General

Multipurpose reservoirs may be managed to balance some or all of the following activities:

• Water supply
  Water supply
  Water supply is the provision of water by public utilities, commercial organisations, community endeavours or by individuals, usually via a system of pumps and pipes...
  
  
• Flood control
  Flood control
  In communications, flood control is a feature of many communication protocols designed to prevent overwhelming of a destination receiver. Such controls can be implemented either in software or in hardware, and will often request that the message be resent after the receiver has finished...
  
  
• Soil erosion
• Environmental management
  Environmental management
  Environmental resource management is “a purposeful activity with the goal to maintain and improve the state of an environmental resource affected by human activities” . It is not, as the phrase suggests, the management of the environment as such, but rather the management of the interaction and...
  
  
• Hydroelectric power generation
• Navigation
  Navigation
  Navigation is the process of monitoring and controlling the movement of a craft or vehicle from one place to another. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks...
  
  
• Recreation
  Recreation
  Recreation is an activity of leisure, leisure being discretionary time. The "need to do something for recreation" is an essential element of human biology and psychology. Recreational activities are often done for enjoyment, amusement, or pleasure and are considered to be "fun"...
  
  
• Irrigation
  Irrigation
  Irrigation may be defined as the science of artificial application of water to the land or soil. It is used to assist in the growing of agricultural crops, maintenance of landscapes, and revegetation of disturbed soils in dry areas and during periods of inadequate rainfall...
  
  

The multipurpose nature of these facilities dictates that the agencies which manage them are responsible for balancing competing demands. For example, managers responsible for hydroelectric power generation often want to keep lake levels as high as possible, since the water stored in the reservoir serves as a kind of "fuel

Fuel

Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air...

" for their generators. However, managers responsible for flood control often want to keep lake levels as low as possible to provide the maximum amount of storage capacity for rainwater runoff.

One agency often associated with multipurpose reservoir management is the Tennessee Valley Authority

Tennessee Valley Authority

The Tennessee Valley Authority is a federally owned corporation in the United States created by congressional charter in May 1933 to provide navigation, flood control, electricity generation, fertilizer manufacturing, and economic development in the Tennessee Valley, a region particularly affected...

.