USGS Newsroom

New Insight on Gas Hydrates in Gulf of Mexico

OC_Web@usgs.gov (Office of Communications and Publishing) — Tue, 14 May 2013 10:00:00 EDT

Research is Part of a Long-Standing, Interagency Collaboration

Scientists have returned from a 15‑day research expedition in the northern Gulf of Mexico with the best high-resolution seismic data and imagery ever obtained of sediments with high gas hydrate saturations.

The expedition and the data and imagery collected resulted from long-standing cooperation between the U.S. Department of the Interior's U.S. Geological Survey (USGS) and Bureau of Ocean Energy Management (BOEM) and the U.S. Department of Energy (DOE). This collaboration aims to advance scientific understanding of gas hydrates, an important potential future energy resource.

Gas hydrates are ice-like substances formed when certain gases combine with water at specific pressures and temperatures. Deposits of gas hydrates are widespread in marine sediments beneath the ocean floor and in sediments within and beneath permafrost areas, where pressure-temperature conditions keep the gas trapped in the hydrate structure. Methane is the gas most often trapped in these deposits, making gas hydrates a potentially significant source for natural gas around the world.

"This expedition represents a significant milestone," said USGS Energy Resources Program Coordinator Brenda Pierce. "The data and imagery provide insight into the entire petroleum system at each location, including the source of gas, the migration pathways for the gas, the distribution of hydrate-bearing sediments, and the traps that hold the hydrate and free gas in place. The USGS has a globally recognized research effort studying gas hydrates in settings around the world, and this project combines our unique expertise with that of other agencies to advance research on this potential future energy resource."

The recently completed expedition was planned jointly by USGS, DOE, and BOEM, and was executed by USGS. Using low-energy seismic sources, USGS scientists collected details about the nature of the gas hydrate reservoirs and about geologic features of the sediment between the reservoirs and the seafloor. The new data also provide information about how much gas hydrate exists in a much broader area than can be determined from using standard industry seismic data, which is typically designed to image much deeper geologic units.

"Understanding the nature and setting of deepwater gas hydrates is central to the National Methane Hydrates R&D Program, which is led by DOE and managed by Fossil Energy's National Energy Technology Laboratory," said Christopher Smith, DOE’s Acting Assistant Secretary for Fossil Energy. "Over the past 8 years, research carried out under this program has resulted in significant advances in our understanding of methane hydrates, their role in nature, and their potential as a future energy resource. This success is largely due to an unprecedented level of cooperation among federal agencies, industry, national laboratories, and academic institutions."

"The high-resolution nature of the data acquired through this interagency project will uniquely inform the BOEM effort to assess the resource potential of gas hydrates on the U.S. Outer Continental Shelf," said Renee Orr, Chief, Strategic Resources Office, BOEM.

The data were collected at two locations in the Gulf of Mexico where the three federal agencies partnered with an industry consortium to conduct a drilling expedition in 2009. That expedition discovered gas hydrate filling between 50 and 90 percent of the available pore space between sediment grains in sandy layers in the subsurface. These reservoirs are expected to be representative of the 6,700 trillion cubic feet of gas that BOEM estimates is housed in gas hydrates in sand-rich reservoirs in the northern Gulf of Mexico.

The new data are being used to refine estimates of the nature, distribution, and concentration of gas hydrate in the vicinity of the 2009 drill sites. This will help assess how useful specialized seismic data may be to estimating hydrate saturations in deepwater sediments.

In coming years, the three agencies will continue their collaborative investigation of gas hydrates in the northern Gulf of Mexico and other locations across the world.

Learn more about USGS research on gas hydrates and energy at locations around the world.

Stars show the locations of seismic surveys conducted to image previously-identified deepwater gas hydrate deposits in the northern Gulf of Mexico on the research ship Pelican during a cruise in April and May 2013. (Larger image)

This high-resolution image was collected during a seismic cruise to study locations with high concentrations of gas hydrate in the northern Gulf of Mexico in April and May 2013. The data were collected at the Walker Ridge location, where 2009 drilling at the site of the well (shown in red revealed) the distribution of gas hydrates and methane gas in the sediments. The water depth at the well is 6562 feet, and the red and blue colors shown within the image correspond to sediment layers, which mostly dip westward. Sand layers with high concentrations of gas hydrate are marked, but hydrate also occurs elsewhere in this sedimentary section. (Larger image)

New Map Tool Helps Prepare Hattiesburg for Floods

OC_Web@usgs.gov (Office of Communications and Publishing) — Thu, 8 Nov 2012 10:06:53 EDT

First-of-its-Kind in State

HATTIESBURG - Miss. – A dynamic new online flood preparedness tool that will help emergency managers improve flood warnings and response has been developed for the Leaf River, site of the historic flood that devastated portions of Hattiesburg in 1974 and led to eight deaths.

The interactive web-based tool, called a "flood inundation map," was created by scientists from the U.S. Geological Survey. The map will help identify where the potential threat of floodwaters is greatest, providing key information to the Federal Emergency Management Agency and state and local officials to help them make quick decisions about when and how to evacuate residents threatened by rising floodwaters. State and local emergency managers will be able to use the interactive tool to better focus flood response and resource recovery and to swiftly assess evacuation routes.

"Back in '74, there was no world-wide web for posting up-to-date emergency content, nor smart phones or PCs for delivering that content to citizens in harms way," said USGS Director Marcia McNutt, "Thanks to exceptional cooperation between relevant government agencies, we can now harness modern technology to seamlessly deliver useful information in a convenient and understandable format, turning potential victims into savvy survivors."

The USGS is partnering with the National Weather Service, United States Army Corps of Engineers and FEMA to develop comparable flood inundation maps in locations across the country identified to be at the highest risk for flooding. The Forrest County Emergency Management District lined up local partners to fund the Hattiesburg project, including the Cities of Hattiesburg and Petal, Forrest County, Mississippi Department of Homeland Security, and the Mississippi Emergency Management Agency.

