Houston / Heustis Beach - Unconfined Aquifer EarthCache

Houston Beach - Unconfined Aquifer

Heustis Beach, Annapolis Valley

Some people call it Heustis, others call it Houston. No one seems to know which one, as it isn’t signposted. Heustis Beach is a lovely red rocky/sandy beach near the base of Blomidon. It’s a great place for a bonfire, or to swim in the Minas Basin.

At low tide take a walk along the shore and explore the sedimentary cliffs and various rock formations. Even at the highest tide, there is still a small beach area, and several tidal pools to explore. The tide goes out (or comes in) very quickly, so be aware!

An aquifer is a geologic formation, group of formations, or part of a formation that contains sufficient saturated, permeable material to yield significant quantities of water to wells and springs.  There are generally two kinds of aquifers: confined and unconfined.

Unconfined Aquifers

Where groundwater is in direct contact with the atmosphere through the open pore spaces of the overlying soil or rock, then the aquifer is said to be unconfined. The upper groundwater surface in an unconfined aquifer is called the water table. The depth to the water table varies according to factors such as the topography, geology, season and tidal effects, and the quantities of water being pumped from the aquifer.

Unconfined aquifers are usually recharged by rain or stream water infiltrating directly through the overlying soil. Typical examples of unconfined aquifers include many areas of coastal sands and alluvial deposits in river valleys.

In the diagram you will see the layers that make up both confined and unconfined aquifers. The top layer on the aquifer is permeable like sandstone and allows water to pass into the unconfined aquifer.  Nothing on top to seal it off from above it.

The layer between the unconfined and confined aquifer is denser like shale and does not allow water to pass into the confined.  It has a lower hydraulic conductivity. This means the measure of a rocks ability to conduct water. Shale does not conduct water easily like sandstone does, neither does basalt.

Here at the coordinates you can see an unconfined aquifer. If you examine the cliffs you can see different types of soils that make up the cliff.

To log this Earthcache please answer the following questions and send answers in a timely manner to my geocaching profile or email. Answers not received will result in deleted logs. Do not post your answers in your log.

Questions:

1. How high is the cliff?

2. What part of the cliff do you think is less porous ?

3.Describe the cliff and what types of soils and sands you see?

4. Why do you think the water leaked out at the top were the soil was sandy?

5. [REQUIRED] In accordance with the updated guidelines from Geocaching Headquarters published in June 2019, photos are now an acceptable logging requirement and WILL BE REQUIRED TO LOG THIS CACHE. Please provide a photo of yourself or a personal item here to prove you visited the site.