Meadow Run Natural Water Slides Traditional Geocache

The Natural Waterslide feature on Meadow Run is a popular summer destination for visitors to Ohiopyle State Park. The Natural Water Slides are a fun, but sometimes bumpy, way to get refreshed on a hot summer day. This should be a fairly easy find, however depending on the time of the year, you may encounter many muggles in the vicinity of the cache, please use extreme stealth when searching. Please consider giving a favorite point if you find this cache an enjoyable experience. You will begin the search hiking upstream on the yellow blazed trail. There will be no need to leave the trail to find the cache.

This naturally developed feature is an example of an erosional landscape formed by constant erosion from running water over millions of years. The rock forming the Natural Water Slide is a mass of Pottsville Sandstone, which is known for its resistance to erosion. However, streams are one of the most effective surface agents that erode rock and the powerful flow of Meadow Run stream has made its mark even in this erosion resistant rock.

Types of Stream Erosion:

Streams are one of the most effective surface agents that erode rock and sediment. Erosional landscapes such as the Grand Canyon have been formed by constant erosion from running water over millions of years. In addition to eroding the bedrock and previously deposited sediments along its route, a stream constantly abrades and weathers the individual rock and soil particles carried by its water. Hydraulic action, abrasion, and solution are the three main ways that streams erode the earth's surface.

Hydraulic Action. The ability of flowing water to dislodge and transport rock particles or sediment is called hydraulic action. In general, the greater the velocity of the water and the steeper the grade, the greater the hydraulic action capabilities of the stream. Hydraulic action is also enhanced by a rough and irregular stream bottom, which offers edges that can be “grabbed” by the current and that create uplifting eddies.

Abrasion. Abrasion is the process by which a stream's irregular bed is smoothed by the constant friction and scouring impact of rock fragments, gravel, and sediment carried in the water. The individual particles of sediment also collide as they are transported, breaking them down into smaller particles. Generally the more sediment that a stream carries, the greater the amount of erosion of the stream's bed. The heavier, coarser-grained sediment strikes the stream bed more frequently and with more force than the smaller particles, resulting in an increased rate of erosion. Circular depressions eroded into the bedrock of a stream by abrasive sediments are called potholes. The scouring action is greatest during flood conditions. Potholes are found where the rock is softer or in locations where the flow is channeled more narrowly, such as between or around boulders.

Solution. Rocks susceptible to the chemical weathering process of solution can be dissolved by the slightly acidic water of a stream. Limestone and sedimentary rock cemented with calcite are vulnerable to solution. The dissolution of the calcite cement frees the sedimentary particles, which can then be picked up by the stream's flow through hydraulic action.

Source: CliffsNotes.com. Stream Erosion. 27 Mar 2011 http://www.cliffsnotes.com/study_guide/topicArticleId-9605,articleId-9511.html

The Natural Water Slides on Meadow Run were primarily developed through Hydraulic Action. The velocity of the water, generated in large part by the high gradient of this section of Meadow Run, develops significant hydraulic action. The gradient is calculated by dividing the vertical height between two points by the horizontal distance. A high gradient indicates a steep slope and rapid flow of water (i.e. more ability to erode); whereas a low gradient indicates a more nearly level stream bed and sluggishly moving water. (Gradient = vertical height/horizontal distance)

Given the high gradient and the abrupt changes in the flow of the stream, water velocity is changed from point to point. The change of velocity is associated with changing hydraulic pressure. When internal hydraulic pressure decreases small bubbles are formed. When it increases the bubbles collapse violently and produces 'shock waves' that hammer the adjoining rock surface and pick up eroded particles. This process is known as cavitation. Cavitation is responsible for the formation of the hollows and potholes that can be seen in the bed of Meadow Run. The effects of cavitation are a significant factor studied in the engineering of manmade hydraulic systems. If not prevented, cavitation can destroy metal valves and damage even metal and concrete pipe. The ongoing cavitation action of the water on Meadow Run can be observed by visitors and felt if you choose to take a ride down the slides.

CLICK HERE TO RIDE THE SLIDES COURTESY OF LAURELHIGHLANDS.ORG.