"Flooding is an extremely serious situation that can not only cause massive property damage but is also a threat for loss of life," said Terry Steed, executive director of the Forrest County Emergency Management District. "This inundation map will provide the public with necessary information to prepare for and take action to mitigate the effects of a major flood. Major flood events are life changing for those who are in its path, however, preparation and mitigation helps to lessen those effects."

More than 6,000 people were evacuated from Hattiesburg and surrounding communities during the flooding in 1974. Mickey Plunkett, the Director of the USGS Mississippi Water Science Center, had his first experience with Hattiesburg's flood history in April of 1974 as a cooperative education student with the USGS Center. "I was a member of the crew that measured the peak flow at Hattiesburg during the 1974 flood. That flood still holds the record as the highest flood since records began in 1904,” said Plunkett.

The city's flood history, its location on the Leaf River and its potential to be impacted by tropical and subtropical rainfall events made it a top choice for development of the first flood inundation map in the state.

"As the fourth largest city in Mississippi, and one that sits directly on the banks of the Leaf River, Hattiesburg is in clear need of better tools to aid in flood planning and response," said John Storm, USGS hydrologist and lead author on the Leaf River flood inundation map. "We think this new tool will really fill that gap, and help emergency managers address future flood potential and response in any situation that comes up. It will also help the citizens to visualize the potential impact to their property from a forecasted flood stage and make appropriate decisions ahead of time."

The Flood Inundation Map is one of a series of flood preparedness tools that the USGS has developed to help emergency and resource managers and the public prepare for potential flooding and track water levels as they rise. The map is based on data from the USGS’s nationwide streamgage network that monitors the water level and flow of the nation's rivers and streams.

WaterAlert and StreaMail are two other online resources that provide residents with timely information about river conditions at important locations. Subscribers have a number of options to choose from on how to get the information, and can have emails or texts sent to them automatically whenever a critical threshold is reached. With these tools, emergency managers, resource managers and the public can stay informed and help keep themselves or others out of harm’s way by keeping up to date of local conditions.

The Leaf River flood inundation map is now available online.

USGS Helps Assess Tangipahoa Dam Health

OC_Web@usgs.gov (Office of Communications and Publishing) — Fri, 7 Sep 2012 14:08:42 EDT

JACKSON, Miss. – The U.S. Geological Survey mapped the damage caused to Tangipahoa Dam in 3-D earlier this week, using new technology to get a detailed view of the troubled dam. The dam was damaged during heavy rainfall in Hurricane Isaac and caused thousands of people downstream to be evacuated late last week.

Using terrestrial lidar, or T-lidar, the crew captured multiple scans of the dam, including two large landslides on its downstream side. In the larger of the two slides, much of the base of the slide was still underwater and necessitated the use of a kayak-towed acoustic Doppler profiler to measure the toe of the slide.

The first T-lidar scans took place Saturday, with more completed on Monday to assess whether additional movement of the slides had occurred. Monday's scan showed little change; information that has been provided along with other data to the U.S. Army Corps of Engineers as they continue to address the issue.

"We were fortunately already mobilizing this fabulous 3-D imaging technology when our field crews learned of the need to monitor the stability of the Tangipahoa Dam," said USGS Director Marcia McNutt. "I know of no other technology that could compete with T-lidar for providing both the precision and ease of deployment or that has the potential to determine whether a structure is in danger of failing when time is of the essence."

Isaac is the first storm in which USGS has used its terrestrial lidar capabilities to map urban flooding.

"We brought our T-lidar capabilities into the area affected by Isaac as part of a pilot project to assess its use for mapping flood levels in urban areas, and to develop flood inundation maps that will help forecast future flood effects," said Toby Minear, a research hydrologist at the USGS California Water Science Center, who completed the scans of the dam. "What we've found is that, not only can it help assess current flood levels and high-water marks, it has the potential to play a pivotal role in helping assess the health of structures threatened by floodwaters, providing critical information to those who need it in a matter of minutes."

T-lidar allows scientists to quickly generate 3-D maps of buildings, dams, levees and other structures, and can show areas of storm damage as well. In a four-to-five minute scan, the instrument collects millions of topographic data points in a full 360-degree view to quickly produce highly accurate topographic information and can map areas up to two-thirds of a mile away.

Acoustic Doppler instruments, such as the one used to map the underwater portion of the slide at Tangipahoa Dam, are frequently used to measure stream or lake geometry and water velocity. An acoustic signal is bounced off the river or lake bottom and the amount of time required for the signal to return to the sensor provides a measurement of the distance to the bottom.

USGS crews also deployed storm surge sensors just below the dam, and at four bridge crossings downstream between the dam and the USGS' real-time permanent streamgage on the Tangipahoa at Osyka. The sensors allowed the USGS to monitor river levels as actions were taken to release the pressure on the dam and reduce water levels.

3-D Mapping of Isaac Water Levels

OC_Web@usgs.gov (Office of Communications and Publishing) — Sat, 1 Sep 2012 11:34:38 EDT

3-D Mapping of Isaac Water Levels

A new technology is being deployed by U.S. Geological Survey scientists this weekend to map urban flooding caused by Hurricane Isaac. Called “terrestrial lidar,” or “T-lidar”, this new capability will enable scientists to collect highly detailed information in select population areas in Louisiana, Mississippi, and Alabama where the hurricane had the greatest impact.

The portable instrument allows scientists to quickly generate 3-D maps of buildings, dams, levees and other structures, and can show areas of storm damage as well. In a four-to-five minute scan, the instrument collects millions of topographic data points in a full 360-degree view to quickly produce highly accurate topographic information and can map areas up to two-thirds of a mile away.

The information gathered from this pilot project will be used by USGS to develop 3-D models of streets and structures, including the levels floodwaters reached, as well as current water levels in the form an interactive 3-D flood inundation map. The map will help identify where the potential threat of future floodwaters is greatest, and will help determine the extent of wind and flood damages caused by Isaac.

