Looking east at Burdick Expressway as the Souris River rises in Minot, North Dakota. Photo taken by USGS personnel during a FEMA Flood Inundation Mapping Project.

Throughout the last century in the United States, on average, floods have caused more lives lost and more economic damage than any other natural hazard. According to forecasts, severe flooding in 2012 will likely be far less widespread than last year. However, scientists cannot predict weather and water patterns with 100 percent accuracy, and there is always the potential for severe flooding somewhere in the country.

When it comes to flooding, preparation is key for saving lives and protecting property. USGS scientists and hydrologic technicians are specially trained and standing by. As soon as water starts to rise, they are measuring water levels, river velocities, and high water marks. All of this information is crucial for National Weather Service flood forecasts, for decisions by the U.S. Army Corps of Engineers to operate spillways and levees, and for the planning of Federal, State, and local emergency managers, first responders, and many other groups.

In preparation for flood events, the USGS continues to invest in and update equipment like the acoustic Doppler current profiler, which measures water velocity, as well as rapidly deployable streamgages, which measure river heights in areas that do not have a permanent gage or where a gage has been damaged by fast-moving water.

Perhaps most importantly, the USGS is constantly refining, innovating, and updating its ability to deliver river information to emergency managers, first responders, and other Federal agencies before, during, and after a flood. The USGS offers an increasing number of resources to help these organizations, as well as you and your family, better prepare for flood hazards.

Flood Inundation Mapping

When the water starts to rise, how do you know if you’re going to get wet?

Right now, if you want to see areas where river levels are higher than normal, you can go to USGS WaterWatch and view a map of the thousands of real-time streamgages that constantly monitor the Nation’s rivers and streams. But how do you put that number in context? If the current stage is forecasted to go above flood stage, does that mean water will be barely spilling over the banks? Or does it mean that your house might be underwater? At what stage is the river going to spill over onto a roadway and affect traffic? Are you and your family in danger?

River stage measurements can be confusing, and they are not always a great indicator of the actual scope and impacts of the flooding. To reduce this ambiguity, the USGS and the National Weather Service are working together to create visual products, called flood inundation map libraries, that show you estimates of where the water will be — what roads, yards, and buildings will be affected — when a river or stream reaches a certain stage.

For example, in Findlay, Ohio, the flood inundation map shows that when the stream stage is around 11 feet, only the roads closest to the river are underwater, but the rest of the town is out of danger. However, when you use the tool to map out a flood stage of 18 feet, streets as far as 15 blocks away from the river’s banks are underwater, as are a few parks, a cemetery, and almost the entire Findlay Country Club.

A powerful new tool for flood response and mitigation are digital geospatial flood-inundation maps that show flood water extent and depth on the land surface. Because floods are the leading cause of natural-disaster losses, the U.S. Geological Survey (USGS) is actively involved in the development of flood inundation mapping across the Nation pursuant to its major science strategy goal of reducing the vulnerability of the people and areas most at risk from natural hazards. Flood inundation maps have been created for cities on the map indicated by a black triangle (Iowa City, IA, Marshall, MI, Ottawa, OH, Findlay, OH, Peach Creek, near Atlanta, GA, Albany, GA, Trenton, NJ St. John River, near Fort Kent, ME, and Scituate, MA).

In Iowa City, Iowa, the flood inundation map shows that when the stream stage is at 17 feet, the river is barely out of the channel, and most of the town is out of danger. But when you map out a flood stage of 25 feet, parks and local areas designed to hold floodwaters are submerged. At 30 feet, several neighborhoods and much of the University of Iowa are flooded. On this map, you can click anywhere in the flooded area to see the estimated water depth for any location at any stage. Damage estimation models, which are based on FEMA’s Hazus tool, are also available for each flood stage on the map. All of these features allow emergency managers to see what areas and how many people need to be evacuated, and to estimate the cost of potential flood damages.

This new tool is especially useful to emergency managers responsible for keeping people safe on the roads. In fact, over half of all flood-related deaths are the result of people driving their cars onto submerged roadways. These new, interactive flood maps allow emergency managers to see what roads will be submerged at a forecasted flood level, so that the roads can be closed long before waters start to rise.

Flood inundation maps have already been produced for nine areas in the United States. The USGS plans to produce over 40 more of these maps within the next year, including for Terra Haute, Ind., Sweetwater Creek, Ga., and Hattiesburg, Miss. The USGS hopes to eventually have flood inundation map libraries available for many other areas across the country.

You can see what areas have already been mapped by using the tool.

WaterAlert

Smartphones let you know when the river is rising

If you’re on the USGS site and reading this, chances are you probably have a favorite outdoor spot, a favorite river, and perhaps a favorite streamgage that you check on a regular basis. Did you know that you can get automatic notifications from that streamgage sent straight to you as an email or text message? The USGS provides a service called WaterAlert that can text or email you when water levels at a streamgage of interest exceed certain thresholds.

