Sara is a staff scientist in the Upper Midwest Water Science Center with a focus on surface water hydrology and statistics.
I began working at the USGS in 2007 with a background in surface hydrology and statistics. My recent studies have focused on flood frequency estimation and characterization of changes in magnitude and timing of floods in the midwest. Additional interests and past projects have focused on simulation and statistical modeling of surface water reservoirs, streamflow at ungaged sites, and the effects of human water use on water availability and fish populations.
Education and Certifications
Master of Science, Civil and Environmental Engineering, Tufts University, 2010
Master of Environmental Management, Duke University, 2002
Bachelor of Arts, University of North Carolina, 1997
Science and Products
The Connecticut Streamflow and Sustainable Water Use Estimator: A Decision-Support Tool to Estimate Streamflow and Water Availability at Ungaged, User-Defined Stream Locations in Connecticut
Estimation of Daily Streamflow and Water Availability in the Massachusetts Sustainable-Yield Estimator, Version 2.0
Model archive - Regional regression models for estimating flood frequency characteristics of unregulated streams in Wisconsin
PeakFQ input and output files for 299 streamgages in Wisconsin through water year 2020.
Hydrologic metrics, biological metrics, R scripts, and model archives associated with regression analyses used to quantify relations between altered hydrological and biological responses in rivers of Minnesota, 1945-2015
Attributions for nonstationary peak streamflow records across the conterminous United States, 1941-2015 and 1966-2015
Estimating flood magnitude and frequency for unregulated streams in Wisconsin
Quantifying relations between altered hydrology and fish community responses for streams in Minnesota
Evaluation of uncertainty intervals for daily, statistically derived streamflow estimates at ungaged basins across the continental U.S.
User guide for the Massachusetts Sustainable-Yield Estimator (MA SYE—version 2.0) computer program
Methods used to estimate daily streamflow and water availability in the Massachusetts Sustainable-Yield Estimator version 2.0
User guide for the Connecticut Streamflow and Sustainable Water Use Estimator (CT SSWUE—version 1.0) computer program
The Connecticut Streamflow and Sustainable Water Use Estimator—A decision-support tool to estimate water availability at ungaged stream locations in Connecticut
Characterizing uncertainty in daily streamflow estimates at ungauged locations for the Massachusetts sustainable yield estimator
Effects of water-supply reservoirs on streamflow in Massachusetts
Massachusetts reservoir simulation tool—User’s manual
Hydroclimatic regimes: a distributed water-balance framework for hydrologic assessment, classification, and management
Estimating irrigation water use in the humid eastern United States
Non-USGS Publications**
, and R. M. Lent4
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Hydrologic Model Evaluation and Time-Series Tools (HyMETT) R-package
Massachusetts Sustainable-Yield Estimator (MASYE) application software (version 2.0)
This software release provides the database application that runs the Massachusetts Sustainable-Yield Estimator (MA SYE) computer program (version 2.0).
Connecticut Streamflow and Sustainable Water Use Estimator (CTSSWUE Version 1.0) application software
This software release provides the database application that runs the Connecticut Streamflow and Sustainable Water Use Estimator (CT SSWUE) computer program (version 1.0).
The Massachusetts Reservoir Simulation Tool
The Massachusetts Reservoir Simulation Tool is a screening-level model developed to examine the effects of reservoirs on the natural streamflow of streams in Massachusetts. The Massachusetts Reservoir Simulation Tool simulates the daily water balance equation of a water supply reservoir and estimates the magnitude, frequency and duration of spillage below the dam over the period of record.
Science and Products
- Science
The Connecticut Streamflow and Sustainable Water Use Estimator: A Decision-Support Tool to Estimate Streamflow and Water Availability at Ungaged, User-Defined Stream Locations in Connecticut
The Connecticut streamflow and sustainable water use estimator is a decision-support tool that provides estimates of daily unaltered streamflow, water-use adjusted streamflow (for the portions of the state where water-use data are available), and water availability for ungaged, user-defined sites in Connecticut.Estimation of Daily Streamflow and Water Availability in the Massachusetts Sustainable-Yield Estimator, Version 2.0
The Massachusetts Sustainable-Yield Estimator is a decision-support tool that provides estimates of daily unaltered streamflow, water-use-adjusted streamflow, and water availability for ungaged, user-defined sites in Massachusetts. In this recently completed study, version 2.0 of the original Sustainable-Yield Estimator (Archfield and others, 2010) was developed with minor changes to the... - Data
Model archive - Regional regression models for estimating flood frequency characteristics of unregulated streams in Wisconsin
This model archive contains R source code for the Weighted-Multiple Linear Regression Program (WREG), input files, and associated output files needed to recreate regression models that are discussed in the report: Levin, S.B. and Sanocki, C.A., Methods for estimating flood magnitude and frequency for unregulated streams in Wisconsin, U.S. Geological Survey Scientific Investigations Report 2022-511PeakFQ input and output files for 299 streamgages in Wisconsin through water year 2020.
