USGS Newsroom

Deficit in Nation's Aquifers Accelerating

OC_Web@usgs.gov (Office of Communications and Publishing) — Mon, 20 May 2013 8:00:00 EDT

A new U.S. Geological Survey study documents that the Nation's aquifers are being drawn down at an accelerating rate.

Groundwater Depletion in the United States (1900-2008) comprehensively evaluates long-term cumulative depletion volumes in 40 separate aquifers (distinct underground water storage areas) in the United States, bringing together reliable information from previous references and from new analyses.

"Groundwater is one of the Nation's most important natural resources. It provides drinking water in both rural and urban communities. It supports irrigation and industry, sustains the flow of streams and rivers, and maintains ecosystems," said Suzette Kimball, acting USGS Director. "Because groundwater systems typically respond slowly to human actions, a long-term perspective is vital to manage this valuable resource in sustainable ways."

To outline the scale of groundwater depletion across the country, here are two startling facts drawn from the study's wealth of statistics. First, from 1900 to 2008, the Nation's aquifers, the natural stocks of water found under the land, decreased (were depleted) by more than twice the volume of water found in Lake Erie. Second, groundwater depletion in the U.S. in the years 2000-2008 can explain more than 2 percent of the observed global sea-level rise during that period.

Since 1950, the use of groundwater resources for agricultural, industrial, and municipal purposes has greatly expanded in the United States. When groundwater is withdrawn from subsurface storage faster than it is recharged by precipitation or other water sources, the result is groundwater depletion. The depletion of groundwater has many negative consequences, including land subsidence, reduced well yields, and diminished spring and stream flows.

While the rate of groundwater depletion across the country has increased markedly since about 1950, the maximum rates have occurred during the most recent period of the study (2000–2008), when the depletion rate averaged almost 25 cubic kilometers per year. For comparison, 9.2 cubic kilometers per year is the historical average calculated over the 1900–2008 timespan of the study.

One of the best known and most investigated aquifers in the U.S. is the High Plains (or Ogallala) aquifer. It underlies more than 170,000 square miles of the Nation's midsection and represents the principal source of water for irrigation and drinking in this major agricultural area. Substantial pumping of the High Plains aquifer for irrigation since the 1940s has resulted in large water-table declines that exceed 160 feet in places.

The study shows that, since 2000, depletion of the High Plains aquifer appears to be continuing at a high rate. The depletion during the last 8 years of record (2001–2008, inclusive) is about 32 percent of the cumulative depletion in this aquifer during the entire 20th century. The annual rate of depletion during this recent period averaged about 10.2 cubic kilometers, roughly 2 percent of the volume of water in Lake Erie.

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National Assessment Shows Geographic Distributions and Trends of Pesticide Use, 1992-2009

OC_Web@usgs.gov (Office of Communications and Publishing) — Thu, 16 May 2013 11:35:02 EDT

For the first time, national maps and trend graphs show the distribution of the agricultural use of 459 pesticides for each year during 1992-2009 for the entire conterminous U.S. The maps and supporting national database of county-level use estimates for each pesticide were developed by the U.S. Geological Survey (USGS) for use in national and regional water-quality assessments.

The national use analysis is based on methods developed by USGS to estimate annual county-level pesticide use for agricultural crops grown throughout the conterminous United States. Pesticide-use data compiled from proprietary surveys of farm operations were used in conjunction with annual harvested-crop acreage reported by the U.S. Department of Agriculture (USDA) to calculate use rates for each crop and year. For California, use estimates were obtained directly from annual California Department of Pesticide Regulation Pesticide Use Reports.

"These nationally complete and consistent, county-level use estimates are vital for USGS water-quality models that estimate pesticide concentrations in streams and rivers. In addition, long-term annual data is essential for interpreting water-quality trends," said Wes Stone, an author of the reports.

The new pesticide-use estimates were tested and found to be consistent with national use estimates by the U.S. Environmental Protection Agency and with comparable statewide estimates for selected years and crops by the USDA. The USDA data on pesticide use, which are based on systematic regional surveys for selected years and crops, enabled vital quality assurance of the new estimates.

Gail Thelin, senior author of the report on estimation methods, noted, "When evaluated statistically, USGS estimates agree with estimates from other sources for comparable years, pesticides, and states. That consistency supports the reliability of the comprehensive and long-term assessment of use patterns and trends that is now available through this study."

