Plenary Presentations
Representation of hydrology, erosion, and transport processes in the SWAT+ watershed model
Dr. Jeff Arnold, USDA-ARS Temple, Texas, jeff.arnold@usda.gov
SWAT+ is a completely restructured version of the Soil and Water Assessment Tool (SWAT) that was developed to face present and future challenges in water resources modeling and management. SWAT+ is considerably more flexible than SWAT regarding watershed discretization and configuration. HRUs, aquifers, channels, reservoirs, ponds, wetlands, and point sources and inlets are separate spatial objects, whose hydrologic interaction can be defined by the user to represent the physical characteristics of a watershed as realistically as possible. Hydrological, sediment, and pesticide fate and transport processes as simulated in SWAT+ are discussed. Different options for configuring wetlands within the landscape, including riparian wetlands and potholes, are demonstrated.
VFS Effectiveness to Mitigate Pesticides: Mechanistic Analysis with VFSMOD
Rafael Muñoz-Carpena, Agricultural and Biological Engineering, University of Florida, carpena@ufl.edu
Pesticides high-tier, long-term environmental risk assessments (ERA) are based on the combination of complicated mechanistic models to evaluate regulatory compliance. The modeling framework often involves large sets of input factors (model parameters, initial and boundary conditions, and other model structure options). How can we identify the relative importance of human, chemical, physical and biological drivers on the assessment results? Is there a case for “the right answers for the right reasons”? For the case of pesticide mitigation practices like vegetative filter strips (VFS) for runoff mitigation, what are the important factors controlling or limiting their efficiency under different field settings? We evaluate the combination of the current ERA frameworks (US EPA PWC and EU FOCUS SWAN) in combination with VFSMOD, an established and commonly used numerical model for the analysis of runoff, sediment, and pesticide transport in VFS. We present a systematic study of the importance of different field conditions that have been proposed in the past as limiting the efficiency of VFS in realistic settings: flow concentration (channelization) through the filter, timing of pesticide application compared to other drivers, assumptions about the degradation and remobilization of pesticide trapped in the filter between runoff events, seasonal presence of a shallow water table near the receiving water body. We identify instances in which the importance commonly assigned to these factors is not supported by the mechanistic analysis, where other factors different than those proposed largely control the results of the assessments.
Assessment Tools and Mitigation Methods for Contaminant Losses to Wetlands – An NRCS Perspective
Chris Coreil, USDA-NRCS National Erosion Specialist, chris.coreil@usda.gov
The USDA Natural Resources Conservation Service (NRCS) employs a variety of technical tools to assess the potential for off-site movement of pesticides, nutrients, and sediment. If the potential for off-site movement exceeds a planning threshold value for sustainability or productivity, then it is identified as a resource concern and conservation practices are recommended to address the resource concern. The Conservation Assessment and Ranking Tool (CART) is the newly adopted platform that allows NRCS conservation planners to conduct high level resource assessments for soil, water, air, plant, animal, and energy resources. This tool is designed to take advantage of geospatial resources where possible, thus minimizing data input by conservation planners. CART functions by setting a site-specific planning threshold for individual resource concerns based on site vulnerability. This evaluation includes soils and climate information as well as site-specific conservation planner inputs for high level management and conservation practices that have already been applied. The mitigation value of existing management and conservation practices is compared to the site-specific planning thresholds to see if more conservation is needed to address a site’s inherent vulnerability. Since CART was adopted in 2020, and still undergoing significant modifications, NRCS still relies on several stand-alone assessment tools if overrides are necessary. Once conservation practices are selected, stand-alone assessment tools are also used to develop site-specific producer implementation requirements. Typical stand-alone tools used, both for CART overrides and implementation requirement development, include the Windows Pesticide Screening Tool (WIN-PST), Revised Universal Soil Loss Equation (RUSLE2), Water Erosion Prediction Project (WEPP), Wind Erosion Prediction System (WEPS), Web Soil Survey, Stewardship Tool for Environmental Performance (STEP), and state phosphorus indices. This new NRCS high-level assessment process, typical conservation practices selected to reduce contaminant losses, and stand-alone assessment tools will be discussed.
What does the future of hydrologic/water quality modeling hold?
Bernie Engel, Associate Dean for Agricultural Research and Graduate Education and Professor of Agricultural and Biological Engineering, Purdue University, engelb@purdue.edu
This presentation will explore the future of hydrologic/water quality modeling. Several ongoing trends are likely to have significant impacts on the future of hydrologic/water quality modeling. Researchers are developing hydrologic/water quality models that improve representations of processes and interactions among processes. This improved representations in many cases require additional computational resources as well as new or additional data. Data to support models are increasingly available and will continue to improve in both temporal and spatial resolutions. Sensors will continue to become more prominent and flow data in real time that support models as well. Types of data that have been unavailable, greatly limited in availability, or prohibitively expensive will be increasingly available. Data science and associated efforts that include artificial intelligence, machine learning, databases and optimization approaches will be increasing used with models to improve location specific application of models. Computational capabilities are continuing to advance rapidly and have become ubiquitous with cloud computing.
State-of-the-science on hydrology and erosion: How are these processes represented in a widely used soil erosion model?
