Truesdale Lake  

South Salem, New York

May 24, 2020
by rob
0 comments

Egg Oiling Update #2

This is Update #2 for our 2020 egg oiling. To read the first update, click here. To read the initial posting about Truesdale egg oiling, click here.

Background

For Spring 2020 Truesdale Lake applied for and received a United States Fish and Wildlife Services permit for egg oiling. The permit number is FWS RCGR #13757A. More information about Canada Goose breeding control via egg oiling visit this link.

Status

There are three islands on the lake. From the north to the south they are: Waxwing Island, Ant Island, and Pirate Island. These are shown on the chart below.

Geese tend to nest on the islands because of the protection afforded from predators such as raccoons, foxes, coyotes, mink, and predatory birds.

Note: scale is for lake dimensions. Island dimensions are shown larger here than their true size.

Pirate Island Nests – Third Visit

On April 12, a return survey (third visit this season) of Pirate Island was done and found four goose nests (N1, N2, N3, N8) on the island. This is the same number seen during visit 2.

  • N1 southeast part of island. 10 eggs.
  • N2 southwest part of island. 3 eggs.
  • N3 northwest part of island. 6 eggs.
  • N8 north-center part of island. 6 eggs.

4/12 – Total eggs oiled on Pirate Island – 25 (24 intact).

Pirate Island Nest N1 – 10 eggs – April 12, 2020

Ant Island Nests – Second Visit

This reporting period resulted in many new nests on Ant Island. 21 total eggs in six nests.

  • N5 north tip of island with 5 eggs.
  • N10 (New) – SW on Ant Island with 6 eggs
  • N11 (New) – south center on Ant Island with 2 eggs
  • N12 (New) – south point on Ant Island with 3 eggs
  • N13 (New) – SE end of Ant Island with 4 eggs
  • N14 (New) – west side of Ant Island with 1 egg

Waxwing Island Nests – Third Visit

Found one new nest with three eggs on Waxwing Island. Total count is 4 nests and 22 eggs.

  • N4 – northwest end of island, 6 eggs.
  • N6 – southeast end of island, 6 eggs.
  • N7 – center of island, 7 eggs.
  • N9 (New) – center north of Waxwing Island with 3 eggs.

4/14 – Ant Island and Waxwing Island 43 total eggs in 10 nests.

April 24 Report

This reporting period combined two weeks and resulted in many changes as failed nests start to become evident and unhatched eggs from the abandoned nests are eaten.

Ant Island now has six fewer goose eggs from an abandoned nest, and nine more goose eggs for a total of 25 goose eggs.

There is a new Swan nest of eight eggs at the southwest end and a new Mallard Duck nest of nine eggs at the middle west side of the island – which were both left undisturbed.

Waxwing Island has three abandoned nests and sixteen fewer eggs for a total of only 6 goose eggs.

The Swan nest of eight eggs is still attended and was left undisturbed. Cygnets should be emerging very soon.

Here are the current nest designations and inventory for Ant and Waxwing Islands:

  • N4 – west tip of Waxwing Island with 2 eggs – abandoned
  • N6 – east tip of Waxwing Island with 0 eggs – abandoned
  • N7 – center west on Waxwing Island with 2 eggs – still attended
  • N9 – center north on Waxwing Island with 2 eggs – abandoned

  • N5 – north tip of Ant Island with 0 eggs – abandoned
  • N10 – SW on Ant Island with 8 eggs – attended
  • N11 – south center on Ant Island with 3 eggs – cold, unattended
  • N12 – south point on Ant Island with 5 eggs – attended
  • N13 – SE end of Ant Island with 6 eggs – attended
  • N14 – east side of Ant Island with 3 eggs – cold, unattended

Pirate Island nest – N9 – April 25, 2020

April 25 Pirate Island

Several nests were unattended and N3 had only one goose attending it. New nest N15 was noted in the northeast part of the island with six eggs. Total egg count 30 eggs.

  • N1 southeast part of island. 8 eggs.
  • N2 southwest part of island. 8 eggs.
  • N3 northwest part of island. 2 eggs.
  • N8 north-center part of island. 6 eggs.
  • N15 (New) northeast part of island. 6 eggs.

Final nest status – May 15

This is the briefest of reports since all of the fifteen goose nests found on the three islands have failed, with the exception of N1 (southeast and six eggs) attended on Pirate Island and N13 (east side and two eggs) attended on Ant Island, depicted in this photo.

All remaining eggs have been either addled or re-oiled. So far, we have spotted only one family with several goslings.

