Truesdale Lake  

South Salem, New York

September 19, 2019
by rob
Comments Off on Has Lake Truesdale Sprung a Leak?

Has Lake Truesdale Sprung a Leak?

That was the question we got through email from a local resident.

Thankfully there is no leak — just the very quick effects of the planned drawdown project that was successfully re-engineered by volunteers and Pond & Lake Connection after meeting up with several points of failure last season in the initial trial.

Scot Evans reports: “Today at noon (drawdown day #8) a total of three feet [of water] have been pulled out of the lake. We are now 2 feet below the spillway height with one foot to go which will occur on Saturday 9/21 if both siphons continue operating.”

Truesdale spillway with two 12″ siphon pipes and one 6″ siphon pipe. No pumping, just gravity drawing the water down over the spillway and dam. (photo by Scot Evans)

The drawdown will last until February 1, 2020 – that’s when we will turn off the maintenance pipe. This is the smaller 6″ pipe which we will use to try to keep the lake level 2.5 – 3 feet below the spillway level.

After then the lake will fill up with winter snowmelt and spring rain. We anticipate it will be back to regular height by May 1, 2020 and likely well before then.

Check for more timely updates and post there if you have questions.

The TEA beach showing the lowered lake level. Currently 2 feet below spillway height and dropping. (photo by Rob Cummings)

September 16, 2019
by rob
Comments Off on Drawdown: Report 1

Drawdown: Report 1

These are some of the email reports and communications from Scot Evans from Truesdale Lake, James Gorman from Pond & Lake Connection, and others involved with the project. Putting selected parts up here for all to see what some of the discussion and learning is looking like.

September 16, 2019

The 6” prototype “helper” siphon shut down today after sucking in air through a whirlpool that developed over its shallow intake tube which is now exposed. No big deal since we are well ahead of schedule during this nice drought we’re having. (See bottom photo.)

View from the west looking east at the spillway with the three siphon pipes installed and water level approximately 1 foot below spillway height.

The siphons have expelled 2.5 feet total and the lake level is now 1.5 feet below the spillway. 

The 12” pipes are still flowing well. The east side pipe has a buckled Fernco fitting near the fill-Tee and the hose clamp has come off of the distal pipe’s lower end as shown in the photo, which I took the day after you energized the siphons. The intense suction has compressed the fitting and the seal is still good. Also, no big deal yet and no need to reposition it or double up on the hose clamps until it shuts down. 

buckled Fernco fitting near the fill-Tee and the hose clamp has come off of the distal pipe’s lower end

When your guys need to climb down, I made steps below the southeast guardrail where it meets the wood beams of the bridge over the siphon intakes. (Where the angled concrete training wall is visible in the second photo above.) I also took a scraper and brush to the spillway’s horizontal deck, so it is clean and not slippery. I marked the painful low hanging bolts under the bridge with ribbon so they don’t prang their heads or shoulders.

So all’s well and no need to do anything yet. I’ll let you know if/when that suction compressed Fernco fitting separates from the tube. 


Good news. Thanks for the updates.
I was thinking for the 6” helper…since we should always have water leaving the lake should I add some pipe to that so when the big guys stop water is leaving?

Something to think about. I can do it later in the month but would be nice to do before the water gets real cold.


September 12, 2019
by rob
Comments Off on Lake Drawdown Has Begun for 2019

Lake Drawdown Has Begun for 2019

The Summer boards have been removed from the dam.

Our lake manager Pond & Lake Connection (P&LC) has installed the siphon tubes that will draw the lake level down another 2-3 feet to expose the lake bed over the winter.

[Read about what drawdown is and why this is being done here.]

As detailed in our drawdown meeting in June, our neighbors Scot Evans, resident math whiz Harold Ossher, and our lake manager liaison Lara Gorton have done an unbelievable amount of work to evaluate the water flow and re-design the siphon design to drawdown the water level this fall. See the detailed schematic below. 

Detail of siphon materials and mechanics

For testing, the original 6″ pipe siphon was reinstalled to use for water flow testing and has been in use over the summer. P&LC has installed two new 12″ pipes to have the drawdown complete by Nov 15.

The drawdown will end Feb 1, 2020 and the lake level will be allowed to rise after then. All dates are approximate as all work is weather (rainfall, snow, drought) dependent. 

IMPORTANT: NO FISHING WITHIN 15 FEET OF THE SPILLWAY WHILE THE SIPHONS ARE ACTIVE! The fishing line and hooks get tangled on the pipes and hardware and create a dangerous rusty hazard for lake volunteers and P&LC workers doing observation and maintenance on the site.