"If a picture paints a thousands words, a T-lidar scan paints several million words to capture the fleeting aftermath of a hurricane's impact," said USGS Director Marcia McNutt. "The ability to rapidly preserve for posterity a quantifiable, three-dimension representation of storm damage is going to open the doors for new flood hazard science."

T-lidar looks sideways from ground level, enabling it to capture vertical details, such as water levels, that airborne lidar cannot. This enables it to capture the extent of flooding. The USGS will be using both a tripod mounted and a truck-mounted version. While the tripod version takes individual scans from multiple locations that later have to be combined to develop its 3-D maps, the truck-mounted version is continuously collecting information that is available almost immediately.

"Using terrestrial lidar in this fashion has the possibility of helping us quickly assess high-water marks, current water levels, and to some degree flood damage, in a very short time," said Athena Clark, director of the USGS Alabama Water Science Center. "We’re always looking for better, more efficient and cost effective ways of advancing the science and this technology has some great possibilities."

"Lidar" stands for "light detection and ranging." Where "radar" uses radio waves as a form of measurement, "lidar" uses light. Terrestrial lidar, sometimes called “terrestrial laser scanning,” uses a sensor that emits laser pulses and measures distance by how long it takes the reflected laser beam to "bounce back" to the instrument. TLS can provide very precise data, to millimeter accuracy, to enable scientists to build high-resolution 3-D models of objects.

"We are collecting storm-tide information that will allow scientists to study the impacts of the storm in three dimensions," said Toby Minear, a research hydrologist at the USGS California Water Science Center, who is participating in the study. "Imagine a 360-degree panoramic photo, but made with laser points where everything you can see has a known elevation and location. These 'point clouds' can be put together to create a full 3-D map of an area containing many millions of data points."

In addition to the use of terrestrial lidar, the USGS is also planning airborne lidar flights to assess the level of coastal change caused by Isaac along the Gulf Coast. More information on both these studies will be released when they are completed.

Media Advisory: Measuring the Impact of Isaac

OC_Web@usgs.gov (Office of Communications and Publishing) — Thu, 30 Aug 2012 10:45:21 EDT

Media are invited to join U.S. Geological Survey crews working in areas impacted by Isaac as they retrieve storm-tide sensors deployed prior to the storm, measure high-water marks, make inland flood measurements, and collect water samples to measure water quality following the storm.

The storm-tide sensors will be retrieved from Mobile Bay in Alabama to Breton Sound in Louisiana, including Lake Pontchartrain. The sensors were installed to measure the storm-tide height and intensity of Hurricane Isaac. The information will help define the depth and duration of the storm-tide, as well as the time of its arrival and retreat. That information will help assess storm damage, discern between wind and flood damage, and improve computer models used to forecast future floods.

As Isaac moves inland, flooding from the drenching rains becomes an issue, and as the storm progresses northward, additional measurements will be required in the Midwest states.

What: Reporters can accompany the USGS crews as they retrieve the storm-tide sensors, measure high water marks, and collect water samples from various locations along the Gulf Coast. USGS crews will also be making flood measurements at affected streamgages inland from the coast that are critical for accurate flood forecasts.

Points of Contact:

• Louisiana:	George Arcement	(225) 978-4203
• Mississippi	Michael Plunkett	(601) 933-2940
• Alabama:	Athena Clark	(334) 395-4141

When/Where: The specific schedules and locations will vary by state depending on flooding and road closures. Contact the state point of contact for more information.

Additional information on USGS activities before, during and after the storm can be found on the USGS website.

Mississippi River Flows Backwards Due to Isaac

OC_Web@usgs.gov (Office of Communications and Publishing) — Wed, 29 Aug 2012 17:27:16 EDT

Strong winds and storm surge from Hurricane Isaac's landfall forced the Mississippi River to flow backwards for nearly 24 hours on Tuesday, August 28. The USGS streamgage at Belle Chasse, Louisiana, showed the Mississippi River flowing upstream at 182,000 cubic feet per second, surging to 10 feet above than its previous height. Average flow for the Mississippi River at Belle Chase is about 125,000 cfs towards the Gulf of Mexico.

Although it doesn't happen often, hurricanes can cause coastal rivers to reverse flow. Between the extremely strong winds and the massive waves of water pushed by those winds, rivers at regular or low flow are forced backwards until either the normal river-flow or the elevation of the land stop the inflow.

As Hurricane Isaac pushes further inland, it is causing storm surge in the Mississippi River as far north as Baton Rouge, where the river has crested at 8 feet above its prior height.

"This reversal of flow of the mighty Mississippi is but one measure of the extreme force of Isaac," said USGS Director Marcia McNutt. "While such events are ephemeral, they are yet another reminder of why we need to respect hurricane warnings."

When Hurricane Katrina came ashore in 2005, the Mississippi River also reversed flow, cresting at 13 feet above its previous level, with Baton Rouge reaching 9 feet above its previous stage as well.

Another phenomenon that USGS streamgages have recorded as Hurricane Isaac moves inland is that periodically, coastal rivers in Louisiana have lost height, only to gain it back again soon after. This rising and falling of the rivers is a common occurrence during hurricanes and is caused by the spiral nature of these storms.

As the winds sweep to the southwest, they force water out of the rivers, lowering their height. However, once the winds complete their turn to the southwest, they begin back to the northeast, allowing the storm surge to raise the river levels.

These oddities in river behavior are recorded in real-time by USGS' extensive network of streamgages, located through Louisiana and the rest of the country. These streamgages, which are installed along rivers and streams, record data like streamflow, river height, and, in some cases, even water chemistry.

Many transmit their data in real-time to satellites, updating with new information every 15 minutes. This wealth of data allows USGS scientists, emergency managers and responders, and even the general public to have accurate and up-to-date knowledge of what the rivers and streams in their areas are doing. This data is particularly critical during massive flooding events like Hurricane Isaac.

