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The headwaters of the Buayanyup River occur in state forest where four tributaries flow through native vegetation before flowing through agricultural land. The lower section has been straightened into drainage channels, before flowing into Geographe Bay at Abbey.
The Buayanyup River catchment has a diversity of land uses, including beef and dairy farming, vineyards and horticulture. Native vegetation and timber plantations occur in the south eastern corner of the catchment, and the growing townsite of Vasse occurs in the lower catchment. Nutrients, particularly nitrogen, enter the river from dairy and beef grazing, dairy sheds and horticulture.
Native species, including the Western Minnow, Western Pygmy Perch , Nightfish, Blue-spot Goby, Gilgie, Smooth Marron, Freshwater Shrimp, Koonac and Long neck turtle, have all been found in the river.
Five Mile Brook is a small waterway in the north of the catchment. It flows seasonally to Geographe Bay near Minninup Beach. Five Mile Brook is surrounded by agriculture, particular beef farming, with some urban areas at the south of Dalyellup Estate.
Five Mile Brook has poor water quality. This is due to sandy soil, which does not retain nutrients well, and extensive grazing agriculture in the catchment.
Water sampling by local school groups has found evidence of macroinvertebrates, tadpoles and turtles.
The Gynudup Brook catchment consists of two main tributaries; Tren Creek and Gynudup Brook. The headwaters of Gynudup Brook are in State Forest, which then flow across agricultural land before connecting with the Capel River west of Bussell highway.
The hydrology of the catchment has been extensively modified, containing many artificial drains to alleviate water logging in winter months. Most of the catchment is cleared for agriculture, and the waterways suffer from poor water quality.
Despite being significantly altered, the waterways in the Gynudup catchment provide refuge for several native species including freshwater shrimp, Western Minnow, Blue Spot Goby, Nightfish, Gilgie and the Long-necked Turtle.
The Capel River is the largest and only perennial river in the Geographe Bay Catchment, receiving groundwater discharge from the Leederville aquifer year-round. Several foreshore reserves of conservation value are situated on the Capel River, including Ironstone Gully Falls.
Land use of the upper Capel River catchment is predominately native vegetation and beef farming. The lower catchment is dominated by beef and dairy farming with pockets of native vegetation and horticulture. The townsites of Capel and Peppermint Grove Beach also occur in the catchment.
The Capel River has relatively good water quality. Carters Freshwater, Smooth Marron, Gilgie, Freshwater Cobbler, Nightfish, Western Pygmy Perch, Western Minnow and Pouched Lamprey can be found in the catchment.
The Ludlow River is the only major waterway to discharge to the Wonnerup Estuary. Its upper catchment lies in the Whicher National Park, after which it flows across the coastal plain through grazing and dairy farmland, horticulture and turf farms.
These land uses contribute nutrients to the river, which suffers from poor water quality. There has been, however, a decreasing trend in nutrient concentrations in the river since 2011.
The Ludlow River retains native aquatic fauna including the Gilgie, Freshwater Shrimp, Nightfish, Western Minnow, Western Pygmy Perch and the Blue Spot Goby.
The Abba River begins in the Millbrook State Forest, flowing seasonally across the Swan Coastal Plain, through the Ludlow Tuart Forest and eventually into the Vasse Estuary. Landuse in the Abba sub-catchment is predominantly beef and dairy farming, with smaller amounts of sheep farming, vineyards and horticulture.
Ecological surveys of the river have found a diversity of native fish and freshwater crayfish including the Western Minnow, Nightfish, Blue-spot Goby, Western Pygmy Perch, Gilgie and Freshwater Shrimp.
The Abba River is categorised as an ‘intervention’ sub-catchment for water quality, where it meets phosphorus targets, but not nitrogen. Fertiliser for pasture is the largest source of nutrients to the river. We work with landholders and our partners to reduce these nutrients by fencing waterways, fertiliser management and dairy effluent upgrades.
The Lower Sabina River flows into the Vasse Estuary. It is separated from its upper catchment, which is diverted into the Vasse Diversion Drain.
The Lower Sabina catchment is small, mostly cleared, with agricultural landuses dominated by dairy and beef farming. The river contributes a significant amount of nutrients to the Vasse-Wonnerup Wetlands.
The river supports Gilgie, Southwest Glass Shrimp, Nightfish, Western Minnow, Western Pygmy Perch and the Blue Spot Goby.
The Lower Vasse River flows through the centre of Busselton, extending from the Vasse Diversion Drain at its headwaters, to the Vasse Delta Wetlands at the downstream boundary. The river receives winter flow from the Vasse Diversion Drain through a 900 mm culvert.
The lower catchment is dominated by urban, residential development, while the upper catchment is primarily beef grazing.
The Vasse River suffers from poor water quality and in summer months experiences regular algal blooms. Despite these water quality problems, the Lower Vasse River retains significant ecological values, including a high diversity of fish and native crayfish.
The Vasse Diversion Drain receives water from approximately 60% of the Sabina River catchment and 90% of the Vasse River catchment, di