The Intersecting Streams located in north-western NSW forms part of the Darling River drainage system that crosses the New South Wales-Queensland Border. The rivers drain a remote low relief landscape and are largely ephemeral in nature. They provide for irrigation, stock, domestic, mining, town water and recreation. Annual rainfall averages less than 500mm with the western areas being classed as semi-arid.

Water quality monitoring began in the early 1990’s to better understand the base-line characteristics of these remote semi-arid systems. We have collected over 20 years of data from six rivers spanning multiple wetting and drying periods, enabling a unique long-term understanding of the water quality characteristics of these ephemeral rivers during different climatic conditions.

Electrical conductivity of the Warrego and Paroo Rivers are notably lower than the other Intersecting Streams, with medians of 89ms/cm and 133ms/cm respectively. Turbidity levels are highly variable throughout and have the potential to be very turbid, with most sites giving median turbidity levels over 300NTU and the Paroo and Warrego Rivers having medians over 600NTU. The Paroo River has extremely fine sediments that remain in suspension indefinitely regardless of environmental conditions, with the lowest Total Suspended Solids result being 64mg/L.

The Paroo and Warrego were the only rivers in the Murray-Darling Basin Sustainable Rivers Audit (2012) to be given scores that suggests their overall condition is close to natural. Examination of this water quality record will provide valuable information about these unique semi-arid river systems for future water management within the Murray-Darling Basin and across Australia.