In fact, anyone can sign up to receive notices from USGS streamgages when waters are rising in nearby rivers and streams through a program called WaterAlert. It is a free service that allows members of the public to receive notifications about water levels at any of over 7,000 USGS real-time streamgages around the country. Learn more about how to sign up here.

All USGS streamgage information is housed online. For Hurricane Isaac, USGS has compiled a list of all streamgages in affected areas here.

For the latest forecasts on the storm, listen to NOAA radio. For information on preparing for the storm, visit Ready.gov or Listo.gov

This velocity hydrograph shows the velocity of the Mississippi River during Hurricane Isaac’s landfall. On August 28, the velocity begins to approach negative velocity as high winds and storm surge cause the river to reverse flow. By the end of August 28, the river had regained its regular flow. The USGS streamgage that recorded this information is located at Belle Chasse, LA.

USGS Storm-Surge Sensors Deployed Ahead of Isaac

OC_Web@usgs.gov (Office of Communications and Publishing) — Tue, 28 Aug 2012 17:59:21 EDT

Hurricane response crews from the U.S. Geological Survey are installing more than 120 storm-tide sensors at key locations along the Gulf Coast from the Florida Panhandle to Louisiana in advance of the arrival of Hurricane Isaac.

The storm-tide sensors, frequently called storm-surge sensors, will be secured to piers and poles in areas where the hurricane is expected to make landfall. The instruments being installed will record the precise time the storm-tide arrived, how ocean and inland water levels changed during the storm, the depth of the storm-tide throughout the event, and how long it took for the water to recede.

"While every hurricane brings the possibility for devastation, it also brings a learning opportunity by capturing valuable scientific data that improves our understanding of the pattern and timing of storm-driven coastal inundation," said USGS Director Marcia McNutt. "This vital information will help reduce loss of life and property now and in future events."

Storm-tides are increases in ocean water levels generated at sea by extreme storms and can have devastating coastal impacts. In locations where tidal forecasts are known, the sensors being installed can also help determine storm surge. For differences between storm-surge and tidal-surge, visit the National Hurricane Center's website.

This information will be used to assess storm damage, discern between wind and flood damage, and improve computer models used to forecast future coastal inundation.

In addition, rapid deployment gauges will be installed along critical roadways to provide real-time information to forecast floods and coordinate flood-response activities in the affected areas. The sensors augment a network of existing U.S. Geological Survey gauging stations already in place before the storm arrives.

Of the sensors deployed, 12 of those have real-time capability that will allow viewing of the storm-tide as Hurricane Isaac approaches and makes landfall. The real-time gauges have water level, precipitation and wind sensors that will transmit all data hourly. All gauge data can be found at the USGS Storm-Tide Mapper.

Providing information to support future forecasts could ultimately save lives during future storms. These sensors were deployed for the first time during Hurricane Rita in 2005. Before then, scientists had limited data available to study the effects of storm surge.

"Forecasters at the National Weather Service rely on USGS real-time and long-term data for input into its predictive models that are used to improve storm surge models and prepare storm-tide warnings," said Brian McCallum, assistant director of the USGS Georgia Water Science Center. "Floodplain managers, federal, state and local emergency preparedness officials, emergency responders, scientists and researchers all benefit from the storm-tide and associated flood data. It’s useful for flood damage prevention and public safety."

The USGS studies the impacts of hurricanes and tropical storms to better understand potential impacts on coastal areas. Information provided through the sensor networks provides critical data for more accurate modeling and prediction capabilities and allows for improved structure designs and response for public safety.

The USGS also continuously monitors water levels and flows at thousands of the nation's streams on a real-time basis. The public can access this information for their area at the USGS Current Streamflow Conditions web page. Also, USGS WaterAlert allows users to receive a text or email from the USGS when waters are rising in rivers and streams near them.

For the latest forecasts on the storm, listen to NOAA radio. For information on preparing for the storm, visit Ready.gov or Listo.gov

Isaac Expected to Change Sandy Coasts from Louisiana to Florida

OC_Web@usgs.gov (Office of Communications and Publishing) — Tue, 28 Aug 2012 16:58:32 EDT

Sandy beaches and barrier islands along the northern Gulf of Mexico are highly vulnerable to beach and dune erosion as Hurricane Isaac makes landfall this week, according to a new U.S. Geological Survey assessment. The projections also show which coastal areas may see storm-surge topping sand dunes and beaches.

Probabilities for coastal change have been calculated for parts of the Louisiana, Mississippi, and Alabama coastlines and for the Florida Panhandle.

On Saturday, the USGS released an assessment of expected coastal change in Florida, but the change in the storm’s path has reduced the concern for erosion of west central Florida beaches, shifting focus primarily to sandy beaches and barrier islands from Florida’s Panhandle to Louisiana.

Beaches and dunes can serve as a first line of defense for residents on coasts exposed to these types of storms. During tropical storms and hurricanes, elevated water levels and waves can lead to dramatic coastal change. According to the latest USGS research, during even the weakest hurricanes, wave height and storm surge combine to increase water levels along the Gulf Coast shoreline by 14 and a half feet higher than their normal levels.

"We can now combine more accurate coastal data with powerful new scientific models to provide the very best predictions of hurricane surge, waves, and erosion," said USGS Director Marcia McNutt. "USGS scientists used the latest NOAA forecasts to ensure that the people of the Gulf Coast are not surprised by the impacts of Isaac."

Using a USGS-developed model, scientists incorporated measurements of beach elevation and wave and surge forecasts from the National Oceanic and Atmospheric Administration to determine the probabilities of collision, overwash and inundation during the coming storm.

Collision is when waves attack the base of dunes and cause dune-front erosion. Overwash occurs when waves and storm surge overtop dunes and transport sand landward. Inundation, the most extreme of the three, occurs when increased water levels completely submerge beaches and dunes.

