Geocache Description:
The water in an artesian well flows from an aquifer, which is a layer of very porous rock or sediment, usually sandstone, capable of holding and transmitting large quantities of water. The geologic conditions necessary for an artesian well are an inclined aquifer sandwiched between impervious rock layers above and below that trap water in it. Water enters the exposed edge of the aquifer at a high elevation and percolates downward through interconnected pore spaces. The water held in these spaces is under pressure because of the weight of water in the portion of the aquifer above it. If a well is drilled from the land surface through the overlying impervious layer into the aquifer, this pressure will cause the water to rise in the well. In areas where the slope of the aquifer is great enough, pressure will drive the water above ground level in a spectacular, permanent fountain. Artesian springs can occur in similar fashion where faults or cracks in the overlying impervious layer allow water to flow upward. Water from an artesian well or spring is usually cold and free of organic contaminants, making it desirable for drinking.
An artesian aquifer is a confined aquifer containing groundwater that will flow upward through a well (called an artesian well) without the need for pumping. Water may reach the ground surface if the natural pressure is high enough, in which case the well is called a flowing artesian well. The recharging of aquifers happens when the water table at its recharge zone is at a higher elevation than the head of the well.
What makes this artesian spring unique is it’s location. This spring is situated literally between two very different aquifer systems in the state of Indiana: the Silurian and Devonian Carbonates Aquifer System and the Ordovician - Maquoketa Group Aquifer System. These two aquifer systems have very different make-ups and by viewing the state map you can see how the two systems only overlap via a small branch off of the Ordovician -- Maquoketa Group Aquifer System into the vast Silurian and Devonian Carbonates Aquifer System. The artesian springs located in these two aquifer systems vary in depth of penetration and gallons per minute (gpm) output. This creates a unique dialogue and predictions as which aquifer system this well at the earthcache location is being fed by and can only be determined by taking the required measurements.
In general, ground-water hardness levels are higher in the northeast portion of Indiana in the West Fork White River basin relative to the southwest portion of the basin. The unconsolidated Tipton Till Plain Aquifer system and subsystem and the bedrock Silurian and Devonian Carbonates Aquifer system, all of which have high median hardness levels, cover a substantial part of the northeast portion of the basin. Calcium and magnesium concentrations in ground water are higher here as well Because calcium and magnesium are the major constituents responsible for hardness in water, the highest levels of these ions generally occur in ground water with high hardness levels. As expected, the unconsolidated Tipton Till Plain Aquifer system and subsystem and the bedrock Silurian and Devonian Carbonates Aquifer system have high median calcium and magnesium levels relative to most of the other aquifer systems in Indiana.
pH is responsible for controlling many chemical balances, including the ratio of nontoxic ammonium (NH4+) to toxic ammonia (NH3), and between the nitrite ion (N02-) and nitrous acid (HNO2). The term pH stands for the power of hydrogen and is a measure of the amount of hydrogen ions present in your water. The pH scale runs from 0.0 to 14.0. Values less than 7.0 are acidic, 7.0 is neutral, and values greater than 7.0 are basic. (Base/basic has formerly been referred to as alkalinity. Alkalinity is actually a measure of the buffering capacity of water.) Concentrations above 20 ppm impart a bitter taste to drinking water. Concentrations greater than 10 ppm may have a toxic effect (methemoglobinemia) on young infants.
The United States Environmental Protection Agency (USEPA) recommends a pH range between 6.5 and 8.5 in waters used for public supply.
Silurian and Devonian Carbonates Aquifer System:
In Randolph County, the younger Devonian age carbonates are not present and this aquifer system consists only of Silurian age carbonates. The Silurian and Devonian Carbonates Aquifer System outcrops/subcrops throughout much of Randolph County. The total thickness of this system in the county ranges from 0 to about 200 feet. In Randolph county predominately but in trace areas of Grant, Wabash and Miami counties, wells penetrating the Silurian and Devonian Carbonates Aquifer System have reported depths ranging from 35 to 380 feet, but are commonly 100 to 180 feet deep. The amount of rock penetrated in this system typically ranges from 20 to 70 feet, although many of the deeper wells also reach the upper portion of the underlying Maquoketa Group. Wells utilizing the Silurian and Devonian Carbonates Aquifer System are generally capable of meeting the needs of domestic users and some high-capacity users in this county. Domestic well yields commonly range from 10 to 35 gallons per minute (gpm). Static water levels typically range from 15 to 35 feet below the land surface. A few flowing wells have been reported for this bedrock aquifer system in the county. There are 8 registered significant ground-water withdrawal facilities (12 wells) utilizing the Silurian and Devonian Carbonates Aquifer System in Randolph County. Reported yields range from 80 to 600 gpm. High-capacity well depths range from approximately 40 to 400 feet below the land surface. Several of the high-capacity wells have contributions from both the Silurian and Devonian Carbonates Aquifer System and the underlying Maquoketa Group Aquifer System. This aquifer system is generally not very susceptible to surface contamination due to thick clay deposits over most of the county. However, solution features (caves) are described in a few well records suggesting minor karst development and there are localized areas, especially near the White River and the Mississinewa River, where the bedrock surface is shallow or exposed. These areas, therefore, are at moderate to high risk to contamination.
Ordovician -- Maquoketa Group Aquifer System:
The outcrop/subcrop area of this aquifer system is limited to the three main bedrock valleys in this county. The Maquoketa Group consists mostly of shales with interbedded limestone units. Although the Maquoketa Group Aquifer system is approximately 800 to 900 feet thick in the county, typically little more than the top 100 feet is used for water production. In Randolph County, some wells completed in the Maquoketa Group Aquifer System are open to and receive some water from the Silurian and Devonian Carbonates Aquifer System. However, wells completed solely in the Maquoketa Group Aquifer System are generally capable of meeting the needs of domestic users in this county. Wells exclusively utilizing the Maquoketa Group Aquifer System in Randolph County have reported depths ranging from 79 to 423 feet, but are commonly 120 to 300 feet deep. The amount of rock penetrated in this system typically ranges from 20 to 80 feet. Yields for domestic wells generally range from 10 to 30 gpm and static water levels are commonly 10 to 25 feet below the land surface. The Maquoketa Group Aquifer System is generally not very susceptible to contamination from the land surface because thick layers of clay-rich material overlie the bedrock.
TO LOG THIS EARTHCACHE:
1) Visit this location and take a picture of you and/ or your team and post it with your log (optional).
2) Use a testing strip and test the pH, iron, and calculate total hardness levels. (Test strips can be found at pet and hardware stores.) - AND - Estimate the Gallons Per Minute (GPM) flow rate by filling a one-gallon jug while timing how many seconds it takes to fill it; then divide 60 by the number of seconds it took to get your answer. To do this you will need a container of known volume and a watch with a second hand.
3) Which aquifer system do you believe, from your testing results, does this artesian well lie within?
4) Email me with the results of logging task #2 & #3 - Please do not include the answers in your log.
Please answer the questions correctly in order to be able to claim the smiley for this earthcache. I expect the required logging information for this earthcache to be sent to me within three days or the "Found It" log will be in jeopardy of deletion. Thanks!