Complete results of the USGS analysis of pesticide use are provided in three products:

Documentation of Methods: "Estimation of annual agricultural pesticide use for counties of the conterminous United States, 1992–2009": U.S. Geological Survey Scientific Investigations Report 2013-5009

National County-Level Data for 459 Pesticides: "Estimated annual agricultural pesticide use for counties of the conterminous United States, 1992–2009": U.S. Geological Survey Data Series 752

National Maps and Trend Graphs

Spring 2012 Earliest on Record

OC_Web@usgs.gov (Office of Communications and Publishing) — Wed, 15 May 2013 13:25:26 EDT

March 2012 set records for warm temperatures that promoted early leafing and flowering across large areas of the United States. A team of scientists at the USA National Phenology Network, which is sponsored by the U.S. Geological Survey, have published a study which shows that 2012 was the earliest spring over the 48 U.S. states since 1900 when systematic weather data began to be available for the entire area.

Phenology is the study of recurring plant and animal life cycle stages, especially their timing and relationships with weather and climate. Assessing the severity and impacts of such extreme climatic events, either in the past or as they happen, requires consistent indicators of variability and change that can be mapped both nationally and historically.

The USA National Phenology Network provides a suite of "spring indices" based on the accumulated warmth needed to end dormancy and initiate growth in many native and cultivated plants. These complex, evidence-based algorithms can be calculated for any weather station that records daily maximum and minimum temperatures. Spring indices are independently validated using historical observations of leafing and flowering in lilac and honeysuckle nationwide.

The historical trend of spring indices suggests that the 2012 growing season advanced as much as 20-30 days in the East and Midwest from the 1900-2012 long-term mean.

"The results of this study clearly demonstrate the great importance of long-term monitoring of natural processes. A long record allows us to identify patterns of change that we might otherwise miss," said Suzette Kimball, acting USGS Director.

Today the response of vegetation to temperature and precipitation can be readily observed across wide areas by Earth-observing satellites at intervals of only a few days. USGS scientist Julio Betancourt, a co-author of the study, noted, "Indicators such as spring indices and satellite-based evaluations of vegetation growth will become essential tools for assessing climate variability and change and their impacts."

Satellite data show that the cumulative effects of the unusually early 2012 spring were most pronounced across the Corn Belt, the western Great Lakes region, and the northeastern U.S.

The beneficial effects of spring's quick start in 2012 were subsequently offset by a late spring frost and summer drought. In fact, the unusually early spring combined with late frosts in April to produce a so-called "false spring" that damaged fruit trees across the Upper Midwest and Great Lakes regions.

The study appears in EOS, Transactions of the American Geophysical Union.

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Three Iowa Streamgages Shutting Down on Friday

OC_Web@usgs.gov (Office of Communications and Publishing) — Wed, 15 May 2013 13:21:27 EDT

Three U.S. Geological Survey streamgages in Iowa, which measure streamflow and water level, will be shut down on Friday, May 17, due to the federal budget sequestration.

The affected Iowa streamgages will be discontinued beginning this Friday because of a five-percent sequestration-related budget cut to the USGS National Streamflow Information Program (NSIP). Of the 35 NSIP-funded streamgages in Iowa, 22 of which are fully funded by NSIP, the USGS Iowa Water Science Center selected the following three for shutdown:

West Fork Cedar River at Finchford, Iowa (66 years of record)
Des Moines River at Humboldt, Iowa (47 years of record)
East Fork 102 River at Bedford, Iowa (29 years of record)

"It was difficult to make a selection that minimized all concerns, but these three Iowa streamgages will be shut down because they have comparatively short records, limited impacts on partner organizations, and their discontinuation is least likely to affect public safety," said USGS hydrologist Jon Nania.

According to the National Weather Service (NWS), local communities may receive less accurate river flood forecasts and less advanced notice of flooding due to the shutdown of these streamgages. Communities that may be impacted include Waterloo, Cedar Falls, Fort Dodge, Finchford, and Bedford, Iowa, and Maryville, Mo.

"Streamgages like these help communities understand how and when to prepare for floods," said Jeff Zogg, a NWS Senior Hydrologist in Des Moines. "In some past floods, the peak streamflows measured by these gages have contributed several feet to the downstream crests."

Streamgages collect critical streamflow and water availability data that are used by organizations nationwide to predict and address drought and flood conditions. The USGS and over 850 federal, state, and local agencies cooperatively fund the USGS streamgaging network, which consists of over 8,000 streamgages.

The USGS will discontinue operation of no more than 200 streamgages nationwide due to budget cuts as a result of sequestration. Additional streamgages may be affected if partners reduce their funding to support USGS streamgages. The USGS is working to identify which streamgages will be impacted and will post this information online as it becomes available.

More information about streamgaging in Iowa is available on the USGS Iowa Water Science Center website.

More information about NWS flood forecasts and warnings is available on the NWS Des Moines website, and on Facebook and Twitter @NWSDesMoines.

