To Keep The Water From Evaporting

96 میلیون توپ پلاستیکی به اندازه یک سیب را پشت سد های امریکا کالیفرنیا قرار دادند که این عمل از بخار شدن 300میلیون گالن آب در سال جلوگیری میکنه. 

 Officials recently released 96 million floating 'shade balls' into the 75-acre Los Angeles Reservoir in Sylmar, California.

The black plastic balls are designed to help protect the water against dust, rain, chemicals and wildlife, as well as prevent 300 million gallons of water from evaporating each year