Hydrology is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and drainage basin sustainability. A practitioner of hydrology is called a hydrologist. Hydrologists are scientists studying earth or environmental science, civil or environmental engineering, and physical geography. Using various analytical methods and scientific techniques, they collect and analyze data to help solve water related problems such as environmental preservation, natural disasters, and water management.
A flood is an overflow of water that submerges land that is usually dry. In the sense of "flowing water", the word may also be applied to the inflow of the tide. Floods are of significant concern in agriculture, civil engineering and public health. Human changes to the environment often increase the intensity and frequency of flooding. Examples for human changes are land use changes such as deforestation and removal of wetlands, changes in waterway course or flood controls such as with levees. Global environmental issues also influence causes of floods, namely climate change which causes an intensification of the water cycle and sea level rise. For example, climate change makes extreme weather events more frequent and stronger. This leads to more intense floods and increased flood risk.
A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high discharge. The soils usually consist of clays, silts, sands, and gravels deposited during floods.
Hydrometeorology is a branch of meteorology and hydrology that studies the transfer of water and energy between the land surface and the lower atmosphere for academic research, commercial gain or operational forecasting purposes.
Rafael Luis Bras is a Puerto Rican civil engineer best known for his contributions in surface hydrology and hydrometeorology, including his work in soil-vegetation-atmosphere system modeling.
Snowpack is an accumulation of snow that compresses with time and melts seasonally, often at high elevation or high latitude. Snowpacks are an important water resource that feed streams and rivers as they melt, sometimes leading to flooding. Snowpacks provide water to down-slope communities for drinking and agriculture. High-latitude or high-elevation snowpacks contribute mass to glaciers in their accumulation zones, where annual snow deposition exceeds annual melting.
The Surface Water and Ocean Topography (SWOT) mission is a satellite altimeter jointly developed and operated by NASA and CNES, the French space agency, in partnership with the Canadian Space Agency (CSA) and UK Space Agency (UKSA). The objectives of the mission are to make the first global survey of the Earth's surface water, to observe the fine details of the ocean surface topography, and to measure how terrestrial surface water bodies change over time.
Flood control methods are used to reduce or prevent the detrimental effects of flood waters. Flooding can be caused by a mix of both natural processes, such as extreme weather upstream, and human changes to waterbodies and runoff. Flood control methods can be either of the structural type and of the non-structural type. Structural methods hold back floodwaters physically, while non-structural methods do not. Building hard infrastructure to prevent flooding, such as flood walls, is effective at managing flooding. However, best practice within landscape engineering is more and more to rely on soft infrastructure and natural systems, such as marshes and flood plains, for handling the increase in water.
The aim of water security is to make the most of water's benefits for humans and ecosystems. The second aim is to limit the risks of destructive impacts of water to an acceptable level. These risks include for example too much water (flood), too little water or poor quality (polluted) water. People who live with a high level of water security always have access to "an acceptable quantity and quality of water for health, livelihoods and production". For example, access to water, sanitation and hygiene services is one part of water security. Some organizations use the term water security more narrowly for water supply aspects only.
Coastal flooding occurs when dry and low-lying land is submerged (flooded) by seawater. The range of a coastal flooding is a result of the elevation of floodwater that penetrates the inland which is controlled by the topography of the coastal land exposed to flooding. The seawater can flood the land via several different paths: direct flooding, overtopping or breaching of a barrier. Coastal flooding is largely a natural event. Due to the effects of climate change and an increase in the population living in coastal areas, the damage caused by coastal flood events has intensified and more people are being affected.
The Flood Forecasting Centre (FFC) is a joint venture between the Environment Agency and the Met Office to provide improved flood risk guidance for England and Wales. The FFC is based in the Operations Centre at the Met Office headquarters in Exeter and is jointly staffed from both organisations.
