This unit is an introduction to hydrological science which emphasises issues such as climate, groundwater and water quality. Topics covered include: influence of land masses and ocean current/temperature/pressures; the atmosphere; global circulation; precipitation; nature and impact of El Nino; worldwide climate trends; causes and nature of climate change; Manning's equation for channel flow; hydrological cycle; runoff and stream flow; types of aquifer; extremes of floods and droughts; probability distributions: Gumbel, Chow methods and analysis; water chemistry; salinity: occurrence, distribution and mitigation.