Hydrologists use their knowledge of the physical makeup and history of the Earth to protect the environment, study the properties of underground and surface waters, locate water and energy resources, predict water-related geologic hazards, and provide environmental site assessments.

Some hydrologists conduct research to identify, abate, and eliminate water-related hazards that affect people, wildlife, and their environments. Hydrologists may work to analyze measurements or observations of air, water, and soil to determine ways to clean and preserve the environment. Understanding the issues involved in protecting the environment—degradation, conservation, recycling, and replenishment—is fundamental to the work of hydrologists. They often use this understanding to design and monitor waste disposal sites, preserve water supplies, and reclaim contaminated land and water to comply with federal environmental regulations. They also write risk assessments, describing the likely affect of construction and other environmental changes; write technical proposals; and give presentations to managers and regulators.

Hydrologists study the quantity, distribution, circulation, and physical properties of bodies of water. Often, they specialize in either underground water or surface water. They examine the form and intensity of precipitation, its rate of infiltration into the soil, its movement through the Earth, and its return to the ocean and atmosphere. Hydrologists use sophisticated techniques and instruments. For example, they may use remote sensing technology, data assimilation, and numerical modeling to monitor the change in regional and global water cycles. Some surface-water hydrologists use sensitive stream-measuring devices to assess flow rates and water quality.

Hydrologists often begin their careers in field exploration or, occasionally, as research assistants or technicians in laboratories or offices. They are given more difficult assignments as they gain experience. Eventually, they may be promoted to project leader, program manager, or some other management and research position. Most entry-level hydrologists spend the majority of their time in the field, while more experienced workers generally devote more time to office or laboratory work. Hydrologists that work outside may work in warm or cold climates, and in all kinds of weather. Frequent travelling may be required to meet with prospective clients or investors.

Hydrologists must have good interpersonal skills, because they usually work as part of a team with other scientists, engineers, and technicians. Strong oral and written communication skills also are essential because writing technical reports and research proposals and communicating results to company managers, regulators, and the public are important aspects of the work. Because international work is becoming increasingly pervasive, knowledge of a second language can be an advantage. Those involved in fieldwork must have good general health and physical stamina.


Urban planners; land developers; builders; management, scientific and technical consulting services; architectural and engineering firms; waste management facilities; federal, state, and local governmental agencies and other miscellaneous professional, scientific, and technical services firms.


In some cases, a bachelor’s degree in a hydrologic science is sufficient for positions consulting about water quality or wastewater treatment. A master’s degree is the minimum educational requirement for most entry-level applied research positions in private industry, in state and federal agencies, and at state geological surveys. A doctoral degree generally is necessary for college teaching and most research positions.

Combining environmental science training with other disciplines such as engineering or business, qualifies these scientists for the widest range of jobs. Computer skills are essential for prospective hydrologists. Individuals who have some experience with computer modeling, data analysis and integration, digital mapping, remote sensing, and Geographic Information Systems (GIS) will be the most prepared to enter the job market. Familiarity with the Global Positioning System (GPS)—a locator system that uses satellites—is vital.