Flood Information and Data
For more than 100 years, the USGS has played a critical role in reducing flood losses by operating a nationwide streamgage network that monitors the water level and flow of the Nation’s rivers and streams. Through satellite and computer technology, streamgages transmit real-time information, which the National Weather Service (NWS) uses to issue flood warnings. Streamgages provide long-term data that scientists need to better understand floods and to define flood-prone areas as well. Streamgage data also help in designing structures resilient to flooding and are the basis for the Federal Emergency Management Agency’s (FEMA) National Flood Insurance program, the only Federal insurance program for natural hazards.
- Carson River Flood Chronology: This NVWSC web site makes historic flood information publicly available. The focus of the Carson River web site is on existing data, both measured and estimated for flood events prior to streamflow monitoring. Data includes historic flood photography, video clips, flood-frequency analyses, associated climatology, flood narratives, and links to other flood-related web sites.
- Mapping a flood...Before it happens: USGS and NWS have developed a way to bring flood forecasting and flood mapping together, producing flood maps for tomorrow's flood today...and getting them on the Internet in time for those in harm's way to react.
- FEMA Flood Map Service Center: This web site allows the general public to search for FEMA maps to determine if a property is in a flood hazard area.
- NWS Flood Information: NWS provides several hydrology products for determining conditions in a specific area.
- USGS Information on El Nino: A collection of web sites about El Nino and its effects: floods, landslides, coastal hazards, and climate.
- Large floods in the United States: Where they happen and why: This circular summarizes the locations and magnitudes of large flows recorded by these gaging stations, showing locations in the United States where relatively large floods occur, and describes, in general terms, some of the climatologic and topographic factors that contribute to large floods.
- 100-Year Floods--It's All about Chance: This USGS poster explains what a 100-year flood is, and what it isn't, in layman's terms.
USGS Scientists Hartley Delvalle and Connor Murphy measured surface velocity of 25 feet per second using a radar gun at USGS gaging station 09419745 C-1 Channel above mouth near Henderson, NV, during August 12, 2015, flash flooding in southern Nevada. Preliminary estimated peak flow from August 12 at this site is a new record at 3,340 cubic feet per second!
WaterWatch is a national USGS web site that provides streamgage-based maps that show the location of more than 3,000 long-term (30 years or more) USGS streamgages; use colors to represent streamflow conditions compared to historical streamflow; feature a point-and-click interface allowing users to retrieve graphs of stream stage (water elevation) and flow; and highlight locations where extreme hydrologic events, such as floods and droughts, are occurring
One of the tools from the site is the flood-tracking chart builder. This site will build a chart of current stage, recent maximum stage, highest recorded peak stages, and National Weather Service flood stage for any USGS gaging station.