Every year, millions of people visiting New Jersey’s national parks are greeted by facilities that have fallen woefully far behind on repairs.

Potholes that could pass as craters riddle Old Mine Road, the Delaware Water Gap’s main thoroughfare in Hardwick. At Thomas Edison National Historical Park in West Orange, Glenmont Mansion — where the famed inventor lived — is just one of many historic buildings that needs to be restored. And on Sandy Hook in Monmouth County, the seawall keeping Raritan Bay from flooding Fort Hancock’s historic, yet dilapidated, Officer’s Row is crumbling.

Hundreds of millions of dollars need to be spent on repairs at national parks and historic sites in the Garden State, according to the federal government. Billions are needed to address the problem nationwide and as the backlog of repairs builds, the American public risks losing pieces of the nation’s history and some of its more breathtaking scenes.

Federal parks in New Jersey need more than $223 million in repairs; that’s a portion of the $11.9 billion work backlog that the National Park Service faces as of the end of fiscal year 2018.

Aging facilities, increased visitation, and resource constraints have kept the maintenance backlog between $11 billion and $12 billion since 2010, according to the National Park Service.

“The American public, we’re loving our parks to death,” said Brenda Ling, a spokeswoman for the Gateway National Recreation Area.

More than 318 million people visited national parks across the country in 2018, according to the National Park Service. Here are a few of the most serious problems affecting New Jersey’s parks:

- The Gateway National Recreation Area, which includes Sandy Hook in Monmouth County as well as sites in New York, was the fourth-most popular park with more than 9.2 million visitors that year, yet it needs more than $774 million in repairs as of fiscal year 2018, though much of that is for the New York sections. Still, $123.3 million is needed for repairs at the Sandy Hook portion of the park.

- In Sussex County, the Delaware Water Gap National Recreation Area straddles the New Jersey-Pennsylvania border. The park spans roughly 70,000 acres across both states and is a regional draw; more than 3.2 million people visited the park last year, according to the National Park Service. The Delaware Water Gap NRA is facing $147.5 million work backlog as of fiscal year 2018, according to the National Park Service. Of that total, $84.3 million is needed just for repairs on the New Jersey side of the park.

- Thomas Edison National Historical Park in Essex County, which preserves the famed inventor’s home and laboratory, is about $8.4 million behind on repairs. Meanwhile, the Morristown National Historical Park, which is spread across Morris and Somerset Counties and protects key Revolutionary War sites, needs about $7.2 million in work.

The Obama administration began emphasizing the work backlog in fiscal year 2015. That focus has continued under the Trump administration, according to Marcia Argust, the project director for the Pew Charitable Trust’s Restore America’s Parks program.

Argust said that annual federal appropriations to the national parks system have increased in recent years. And the National Park Service, while working under financial constraint, does its best make important improvements to the parks. Last September at Sandy Hook, for example, Gateway NRA celebrated the reopening of the Sandy Hook Lighthouse and the Fort Hancock Post Museum. The lighthouse had been closed for nearly a year for restoration work, while the museum had been closed since 2010 and suffered damage from Hurricane Sandy.

But Argust warns that the annual appropriations are a one-time gift. Her program advocates for permanent funding dedicated to the upkeep of America’s national parks.

“Dedicated annual funding would provide the [National Park Service] with certainty that they could undertake planning, design and contracts for these larger scale or more complicated deferred maintenance projects that are often the more expensive projects,” Argust said.

In Washington, D.C., lawmakers have begun pushing for such a solution.

The bipartisan Restore Our Parks and Public Lands Act, first introduced in the U.S. House of Representatives last July by Rep. Rob Bishop, R-Utah, would create a fund for addressing the needed park repairs. The fund would be financed by money from federal drilling and mining leases. The bill is cosponsored by three of New Jersey’s 12 representatives.

Meanwhile in the Senate, a bipartisan bill called the Restore Our Parks Act was first introduced to the U.S. Senate last June by Sen. Rob Portman (R-OH). Like the House bill, this legislation would use money collected by the federal government from drilling and mining leases to fund park repairs.

Of the New Jersey delegation, Sen. Cory Booker is a cosponsor of the Restore Our Parks Act.

“National parks showcase our nation’s natural beauty and have inspired visitors across New Jersey and America for generations,” said Sen. Booker. “Unfortunately, the $12 billion National Park Service maintenance backlog is preventing critical infrastructure improvement projects from moving forward, including the repair of damage caused by Superstorm Sandy. We have an obligation to ensure that New Jersey’s National Park Service sites are safe, well-maintained, and resilient in the face of future natural disasters.”

Michael Sol Warren may be reached at mwarren@njadvancemedia.com. Follow him on Twitter @MSolDub. Find NJ.com on Facebook.

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