Warmer Springs Causing Loss of Snow Cover throughout the Rocky Mountains

OC_Web@usgs.gov (Office of Communications and Publishing) — Mon, 13 May 2013 14:00:00 EDT

BOZEMAN, Mont. – Warmer spring temperatures since 1980 are causing an estimated 20 percent loss of snow cover across the Rocky Mountains of western North America, according to new research from the U.S. Geological Survey.

The new study builds upon a previous USGS snowpack investigation which showed that, until the 1980s, the northern Rocky Mountains experienced large snowpacks when the central and southern Rockies experienced meager ones, and vice versa. Yet, since the 1980s, there have been simultaneous snowpack declines along the entire length of the Rocky Mountains, and unusually severe declines in the north.

The new study has teased apart and quantified the different influences of winter temperature, spring temperature, and precipitation on historic snowpack variations and trends in the region. To distinguish those varying influences, the researchers implemented a regional snow model that uses inputs of monthly temperature and precipitation data from 1895 to 2011.

"Each year we looked at temperature and precipitation variations and the amount of water contained within the snowpack as of April," said USGS scientist Greg Pederson, the lead author of the study. "Snow deficits were consistent throughout the Rockies due to the lack of precipitation during the cool seasons during the 1930s – coinciding with the Dust Bowl era. From 1980 on, warmer spring temperatures melted snowpack throughout the Rockies early, regardless of winter precipitation. The model in turn shows temperature as the major driving factor in snowpack declines over the past thirty years."

Runoff from Rocky Mountain winter snowpack accounts for 60 to 80 percent of the annual water supply for more than 70 million people living in the western U.S., and is influenced by factors such as the snowpack’s water content, known as snow water equivalent, and the timing of snowmelt.

The timing of snowmelt affects not only when water is available for crop irrigation and energy production from hydroelectric dams, but also the risk of regional floods and wildfires. Earlier and faster snowmelt could have repercussions for water supply, risk management, and ecosystem health in western watersheds.

Regional snowpack accumulation is highly sensitive to variations in both temperature and precipitation over time. Patterns and sources of these variations are difficult to discern due to complex mountain topography, the different influence of Pacific Ocean climate, like La Niña and El Niño, on winter precipitation in the northern versus southern and central Rockies, and the brevity and patchiness of detailed snow records.

In the study, the regional snow model used by Pederson and his USGS colleagues Julio Betancourt and Greg McCabe allows estimation of snow water and cover variability at different latitudes and elevations during the last century regardless of the absence of direct and long-term observations everywhere. Recent snowpack variations also were evaluated in the context of snowpack evidence from tree-rings, allowing the scientists to compare recent observations to measurements from the past 800 years.

McCabe, co-author of the study, explains that "recent springtime warming also reduced the extent of snow cover at low to middle elevations where temperature has had the greatest impact."

"Both natural variability in temperature and anthropogenic warming have contributed to the recent snowpack decline, though disentangling their influences exactly remains elusive." Betancourt said,

"Regardless of the ultimate causes, continuation of present snowpack trends in the Rocky Mountains will pose difficult challenges for watershed management and conventional water planning in the American West."

The study, "Regional patterns and proximal causes of the recent snowpack decline in the Rocky Mountains," is available from Geophysical Research Letters, a journal of the American Geophysical Union.

Decades-old Nitrate Found to Affect Stream Water Quality

OC_Web@usgs.gov (Office of Communications and Publishing) — Tue, 7 May 2013 8:31:59 EDT

USGS hydrologic researchers have found that the movement of nitrate through groundwater to streams can take decades to occur. This long lag time means that changes in the use of nitrogen-based fertilizer (the typical source of nitrate) — whether the change is initiation, adjustment, or cessation — may take decades to be fully observed in streams, according to a recent study published in the journal Environmental Science and Technology.

Water quality experts have been noting in recent years that nitrate trends in streams and rivers do not match their expectations based on reduced regional use of nitrogen-based fertilizer. The long travel times of groundwater discharge, like those documented in this study, have previously been suggested as the likely factor responsible for these observations.

"This study provides direct evidence that nitrate can take decades to travel from recharge at the land surface to discharge in streams," said Jerad Bales, acting USGS Associate Director for Water. "This is an important finding because long travel times will delay direct observation of the full effect of nutrient management strategies on stream quality."

Rivers and streams are fed by both groundwater held in underground aquifers and surface water from precipitation runoff. In low streamflow conditions, groundwater sources take a larger role.

In this study, USGS scientists closely examined surface and ground waters at seven study sites from across the nation to determine the portion of stream nitrate derived from groundwater. They found that most of the nitrate observed in streams located in groundwater-dominated watersheds was derived from groundwater sources. To determine the time it takes groundwater to reach a stream in a groundwater-dominated watershed, an age dating tracer study was conducted in the Tomorrow River in central Wisconsin. The findings indicated that decades-old nitrate-laden water was currently discharging to this stream. Consequently, base flow nitrate concentrations in this stream may be sustained for decades to come, regardless of current and future practices.