"Earlier this year, USGS released a report detailing hurricane induced erosion hazards for category 1-5 storms. The predictions released this week are based on the same methods, but tailored to waves and storm surge specific to Hurricane Isaac," said Hilary Stockdon, USGS research oceanographer. "As the storm moves across the Gulf, we use real-time storm and wave forecasts from NOAA to determine where beach erosion and inundation are most likely to occur."

These predictions, available on the USGS Hurricanes and Extreme Storms website, show the probable impacts of Isaac at each location along the coast. This assessment may be updated if there are significant changes in the storm’s projected track or strength. Based on the current assessment, the percentages of each type of coastal change were estimated for each of the following states:

Louisiana

Beach and dune erosion is very likely for 66 percent of Louisiana's sandy beaches
29 percent of the sandy beaches in this area are very likely to experience overwash.
18 percent of the Louisiana's barrier islands are expected to be inundated; however, the majority of this inundation will occur only on Louisiana's Chandeleur Islands.
100 percent of the Chandeleur Islands are very likely to experience overwash and 83 percent of these islands are very likely to be inundated. This beach system was devastated during Hurricane Katrina, making it more vulnerable to-low intensity storms.

Mississippi

Beach and dune erosion is very likely for 89 percent of Mississippi's sandy beaches and barrier islands.
20 percent of the sandy beaches are very likely to experience overwash.
Inundation of the beach system is not expected.

Alabama

Beach and dune erosion is very likely for 52 percent of Alabama's sandy beaches and barrier islands.
11 percent of the sandy beaches are very likely to experience overwash.
3 percent of the sandy beaches are very likely to be inundated

Florida Panhandle

Beach and dune erosion is very likely for 32 percent of the Panhandle's sandy beaches
2 percent of the sandy beaches are very likely to experience overwash.
Inundation of the beach system is not expected.

After the worst of the storm passes, USGS may send teams to the field to measure the impact of Hurricane Isaac on the coastline.

Aerial photography and elevation surveys of post-storm beach conditions are used to document the impacts of hurricane waves and currents on the beach. Information obtained from the surveys allows scientists to discern the degree of changes to beaches and coastal environments and determine how much the land has eroded and where new inlets have cut through. The newly acquired data will also be used to make more accurate predictive models of future coastal impacts from severe storms and identify areas vulnerable to extreme coastal change.

The areal photos can visually demonstrate the severe impacts of hurricane surge on beaches. This photo shows the effects that hurricane waves and surge have had on Dauphin Island, Alabama from 2004 -2008.

In May, the USGS released a report assessing probability of coastal change for the Gulf Coast when facing hurricanes of different strengths. The report included an interactive map that allows users to focus on different parts of the Gulf Coast shoreline to view how the probability of erosion, caused by waves and storm surge, will vary depending on hurricane intensity.

For the latest forecasts on the storm, listen to NOAA radio. For information on preparing for the storm, visit Ready.gov or Listo.gov

New Maps for CA, LA and MS Rolling Out

OC_Web@usgs.gov (Office of Communications and Publishing) — Tue, 5 Jun 2012 7:44:13 EDT

California, Louisiana and Mississippi join the more than 40 states covered by the US Topo

In response to the need for up to date map coverage of the United States, the U.S. Geological Survey (USGS) has developed a national map series named the US Topo.With approximately 48,000 new digital maps currently available for free download, more than 4,300 revised quadrangles representing the states of California, Louisiana and Mississippi have been added to the ever-growing collection.

"Anyone who has ever been misrouted on account of outdated software in a GPS navigator can appreciate that maps are constantly in need of updating because both the human and the physical environment are ever changing," said USGS Director Marcia McNutt. "Our new US Topo map series allows users to get the latest data, select just the information of interest for download, and did I emphasize FREE?!"

New feature additions and improvements on the updated US Topo include:

Contours
Rivers, lakes steams and other hydrography
Woodland tint derived from the National Land Cover Dataset
Fire Stations
Hospitals
State and County boundaries
Forest service boundaries
Commercial roads in lieu of Census roads
Forest Service roads and road numbers

US Topos are derived from key layers of geographic data found in The National Map which delivers visible content such as high resolution aerial photography, which is not available on older paper-based topographic maps. The US Topo also provides modern technical advantages over the original lithographic map as it supports wider and faster public distribution and enables on-screen geographic analysis for users.

Future enhancements to the US Topo are scheduled to include additional functional capabilities and content, such as a shaded relief layer, Public Land Survey System (PLSS) data, updated structures, enhanced transportation, additional federal boundaries, and Forest Service trails. The USGS expects to produce more than 18,500 revised quadrangles annually, which means each US Topo map is updated every three years in a cyclic fashion.

The new digital electronic topographic maps of California, Louisiana and Mississippi – along with 37 other completed states - are now available for free download from the USGS Store. The quadrangles are delivered in GeoPDF format and may be viewed using Adobe Reader software, also available as a no cost download.

Gulf Coast Vulnerable to Extreme Erosion in Category 1 Hurricanes: New Model to Help Community Planners, Emergency Managers

OC_Web@usgs.gov (Office of Communications and Publishing) — Wed, 30 May 2012 8:30:00 EDT

Seventy percent of the Gulf of Mexico shoreline is vulnerable to extreme erosion during even the weakest hurricanes, according to a new report by the U.S. Geological Survey released just prior to the start of the 2012 hurricane season.

USGS scientists used state-of-the-art modeling to determine the probabilities of erosion, overwash and inundation during direct hurricane landfall for sandy beaches along the entire U.S. Gulf Coast shoreline.

The research is expected to help emergency managers at local, state and federal levels as they prepare for hurricane events in this and future seasons. Planners will be able to determine how different categories of hurricanes would impact their beaches and surrounding communities, helping them better protect lives and property. The report also includes an interactive map that allows users to focus on different parts of the Gulf Coast shoreline to view how the probability of erosion, caused by waves and storm surge, will vary depending on hurricane intensity.

