People watch as two climbers vie to become the first in the world to use only their hands and feet to scale a sheer slab of granite and make their way to the summit of Yosemite National Park’s El Capitan in January 2015. (AP/Ben Margot)

The National Park Service is increasingly neglecting its trails, roads and visitor centers because of recent budget constraints, according to a report from the agency this week.

The park service said it delayed an estimated $11.5 billion worth of needed maintenance projects last year due to funding shortages, with the total growing nearly 2 percent compared to 2013. The backlog has reached its highest point since President Obama took office, expanding nearly 13 percent during that time.

Rising construction costs have heightened the agency’s budget challenges, with upkeep growing more expensive as park facilities fall further into disrepair, according to the report. (Here’s a list of deferred projects by state and by park).

Data: National Park Service. (Graph by Josh Hicks/The Washington Post)
Data: National Park Service. (Graph by Josh Hicks/The Washington Post)

The mounting maintenance concerns come as the National Park Service prepares to celebrate its 100th year in August 2016.

“As we invite more Americans to discover the special places in the National Park System during our centennial celebration, we need to have facilities that can accommodate them and provide the best possible experience,” agency director Jonathan Jarvis said in a news release on Monday.

The National Park Service has asked Congress for $243 million in new funding over the next 10 years to restore its non-transportation facilities to good condition. President Obama’s 2016 budget proposal requests an additional $150 million to pay for major transportation projects on federal lands, including national parks.

Park roads and bridges accounted for about half of the backlog last year, according to the report.

Craig Obey, senior vice president for government affairs with the National Parks Conservation Association, said Congress needs to take “immediate and substantive action” to prevent further maintenance delays.

“Failing to provide for the system’s basic maintenance needs has eroded our most treasured landscapes and historical sites,” Obey said in a statement on Monday. “Next year’s centennial of the National Park System is the perfect opportunity for Congress to renew its commitment to protecting America’s most special places.”

Correction: An earlier version of this article incorrectly said the White House requested $243 billion for non-transportation facilities over the next 10 years. The figure has been corrected to $243 million.