This dataset includes U.S. Geological Survey (USGS) flood-frequency analysis software PeakFQ input and output files for 299 streamgages in Wisconsin. Input files for each streamgage include peak streamflow data through 2020 and PeakFQ specification files. Output files are text files (.prt) with flood-frequency results.Hydrologic metrics, biological metrics, R scripts, and model archives associated with regression analyses used to quantify relations between altered hydrological and biological responses in rivers of Minnesota, 1945-2015
The U.S. Geological Survey (USGS) and the Minnesota Pollution Control Agency (MPCA) conducted a cooperative study to develop linear regression models that quantify relations among 173 hydrologic explanatory metrics in five categories (duration, frequency, magnitude, rate-of-change, and timing) computed from streamgage records and 132 biological response metrics in six categories (composition, habiAttributions for nonstationary peak streamflow records across the conterminous United States, 1941-2015 and 1966-2015
The U.S. Geological Survey Dakota Water Science Center, in cooperation with the Federal Highway Administration, analyzed annual peak-flow data to determine if trends are present and provide attribution of trends where possible. Work for the national trend attributions for nonstationary annual peak-flow records was broken into seven regions that are loosely based off of two-digit hydrologic unit wa - Publications
Filter Total Items: 18
Estimating flood magnitude and frequency for unregulated streams in Wisconsin
Flood frequency characteristics and estimated flood discharges for the 50-, 20-, 10-, 4-, 2-, 1-, 0.5-, and 0.2-percent annual exceedance probabilities were computed at 299 streamgaged locations in Wisconsin. The State was divided into four flood frequency regions using a cluster analysis to produce regions which are homogeneous with respect to physical basin characteristics. Regression equationsQuantifying relations between altered hydrology and fish community responses for streams in Minnesota
Altered hydrology is a stressor on aquatic life for several streams in Minnesota, but quantitative relations between specific aspects of streamflow alteration and biological responses have not been developed on a statewide scale in Minnesota. Best subsets regression analysis was used to develop linear regression models that quantify relations among five categories of hydrologic explanatory metricEvaluation of uncertainty intervals for daily, statistically derived streamflow estimates at ungaged basins across the continental U.S.
Streamflow estimation methods that transfer information from an index gage to an ungaged site are commonly used; however, uncertainty in daily streamflow estimates are often not adequately quantified. In this study, daily streamflow was simulated at 1,331 validation streamgages across the continental United States using four transfer-based streamflow estimation methods. Empirical 95 percent unceUser guide for the Massachusetts Sustainable-Yield Estimator (MA SYE—version 2.0) computer program
This report is a user guide for the Massachusetts Sustainable-Yield Estimator (MA SYE) computer program (version 2.0). The MA SYE was developed by the U.S. Geological Survey in cooperation with the Massachusetts Department of Environmental Protection to provide a planning-level decision-support tool designed to help decision makers estimate daily mean streamflows and selected streamflow statisticsMethods used to estimate daily streamflow and water availability in the Massachusetts Sustainable-Yield Estimator version 2.0
The Massachusetts Sustainable-Yield Estimator is a decision support tool that provides estimates of daily unaltered streamflow, water-use-adjusted streamflow, and water availability for ungaged, user-defined basins in Massachusetts. Daily streamflow at the ungaged site is estimated for unaltered (no water use) and water-use scenarios. The procedure for estimating streamflow was developed previouslUser guide for the Connecticut Streamflow and Sustainable Water Use Estimator (CT SSWUE—version 1.0) computer program
This report is a user guide for the Connecticut Streamflow and Sustainable Water Use Estimator (CT SSWUE) computer program (version 1.0). The CT SSWUE was developed by the U.S. Geological Survey in cooperation with the Connecticut Department of Energy and Environmental Protection to provide a planning-level decision-support tool designed to help decision makers estimate daily mean streamflows andThe Connecticut Streamflow and Sustainable Water Use Estimator—A decision-support tool to estimate water availability at ungaged stream locations in Connecticut