"The Gulf Coast's beaches provide abundant recreational opportunities, contribute substantially to the local economy, and demand the highest real estate values," said USGS Director Marcia McNutt. "This important research raises awareness on the specific nature of the vulnerability of these beautiful beaches to impacts from even Cat-1 hurricanes so that property damage can be minimized through proper planning."

In a storm, high waves and storm surge can act together to erode beaches and inundate low-lying lands; during hurricane landfall, these changes can sometimes be catastrophic.

"Beaches along the Gulf of Mexico are extremely vulnerable to erosion during hurricanes, in part, because of low elevations along the coast," said Hilary Stockdon, a USGS research oceanographer and lead author of the study. "For example, the average elevation of sand dunes on the west coast of Florida is eight feet. On Florida’s Atlantic coast, the average is 15 feet."

During the landfall of a category-1 storm, where winds are between 75 and 94 miles per hour, overwash is very likely for 70 percent of Gulf Coast beaches. Overwash occurs when waves and storm surge overtop dunes and transport sand landward. Overwash is likely at these locations because of increased water levels at the shoreline. During category-1 hurricane events on the Gulf Coast, wave height and storm surge combine to increase water levels at the shoreline by 14 and a half feet higher than their normal levels.

"People continue to build communities in coastal areas that shift and move with each passing storm," said Stockdon. "This model helps us predict the potential impact of future storms and allows us to identify where the most vulnerable areas are located along the coast."

Additional findings from the report show that during a category-1 storm landfall, 27 percent of sandy beaches along the U.S. Gulf of Mexico are projected to be inundated, which occurs when increased water levels completely submerge beaches and dunes. If category-5 storms occur, where winds are 157 miles per hour or higher, 89 percent of these beaches are likely to be inundated during a direct landfall.

USGS scientists used methodology developed from a decade of USGS research on storm-driven coastal change hazards as the basis for these calculations. Observational data were combined with sophisticated hydrodynamic modeling to predict the coastal changes provided in the report. As new data and storm predictions become available, the report's analysis will be updated to describe how coastal vulnerability may change in the future.

Key findings and the full report are available online.

A similar report detailing erosion hazards along the east coast is planned later this year. This report will provide an assessment of vulnerability for east coast barrier island communities.

A Big Day for Science: Citizens Have Contributed One Million Observations to Top Nature Database

OC_Web@usgs.gov (Office of Communications and Publishing) — Thu, 3 May 2012 9:00:00 EDT

RESTON, Va. — Thanks to citizen-scientists around the country, the USA National Phenology Network hit a major milestone this week by reaching its one millionth nature observation.

The millionth observation was done by Lucille Tower, a citizen-scientist in Portland, Ore., who entered a record about seeing maple vines flowering. Her data, like all of the entries, came in through USA-NPN’s online observation program, Nature's Notebook, which engages more than 4,000 volunteers across the country to observe and record phenology – the timing of the recurring life events of plants and animals such as when cherry trees or lilacs blossom, when robins build their nests, when salmon swim upstream to spawn or when leaves turn colors in the fall.

Each record not only represents a single data point — the status of a specific life stage of an individual plant or animal on one day – but also benefits both science and society by helping researchers understand how plants and animals are responding to climate change and, in turn, how those responses are affecting people and ecological systems.

"My dream is that through the wonders of modern technology and the National Phenology Network we could turn the more than six billion people on the planet into components of our scientific observing system," said USGS Director Marcia McNutt. "We could make giant leaps in science education, improve the spatial and temporal coverage of the planet, lower the cost of scientific data collection, and all while making ordinary citizens feel a part of the scientific process."

Jake Weltzin, a U.S. Geological Survey scientist and the executive director of USA-NPN, concurs. "Hitting the one millionth observation is exciting because researchers and decision-makers need more information to understand and respond to our rapidly changing planet. More information means better-informed decisions that ensure the continued vitality of our natural areas that we all depend on and enjoy."

For example, said Weltzin, the data in Nature's Notebook are already being used to benefit society, including the development of more accurate indicators of spring, forecasting the onset of allergy seasons or the chances of western wildfires, managing wildlife and invasive plants, and setting goals for habitat restoration. Ultimately, such information can be used for better managing water resources, wildlife and ecosystem management, and even help farmers and ranchers across the nation.

Changes in phenology are among the most sensitive biological indicators of global change. Across the world, many springtime events are occurring earlier — and fall events happening later — than in the past. These changes are happening quickly for some species and more slowly, or not at all, for others, altering relationships and processes that have been dynamically stable for thousands of years. Some wildlife —like caribou and butterflies — are becoming mismatched from their plant food resources, which are responding differently. Migrations for some birds are changing too, as they can now overwinter instead of moving south for the winter, or as they fly north more quickly to keep pace with an advancing front of spring flowering.

Because of this, said Weltzin, scientists need more and better information about the pace and pattern of nature — locally to nationally — to answer important scientific and societal questions, and to build the tools and models needed to help people understand and adapt to the changes.

"So much of our improved understanding about global environmental changes is driven by varied and valuable sources of information that include networks of citizen-scientists," said John Wingfield, National Science Foundation’s assistant director for biological sciences. "The public at large has played an important role collecting observations and data for a hundred years and more. Knowledge and data gained from their work will continue to have a lasting effect on how we understand regularly recurring biological phenomena for hundreds of plant and animal species and contribute to the policy arena."

Gwen Lundburg in Seattle is one citizen-scientist who has contributed hundreds of entries into Nature’s Notebook. "Just noticing small changes like tiny purple lilac buds suddenly turning green has taught me to look more closely at my plants," Lundburg said. "I see things in my garden I never saw before."

With the help of citizen-scientist volunteers, working in concert with professionals, the USA-NPN, which was established in 2007, collects, stores and freely shares phenological data on more than 800 species of plants and animals. The Nature’s Notebook observing program has been in operation since 2009. The coordinating office of the organization is located at 1955 E. 6^th St., Tucson, Ariz., 85721. For more information, visit the USA National Phenology Network, or contact Jake Weltzin at 520-626-3821 or jweltzin@usgs.gov.

