How Wells & Aquifers Actually Work

He is named Grady Hillhouse because he likes grades, hills, and houses. The ultimate civil engineer

This man has consistently made me more interested in dirt and concrete

As a hydrologist and geotechnical engineer, I can't tell you how much I appreciate your videos. Even after my education and experience (in the field and office), your videos always seem to give me a better understanding of... well, just about any topic. Thank you!

You consistently have the coolest visual aids, but this was one that really helped me understand this better. I was also thinking while watching this that this is such an efficient way to spread this information. A teacher may have to build and run this diagram every year, but you're educating millions for the amount of water used for a shower and some acrylic. Well done.

In the Netherlands coastal regions they found that the dunes would hold a lot of clean water. They started pumping this water up around the 1870s, but ran into problems by the 1940s: salt from the sea would infiltrate the aquifer and make the water undrinkable. Now they pump fresh water into the dunes from rivers and pump it out on the other side. This allows for water storage and at the same time the sand in the aquifer cleans the water. This works so well that they don't have to add any chlorine and still have safe drinking water.

Something else to know: "Fossil" aquifers. There are many aquifers that are so deep and geologically isolated that they practically don't recharge at all. Once the water is removed it can take millennia to return. These aquifers are essentially a non-renewable resource (like oil) and unfortunately many places have become reliant on them, setting themselves up for catastrophic water shortages when the aquifers run dry.

Me at 3 AM and 2.1 M people learning how wells work for no apparent reason

Your “garage models” are fantastic they make understanding the topic so much easier. You’re a great fabricator as well as an engineer.

Well if there was any doubt about who had the more professional engineering channel, it was settled by me laughing at 8:10.

The use of dye tablets to show the flow of water was a great idea! This worked much better than I thought it would, it's striking how much they "draw" the path taken instead of just dissolving in the surrounding area.

I enjoyed your video on groundwater - these are concepts that are often difficult to grasp, and you have done a remarkable job of explaining them. I know from experience, because I was a professor of Hydrogeology (yes, there is such a thing) before I retired, teaching at the 3rd y level and up. What I love most about hydrogeology is that it draws from all sciences: chemistry (aqueous, organic, and even isotope), physics (Darcy's law in particular); statistics (when dealing with heterogeneous aquifers); Mathematics (as the universal language); numerical methods and computer programming. It can be a fairly simple applied science, as you have so well illustrated; but it can also be quite a bit more complicated for example in describing muti-fluid flow in heterogeneous aquifers (think for example of gasoline spills in layered aquifers). One small addition I would like to make to your great presentation is that, in most practical applications, water movement is actually driven by a gradient of Hydraulic Potential in the direction of flow, which is made up of a pressure component and a gravitational component; not just pressure. If the aquifer is uniform and has no preferred direction of flow (or is "homogeneous and isotropic") the only time that flow is driven by a pressure gradient is in special conditions such as when flow is horizontal (no gravitational component), otherwise it is driven by the Hydraulic gradient (made up of both components). So, to properly and quantitatively describe flow in your (very nice) aquifer model you would need to use the Hydraulic Potential (often expressed in units of length of water or "Head"), particularly as you get nearer a pumping well. Sorry for the rambling (gosh I love this stuff)!

As someone who is having long-term residential well issues, this video has been amazing at explaining just how these systems work in a way I hadn't previously understood properly.

Greetings from a Hydrogeologist in Australia! Loved your model, if only all aquifers were that simple 😉

"Correcting the misconceptions that abound around water below the ground" I appreciate how this sentenced is crafted.

Wow. "#1 channel on the internet about dirt". The hubris of man truly knows no bounds.

As someone who drills water wells and installs complete systems, this was pretty fun to watch.

It’s remarkable how good your videos are. Thanks for making them.

"Even now, the rules that govern groundwater in many places are still WELL behind our collective knowledge of hydrogeology." ..... nice! One of the many nerdy reasons why I love this channel. :D

You are a good instructor. Thank you for staying on track and not straying off the subject.

Can’t wait to hear what you have to say about fracking. Another great video, and I love the small scale models as always. I’m sure a ton of extra work went into making those models, adding the dye, taking the dye out, putting in clean water, etc. That effort isn’t missed or wasted!