In contrast, last year, where egg oiling did not take place, at least ten Canada Geese families were spotted and goslings were too numerous to count. In addition since so many goslings were hatched, many geese with failed nestings also stayed to assist the flock in raising the broods.

The two male Mute Swans based on Waxing Island and Ant Island have been aggressively chasing geese away from their respective territory.

Summary of Egg Oiling in Spring 2020

At their egg population peaks, the islands had the following total eggs:

  • Pirate Island (south island) – 30 eggs counted at peak on April 25
  • Ant Island (middle island)- 25 eggs counted at peak on April 24
  • Waxwing Island (north island) – 22 eggs counted at peak on April 14

Total of all eggs at peak times: 77 eggs in 15 nests.

Combining the eggs and the parent couples from the 15 nests we believe we prevented a population of 107 geese and goslings (30 parents and 77 goslings) from summering exclusively on Truesdale Lake.

In addition, flocks of geese families summering on our lake would attract transient geese from their failed nestings to land and take up residence on Truesdale Lake, potentially adding even more Canada Geese to our summer resident population.

Hosting over 100 geese over the summer is something we absolutely want to avoid — and the efforts of our volunteers have met with success. If you are interested in helping next spring, please email lake@truesdalelake.com to get on our roster of volunteers.

We do have at least one pair of geese with goslings who slipped through our springtime search. We assume they were nesting on an isolated shoreline and not on the islands. We will also have unavoidable visits from transient Canada Geese throughout the season, but you will note the lack of goslings with these flying visitors. Since they don’t fledge their young on our lake, the possibility of them returning to raise a family here next year is reduced greatly.

This marks the close of the successful 2020 egg oiling campaign on Truesdale Lake! Thank you to Jill, Scot, and Rob for keeping on top of visits to the islands — and keeping track of the status of the nests and eggs for our end of the year required report to the US Fish and Wildlife Service.

April 5, 2020
by rob
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Egg Oiling Update

For Spring 2020 Truesdale Lake applied for and received a Fish and Wildlife Services permit for egg oiling. The permit number is FWS RCGR #13757A.

For more information on egg oiling and the purpose of it, please read this post and this page on the lake website.

Status

There are three islands on the lake. From the north to the south they are: Waxwing Island, Ant Island, and Pirate Island. These are shown on the chart below. Geese tend to nest on the islands because of the protection afforded from predators such as raccoons, foxes, coyotes, and mink.

Pirate Island Nests – First Visit

On March 26, a survey of Pirate Island was done and found three goose nests (N1, N2, N3) on the island.

  • N1 southeast part of island. 8 eggs. Oiled and marked all 8.
  • N2 southwest part of island. 4 eggs. Oiled and marked all 4.
  • N3 northwest part of island. 6 eggs. Oiled and marked all 6.

3/26 – Total eggs oiled on Pirate Island – 18

Waxwing Island Nests – First Visit

March 28 survey, One nest noted.

  • N4 northwest part of island with five (5) eggs. Oiled and marked all 5.

3/28 – Total eggs oiled on Waxwing Island – 5

Ant Island Nests – First Visit

April 4 survey, one nest noted.

  • N5 north tip of island with five (5) eggs. Oiled and marked all 5.

4/4 – Total eggs oiled on Ant Island – 5

Waxwing Island Nests – Second Visit

April 4: Three nests noted, one N4 noted prior, N6, N7 are new nests.

  • N4 (northwest) had six (6) eggs, up from 5 in prior visit. Oiled and marked all six.
  • N6 southeast end of island, six (6) eggs. Oiled and marked all six.
  • N7 center of island, seven (7) eggs. Oiled and marked all seven.

4/4 – Total eggs oiled on Waxwing Island – 19

Pirate Island Nests – Second Visit

April 5: four goose nests (existing N1, N2, N3, plus new N8) noted on the island.

  • N1 southeast part of island. 7 eggs. Oiled and marked all 7.
  • N2 southwest part of island. 5 eggs. Oiled and marked all 5.
  • N3 northwest part of island. 6 eggs. Oiled and marked all 6.
  • N8 north-center part of island. 4 eggs (3 were cold). Oiled and marked all 4.

4/5 – Total eggs oiled on Pirate Island – 22

We will continue to monitor the islands and track any changes.

Wrap

What we want to happen: The goal is to have as few goslings as possible — and to have the nesting geese pairs have a failed nesting. When there are no goslings, the geese leave the lake and migrate north to the Canadian tundra as a pair and tend not to return to the site of the failed nesting in future years.

