Hydrologists typically do the following:

• Measure the properties of bodies of water, such as volume and stream flow
• Collect water and soil samples to test for certain properties, such as levels of pollution
• Apply research findings to help minimize the environmental impacts of pollution, erosion, and other problems
• Research ways to improve water conservation and preservation
• Use computer models to forecast future water supplies, the spread of pollution, and other events
• Evaluate the feasibility of water-related projects, such as hydroelectric power plants, irrigation systems, and waste treatment facilities
• Prepare written reports and presentations of their findings.

Hydrologists use remote sensing equipment to collect data. They or technicians whom they supervise usually install and maintain this equipment. They also use sophisticated computer programs to analyze and model data. They use sophisticated laboratory equipment to analyze chemical samples collected in the field.

Hydrologists work closely with engineers, scientists, and public officials to study and manage the water supply. For example, they work with policy makers to develop water conservation plans and with biologists to monitor marine wildlife. Most hydrologists specialize in a specific water source or a certain aspect of the water cycle, such as the evaporation of water from lakes and streams.