1. Faculty of Science and Engineering, Univ. of Waikato, Private Bag 3105, Hamilton 3240, New Zealand; and Hydrology Scientist, Lincoln Agritech, Ruakura Research Center, Ruakura Ln., Hamilton 3214, New Zealand (corresponding author).
2. Associate professor, Faculty of Science and Engineering, Univ. of Waikato, Private Bag 3105, Hamilton 3240, New Zealand.