This is what Canada geese did for thousands of years before we cut down forests and created lawns and golf courses that reminded them of the tundra and made them feel at home. We are trying to restore their natural migration patterns back to Canada.

What we don’t want to happen: If the goslings hatch, then the goose (female) and gander (male) shed their flight feathers and become residents of Truesdale Lake for the summer while their goslings grow and mature into adults capable of flight. If there are enough goslings hatched, even nesting pairs who fail to hatch any of their own eggs will shed their flight feathers and join the resident flock.

March 26, 2020
by rob
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2020 Geese Management

A new group of residents has recently taken over actively oiling goose eggs on the three big islands of Lake Truesdale for spring 2020. This is done to control the population of Resident Canada Geese on the lake.

Egg oiling requires a permit from the Fish & Wildlife Service (FWS) which we have obtained. Truesdale Estates Association has FWS RCGR (Resident Canada Goose Registration) permit #13757A.

We can add anyone from the lake community who is interested in helping! See below for more info.

March 26, 2020 on Pirate Island (southernmost island) mama goose guards her newly laid half-dozen eggs.

The program on Truesdale Lake started in 2008 and has been very successful in controlling the population of resident Canadian Geese on the lake. The number of geese was in the hundreds in the early and mid-2000s and the oiling program has been successful in reducing these to several dozen in the past 10 years.

In 2019 the program did not have anyone oiling the eggs and the resident geese population shot back up into the 70-80 range – and possibly more.

If you are interested in helping out, please contact us via email at lake@truesdalelake.com or via our Contact Form. The process is not too difficult and training is easy. We would need to add your name to our FWS permit before you can be involved with the oiling program.

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 1.) physical intervention and 2.) behavior changes.

Physical Intervention

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 Fish & Wildlife Service.

Behavior Change

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.

This is NOT the outcome we want.

It is important to get all of the eggs and all nests oiled – or as many that are found. If there are enough goslings in a flock, even other members of the flock who may have had failed nestings stick around and lose their flight feathers to support the new parents in the flock. This creates a resident flock for the entire summer.

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 the outcome 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.

Other geese will find and 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 past 10 years up to 2018, 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. There was 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?

March 1, 2020
by rob
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Drawdown Report 13

All Posts tagged drawdownreport – see all blow-by-blow updates (inclucing this post) as they were posted and communicated in late 2019 through early 2020.

Summary: January 25, 2020 marked the last day of drawdown target depth – where the lake’s level, in its fifth cycle, was three feet below the spillway ramp. The water began to rise after both 12” siphons had shut themselves down. The west siphon shut down early due to an enormous mass of fishing line and a fishing rod around tree limbs wedged against and inside the intake. See photos at the end of this report. 

When both 12″ siphons shut themselves down at the fifth target depth, reached on JAN 22nd, the lake refilled quickly in the next two weeks with only two inches of rainfall plus frozen ground and snow melt which greatly increased inflow from our vast watershed area. 

Our ‘Galapagos’ (the northwest normally submerged boat-pranging archipelago) is once again underwater (aerial view).
Map showing actual Galapagos Islands for comparison.
Our ‘Galapagos’ (the northwest normally submerged boat-pranging archipelago) is once again underwater (terrestrial view).
Aerial view of Indian Lane dam, spillway, and siphon tubes with drawdown level around 3 feet below spillway height in October 2019.

February 8th, 2020 marked the day the lake reached winter level when the water rose three feet back to the spillway ramp with the 6″ siphon still flowing. This represents a ratio of 18 inches of lake level rise for each inch of rainfall.

DD Month       Rain and       30-year       3-foot below Spillway

2019-2020     SWE total      average       Target Depth achieved 

SEP (dry)           0.6”            4.5”           1st – SUN 09/22/19

OCT (wet)          7.4”            4.6”           2nd – MON 10/07/19

NOV (avg)          3.1”            4.4”           3rd – TUE 11/07/19

DEC (wet)          6.3”            4.1”           4th – SUN 12/01/19

JAN (dry)           2.3”             3.7”           5th – WED 01/22/20

FEB (dry)           3.1”             3.0”           Weir Boards – FRI 02/14/20 

Note that December 2019 was quite wet and matched last year’s December 2018 total of 6.3 inches of rain. This graph was prepared by Janet Andersen, who operates the sister-gauge (NY-WC-6) to our Truesdale Lake precipitation gauge (NY-WC-22).