Dr. Dennis C. Flanagan, USDA-ARS Research Agricultural Engineer, Dennis.Flanagan@usda.gov
Soil erosion by water is a serious problem nationally and internationally, as are the impacts of runoff, sediment, and pollutants transported off of agricultural and forested lands that enter ditches, streams, lakes, and other water bodies. Existing erosion prediction methods based upon the Universal Soil Loss Equation and its revisions are adequate for long-term average annual soil erosion estimation, but inadequate for more comprehensive hydrologic and erosion assessments. In particular they do not provide other information, including runoff generation, temporal and spatial soil loss, sediment delivery, return-period analyses, or the ability to conduct risk assessments. To address these needs, USDA has created a process-based computer simulation model that simulates the important physical processes that drive and affect soil loss: the Water Erosion Prediction Project (WEPP) model. WEPP can be applied to both small hillslope profiles within fields (similar to the USLE), as well as to combinations of hillslopes, channels, and impoundments in small watersheds. Since its initial release in 1995 the model has been extensively applied, especially by the Forest Service for assessment of erosion risks from areas burned by wildfires. The Natural Resources Conservation Service is preparing to implement WEPP for use by its field office staff and technical service providers for soil conservation planning activities. This presentation will provide information on how WEPP represents the hydrologic processes of rainfall, infiltration, and runoff, and the erosion processes of detachment by raindrops, detachment by flow, sediment transport, and sediment deposition. Status of WEPP, interfaces, databases, applications and current development efforts will also be briefly discussed.
Wetland Species Risk Assessment - An Industry Perspective
Patrick L Havens, PhD, Corteva AgriScience Laureate, pat.havens@corteva.com
Eric J. Henry, Ph.D., Environmental Fate group at BASF, eric.henry@basf.com
Mark Anthony Thomas, Ph.D., Regulatory Science, Bayer Crop Science, mark.thomas2@bayer.com
EPA Modeling Approaches for Wetland Plants
James (Trip) Hook III, Ecologist, US EPA Office of Pesticide Programs, Hook.James@epa.gov
Privately-Owned Wetlands Improve Water Quality in the Mid-South
Scott W. Manley, Ph.D., Director of Conservation Programs, Mississippi Alluvial Valley, smanley@ducks.org
Novel hydrology and water quality of wetlands in agricultural landscapes
Dr. Sara Winnike-McMillan, PE, Associate Professor of Agricultural and Biological Engineering, Purdue University, smcmillan@purdue.edu
Wetlands are novel ecosystems in the agricultural landscape. They provide critical habitat for a host of diverse species, filter nutrients and pollutants from upland fields, and buffer hydrologic extremes. Wetlands occupy low positions in landscape and drain water from surrounding fields. Because of the tight coupling of surface and groundwater, they have the capacity to mediate and store flow during storms as well as raise groundwater tables during periods of drought. Agricultural water management through an ever-increasing system of drainage tiles and channels threatens this function and disrupts the capacity for water storage. Fertilizers and agronomic chemicals that are applied to farm fields flow into these wetlands. While they have a great capacity to buffer agricultural inputs, the few remaining wetlands throughout the Midwest do not match the scale at which they are needed. This talk will link historic function of wetland ecosystems to current efforts to restore wetlands in the drained agricultural landscape.
Ecological perspectives on pesticides and other agricultural contaminants within agricultural headwater streams
Dr. Peter (Rocky) C. Smiley, Jr., USDA-ARS Research Ecologist, rocky.smiley@usda.gov
Agricultural runoff containing pesticides, nutrients, and sediment enters headwater streams and wetlands first before being transported downstream to larger streams and rivers. Concentrations of pesticides and other agricultural contaminants within these aquatic habitats located in the upper reaches of agricultural watersheds can periodically exceed the aquatic life benchmarks for aquatic animals and plants. Understanding the spatiotemporal trends in pesticides and other agricultural contaminants and the relationships of the biota with agricultural contaminants within headwater streams and wetlands is needed to develop watershed management strategies to reduce agricultural impacts. My objective for this presentation is to synthesize selected research results documenting the spatiotemporal trends of pesticides and pesticide mixtures, the impacts of conservation practices, and the relationships of aquatic animals with pesticides and other agricultural contaminants within agricultural headwater streams in the Midwestern United States. The research results selected for this presentation will be from research conducted from 2006 to 2015 within agricultural headwater streams in Indiana, Michigan, and Ohio to assess the ecological impacts of conservation practices on the biota as part of the USDA’s Conservation Effects Assessment Project (CEAP). I will use this synthesis to highlight recommendations from an aquatic ecology perspective on how these research findings might guide the development of higher-tier exposure assessment framework and risk mitigation measures for herbicides within agricultural headwater streams in the Midwestern United States.
Restoring Wetland Habitat on Private Lands in Ohio, through the U.S. Fish and Wildlife Service Partners for Fish and Wildlife Program
Lori Stevenson, State Private Lands Coordinator, U.S. Fish and Wildlife Service, lori_stevenson@fws.gov
The U.S. Fish and Wildlife Service Partners for Fish and Wildlife (USFWS – PFW) Program is a national voluntary habitat conservation program designed to work with private landowners and other conservation partners (on non-Federal and non-State-owned properties), to assist them with improving their lands for fish, wildlife and plant species. Through the PFW Program, Lori Stevenson, the State Private Lands Coordinator and her Team of three private lands biologists in Ohio, provide technical and/or cost share financial assistance to facilitate habitat conservation projects on private lands across the Ohio landscape. These habitat conservation projects, which must provide benefit to federal trust resources such as migratory birds, threatened and endangered species, and the critical habitat needed to support these species, can include such habitat conservation practices as wetland, upland/pollinator, in-stream, aquatic species passage, riparian, and early successional habitat restoration/enhancement and/or protection. This presentation will focus on wetland habitat projects conducted through the USFWS PFW Program in Ohio.