Located in the City of Bunbury, the Leschenault Inlet was once connected to the Leschenault Estuary and was known as one waterbody, the Leschenault Inlet Estuary. At that time, the Leschenault Inlet was the mouth of the Preston River. However, it is now a separate waterbody to the Estuary and is a semi-confined waterbody/lagoon that has significant recreational and social importance to the City of Bunbury. Water levels in the inlet are controlled by a set of flood gates.
Biological and physical values
White mangrove: Avicennia marina
- Small remnant stands of White mangrove (Avicennia marina) are located within the Leschenault Inlet. This vegetation is a relic of an earlier tropical period and is the only population of mangroves south of Shark Bay (EPA 1993). Given that it is the southern-most occurrence of this species, its presence in the estuary and inlet is scientifically important in the region and is a feature of national significance (Semeniuk & Withers 2000).
Bottlenose dolphins (Tursiop sp.)
- Bottlenose dolphins are known to spend time in the Leschenault Estuary, inlet and lower section of the Collie and Preston rivers. The dolphin deaths in 2009 and more recently in December 2010 are a cause for concern. Maintaining the health of the estuary and its associated waterways is important to ensure a healthy dolphin population.
- The estuary and associated wetlands are of considerable importance for waterbirds, with more than 62 species recorded (CALM 1998).
Current Condition and Trends
Water quality and algae
- Heavy metals, metalloids and nutrients found in sediment likely derived from urban drainage.
- Nutrient accumulation in sediments above average levels; 2005 snapshot survey showing elevated levels (Semeniuk V and C
- Occasional blooms of low toxicity with harmless diatoms Skeletonema, Chaetoceros and Asterionella sp. Presence of harmless
dinoflagellates Katodinium, Oxyrrhis and Peridinium sp.
- Prolific growth of macroalgae in the summer months.
- High tidal exchange prevents the accumulation of elevated soluble nutrient concentrations within the water column.
Land use pressure
- The inlet is surrounded by intensive urban land use, housing and industrial developments. Thus the inlet is highly modified with a high proportion being artificially retained; remnant foreshore is only associated with the mangrove population on the northern foreshore.
Leschenault Inlet and Climate Change
SWCC Strategic Priority
The Leschenault Inlet is identified within SWCC’s NRM Strategy as a second order priority asset under the Aquatic Biodiversity theme.
- Hugues-dit-Ciles, J, Kelsey, P, Marillier, B, Robb, M, Forbes, V & McKenna, M 2012, Leschenault estuary water quality improvement plan, Department of Water, Western Australia.
Header and thumbnail images supplied by City of Bunbury.