The slow release of groundwater nitrate to streams may also affect the water quality of large rivers. For example, increases in nitrate concentrations during low and moderate flows in large rivers in the Mississippi River Basin have been observed to be greater than or comparable to increases in nitrate concentrations during high flows. (See USGS website, Nitrate in the Mississippi River and its tributaries, 1980 to 2008.) These findings also suggest that increasing nitrate concentrations in groundwater are having a substantial effect on nitrate concentrations in rivers and nitrate transport to the Gulf of Mexico. Because nitrate moves slowly through groundwater to rivers, the full effect of management strategies designed to reduce nitrate movement to these rivers may not be seen for many years.

Citation

"Vulnerability of Streams to Legacy Nitrate Sources"
Anthony J. Tesoriero, John H. Duff, David A. Saad, Norman E. Spahr, and David M. Wolock
Environmental Science & Technology; April 16, 2013

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USGS Continues to Provide Critical Flood Information

OC_Web@usgs.gov (Office of Communications and Publishing) — Thu, 2 May 2013 16:15:43 EDT

As lingering spring rains soak eastern Iowa, crews from the U.S. Geological Survey continue efforts to make sure the streamgaging network is providing basic scientific information needed by water-resource managers and the community.

"The accurate flow data from the USGS is an essential part of NWS flood forecasts and warnings," said Jeff Zogg, NWS Senior Service Hydrologist. "Even small errors can negatively impact flood forecasts."

The National Weather Service uses USGS streamgaging information for flood forecasting. When flooding is frequent, the NWS stays in constant contact with the USGS. The USGS streamgaging network is the principal source of data used by the NWS to develop flood forecasts because of the stage and discharge information they provide.

The USGS operates 150 gages in Iowa that collect both stage and discharge information.

A reliable flood forecast, and subsequent warnings, requires a current source of stage, discharge, and precipitation data. NWS flood forecasts are based on river models that provide estimates of how a river will respond to rainfall. River stage and discharge data provided by USGS gaging stations are essential components of these river models and flood forecasts.

"The USGS places the utmost importance on the high quality and consistency of its streamgage network," said Kevin Richards, Director of the USGS Iowa Water Science Center. "Streamflow information is used in countless ways by government agencies, private industries, and the general public."

In addition to routine discharge measurements made at USGS streamgages, the USGS made 34 additional flood measurements once the rivers started rising in mid-April. With the forecasts calling for additional rain and snow over the next week, USGS scientists will be making extra measurements and checking equipment to assure the information is available for decision makers.

The real-time streamgaging information is available on the USGS Iowa website. Access current flood and high flow conditions across the country by visiting the USGS WaterWatch website.

Receive instant, customized updates about water conditions in your area via text message or email by signing up for USGS WaterAlert.

Streamgages Measure High Flows in Michigan

OC_Web@usgs.gov (Office of Communications and Publishing) — Tue, 30 Apr 2013 10:40:34 EDT

Reporters: Do you want to accompany a USGS field crew as they measure flooding? Please contact Tom Weaver at 517-887-8923.

U.S. Geological Survey field crews have been measuring increased streamflow on numerous Michigan rivers in response to heavy rainfall in parts of the Lower Peninsula this April. The USGS Grand River at Ionia streamgage in west-central Michigan recorded its highest streamflow of record, which began in 1949. Preliminary analysis indicate that there is only a 1 to 2 percent chance that flows larger than the measured 25,100 cubic feet per second will occur in any given year at the Ionia streamgage.

Further downstream at the Grand River at Grand Rapids streamgage, the fifth largest flow since 1904 was recorded with a 4 to 10 percent chance of being exceeded in any given year. Upstream from Ionia at the Grand River at Lansing streamgage, peak flows had greater than 20 percent chance of being exceeded in any given year. High flows were also measured at USGS streamgages located in the Kalamazoo, Muskegon, Rifle, St. Joseph, and Saginaw River basins.

The likelihood of a peak flow event can be expressed, as above, using the annual exceedance probability, or its reciprocal, the recurrence interval. For example, a peak flow having a 20 percent chance of occurring in any given year, is equivalent to an event, which over an extended period of time, is exceeded on average once in five years (in the past, referred to as a 5-year flood, and calculated by dividing 1 by 0.20). Neither measure of likelihood can be used to predict the interval between flood events.

USGS scientists are collecting critical streamflow data that are vital for protection of life, property and the environment. These data are used by the National Weather Service to develop flood forecasts, the U.S. Army Corps of Engineers to manage flood control, and the various state and local agencies in their flood response activities. More information is available at the USGS Michigan Water Science Center.