Rise in Asian Tiger Shrimp Sightings Prompts Scientific Look at Invasion Concerns

OC_Web@usgs.gov (Office of Communications and Publishing) — Thu, 26 Apr 2012 11:00:00 EDT

Additional Contact: Keeley Belva, NOAA 301-713-3066 Keeley.Belva@noaa.gov

Content updated - 4/26/2012 6:48 pm

GAINESVILLE, Fla. – The recent rise in sightings of non-native Asian tiger shrimp off the U.S. Atlantic and Gulf of Mexico coasts has government scientists working to determine the cause of the increase and the possible consequences for native fish and seafood in those waters.

Researchers from the U.S. Geological Survey and National Oceanic and Atmospheric Administration are working with state agencies from North Carolina to Texas to look into how this transplanted species from Indo-Pacific, Asian and Australian waters reached U.S. waters, and what the increase in sightings means for native species.

"We can confirm there was nearly a tenfold jump in reports of Asian tiger shrimp in 2011," explained Pam Fuller, the USGS biologist who runs the agency's Nonindigenous Aquatic Species database. "And they are probably even more prevalent than reports suggest, because the more fisherman and other locals become accustomed to seeing them, the less likely they are to report them."

NOAA scientists are launching a research effort to understand more about the biology of these shrimp and how they may affect the ecology of native fisheries and coastal ecosystems. As with all non-native species, there are concerns over the potential for novel avenues of disease transmission and competition with native shrimp stocks, especially given the high growth rates and spawning rates compared with other species.

"The Asian tiger shrimp represents yet another potential marine invader capable of altering fragile marine ecosystems," said NOAA marine ecologist James Morris. "Our efforts will include assessments of the biology and ecology of this non-native species and attempts to predict impacts to economically and ecologically important species of the Atlantic and Gulf of Mexico."

The cause of the rapid increase in sightings remains uncertain, Fuller added. The non-native shrimp species may have escaped from aquaculture facilities, although there are no longer any known Asian tiger shrimp farms presently in operation in the United States. It may have been transported in ballast water from ships or possibly arrived on ocean currents from wild populations in the Caribbean or other locations.

Fuller's team at USGS has been tracking reports of Asian tiger shrimp since they first came to the attention of marine scientists and resource managers in 1988, when nearly 300 of them were collected off the coasts of South Carolina, Georgia and Florida within three months. Scientists tracked the cause back to an isolated incident that accidentally caused an estimated 2,000 animals to be released from an aquaculture facility operating at that time in South Carolina.

It was not until 18 years later that reports of the non-native shrimp resurfaced. In 2006, a commercial shrimp fisherman caught a single adult male in Mississippi Sound near Dauphin Island, Ala. Within months, additional specimens were noted in North Carolina’s Pamlico Sound, Louisiana’s Vermilion Bay and other parts of Florida and the Carolinas. The species was later reported off the coasts of Georgia, Mississippi and Texas in 2008, 2009 and 2011, respectively.

Scientists have not yet officially deemed the Asian tiger shrimp "established" in U.S. waters, and no one is certain what triggered the recent round of sightings. With so many alternative theories about where these shrimp are coming from and only a handful of juveniles reported, it is hard for scientists to conclude whether they are breeding or simply being carried in by currents.

To look for answers, USGS and NOAA scientists are examining shrimp collected from the Gulf and Atlantic coasts to look for subtle differences in their DNA, information that could offer valuable clues to their origins. This is the first look at the genetics of wild caught Asian tiger shrimp populations found in this part of the U.S., and may shed light on whether there are multiple sources.

"We're going to start by searching for subtle differences in the DNA of Asian tiger shrimp found here – outside their native range –to see if we can learn more about how they got here," said USGS geneticist Margaret Hunter, "If we find differences, the next step will be to fine-tune the analysis to determine whether they are breeding here, have multiple populations, or are carried in from outside areas."

Anyone who sees one or more shrimp suspected to be an Asian tiger shrimp is asked to note the location and report the sighting to the USGS NAS database. If possible, freeze a specimen to help confirm the identity and contribute to a tissue repository maintained by NOAA.

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Satellite Tracking Reveals Sea Turtle Feeding Hotspots

OC_Web@usgs.gov (Office of Communications and Publishing) — Wed, 1 Feb 2012 15:00:00 EDT

Study Offers Clues to Loggerheads' Elusive Habits at Sea

GAINESVILLE, Fla. – Satellite tracking of threatened loggerhead sea turtles has revealed two previously unknown feeding ‘hotspots’ in the Gulf of Mexico that are providing important habitat for at least three separate populations of the turtles, according to a study published recently in the journal Biological Conservation.

The two sites, located in the open waters off the coast of Southwest Florida and the northern tip of the Yucatan Peninsula, were found by a team of scientists when they compiled and analyzed loggerhead tracking data.

The researchers' goal was to synthesize tracking data from three genetically distinct loggerhead populations to learn more about how they use the Gulf of Mexico. By identifying the specific location of regularly used habitat, the results provide invaluable information for marine planning and management for this species, whose populations in the Gulf of Mexico are well below historic levels and in recent years have continued to decline drastically in some areas.

The maritime feeding grounds also hold the first clues about how loggerhead sea turtles spend time at sea – which is, in essence, most of their lives.

"Up until now, management actions that affect loggerheads have often focused on their limited time at nesting beaches, or on fisheries regulations," said Kristen Hart, Ph.D., the U.S. Geological Survey research ecologist who led the synthesis. "Our findings open up important new options for marine habitat conservation, and provide valuable geographic data that can be used to strategically locate marine reserves based on the best available science, as called for in the new National Ocean Policy."

"The use of satellite tags for tracking marine animals has opened our eyes to the secret lives of some of nature's most elusive creatures," said USGS director Marcia McNutt, "At first a scientific tool to understand the life cycle of animals, such as white sharks and leatherback turtles, who rarely come into contact with humans, these tags may now be the main hope for understanding what we can do, or what we should stop doing, in order to bring them back from the road to extinction."

