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Elizabeth Ahearn

Elizabeth Ahearn is a Hydrologist in the New England Water Science Center.

Science and Products

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Installing real-time equipment onto a groundwater well

Developing Synthetic Historical Record at Groundwater Wells Using Record Extension Techniques

The Groundwater Index in the Massachusetts Drought Management Plan provides a general overview of groundwater levels relative to long-term groundwater levels in Massachusetts. The methods used to compute the Groundwater Index were revised for the 2019 version of the Drought Management Plan. The 2019 plan aligns the drought categories and specifies the drought status from select percentile ranges...
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New England Water Science Center
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Developing Synthetic Historical Record at Groundwater Wells Using Record Extension Techniques

The Groundwater Index in the Massachusetts Drought Management Plan provides a general overview of groundwater levels relative to long-term groundwater levels in Massachusetts. The methods used to compute the Groundwater Index were revised for the 2019 version of the Drought Management Plan. The 2019 plan aligns the drought categories and specifies the drought status from select percentile ranges...
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Screenshot of the Flood Insurance Map

Development of Flood Insurance Maps in New England

FEMA has requested USGS expertise in hydraulics, hydrology, and mapping to generate flood insurance maps for New England.
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New England Water Science Center
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Development of Flood Insurance Maps in New England

FEMA has requested USGS expertise in hydraulics, hydrology, and mapping to generate flood insurance maps for New England.
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Flooding in Soldier Pond, Maine

Development of Regional Regression Equations in Connecticut

Knowledge of the magnitude and frequency of floods is needed for the effective and safe design of bridges, culverts, and other structures. This information is also important for flood-plain planning and management. Periodic examination of flood-frequency characteristics is essential to ensure the best estimates of flood magnitudes for a given annual exceedance probabilities (AEP).
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New England Water Science Center
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Development of Regional Regression Equations in Connecticut

Knowledge of the magnitude and frequency of floods is needed for the effective and safe design of bridges, culverts, and other structures. This information is also important for flood-plain planning and management. Periodic examination of flood-frequency characteristics is essential to ensure the best estimates of flood magnitudes for a given annual exceedance probabilities (AEP).
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Filter Total Items: 15

Estimating flood magnitude and frequency on streams and rivers in Connecticut, based on data through water year 2015

The U.S. Geological Survey, in cooperation with the Connecticut Department of Transportation, updated flood-frequency estimates with 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities (2-, 5-, 10-, 25-, 50-, 100-, 200-, and 500-year recurrence intervals, respectively) for 141 streamgages in Connecticut and 11 streamgages in adjacent States using annual peak-flow data
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Water Resources Mission Area, New England Water Science Center

Methods for estimating regional coefficient of skewness for unregulated streams in New England, based on data through water year 2011

The magnitude of annual exceedance probability floods is greatly affected by the coefficient of skewness (skew) of the annual peak flows at a streamgage. Standard flood frequency methods recommend weighting the station skew with a regional skew to better represent regional and stable conditions. This study presents an updated analysis of a regional skew for New England developed using a robust Bay
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Water Resources Mission Area

Flood inundation maps and water-surface profiles for tropical storm Irene and selected annual exceedance probability floods for Flint Brook and the Third Branch White River in Roxbury, Vermont

Flint Brook, a tributary to the Third Branch White River in Roxbury, Vermont, has a history of flooding the Vermont Fish and Wildlife Department’s Roxbury Fish Culture Station (the hatchery) and surrounding infrastructure. Flooding resulting from tropical storm Irene on August 28–29, 2011, caused widespread destruction in the region, including extensive and costly damages to the State-owned hatche
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New England Water Science Center

Nutrient concentrations and loads in the northeastern United States - Status and trends, 1975-2003

The U.S. Geological Survey (USGS) National Water-Quality Assessment Program (NAWQA) began regional studies in 2003 to synthesize information on nutrient concentrations, trends, stream loads, and sources. In the northeastern United States, a study area that extends from Maine to central Virginia, nutrient data were evaluated for 130 USGS water-quality monitoring stations. Nutrient data were analyze
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New England Water Science Center

Magnitude of flood flows for selected annual exceedance probabilities in Rhode Island through 2010

Heavy persistent rains from late February through March 2010 caused severe widespread flooding in Rhode Island that set or nearly set record flows and water levels at many long-term streamgages in the State. In response, the U.S. Geological Survey, in partnership with the Federal Emergency Management Agency, conducted a study to update estimates of flood magnitudes at streamgages and regional equa
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New England Water Science Center, StreamStats

USGS library for S-PLUS for Windows -- Release 4.0

Release 4.0 of the U.S. Geological Survey S-PLUS library supercedes release 2.1. It comprises functions, dialogs, and datasets used in the U.S. Geological Survey for the analysis of water-resources data. This version does not contain ESTREND, which was in version 2.1. See Release 2.1 for information and access to that version. This library requires Release 8.1 or later of S-PLUS for Windows. S-PL
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Water Resources Mission Area, Upper Midwest Environmental Sciences Center, Upper Midwest Water Science Center

Connecticut Highlands technical report— Documentation of the regional rainfall-runoff model

This report provides the supporting data and describes the data sources, methodologies, and assumptions used in the assessment of existing and potential water resources of the Highlands of Connecticut and Pennsylvania (referred to herein as the “Highlands”). Included in this report are Highlands groundwater and surface-water use data and the methods of data compilation. Annual mean streamflow and
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New England Water Science Center

Regional Regression Equations to Estimate Flow-Duration Statistics at Ungaged Stream Sites in Connecticut

Multiple linear regression equations for determining flow-duration statistics were developed to estimate select flow exceedances ranging from 25- to 99-percent for six 'bioperiods'-Salmonid Spawning (November), Overwinter (December-February), Habitat Forming (March-April), Clupeid Spawning (May), Resident Spawning (June), and Rearing and Growth (July-October)-in Connecticut. Regression equations a
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New England Water Science Center

Flood of April 2007 and Flood-Frequency Estimates at Streamflow-Gaging Stations in Western Connecticut

A spring nor'easter affected the East Coast of the United States from April 15 to 18, 2007. In Connecticut, rainfall varied from 3 inches to more than 7 inches. The combined effects of heavy rainfall over a short duration, high winds, and high tides led to widespread flooding, storm damage, power outages, evacuations, and disruptions to traffic and commerce. The storm caused at least 18 fatalities
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New England Water Science Center

Flow Durations, Low-Flow Frequencies, and Monthly Median Flows for Selected Streams in Connecticut through 2005

Flow durations, low-flow frequencies, and monthly median streamflows were computed for 91 continuous-record, streamflow-gaging stations in Connecticut with 10 or more years of record. Flow durations include the 99-, 98-, 97-, 95-, 90-, 85-, 80-, 75-, 70-, 60-, 50-, 40-, 30-, 25-, 20-, 10-, 5-, and 1-percent exceedances. Low-flow frequencies include the 7-day, 10-year (7Q10) low flow; 7-day, 2-year
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New England Water Science Center

Streamstats: U.S. Geological Survey web application for streamflow statistics for Connecticut

Introduction An important mission of the U. S. Geological Survey (USGS) is to provide information on streamflow in the Nation's rivers. Streamflow statistics are used by water managers, engineers, scientists, and others to protect people and property during floods and droughts, and to manage land, water, and biological resources. Common uses for streamflow statistics include dam, bridge, and cu
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New England Water Science Center, StreamStats

Estimates of the magnitude and frequency of flood flows in the Connecticut River in Connecticut

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