Blue vs. Green Water (IMAGE) ETH Zurich Caption In an average summer, less water evaporates through vegetation; in a hot summer accompanied by dry conditions, the opposite is true, which amplifies the lack of water in streams. Credit ETH Zurich / Michael Stuenzi Usage Restrictions Images published on ETH News may be used by other media and online portals only if ETH Zurich is specifically mentioned as the copyright holder and only in connection with the relevant ETH News article. Further distribution of images – for example, via download links – is permitted only with the approval of the editorial team. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.