Socio-hydrology; socio and hydrology is an interdisciplinary field studying the dynamic interactions and feedbacks between water and people. Areas of research in socio-hydrology include the historical study of the interplay between hydrological and social processes, comparative analysis of the co-evolution and self-organization of human and water systems in different cultures, and process-based modelling of coupled human-water systems. The first approach to socio-hydrology was the term "hydro-sociology", which arises from a concern about the scale of impact of human activities on the hydrological cycle. Socio-hydrology is defined as the humans-water interaction and later as “the science of people and water”, which introduces bidirectional feedbacks between human–water systems, differentiating it from other related disciplines that deal with water. Furthermore, socio-hydrology has been presented as one of the most relevant challenges for the Anthropocene, in relationship with its aims at unraveling dynamic cross-scale interactions and feedbacks between natural and human processes that give rise to many water sustainability challenges. Socio‐hydrology is also predicted to be an important license for modellers.
Keith John Beven is a British hydrologist and distinguished emeritus professor in hydrology at Lancaster University. According to Lancaster University he is the most highly cited hydrologist.
James Hall, is Professor of Climate and Environmental Risks and former director of the Environmental Change Institute at the University of Oxford. He is director of research at the School of Geography and the Environment, Senior Research Fellow at the Department of Engineering Science and Fellow of Linacre College. Hall is a member of the UK Prime Minister's Council for Science and Technology, commissioner of the National Infrastructure Commission, and is chair of the Science and Advisory Committee of the International Institute for Applied Systems Analysis. He was appointed as a Fellow of the Royal Academy of Engineering in 2010. He was a member of the Adaptation Sub-Committee of the UK Climate Change Committee from 2009 to 2019. He was appointed as vice-president of the Institution of Civil Engineers in 2021 with a view to become president in 2024.
Amir AghaKouchak is an Iranian American civil engineer, academic and researcher. He is a Professor of Civil Engineering, Environmental Engineering, and Earth System Science at University of California, Irvine.
Giuliano Di Baldassarre is a professor of hydrology at Uppsala University and the Director of the Centre of Natural Hazards and Disaster Science, Sweden. He was awarded the American Geophysical Union Whiterspoon Lecture in 2020 and the European Geosciences Union Plinius Medal in 2021.
Urban flooding is the inundation of land or property in cities or other built environment, caused by rainfall or coastal storm surges overwhelming the capacity of drainage systems, such as storm sewers. Urban flooding can occur regardless of whether or not affected communities are located within designated floodplains or near any body of water. It is triggered for example by an overflow of rivers and lakes, flash flooding or snowmelt. During the flood, stormwater or water released from damaged water mains may accumulate on property and in public rights-of-way. It can seep through building walls and floors, or backup into buildings through sewer pipes, cellars, toilets and sinks.
Upmanu Lall is an Indian-American engineer and founding director of the Water Institute at the Julie Ann Wrigley Global Futures Laboratory at Arizona State University. Lall also has a faculty appointment as professor in the School of Complex Adaptive Systems within the College of Global Futures. Prior to joining ASU in January 2024, Lall was the Alan and Carol Silberstein Professor of Engineering at Columbia University. He served as founding director of the Columbia Water Center. Lall studies how to solve water scarcity and how to predict and mitigate floods. In 2014, he was awarded the Henry Darcy Medal by the European Geosciences Union. He was named an American Geophysical Union Fellow in 2017 and their Walter Langbein Lecturer in 2022. He was elected a fellow of the American Association for the Advancement of Science in 2018, and has received the Arid Lands Hydrology and the Ven Te Chow Awards from the American Society of Civil Engineers. In April 2021 he was named to the “Hot List of the world’s 1,000 top climate scientists” by Reuters.
Canada contains the most lakes in the world, with nearly 900,000 lakes covering more than 10 hectares. This abundance is due to Canada's glacial history, with the vast majority of the country covered by a massive ice sheet during the last ice age. Canadian lakes represent approximately 62% of the world's 1.42 million lakes. Lake levels influence many aspects of our lives, such as water resource management, and environmental sustainability. Water levels in lakes are highly susceptible to climatic fluctuations, which have a significant impact on both the volume and purity of available water resources, as well as the ecological health of the watershed. Accurate lake level predictions have therefore become critical for effective water resource management in an era of increasing climate variability and changing hydrological patterns. Indeed, water levels in lakes are highly susceptible to climatic fluctuations, which have a significant impact on both the volume and purity of available water resources, as well as the ecological health of the watershed. The expected increase in both the frequency and intensity of extreme weather events may threaten the natural quality of water, emphasising the critical need for well-planned strategies for managing water resources and maintaining water quality.
