In the late 1980s, growing concern over the impact of irrigated agriculture on the surface and ground waters of NSW, lead the Department of Land and Water Conservation (DLWC), to conduct a water quality monitoring program in the Macintyre, Gwydir, Namoi and Macquarie valleys of NSW. This program commenced in 1991/92 and has been jointly funded by the DLWC and the water users of these valleys, whose on going concern, contributions and support are gratefully acknowledged.