Blue Hole (Castalia)
The Blue Hole captured the public’s interest because of its size, about in diameter, clarity, vibrant blue hue, and enigmatic "bottomless" appearance. Contrary to prevalent belief, the depth of the Blue Hole is not unknown, but has been sounded and found to be about deep. Water temperature is about throughout the year. Floods and droughts have no effect on temperature or water level. The Blue Hole is fed by a passing underground stream which discharges of water daily into Sandusky Bay to the north, feeding into Lake Erie. The water contains lime, soda, magnesia and iron, and because the Blue Hole is anoxic, it cannot naturally sustain fish. The surrounding terrain is developed on limestone bedrock and exhibits karst topography due to dissolution of the limestone by ground water, creating water-filled sinkholes. The Blue Hole was known to American Indians and was first recorded in history in 1761. Several similar blue holes are known to local residents. The Blue Hole that once was a tourist attraction is now off limits to the public. It is located on the grounds of Castalia Trout Club. It is to be distinguished from another hole similar in size and eerie bluish-green color. This latter hole is owned by the Castalia State Fish Hatchery operated by the Ohio Department of Natural Resources, Division of Wildlife and is open for public viewing.
Blue Mountains (ecoregion)
This ecoregion extends from the Redmond area of Central Oregon, across a wide swath of the Columbia Plateau in Eastern Oregon, to Hells Canyon on the Snake River at the border of the three states. The ecoregion is named for the Blue Mountains and contains a complex of basins and mountain ranges that, at average 2100-2900m, are lower and more open than the neighboring Cascades and Northern Rocky Mountains but do include some steep landscape of which Hells Canyon at 1,660m is North America's deepest gorge. The mountains of the ecoregion include the Strawberry Range, Greenhorn, Elkhorn, Aldrich and Maury Mountains in the Blue Mountains, the gentler Ochoco Mountains to the west and the rugged Wallowa Mountains to the east. Rivers include the Grande Ronde, Powder Rivers and Malheur Rivers, all tributaries of the Snake and the John Day and Umatilla Rivers, tributaries of the Columbia.