Welcome to my Earthcache! An Earthcache is a special type of geocache where there is no container to find - instead you are looking for a unique geological feature of the area and need to answer questions, as well as posting a picture, in order to claim the find. This EarthCache explores the powerful effects of water erosion in a natural setting altered by human infrastructure. You'll observe how the water discharged from a drainage pipe has significantly shaped the landscape around it, leading to several distinct geomorphological features.
EARTHCACHE REQUIREMENTS
As with all of my ECs, I am not looking for PhD thesis level responses, but I am hoping that you take some time to enjoy the area and learn something new. Please include a list of all cachers with your answer, if answering for more than one caching name. There is no need to send individual answers.
To claim a 'find' for this Earthcache you must answer the following questions and send your answers in a message or email to the owner using the link at the top of the page. You can log your find with a photo at GZ. Send your answers to the tasks. I will be in contact if there is a problem, no need to wait for a response as long as the required photo is included in your log.
Please be cautious when exploring this area. Watch for unstable banks, especially near the pipe and pool. This area can be very muddy and slippery especially after/during rainfall.
Questions to Answer:
1. Estimate the depth of the pool directly in front of the pipe. Why do you think it's so much deeper than the rest of the creek?
2. Describe the color of the water. What might be contributing to this discoloration?
3. What role does the small floodplain (to the east of the drain) play in the creek’s health and stability?
4. What signs of erosion can you see on the opposite bank (to the west of the drain)? How do you think this has changed over time?
5.Mandatory: Include a photograph of yourself, your GPS, a signature item, thumbs up, etc with the location in the background. You do not need to show your face in the photo, but your photo must be unique to you. Each log must upload a photo (even if it is a group photo).
Geology Lesson:
Erosion is the process by which soil and rock are removed from the Earth’s surface by wind or water flow, and then transported and deposited in other locations. In natural streams, erosion occurs gradually, but when water is redirected or concentrated—such as through a drainage pipe—the process can intensify dramatically. At GZ, you will find one such pool - these show an excellent example of how human interference can change natural erosion.
- The Deep Scour Pool (Directly Below the Pipe)
You’ll notice the pool directly in front of the drainage pipe is significantly deeper than other parts of the creek. This is caused by the energy of fast-moving water exiting the pipe, especially during heavy rain or snowmelt events. The force of the water erodes the streambed, creating a scour hole—a classic feature seen where high-energy water meets softer sediments. But why is the water discolored? The murky and/or greenish tint is likely due to sediment being suspended in the water column, disturbed by erosion, and possibly nutrient loading from upstream runoff. Nutrients like phosphorus and nitrogen from fertilizers or decomposing organic material can lead to algae blooms and discoloration of natural water sources, such as this creek.
- Downstream: Shallower Waters
As you move away from the scour pool, the creek becomes noticeably shallower. This is because the water’s velocity drops as it spreads out and loses its energy. Suspended sediments begin to settle out, and erosion is much less intense. This contrast highlights how human-made infrastructure changes natural flow dynamics.
- Small Floodplain (To the Right of the Pipe)
On the right side of the scour pool, a small floodplain has developed. This relatively flat area collects overflow during high water events. Sediments carried by the water are deposited here, and over time, this area may build up in elevation. Floodplains serve as natural buffers, helping to slow water and reduce erosion during floods.
- Eroding Bank (Opposite the Pipe)
The streambank on the opposite side of the pipe is undercut and collapsing in places. This erosion is being driven by the redirected flow from the pipe hitting the opposite bank at high velocity. Over time, this process causes the bank to slough off, contributing more sediment to the water and altering the stream's shape.
Human Impact Summary: The drainage pipe carries runoff from a road or developed area. By concentrating water flow into a single, forceful stream, it disrupts the balance of erosion and deposition. Instead of gentle meanders and slow sediment transport, we see dramatic scouring, undercutting, and displacement of natural features.
This cache was placed by a PROUD Platinum Earthcache Master.
