Overview: What the Hydro-Rake Does
2018: Hydro-Raking Starts
2017: Hydro-Raking
2016: No Hydro-Raking
2015 Hydro-Raking
2014 Hydro-Raking
2013 Hydro-Raking
2010: No Hydro-Raking
2009 Hydro-Raking
2008: No Hydro-Raking
2007 Program
2006 Program
2005 Program
2004 Program

What the Hydro-Rake Does

The hydro-rake removes nuisance aquatic vegetation and debris (leaf material and decaying matter) from individual beach-front areas. The Hydro-Rake is basically a back-hoe with a rake attachment, mounted on a paddle boat. The Hydro-Rakemachine removes the roots and stems of nuisance aquatic vegetation up to a depth of 12 feet and can "clean" an average beach area 75 ft by 50 ft in approximately 1 to 2 hours, depending on the weed densities, depth and bottom characteristics. Removal of leaf litter, organic debris, or dense vegetation may require considerably more time.

The hydro-rake has no on-board storage. Each rake load must be deposited on the shore at the water's edge, from where the property owner is responsible for hauling or trucking the material to a permanent, upland disposal site. The stuff can be used in your garden.

Hydro-raking is performed in accordance with an Order of Conditions issued by the Conservation Commission. On Foster's Pond, individual property owners do not need to apply for a permit in order to participate in the group program, but their sign-up forms MUST be included in a package of materials submitted for formal approval prior to the commencement of each year's hydro-raking.

We have used one contractor, Solitude Lake Management (formerly named Aquatic Control Technology), since we began hydro-raking in 1992.

If you have questions about hydro-raking, please e-mail Steve Cotton.

2018: Hydro-Raking Gets Underway

Under cloudless skies, hydro-raking began on April 24 and was expected to take about a week.


April 24: (Above) The hydro-rake goes to work in the Main Pond. Photo by Jim Cyrier. (Below) Operator Matt Lafrennie heads to shore with a load of leaves and twigs.


Thirteen shoreline property owners signed up for hydro-raking, the largest number since 2004. Nine properties in the Main Pond and four in the Outlet Cove are on a list of hydro-raking participants formally approved by the Andover Conservation Commission on April 17.

2017: Spring Hydro-Raking

After a drought left the Pond too low to accommodate the hydro-rake in the Fall of 2016, a new schedule was developed for 2017.


April 24: The machine employed in 2017 was smaller, faster, and more maneuverable. It had a narrower rake with the tines closer together, retaining more muck than the rake used in previous years.

Seven shoreline property owners - six on the Main Pond, one in the Outlet Cove - signed up for hydro-raking in April. In all, 18 hours of raking were performed, with the hydro-rake beginning its work April 24 and finishing on April 26.

After a series of spring rainfalls - and even a mid-April flood warning - the Pond was at its highest water mark in several years, making for easy access into shallow coves.

2016: No Hydro-Raking

As a record-breaking drought reduced the mid-Summer water level to the lowest in memory, hydro-raking became a non-starter.

The rake must deposit spoils on the shore, above the high water mark, and with each passing day of dry weather, that shoreline got farther away from open water, beyond the rake's limited reach.

In consultation with the Corporation's lake management consultant, a plan was formulated to consider hydro-raking in the spring of 2017, as soon as the water level is restored.

2015 Hydro-Raking

After a mid-summer herbicide treatment sharply reduced weeds throughout the Pond, only six shoreline property owners signed up for hydro-raking.

All six of the shorefronts are located on the Main Pond. A total of 16.5 hours of raking were requested, barely above the minimum needed to bring the hydro-rake to the Pond.

Near-drought conditions over the summer slowed the work. With the Pond at lower-than-normal levels, the hydro-rake could not reach as far inland as usual to deposit spoils. In order to complete the requested work at some sites, the operator let the spoils piles settle overnight to form a more stable base, then resumed work the following day.

The Andover Conservation Commission gave its approval to the 2015 program on October 6. Raking began October 14 and finished on October 16.

2014 Hydro-Raking

Hydro-raking got underway on October 8, on a perfect New England fall day. The work concluded a week later, with the balmy weather continuing to hold.