Freshwater streams in Connecticut are subject to many competing demands, including public water supply; agricultural, commercial, and industrial water use; and ecosystem and habitat needs. In recent years, drought has further stressed Connecticut’s water resources. To sustainably allocate and manage water resources among these competing uses, Federal, State, and local water-resource managers requiCharacterizing uncertainty in daily streamflow estimates at ungauged locations for the Massachusetts sustainable yield estimator
Hydrologic characterization at ungauged locations is one of the quintessential challenges of hydrology. Beyond simulation of historical streamflows, it is similarly important to characterize the level of uncertainty in hydrologic estimates. In tandem with updates to Massachusetts Sustainable Yield Estimator, this work explores the application of global uncertainty estimates to daily streamflow simEffects of water-supply reservoirs on streamflow in Massachusetts
State and local water-resource managers need modeling tools to help them manage and protect water-supply resources for both human consumption and ecological needs. The U.S. Geological Survey, in cooperation with the Massachusetts Department of Environmental Protection, has developed a decision-support tool to estimate the effects of reservoirs on natural streamflow. The Massachusetts Reservoir SimMassachusetts reservoir simulation tool—User’s manual
IntroductionThe U.S. Geological Survey developed the Massachusetts Reservoir Simulation Tool to examine the effects of reservoirs on natural streamflows in Massachusetts by simulating the daily water balance of reservoirs. The simulation tool was developed to assist environmental managers to better manage water withdrawals in reservoirs and to preserve downstream aquatic habitats.Hydroclimatic regimes: a distributed water-balance framework for hydrologic assessment, classification, and management
Runoff-based indicators of terrestrial water availability are appropriate for humid regions, but have tended to limit our basic hydrologic understanding of drylands – the dry-subhumid, semiarid, and arid regions which presently cover nearly half of the global land surface. In response, we introduce an indicator framework that gives equal weight to humid and dryland regions, accounting fully for boEstimating irrigation water use in the humid eastern United States
Accurate accounting of irrigation water use is an important part of the U.S. Geological Survey National Water-Use Information Program and the WaterSMART initiative to help maintain sustainable water resources in the Nation. Irrigation water use in the humid eastern United States is not well characterized because of inadequate reporting and wide variability associated with climate, soils, crops, anNon-USGS Publications**
P. K. Weiskel, D. M. Wolock, P. J. Zarriello, R. M. Vogel, S. B. Levin, 2014: Hydroclimatic regimes: a distributed water-balance framework for hydrologic assessment, classification, and management, Hydrology and Earth Systems Sciences, vol 18.
, and R. M. Lent4Farmer, William H. and Sara Levin, 2018. Characterizing Uncertainty in Daily Streamflow Estimates at Ungauged Locations for the Massachusetts Sustainable Yield Estimator. Journal of the American Water Resources Association (JAWRA) 54(1): 198‐210. https://doi.org/10.1111/1752-1688.12603**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
- Software
Hydrologic Model Evaluation and Time-Series Tools (HyMETT) R-package
Hydrologic Model and Evaluation Time-series Tools (HyMETT) software facilitates the analysis and evaluation of hydrologic model output and time-series data with functions focused on comparison of modeled and observed data, period-of-record statistics, and trends.Massachusetts Sustainable-Yield Estimator (MASYE) application software (version 2.0)
This software release provides the database application that runs the Massachusetts Sustainable-Yield Estimator (MA SYE) computer program (version 2.0).
Connecticut Streamflow and Sustainable Water Use Estimator (CTSSWUE Version 1.0) application software
This software release provides the database application that runs the Connecticut Streamflow and Sustainable Water Use Estimator (CT SSWUE) computer program (version 1.0).
The Massachusetts Reservoir Simulation Tool
The Massachusetts Reservoir Simulation Tool is a screening-level model developed to examine the effects of reservoirs on the natural streamflow of streams in Massachusetts. The Massachusetts Reservoir Simulation Tool simulates the daily water balance equation of a water supply reservoir and estimates the magnitude, frequency and duration of spillage below the dam over the period of record.