Terrain characteristics influencing aquifer salinisation of the Glenelg-Hopkins CMA region, using GIS

Salinisation of aquifers is an issue of great concern in the Glenelg-Hopkins region. The GlenelgHopkins region is located in south-west Victoria, south of the Great Dividing Range and covers 2.6 million hectares. The area receives an annual average rainfall of 500-910 mm and experiences a Mediterranean climate, with hot, dry summers and cold wet winters and has varied geology and soil types. Terrain characteristics, such as soil type, geology, depth-to-water table, land use and topography have been integrated into a Geographic Information System (GIS). A geostatistical approach, including the use of multiple linear regression is used to analyse the spatial variability of the relationships between aquifer salinity and terrain characteristics across the entire region. Results from this study should greatly improve knowledge of aquifer salinisation across the region. It is expected that this work will enable managers to determine the most appropriate mitigating measures for each specific area affected.

Sudden drawdown and drainage of a horizontal aquifer

Drainage of a saturated horizontal aquifer following a sudden drawdown is reanalyzed using the Boussinesq equation. The effect of the finite length of the aquifer is considered in detail. An analytical approximation based on a superposition principle yields a very good estimate of the outflow when compared to accurate numerical solutions. An illustration of the new analytical approach to analyze basin-scale field data is used to demonstrate possible field applications of the new solution.

A biogeographically mixed late Guadalupian (late Middle Permian) brachiopod fauna from an exotic limestone block at Xiukang in Lhaze county, Tibet

A total of 17 brachiopod species belonging to 15 genera are recorded from a limestone block of about 3×4 km2 in the Indus–Tsangbo suture zone at Xiukang in Lhaze County of Tibet. The brachiopod fauna generally indicates a Late Guadalupian age (late Wordian–Capitanian, late Middle Permian) based on its association with the Timorites-bearing ammonoid fauna and the presence of the brachiopod Urushtenoidea crenulata. Palaeobiogeographically, the fauna exhibits transitional/mixed characters between the warm-water Cathaysian and cold to temperate Gondwanan faunas and may have developed on a carbonate build-up or seamount on the oceanic crust.

Controlled field studies on soil aquifer treatment in a constructed coastal sandfill

A controlled artificial recharge experiment was conducted to investigate the effect of soil aquifer treatment during percolation of secondary and tertiary (ultrafiltered) treated wastewater through the shallow vadoze zone of a newly constructed coastal sandfill. The sandfill is a reclaimed land constructed from marine sand dredged from the seabed. To obtain 1-D flow, a stainless steel column was driven to a depth of 2.5 m, penetrating the phreatic surface. Wastewater was percolated through the column under fully-saturated and unsaturated conditions. Infiltration rates, dissolved organic carbon (DOC) and ultra-violet absorption (UVA) were monitored. The wastewaters were recharged at similar infiltration rates of approximately 5.5 m/day and 3.5 m/day under fully-saturated and unsaturated conditions, respectively. In both cases, clogging occurred 40 days after the start of recharge, under saturated conditions. For secondary treated wastewater, DOC concentration (mg/l) reduced by 28% and 13% under unsaturated and saturated conditions, respectively. The corresponding UVA reduction was 19.4% and 14.1%. Similar reductions in DOC were observed for the tertiary treated wastewater; however, the reduction in UVA was higher; 28% and 22% under unsaturated and saturated conditions, respectively. On an mass removal (mg/m(2) DOC) basis, DOC reduction appeared to be more significant under unsaturated conditions. This is attributed to the presence of interstitial oxygen.

DOC and UVA attenuation with soil aquifer treatment in the saturated zone of an artificial coastal sandfill

Results from a direct recharge experiment conducted in the field to investigate DOC and UVA(254) attenuation rates during the direct injection of UF treated wastewater into a artificial coastal sandfill are presented in this paper. Approximately 500 m(3) of ultra-filtered wastewater was injected into the saturated zone, over a period of 9 days. The movement of the plume was tracked over 80 days, during which time samples were obtained from multilevel samplers installed in transects across the drift axis of the plume. An analysis of fluorescein in the samples obtained during the drift of the UF plume showed that DOC and UVA were attenuated beyond rates predicted by conservative mixing, by up to a maximum of 45%. A degradation coefficient of 0.0175 day(-1) was found to be applicable for DOC degradation. After a drift period of 80 days, DOC and UVA reduced to approximately 4.5 mg/l and 0.100 cm(-1), respectively, from initial values of 8.06 mg/l and 0.199 cm(-1).