There are 212 USGS-operated stations in Michigan that measure water levels, streamflow, rainfall, and selected water-quality parameters. Most of the USGS stations are realtime sites where data are updated every one to two hours.

For more than 125 years, the USGS has monitored flow in selected streams and rivers across the U.S. The information is routinely used for water supply and management, monitoring floods and droughts, bridge and road design, determination of flood risk, and for many recreational activities.

Access current flood and high flow conditions across the country by visiting the USGS WaterWatch. Receive instant, customized updates about water conditions in your area via text message or email by signing up for USGS WaterAlert. For more information about floods, see the USGS fact sheet, "Flood Hazards—A National Threat."

Helping to Preserve Water Resources around Wichita, Kansas with New Groundwater Model

OC_Web@usgs.gov (Office of Communications and Publishing) — Tue, 30 Apr 2013 10:00:00 EDT

A new model to better describe groundwater changes and chloride movement in the Equus Beds aquifer, a primary water-supply source for the Wichita, Kansas area, has been completed by the U.S. Geological Survey, in cooperation with the City of Wichita.

"This model will help us effectively manage and better preserve our valuable water supplies," said Mike Jacobs, City of Wichita Water Resources Engineer. "This valuable tool will assist in accurately tracking our critical resource by being able to measure the water available, account for water that is artificially recharged into the aquifer, and by monitoring the movement of chloride."

The study began in 2009 to determine groundwater flow in the Wichita well field area, and chloride transport from the Arkansas River and Burrton oil field. This model will be used to determine the effects on groundwater from changes in well pumping, rainfall, and streamflow. Results from this study are available online.

The new tool will assist with overall management in the Equus Beds aquifer, and will be used by water management organizations including: the city of Wichita; Equus Beds Groundwater Management District Number 2; Department of Agriculture, Division of Water Resources and other municipalities.

This model can be used to simulate changes in water withdrawals, changes in water levels caused by drought and/or pumping, and natural and artificial recharge to the aquifer. Artificial recharge is the practice of increasing the amount of water that enters a groundwater reservoir by artificial means. This includes adding water to the land surface in recharge ponds and injection of water into the subsurface through wells.

The model will be used to simulate the movement of chloride because if the levels are high (more than 250 mg/L), the water is less usable as a drinking-water source and for crop irrigation. Chloride is present in nearly all natural waters, although concentrations are normally low. Chloride originates from natural deposits of salt and from past oil and gas brine solutions and disposal.

The Wichita well field was developed in the Equus Beds aquifer northwest of Wichita to supply water to the city. In 1940, the city began pumping from 25 wells in the well field. In addition, nearby agricultural pumpage increased greatly in the 1970s and 1980s. Groundwater pumping from the well field caused water levels to decline over a large part of the study area.

The City of Wichita is in the process of commissioning Phase II of the Equus Beds Aquifer Storage and Recovery (ASR) Project. Phase II completes 25% of the ASR project, which includes: storing and later recovering groundwater; forming a hydraulic barrier to the known chloride-brine plume near Burrton, Kan.; and forming a hydraulic barrier to the chlorides entering the aquifer from the Arkansas River.

Rising Seas Could Threaten Many Acadia NP Marshes

OC_Web@usgs.gov (Office of Communications and Publishing) — Mon, 29 Apr 2013 14:06:12 EDT

The report and maps are available online.

AUGUSTA, Maine – More than 800 acres of uplands in and near Acadia National Park will likely be flooded by the ocean if sea level rises 2 feet during this century, leaving 75 percent of the saltwater marshes along this part of central Maine's rugged coast with very little upland area to migrate into, according to a new U.S. Geological Survey study and maps.

If plant material and sediments can accumulate in Maine's salt marshes fast enough to keep pace with sea-level rise, the uplands could provide areas for new salt marsh habitat. But that would require faster accumulation rates than those observed in the last century.

"The precise amount of sea-level rise that we should expect this century is not known," said USGS scientist Martha Nielsen, who led the study. "This report and maps are intended to inform decision makers with science to assist in planning for an uncertain future. By identifying the uplands that could support new salt marshes ahead of time, we hope to aid land management and preservation efforts to sustain marsh ecosystems in the area."

The study, done in cooperation with the National Park Service, identified more than 40 potential barriers that, in addition to rugged topography, would further restrict inland migration of some marshes. The barriers are mostly roads that limit water and sediment movement. This study is intended to help managers proactively plan for mitigation of those barriers.

Salt marshes provide significant ecological value and aesthetic beauty to Maine's coasts. Their ecological functions include nursery and breeding habitat for many fish, shellfish, and wildlife species; storm, flood, and erosion protection; organic-matter production that feeds many commercially and recreationally valuable species; and filtration for sediments and contaminants.

