Death Valley, Calif. ? The weather-beaten roof of the National Park Service Visitor Center here is so dilapidated that a ceiling tile recently fell and struck a woman standing in the gift shop.

With relatively few park rangers available to patrol the massive desert parkland and salt flats, vandals and thieves routinely cart off priceless Indian rock art and remnants of historic ghost towns. And funding for scientific research is so meager that newly discovered microscopic life forms in underground springs dating to the last ice age have gone largely unexplored.

“Every park staff is struggling with operational issues  not having enough staff and funds to do what we know we need to protect the parks and serve the users,” said James Reynolds, superintendent of Death Valley, the largest national park outside Alaska.

Reynolds is not alone in his concern. Park officials, conservationists and lawmakers throughout the country are troubled by the declining state of many of the 385 national parks and sites as officials brace for what they expect to be another banner year of tourism. The problems are especially dismaying to some because of President Bush’s earlier promise to turn the situation around.

During the 2000 campaign, Bush said the national park system was in “worse shape than ever” and vowed to erase a huge, $4.9 billion backlog of maintenance and road improvement projects within five years. So far, the administration has managed to make only a tiny dent in that backlog, while many of the nation’s most prominent parks continue to suffer from years of budget parsimony.

At Yellowstone National Park, for example, repeated spills at worn-out water treatment plants have dumped untreated waste into the pristine waters of Yellowstone Lake, the Firehole River and other park waterways, according to a comprehensive national survey by Americans for National Parks. Acadia National Park in Maine lacks the staff to adequately patrol the park’s complex, 115-mile boundary  leaving miles of roads and trails vulnerable to damage from illegal snowmobile and all-terrain vehicle use, trail cutting and poaching.

Conservationists say the operating and maintenance problems have festered for more than a decade, as relatively modest yearly spending increases have failed to accommodate the system’s expansion, aging infrastructure and steady increase in tourism  with more than 285 million visitors annually. While environmentalists hail the president’s interest in national parks, they say that he has yet to back up his commitment with adequate funding, and that the problems go well beyond the hefty backlog of construction projects and improvements.

“First and foremost, the administration has to put in the financial resources to stop the degradation of clean air and clean water, wildlife and all the historic and cultural features associated with our national park system,” said Chuck Clusen, director of the Natural Resources Defense Council’s national parks project.

Administration officials say the problems they inherited were far greater than they imagined, which has forced a major reassessment of park needs. They said they are doing the best they can with limited funds to undertake the most urgent backlog construction projects while addressing more immediate maintenance and operating problems.