Murray River Lock 4 at Berri in South Australia

Murray River Lock 4 at Berri in South Australia

Murray River Lock 4 is located 10 minutes drive south of Berri in South Australia, is one of the sixteen locks and weirs built along the Murray to regulate water levels and aid navigation. Construction began in 1928 and finished in 1929, forming part of a major inter-state effort to manage Australia’s most important river system.

At that time, unpredictable water levels often disrupted river transport and irrigation. The lock system aimed to secure reliable navigation for paddle steamers and supply stable water for expanding agriculture. Engineers designed Lock 4 to control the river flow between Loxton and Berri, providing consistent depth for vessels and irrigation channels.

The lock’s completion marked a milestone in South Australia’s river development. It became an essential component of a project that united three states—South Australia, Victoria, and New South Wales—under the 1917 River Murray Waters Agreement. This initiative transformed the Murray from a variable natural river into a managed waterway serving farms, towns, and industries along its course.

Engineering and Design

Lock 4’s design reflects the robust engineering of the early twentieth century. The lock chamber measures 61 metres long and 9 metres wide, built from reinforced concrete and stone facing. It includes a weir structure that maintains a stable upstream pool level while allowing excess water to pass through gates.

A manually operated control system originally managed water flow. Over time, upgrades modernised the mechanisms, improving safety and efficiency. Yet, the original structure remains largely intact, showcasing the durability of early Australian river engineering.

Adjacent to the lock is the weir pool, a stretch of calm water extending several kilometres upstream toward Loxton. This area supports irrigation for vineyards and orchards that define the Riverland region. Moreover, the steady water level benefits aquatic life, providing habitat for native fish and bird species.