Seaham Weir Monitoring 2025-2026

The Seaham Weir Refurbishment and Modification Project enhanced one of the most important assets in the Grahamstown Dam supply system, which provides around 40% of Hunter Water’s drinking water. Located on the lower Williams River, the project delivered new low‑flow weir gates to improve operational efficiency and a contemporary vertical‑slot fishway designed with significant input from AFPS. Since commissioning, AFPS monitoring over approximately 20 sampling days has recorded just under 400,000 fish representing 18 species, ranging in size from 8 mm (Australian bass) to 1200 mm (longfin eels). This extensive dataset confirms that a wide range of species are successfully using the fishway for both upstream and downstream migration, demonstrating strong ecological performance and improved river connectivity.