Ten shoreline property owners had signed up for hydro-raking by the August 20 deadline. Six of the properties are located on the Main Pond, while the remaining four are on the Channel. In all, 25.5 hours of operating time were requested.


October 15: The hydro-rake, after clearing weeds at the dam, brings in the trunk of a birch tree that had been felled by beavers.

In addition, the Corporation commissioned an hour of raking at the dam to remove vegetation from the site of a small but persistent leak. That set the stage for the next phase of the repair job, bringing clay and crushed stone in to plug the leak. The rake also cleared a birch tree that had been felled recently by a beaver.

The Conservation Commission had unanimously approved the list of 2014 participants at its September 16 meeting. The formal vote was required before the work could commence.

Traditionally, hydro-raking has been scheduled on Foster's Pond in the Fall, to minimize the chances of an algae bloom and avoid interfering with swimming.

2013 Hydro-Raking

For the first time since 2009, the hydro-rake returned to Foster's Pond to remove muck and rooted vegetation along nine shoreline properties. The raking began on October 10 in the Main Pond, where five property owners had signed up for a total of 12 hours of operating time. Another two properties in the Channel and two in the Outlet Cove were raked for a total of eight hours. The work was completed on October 15.

The four-year gap in hydro-raking was largely the product of successful chemical weed treatments. The herbicidal treatments, although aimed at non-native plants, had reduced the growth of lilies, and many hydro-raking participants have used raking to carve a pathway through the lilies along their shorelines. With the temporary disappearance of some lily patches, the demand for hydro-raking fell off. In addition, low Fall water levels occasioned by near-drought conditions had in some years rendered hydro-raking impossible, since the rake must snuggle close to the shoreline to deposit spoils.

In 2013, however, the accumulation of organic debris from falling leaves and decaying weeds, the resilience of the lilies and the return of normal rainfalls all combined to spur renewed interest in hydro-raking.

2010: No Hydro-Raking

Early in 2010, torrential rains left the Foster's Pond Dam in need of repairs. The water level in the Pond had to be lowered to undertake the work, which was completed in June. By then, a drought had settled in, and the water did not return to its normal level for the remainder of the summer. The Pond remained too shallow for the hydro-rake, which must be able to reach the shoreline to deposit each rakeful of muck.

2009 Hydro-Raking

Eight shoreside property owners participated in the 2009 hydro-raking program. Participants included five owners on the Main Pond, one on the Mill Reservoir, and two on the Channel. Collectively, they requested 20 hours of work, which was performed by Aquatic Control Technology. The Andover Conservation Commission approved the 2009 hydro-raking program on October 6. The work began to begin on October 19, and took three days.

2008: No Hydro-Raking

With chemical weed treatments keeping most shorelines free of weeds in 2008, few Pond residents saw much need for hydro-raking. As a result, 2008 was a "bye" year for raking. Those residents who usually request hydro-raking were adopting a wait-and-see approach for 2009.

2007 Hydro-Raking Wraps Up
October 19, 2007

It began with flawless fall weather, and concluded under a cloudburst. The 2007 hydro-raking program spanned three days, and, for the first time ever, included properties bordering the Mill Reservoir.

As the first rays of the morning sun caught swirls of mist rising from the Pond, the hydro-rake chugged away from its Willard Circle launch site to begin three days of shorefront muck-removal.


October 17: The hydro-rake brings up a rakeload of muck in the Main Pond, as mist blankets the surface in the distance.

Ten property owners signed up for the 2007 hydro-raking program. The list of participants was submitted to the Andover Conservation Commission, which must annually vote to okay the program before the rake can start its work.

Historically, the Conservation Commission has been very supportive of weed control efforts in Foster's Pond, and the annual vote to approve the hydro-raking has often taken less than a minute.

The 2007 vote proved no exception. At an evening meeting on October 16, the Commission unanimously endorsed the program. The vote came at about 9:30 p.m. In anticipation of the favorable vote, long-time hydro-rake operator Craig Hadley had launched the craft into the Pond earlier in the day. That meant he was ready to go at sunrise the next morning, and the first rakeload of muck came up at 7 a.m.

