Field and modelling investigations of fresh-water plume behaviour in response to infrequent high-precipitation events, Sydney Estuary, Australia

Abstract

words: 321 Text words: 7,921 References: 1,258

Emerging contaminants (pharmaceuticals, personal care products, a food additive and pesticides) in waters of Sydney estuary, Australia

“…During dry weather conditions fresh water discharge is low (<0.1 m 3 /s) (Birch and Rochford, 2010) and salinity is homogeneous throughout the estuary (Hatje et al, 2001). Both low fresh-water discharge and tidal turbulence contribute to well-mixed estuarine conditions with salinity ranging from 27 at the headwaters to 35 at the mouth in the absence of precipitation (Lee et al, 2011. Flushing rates vary from <1 day at the mouth to 225 days at the landward end of the estuary (Das et al, 2000).…”

Spatial distribution of heavy metal contaminations in Yowie Bay sediments and their environmental impacts

“…Main discharge points carry materials from catchment areas, which are pushed into the bays. The sediment pathway into the bay is in the form of a jet since water velocity decreases gradually when entering the bay, causing deposition of coarse materials close to discharge points and then fine particles further into the bay [19,20]. Local waves, generated by wind, become more influential in the shallow waters close to the discharge points, leading to resuspension and transport of fine particles into deeper sites, where the current and waves become less active and cannot disturb the bottom sediments.…”

Potential effects of storm-water run-off on assemblages of mobile invertebrates

“…Hence, all control locations were (1) at a minimum distance of 300 m from any visible storm-water drain as properties of water quality (i.e. salinity and turbidity) at this minimum distance showed different temporal patterns of changes following rainfall compared to those in locations with storm-water drains (Roberts et al 2007); and (2) surrounded by low density residential/park land areas, which a have a lower impervious surface area than highly urbanised areas (Lee et al 2011). …”

“…Volumes of run-off at each potentially impacted site were estimated using the impervious surface area of the relative subcatchment and the average daily rainfall intensity (Lee et al 2011 standardised to a 100 ml volume because these 2 variables are related to the volume of the holdfast (Smith et al 1996, Anderson et al 2005. This standardisation may be problematic under speciose conditions, but it was used as a conservative way of accounting for variation in volumes.…”

“…The outfalls of these locations drain predomi- nantly highly urbanised, residential catchments. The run-off volumes discharged at each of the potentially impacted locations during the rainfall events prior to our samplings were estimated (Table 1) using the impervious surface area of the relative subcatchment and the average daily rainfall intensity (Lee et al 2011;www.bom.gov.au/climate/data). Shark Bay (C1) was chosen as a control because contamination by run-off appears to be minimal here as there are no swimming restrictions following rainfall events (Anon 2010).…”