edge of the dam was left standing; the Committee plans to return in the winter, when the tree can be dropped onto the ice for easier removal.
Removal of the plant cover allowed the Committee to take a closer look at the condition of the dam, revealing the need for work on the sluiceway as well as other parts of the 150-year-old structure. Committee Chairman Paul Ross plans to draw up a list of items that must be addressed, as well as a timetable for dealing with them overthe next several months.
The Committee will also be exploring low-cost means for drawing down water in the Pond during winter periods. Winter draw-downs are a common means of addressing three issues: dam maintenance; avoidance of "overtopping" during spring melts; and weed control. A draw-down would require Town approval, and would not be undertaken unless approved by FPC members, after review by both the Dam Committee and the Weed Committee. No draw-down is under consideration for the 2003-2004 winter.