2018-2019 precipitation comparison chart showing 30 year average overlaid.
Ice-Out (lake thaw after a solid lake freeze) this year occurred Saturday 2/8/2020, which is the earliest of the past recorded six years, so no further beneficial effect from extended freezing would be gained by continuing the drawdown. 

For comparison, the recorded final Ice-Out dates for Truesdale Lake are:

2014 ~ APR 04

2015 ~ MAR 10

2016 ~ FEB 26

2017 ~ MAR 27

2018 ~ FEB 22

2019 ~ MAR 20

2020 ~ FEB 08  

I dove down after both siphons had shut down and the surface iced had melted. I found an enormous mass of vegetation and tree limbs wrapped in tangled fishing line and an entire broken fishing rod and reel against and inside the intake of the west siphon. Remember please, that all fishing from the bridge and the entire dam, all boatyards and all beaches and the entire exposed lakebed during drawdowns is prohibited.   

No fishing from the dam!
Climate change factors into our little local action to affect weed growth in Truesdale Lake. 2020 marked the warmest January in 141 years of NOAA recorded temperatures.
February 14, 2020 marked the day the lake reached its normal summer level, since the weir boards remained in place as the foundation for the anchored siphons. Only the smaller, 6″ back-up siphon is still flowing, and even if it continues to do so all year, it will have little effect on the overall lake level.  

Daily Observations:

1/10 FRI  LG -2.2’       Outflow exceeds inflow. Dry hydrant intake head exposed.

1/12 SUN  LG -2.5’     West 12” siphon shuts down. The 6’’ & east 12” siphons continue flowing.

1/13 MON  LG -2.4’    Winter Storm ISAIAH brings 0.27” rain. 

1/18 SAT  LG -2.7’      Winter Storm JACOB brings 3.2” snow with 0.4” SWE.

                                    Fire Dept works to extend the #8 dry hydrant intake head.

1/22 WED  LG -3.0’     Target Depth reached for the fifth time during this drawdown.

                                    East 12″ siphon shuts down.

1/25 SAT  LG -3.0’      4th day at target depth #5. Exposed beaches are compacted and frozen.

1/26 SUN  LG -2.0’     Lake level rises 12” after 1.15” rainfall & 0.4” snow melt.

1/31 FRI  LG -1.0’       Lake level rises another 12” with only 6” siphon outflow.

2/2 WED  LG -0.8’       Dry day #7 with inflow exceeding outflow. Ice melting.

2/5 WED  LG -0.5’       Lake rising and approaching spillway winter level. 0.12” rain.

2/6 THU  LG -0.3’        Lara’s Galapagos re-submerge until next drawdown.

2/7 FRI  LG -0.0’          Winter Storm KADE with 0.7” rain & 6″ siphon flowing.

2/8 SAT  LG +0.1’         ICE-OUT occurs. The lake level rises to the spillway ramp (normal winter level). Tree limbs tangled in fishing line and a fishing rod were found inside and against the west siphon intake, which was pulled free. 

2/10 MON  LG +0.3’     Winter Storm LAMONT, light lake freezing and brief flurries under “Full Snow Moon.”

2/12 WED  LG +0.5’     Winter Storm MABEL approaches.

2/14 FRI  LG +1.0’        Lake at Summer level after additional 1.7″ rain. Members who are not in the Polar Bear Club may want to wait before swimming. Lake is again available for resident-only fishing and sailing in boats with blue Truesdale Lake registration stickers. Fishing from beaches, boat yards and the bridge is prohibited.


Janet Andersen is the President of the Three Lakes Council (https://www.threelakescouncil.org/about-us/whos-who/) which was organized in 1970 to coordinate the environmental efforts for the Lake Waccabuc – Oscaleta – Rippowan watershed. Janet also operates the precipitation gauge in Twin Lakes Village and it is her data that I provided to Harold Ossher for 2018. (All the data for 2019 came from our Truesdale Lake precipitation gauge which began operation January 2019.) 

From: Janet Andersen

Date: Sat, Feb 29, 2020 at 4:31 PM
Subject: Re: Drawdown Report #13
To: Scot Evans

Scot – 

Thanks so much for continuing to keep me on copy and for the shout out on the precip graph.  

I’ve also been keeping daily lake levels (with an arbitrary zero) for a few years, but I haven’t been able to tie the lake level to the precip very accurately. Your number of 18″ for every inch of rain is amazing.   I’ve never been able to do this for our lakes with the snow / rain / evapotranspiration / dam leakage all involved.  Have you gotten an evapotranspirator gauge yet?  It’s only out during non-freezing weather.   And then we have beavers that sometimes dam up one, two, or three lakes – lots of factors make this too tough for me to feel confident about.   Do you have any idea of the acres of watershed : acres of lake ratio? I suspect the lake gain per inch of rain is seasonal, but it’s still a fascinating number.  

