President Obama will announce details Friday for a $1 billion Veterans Job Corps that the White House says will put up to 20,000 veterans to work over the next five years on projects to preserve and restore national parks and other federal, state and local lands.

Veterans Affairs Secretary Eric K. Shinseki on Thursday described the program as “a bold new effort” to lower the high unemployment rate for post-Sept. 11 military veterans, which stood at 13.1 percent in December. The government estimates that 250,000 post-Sept. 11 veterans are unemployed.