Herbert water quality monitoring project: 2011–2013 results

Herbert Water Quality Monitoring Program (HWQMP) is a three-year monitoring program that began in July of 2011. The HWQMP is an industry initiative that aims to determine the relative contribution of land use to the delivery of reef pollutant loads to the receiving waters of the Great Barrier Reef (GBR). Over the past two years, the program has undertaken the monitoring of sediment, nutrient and pesticide concentrations in surface waters collected from various sub-catchments. Surface waters were collected from 16 sites which cover the main land uses within the Herbert Catchment – rainforest, cropping, urban, dairy, mining and grazing in the upper catchment; and sugarcane and urban in the lower catchment. While the HWQMP will continue for the third and final year of monitoring, this paper will present the data for the first two years and compare the difference between years with regard to rainfall and river discharge profiles at the gauging sites investigated. Further, particle size analysis has been undertaken in an attempt to identify the sources contributing the majority of the sediment end of catchment loads within this system. Initial results demonstrate that pesticides atrazine and diuron regularly exceed the national guidelines for freshwater ecosystem protection, with a significant introduction of diuron to the waters of the Herbert River following the passing of the rain depression associated with ex-tropical cyclone Oswald through the catchment. Upon completion of the three year monitoring program the data generated will assist in informing the community, NRM mangers and various industry stakeholders that use and rely on the land in this region of potential issues they may face. Further, the data generated will then provide 'land use specific' water quality data to be used in the validation of catchment models for the Paddock to Reef Integrated Monitoring, Modelling and Reporting Program (Paddock to Reef Program)