I’ve pasted a chart for this year’s precip. I’ll add the one for last winter, which was also benign. 

With great appreciation for the info you’re providing! 

Jan


Jan – Thanks for your note and your data!

Our watershed : lake ratio is 2380 acres watershed : 83 acre lake surface — or 28.7 : 1.  Here’s the relevant paragraph from our 2001 lake study:

“The portion of this watershed contributing surface runoff to the lake is large (2,380± acres, 963 ha), relative to the size of the lake (83 acres, 33.6 ha) (Figure 1). The majority of this watershed is located to the east of the lake and contains the Pumping Station Swamp. The size of the watershed creates a watershed to lake ratio of 28.7:1. The amount of rainfall draining to the lake was calculated using a runoff value of approximately 55 percent of precipitation (CT DEP 1982), an annual precipitation value of 47.5 inches per year (Soil Survey of Putnam and Westchester Counties, New York, 1994), and 68.6 cm (27 inches) per year of surface lake evaporation. Therefore, the net amount of rainfall that drains to the lake is large, (1.6 billion gallons) annually or an average daily flow of 4 million gallons per day. Thus, on an annual basis, the lake, with a volume of approximately 99,150,000 gallons, shows a moderate turnover rate (hydraulic residence time) of 16.2 times per year or every 22 days.”

Source: http://truesdalelake.com/projects/stormwater-management-projects/land-tech-2001-lake-evaluation/ (8th paragraph of report)

The flow rates are average over the year. For example at the end of our summer 2019 drought with our October rains, I suspect we had more absorption into our parched watershed soils for a few weeks until they became saturated again. Then when the additional rains came after then in Nov and Dec we likely got a higher % run off and a lower percent absorption. I am sure Harold and Scot will have the data to either confirm or dispute my suspicion. 

Take care, Rob

January 30, 2020
by rob
Comments Off on Notice of Consent – Annual Mailing Sent to Riparian Homeowners

Notice of Consent – Annual Mailing Sent to Riparian Homeowners

These annual notices were sent via US Mail to all riparian (lake-side) homeowners as required by New York State law. They are a continuation of our annual lake management program, including treatment, dating back over 50 years undertaken when we engaged Pond & Lake Connection as our new lake manager.

Date of Notice: 1/22/2020

Dear Riparian Property Owner:

To control the excessive growth of various aquatic weeds, at Truesdale Lake, The Pond Connection proposes to conduct an application of the aquatic herbicide/algaecide Cutrine Ultra, Green Clean Pro and Clipper.  A copy of these labels can be found at http://www.thepondconnection.com.  We anticipate the treatment to occur throughout the summer, only when necessary and will proceed only after the riparian owners obtains a permit for the treatment from the NYSDEC. 

This pesticide application will only occur if sufficient aquatic vegetation is present to warrant treatment and under favorable weather conditions. Prior notification of the exact dates of treatment can be provided by contacting The Pond Connection as listed below.  The pond/lake shoreline will be posted with signs the day of treatment. 

As an affected riparian owner/user, you have the right to consent or object to the restrictions of water use resulting from the proposed treatment. The water use restrictions associated with use of the above pesticides are below:

  • Swimming and bathing are prohibited for: No Restrictions
  • Fishing and/or fish consumption is prohibited for: No Restrictions
  • Livestock watering is prohibited for: No Restrictions
  • Irrigation or spraying of agricultural crops is prohibited for: Cutrine Ultra:N/A, Green Clean Pro: N/A Clipper: 5 Days.
  • Use of water for human consumption is prohibited till: Cutrine Ultra: 200ppb, Green Clean: 50ppb, Clipper: 50ppb.
  • Use of water for domestic purposes is prohibited till: Cutrine Ultra: 200ppb, Green Clean: 50ppb, Clipper: 50ppb.

Human consumption and domestic purposes restriction refers to the water body being used as your primary and sole use of water for drinking and culinary purpose.  Potable water use is not incidental contact with the water such as swallowing a mouthful of water while swimming.

You have twenty-one (21) days to respond to this notice. If you wish to object to the proposed treatment(s), please file a written document stating your objection to the proposed treatment and the water use restrictions resulting from the treatment.