The study area included all coastal areas in Maine from the eastern half of Penobscot Bay to the eastern edge of the Schoodic Peninsula. The 114 saltwater marshes included in the study range in size from larger than half an acre, up to 128 acres.

The analysis was based on high-resolution elevation data collected for coastal New England in 2010 with American Recovery and Reinvestment Act stimulus funding. The data were independently assessed for accuracy, and the maps show the expected inundation around each marsh to a 95 percent confidence interval. The manmade barriers to migration identified in the study are also shown.

USGS Measures Record Flooding in Illinois

OC_Web@usgs.gov (Office of Communications and Publishing) — Tue, 23 Apr 2013 8:37:32 EDT

Reporters: Do you want to accompany a USGS field crew as they measure flooding? Please contact Ayla Ault at 815-756-9207.

U.S. Geological Survey field crews are measuring record flooding on rivers and streams across most of Illinois.

At least ten USGS streamgages in Illinois that have more than 20 years of record, have measured the highest flood levels ever recorded. More record levels are expected as flooding moves downstream. USGS crews are expected to track the movement of the floodwaters down the Illinois River, the Rock Rivers, and major tributaries over the next few days. Many of the Illinois River floodwaters are expected to exceed records and may result in major flooding that overtop levees. There are 53 USGS streamgages currently at or above flood levels as a result of the rains that began on Tuesday, April 16.

USGS scientists are collecting critical streamflow data that are vital for protection of life, property and the environment. These data are used by the National Weather Service to develop flood forecasts, the U.S. Army Corps of Engineers to manage flood control, the Illinois Department of Natural Resources, and local agencies in their flood response activities. More information is available on the USGS Illinois Water Science Center website.

"These measurements are made using state-of-the-art equipment, including hydroacoustic meters, which gives the USGS the ability to make accurate and reliable streamflow measurements under extreme flow conditions," said USGS hydrologist Gary Johnson. "Accurate streamflow measurements are critical for emergency managers to make important decisions on how to protect life and property."

There are about 250 USGS-operated streamgages in Illinois that measure water levels, streamflow, and rainfall. When flooding occurs, USGS crews make numerous discharge measurements to verify the data USGS provides to federal, state, and local agencies, as well as to the public.

Access current flood and high flow conditions across the country by visiting the USGS WaterWatch website. Receive instant, customized updates about water conditions in your area via text message or email by signing up for USGS WaterAlert.

High Arsenic Levels Found in 8 Percent of Groundwater Wells Studied in Pennsylvania

OC_Web@usgs.gov (Office of Communications and Publishing) — Wed, 17 Apr 2013 9:00:00 EDT

The report and maps are posted online.

NEW CUMBERLAND, Pa. – Eight percent of more than 5,000 wells tested across Pennsylvania contain groundwater with levels of arsenic at or above federal standards set for public drinking water, while an additional 12 percent – though not exceeding standards – show elevated levels of arsenic.

These findings, along with maps depicting areas in the state most likely to have elevated levels of arsenic in groundwater, are part of a recently released U.S. Geological Survey study done in cooperation with the Pennsylvania Departments of Health and Environmental Protection.

The results highlight the importance of private well owners testing and potentially treating their water. While public water supplies are treated to ensure that water reaching the tap of households meets federal drinking water standards, private wells are unregulated in Pennsylvania, and owners are responsible for testing and treating their own water.

For this study, USGS scientists compiled data collected between 1969 and 2007 from industrial, public, and private wells. Arsenic levels, along with other groundwater quality and environmental factors, were used to generate statewide and regional maps that predict the probability of elevated arsenic. The study examined groundwater from carbonate, crystalline, and shale/sandstone bedrock aquifers, and from shallow glacial sediment aquifers. Similar maps have been produced for other states.

"This research is not intended to predict arsenic levels for individual wells; its purpose is to predict the probability of elevated levels of arsenic in groundwater to help public health efforts in Pennsylvania," said USGS scientist Eliza Gross, who led the study. "The study results and associated probability maps provide water-resource managers and health officials with useful data as they consider management actions in areas where groundwater is most likely to contain elevated levels of arsenic."

The Pennsylvania Department of Health plans to use the maps as an educational tool to inform health professionals and citizens of the Commonwealth about the possibility of elevated arsenic in drinking water wells and to help improve the health of residents, particularly in rural communities.

Arsenic occurs naturally and, in Pennsylvania, is most common in shallow glacial and shale/sandstone type aquifers, particularly those containing pyrite minerals. Arsenic can also result from human activities. Geologic conditions, such as fractures, and chemical factors in groundwater, such as low oxygen, extreme pH, and salinity, can cause arsenic to leach from rocks, become mobile, and contaminate wells distant from the source. Groundwater with elevated arsenic levels – more than 4 micrograms per liter -- can be found in scattered locations throughout Pennsylvania.

