Algonquin Water Works Earthcache
The Village of Algonquin was established here in 1896 because this spring provided "the best drinking water to be had in Illinois."
The water gushing out of this spring arrived as rain falling on the hillside. Over time, the water sinks through the soil until it hits a rock layer and gets trapped there.
The spring is fed by water trapped between these impervious layers of rock higher up the hillside, across Pioneer Road. The rain soaked into the ground and formed a water table. But there the water became trapped between layers of impervious rock. The rock is water tight, so excess water built up higher than this outlet source.
Even though it gushes out with great force, new rains continuously recharge the water field, so it never runs dry. Residents of the area have been using this spring for drinking and cooking since 1896.
Cisterns to hold excess water were built and you can still see them north of the deck. A pumphouse was built to distribute the water around the village to local residents homes, and remained in use until 1996.
The spring is no longer used for residential drinking water, but it still runs strong, at the same pressure of 80 psi, all day long, all year long, 24/7.
Analogy: A small example how this works:
Imagine you have a plastic bag full of small pebbles and rocks, and there is a tiny pinhole in the bottom of the bag. You put the bag under a faucet and fill it with water and the water gushes out the small hole. Even if you turn the faucet off, the water still drains from the hole in the bag for some time.
The pebbles are the inside of the hill (the hill is not empty but has loose porous rock inside). The plastic bag is the impervious rock layer. The hole is the spring outlet. The faucet going on and off is the rainfall charging the water table. Water still pours out the hole even when the faucet is off because the hillside holds lots of water above the spring.
Questions you must answer to score the smiley for this cache:
Q1: At what pressure, in pounds per square inch, does the water gush out of the ground here? Read about the history on the sign on the rail.
Q2: Estimate the height of the hillside north of Pioneer Road. How much higher than the spring is the top of the hill along Cary Road? You can use your GPS if it shows elevation. You can also go up on Cary Road and look down toward this area. How far is the up and down distance?
Q3: How does the water breach the surface? For example: bubble up through the soil, flow out between two rocks, shoot up in the air from a pipe? (none of those is the correct answer - describe it in your own words.)
Feel free to read about the Algonquin history and Pioneer Park on the plaque on the viewing deck. Explore the remains of the rock wall, but be careful. Between boulders, holes in the earth, and thistles, take care.
You might even find another regular cache right nearby.....
This cache approved by the Village of Algonquin Geocache Registration #228485. Please be respectful of the wetlands.
FTF Congrats to j3yoda & athrillofthehunt