The Largest Kettle on Long Island
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Note 2021: I have just been told that there is a $15 entrance fee to get into the park. Please take this knowledge into consideration before you plan to visit.
A kettle (or kettle hole) is a small, often round depression formed as a result of glacial movement. It is formed when a large piece of ice breaks away from the edge of a retreating glacier, and becomes partially buried under sediment deposited by the glacier. After it melts, this fragment leaves a depression in the landscape. A Kettle Pond or Kettle Lake is formed when water fills up the kettle hole. Kettle holes range from 5 m/15 ft to 13 km/8 mi in diameter, and may exceed 33 m/100 ft in depth. Most kettles are circular in shape because melting blocks of ice tend to become rounded; distorted or branching depressions may result from extremely irregular ice masses. Two types of kettles are recognized: a depression formed from a partially buried ice mass by the sliding of unsupported sediment into the space left by the ice, and a depression formed from a completely buried mass by the collapse of overlying sediment. In the United States, kettle holes are common in Wisconsin, Minnesota, New England and New York. The surface of Long Island is made up of many varied and interesting landforms. Each natural land feature originated through the action of some past or present geologic process. On Long Island these processes can be grouped into three categories -pre-glacial, glacial and post-glacial, depending on whether they occurred before, during or after the advance of a continental glacier onto the Island. Lake Ronkonkoma is in Suffolk County, New York. The community name derives from Indian term for "boundary fishing place.” Actually, Lake Ronkonkoma is not a lake. Geologically, it is a kettle hole. When glaciers covered a large part of the earth, a glacier covered the northern section of Long Island. As the glacier moved, it carved out this large hole, now Lake Ronkonkoma. Lake Ronkonkoma was formed when a large block of ice became detached from the glacial front during the Pleistocene Glaciation, an event that occurred some 17,000 years ago. After the ice retreated, it left a depression. This pit, or depression, formed when this block of ice from the receding glacier became isolated and buried in glacial debris (till). As the block melted the till collapsed to form a hollow, which became filled with water to form a kettle lake. Lake Ronkonkoma is the largest of eight kettle lakes located throughout Long Island. The 243 acre Lake Ronkonkoma is Long Island’s largest freshwater lake that was formed by a glacier. Scores of these lakes dot the northern half of Long Island. Their sizes are dependant upon the size of the original ice blocks and vary from a three-fourths mile diameter for Lake Ronkonkoma to ponds only twenty to thirty feet across. Lake Ronkonkoma varies in size from approximately 215 acres during average drought periods to 275 acres during flooding conditions. The average depth of the lake is approximately 14.5 feet deep, with two deep holes in the southwestern section (45 feet and 90 feet). The elevation of the lake surface is given as 55 feet (17 m) on the most recent USGS map, but as the lake is a "groundwater lake," not fed by streams, it has no surface outlet and its water surface reflects the current level of the local water table. This can undergo significant changes over time and the lake level experiences slow periods of rise and fall. In the late 1960s it was quite low; after several intermediate changes in level, in 2007 the lake was higher than at any time since, with a difference of well over five feet between the 1960s low and the 2007 high. When the kettle was created, ground water filled the hole that was deep enough to tap the underground water table. This accounts for the water always being fresh. It would be virtually impossible to drain the lake even with years of pumping. To claim credit for this earthcache, email the answers to these 3 questions to the CO. Please do NOT post the answers in your log so that it is fair for everyone who visits this earthcache. Go to the posted coordinates. You will be at the Lake Ronkonkoma County Park. The coordinates should bring you to a bench by the lake. (EDIT 7.12.12... the bench is no longer in that location; it's about 200 feet away. You can still do this earthcache by using the coordinates, though). [Sit down and enjoy the scenery. While you are sitting on the bench,] plug these coordinates into your GPSr: N 40 49.303 W 073 07.131. These coordinates are for a waypoint on the opposite shore. 1. Determine the distance in meters from the bench to the waypoint on the opposite shore. (hint: use a conversion program on any search engine to go from miles/fraction of a mile to meters). 2. Using this data as the diameter of the lake, calculate the approximate circumference of the lake. In circles, the circumference is 3.14 (pi) times the diameter. Thus the formula looks like pi(d). 3. How large do you think the chunk of ice was that created Lake Ronkonkoma? Explain how you arrived at this answer with some reference to scientific or mathematical reasoning. (i.e. saying “HUGE!” is not an acceptable answer!) ...AND... post the obligatory photo of you and/or your GPSr with a portion of the Kettle Lake in the background. Not geologically-related information, but interesting local legends and myths of Lake Ronkonkoma nevertheless: Lake Ronkonkoma has been called a place of haunting mystery. Lake Ronkonkoma was considered a most sacred lake by the Indians and it was also their meeting point. The lake is the subject of several Indian legends and myths, mainly rooted in the area's rich Native American heritage. For example: 1. It's bottomless (and/or empties into the Long Island Sound or other waterways). In fact, the lake is relatively deep (approx. 100 feet) at its southeastern side. 2. Every year the lake sacrifices someone. Specifically, "The Lady of the Lake" calls young men out to the middle of the lake and drowns them. In all versions, the lady is an Indian princess who herself drowned in the lake, for reasons that vary depending on the story. 3. There has always been speculation and wonder about its source of fresh water and its unexplained tendency to rise and fall periodically with no apparent relationship to the local rainfall. 4. The most popular story is that every year two lovers from somewhere in the area are killed by the Native American princess. Usually it is in an automobile accident because of the angry spirit. Other accounts involved the princess revisiting the lake, walking on water and taking the life of a man annually in search of her forbidden love. Her ghost is said to dwell in the depths of the lake, and some say each year, the princess drags down a least one young man to be her lover in death. This thought is considered the basis for the curse that at lease one person shall drown in the waters of the lake each year. While locals will confirm that drowning incidents are frequent at the lake, it is difficult to conclude whether or not deaths occur annually as the legend portends. Still, certain locals and historians will claim that almost every year for 200 years someone has drowned in Lake Ronkonkoma . . . almost always a male. and... many thanks to Geosliders, who pointed out to me that one drives over an esker to get to GZ, which is another glacial feature!
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