Secondary impacts stem from inadequate control of soil erosion at construction sites, improper waste treatment and disposal, flooding of upland plant communities, stream bank erosion, disturbance, and noise. In aquatic ecosystems, the principal damage has occurred through artificial drainage, landfill operations, excessive water diversions, and improper disposal of industrial waste. Problems affecting the atmospheric ecosystem are improper disposal of industrial and municipal waste and improper pesticide application. For the region surrounding the ANG Coal Gasification Plant, specific concerns of the Fish and Wildlife Service relate to migratory birds and their habitat. Terrestrial woodland ecosystems are of primary importance.
Biologists are particularly concerned about hardwood draws and the Missouri River bottomland forest.
Current threats to hardwood draws include destruction of the natural vegetation by mining activities, degradation from overgrazing, agricultural soil erosion, pesticide drift, and possible injury to the vegetation from energy-related air pollution. It would be important to find out whether hardwood draws can be avoided by coal mining operations and whether hardwood draws surrounded by reclaimed land could still support their original biota. Much of the remaining acreage is overgrazed and on these areas tree reproduction has ceased. Because it lies in a topographic low and is downwind from the area of intensive energy development, this forest also may face an increased chance of damage from energy-related air pollution. Closing of Garrison Dam in 1955 stopped natural spring flooding of the cottonwood forest.