Send your comments to the Bureau of Pesticide Management listed below:

NYS Department of Environmental Conservation, Region 3
Bureau of Pesticide Management
21 South Putt Corners Rd, New Paltz, NY 12561

If you wish further information about the treatment, or wish information on the exact dates of the pesticide application, please contact the following person:

  • The Pond and Lake Connection, 1112 Federal Road, Brookfield, CT 
  • Name of Contact Person: James Gorman
  • Telephone Number: 845-798-9383  Email: james@thepondandlake.com

If you do not respond to this notice, your lack of response will be considered consent to the proposed treatment. If you have any questions on the permitting process, please contact the Department representative listed above.

January 14, 2020
by rob
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Drawdown Report 12

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.

Today, with all siphons flowing, the lake level is 2.3 feet below the spillway ramp and descending. The lake froze completely on December 20th with ice up to three inches thick and 80% of the lake was melted by January 7th, allowing for a much cleaner fifth and final descent to target depth. If we are lucky, the lake will again freeze in January when the siphons shut down with lake level at three feet below the spillway. 

Also today, the dry hydrant intake head became exposed for the fifth time during this season’s drawdown. The Fire Commissioner’s contractor may agree that this Monday through Thursday, 1/13 – 1/16, with above freezing temperatures, would present an ideal opportunity to install an extension in order to lower it vertically at least two feet more.

dry hydrant intake head

And finally, today marks a milestone confirmation of the calculations from our resident mathematician, Harold Ossher, in that the two 12” siphons and one 6” siphon, installed and maintained by James Gorman of P&LC, have demonstrated that they are ideal in size and number for reducing the lake’s level during the 30-year average rainfall of 4.4 inches per month within the three-month drawdown period – October, November and December.

This conclusion is reached from observations in these last two reporting periods, in that all three siphons have been flowing consistently for the past 30 days – WED 12/11 to FRI 1/10 – with inflow from 4.38 inches of rain, which represents one drawdown month.

With all three siphons flowing uninterrupted, the lake’s level increased after each rainfall from 1.3 feet below the spillway up to two and a half inches above the spillway, and it descended during the dry days with a net decrease of 12 inches to 2.2 feet below the spillway. 

DD Month       Rain/SWE    30-year      3-foot below Spillway

2019-2020      inch total    inch AVG    Target Depth achieved

SEP   (dry)         0.6           4.5            1st – Sunday 9/22

OCT  (wet)         7.4           4.6            2nd – Monday 10/7

NOV  (avg)         3.1           4.4            3rd – Tuesday 11/7

DEC  (wet)         6.3            4.1            4th – Friday 11/29

JAN   (dry)    (0.4 to date)    3.7           5th – Friday 1/17

December 2019 was quite wet and matched last year’s December 2018 total of 6.3 inches of rain.

Some of the desired results from the drawdown, like weed tuber destruction and soil desiccation, may be evident as early as the end of next summer. Other long-term benefits, such as silt compaction, will take more time and can be assessed later on. 

In the meantime, lakeside residents have made excellent progress in cleaning up their newly exposed beaches, removing broken glass and other hazardous objects, and disposing of trash, including discarded equipment, at their own expense. 

Many neighbors have sent photos of their newly cleared lakefronts to be included in the Truesdale Lake archives.

This is my final report for the 2019/2020 winter season drawdown. Rob Cummings has compiled all of the drawdown reports and replies in one link on the Truesdale Lake website > http://truesdalelake.com/tag/drawdownreport/ 

Scot

Daily Observations during this reporting period:

12/23  MON   LG -0.5’          Outflow exceeds inflow. Lake 100% frozen with 3″ ice.


12/24  TUE    LG -0.7’          Outflow exceeds inflow.

12/25  WED   LG -0.9’          Outflow exceeds inflow.

12/26  THU    LG -1.1’          Outflow exceeds inflow.

12/27   FRI     LG -1.3’          Outflow exceeds inflow.


12/28  SAT     LG -1.5’          Outflow exceeds inflow. 0.01” rain

12/29  SUN    LG -1.7’          Outflow exceeds inflow. 

12/30  MON   LG -1.7’           Inflow matches outflow. 0.63” rain


12/31  TUE    LG -1.5’           Inflow exceeds outflow. 0.44” rain

1/1      WED   LG -1.3’           Inflow exceeds outflow. 0.02” SWE

1/2      THU    LG -1.3’           Inflow matches outflow. Lake ice continues to melt.

