Rodney R Knight
Biography
Rodney began his career with the USGS in 1992 as a student in the Nashville field office. Upon finishing his degree (Bachelor of Science, Civil / Environmental Engineering, Tennessee Technological University), Rodney returned to the USGS and has worked on a variety projects and programs during his 28-year career. His early-career work included working with the Lower Tennessee River NAWQA team in a variety of roles as well as directing local projects with state partners on developing a program focused on ecological-flow analysis in the Tennessee River basin. These afforded him the opportunity to begin partnering with other states in the Lower Mississippi-Gulf footprint to bring USGS science interests to the table, particularly in the context of ecological flow. Through these efforts, the USGS has been funded through 2025 to evaluate freshwater inflows to the Gulf of Mexico across the 5 Gulf States and develop decision-support frameworks capable of incorporating ecological outcomes for 3 major river basins.
Along the way, Rodney collaborated with EPA Headquarters on the development of a Report to Congress, was an expert witness in a federal trial, and participated in a Powell Center workgroup focused on estimating water availability. Over the last several years, Rodney has enjoyed meeting with a variety of Federal, state, and local partners to develop partnerships and to help connect USGS science and data to real-world needs.
As Center Director for the Lower Mississippi-Gulf WSC, Rodney leads and manages a Center with almost 200 people on staff to provide high-quality water data, interpretations, and visualizations for federal, state, tribal, local and non-governmental agencies and further the mission of the USGS. Being a Director of a Center with a 5-state footprint (Alabama, Arkansas, Louisiana, Mississippi, and Tennessee) requires him to develop and maintain an understanding of the scientific interests and needs of partner agencies, quite often extending beyond that of a single partner agency. Many times, this affords the opportunity to bring together different agencies from neighboring states to focus on a topic of common interest.
Science and Products
Tennessee FloodWatch
Tennessee FloodWatch Information
Streamflow Alteration Assessments to Support Bay and Estuary Restoration in Gulf States
Human alteration of waterways has impacted the minimum and maximum streamflows in more than 86% of monitored streams nationally and may be the primary cause for ecological impairment in river and stream ecosystems. Restoration of freshwater inflows can positively affect shellfish, fisheries, habitat, and water quality in streams, rivers, and estuaries. Increasingly, state and local decision-...
Lower Tennessee River (LTEN) Basin Study
Welcome....the Lower Tennessee River Basin in Tennessee, Alabama, Georgia, Kentucky, and Mississippi is one of the 59 study units that are part of the U.S. Geological Survey's National Water-Quality Assessment (NAWQA) Program.The long-term goals of this program are to describe the status and trends in the quality of a large, representative part of the Nation's surface- and ground-water...
Water availability for ungauged rivers: an integrative, multi-model approach to estimate water availability at ungauged rivers across the United States
There has been increasing attention placed on the need for water availability information at ungauged locations, particularly related to balancing human and ecological needs for water. Critical to assessing water availability is the necessity for daily streamflow time series; however, most of the rivers in the United States are ungauged. This proposal leverages over $1M currently allocated to...
Environmental Flow Research in the Tennessee River Basin
The objective of this project is to improve understanding of how alteration of streamflow characteristics affects the ecological health of rivers and streams in Tennessee. Initial efforts are aimed at identifying critical streamflow characteristics and providing a set of statistical tools and analytical approaches for the prediction of these characteristics. Application of these tools will...
Mississippi Delta Management Systems Evaluation Areas (MDMSEA)
The Mississippi Delta Management Systems Evaluation Areas (MDMSEA) Project began in 1995 with two purposes: 1) to assess how agricultural activities affect water quality; and 2) to evaluate Best Management Practices (BMPs) that mitigate agricultural nonpoint source pollution. The project is located in the northwestern portion of Mississippi, an area of intense agriculture referred to as the...
Streamflow and fish community diversity data for use in developing ecological limit functions for the Cumberland Plateau, northeastern Middle Tennessee and southwestern Kentucky, 2016
Information contained within this dataset represents values of basin characteristics (see Table II in Knight and others, 2012), estimates of streamflow characteristics, measures of individual and cumulative departure of streamflow characteristics from reference hydrologic conditions, and fish species richness for 138 sites in the study area.
An analysis of streamflow trends in the southern and southeastern US from 1950-2015
In this article, the mean daily streamflow at 139 streamflow-gaging stations (sites) in the southern and southeastern United States are analyzed for spatial and temporal patterns. One hundred and thirty-nine individual time-series of mean daily streamflow were reduced to five aggregated time series of Z scores for clusters of sites with similar...
Rodgers, Kirk D.; Roland II, Victor L.; Hoos, Anne B.; Crowley-Ornelas, Elena; Knight, RodneySpecies richness responses to water withdrawal scenarios and minimum flow levels: Evaluating presumptive standards in the Tennessee and Cumberland River basins
Water resource managers are challenged to balance growing water demand with protecting aquatic ecosystems and biodiversity. Management decisions can benefit from improved understanding of water withdrawal impacts on hydrologic regimes and ecological assemblages. This study used Ecological Limit Functions for fish groups within the Tennessee and...
