Over the years, human activities have impacted the natural resources of Grand Canyon National Park in many ways. Humans have introduced non-native plant and animal species into the park, which out compete native flora and fauna for space, food and water. Air pollution has routinely drifted into the Canyon from metropolitan areas and nearby coal-fired power plants, affecting visibility from scenic vistas. Water in some streams has been tainted with fecal coliform from trespass cattle and from human waste. The construction of Glen Canyon Dam in 1963, irreversibly altered the riparian and aquatic ecosystems within the park. The natural quiet of Grand Canyon has been disturbed by rumbling aircraft noise, and forest landscapes have been altered by decades of wildland fire suppression.
Today, many laws have been passed and programs put in place to protect and restore the natural wonders of the Grand Canyon in order "to leave them unimpaired for the enjoyment of future generations." Park scientists use integrated pest management techniques to eradicate and relocate non-native and pest species. A coal-fired power plant in Page has installed scrubbers in smoke stacks to reduce air pollution. Fences have been erected along the park boundaries to keep out trespass cattle, and hikers and river runners are being educated on the proper methods of human waste disposal. Stakeholders from federal and state agencies, Native American tribes, and environmental and recreational organizations have partnered to create the Glen Canyon Dam Adaptive Management Program to recommend modifications to dam operations to benefit natural and cultural resources in Grand Canyon National Park and Glen Canyon National Recreation Area. Special no flight zones have been created to preserve natural quiet in remote areas of the park and prescribed burning and forest thinning are natural resource management tools used to restore forest landscapes and reduce wildfire hazards.