The Water Insight Spectrometer (WISP) is an easy to operate handheld device, developed by the remote sensing experts of Water Insight BV in The Netherlands, providing real time surface water quality information. By taking an optical measurement, the WISP (within a minute) derives water quality indicators such as:
- the concentrations of chlorophyll-a,
- concentration of phycocyanine,
- CDOM (colored dissolved organic matter),
- water transparency (Secchi) and
- suspended matter,
without the need for further laboratory analysis. Compared to laboratory measurements the WISP is fast, flexible and cost effective, and an indispensable tool in modern water management.
The WISP means immediate and rich availability of information, ready for interpretation and action.
Applications of the WISP
Due to its speed, flexibility and instantaneous availability of data, usage of the WISP and its web portal enables day-to-day decision support systems for water management organizations where algal blooms affect:
- drinking water safety,
- swimming water safety,
- ecological status of lakes, ditches and coastal areas.
Concentrations of chlorophyll, phycocyanine, and suspended matter, transparency and reflectance are presented in the display on-the-spot. The WISP creates the possibility to immediately observe and analyze the effects of certain water system management decisions.
The WISP is using powerful algorithms developed by interpreting satellite data above large surface water areas. These satellite data however cannot be used reliably for scanning surface water quality near-shore and for inland smaller water bodies. Therefore the WISP has been developed, providing sufficiently detailed quantity and quality data regarding organic matter, suspended solids, etc. It is now possible to monitor surface water bodies with high accuracies, irrespective of the weather conditions and/or distortions in satellite data availability.
The data generated by the WISP can be read directly from a LED display at the device, are near real time and are automatically introduced into WISP-web, a website which is automatically processing the observations and storing the data into the required format for reporting.
The WISP is increasingly being used by prestigious water management organizations worldwide, and is expected to become the market standard for instant water quality information.
The data generated by the WISP are generated per nanometer in the visible part of the spectrum. The database system can communicate with most other databases or viewers (e.g. FEWS and LIZARD). As such continuity of previously recorded historical data sets is guaranteed.
The raw data sets that are generated by the WISP remain available for use by future algorithms, as a data mine for water quality information (e.g. on currently not deemed relevant algae or contaminations) for future use.
The accuracies and ranges of our measurements are equal to or even better than those derived from laboratory measurements.
The WISP contains three radiometers measuring reflectance (‘the color’) of the water. From this optical signal, the WISP directly derives the concentrations of water quality indicators such as chlorophyll and suspended matter, without the need for laboratory analysis.
The WISP relies on a simple principle: the color of the water contains the information on what is present in the water. E.g. phytoplankton blooms usually turn the color of the water green. More accurate than the human eye, the color of the water can be seen by satellites. Using in situ radiometers this becomes possible with even more spectral resolution. Our physical model enables the conversion of color into reliable concentrations.
Our method works everywhere in the world; at most the algorithms need to be adapted to the local properties, which will then result in reliable and reproducible results.
The online WISP-web system allows users to analyze the obtained data in detail, and secures safe storage. In the future, WISP-web will also include features to aggregate higher level information and pre-format results for reporting.