Arsenic in drinking water has been linked to several types of cancer, reproductive problems, diabetes, a weakened immune system, and developmental delays in children. Arsenic can be reduced or eliminated in tap water through treatment.

Private well owners can find testing and other information on Pennsylvania Department of Environmental Protection Arsenic in Drinking Water website.

Piceance Basin Water-Quality Reports Now Available

OC_Web@usgs.gov (Office of Communications and Publishing) — Tue, 16 Apr 2013 11:26:59 EDT

More than 50 years of water-quality data in the Piceance Basin are now available from the U.S. Geological Survey in two new reports.

The need for this baseline water-resources assessment was identified by energy producers and local governments to address concerns regarding potential changes to surface-water and groundwater resources as large-scale energy development and population growth occurs in the Piceance Basin. Data from 1,545 wells collected from1946 through 2009 were compiled, evaluated, and compared with U.S. Environmental Protection Agency (EPA) drinking-water standards, and are published in a USGS groundwater quality report, available online. Additionally, 347 surface-water sites were compared to EPA drinking-water and Colorado State standards, and are contained in a separate surface-water report.

Groundwater findings include:

Recharge—the downward movement of surface water to groundwater—to most wells was derived from precipitation.
Dissolved-solids concentrations commonly exceeded the EPA secondary drinking-water standard. Dissolved solids consist of minerals, organic matter, and nutrients that have dissolved in water. The major components of dissolved solids of natural waters include bicarbonate, calcium, sulfate, hydrogen, silica, chlorine, magnesium, sodium, potassium, nitrogen, and phosphorus in the form of phosphate.
Arsenic concentrations were higher in low oxygen groundwater and likely from naturally occurring rock.
Nitrate levels likely associated with septic systems, animal manure, or fertilizer.
The majority of methane detections were found near the Mamm Creek-Divide Creek area.

Surface-water findings include:

Salinity and selenium concentrations and loads—a primary concern for water managers in the Lower Gunnison River basin—are generally trending downward.
Approximately 30 percent of phosphorus samples exceeded EPA’s recommended standard.
Overall results varied by site.

“Data gaps were identified and suggestions provided to develop long-term regional-scale monitoring strategies to fill data gaps, minimize information redundancies, and to assist managers in making informed decisions regarding land and water resources,” said David Brown, Western Colorado Office Chief for the USGS Colorado Water Science Center.

This voluntary effort between energy producers and local, state, and federal agencies inventoried existing water resources in the Piceance Basin. The resulting data repository is the most comprehensive collection of Piceance Basin water-quality sampling information available in a single location.

The USGS studies were done in cooperation with (in alphabetical order): Antero Resources; Bureau of Land Management; Bureau of Reclamation; Chevron Corporation; Cities of Grand Junction and Rifle, Colo.; Colorado Department of Agriculture; Colorado Department of Natural Resources; Colorado Department of Public Health and Environment; Colorado Division of Wildlife—River Watch; Colorado Oil and Gas Conservation Commission; Colorado River Water Conservation District; Counties of Delta, Garfield, and Rio Blanco, Colo.; EnCana Oil & Gas (USA) Inc.; Gunnison Energy Corp.; National Park Service; Natural Soda, Inc.; North Fork River Improvement Association; Oxy Petroleum Corporation; Petroleum Development Corp.; Shell Oil Company; Solvay Chemicals; Towns of Carbondale, De Beque, Palisade, Parachute, Rangely, and Silt, Colo.; U.S. Forest Service; West Divide Water Conservancy District; and Williams Companies, Inc.

New Sea-Level-Rise Modeling Forecasts Major Climate Impact to Low-Lying Pacific Islands

OC_Web@usgs.gov (Office of Communications and Publishing) — Thu, 11 Apr 2013 12:00:00 EDT

SANTA CRUZ, Calif. — Dynamic modeling of sea-level rise, which takes storm wind and wave action into account, paints a much graver picture for some low-lying Pacific islands under climate-change scenarios than the passive computer modeling used in earlier research, according to a new U.S. Geological Survey report.

A team led by research oceanographer Curt Storlazzi of the USGS Pacific Coastal and Marine Science Center compared passive "bathtub" inundation models with dynamic models for two of the Northwestern Hawaiian Islands in the Papahānaumokuākea Marine National Monument. The team studied Midway, a classic atoll with islands on the shallow (2–8 meters or 6–26 feet deep) atoll rim and a deep, central lagoon, and Laysan, which is higher, with a 20–30 meter (65–98 feet) deep rim and an island in the center of the atoll. Together, the two locations exhibit landforms and coastal features common to many Pacific islands. Managed by the U.S. Fish and Wildlife Service, they are also among the world’s most important nesting and breeding sites for migratory birds and other wildlife.

