Monitoring Water Quality from Space

Algal Blooms in Lake Erie, around Monroe, acquired by Sentinel-2 on 3rd August 2017. Data Courtesy of ESA/Copernicus.

Two projects using Earth Observation (EO) data to monitor water quality caught our eye recently. As we’re in process of developing two water quality products for our own online portal, we’re interested in what everyone else is doing!

At the end of January UNESCO’s International Hydrological Programme launched a tool to monitor global water quality. The International Initiative on Water Quality (IIWQ) World Water Quality Portal, built by EOMAP, provides:

  • turbidity and sedimentation distribution
  • chlorophyll-a concentration
  • Harmful Algal Blooms indicator
  • organic absorption
  • surface temperature

Based on optical data from Landsat and Sentinel-2 it can provide global surface water mosaics at 90 m spatial resolution, alongside 30 m resolution for seven pilot river basins.  The portal was launched in Paris at the “Water Quality Monitoring using Earth Observation and Satellite-based Information” meeting and was accompanied by an exhibition on “Water Quality from the Space – Mesmerizing Images of Earth Observation”.

The tool, which can be found here, focuses on providing colour visualizations of the data alongside data legends to help make it as easy as possible to use. It is hoped that this will help inform and educate policy makers, water professionals and the wider public about the value of using satellite data from monitoring water resources.

A second interesting project, albeit on a smaller scale, was announced last week which is going to use Sentinel-2 imagery to monitor water quality in Scottish Lochs. Dr Claire Neil, from the University of Stirling, is leading the project and will be working with Scottish Environment Protection Agency. It will use reflectance measures to estimate the chlorophyll-a concentrations to help identify algal blooms and other contaminants in the waters. The project will offer an alternative approach to the current water quality monitoring, which uses sampling close to the water’s edge.

An interesting feature of the project, particularly for us, is the intention to focus on developing this work into an operational capability for SEPA to enable them to improve their approach to assessing water quality.

This transition from a ‘good idea’ into an operational product that will be used, and therefore purchased, by end users is what all EO companies are looking for and we’re not different. Our Pixalytics Portal which we discussed a couple of weeks ago is one of the ways we are trying to move in that direction. We have two water quality monitoring products on it:

  • Open Ocean Water Quality product extracts time-series data from a variety of 4 km resolution satellite datasets from NASA, giving an overview what is happening in the water without the need to download a lot of data.
  • Planning for Coastal Airborne Lidar Surveys product provides an assessment of the penetration depth of a Lidar laser beam, from an airborne survey system, within coastal waters based on the turbidity of the water. This ensures that companies who plan overflights can have confidence in how far their Lidar will see.

We’re just at the starting point in productizing the services we offer, and so it is always good to see how others are approaching the similar problem!

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