Algal early warning system under development
The NSW Office of Water has partnered with CSIRO to develop an early warning system for harmful algal blooms. The project will utilise satellite and other remote sensing technology to develop a system that aims to provide an inexpensive, timely and automated way of identifying and tracking potentially hazardous blue-green algal blooms in NSW lakes, rivers and reservoirs.
The system aims to provide real-time data on the locations and extent of algal blooms in NSW inland waters for the immediate use in the management of responses to the blooms, especially to ensure the health and safety of the public and other water users of water bodies impacted with algal blooms. It will enhance the monitoring and management abilities of the NSW Office of Water through the provision of more immediate data and a wider spatial coverage of major inland waters than is possible with current monitoring techniques.
The project team from the Office of Water and CSIRO includes experts in both remote sensing and in blue-green algae. The team has access to the advanced technology required, including satellite and other near surface remote sensing instruments, databases, and the algorithms needed to convert the raw remote sensed data into reliable estimates of the amount of blue-green algae present in a water body and the hazard it poses to water users.
The remote sensing data will be backed up by additional data collected by other instruments that detect blue-green algae and the optical properties of the water in-situ, as well as a laboratory verification program. Some initial investigations have been undertaken by the Office of Water testing the applicability of a hand-held remote sensing device (a WISP-3) in monitoring blue-green algal blooms in small urban lakes in eastern Sydney over the past two summers.
The project will take place in five stages over a three year period. The first two stages will involve developing the means for rapid bloom identification using both near surface sensing instruments and satellite sensing.
The aims of these two stages is to develop a rapid and simple approach to identify the greening of a water body associated with algal blooms, based on Australian recreational water use guidelines and its "traffic light" systems of Green, Amber and Red alerts, which indicate an increasing severity of blooms.
The third stage will involve the development of a software framework that will allow an automated rapid turnaround of satellite data into the 'green', 'amber' and 'red' algal reports.
The fourth stage will develop, validate and test the robustness of algorithms for the quantitative estimation of blue-green algae specific pigments and chlorophyll across the range of different water quality conditions typical of NSW water bodies.
Finally, the fifth stage aims to achieve accurate concentration measurements of chlorophyll-a and of other water quality attributes such as total suspended sediments and coloured dissolved organic matter that may confound the measurements of blue-green algae, as well as to investigate how to discriminate blue-green algal blooms from blooms of other less harmful algae.
The graphs below shows the results for phytoplankton and suspended sediments:
Subsurface reflectance measured by WISP-3 spectro-radiometer at Centennial Park lake.
|Colour composite image of lake showing presence of sediments and subsurface vegetation.|
|Image in spectral wavelength (0.45-0.52 micrometres) showing signals reflected from water.|
|Image in spectral wavelength (0.77-0.90 micrometres) showing absorption in water. No signal reflected back to the sensor.|