Snow monitoring for sustainable development
One of the great challenges of the coming years, highlighted by the COP28 agreement in Dubai, is to speed up global efforts to mitigate climate change and cut greenhouse gas emissions. Sustainable development calls for greater and more efficient use of renewable energy, such as hydropower, wind and solar, which are becoming ever more central to the energy market.
Key figures
| Indicator | Value |
|---|---|
| Water supply coming from snowmelt | 60–70% (higher in high-mountain regions) |
| Snow produced by 1 cm of rain | from 2 cm (wet snow) to over 50 cm (dry, powdery snow) |
| Key variables for hydropower management | Snow Water Equivalent (SWE) and snow cover |
| Data sources for snow estimation | Satellite + weather models + in-situ measurements |
| Area covered by a CRNS measurement | radius of over 20 m |
| SWE measurement range | 0 – 10,000 mm water equivalent |
| CRNS sensor saturation limit | between 2,000 and 10,000 mm |
| Output unit | mm water equivalent (ready to use) |
| Sites in the ARPA Veneto SWE network | 25, Italy’s first regional CRNS-based network |
| CRNS measurement features | Contactless · continuous · fully autonomous |
Water resources
Snow cover is one of the most important resources in mountain regions, both economically and ecologically. Mountains act as natural reservoirs: they store snow in winter and release it in spring. Between 60% and 70% of water supply comes from snowmelt, with high-mountain regions at the top of this range. Knowing how much water snow will provide each year is essential for short- and long-term planning.
Hydropower
Hydropower generates electricity from river water, or water stored behind dams, that drives turbines. Output depends heavily on the natural variability of available water. For many power companies hydropower is a key part of the generation portfolio: it adds diversification, but also exposes them to natural resource variability.
Most generation takes place in the mountains, where potential energy is stored in the snow and ice layer. Managing plants, planning generation and storage, and assessing the impact on the energy market takes more than rainfall data. It also requires knowing how much water the snowpack holds: the Snow Water Equivalent (SWE).
Measuring SWE
In-situ measurements combined with satellite data and weather models improve estimates of snow cover and SWE, and reduce exposure to their natural variability. More accurate estimates help energy producers manage resources better, forecast hydropower output more reliably and generate more efficiently.
The challenge
Measuring the water in snow is not easy, because air temperature controls how much water a centimetre of snow holds: 1 cm of rain can produce anywhere from 2 cm of wet snow to over 50 cm of dry, powdery snow. This is why snow depth does not directly show how much water the snow contains, and why SWE is the most reliable way to estimate water reserves.
SWE supports several applications:
- Basin-scale water resource management
- Hydropower generation
- Avalanche risk monitoring
- Structural monitoring of large buildings (snow load)
- Snow and weather research
The innovation: CRNS sensors
The most innovative way to measure SWE is the cosmic-ray sensor (CRNS, Cosmic Ray Neutron Sensing). It measures ambient neutrons generated by cosmic rays and estimates SWE at the installation site without contact, continuously and fully autonomously.
How it works
- Reference detector: installed above the snowpack, it measures neutrons arriving from space before they interact with the snow.
- Ground detector: installed at ground level, slightly buried, while the ground is still free of snow. Once covered by snow, it counts the neutrons that have already passed through the snowpack.
- Measurement: the difference between the two detectors’ counts shows precisely how much water the snowpack contains.
SWE is delivered directly in mm water equivalent, covers a wide area (radius of over 20 m) and has a saturation limit between 2,000 and 10,000 mm.
Case study: the ARPA Veneto network
ARPAV, the regional environmental protection agency of Veneto, Italy, has installed CRNS sensors at 25 sites, creating Italy’s first regional SWE monitoring network based on this technology.
The Finapp impact
- Contactless measurement of water content in soil and snow
- More accurate hydropower forecasts and more efficient generation
- Precise, digital water management
- Less waste, lower energy costs, higher productivity