A new joint initiative from international water and environment experts DHI and Auckland Council has recently gone online to the public. The Auckland Bathing Water Forecast (ABWF) is designed to provide forecasts of bathing suitability for central Auckland for up to three days. Recent high test results from some of the monitored beaches indicate that the innovative system is needed. The popular Takapuna North Shore beach was earlier this year closed to the public due to poor water quality.
Dr Jarrod Walker, a senior marine scientist from Auckland Council and one of the main drivers behind the initiative, says the enterprise is beneficial for planning. “With the model, you can jump online on a Friday afternoon and see that the beach is safe now and over the weekend.”
The ABWF uses data gathered data from a variety of sources including Met Service, Auckland Council and the National Centre for Environmental Prediction. Tidal and wind-driven currents in the Waitemata Harbour are simulated in a three-dimensional hydrodynamic model developed by DHI.
Key overflows in the vicinity of central city bathing beaches, which are a significant source of pollutants to the harbour, have been identified and a relationship between rainfall and overflows with associated enterococci has been calculated.
Concerned water users clicking through to the site will see a series of flags indicating trigger levels for swimmer safety. The flags, which are in accordance with Ministry for Environment recreational guidelines, pop up with a window displaying the water quality.
Although the model does not account for pollutants associated with dry weather overflows or re-suspension of bacteria-laden sediments, it does give residents a significant indication of whether or not to go for that swim they were planning after wet-weather events.
Photo courtesy of Auckland Council.
This article was first published in the May 2015 issue of NZ Local Government Magazine.