Visibility in Hercules Glades Wilderness, Taney County, Missouri: a Study of Baseline Conditions
The protection of visibility resources became a priority to Federal Land Managers with the passage of the Clean Air Act Amendments of 1997. A nationwide visibility monitoring program was established to remedy current and prevent future visibility degradation in Class I airsheds. The Mark Twain National Forest was mandated to collect baseline visibility data in Hercules Glades Wilderness in Taney County, Missouri. With the establishment of baseline conditions, future monitoring activities can use these data as the beginning standard. The recommendation was that monitoring should be continued for a ten year baseline with consistent data collection of all variables. However, data at Hercules Glades was only collected for five years from 1991 to 1996. Every effort should be made to maintain the same methodologies throughout the study period, or provisions made to smooth transition between one methodology and another. It was discovered that Hercules Glades suffers from uniform/regional haze 59 percent of the time, and standard visual range (SVR) decreased each year from 1991 to 1993. The winter seasons have the lowest percentage of uniform haze and the greatest SVRs, while the summer seasons typically have the lowest SVRs. Human perceptions were concurrently collected to establish visibility thresholds to assist the United States Forest Service in determining the levels of protection this Class I airshed may require. Wheather data were collected that are available for future analyses. These data and thesis findings should be incorporated into the long range management plan for the Mark Twain National Forest. The Hercules Glades Visibility Monitoring Project was an example of how the private sector, state academic agencies and federal organizations can work together for the achievement of a common goal. Cooperative efforts should be continued where common interests exist.
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