The Waters Borehole

October 16, 2026.

We have dug a 60cm hole in our backyard through the rubble to install soil and humidity probes. I have been yammering about doing this for 16 years. It's such a small thing, but I am jazzed.

It is live, you can find it in the sidebar.

This is a proof-of-concept project for my Sonoran Desert Soil Observatory which I had included with my PhD proposal.  I'm aware of SCAN. They don't take soil temperatures in places I care about, namely slopes in rocky habitat within ravines and talus. Their data is collected near aquifers in the flats which correlates with rangeland.

https://www.nrcs.usda.gov/resources/data-and-reports/soil-climate-analysis-network

Climate change isn't just about air temperature and rainfall, as one sees on the news and mass media; plants ultimately rely upon soil thermal and moisture conditions for germination and growth. Change occurs on a scale the human eye cannot follow. We are too busy eating our rice crispies to realize the volume of the birds chirping in the background keeps dropping.

Seeds from species that can't germinate translates into entire ecosystem displacement. Eventually the adult plants die and vanish. Small animals are completely reliant upon vegetative cover and soil conditions. The plants provide the basis of the food web, shade, and percolate water into the soil during rain. Rain otherwise rolls off the surface and develops into flashfloods which further washes away any developing soils. When it dries, the soil develops hardpan, or caliche' which further exacerbates moisture retention and reduces subsequent soil formation. Plants are unable to directly penetrate this layer and use spreading roots for stability, thus growing low to the ground. This has a host of ecological effects that affect all levels of the community. It's complicated, which makes it interesting, and frustrating because people just want to know whether they are going to be ok or not and go back to fidgeting doing something.

You can read about some of the soil conditions here. I am not a soil scientist. I look at soil from a habitat perspective.

https://en.wikipedia.org/wiki/Desert_pavement

https://en.wikipedia.org/wiki/Caliche

If the project can be set up in a reliable, incredibly low-cost fashion, I will shop it as a small project proposal to the Desert Botanical Garden and to other ecological monitoring locations in the Southwest. Soil conditions are key to understanding environmental change. Notice I used the word environmental.

Currently, the soil temperature is 71 F and 25% relative humidity at 50 cm depth in the backyard. The biological significance of these factoids don't matter out of context, other than it seems like a nice condition to be a snail in. If you ask me, it still seems too dry, and I'd be waiting in my shell until moisture conditions pick up. We had at least two hurricane remnants go through in September and early October, dumping at least 5" of rain, and at that depth it's still warm to the touch and somewhat dry.  Hm. It took all of two days of warm dry air to crack mud, which shuts off dew production. Think about that.

The Machines

The equipment to make this happen is now reliable, inexpensive, easy to maintain, and data will be automagically uploaded to weather aggregators. EcoWitt soil monitoring products are available on Amazon. I'm not a fanboy, it's just the gear that does the job and I hope it does it well.

ECOWITT WN34BL Digital Thermometer with LCD Display

ECOWITT WH51L Soil Moisture Sensor with LCD Display

ECOWITT GW1200BU Wi-Fi Gateway Weather Station, with Built-in Temperature, Humidity, and Barometric Sensors

ECOWITT Wittboy Pro Weather Station HP2564

I may install a camera in the borehole and one pointing at the rockpile. To be determined.

For Science

If possible, We will set it up so the critters can enter hidey holes and take up residence. I am hoping to be able to see where they are estivating in relation to soil temperature and humidity. There may be a web cam or two in there. It's not hard science; this is good old fashioned ecological empirical data gathering and directly witnessing nature to see what the critters do in relation to measured weather conditions.  Perhaps this may lead to more concrete questions, such as what are the environmental tipping points for estivation to be induced; what biochemical changes occur within the snail? Can we leverage that physiology for other applications? That is the basis of science, after all.

A somewhat silly example follows. Why does a pointy thing hurt? Why do they do a better job killing woolly mammoths than a club? That's where science begins. A simple observation, verified through experience. That lesson leads to further questions and answers. Before you know it, you have materials science and a deep understanding of the physics of sharpness. Science is not arcane witchcraft. Wake up, sheeple!

I have strategically placed this soil weather station next to a big pile of riprap in the NW corner of the back yard. It will be partially shaded by grapes and a to-be-planted Arizona willow. There will be no watering at the soil weather station.  Soil and atmospheric weather data will be uploaded to Weather Underground. The GPS coordinates of the site are

https://maps.app.goo.gl/hiPMCGS86nJuJK2F7

I have a solid years worth of subsurface weather data from the mountains adjacent to the neighborhood. It's unpublished as yet.

Maybe there will be cameras someday, pointing at the riprap pile and inside the borehole.

I intend to have probes at 30cm and at the soil surface within the rock layer itself. That's a total of 6 probes and with any luck, we can see how the data plot against rainfall events and the changing atmospheric conditions, alongside snail detections whether in the yard or afield. The climate around Phoenix is essentially monotypic.

Soils in the desert region are generally shallow and I feel confident that once the probes are 30 cm below ground they will give a solid read. Any deeper and soil temperature and humidity remain stable. Digging deeper into the soil past the caliche' layer doesn't make sense, either, since that is a bedrock type moisture barrier.

Soil Temperature Measurement

Soil temperature ISO is here. I assume it is in use. I suppose I should look into that.

https://www.iso.org/standard/80550.html

Record Skip. They want me to pay money for that 9 page international standard in pdf? What madness is this.

The USDA standard for soil depth and root penetration gives us the guidance we need.  SCAN has 200 stations, it's just a disappointment there is only 1 in all of Arizona, and is on rangeland in SE.

My Project Hard Expenditures

Ecowitt Soil RH probes: 4 x $40 = $160

Ecowitt Temperature probes: 4 x $40 = $160

Ecowitt Weather Gateway: $34

Ecowitt Weather Station: $300

Personal time involved: $0 priceless

Subscriptions to weather services: $0 thank you

Labor: $50 paid in pizza and praise

Grand Total: $800 with shipping and batteries not included

This does not include tools and costs associated with acquiring landscaping materials, nor account for any site preparation. You may need to afford a dumptruck of rubble and provide for labor and tools to get it to your site, which will cost ~$1000. I'm not doing anything fancy. It is a good old fashioned pile of rocks.