Hydrologists use math and science to solve water-related problems in society. Their work can include finding water supplies for cities and irrigated farms, controlling river flooding or soil erosion, or preventing and cleaning up pollution. They may spend a lot of time doing fieldwork in remote locations, and they rely heavily on computers for analyzing the data they collect. The work of hydrologists is extremely varied and range from planning multi-million dollar interstate water projects to advising homeowners about backyard drainage problems.