MATERIALS NEEDED: ziploc, tape, soda straw (you may do the experiment once you return home if you wish – see logging requirements for details).
Logging Requirements: Send the answers to #1 - #3 to me through my geocaching profile. DO NOT post the answers to any logging requirements on this site.
- 1.List the name “GC2AKYJ Angwin's Hope Springs Eternal Earthcache” in the first line of your email. Also, list the number of people in your group.
- 2.Do the following experiment to discover how artesian pressure works. Fill a plastic baggie with water, put a straw in through the opening, tape the opening around the straw closed, then squeeze the baggie. DESCRIBE what happens. Vary pressure in an attempt to simulate various seasons and rain/moisture conditions. DESCRIBE.
- 3.Describe the rocks visible on the surface. Using a hand magnifier, attempt to discover their porousness. In other words, do you see any “sponge like” nature, even on a small scale? If not, then how do you think the aquifer gets filled (read description).
- 4. Post a picture of yourself and your GPS with your log that shows you and the spring DO NOT show any of the pertinent information panels in your picture or y OR tell me how many rocks are used in the cemented construction of the spring outlet.
I will only respond if you have incomplete logging requirements. Go ahead and log your cache
Getting There: The road between Angwin and Pope Valley is steep and winding. There is a waypoint I have listed where there is parking (for ONE car) on the uphill side about 100 ft. from the earthcache. PLEASE do not try to access this cache when traveling from Pope Valley – get it on your return trip!
Artesian wells were named after the former province of Artois in France, where many artesian wells have historically been drilled by Carthusian monks since 1126. The technique was also known much earlier in Syria and Egypt, although whether the monks of Artois learned of it from outside sources, or discovered it independently, is unknown.
Geology:
An artesian aquifer is a confined aquifer containing groundwater that will flow upwards out of a well without the need for pumping. An aquifer provides the water for an artesian well. An aquifer is a layer of soft or porous rock, that absorbs water from an inlet path. Typically, porous stone is crushed between impermeable rocks or clay. This creates places, sometimes hundreds+ feet above “sea level” that contain reservoirs/aquifers of water. Of course, this arrangement of defined “containers” keeps the pressure high, so when the water finds a hole, it exits, sometimes even when it needs to defy gravity to do so.
In the Sonoma Volcanics region, we have a basaltic ridge of rocks of igneous origin (part of a volcanic field, even though there seem to have been NO true volcanos in the region, the closest true volcano being Mt. Konocti). These rocks are porous, largely because the igneous evolution of the rocks contained a significant number of air bubbles (Pervious Strata). Lower in the ridge is a harder, non-porous basement rocks (impervious Strata) that do not have the aeration that is present in the “tuffed” basaltics above. Because the top layers of rock are porous, water from rain filters into the rocks and sits in these underground “reservoirs”. Of course, the problem is that what goes in must come out, sooner or later, especially if MORE keeps getting added....the pressure builds and water must come out – which it does here through a pipe cemented into a cliff. Some may wonder whether this has been a spring, even before the pipe!
