Prevailing winds in the region are generally from the west, but the most intense episodes of nitrogen deposition on the east side of the Continental Divide occur relatively infrequently when emissions from eastern Colorado are transported into the Park through upslope weather events. Total deposition on the east side of the Park is associated less with the slow trickle of nitrogen that comes with the prevailing winds from the west and more with predictable, episodic events that lead to significant deposition of nitrogen in relatively short time frames, usually in the spring and fall.
A variety of sources contribute to nitrogen deposition in Rocky Mountain National Park (RMNP). Approximately 40% of the deposited nitrogen is oxidized (nitric acid and nitrate formed from atmospheric reactions of NOx) and originates from sources of combustion such as automobiles, power plants, generators, fires, and industrial sources. Approximately 60% of the deposited nitrogen is reduced (ammonia and ammonium) and comes primarily from manure, fertilizers, fires, and natural emissions from soils.
For the reduced nitrogen (ammonia and ammonium), roughly 55% originates in Colorado and the remaining 45% comes from out-of-state sources as far away as California.
During years with average wildfire activity in Colorado, it’s estimated that around 20% of the total wet nitrogen deposition could be attributed to manure and fertilizer in the Central Front Range, where the upslope events predicted by the CANEWS are the most common. During years with high wildfire activity (like 2021), the contribution from the Central Front Range is significantly reduced.
Given the variety of sources contributing nitrogen to RMNP, no one solution will be sufficient to achieve the target resource management goal of reducing wet deposition to 1.5 kg N/ha/ yr. Instead, a combination of solutions must be applied, informed by science regarding source apportionment and emissions mitigation.
Emissions of NOx reaching RMNP may be reduced through improved combustion systems and reductions of industrial and tailpipe emissions. It is expected that tighter fuel-economy standards and new technologies required to reduce emissions from large industrial sources through other air quality regulatory programs addressing ozone and visibility will also reduce deposition of NOx into the Park.
Ammonia emissions reaching RMNP may be reduced through improved feed conversion efficiency by livestock producers, improved methods of manure management, improving nitrogen use efficiency of crops, and matching fertilization rates with plant needs on farms and in residential and commercial landscapes. Methods of reducing ammonia emissions from animal and crop production systems can be found here. The National Air Quality Site Assessment Tool (NAQSAT) can also be used to identify opportunities to reduce ammonia emissions from a given livestock operation.
Significant gaps in understanding still exist regarding ammonia emissions from other sources such as fires, forests, and native grasslands. As new discoveries are made, the suite of available emissions reductions strategies will evolve and improve.
A similar weather-based prediction system in Kansas has effectively reduced the movement of smoke emissions from the Flint Hills into populated areas, aiding in attainment of National Ambient Air Quality Standards for ozone. It is expected that, once the prediction model is up and running, nitrogen deposition in RMNP from eastern Colorado will be reduced.
Atmospheric scientists at Colorado State University have analyzed the weather conditions during past deposition episodes and identified the key meteorological features of events leading up to these episodes. Weather prediction models are then used to determine when similar patterns (such as easterly winds following a period of stable conditions) are likely to occur in the next few days. If the predicted conditions are very similar to those known to produce deposition episodes in the past, a warning may be issued. Based on the results of both the weather predictions and feedback from participating producers, the model will be refined and optimized to most effectively reduce nitrogen transport from eastern Colorado into RMNP.
Why should agricultural producers care about nitrogen deposition in the Park?
Just as most agricultural producers want to preserve their operations and be able to pass them down to the next generation, RMNP is a national treasure to be preserved and handed down. By reducing the impacts on ecosystems in RMNP, agricultural producers are stewarding our natural resources. For more information, see Agricultural Best Management Practices: Helping to Reduce Nitrogen Impacts at Rocky Mountain National Park.
Participants will receive warnings of impending upslope events and will be asked to change the timing of any manure management activities planned during the warning period or by implementing other practices for reducing emissions. Participants will also be asked to respond to those warnings by indicating whether they are able to change their practices in response to issued warnings. Responses to issued warnings are self-reported, voluntary, and should take less than five minutes.
To participate in the pilot project, sign up here
More information about the Rocky Mountain National Park Initiative, ecosystem impacts at RMNP, environmental monitoring, and activities related to reducing nitrogen deposition, can be found at the homepage of the RMNP Initiative.
For more information about the pilot warning system, fill out our “Contact Us” form.