Evaporation basins alleviate drainage woes

Sep 11, 2013 by Leslee Hall
Evaporation basins alleviate drainage woes
The Blackwood River travels through Boyup Brook, Bridgetown and Nannup before meeting coastal water at Augusta. Credit: Fritztram

A system employing evaporation basins for use in artificial drainage could improve the health of the Blackwood Basin in the South West within the century, a study has found.

The paper by the CSIRO compared five drainage scenarios with a baseline scenario, which outlines what is expected to happen in the Blackwood Basin in terms of variables like groundwater levels and salinity in this century should the climate of the past 40 years continue.

The findings are based on a modelling study using historical climate and likely future .

The Blackwood Basin has been experiencing long-term increases in groundwater levels as a consequence of large-scale clearing in the past two centuries.

The clearing has led to increased stream salinity and land salinisation.

Only one of the drainage scenarios was found to be able to improve the health of the Blackwood Basin compared to the baseline scenario – the Evaporative Basin (EB) model.

CSIRO Land and Water Principal Research Scientist and lead author Riasat Ali says the EB model assessed the feasibility of constructing basins at the outlet of each of the 111 subcatchments in the basin to store drainage discharge from an artificial .

Under the EB system, stream salinities were projected to reduce at all subcatchments by at least 30 per cent, and up to a maximum of 61 per cent in the Beaufort River.

Mean annual flow at all sites was also projected to reduce, while it was found there would be substantial reductions in overflow frequencies across the .

This is compared to the baseline model, which found that the long-term impacts of doing nothing – that is, having no artificial drainage or salinity in place – would result in increases in streamflow and salinity.

There would also be continuing increases in average and increased overflow frequencies.

"All drainage discharge management strategies, except discharge management by evaporation basins….are likely to have adverse impacts on the lower Blackwood River from higher salinity levels than are expected under the baseline scenario," Dr Ali says.

"This [EB] strategy was assessed as infeasible economically due to prohibitive construction and maintenance costs of evaporation basins," Dr Ali says.

Dr Ali says any future regional drainage scheme in the Blackwood Basin could use the findings of this project to select options which were both technically and economically feasible.

The research project was completed as part of the Engineering Evaluation Initiative, managed by the Department of Water.

Explore further: Irrigation can give rise to increased precipitation

More information: www.water.wa.gov.au/understanding+water/Salinity/Engineering+evaluation+initiative/default.aspx

add to favorites email to friend print save as pdf

Related Stories

Irrigation can give rise to increased precipitation

Apr 17, 2013

PhD candidate Obbe Tuinenburg defended his doctoral thesis on the 15th of April, 2013. His research related to the effects of large-scale irrigation in India on the atmosphere and rainfall. One of the conclusions ...

Recommended for you

Book offers simplified guide to shale gas extraction

14 minutes ago

The new book, "Science Beneath the Surface: A Very Short Guide to the Marcellus Shale," attempts to offer a reader-friendly, unbiased, scientific guide needed to make well-informed decisions regarding energy ...

New approach needed to deal with increased flood risk

33 minutes ago

Considering the impacts of climate change on flood risk may not be effective unless current risk is managed better, according to new research from the University of Bristol published today in the Journal ...

Researchers question emergency water treatment guidelines

19 hours ago

The Environmental Protection Agency's (EPA's) recommendations for treating water after a natural disaster or other emergencies call for more chlorine bleach than is necessary to kill disease-causing pathogens ...

User comments : 0

More news stories

Melting during cooling period

(Phys.org) —A University of Maine research team says stratification of the North Atlantic Ocean contributed to summer warming and glacial melting in Scotland during the period recognized for abrupt cooling ...

Robotics goes micro-scale

(Phys.org) —The development of light-driven 'micro-robots' that can autonomously investigate and manipulate the nano-scale environment in a microscope comes a step closer, thanks to new research from the ...

Biologists help solve fungi mysteries

(Phys.org) —A new genetic analysis revealing the previously unknown biodiversity and distribution of thousands of fungi in North America might also reveal a previously underappreciated contributor to climate ...