An ongoing program of water quality sampling was initiated by OEH in 2007 to provide data on chlorophyll a and turbidity for reporting on the condition of estuaries in NSW. Sampling is conducted annually over the summer period in a three year rolling program between CMA regions. Seven fixed estuaries are sampled each year together with a minimum of 27 randomly selected from three estuary types and three levels of catchment disturbance. Each estuary is sampled on six occasions over the summer sampling period and in up to three longitudinal zones. Chlorophyll a samples are sent for laboratory analysis and turbidity is measured using a field probe. Other parameters are measured to support interpretation and research.