What Is Soil Moisture Detection and Why Does it Matter?

If you want to learn the secrets of what’s going on just beneath the surface of the Earth, follow the soil moisture. Soil moisture detection can reveal where drinking water is being lost, where wastewater is polluting aquifers, or where structures might fail, to disastrous effect. With the right analysis, detecting soil moisture can even tell us whether the chemical or dielectric properties of the soil itself might degrade pipes or infrastructure placed within it.  

Effective moisture detection in soil, then, gives us data that can be used to preserve resources, protect the environment, and properly plan and secure critical infrastructure. 

What Is Soil Moisture Detection?

Soil moisture detection is the ability to locate and measure subsurface moisture content so we can learn what it has to tell us. There are several methodologies that can be used.

Traditional Methods

Until recently, the only available technologies for moisture detection within soil operated with a number of limitations. They allowed for only very localized and labor-intensive measures that involve field crews, ground penetration, and complex laboratory analysis.   

The laboratory moisture detection method, for example, uses ground crews to gather soil samples from the field; the samples are brought to a lab, weighed, oven dried, and weighed again. Another technique, the direct field test, deploys technicians to insert a device known as a time-domain reflectometry (TDR) meter into the soil. The device’s range is somewhat restricted, however, and both methods assess only the specific spots the field technicians have sampled. 

Satellite-Based Soil Moisture Detection

New advances using PolSAR on satellites and algorithmic analysis have changed this situation considerably. Satellite offers several new capabilities: 

• It examines vast areas quickly, thousands of square miles, without field crews, ground penetration, or laboratories.
• Detection by satellite is ongoing; changes in soil moisture over time can be highly revealing.
• It provides additional data on the characteristics of the moisture it detects; it can discern processed drinking water, for example.
• The efficiency of satellite-based detection makes it accessible to more governments and businesses that would benefit.

Where Can Moisture in Soil Be Detected? 

Anywhere soil moisture is detected, something valuable, often essential, can be learned.

For example, soil moisture in the vicinity of underground utility pipes can tell us where drinking water is leaking so that repairs can be made. In fact, for the water industry, soil moisture detection (by satellite) is far more efficient than traditional acoustic leak detection, which is done by ground crews on foot, literally ‘listening for leaks’ one at a time. Detecting soil moisture by satellite focuses on soil moisture over a broad area and can find dozens or hundreds of leaks at once.  

Other areas where detecting soil moisture can be critical are mining operations, including tailings dams that store toxic waste; dams and levees that store and manage water; beneath and near roads and rail lines and the hills on which they sit; and property developments with large, paved areas, such as airport runways and parking lots.

Why Does Detecting Moisture Matter? 

Detection and analysis of soil moisture can provide vital information with the potential to save lives, water, energy, money, crew resources, and the environment. 

In the example of leaking utility pipes, water, money, and energy (and the resulting carbon emissions) all must be expended again to replace what was lost. Leaking wastewater pipes can send toxins, pathogens, and other pollutants into the environment and water supply. 

Roads and railways depend on stable ground directly beneath them, and stable hillsides above and below; soil moisture detection shows where concentrations of soil moisture invite potential failure. Airport runways, where freight and passenger planes land every few minutes, can be compromised by soil moisture.

Detecting soil moisture near dams and levees can be used to anticipate and prevent breaches that would lead to catastrophic loss of life and property, and unlivable environmental degradation. Near mines, regular and reliable moisture detection can protect personnel, heavy equipment, and general operations.  

The Role of ASTERRA 

In all of these situations, moisture detection and analysis in soil can help detect any number of threats so that action can be taken to safeguard lives, property, business, and the environment.  

Please visit ASTERRA’s Solutions Page to learn about new advances in soil moisture detection using satellites and algorithmic analysis.