Drought
Climatologists define drought as a period of abnormally dry and/or unusually hot weather sufficiently prolonged for the corresponding deficiency of water to cause a "serious hydrologic imbalance". More simply put, too dry and/or too hot for too long. Interpreting what is "too dry" or what is "too long" is difficult. What is known is that when a serious hydrologic imbalance occurs in Minnesota, soil moisture reserves, groundwater supplies, lake levels and stream flows are negatively influenced. Water-dependent industries including agriculture, public utilities, forestry, and tourism are profoundly affected. Although droughts are not as sudden as floods, the economic aspects of droughts can be just as significant.
Because long-term (months/years) climate variations are unpredictable, drought is largely unpredictable. Once a drought commences, it is not known whether it is the 6th month of an 8-month drought or the 6th month of an 8-year drought.
Monitoring drought conditions
Because of the unpredictable character of drought, water resource conditions are monitored (stream flow and lake level for example) and water use is tracked. DNR Waters follows emerging patterns, relying heavily on precipitation departure and precipitation ranking maps and the National Drought Mitigation Center's Drought Monitor.
2007 Drought Information Resources
DNR Waters Drought Procedures
DNR Waters heightens its "watch" when key climate and water resource conditions warrant (via ongoing climate and resource monitoring), and begin to act when the "warning" stage is reached by following the Minnesota Drought Response Plan 
, which identifies key resource triggers, agency coordination and mitigation measures.
Should conditions warrant, DNR Waters may be required to suspend surface water appropriation permits as dictated by its Surface Water Appropriation Permit Issuance and Suspension Procedures (1.3 MB). The DNR Division of Waters may also be involved in well interference resolution.
DNR Waters has played an important role in the development of a Mississippi River Low-Flow Management Plan .
