Mountains etched across a clear blue sky and the sparkling waters of high altitude lakes are at the heart of many park visits. However, because threats to the air and water quality of the park are regional and even global in nature, protecting these aspects of the park requires actions that extend beyond park boundaries.
Rocky Mountain National Park has an array of air quality monitoring equipment. A recent report used the data collected over ten years, 1990-1999, to analyze park trends in four categories.
First the good news. Sulfate concentrations, a contributor to acid rain and acidification of lakes, have declined in the park. This positive change is a direct result of improvement in scrubbing equipment at electric power plants. During this same period, and also attributable in part to equipment changes, visual range on the haziest days improved. (Visibility from in Rocky Mountain may exceed 50 miles!) Now the bad news. Ozone concentrations increased between 1990 and 1999. High ozone levels can have an immediate health affect on park visitors. Individuals with asthma, emphysema, and other breathing problems; are most at risk. High ozone levels literally make the air poisonous to breath. Since ozone is produced by the interaction of nitrous oxides, UV light, and heat, Rocky Mountain is particularly prone to increases in ozone on warm summer afternoons with upslope winds. (Car exhaust from Front Range communities is the main source of nitrous oxides.)
Perhaps the most subtle, but potentially the most serious, air quality threat to the park is from nitrogen deposition. Winds from the south and east sweep nitrates and ammonium from car exhaust, factories, and agricultural activity up into the mountains. These types of winds are most prevalent in the spring when higher elevation areas receive most of their precipitation. Nitrate concentrations in precipitation increased significantly during the ten year study period. Nitrogen deposition is causing changes to the park's soil and water chemistry, particularly on the eastern slope. These changes in turn affect algae, aquatic invertebrates, and soil microorganisms - eventually leading to changes in food chains and forest health. Because nitrogen deposition is a regional problem, involving multiple pollution sources, a new strategy to curb emissions is needed if the park is to be protected.
Although water quality is high in park waters relative to much of the country, threats do exist. As described above, nitrogen deposition is a factor influencing soils and waters in the park. In lakes and streams, the impacts of nitrogen deposition grow worse over time as the natural buffering capability of the soil and rock is used up. Eventually, chronic acidification can lead to the loss of many aquatic organisms and entire fish populations. As experience in the northeastern U.S., Canada, and Europe has shown, these changes can be almost impossible to reverse. On an international scale, recent research is demonstrating that volatile chemicals, such as pesticides, can be transported long distances to remote lakes. Because mountains are year-round cold environments, deposited compounds seldom move back into the atmosphere. Such lakes become sinks for pesticides, mercury, and various organic compounds. Over time concentrations can become deadly to lake and stream organisms.
The Loch Vale Watershed -including Sky Pond, Lake of Glass, the Loch, Icy Brook, and adjoining mountainsides - is one of the most studied watersheds in the world. For twenty years scientists have been monitoring chemical inputs to the watershed from wind and precipitation. They have also studied the background chemistry of the local rocks, soils, and vegetation. This work helps distinguish between human impacts and natural processes occurring in this type of alpine and sub-alpine environment. Much of what we know about air and water quality trends in the park comes from this long-term project. These scientists have given us the information necessary to make informed decisions. It is, however, up to society to act on this information. Each of us who enjoys the park has an obligation to take actions in our daily lives that will protect the blue skies and sparkling waters of Rocky Mountain National Park.