CHICAGO The venerable Washington Post may begin to charge readers to view its articles online, the Wall Street Journal reported Thursday, citing unnamed sources with knowledge of the situation. The move could take effect next year, the newspaper said, along with an increase in the print newspaper’s newsstand price. In the wake of the New York Times’s successful implementation almost two years ago of a so-called “metered” paywall — in which customers who are not print subscribers are allowed to read 10 stories online for free before being asked to pay $ 15 a month for access — many other newspapers have followed suit or made plans to do so. Precipitous declines in print advertising revenue have plagued the industry since 2006, more than offsetting gains on the digital front, and newspapers are scrambling to find another major revenue source. This is a time of change at the Post; last month, the newspaper said Marcus Brauchli, its executive editor since 2008, will step down and be replaced by Marty Baron, editor of the Boston Globe, who assumes the role Jan. 2.