Climate change and land management practices could be affecting the total amount of groundwater and surface water in the Hunter Valley, and also increasing levels of salinity.
This is the view of researchers from The Australian National University and Southern Cross University who are currently researching the interaction between surface water, groundwater and salinity in the Wybong and Wollombi catchments.
These findings will assist land holders and natural resource managers to evaluate their programs, and ensure water quality and quantity in the region remain at acceptable levels.
“Traditionally salinity monitoring involves the measure of input and outputs of salts from catchments,” explains lead researcher Dr Ben Macdonald from the Fenner School of Environment and Society at ANU. “We’ve found that since 2000, the long term daily flow out of the Wybong Catchment has reduced from 83 megalitres per day to under 20 megalitres per day. This is in part due to the long drought that has occurred in the region since the turn of the century. We are now investigating how surface water yields have decreased in relation to seasonal rainfall.
“There has been an increase in stream salinity because the saline ground water inputs are not diluted due to reduced stream flows,” Dr Macdonald explains. “This study has found that landscape weathering, and the dissolving of rocks and soils, are important sources of salts. These salts are contributing to salinisation of some Hunter landscapes. Importantly, increased temperatures and changed rainfall regime due to climate change and land management practices could increase weathering rates and affect salinisation.”
The scientists are concerned about the continuing effects of over extraction of ground water, as they’ve found that some sources are very old. They’ve also found that fresh stream and alluvial ground waters often raft on top of saline waters. “These waters must be carefully managed to prevent intrusions of these saline waters into the fresh water resources,” Dr Macdonald says. “We’re developing a ground and surface water model for the assessment of ground water trends to help water users in the Hunter ensure the sustainability of their water.”
An important outcome of this research is the understanding of the surface and ground water interactions and the factors that are controlling salinity. The research has been funded by the Australian Research Council and the NSW Salt Action Program via the Hunter - Central Rivers Catchment Management Authority. The NSW Department of Water and Energy has also been providing data and knowledge to the research.
Source: Australian National University
Related stories:
Spiky Probe on NASA Mars Lander Raises Vapor Quandary
(PhysOrg.com) -- A fork-like conductivity probe has sensed humidity rising and falling beside NASA's Phoenix Mars Lander, but when stuck into the ground, its measurements so far indicate soil that is thoroughly and perplexingly dry.
Amateur Astronomers See Perseids Hit the Moon
One, the old-fashioned way: Find a dark place with starry skies and count the meteors streaking overhead. Two, the new way: Find a dark place with starry skies and then completely ignore the meteors. Instead, watch the Moon. That's where the explosions are.
Evolving designer ecosystem sheds light on unintended consequences
Amidst the semi-arid stretches of Phoenix, a visitor might blink twice at the sight of a sailboat cutting across the horizon. Tempe Town Lake, on the northern edge of Arizona State University (ASU), is just one of a multitude of lakes, small ponds, canals and dams combining flood control, water delivery, recreational opportunities and aesthetics, and altering perception of water availability and economics in the area.
Switchable bio-adhesion
(PhysOrg.com) -- Researchers have developed a new type of property-changing polymer: It is water-repellent at 37°C, which makes it an ideal culture substrate for biological cells. At room temperature it attracts water, allowing the cells to be detached easily from the substrate.
Antarctic research helps shed light on climate change on Mars
Researchers examining images of gullies on the flanks of craters on Mars say they formed as recently as a few hundred thousand years ago and in sites once occupied by glaciers. The features are eerily reminiscent of gullies formed in Antarctica's mars-like McMurdo Dry Valleys.
Phoenix Mars Lander Digs Deeper as Third Month Nears End
(PhysOrg.com) -- The next sample of Martian soil being grabbed for analysis is coming from a trench about three times deeper than any other trench NASA's Phoenix Mars Lander has dug.
Mid-Depth Soil Collected for Lab Test On NASA's Mars Lander
NASA's Phoenix Mars Lander has scooped up a soil sample from an intermediate depth between the ground surface and a subsurface icy layer. The sample was delivered to a laboratory oven on the spacecraft.
Researchers Isolate Microorganisms That Convert Hydrocarbons to Natural Gas
(PhysOrg.com) -- When a group of University of Oklahoma researchers began studying the environmental fate of spilt petroleum, a problem that has plagued the energy industry for decades, they did not expect to eventually isolate a community of microorganisms capable of converting hydrocarbons into natural gas.