Truesdale Lake  

South Salem, New York

October 19 Lake Drawdown Article in Record Review Newspaper

I write a bi-weekly column in the Record-Review ( called “Talk of The Town” about current events in Lewisboro. Occasionally I will also write an article and submit photos about various topics and events in town.

A few weeks ago (Oct 19 edition) I wrote about the Truesdale Lake drawdown.

I encourage anyone who is interested in local news to subscribe to this paper which publishes every Friday and is only available in print form. The more Lewisboro subscribers the more they cover in town. The Record Review is the Newspaper of Record” for the Town of Lewisboro. This means they publish all of the town’s meeting and legal notices as required by NY State law. And they cover Town Board meetings, Planning Board Meetings, Zoning Board meetings, and School Board meetings.

I have attached the drawdown article – and the top half of my Talk of The Town article – to this post (see below). A bunch has happened since then with the drawdown – check the Nextdoor Truesdale site for updates and comments.


Full text of the article:

Truesdale Lake Drawdown Article  

By Robert J. Cummings

In the upcoming weeks, Truesdale Lake residents will be lowering the level of the lake approximately two to three feet for the winter season. The practice is called a drawdown and is common on lakes with dams. In fact, drawdown was an annual occurrence at Truesdale Lake until the secondary spillway in the Truesdale dam – which was three feet below the waterline – rusted closed in the 1960s and was not fixed at the time. The lake management company Pond & Lake Connection has a time-proven solution to this: siphoning the water over the spillway.

Why draw the water down? According to James Gorman at Pond & Lake Connection “The purpose of the drawdown is to expose lake weeds to freezing and drying over the winter, preventing or slowing their growth in the summer. In addition, the drawdown dewaters the exposed sediment and organic matter, compacting the exposed soil.” This makes it more difficult for weeds to attach to the bottom and grow in the shallow areas. James continued, “The hope is that the decrease in plant growth in the lake caused by the drawdown will reduce the need for summer herbicide treatment that is currently used to keep the weed growth at a manageable level.”  

A secondary benefit of the drawdown is that it will allow shoreline homeowners access to repair seawalls and docks. In addition work can also be done raking exposed dead vegetation much like fall leaf cleanup. Depending on the scope of the work, building and wetlands permits may be required from the Town of Lewisboro, the New York State Department of Environmental Conservation (DEC), or both.

Some of the plant species most commonly targeted by drawdown that are present in Truesdale Lake include Eurasian watermilfoil and Brazilian elodea. A plant species in Truesdale that is not as easily affected by drawdown is curlyleaf pondweed because the seed pods, called turions, are present in both shallow and deeper areas of the lake. Curlyleaf pondweed is an invasive species and notoriously difficult to control.

The plan, according to Lake Management Committee member Lara Gorton, was to have the siphon and pipes in place on October 15. However, the unusually heavy rainfall in September – including the remnants of two hurricanes – kept the lake level higher than normal. This pushed back the installation by a week or more.

Pond & Lake Connection, based in nearby Brookfield, CT, plans to install the pipes and pumps next week. This will include three pipes and siphons, which will go over the Truesdale dam spillway at the north end of the lake. Once the siphon is started – usually  via a small pump hooked up temporarily, the water will continue to flow naturally through the pipes using gravity. The pipes are 6-inch diameter PVC pipes and the siphons will be in the lake at different heights. One siphon will be at 3 feet below the regular water level, one siphon will be at 6 feet below the regular water level, and the third pipe will be a backup with a height in between. The first pipe and the second pipe will be used to draw down the lake to the desired level. After the drawdown level is achieved, the first pipe will be shut off while the second pipe will be used to keep the water flowing as needed throughout the winter to maintain the drawdown level. This is for two reasons. First, more water is always flowing into the lake all the time from rain, snow, and snow melt during the winter. Second, the DEC requires the siphon to have a flow as long as the water is not frozen. The actual drawdown will take place in the six weeks between mid-October and early December. By the time the drawdown is complete, the lake will be around two to three feet lower than its usual winter height.

Once the drawdown is in place, the lake will be kept at that height until February 1, 2019. This will provide time for the lake bottom to compress, and also for the cold winter weather to freeze exposed weeds. At the beginning of February, the valves will be shut off and the lake will begin to refill naturally. Given historical records and inflow studies previously done, the lake should be back to its usual height by about May 1 and likely well before then. The exact timing of the drawdown and the plans will of course be heavily weather influenced. 

Lara noted the siphon and pipe installation “will be monitored weekly by Pond & Lake Connection. James Gorman, who is our contact, has been very helpful and accessible since we contracted with them for lake treatment and management in 2016.” One item Lara said was of concern was if the siphons would draw aquatic animals such as turtles and fish through them “James has addressed this in the past with a wire barrier over the input siphon that would prevent wildlife from being sucked downstream.”

Some of the questions residents have had about the drawdown include what to do with their docks over the winter as the lake level decreases. Most of the docks are attached at the shoreline and are floating docks, as the Truesdale Dock Committee requires. These docks will simply settle to the exposed bottom of the lake close to the shore as the water level lowers and the ends will remain floating on the lowered lake or possibly on the lake bottom, depending on the slope of the shoreline. The committee recommended that the larger floating “party docks” be anchored for the winter in deeper water. Some residents have already started doing this in preparation for the drawdown.

Other questions related to repair work on seawalls. Residents wanted to know what repairs they could do without needing a permit. Since this is always different from property to property, the committee has advised checking the town code and talking with the building department and the town wetlands consultant before starting any work. The state DEC can issue hefty fines for violations — and consulting with the town beforehand can avoid this.

If this year’s drawdown is successful, the plan is to make it an annual occurrence again at Truesdale Lake, study the impact it has on weed growth, and even explore potential permits to dredge selected areas of the lake in the future. For now, Truesdale residents are excited to see what happens this year.

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