The siphons will be drawing water at 1000 cubic feet per minute. There will be warning signs posted at the dam. 

If all goes as planned, the water level will be 2-3 feet lower than the top of the dam spillway and will expose several feet of lakebed.

With cold weather, frost and freezing, the silt in the exposed shallow areas will compact and weed growth will be minimized. 

We will continue to report on the progress as the siphoning proceeds.

Full cross-section of siphon assembly.
Spreadsheet of water flow analysis for drawdown effort. Inputs are highlighted in blue, estimates are highlighted in red, and outputs are highlighted in green.

July 29, 2019
by rob
Comments Off on Shoreline Maintenance Musings and other Lake Topics

Shoreline Maintenance Musings and other Lake Topics

In conversation and comments from around the lake, the weeds and algae are common topics — especially in the summer. One thing to remember is: We live on a lake, not next to a pool. The lake supports a multitude of animal and plant life. It is all interconnected and interdependent. And we have a large impact on it.

Many of the actions we take directly impact the health of the lake. For example, lawns leading right up to the lake shore encourage geese to land here and nest. Geese that are born and fledged here will return. Geese prefer an unimpeded path from their favorite food: Kentucky Ryegrass (aka lawn) and their water escape route. If you need a perfectly manicured lawn, consider planting a shoreline buffer of wildflowers and tall grasses. This will discourage geese from making your lawn their recreation area. And it will encourage beneficial insects and help native species.

Another area we affect the lake ecosystem is when we treat the lake to cut down on the plant and algae growth. As an extreme example: If we treated the lake to eliminate all plant life, it would kill all of the animals that rely on the plants for food. Then as the water heats up, we would suffer through blooms of toxic blue-green algae. That is definitely on our list of “no thanks.”

In our treatment plan, now managed by The Pond and Lake Connection, we are mainly looking to control the shoreline plants and algae growth that interfere most with the recreational value of the lake. This means we leave the middle of the lake alone since having plants in the water helps the fish, keeps the dissolved oxygen levels high, and can help prevent single celled blue-green algae — which thrive in low-oxygen conditions — from taking over the lake water in the dog days of August.

Our herbicide treatments are usually in the late spring just before Memorial Day weekend in May and once or twice in the early summer as needed. Algae treatments start in late July and can go into August. We are not allowed to treat the lake if dissolved oxygen levels fall to very low levels. This sometimes happens in the late summer and if it occurs, we have to wait for the water to cool down to treat the lake.

We strive for balance, but sometimes nature has other ideas. Plants and algae grow in the lake because that’s what plants do. They have 14 hours of sunlight each day during the summer to fuel them. For the shoreline variety, have to think about them like your lawn. If you don’t mow your lawn it will overgrow and you will not be able to walk through it. The same is true for your “water lawn” – no maintenance and the area around and beyond your dock grows wild. Some people like it that way, others want a clear waterfront. Others simply want a path to swim or boat out from their shoreline. Your needs dictate the extent of the action you personally take.

We have found if you want to control the plant growth around your waterfront or dock, the best and most effective way to control it is hand harvesting or cutting – then removing the plants from the water to dry and then compost. This can be time consuming and labor intensive, but the results typically last 4-6 weeks (sometimes as little as 1 week during peak season). The more you maintain, the easier it becomes over time.

(Note: If you would like more information about tools designed to make harvesting weeds and algae easier, check this page.)

Some other helpful articles from past years:

July 22, 2019
by rob
Comments Off on Lake treatment set for July 23

Lake treatment set for July 23

Pond & Lake Connection will treat the lake for weeds and algae as needed on Tuesday July 23rd. 

We use Clipper for weeds ( and Se-Clear for algae ( There is a 24hr restriction for irrigation with Clipper but no other usage restrictions for either chemical. 

The floating algae clumps in the lake at this time are helping to absorb nutrients and keeping the water column clean. It is called filamentous algae and while alive, green and spongy, they are host to a number of different beneficial organisms for the lake ecosystem.

Here’s a link to read about filamentous algae – 

The algae treatment will kill some of the floating algae. The treated/dead algae will float into the coves, turn black and sticky, and decompose there if there is not enough current to move it downstream. 

Additional chemical treatments will not reduce the volume of algae in the coves – it will actually worsen the situation and create more dead algae accumulation. 

You can collect and remove it from your area or create current to move it downstream to help resolve the accumulation. 

