. 24/7 Space News .
Monitoring Chernobyl's Radioactive Floods

23 October 2000 High water in the neighbourhood of Chernobyl, April 1999 (courtesy Alexey Ischuk of ECOMM)
Gothenburg - Oct. 25, 2000
Chernobyl is a nuclear hot spot. Radioactive dust covers the area around the nuclear plant which exploded in 1986, and debris from the clean-up is isolated in earthen bunkers. The contamination still spreads, however, carried by water toward the nearby Pripyat and Dnieper rivers.

Presenting their results at the ERS - Envisat Symposium, organised by the Europan Space Agency (ESA) in Gothenburg, Ukrainian scientists explained how they are using ESA satellite images to monitor flooding which threatens the 10 million people living in the Dnieper basin with radioactive contamination.

The area around Chernobyl is regularly threatened by Spring floods, as the snows of the winter melt and water rushes through hundreds of tributaries towards the two great rivers. In the years after the disaster, Ukrainian scientists developed a hydrographic model of the area around the damaged plant, which provided some warning of impending flooding.

As Alexey Ischuk of ECOMM in Kiev explains, "There have been large changes in the hydrological system over the years, through deforestation on slopes and man-made alterations to riverbeds. These changes will change the speed and depth of the flooding significantly."

The radioactive no-go area around Chernobyl established in 1986 was expanded in 1997 to encompass about 2500 sq. km, and it is estimated that this zone contains over 21 million Curies of radiation. "The main way the radioactivity is carried out of the zone is by underground water and by surface washing into the Pripyat riverbed and further to the Dnieper," explains Ischuk.

"But it is estimated that the underground water will take 50 years to reach the river, while the pollution from flooded areas and the isolated reservoirs can be washed into the river in a few days as the floods recede. That's why an evaluation of the flood areas using remote sensing data and GIS is the most important problem facing Chernobyl zone researchers."

In early April 1999, the Pripyat River reached unexpectedly high levels, bursting its banks and inundating over 10 sq. km. around the Chernobyl plant. ECOMM and INFOCenter Chernobyl had modelled the expected flooding, and identified the most dangerous place, where overflow of a dam containing contaminated waste would carry radiation directly into the Pripyat.

To validate their modelling, the Ukrainian team turned to ESA. ESA's ERS-2 satellite, launched in 1995, gathers remote sensing data on global scale. The satellite, as well as its successor Envisat, which is due for launch in mid-2001, carries a Synthetic Aperture Radar (SAR) among other instruments. ERS-2 had obtained a SAR image of the area on 5 April.

SAR images show flooded areas very clearly, since the distinctive "signature" of reflection from water is very different from land and vegetation. Comparing the actual flooded areas visible in the SAR image with the predictions of their hydrographic model, Ischuk and the team were able to refine their model, and make predictions of the amount of radiation released by the floods.

According to Ischuk, further work is still needed -- for example, to derive a higher resolution digital elevation model of the basin using SAR interferometry techniques. Even so, he says, "We have improved our models considerably, and using the radar images has been a very important addition to the methods and techniques we can use to help understand, and eventually solve, this very difficult problem."

Related Links
ERS-Envisat Symposium
ERS Homepage
Search SpaceDaily
Subscribe To SpaceDaily Express

Disaster Management Can Have Space Support In One Call
Paris - Oct. 29, 2000
As from 1 November countries where a natural or technological disaster has occurred will be able to enlist emergency support from the space facilities of the European Space Agency (ESA), the Centre National d´┐ŻEtudes Spatiales (CNES, France) and the Canadian Space Agency (CSA) by simply calling a confidential telephone number.

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once

credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly

paypal only

The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.