1/3       FRI     LG -1.5’          Outflow exceeds inflow. 0.07” rain


1/4      SAT     LG -1.7’          Outflow exceeds inflow. 0.11” rain

1/5      SUN    LG -1.7’           Inflow matches outflow. 0.05” rain

1/6      MON    LG -1.8’          Outflow exceeds inflow. 0.01” SWE


1/7      TUE     LG -1.9’          Outflow exceeds inflow. Lake ice 80% melted.

1/8      WED    LG -2.0’          Outflow exceeds inflow. 0.03” SWE. Lake nears target depth.

1/9      THU     LG -2.2’          Outflow exceeds inflow. Siphons perform as calculated.

1/10     FRI      LG -2.3’          Outflow exceeds inflow. Dry hydrant intake head exposed.


Scott, many many thanks for this and all previous reports, and Rob for collecting and publishing them on the website. It’s been great to have such detailed, ongoing information about how the drawdown has proceeded. I also really appreciate your having a found a 30-day period that helped to verify that the calculations were close to matching reality.

Based on our experience this year, so well recorded, I have some thoughts for next year about preventing the lake from rising so much above the 3′ drawdown level so frequently. I look forward to discussing them in due course.

Thanks, Harold


Scot, 
Thank you for sharing this information with me I will pass it along to our contractor and my collogues. The board of fire commissioners has chosen a contractor to do the repairs on the dry hydrant. When the contractor notifies me of a start date I will share that with you. 

Best Regards, Mike Lombardi Fire Commissioner


Scot & Skip, 

The contractor for the Fire District plans to start the repair and extension project for the Truesdale lake dry hydrant tomorrow. If anyone has any questions feel free to contact me. (914) 588-8270.

Best Regards, Mike Lombardi Fire Commissioner


(after extension of dry hydrant)

Hi Mike,

I enjoyed meeting you at the boatyard and observing the final flow test. 
Many thanks to you from all of us for the completed extension and nicely buried and deepened intake section. 
And congratulations on your successful flow test today!

Scot

December 28, 2019
by rob
Comments Off on Drawdown: Report 11A

Drawdown: Report 11A

Greetings James,

This is ninth dry day of our break following all that pesky rain.

All your siphons are churning away nicely.

The lake ice continues to melt with rain arriving Sunday night, through Monday. 

The lake level lowered at a rate of two inches per day during this dry spell (18” in nine days).

The 3” ice cap messed up the top of my tenths-graduated gauge, but today, the lake is 1.3 feet below the spillway and descending. 

Enjoy your weekend!

Scot


Good news!
–James

December 23, 2019
by rob
Comments Off on Drawdown: Report 11

Drawdown: Report 11

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.

Summary: This four-week report involved so many environmental changes that I had to wait to complete it until a break in the weather – the dry spell we’re experiencing – now in its third day. We received so much rain this month that the lake level rose 38 inches after receiving five inches of rain and Snow/Ice Water Equivalent (SWE), even with all siphons flowing much of that time.

When flowing, all three siphons draw nearly 12 million gallons of water out of the lake each day, so you can imagine how much water must flow in to continue increasing the lake level even while they are working.
The lake is now frozen, so we can observe what happens next when the water is pulled out from below the ice. If the ice doesn’t melt during the upcoming 40-degree days, it may start to cave in under its own weight through the air spaces up to the three-foot target depth. This may make access to the middle of the lake for ice skating and ice fishing rather challenging. 

On the up side, if the ice cap over the siphons descends with the lake, it may help to prevent the whirlpools above the siphon intakes that form when target depth is near (see photo). 

Siphon Whirlpool beginning to expand

You have probably noticed that the lake rose to its maximum level of three inches above the spillway ramp elevation a few days ago, even with all the siphons flowing. Once again, this demonstrates that we’ll have no difficulty filling the lake back up in the spring as water flows from West Mountain heights down to our oasis.

LG +0.3

The small 6” siphon continued flowing all by itself during the first two weeks of this reporting period. When the lake level rose from target depth to 2.8 feet below the spillway on December 1st (photo below), we requested that P&LC return to restart both 12″ siphons when the lake rose one more foot, which occurred ten days ago. P&LC restarted both 12″ siphons right on schedule – on the 10th & 11th of December – to keep up with the inflow. They will continue working until the 3-foot target depth can be reached for the fifth time.

LG -2.8 on 12-1-2019

While trees are without leaves, I’ll arrange a visit to Ridgefield Academy to take a photo of the lake from West Mountain and post it on NextDoor and in the next report so all can see that we live in a watershed valley.  