Several riparian homeowners have installed aqua-thruster water circulators along their shorelines to create current and help clear out accumulation. Please contact me if you are interested in more information about installing a circulator or if there are any other conditions in the lake that need special attention.

Thanks – Lara. 

June 27, 2019
by rob
Comments Off on Lake Treatment Set for Today June 27, 2019

Lake Treatment Set for Today June 27, 2019

Pond & Lake Connection in their fan boat. Used for lake surveys and treatment.

Pond & Lake Connection will treat the lake for weeds and algae as needed this Thursday June 27th. 

We use Clipper for weeds ( and Se-Clear for algae (

There is a 24hr restriction for irrigation with Clipper but no other usage restrictions for either chemical. 

If you see a need for extra attention to a certain area of the lake, please let me know and I’ll ask P&L to spot treat in that area. 

-Thanks, Lara

June 5, 2019
by rob
Comments Off on Geese, Goslings, Eggs, and Oil

Geese, Goslings, Eggs, and Oil

A number of residents have been actively oiling goose eggs on the islands of Lake Truesdale since 2008 to control the population of Resident Canada Geese on the lake. But the existing crew of people trained to oil eggs it has shrunk over the years — and we need more people to step up.

If you are interested in helping out, please contact us via email at or via our Contact Form. The process is not too difficult and training is easy. The oiling season for 2019 is over, so it would be training for the 2020 spring season.

What is egg oiling?

Egg oiling is a long-term strategy that reduces the number of resident Canada Geese on Truesdale and other lakes through physical intervention and behavior changes.

The physical intervention is the actual oiling of the eggs after mating has occurred but before the eggs have developed embryos. In our lake this typically takes place in late March or early April and can be pinpointed by observing the mating ritual of the local geese couples and finding their island nests about a week later.

Oiling works best with a crew of three working together. One person finds the nests, one person keeps the geese away from the nest, and one person oils the eggs. Oiled eggs are marked with sharpies to keep track of which ones have been treated. Records are kept for nests and eggs in each nest as a requirement of permission from the NYS DEC.

The behavior change for the geese is the most important long term consequence of oiling the eggs. We oil the eggs rather than simply break them because if the eggs are broken the goose simply lays more eggs. However, if the eggs are oiled, the development of the egg is stopped by preventing oxygen flow into the egg. This prevents the development of the embryo. Since the geese do not know this, they sit on the eggs for the 5-6 weeks it takes for hatching. When the oiled eggs do not hatch, the geese view it as a “failed nesting.”

Resident Geese bad, Migratory Geese good

In a successful nesting, the adults shed their flight feathers and take up residence with their new goslings on the lake, which is not what we want. In addition, other members of the flock who may have had failed nestings stick around to support the new parents in the flock.

In a failed nesting, they keep their flight feathers, take off, and head further south for the summer. They do not have the time to lay more eggs and have the goslings fledge and fly before the end of the season. This is what we want. These geese also do not develop a preference for returning to Lake Truesdale next summer and resume being Migratory Canada Geese rather than Resident Canada Geese.

Keeping the geese migratory means the problem is reduced both in the current year and in subsequent years. But other geese will take up residence on Truesdale if we stop oiling the eggs, so we must keep up the program to head off more future residents. We will also always have transient migratory geese — you can tell these geese since they are willing and able to fly away and visit other lakes since they do not have goslings to protect.

Oiling Results

In the last several spring hatching seasons, the crew of egg oilers has oiled over 100 eggs between the three islands each year. This has prevented the hatching of those eggs and has broken the resident behavior of those goose parents. To be successful, there has to be an initial oiling treatment and a follow up oiling treatment. Timing is the key to successful outcomes.

Egg oiling has made a huge difference in controlling the resident goose population on Lake Truesdale. When we first moved here in 1999, we would arrive home to 60-80 geese/goslings on our lawn. And easily double or triple that number on the lake. Lawns were covered in goose droppings. The beaches were favorite spots for goose gatherings. I have photos (deep in the archive) that I can dig up in case you think I am egg-agerating.

We have gotten it much more under control relative to those days — but we can always do better. Will you step up to help?

May 14, 2019
by rob
Comments Off on First Lake Treatment Set for Friday, May 17, 2019

First Lake Treatment Set for Friday, May 17, 2019

Fanboat surveying the plants of the lake. (Photo by Rob Cummings)

Truesdale Lake will be treated with the herbicide Clipper on Friday, May 17.

Our lake manager from Pond & Lake Connection will spray Clipper from their boat along the shoreline and in densely weeded areas.

