Keystone Artesian Well EarthCache

An artesian well allows water to rise to the surface that has traveled through porous rock from a higher elevation. This pumpless well seems to defy gravity because the pressure that builds up between layers of rock gets relieved when the water finds a path to the open air. For nearly a thousand years, people have drilled wells to drink such cold, filtered water that doesn't need to be hauled up from the depths.

An aquifer provides the water source for an artesian well. An aquifer is the layer of permeable rock, like limestone or sandstone, that absorbs water from an inlet path at high elevation such as the top of a mountain. The water source might be fed by snowmelt or precipitation. Porous stone is sandwiched between a top and bottom layer of an impermeable substance like clay soil or shale rock. This keeps the water pressure high, so that when you get to a point below the entryway of the flow, there is enough pressure to bring the water up. Natural springs form in the same way when a gap in the impermeable rock, maybe triggered by an earthquake, allows the water to rise to the surface.

Entire cities have relied on giant underground aquifers to provide fresh, cold water when there are no above-ground rivers. In 1126, monks used a rod with a sharp end, called a bore, to penetrate a layer of impermeable rock. Their percussive drilling, just hammering on the end of the bore, broke through with sheer human force. The water that rose had percolated through the pores of the rock, so that many contaminants have been filtered out, and it proved safer to drink than standing or river water.

Nowadays, if a town or residence needs water closer to the top of a mountain, they might lie above the line where there is enough pressure to push the water all the way to the surface. In this case, the aquifer can be accessed by drilling a relatively shallow well and then pumping the water up to ground level. Our well-drilling has progressed from hammers and bores, to machinery that twists a giant drill into the ground. Sometimes, if the pressure is especially strong, because the well is lower in elevation, the water might thrust up like a fountain, and form a geyser.

The primary sources of usable water is Pennsylvania include rainwater , stream inflow from other states, surface water (stored in lakes, streams, and ponds), and groundwater. In 1966, it was estimated that Pennsylvanians use approximately 6.6 billion gallons of water per day and there is approximately 80 trillion gallons of groundwater and only 2.5 trillion gallons of surface water (DCNR, Educational Series 3: " The Geology of Pennsylvania's Groudwater"). Below the freshwater aquifer, the bedrock contains salt or brine water. This brine water is likely water that was trapped in the formation or material during deposition.

Because of the rural nature of Pennsylvania, groundwater provides approximately 85 percent of the water used for human consumption, but because it is difficult to see how water moves through the soil, unconsolidated material (sand and gravel) and bedrock, it has mystified individuals. For some homeowners, they believe that the groundwater comes from a vast underground lake or from underground streams that come from Canada, Virginia, Vermont, or even Maine. Even through there is a large database of information on groundwater in Pennsylvania, it still is difficult to really document the total available resource and actual movement and quantity without implementing a very elaborate system of monitoring wells, observation points, and background water quality data.

Groundwater is stored in the voids, spaces and cracks between particles of soil, sand, gravel, rock or other materials. These cracks or space can include fractures, faults, bedding planes, solution channels (limestone formations), dissolution channels associated with more easily weathered material or other structural features such as bed planes or deformation in the bedrock due to folding. These materials form what is sometimes called the groundwater aquifer or reservoir. In most areas of the world, and specifically in Pennsylvania, water does not flow in and is not stored in large underground lakes or rivers. The only exception to this might be the dissolution channels and caverns associated with limestone formations, abandon mining sites, and mine shafts associated with underground mining operations.

The types of aquifers in Pennsylvania include: unconsolidated (sand and gravel deposits), sandstone, carbonate, and crystalline rock. The major water bearing aquifers in Pennsylvania are associated with sandstone and shale or sedimentary rock units.

Near surface the material can be divided into the unsaturated or saturated zone. Recently, the unsaturated zone has been termed to vadose zone to make it clear that the material may at times be saturated. Water in the vadose zone can move via saturated and unsaturated conditions. Under saturated conditions, the gravitational potential or gravity is the driving force, but under unsaturated conditions osmotic and matric forces are major influence.

The figure depicts the potential relationship between a recharge area and a discharge zone and the influence of an aquitard. Figure 7 shows that at some point in the landscape the aquifer is exposed near the surface. Recharge enters that aquifer, but in some cases an aquitard, i.e., a formation with a permeability that is at least 10 times, lower than the aquifer acts as a confining layer. This confining layer causes the water to be directed downslope and causes pressure to "build-up" in the confined aquifer. If there is a fracture or weakness in the confining layer, the water will move up from the deeper groundwater zone and discharge to the surface or shallow groundwater aquifer.

To understand how we can remove groundwater using wells, we must understand how groundwater moves. Some people attempt to associate the flow of water on the earth's surface with groundwater movement. Surface water flows in rivers or streams at velocities of 2-8 miles per hour. Pennsylvania's groundwater moves through the spaces between particles of a saturated material at rates between 0.1 foot per day to 3 feet per day. That translates into movement of 35 to 1,100 feet per year.

Groundwater moves only if sufficient pressure, or head, is available to force water through the spaces between porous aquifer materials. Rate of movement is determined by the hydraulic gradient, permeability, and porosity of the material. The hydraulic gradient, or slope of the water surface between two points in an aquifer, and the aquifer material determines how rapidly water moves from one location to another.

Groundwater moves from high water surface elevations (high pressure or head) to low water surface elevations (low pressure or head). In general, the water flows more rapidly where large differences exist in water surface elevations (steep hydraulic gradients), but this is not always the case. A large variation in the hydraulic gradient could also mean an lower permeability formation. Groundwater may move toward or away from streams or lakes, depending on the hydraulic gradient. As groundwater moves it may be removed by a pumping well, or it may be discharged to the earth's surface as a spring, a lake or stream. Groundwater supplies are recharged by precipitation or from rivers and lakes. Groundwater removed by wells or discharged by springs may have been stored for thousands of years, or may have entered the aquifer quite recently.

Under natural conditions, a balance exists between the volume of water entering an aquifer and the volume of water being discharged from an aquifer. Under natural conditions, the water is discharged from the aquifer through evapotranspiration, seepages, streamflow, and direct discharge to bays/oceans. With the development of water wells, the natural balance between recharge rates and discharge rates is disrupted and an artificial groundwater discharge zone is created when water is extracted from the ground. As long as the artificial discharge is balanced by enhanced recharge at the surface, such as the use of on-site well and septic systems, facilitated or induced stormwater recharge, or large volume treated effluent recharge systems, the water cycle stays near balanced. If these additional man-made or influence recharge systems are established, the result of over-pumping or over-withdrawing water from the aquifer could cause low baseflows in streams, warmer streams, less aquatic habitat, high storm or peak flows in streams because of more runoff, and potential failure of the groundwater system because of settling of an unconsolidated formation or induced contamination because of over-pumping.

A local geocacher informed me that this well has had possible contamination problems in the past due to nitrates and or E. coli. Due to this, I would advise not to drink from this well.

Come to the coordinates, enjoy the area, answer the questions and email to me for credit for the find.