Blue4Green Service

Water Monitoring

We monitor key indicators of surface water quality, including chlorophyll-a concentration, viewing depth, turbidity, algae growth, algal blooms and water temperature. This supports cities and municipalities in continuously observing, assessing and sustainably managing their water bodies.

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Overview

Water Body Monitoring

Water body monitoring provides satellite-based information on the condition of surface waters. It captures key water quality indicators such as chlorophyll-a concentration, water transparency, turbidity, algae growth, algal blooms and water temperature.

The results support municipalities and specialist authorities in detecting changes at an early stage, better assessing critical developments and planning water management measures more effectively.

Example

Service example

Water Monitoring preview
Indicators

What can be monitored?

Aquatic Plant Growth The Aquatic Plant Growth Indicator provides a five-level warning system for assessing the pressure exerted by in-water plant growth. It is based on multispectral satellite data (e.g., Sentinel-2 at 10 m resolution) whose reflectance patterns in the visible and near-infrared range are highly sensitive to dense aquatic vegetation. The result is large-area maps that give early warning of critical growth and thus support water-body management, maintenance measures and planning of water uses.
Algae Monitoring For this service, a water body must have a minimum area of 0.1 hectare and minimum dimensions of 30 meters in both width and length. This index provides a graded warning system, from no risk (1) to very high risk (4), for the occurrence of harmful cyanobacteria, commonly known as “blue-green algae.” By integrating satellite-based spectral signatures sensitive to phycocyanin pigments into a radiative transfer model enhanced by artificial intelligence, it delivers early warning of algal bloom formation. This enables timely management measures to protect ecosystems and human health.
Viewing Depth For this service, a water body must have a minimum area of 0.1 hectare and minimum dimensions of 30 meters in both width and length. Traditionally, viewing depth is measured using a black-and-white Secchi disk that is lowered into the water until it is no longer visible. With AI-optimized, satellite-based backscatter models, Secchi depth is derived as a measure of vertical water clarity or viewing depth. Viewing depth affects aquatic habitats and serves as a practical measure of eutrophication and water quality for ecosystem monitoring and management.
Turbidity For this service, a water body must have a minimum area of 0.1 hectare and minimum dimensions of 30 meters in both width and length. Turbidity, measured in Formazin Nephelometric Units (FNU), assesses the scattering of light by suspended matter such as sediments, organic particles, and microscopic organisms. Satellite-based algorithms for turbidity estimation, built on radiative transfer models, capture variations in surface reflectance to monitor sediment resuspension as well as the overall suspended load. High turbidity indicates elevated amounts of suspended matter, often associated with nutrient enrichment, and may pose risks to both aquatic life and human health.
Chlorophyll-a Concentration For this service, a water body must have a minimum area of 0.1 hectare and minimum dimensions of 30 meters in both width and length. Chlorophyll-a is the primary photosynthetic pigment in phytoplankton and serves as a direct indicator of green algal biomass. Measured in micrograms per liter, this parameter quantifies the abundance of microscopic plants and reflects nutrient loading, trophic status, and overall aquatic productivity as detected by satellite-based color sensors. High chlorophyll-a concentrations can pose a risk to human health.
Water Temperature For this service, a water body must have a minimum area of 1 hectare and minimum dimensions of 90 meters in both width and length. Water temperature provides essential information for monitoring aquatic ecosystems and managing water resources. It is recorded using satellite images in °C. The maps are available for clear-sky satellite overpasses and represent the temperature of the upper few millimeters of the water surface, typically measured around local noon.