NEW environment minister Greg Hunt recently announced 50 large coal and coal seam gas developments to be pushed through Australia's environmental approval process, including assessment under the new federal "water trigger" introduced in early 2013.
The proposed mines are predominantly in NSW and Queensland, already sites of conflict over coal exports and CSG.
A draft report from the Productivity Commission highlights the central issue: proponents of coal and CSG projects want rapid and simple assessments, while communities and environmental groups want baseline studies, more information and cumulative assessment. All of which cost time and money.
Mr Hunt's announcement follows strong indications that the federal government wishes to speed up environmental approvals.
The decision to start assessing these 47 projects en masse and so quickly after the election seems to match the pre-election rhetoric.
Mr Hunt has also suggested support for adopting an upper time limit, such as nine months for the assessment process.
However, we need to treat these assessments with caution. For many communities that will be affected by the projects the biggest concern is groundwater.
Groundwater: a sensitive resource
Most of the proposed mines will affect groundwater, in many cases from aquifers already used by people and important ecosystems.
It's not realistic to expect proper groundwater assessments be conducted in a nine-month period, or under any other form of "fast-tracking". Let's have a look why.
Currently, groundwater supplies about 30% of Australia's total water use. It is an important resource in a country where most easily accessible surface water is already allocated or used.
It is expected to meet a significant proportion of future water demand and help to buffer against a changing climate.
Its worth to the economy is in billions of dollars every year. Many ecosystems also depend on groundwater; recent mapping shows that groundwater is vital for ecosystems right across Australia.
Groundwater can be a highly sensitive resource for a number of reasons.
In particular, the time between an impact on groundwater pressure in one area, and a corresponding change in flux of groundwater somewhere else can be lengthy.
Aquifers, particularly deep aquifers, can take many thousands of years to recharge and they can be quickly to contaminated or depressurised, but more difficult to fix.
Uncertainty demands caution
Our power as a scientific community to model impacts of major projects on groundwater is still limited, despite today's sophisticated data collection and computer modelling techniques.
All models used by hydrogeologists are characterised by uncertainty. For example, we generally can't determine exactly by how much or how quickly one aquifer may register changes in water pressures in response to de-watering somewhere else.
Rather, a range of possible outcomes, with a certain level of confidence could realistically be provided.
Similarly, it is not easy to predict exactly how quickly pollution will move through an aquifer, and whether or when it might ultimately reach a wetland or stream.
To make these predictions, extensive field studies and baseline monitoring data need to be put into our models.
In the words of one of our most eminent hydrogeology professors, Dr Craig Simmons, it is time for hydrogeologists to "level" with decision-makers and communities.
Groundwater models do not give us a crystal ball to predict future impacts, and they will produce highly uncertain results if time, budget or field data are too limited.
While proponents and governments may not like to hear it, a long period of data collection and hydrogeological investigation is needed to make confident predictions with groundwater models.
Proper assessment of the impacts of large coal mining and coal seam gas developments on groundwater are going to need time and resources.
The new government, proponents of major projects and communities need to bear these issues in mind.
Approvals may take a long time but to protect such a precious resource as groundwater, it is worth taking it.
This article was originally published at The Conversation. You can source the original article here.
Matthew Currell is a lecturer in hydrogeology at RMIT University's School of Environmental Engineering.