This year's participants included five owners on the Main Pond, three on the Channel, and - for the first time since hydro-raking started in 1992 - two on the Mill Reservoir. Together, they received a total of 25.5 hours of raking. Although the list of participants changes from year to year, the level of activity has remained fairly constant for the last three years.

The raking began in the Main Pond on October 17, moved to the Channel the following day, and ended in the Mill Reservoir around 1 p.m. on October 19. Lower-than-normal water levels presented something of a challenge in a couple of locations, making it difficult to maneuver the rake close to shore.

Hydro-Raking Starts (and Ends) Under Sunny Skies
October 13, 2006

The hydro-rake - which began its work in the main Pond October 10 under cloudless skies - was hauled out on October 13 in similarly picture-perfect weather.

Hydro-rake begins working in the main Pond, October 10, 2006

Long-time hydro-rake operator Craig Hadley launched the ungainly craft from Willard Circle into glass-smooth waters around 10 a.m. on October 10. The first rakeful of muck came up shortly before noon.

Nine shorefront property-owners and the Foster's Pond Corporation signed up for a total of 26.5 hours of raking for Fall 2006. The list of properties included five on the main Pond and four in the Channel, plus a small amount of raking around the dam.

The list must be approved by the Conservation Commission each year. The Commission unanimously approved the 2006 list of participants at a meeting on September 19. Annual approval has become a routine matter, and 2006 was no exception.

The hydro-rake began its work in the Main Pond, moving to the Channel on Day 2. The work was finished on October 12, but the rake wasn't hauled from the pond until the following day.

Three Days of the Hydro-Rake:  2005
October 2005

The hydro-rake began its work on shorefront properties in the main Pond on October 11, with three days sufficing to finish this year's scheduled program.

The rake was launched from Willard Circle on Columbus Day.  It took a little more than an hour the following morning for the operator to fuel the craft and put up its rain flaps.  The first load of muck came up from the bottom shortly before 8 a.m.

The rake finished its work in the main Pond in one day.  Work in the channel started early in the morning on Day 2.  The third and final day of raking was to conclude with a sweep of the Foster's Pond Dam.

On September 20, the Andover Conservation Commission unanimously approved this year's hydro-raking program for Foster's Pond.  Ten shorefront owners - plus the Foster's Pond Corporation - signed up for hydro-raking this Fall.

With fanwort gone from their shorelines, most property owners put the hydro-rake on hold this year, but some saw an opportunity to make a bigger-than-ever impact on lilies and muck.

Four owners on the main Pond, and six on the channel, arranged for their properties to be raked this year, for a total of 24.5 hours. In addition the Corporation signed up for a half hour of weed removal near the dam.  Last year, 13 participants had 29 hours of work done.

Although the results of the Sonar treatment have been dramatic, the lilies are going to bounce back next year, according to Marc Bellaud, senior biologist at Aquatic Control Technology.

Shoreline owners who want to get rid of lily roots, leaf litter and muck still need to rely on hydro-raking.  And this year, with lily growth impeded by the Sonar, each hydro-rake scoop contained less lily biomass and more room for muck and roots.

ACT advised scheduling the hydro-raking after October 1, giving the Sonar the maximum amount of time to work to avoid stirring up (and potentially spreading) any live fanwort fragments.

The Conservation Commission must formally vote each year to approve the list of participating sites before the hydro-raking can be scheduled.  No site can be added to the list at a later time.

Fall 2004 Hydro-Raking Completed
October 2004

The hydro-rake finished work on Tuesday, October 12, having spent four days cleaning shorefronts at thirteen sites on the Pond.

The hydro-rake began scooping muck and weeds on Wednesday, October 6, following approval of this year's program by the Town's Conservation Commission at its meeting just the previous evening.

Thirteen property owners signed up for a total of 29 hours of hydro-raking this Fall - 17 hours in the main Pond, and another 12 hours in the channel portion of the Pond.

The hydro-rake cleaned the shores of six properties fronting the main portion of the Pond and another seven properties along the channel.  The hydro-rake also removed a concentration of weeds in front of the sluiceway of the dam, making room for the Dam Committee to undertake repair work that will allow use of the stop logs to lower the level of the Pond.