Random Time Sampling

Random Time Sampling is an innovative data collection method which has potential for adaptation and use by geographers. Individual pocket-sized programmable beepers were used in a pilot study of the uses of time by older households and older people's attitudes to different activities. Random beeps were used to prompt individuals living in eleven Melbourne suburbs to record time use data in diaries over a period of a week. The method proved extremely effective and reliable, and many participants reporting that they enjoyed the exercise.     

The Impact of Urbanisation on Water Quality in the Lane Cove River,Sydney New South Wales: a Comparison of Urban and Non-Urban Catchments

The Lane Cove River drains an established urbanised catchment and is impacted by urban runoff, point sources of pollution from sewer overflows and leachate from a refuse tip. The Sydney Water Board conducted a three year water quality monitoring programme assessing the impacts of pollution. The findings are presented and the impact of urbanisation evaluated by comparing water quality in urban and non-urban catchments. Water quality in a near-pristine control creek was consistently better than the urban catchment in all weather conditions. During wet weather, water quality in urban creeks deteriorated significantly, although the control creek generally remained in a near-pristine condition. Poor water quality in urbanised reaches of the catchment has degraded the aquatic ecosystem, encouraged and sustained weed infestation of the riparian environment and restricted recreational use of the river.     

Morphological Impacts and Implications of a Trial Release on the Wingecarribee River,New South Wales

A trial, monitored release on the Wingecarribee River over 27 days had a peak discharge below the Wingecarribee Dam of 1090 ML/d, which had a flow duration of 0.95 per cent. Morphological impacts on 29 km of channel below the dam included bank erosion, concentrated neck overflow, bed degradation and channel widening at recent cutoffs, sedimentation in weir pools and overbank flow, particularly at discharges greater than 800 ML/d. Prolonged operational releases at bankfull discharge (400–800 ML/d) will have the greatest morphologic impacts and should be avoided. Pulses which dissipate stream power over a broad, well-vegetated floodplain should be incorporated in the operational release policy, provided such pulses are phased to facilitate channel and vegetation recovery.     

Human and Natural Controls on the Accumulation,Acidification and Drainage of Pyritic Sediments: Pearl River Delta,China and Coastal New South Wales

There is increasing concern about environmental impacts of acidic drainage from acid sulphate soils on Holocene estuarine flood plains. Acidity derives from oxidation of iron pyrite in the sediments. Natural factors determine concentrations and distributions of pyrite accumulations, but human activities have reduced pyrite accumulation in the Pearl River Delta with land use practices increasing terrestrial sediment discharge. Large freshwater discharges and management techniques have enabled sustainable use of these soils. High concentrations of pyrite occur in many estuarine flood plains of Australia because of relatively greater marine inputs. Drainage of these soils enhances pyrite oxidation and estuarine acidification, which is associated with fish-kills. For sustainable development, the problems of acid sulphate soil drainage must be recognised and overcome.     

Estuarine Acidification: Impacts on Aquatic Biota of Draining Acid Sulphate Soils

Acid sulphate soils form when iron pyrite oxidises to sulphuric acid on atmospheric exposure, lowering soil pH below 4. In the Richmond River estuary, northern New South Wales, flood mitigation, drainage works and floodplain excavations have augmented acid sulphate soil formation by increasing pyrite availability for oxidation. These engineering works have facilitated the transport of acidified water and have impeded recovery from tributary acidification. The increased frequency and duration of acidification are associated with elevated concentrations of inorganic monomeric aluminium and dissolved iron, and major iron hydroxide precipitation, with deleterious effects on exposed aquatic biota and habitat. Fish kills and an outbreak of epizootic ulcerative syndrome (EUS) have been recorded from acidified sites in the estuary.