DRBNats, 8 MAY 2026
Mike Griffiths presented an overview of the Peel–Yalgorup wetlands, tracing their transformation from early colonisation to modern environmental management. His talk was supported by his photographs and historical references, including those from Keith Bradby OAM’s 1997 book Peel-Harvey: The Decline and Rescue of an Ecosystem.
Historically, the wetlands stretching toward Harvey were extensive, slow-flowing swamp systems of major ecological importance. These environments were largely non-navigable, bordered by tuart and banksia woodlands. Fish species such as mulloway were abundant, and the wetlands were a vast, rich and valuable resource to Indigenous communities. They used fish traps and harvested freshwater crayfish at Korijekup Creek as part of their seasonal food practices.
European settlement began around 1829 and brought significant environmental change. Early settlers, including Thomas Peel, attempted to establish agriculture in these wet and unpredictable landscapes. Their efforts were challenged by flooding, poor access, and limited understanding of wetland ecosystems. Despite these difficulties, land clearing began, and settlers introduced various “remedies” to improve land productivity, facing “nine months of swamps” across much of the area.
By the late 19th and early 20th centuries, large-scale modifications were undertaken to convert wetlands into agricultural land. Logging and clearing intensified in the Wheatbelt and around Harvey in the 1890s, followed by the construction of drainage systems to remove excess water. By the 1920s, wider, more efficient drains enabled increased agricultural expansion. However, these interventions disrupted natural water flows, causing some areas to become too dry in summer and contributing to sediment build-up in estuaries.
Agricultural development accelerated throughout the early to mid-20th century. Soil testing and the widespread use of superphosphate fertilisers improved productivity, supporting dairy farming and cropping. Infrastructure such as dams and drainage networks further transformed the landscape. While these changes increased agricultural output, they also caused long-term environmental damage.
From the mid-20th century onward, environmental impacts became increasingly evident. Nutrient runoff, particularly phosphorus, led to declining water quality and algal blooms, including cyanobacteria such as Nodularia. The original Peeltown had developed into Mandurah, a popular holiday destination, yet the waterways had become saline and emitted unpleasant odours. By the 1970s, these issues had become a political concern, reflecting the cumulative effects of altered hydrology and intensive land use.
In recent decades, efforts have focused on environmental management and restoration. Concerns about biodiversity loss, invasive species, and salinity have led to mitigation strategies such as improved fertiliser practices, the use of red clay treatments, upgrades to Pinjarra wastewater discharge, and the construction of the Dawesville Cut to improve water flow. Monitoring programs and protected areas, including Yalgorup National Park, now play an essential role in conserving the remaining wetlands.
This history highlights important lessons. Wetlands are highly sensitive systems requiring careful management, and poorly planned land use can have lasting impacts. Effective solutions depend on combining local knowledge, sustainable agricultural practices, and coordinated catchment management. Local environmental groups and organisations, such as 5 Rivers NRM (formerly Peel-Harvey Catchment Council), are maintaining and increasing community awareness of the wetland system, highlighting its complexity and international significance. Protecting biodiversity and maintaining water quality are now recognised as critical to ensuring the long-term health of the Peel–Yalgorup wetlands.
Arlene Quinn