Remember to turn off any irrigation coming from the lake for at least 24hrs.

A full description of Clipper is available at the following link –

May 7, 2019
by rob
Comments Off on Regional Lake Association Meeting Set for June 14 in Carmel

Regional Lake Association Meeting Set for June 14 in Carmel

Back by popular demand!  This year’s regional New York State Federation of Lake Association (NYSFOLA) Lower Hudson Lakes meeting will be on Friday, June 14, at the Sedgewood Club on the shores of China Pond in Carmel.  Thanks to Dora and Scott Keller, who arranged for us to use this venue. The meeting will start at 9:30 am and conclude around 2 pm. A light lunch will be provided.  The cost to attend is $5 per person.  

To sign up, please fill out the form at this link:  

From the organizers:

We have a great line up of speakers.  Maureen Galway-Perotti, a Master Gardener from the Putnam County Cornell Cooperative, will speak about shoreline buffers.  Steve Di Lonardo of Aquatic Ecosystems Consulting will share his insights on nuisance algae.  Kevin Fitzpatrick, the Director of Engineering from the East of Hudson Watershed Corporation, will talk about stormwater management and how that can protect your lake. One speaker from the past, Ken Belfer, will revisit to give a brief overview of the DEC pilot project at Mohegan Lake.  And we will be treated to a display of aquatic plants and a talk on aquatic plant control by AJ Reyes of Northeast Aquatic Research.  You will also have time for networking with other lake enthusiasts.

NYSFOLA regional announcement

If you are planning to attend, please let them know by May 31.  Your reservation helps them ensure enough seating and food.  Reserve your spot using this link: 

April 13, 2019
by rob
Comments Off on June 13, 2019 – Lakewide meeting – Drawdown Initial Results & 2019 Plan

June 13, 2019 – Lakewide meeting – Drawdown Initial Results & 2019 Plan

On Thursday, June 13 starting at 8:15pm at the South Salem Presbyterian Church, we will be holding a meeting open to all lake association and lakefront owners about the drawdown of Lake Truesdale.

The Pond and Lake Connection (the company that has managed Truesdale Lake weed and algae control for the past two years) attempted to draw down Truesdale Lake in the Fall of 2018 but they ran into technical, material, and weather difficulties that ultimately doomed the project for this past winter.

The unusually wet summer and fall of 2018 pushed the initial siphon pipe installation back several weeks from the original plan of mid-October. Once the siphon pipes were in, we received several very significant rainfalls that ended up filling the lake up faster than the pipes were able to drain it. The storms also disconnected the siphon pipes and interrupted the drawdown on several occasions.

2018 was a learning experience for us and Pond & Lake Connection and we will be doing an analysis of what went wrong and how to correct and account for it.

Some of the factors that need to be taken into account to correctly model the inflow to Truesdale Lake include:

That’s the easy stuff.

When the lake is at a higher level over the spillway, it drains faster. Every inch it goes higher increases the rate of outflow. The reverse is true as well.

Once the water level goes below the spillway height, the lake ceases to drain. The aim of the drawdown is to get the lake to a point 2-3 feet lower than the spillway height. How is this accomplished? Siphon pipes are what we are using.

To model the outflow in this situation, we need to know:

  • diameter of the pipe (6″ used in 2018, recommend 12″ pipe for 2019)
  • number of pipes used (4 used in 2018, 6-8 recommended in 2019)
  • speed of water flow
  • length of pipe
    • 12″ pipe is significantly more expensive than 6″ pipe
    • length of pipe impacts ability to siphon effectively
    • need more siphons and longer lengths of pipe

There are a number of other factors that impact flow rate that we will discuss. Using these, we can calculate estimated volume of flow over the spillway through the pipes. To be effective at lowering the lake level, this volume must be higher than the inflow rates. Complicating the real world results, the inflow rates can and do change on a daily basis due to rainfall and runoff.

Assuming we can get a volume of water out of the lake significantly exceeding the actual inflow into the lake, we will be able to achieve a drawdown. Once this has been achieved the questions that remain are:

  • how many days do we drain for to get to desired drawdown height
  • how long do the siphons stay in place for optimal drawdown impact
    • soil compaction,
    • freezing weed roots and seeds,
    • time to work on exposed waterfront {permits may be required!},
    • …etc
  • how long will the lake take to re-fill up to spillway height for spring

The meeting in June will be a chance for Pond & Lake Connection — along with the volunteers who are helping with the project — a chance to speak and answer questions about these calculations and plans for the upcoming season.

Hope you can come!