Rain Total30 YR AVG3 ft target depth achievedLake freezes completely
SEP 0.6″ 4.5″1st – Sunday 9/22
OCT7.4″4.6″2nd – Monday 10/7
NOV3.1″4.4″3rd – Tuesday 11/71st – Sunday 12/8, then melts
DEC5.3″ (to date)4.1″4th – Friday 11/292nd – Friday 12/20 solid

When December ends in ten days, rain and SWE may match last year’s wet December that totaled 6.33 inches. Today, with all siphons flowing, the lake level is two inches below the spillway ramp and descending.

Daily Observations:

Precip as of Winter Solstice in 2019

TUE     11/26        LG -2.5        Outflow exceeds inflow with all siphons flowing.
 WED    11/27        LG -2.7′       Outflow exceeds inflow with all siphons flowing. 
THU     11/28        LG -2.9’       Outflow exceeds inflow where the west 12″ siphon shuts down naturally.
FRI       11/29        LG -3.0’      Target Depth is achieved where the east 12″ siphon shuts down naturally.
SAT      11/30        LG -2.9’       Inflow exceeds outflow with only the 6″ siphon flowing.
SUN     12/1          LG -2.8’       Inflow matches outflow as Winter Storm Ezekiel approaches.
MON    12/2          LG -2.7’       0.77″ rain where Inflow matches outflow.
TUE      12/3         LG -2.5’       0.20″ rain where Inflow exceeds outflow as coastal low pressure cell 
                                                 moves in with steady light rain.
WED     12/4         LG -2.4’       Inflow exceeds outflow.
THU      12/5         LG -2.3’       Inflow exceeds outflow with salt added to each siphon frozen discharge.
FRI       12/6          LG -2.2’       Inflow exceeds outflow.
SAT      12/7          LG -2.2’       Outflow matches inflow.
SUN     12/8          LG -2.2’       Outflow matches inflow where 100% lake is frozen.
MON    12/9          LG -2.1’        0.37″ rain where inflow exceeds outflow where lake ice completely melts.
TUE      12/10       LG -1.3’        0.88″ rain where inflow greatly exceeds outflow with heavy rain. 
                                                  P&LC restarts both 12″ siphons. (east shuts down)
WED     12/11       LG -1.3’        0.58″ rain where Inflow exceeds outflow after receiving 0.87” rain.
                                                  P&LC restarts east 12″ siphon.
THU      12/12       LG -1.3’        Outflow matches inflow with all siphons flowing well.
FRI       12/13       LG -1.3’        Outflow matches inflow with all siphons flowing.
SAT      12/14       LG -0.5’        1.47″ heavy rain where inflow greatly exceeds outflow and all siphons flowing.
SUN     12/15       LG -0.2’        0.7″ light rain where inflow exceeds outflow with all siphons flowing.  
MON    12/16       LG 0.1’       Level rises over spillway ramp for the first time this drawdown.
TUE     12/17       LG 0.2’’       Inflow exceeds outflow with all siphons flowing.             WED    12/18       LG 0.2’’       Inflow matches outflow with all siphons flowing.
           THU     12/19       LG 0.1’’       Outflow exceeds inflow with all siphons flowing.
           FRI      12/20       LG 0.0’’           Lake level descends to spillway ramp height. 
           SAT     12/21        LG -0.1’’        Outflow exceeds inflow with all siphons flowing.

           SUN     12/22       LG -0.2’’        Outflow exceeds inflow with all siphons flowing.  

This report is set to launch upon the occurrence of Winter Solstice – at 2319 EST.

Happy Holidays to all,
Scot


Should we issue a warning to stay off the ice due to the risk of it collapsing as the drawdown continues?

–Lara


Hi Lara,

Good question and there are two aspects to consider here. 

The first aspect is considering the effect of the drawdown with regard to the ice. The ice cannot support it’s own weight since it is flat and not shaped like an arch. The ice sheet will descend with the lake from the center out toward the perimeter. The air pockets and stress relieving ice breakage will occur in the perimeter areas where the exposed lakebed is already documented. The only risk to the resident is in navigating the broken ice and craters in order to get beyond the exposed lakebed perimeter on the way toward the center for good skating and ice fishing. So the risk for 90% of the lake will be the same as it has always been. Passing along this information may be better than issuing a warning to stay off the ice altogether, unless the board is concerned with potential liability. 

The second aspect is the classic monitoring and reporting of ice conditions so residents can make their own decisions as well as assume the risk for skating or ice fishing. 

Meghan Crystal has posted a question about ice conditions on NextDoor. So regarding your question above, I’ll answer with a post about today’s conditions only. Please let me know if you want to post a caution regarding the future or if you want me to.

Scot