Limestone Stream Map of Pennsylvania
Limestone streams are known for an abundance of large trout and an abundance of insect life. More insects means more food for trout, and more food means larger trout.
A new map of limestone streams is based on Professor Higbee's ® Stream & Lake Map of Pennsylvania. Considered to be the most highly detailed map of it's kind showing even the smallest tributaries. Now you can see both the limestone deposits and all of the streams that flow through them.
The new map shows where the underlying limestone deposit are in Pennsylvania. A high level of stream detail shows all creeks, rivers and even unnamed tributaries flowing through the limestone deposits highlighted on the map covering south-central and south-eastern Pennsylvania, the areas that contain almost all of Pennsylvania's limestone deposits.
Water flowing through the highlighted areas is more likely to incorporate a water flow from underground limestone caves or water that flows over limestone deposits. Streams containing limestone water have a pH that is less acidic than non-limestone streams, also called freestone streams.
Limestone is permeable and soluble. Over millions of years it is eroded by water. Weak carbonic acid in rainwater and acid rain from industrial sources reacts with the chemicals in the rock. Over time, the water filtered into the underlying depths of sediments and eroded the limestone forming hollow cavities which eventually formed limestone caves or caverns.
The continual seepage and flow of water through the limestone deposits results in underground streams and even rivers. Given enough time they can carve their way through a mountainside, creating openings and entrances to the outside. These streams then flow into the valleys containing dissolved limestone particles as limestone spring creeks. The limestone water can also rise and appear as natural springs. Other cave openings include pits, depressions, and sink holes that are located at the tops of caves.
Two examples of limestone streams flowing underground are Antes Creek near Jersey Shore, Pennsylvania, which Professor Higbee represented as a dotted line from the point it disappears until it rises again in the next valley. And, Fishing Creek goes underground for a while near Mackeyville, Pennsylvania.
Penns Cave, a popular tourist attraction near Centre Hall, Pennsylvania is the headwaters for Penns Creek where it actually flows from a limestone cavern. You can tour the cavern by boat and view the stalagmite and stalactite formations before the tour ends on pond that spills over to create Penns Creek. A creek considered by many to be the best limestone spring creek in the eastern United States. The year around temperature in the underground cave is 52 degrees. Water flowing from the cave down stream begins at an ideal temperature for trout. Water that is warmer in winter and cooler in summer.
Limestone streams are prime fly fishing waters
Low acid limestone streams create ideal conditions for both insect life, aquadic plants and large trout. Armed with a limestone map, maybe a pH water tester and water thermometer, you could potentially uncover some overlooked limestone gems containing big trout.
The average limestone stream has a pH of 6.5 to 8.0, where the non-limestone stream ranges from a pH of 4.0 to 5.5. Limestone is a natural buffer against the problem of acid rain and other acid sources like acid mine drainage. Water with an acidic pH is harmful to trout. An extreme alkaline pH is also harmful to trout. The pH scale runs from 0 to 14, battery acid is 0 and bleach or drain cleaner is 14. Water with a high alkalinity pH of 10 can cause lethargy and less feeding in trout.
The ideal for trout would be 6.5 to 8.0, the same as the average limestone stream.
How the map was created
Howard Higbee, former Penn State University Geology and Soils Professor also created the Pennsylvania Land Resource Map—a highly detailed record of the state's geology and soils types.
The infographic below describes the soils group unit types that indicate limestone deposits on the new map. Before Higbee's death in 1993 he showed map publishers Larry Seaman and Karl Ings of Williamsport, Pennsylvania how to locate the limestone deposits on his Land Resource Map. They used this information to create the Limestone Stream Map of Pennsylvania.
Pennsylvania has some of the finest limestone spring creeks in the United States. In fact, these unique streams attract anglers from around the world.