Casper Field Office

Managing Drought on the Rangelands

Wyoming has and will experience periods of extended and significant droughts thereby limiting available forage and stock water. To protect the long-term health of rangeland vegetation, watershed stability, site productivity, and wildlife habitat the Casper Field Office has developed a process to resolve temporary grazing management issues and prevent undue degradation to the public lands as a result of drought. The percentage of federal range and riparian areas within a pasture or allotment located on public lands will be factored into management decisions.

The following criteria will be used to determine when management actions may be needed to protect these resources.


  • Precipitation levels are at 25% or more below the long-term average;

Forage Use on Upland Areas

  • There is heavy use (60%+) of plants preferred by livestock, especially in key areas (areas that are near a dependable water source or salting locations).
  • When 40% use has been reached on key areas that received heavy use (60%+) the previous year and are in an extended drought situation.

Riparian Areas

  • A four- to six-inch stubble height (where applicable) will be managed for on riparian zones at the end of the grazing season.

Regrowth Potential

  • The potential for regrowth of upland grass species is limited by soil moisture. Once soil moisture is out of grasses' root zone (about 8"-10" deep for deep-rooted species) growth ceases. During drought, this occurs considerably earlier in the growing season.
  • Within riparian areas livestock would be removed early enough to allow maximum regrowth prior to full maturity in order to reach a 4- to 6- inch stubble height.

Diet Shift to Shrubs

  • On wildlife winter ranges use of shrubs will be monitored.
  • Livestock could be moved/removed when livestock diets have shifted from grasses and forbs to shrubs.
  • Water Availability/Distribution
  • Lack of natural water sources (dry springs and reservoirs).
  • Level of use/stubble height in areas serviced by stockwatering troughs or wells will dictate livestock removal.
  • Hauling water or drilling wells may be needed on ungrazed areas.


  • Grazing use in weed infested areas will be monitored. When use levels reach 40% on key forage areas moving livestock will be considered.

If a possible problem area is identified, a rangeland management specialist will determine if drought-related actions are needed. A team consisting of a soil scientist, hydrologist, wildlife biologist, engineering technician, the affected grazing lessee(s), a state representative, and any known interested publics will be formed. This team will inspect the site and collect data or other information and determine if one or more of the criteria apply.

If a determination cannot be made by the team, the facts to initiate an action will be presented to the field office manager for a final decision. If one or more of the criteria apply and a remedy is required, the team will identify actions to mitigate the problem(s) and arrive at a solution.