Walt Disney World - Bay Lake EarthCache

Bay Lake is more than just a scenic backdrop to Magic Kingdom and Disney resorts — it’s a window into Florida’s ancient geological history. This natural freshwater lake is part of a karst landscape, formed by the slow dissolution of limestone bedrock over thousands (or even millions) of years.

Bay Lake is classified as a sinkhole lake, a common feature in central Florida. Over time, slightly acidic rainwater and groundwater dissolved the underlying limestone, causing the surface to collapse and form a deep basin. Unlike artificial lakes built for aesthetics or irrigation, Bay Lake is a natural feature — rare within the highly modified landscape of Walt Disney World.

🧪 Geologic Background:

Florida sits atop a thick platform of carbonate rock, primarily Ocala limestone, which formed in warm, shallow seas during the Eocene Epoch about 22 million of years ago. Below is a map of the extent of sinkholes and their formation in Florida. Note the red circle, which is the approximate location of Bay Lake, which is within a blue zone indicating prevalent sinkholes.

As rainwater — made slightly acidic by absorbing carbon dioxide — seeps into the ground, it chemically weathers and dissolves this limestone, forming underground voids and caverns. When the ceiling of one of these voids collapses, it creates a sinkhole. If the sinkhole fills with water from rainfall or underground springs, it becomes a sinkhole lake, like Bay Lake.

Bay Lake is notably deep (up to ~35 feet in some areas), with steep sides — classic indicators of sinkhole origins. It also has no major streams feeding or draining it, relying instead on groundwater exchange, another hallmark of karst lakes.

🐟 Ecological Note:

Because of its natural origin, Bay Lake supports a relatively healthy freshwater ecosystem. Disney even uses it for controlled catch-and-release fishing. Aquatic plants, largemouth bass, bluegill, and other native species thrive here, thanks to the lake’s groundwater-fed clarity and quality.

🪨 How the Limestone Formed Beneath Bay Lake

🌊 Florida Was Once Underwater

• 60 to 100 million years ago, much of what is now Florida was submerged beneath a warm, shallow sea.

• Over millions of years, the shells and skeletons of marine organisms — like coral, mollusks, and microscopic plankton — accumulated on the sea floor.

• These remains were composed primarily of calcium carbonate (CaCO₃).

🏗️ Formation of Limestone

• As more and more sediment piled up, the weight compressed the lower layers.

• Over time, the loose calcium carbonate sediments were compacted and cemented into solid rock, forming limestone — a type of sedimentary rock.

• This process created the Floridan Platform, a thick layer of porous limestone that underlies most of the Florida peninsula. Below is a map of the Ocala Limestone (in red) which can be found within the central part of the state (blue).

🧽 Porous and Soluble Nature of Limestone

• The limestone is highly porous (meaning water can pass through it) and chemically reactive with acids.

• When rainwater absorbs CO₂ from the atmosphere and soil, it forms carbonic acid (H₂CO₃) — weak, but enough to dissolve limestone.

• Over long periods, this leads to the formation of:

  • Caverns

  • Underground channels

  • Sinkholes

  • And, eventually, sinkhole lakes like Bay Lake.

💧 How Bay Lake Is Fed by Groundwater

Bay Lake has no major surface inflows or outflows — no visible creeks or rivers entering or exiting. Its water levels remain relatively stable year-round, which is unusual unless it’s connected to a steady source. That source is groundwater, which moves through the Floridan Aquifer System.

🧠 How It Works:

1. Rainfall:

   • Rain falls across central Florida and soaks into the ground (infiltration).

   • Thanks to Florida’s sandy soils and porous limestone, this water easily reaches the Floridan Aquifer, an enormous underground reservoir.

2. Aquifer Recharge:

   • Water collects in underground cavities and flows through the limestone like a slow-moving river.

   • This recharges the aquifer and maintains high groundwater levels.

3. Seepage into Bay Lake:

   • Bay Lake’s basin cuts into this porous limestone, allowing water from the aquifer to seep into the lake.

   • This process is subtle but continuous.

   • During dry periods, the lake may even lose water back to the aquifer (depending on water pressure differences).

🧪 Evidence Supporting Groundwater Feeding:

• Clear water — groundwater-fed lakes are often clearer due to fewer sediments or surface runoff.

• Stable levels — unlike rain-fed ponds, groundwater lakes don’t fluctuate much unless there's a long drought.

• No streams — natural lakes with no visible inlets or outlets are almost always groundwater-influenced in karst regions

Works Cited

https://www.wdwconnection.com/bay-lake-creation-construction/

https://disneythemeparks.fandom.com/wiki/Bay_Lake

https://en.wikipedia.org/wiki/Bay_Lake_(Florida_lake)

https://en.wikipedia.org/wiki/Ocala_Limestone

https://edis.ifas.ufl.edu/publication/UW208

https://pubs.usgs.gov/ha/ha730/ch_g/G-text6.html

https://attractionsmagazine.com/disney-lakeshore-lodge-2027-river-country/

https://www.usgs.gov/water-science-school/science/sinkholes

TO LOG A FIND ON THIS CACHE YOU MUST ANSWER ALL THE QUESTIONS BELOW. YOU CAN CONTACT ME THROUGH MY EMAIL OR THE GEOCACHING MESSAGE CENTER TO SEND YOUR ANSWERS. ANY INCORRECT ANSWERS MAY RESULT IN A CLARIFICATION RESPONSE FROM ME.

1. "Walt Disney World - Bay Lake" on the first line of your email AND list all geocaching names of your party so I can match your answers to them. If you all want to learn something, I would prefer each cacher send me individual emails in the spirt of earthcaching.

2. Take a photo of you (or your signature item if you don't want to show your face) with Bay Lake in the background from the posted coordinates. This photo MUST be uploaded to your "found it" log. Please do not send any photos through the message center as Groundspeak compresses images. Each log MUST have a unique and different photo. No two logs may contain the same photo.

3. How would you describe the shape of the shoreline around the lake? Would you describe the shoreline as rounded, irregular, or elongated?

4. How would you describe the slope of the shoreline around the lake? Do you observe steep edges or gradual slopes?

5. (a) From the posted coordinates, do you see any visible inlets (creeks, rivers) or outlets from Bay Lake? (b) Based on your observations, do you think the lake is fed more by surface water or groundwater? Explain your reasoning.

6. Based on your previous answers, what evidence do you observe that would suggest a sinkhole is present here? Explain your reasoning.