"Passive 'bathtub' inundation models typically used to forecast sea-level rise impacts suggest that most of the low-lying atolls in the Pacific Islands will still be above sea level for the next 50-150 years. By taking wave-driven processes into account, we forecast that many of the atolls will be inundated, contaminating freshwater supplies and thus making the islands uninhabitable, much sooner," Storlazzi said.

The team found that at least twice as much land is forecast to be inundated on Midway and Laysan by sea-level rise than was projected by passive models. For example, 91 percent of Midway's Eastern Island is projected to be inundated under a model that takes into account storm and wave activity accompanied by a sea-level rise of 2 meters (6.5 feet), as compared with only 19 percent under passive sea-level-rise models. Storm waves on Midway are also projected to be three to four times higher than they are today, because more deep-water wave energy could propagate over the atoll rim and larger wind-driven waves could develop on the atoll.

"This report demonstrates the future threat to refuges with the Monument, and the potential impact on nesting seabirds, endangered monk seals and green sea turtles will be considered as we plan for the future," said Doug Staller, the Service's Superintendent of the Papahānaumokuākea Marine National Monument.

These findings have importance not only for island wildlife on the largely uninhabited Northwestern Hawaiian Islands, Storlazzi said, but for the tens of thousands of people who live on other low-lying Pacific Island groups such as those found in the Republic of the Marshall Islands and the Federated States of Micronesia. Because the models attempt to characterize how much land will be washed over by storm waves even if it is not permanently inundated, they offer tools for forecasting where agricultural land may be damaged by repeated saltwater overwash, as well as where groundwater may be contaminated by saltwater. The findings suggest that inundation and impacts to infrastructure and terrestrial habitats will occur at lower values of predicted sea-level rise, and thus sooner in the 21st century, than suggested by passive map-based "bathtub" inundation models.

The report, "Forecasting the Impact of Storm Waves and Sea-Level Rise on Midway Atoll and Laysan Island within the Papahānaumokuākea Marine National Monument—A Comparison of Passive Versus Dynamic Inundation Models," is available online.

USGS to Receive New Great Lakes Research Vessel

OC_Web@usgs.gov (Office of Communications and Publishing) — Thu, 11 Apr 2013 10:00:00 EDT

Ann Arbor, Mich. – The U.S. Geological Survey awarded a contract last Friday for the construction of a large research vessel for Lakes Huron, Michigan, and Superior to Burger Boat Company of Manitowoc, Wis.

The vessel will replace the 38-year-old Grayling, bringing the USGS Great Lakes Science Center (GLSC) large vessel fleet up-to-date. The new Grayling will be stationed at the USGS base in Cheboygan, Mich., and will incorporate modern marine standards and state-of-the-art technology to more safely and effectively conduct fisheries research.

"I am delighted to have achieved this important milestone that will benefit the Great Lakes region for many decades," said USGS GLSC Director Russell Strach. "This investment would not have been possible without the support from many key partners. The new research vessel will come fully equipped with 21^st century laboratories and scientific instrumentation to support fishery science for the Great Lakes."

The funding for this expenditure was accrued from two prior appropriations and held in an account that was not affected by the sequester.

The replacement vessel is expected to be a commercial grade 78-foot vessel, and will be designed and constructed for a 40 to 50-year service life. This vessel will be capable of performing critical scientific and mission-related tasks, including dragging nets along the lake bottom, catching fish, and using sound-waves to detect fish and assess their abundance.

"The entire Burger team is very excited to be awarded this significant contract," said Jim Ruffolo, President and CEO of Burger Boat Company. "The Grayling will further reinforce Burger’s commitment to designing and constructing quality vessels that meet each owner’s specific requirements, whether they are custom yachts or commercial vessels."

This new contract will create additional highly skilled shipbuilding jobs at the Manitowoc shipyard, and the project will help support numerous companies that supply raw materials and equipment for the project.

For over 50 years the USGS GLSC has operated a unique and valuable deepwater fish ecology and assessment program that is the foundation for fisheries management throughout the Great Lakes.

Burger, at 150 years old, is one of the world's oldest shipyards. From its facility in Manitowoc, Wis., Burger's craftsmen have built hundreds of high quality vessels as long as 260 feet (80 meters) that can be found in ports around the world. Today, Burger continues its legacy of designing and building vessels to the highest standard from its fully updated shipyard.

JMS Naval Architects of Mystic, Conn., developed the preliminary design of the new Grayling.

The USGS GLSC maintains a fleet of fishery research vessels on each of the Great Lakes to meet the scientific research needs of state, tribal, and federal resource managers for understanding and effectively managing the Great Lakes fishery.

For more information on the USGS GLSC, visit their website.