Floods

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Flooding is the most common and costliest natural hazard facing the United States. Over the last 30 years, floods have caused an average of $8 billion in damages and 82 deaths per year nationwide.

Basics

A flooded farm field. Image Copyright © Michael Collier. http://www.earthscienceworld.org/images

Flooding has many causes, including heavy rain, snow melting too fast, and dams or levees breaking. Coastal flooding occurs during hurricanes from heavy rainfall and storm surge, which causes sea level to rise temporarily at the shore.   Read more

Frequently Asked Questions

National Oceanic and Atmospheric Administration
U.S. Geological Survey
American Geosciences Institute

Latest News

Mammatus clouds that are usually associated with thunderstorms.
(2017-12-13)
November 14, 2017 Following months of debate on the floor continuing late in the day on November 14, the House of Representatives passed legislation that would reauthorize the National Flood Insurance Program (NFIP) for five more years, while making several operational changes. According to the...
NASA hurricane satellite image
(2017-09-14)
August 29, 2017 In anticipation of Hurricane Harvey making landfall on the Gulf Coast, the U.S. Geological Survey (USGS), National Oceanic and Atmospheric Administration (NOAA), and National Aeronautics and Space Administration (NASA) were preparing for the massive storm by monitoring its...
NASA hurricane satellite image
(2017-05-18)
April 18, 2017 The Weather Research and Forecasting Innovation Act (H.R.353) was signed into law by President Trump on April 18. This law prioritizes U.S. leadership in weather forecasting and research by authorizing new forecasting programs and support existing programs. The bill primarily focuses...
Flooding webinar postcard. Image Credit: AGI
(2017-02-07)
Join hundreds of attendees from around the world for an in-depth discussion on assessing, mitigating, and communicating flood risk tomorrow, Wednesday, February 8, 2017 at 1:00pm EST. Register here. More info below.   This webinar features experts from federal and state government, who will...
Screenshot of the Marine Cadastre National Viewer. Image Credit: NOAA, BOEM
(2016-09-30)
The American Meteorological Society (AMS) Policy Program’s workshop, “Opportunities and Needs in Integrated Water Prediction, Risk Assessment, and Management for Coastal Resilience,” concluded on September 28th, providing insights to coastal scientists and managers on how to better serve their...
Screenshot of the USGS Coastal Change Hazards Portal map
(2016-09-29)
On September 27th and 28th, our Critical Issues intern attended a workshop hosted by the American Meteorological Society (AMS) Policy Program: “Opportunities and Needs in Integrated Water Prediction, Risk Assessment, and Management for Coastal Resilience.” The first day focused on resilience issues...
Interactive map of Texas Gulf shoreline change rates. Image Credit: Bureau of Economic Geology, University of Texas
(2016-09-23)
#MapOfTheDay! Today the Critical Issues Program (@AGI_GeoIssues) shared an interactive map of shoreline change rates along the Texas Gulf Coast from the Bureau of Economic Geology at the University of Texas Jackson School of Geosciences (@txgeosciences), which you can find at http://bit.ly/1GoF214...
August 2016 Statewide Precipitation Ranks. Image Credit: NOAA
(2016-09-21)
The National Oceanic and Atmospheric Administration (NOAA) held their latest Monthly Climate Briefing on September 15, 2016, and we have summarized the highlights for you below: •  August 2016 is the 17th warmest (73.6°F, 1.5°F above average), 2nd wettest August (3.47", 0.85" above average) since...
NASA hurricane satellite image
(2016-08-25)
August 16, 2016 The National Oceanic and Atmospheric Administration (NOAA) recently launched its National Water Model (NWM), a new hydrologic model that the agency claims will yield the “biggest improvement in flood forecasting the country has ever seen.” The new model will allow NOAA’s National...
(2016-06-09)
AGI's Geoscience Policy Program published the May 2016 Summary of federal-level legislation impacting the geoscience community. This includes continuing appropriations discussions in both the House and Senate for funding in FY 2017 for agencies that employ geoscientists, studying geoscience...

Case Studies & Factsheets

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Introduction Dry wells improve stormwater drainage and aquifer recharge by providing a fast, direct route for rainwater to drain deep into underlying sediment and rock. Dry wells are most common in the western U.S. where clay or caliche layers slow down the natural drainage of water into...

CI_Factsheet_2017_4_drywellbasics_170906_thumb.JPG

What is a Dry Well? A dry well is a well that is used to transmit surface water underground and is deeper than its width at the surface (see image, below). Most dry wells are 30 to 70 feet deep and 3 feet wide at the surface. They are lined with perforated casings and can be filled with gravel...

