Carpentaria Coast bore information mostly comes from upper aquifers, and from two primary regions: the Roper River in the Northern Territory and the Mitchell–Coleman river system in Queensland. More than 100 bores had timeseries data, with some 70 having sufficient data to support a 5-year trend analysis. Of these, around 40 showed a rising trend, 20 were stable, and the remainder showed a declining trend. Water level status was mostly average, with an equal minor mix of below average and above average levels.
Groundwater data for the Lake Eyre Basin come mostly from the Diamantina–Georgina rivers system, with a small number of sites in the Cooper Creek – Bulloo system to the east of the basin. Reasonable coverage of upper, middle and lower aquifers is available. Sixty sites supported decile analyses of levels, with just over half having below average values and one-third being average. Of the 48 sites with sufficient data for timeseries trends, 27 were declining, and the remainder were equally distributed between stable and rising trends. This counters some of the information available from the mid-term review for stage 3 of the Great Artesian Basin Sustainability Initiative (Sinclair Knight Merz 2013), which reported anecdotal evidence of increasing bore pressure and increasing flow from bore springs. Similarly, a recent water resource assessment for the Great Artesian Basin (Smerdon et al. 2012) indicated that, when considering the 20 years up until 2010, there was clear evidence of recovery of groundwater levels arising from bore-capping and water-piping activities.
More than half of the bore timeseries available from the national information system are for bores in the Murray–Darling Basin, with bores in all 28 of the Basin’s river regions. More than 7000 of the 10,400 sites are for upper aquifers, and the remainder are evenly split between middle and lower aquifers. More than 5000 bores have sufficient data to support decile analyses of water level, with most showing average levels, and the remainder fairly evenly distributed between below average (1202 bores) and above average (1231 bores). Groundwater trends were mostly (3429 out of 5518) rising, with slightly more than 1500 bores stable and nearly 600 declining.
The North East Coast division is well represented, with groundwater data for most areas south of Cairns. Data are available for nearly 5000 sites, with 3500 of these reporting on the upper aquifers and 3600 reporting on water level status. Of the 5000 sites, 2000 had above average water levels, and most of the rest were in the average range. Clusters of below average values are evident near Atherton and west of Toowoomba, and clusters of above average levels occur near Ayr, near Bowen, near Mackay, inland of Bundaberg, west of Toowoomba and at North Stradbroke Island. Groundwater trends are largely rising (50 per cent) and stable (37 per cent), with clusters of rising trends around Toowoomba and inland of Bundaberg.
No groundwater observations are available in the national database for the North Western Plateau. Only a small set of bore data is available for the Pilbara–Gascoyne division, all but 3 of which are in the Greenough River region, to the south. Most bores have average to above average levels, with trends mostly stable.
Nearly 1000 bores have data available across the South Australian Gulf division, the bulk of which are located towards the coast, south of the Lake Torrens – Mambray Coast river region. Nearly 750 bores have sufficient data to support decile analysis, with around 43 per cent of bores above average and 38 per cent in the average range. Trends are available for 800 bores, and are mostly rising (322 bores) or stable (349 bores). A minority are declining.
Although 300 bores are recorded in the national database for the South East Coast (New South Wales) division, fewer than 25 have data suitable for analysis; these are dominated by average groundwater level status and stable trends.
The South East Coast (Victoria) division has been the focus of considerable groundwater investigation, being a trial area for development of a standardised groundwater information model and database (Sinclair Knight Merz 2009). More recently, it has been an area for investigation of a multi-annual timeseries analysis approach to assess the effects of pumping and climate drivers on groundwater levels (Shapoori et al. 2015). Data from more than 1500 bores are available, mostly for the upper aquifers, spread from the Mitchell–Thomson river region in the east to the Millicent Coast at the Victoria – South Australia border. Average range groundwater levels exist for 46 per cent of bores, and the remainder are evenly distributed between above average and below average levels. Trends are reported for 1259 bores, with the majority being stable.
Bores within the South West Coast division are located predominantly in the coastal and near-coastal regions, mostly between Busselton and Joondalup–Yanchep. Levels are in the average (54 per cent) or below average ranges (38 per cent), with trends mostly being stable or declining. Very few bores show a rising trend.
There are 165 bores reported in the South Western Plateau division, all of which are in the Gairdner River region, and most of which are east of Penong, thereby limiting the relevance of the bore information for the whole division. Of the 95 bores supporting decile analysis of levels, nearly two-thirds have groundwater levels in the average range. Trends are reported for 130 sites, with most being stable during the past 5 years.
The Tanami–Timor Sea Coast division has data available for 263 bores, most of which are in the Adelaide, Daly, Finniss and Victoria River – Wiso river regions. Data are available for a good range of lower, middle and upper aquifers, with a significant majority of bores showing levels in the average range. Trends are less evenly distributed, with 53 per cent of bores having a rising trend, 27 per cent stable and 40 per cent declining. A small cluster of rising trends is evident west of Katherine.
Six bores from Tasmania have timeseries data available in the national database, although around 2000 bores are included in the NGIS. Data in the national database are currently insufficient to support reporting of either levels or trends, although work to increase available data is progressing.