Middle permian brachiopods from central Peninsular Malaysia - faunal affinities between Malaysia and west Cambodia

A moderately diverse Permian brachiopod fauna is described from a new rock unit, the Bera Formation, in the Bera District, central Pahang, Peninsular Malaysia. The fauna consists of 19 taxa, including 14 genera and 17 (both identified and unidentified) typically Tethyan species. The fauna appears to be correlative on the basis of brachiopods with the Neoschwagerina-Yabeina fusulinid Zones in Indochina and South China. In particular, it has strong linkage to Member C (Yabeina beds) of the Sisophon Limestone, west Cambodia. This is indicated by three of the Bera species — Urushtenoidea chaoi (Ching), Spyridiophora gubleri Termier and Termier, and Transennatia termierorum sp. nov., being shared with the Cambodian fauna. A possible early Capitanian (Middle Permian) age is proposed for the Bera brachiopod fauna.

Drying front in a sloping aquifier: nonlinear effects

The profiles for the water table height h(x, t) in a shallow sloping aquifer are reexamined with a solution of the nonlinear Boussinesq equation. We demonstrate that the previous anomaly first reported by Brutsaert [1994] that the point at which the water table h first becomes zero at x = L at time t = t c remains fixed at this point for all times t > t c is actually a result of the linearization of the Boussinesq equation and not, as previously suggested [ Brutsaert, 1994 ; Verhoest and Troch, 2000 ], a result of the Dupuit assumption. Rather, by examination of the nonlinear Boussinesq equation the drying front, i.e., the point x f at which h is zero for times t ≥ t c , actually recedes downslope as physically expected. This points out that the linear Boussinesq equation should be used carefully when a zero depth is obtained as the concept of an “average” depth loses meaning at that time.

Prevalence of psychological distress, anxiety and depression in rural communities in Australia

Objective: To describe the prevalence of psychological distress, depression and anxiety in three Australian rural settings and to identify the levels of risk by gender and age.

Design and setting: Three cross-sectional surveys in the Greater Green Triangle area covering the south-east of South Australia (Limestone Coast), and south-west (Corangamite Shire) and north-west (Wimmera) of Victoria.

Participants: A total of 1563 people, aged 25–74 years, randomly selected from the electoral roll.

Main outcome measures: Psychological distress assessed by the Kessler 10, and anxiety and depression assessed by the Hospital Anxiety and Depression Scale.

Results: The prevalence of psychological distress was 31% for both men and women with two-thirds reporting moderate and one-third high levels of psychological distress. The prevalence of depression and anxiety was approximately 10%. The highest rate of psychological distress, anxiety and depression occurred in the 45–54 years age group. There were no consistent gender or area differences in the prevalence of psychological distress, depression or anxiety.

Conclusions: A third of the rural population reported psychological distress, with the highest prevalence observed in middle-aged men and women. Thus, health professionals should attend not only to physical health, but also to mental health status in this age group. It is also important to target prevention strategies at the 20% who reported moderate levels of psychological distress in order to prevent the development of more serious conditions.

Detection and habitat use of the rufous bristlebird (Dasyornis broadbenti) in coastal heathland, in south-western Victoria, Australia

The Rufous Bristlebird (Dasyornis broadbenti) is a sedentary, ground-dwelling passerine of southern Australia, which is listed as nationally vulnerable, and as near-threatened (lower risk) in Victoria. The species inhabits a variety of vegetation, including shrub thickets in coastal gullies to heathlands on limestone cliffs. This study aimed to assess the size, distribution and habitat use of a population of the subspecies D. b.  broadbenti at Portland in south-western Victoria. Monthly surveys (2002–03) were conducted on foot for 1 h after official sunrise and 1 h before official sunset, and presence of Bristlebirds recorded using vocalisations and sightings. Observations outside of the survey times were also recorded to estimate the size of territories and core area of occupancy. To quantify habitat preferences, vegetation composition and structure were measured in areas where Bristlebirds were present, as well as surrounding areas where they were not detected. The population in the survey areas was estimated at between 70 and 86 individuals in the 170-ha survey area. The estimated size of territories of eight selected pairs of Bristlebirds ranged from 0.5 to 3 ha, with core areas of occupancy ranging from 0.2 to 0.6 ha. During the nesting season (August November) Bristlebirds were detected at greater frequencies in the core area of occupancy within each territory. Significant associations were found between the presence of Bristlebirds and floristic associations dominated by the native environmental weeds Acacia sophorae and Leptospermum laevigatum. Bristlebird presence was significantly positively correlated with increasing vegetation density in the mid-canopy level (80–120 cm) indicating that vegetation structure is a key factor in habitat use.