Hydrogeology EarthCache

Hydrogeology is the term used for studies between Hydro Engineers and Geologists. The term is used as the study of ground waters in the soil and rock of the earths crust. Groundwater can be classified into several categories which include aquifers, water tables, springs and seeps. All of these contribute to the creation of wetlands, streams and lakes. With this earthcache we will be looking at an aquifer and its place in hydrogeology.

There are two main types of aquifers, confined and unconfined. The easiest way to describe the two is to say that confined is water underground and is contained in rock. Unconfined is for the most part is known as the water table and is surface water. It is on the top of the rock crust though it may be under the soil. The aquifer type that we will be working with is confined.

An aquifer is the layer or layers of permeable rock. Rock like sandstone and limestone absorbs water from an inlet path at high elevation. 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. By doing this it has created an Artesian well.

The co-ords above will be taking you to an Artesian Well. The name Artesian Well comes from the former province Artois in France. It was here where the Carthusian monks began to drill and tap these wells starting in 1126. These wells have been the fresh water supply for entire towns. Because the water has been flowing through the rock it has been filtered and is fresh and safe as drinking water. It is also pressurized as it flows up from the ground almost defying gravity. This pressure varies depending on the elevation of the origin of the water flow, also the elevation of where the well has been tapped.

So now you know how this well came to be, now enjoy a nice cool fresh drink as you get ready to complete this cache. You will need to complete the following to be able to log this cache.

You will need to bring a couple of tools with you to do this cache. You will need a gallon jug - a cleaned-out milk jug will work well and it will be a good container to take a fresh gallon of water home with you. You will also need a thermometer. Bring a way to time the flow of water, this will be in seconds. Lastly you will need your camera.

1. Fill your gallon jug using the spout on the side of the well. As you are filling the jug you will also be timing how long it takes to fill it. By timing the fill of this gallon you can calculate the pressure of this well. Using the time of filling 1 gallon e-mail me the gallons per hour this well is pumping. Do not post it in your log!

2. Hold your thermometer under the flow from the well for 30 seconds. Report your tempture in your log so that we all can watch the consistencies through out the year.

3. Take and post a picture of you or your team at this well.