This means that you can keep tabs on a river without having to repeatedly check the USGS website. And if waters start to suddenly rise, you will be alerted, allowing you to put necessary precautions in place to keep yourself, your family, and your property safe.

USGS scientists take streamflow and water quality measurements downstream of the Bonnet Carre Spillway near Norco, La. The Army Corps of Engineers uses USGS streamflow data to help them manage flood control structures.

Sign up for WaterAlert by selecting a State, checking the “surface water” box, and clicking on your streamgage of choice. You can also subscribe to WaterAlert from the flood inundation interactive map. If you live in a community covered by a flood inundation library, use the flood inundation map to discover what flood stage puts you at risk, then click the link in the “Services and Data tab” to sign up to receive a text or email when the water approaches, reaches, or exceeds that stage!

Links:

Flood Inundation Interactive Mapper: http://wim.usgs.gov/FIMI/FloodInundationMapper.html

Additional information about Flood Inundation Mapping: http://water.usgs.gov/osw/flood_inundation/

WaterAlert: http://water.usgs.gov/wateralert/

Main USGS Flood Site: http://water.usgs.gov/floods

News Release: Smart Phones Know When Rivers Rise…with USGS WaterAlert: http://www.usgs.gov/newsroom/article.asp?ID=2919

News Release: Instant Information about Water Conditions: Ask the River to Text You a WaterAlert: http://www.usgs.gov/newsroom/article.asp?ID=2464

Yet because groundwater is a hidden resource lying below the land surface, it suffers from “out of sight, out of mind” syndrome. People often overlook it, underappreciate it, take it for granted.

Unseen and easily neglected, it’s no less important. How much groundwater is available in your neighborhood? What quantities of withdrawal by a new industry or a growing number of new neighbors could be sustained? What about the quality of the groundwater?

USGS Science Making Connections

Example of wellhead plumbing typical of public wells sampled in a USGS study of 932 public wells nationwide. About 105 million people—or more than one-third of the Nation's population—receive their drinking water from one of the 140,000 public water systems across the United States that rely on groundwater pumped from public wells. The USGS studies source (untreated) water collected from public wells before treatment or blending, which often are used by public water systems to decrease contaminant concentrations below levels of potential human-health concern. These types of studies assist water utility managers and regulators in making decisions about future monitoring needs and drinking-water issues. Michael Rosen, USGS.

Understanding the connections between ground and surface water as part of the hydrologic cycle is crucial to successfully managing water resources. Surface water ends up below the surface as groundwater when rain and collected water seep into the ground. Then groundwater flows within an underground aquifer. Later, it discharges at the surface again to a spring, stream, lake, or other surface water body. USGS scientists, in collaboration with federal, state, and local partners are working to better understand how groundwater flow is affected by population, changes in land use, and ecological demands.

Many USGS studies about groundwater availability are local in scope, simply because local studies are crucial for managing this resource on a local level. However, because local groundwater is interconnected with other components of the hydrologic system, including other parts of aquifers and surface water, it is also important to consider the entire aquifer when assessing groundwater availability.

The goal of the USGS GroundwaterResourcesProgram is to document groundwater availability in all of the majoraquifers in the United States. These studies will quantify current aquifer resources, provide a means to evaluate how these resources have changed over time, and provide tools to forecast how much water will be available in the future.

The USGS develops models to understand the interactions between groundwater and surface water. Last year, USGS scientists developed a model for theYakimaBasin in Washington State that will help regulators understand how surface water and groundwater are interconnected. Similar studies are being planned or underway throughout the country through the USGS CooperativeWaterprogram.

USGS researchers are also studying the effect that climate change will have on groundwater.  Climatechange, for example, will affect snowpack, precipitation, water vapor, soil temperature, soil moisture and other aspects of the hydrologic cycle, all of which will also affect groundwater availability.

Great Lakes water availability studies conducted by the U.S. Geological Survey aim to help characterize how much water the Basin has now, how water availability is changing, and how much water it can expect to have in the future.

Groundwater use is also affecting  ouroceansandcoasts through sea level rise. Once water is pumped out of the aquifer system, it doesn’t always go back in at the same rate. This means that excess water (runoff) ends up on the surface and ultimately in the ocean. Groundwater development has significantly increased in the past 50 years, and USGS scientists have found that this increase in use has exacerbated the effects of sea level rise.

Because we depend on high-quality, fresh water — not only for health, but for many industrial and energy uses — groundwater availability is also linked to water quality.  The USGS National Water Quality Program is documenting water quality in the principle aquifers throughout the country while continuing studies to determine which groundwater sources are most vulnerable to contaminants like arsenic, radium, and other trace elements.

National Groundwater Awareness Week

March 11-18, 2012 is the National Groundwater Association’s NationalGroundwaterAwarenessWeek. Learn more about what you can do to protect your groundwater from the NationalGroundwaterAssociation or the U.S. EnvironmentalProtectionAgency.