Researchers intercepted female loggerheads after their nesting forays to beaches and outfitted them with satellite tags at study sites in the Florida Panhandle, Casey Key in southwest Florida, and Dry Tortugas National Park. They then tracked the females’ migrations and used a new method to determine precisely when they had arrived at "hotspot" foraging areas, in two geographically different locations.

Seven female turtles migrated to foraging sites off Southwest Florida, while the other three took up residence at foraging sites at the Yucatan site. Once the researchers applied the new method for synthesizing their satellite-tracking data, it became clear that these loggerhead turtles from all three populations consistently converged around two common sites. This confirmed a hunch that the researchers had developed after years of tracking turtles.

At both of the feeding hotspots, turtles selected individual sites where they foraged in shallow or nearshore waters less than fifty meters deep. Turtles appeared to prefer their own distinct territories, where they tended to remain resident. This suggests that it may be possible to accurately predict where sea turtles will feed, information that will prove vital for managers looking to focus conservation efforts on prime foraging habitat.

Researchers don't yet know what attracts loggerheads from around the Gulf to these specific feeding areas, although generally, loggerheads forage on the bottom of the sea floor for crustaceans such as crabs, lobsters, clams or conchs.

"The logical next step is to investigate what makes these particular sites 'prime' foraging grounds by mapping and sampling the habitat types found on the sea floor," explained Hart. "It would also be useful to tag loggerheads at these foraging sites to confirm how long they reside in these areas, or alternatively to see where they go next."

Groundwater Storage Losses Substantial Across Eight State Aquifer System

OC_Web@usgs.gov (Office of Communications and Publishing) — Thu, 1 Dec 2011 13:10:46 EDT

More than 280 million acre-feet of groundwater has been withdrawn from the Mississippi embayment aquifer system between 1870-2007, according to a new water modeling tool developed by the U.S. Geological Survey.

This cumulative withdrawal, which is the equivalent of five feet of water over 78,000 square miles, contributes to one of the largest losses of groundwater storage anywhere in the United States.

The new USGS modeling tool was designed to help resource managers find a balance between water supply and demand for future economic and environmental uses. The three-dimensional model provides a holistic picture of how water flows below ground and how it relates to surface-water. The Mississippi embayment aquifer system encompasses approximately 78,000 square miles in Alabama, Arkansas, Illinois, Kentucky, Louisiana, Mississippi, Missouri and Tennessee. A report documenting past and current groundwater conditions, and tools to forecast regional response to human use, climate variability, and land-use changes are all available online.

"Our groundwater aquifers are nature's own natural method for storing water safely long term where it is less vulnerable to loss through evaporation and surface contamination," explained USGS director Marcia McNutt. "We should be as concerned about loss of groundwater as we are about dropping levels in reservoirs behind dams, because in the depths of the worst drought, when the rivers run dry, it is only the groundwater that will sustain us."

"This model can assist water resource managers faced with increasing management challenges and constraints," said USGS hydrologist, Brian Clark. "This model could be used to evaluate regional issues, such as streamflow declines from groundwater pumping or conservation scenarios to lessen water level declines."

The Mississippi embayment aquifer system includes one of the nation’s most productive agricultural regions, with an annual value of $3 billion per year. Two of the region’s most important aquifers lie beneath the Mississippi embayment. The pumping from the Mississippi River Valley alluvial aquifer accounts for more than 12 percent of all groundwater pumped in the United States.

"This model will help officials find ways to better manage the area's present and future groundwater resources," said USGS Arkansas Water Science Center Director, Dave Freiwald. "This is the most recent large-scale, comprehensive assessment of groundwater resources in the area."

This report is a product of a four-year study being funded by the USGS Groundwater Resources Program. Information derived from this and future studies of more than 30 regional aquifers will provide a collective assessment of America's groundwater availability.

To develop the model, scientists examined more than 2,600 geophysical logs, some dating back to the early 1960’s. Researchers examined groundwater and surface-water data from the early 1900’s to 2007, groundwater withdrawal information, and thousands of miles of surface-water bodies to illustrate how the water system works and how supplies have changed.

A comprehensive report detailing the research, “Groundwater Availability of the Mississippi Embayment,” and a factsheet, “A New Tool to Assess Groundwater Resources in the Mississippi Embayment,” are available online.

Map showing the Mississippi embayment aquifer system area. (Larger image)

Landsat 5 Satellite Sees Mississippi River Floodwaters Lingering

OC_Web@usgs.gov (Office of Communications and Publishing) — Thu, 16 Jun 2011 12:20:00 EDT

IMAGE FEATURE

In this Landsat 5 satellite image captured June 11, flooding is still evident both east and west of the Mississippi River near Vicksburg, Mississippi. Standing water is most apparent, however, in the floodplain between the Yazoo and Mississippi Rivers north and northwest of Vicksburg.

According to the National Weather Service, the Mississippi River reached a historic crest (57.10 feet) at Vicksburg on May 19, 2011.

By early June, flooding had receded considerably around Vicksburg, but water remained high. On June 14, the Mississippi River measured 44.88 feet at Vicksburg. At that point, the river was in minor flood stage and its level was forecast to continue falling through June 19.

The Landsat series of satellites is used by emergency managers to acquire a range of imagery, from floods to fires. Landsat has recently provided both images of the flooding of the Mississippi River and the fires raging in Arizona.

Landsat is a joint effort of both USGS and NASA. USGS conducts Landsat operations and NASA develops and launches new satellites that meet USGS requirements. In addition to imagery of natural hazard events, Landsat provides valuable data for land use research and advances the Department of the Interior’s important role in land remote sensing under the President’s National Space Policy. Landsat images are unique in that they provide complete global coverage, they are available for free, and they span nearly 40 years of continuous earth observation. No other satellite imagery has that combination of attributes.