Driver, Lucas; Cartwright, Jennifer M.; Knight, Rodney; Wolfe, William J.Copula theory as a generalized framework for flow-duration curve-based streamflow estimates in ungaged and partially gaged catchments
Flow‐duration curve (FDC) based streamflow estimation methods involve estimating an FDC at an ungaged or partially gaged location and using the time series of nonexceedance probabilities estimated from donor streamgage sites to generate estimates of streamflow. We develop a mathematical framework to illustrate the connection between copulas and...
Worland, Scott C.; Steinschneider, Scott; Farmer, William; Asquith, William H.; White, RodneyPrediction and inference of flow-duration curves using multi-output neural networks
We develop multi-output neural network models (MNNs) to predict flow-duration curves (FDCs) in 9,203 ungaged locations in the Southeastern United States for six decades between 1950-2009. The model architecture contains multiple response variables in the output layer that correspond to individual quantiles along the FDC. During training,...
Worland, Scott C.; Steinschneider, Scott; Asquith, William H.; Knight, Rodney; Wieczorek, Michael E.Streamflow characteristics from modelled runoff time series: Importance of calibration criteria selection
Ecologically relevant streamflow characteristics (SFCs) of ungauged catchments are often estimated from simulated runoff of hydrologic models that were originally calibrated on gauged catchments. However, SFC estimates of the gauged donor catchments and subsequently the ungauged catchments can be substantially uncertain when models are calibrated...
Poole, Sandra; Vis, Marc; Knight, Rodney; Seibert, JanPutting flow-ecology relationships into practice: A decision-support system to assess fish community response to water-management scenarios
This paper presents a conceptual framework to operationalize flow–ecology relationships into decision-support systems of practical use to water-resource managers, who are commonly tasked with balancing multiple competing socioeconomic and environmental priorities. We illustrate this framework with a case study, whereby fish community responses to...
Cartwright, Jennifer M.; Caldwell, Casey; Nebiker, Steven; Knight, RodneyModel calibration criteria for estimating ecological flow characteristics
Quantification of streamflow characteristics in ungauged catchments remains a challenge. Hydrological modeling is often used to derive flow time series and to calculate streamflow characteristics for subsequent applications that may differ from those envisioned by the modelers. While the estimation of model parameters for ungauged catchments is a...
Breuer, Lutz; Kraft, Philipp; Vis, Marc; Knight, Rodney; Poole, Sandra; Wolfe, William J.; Seibert, JanAccelerating advances in continental domain hydrologic modeling
In the past, hydrologic modeling of surface water resources has mainly focused on simulating the hydrologic cycle at local to regional catchment modeling domains. There now exists a level of maturity among the catchment, global water security, and land surface modeling communities such that these communities are converging toward continental...
Archfield, Stacey A.; Clark, Martyn; Arheimer, Berit; Hay, Lauren E.; McMillan, Hilary; Kiang, Julie E.; Seibert, Jan; Hakala, Kirsti; Bock, Andrew R.; Wagener, Thorsten; Farmer, William H.; Andreassian, Vazken; Attinger, Sabine; Viglione, Alberto; Knight, Rodney; Markstrom, Steven L.; Over, Thomas M.Evaluation of statistical and rainfall-runoff models for predicting historical daily streamflow time series in the Des Moines and Iowa River watersheds
Daily records of streamflow are essential to understanding hydrologic systems and managing the interactions between human and natural systems. Many watersheds and locations lack streamgages to provide accurate and reliable records of daily streamflow. In such ungaged watersheds, statistical tools and rainfall-runoff models are used to estimate...
Farmer, William H.; Knight, Rodney R.; Eash, David A.; Kasey J. Hutchinson; Linhart, S. Mike; Christiansen, Daniel E.; Archfield, Stacey A.; Over, Thomas M.; Kiang, Julie E.Hydrologic data for the Obed River watershed, Tennessee
The Obed River watershed drains a 520-square-mile area of the Cumberland Plateau physiographic region in the Tennessee River basin. The watershed is underlain by conglomerate, sandstone, and shale of Pennsylvanian age, which overlie Mississippian-age limestone. The larger creeks and rivers of the Obed River system have eroded gorges through the...
Knight, Rodney R.; Wolfe, William J.; Law, George S.Ecological limit functions relating fish community response to hydrologic departures of the ecological flow regime in the Tennessee River basin, United States
Ecological limit functions relating streamflow and aquatic ecosystems remain elusive despite decades of research. We investigated functional relationships between species richness and changes in streamflow characteristics at 662 fish sampling sites in the Tennessee River basin. Our approach included the following: (1) a brief summary of relevant...
Knight, Rodney R.; Murphy, Jennifer C.; Wolfe, William J.; Saylor, Charles F.; Wales, Amy K.Predicting ecological flow regime at ungaged sites: A comparison of methods
Nineteen ecologically relevant streamflow characteristics were estimated using published rainfall–runoff and regional regression models for six sites with observed daily streamflow records in Kentucky. The regional regression model produced median estimates closer to the observed median for all but two characteristics. The variability of...
Murphy, Jennifer C.; Knight, Rodney R.; Wolfe, William J.; Gain, W. Scott