Pre-Ike (left) and post-Ike (right) ASTER imagery of Galveston Island, the Bolívar Peninsula, and the mainland in August 2006. Healthy (red) and dead (brown) vegetation shows storm surge inundation effects. Image Credit: Jesse Allen, NASA Earth Observ.

Defining the Problem Hurricanes bring not only intense rainfall, but also high winds and flooding. This flooding is powered by the hurricane storm surge: a rise in coastal sea level caused by lowered barometric pressure and by wind blowing the ocean onto the land. The result is that waves and...

GOLI Online Courses

GOLI Course: Planning for Coastal Storm and Erosion Hazards; Image credit: USGS/USFWS - photo by Greg Thompson
Course Type: GOLI Online Course

Coastal hazards are a widespread challenge that cost millions (and sometimes billions) of dollars in the U.S. every year due to property loss and spending on mitigation measures. Based on the most recent U.S. Census, over 39% of the U.S. population lives in areas that may undergo significant...

GOLI Course: Assessing, Mitigating, and Communicating Flood Risk. Image courtesy of Maria Coxx Lamm
Course Type: GOLI Online Course

Flooding is a perennial hazard for rivers and coasts alike. Every year, flooding results in billions of dollars of damage and the loss of dozens to hundreds of lives across the United States. Efforts to mitigate this hazard rely on the work of geoscientists, planners, and communicators to assess...

Research Database Publications

Cover for USGS FS 2013-3108 ; Source: USGS
2014, U.S. Geological Survey (USGS)
Flood-frequency analysis provides information about the magnitude and frequency of flood discharges based on records of annual maximum instantaneous peak discharges collected at streamgages. The information is essential for defining flood-hazard areas, for managing floodplains, and for designing...
Cover of fs2016-3026 ; Image credit: U.S. Geological Survey
2016, U.S. Geological Survey (USGS)
Urban development creates multiple stressors that can degrade stream ecosystems by changing stream hydrology, water quality, and physical habitat. Contaminants, habitat destruction, and increasing streamflow variability resulting from urban development have been associated with the disruption of...
Cover of fs2016-3024 ; Image credit: U.S. Geological Survey
2016, U.S. Geological Survey (USGS)
Streams and estuaries with urban watersheds commonly exhibit increased streamflow and decreased base flow; diminished stream-channel stability; excessive amounts of contaminants such as pesticides, metals, industrial and municipal waste, and combustion products; and alterations to biotic community...
Cover of PP1821: Source: USGS
2015, U.S. Geological Survey (USGS)
Flooding in the Northeastern United States during 2011 was widespread and record setting. This report summarizes peak streamflows that were recorded by the U.S. Geological Survey (USGS) during separate flooding events in February, March, April, May, July, August, and September. The flooding of late...
Cover of sir20165118; Image credit: U.S. Geological Survey
2016, U.S. Geological Survey (USGS)
An investigation into the magnitude and frequency of floods in Washington State computed the annual exceedance probability (AEP) statistics for 649 U.S. Geological Survey unregulated streamgages in and near the borders of Washington using the recorded annual peak flows through water year 2014. This...
Cover of Flooding factsheet; Image credit: The Geological Society
2016, The Geological Society of London (GSL)
How many types of flood are there? Why does flooding happen, and how can we protect ourselves? This fact sheet, produced for a broad general audience, gives an overview of flooding categories, and how we can mitigate their effects.
Cover of USGS_2015-1204; Source: U.S. Geological Survey
2015, U.S. Geological Survey (USGS)
In the Pacific Northwest, coastal wetlands support a wealth of ecosystem services including habitat provision for wildlife and fisheries and flood protection. The tidal marshes, mudflats, and shallow bays of coastal estuaries link marine, freshwater, and terrestrial habitats, and provide economic...
Cover of fs2016-3008; Source: U.S. Geological Survey
2016, U.S. Geological Survey (USGS)
The U.S. Geological Survey (USGS) has many ongoing and recent water-related natural hazard activities in New England that can be used to help mitigate the effects of natural hazards in cooperation with other agencies. The themes related to potential hazards and the tools and science to better...
Cover of fs2016-3073; Image credit: U.S. Geological Survey
2016, U.S. Geological Survey (USGS)
The Souris River Basin is a 61,000 square kilometer basin in the provinces of Saskatchewan and Manitoba and the state of North Dakota. Record setting rains in May and June of 2011 led to record flooding with peak annual streamflow values (762 cubic meters per second [m3/s]) more than twice that of...
Cover of SIR2015-5065; Source: U.S. Geological Survey
2015, U.S. Geological Survey (USGS)
The U.S. Geological Survey, in cooperation with the Puerto Rico Electric Power Authority, completed a hydrologic and hydraulic study to assess the potential hazard to human life and property associated with the hypothetical failure of the Lago de Matrullas Dam, located within the headwaters of the...