The Water Table
Rain that falls on the surface seeps down through the soil and into a zone called the zone of aeration or unsaturated zone where most of the pore spaces are filled with air. As it penetrates deeper it eventually enters a zone where all pore spaces and fractures are filled with water. This zone is called the saturated zone. The surface below which all openings in the rock are filled with water (the top of the saturated zone) is called the water table. The water table occurs everywhere beneath the Earth's surface. In desert regions it is always present, but rarely intersects the surface.
Springs
A spring is an area on the surface of the Earth where the water table intersects the surface and water flows out of the ground. Springs occur when an impermeable rock (called an aquiclude) intersects an permeable rock that contains groundwater (an aquifer). Such juxtaposition between permeable and impermeable rock can occur along geological contacts (surfaces separating two bodies of rock), and fault zones.
Springs are a natural source of groundwater discharge at a rate high enough to form a channel on the earth's surface. The physical and chemical composition of spring water reflects not only the mineral composition of the various rock strata with which the water has been in contact but also the various chemicals that percolate into groundwater.
This spring is one of many springs located throughout the karst region of Kentucky. The bedrock is limestone, the sedimentary rock, mainly composed of calcium carbonate, can be dissolved by naturally acidic rainwater, forming underground openings that serve as drainage systems. These drainage systems can form aquifers that feed springs. This spring is known as a perennial spring, it continuously flows forth with fine limestone water.
One of the ways that springs are classified is by the volume of the water they discharge. Many springs are measured regularly, while some have never been measured. The largest springs are called "first-magnitude," defined as meaning they discharge at least 100 cubic feet of water per second (cfs), or about 64.6 million gallons per day (mgd).
The scale for spring flow is as follows:
- 0 Magnitude - no flow (sites of past/historic flow)
- 1st Magnitude - > 100 cubic feet per second (cfs)
- 2nd Magnitude - 10 -100 cfs
- 3rd Magnitude - 1 - 10 cfs
- 4th Magnitude - 100 gal/min (gallons per minute) - 1 cfs (448 gal/min)
- 5th Magnitude - 10 to 100 gal/min
- 6th Magnitude - 1 to 10 gal/min
- 7th Magnitude - 1 pint to 1 gal/min
- 8th Magnitude - Less than 1 pint/min
To log this cache, estimate, or collect and measure the rate of water flow from the spring. What magnitude would you classify this spring? E-Mail me the answer.
Pictures of yourself with your GPSr are appreciated and welcomed but not needed to log.
This cache placed and maintained by a Geocky member.
~ Woo Hoo! ~
CONGRATULATIONS to Cav Scout for the FTF!