Research Project: Science and Technologies for Improving Soil and Water Resources in Agricultural Watersheds

Location: Watershed Physical Processes Research

2024 Annual Report

Objectives
1. Develop technologies to effectively manage surface water and groundwater resources in the Lower Mississippi River Basin. 1.A. Evaluate aquifer storage and recovery (ASR) for increasing groundwater supply in the Lower Mississippi River Basin. 1.B. Develop databases and computer modeling technologies to manage surface and groundwater resources for sustainable irrigated agriculture in the Lower Mississippi River Basin. 2. Develop and improve technologies to conserve soil and effectively manage erosion and sediments for a range of scales including plot, field, channel, and watershed scales. 2.A. Quantify the effects of soil physicochemical, geographic and hydro-climatic conditions, and soil conservation measures on soil erodibility and health. 2.B. Investigate the transport and fate of sediments eroded from farm fields and channels in agricultural watersheds. 2.C. Develop computer model components to improve assessment of soil and sediment management practices from field to watershed scale. 3. Evaluate management impacts on landscape evolution and processes in support of the national CEAP and LTAR networks. 3.A. Evaluate the multi-scale impacts of soil and water conservation practices. 3.B. Contribute databases and models to evaluate the long-term sustainability of agroecosystems. 3.C. Enhance and analyze the Goodwin Creek Experimental Watershed long-term data sets. 3.D. Assess long-term landscape agroecosystem sustainability using geophysical soil characterizations.

Approach
This Research Project addresses: (1) stresses on the Nation’s soil and water resources by increased agricultural water demand, agricultural intensification, and a changing climate; (2) impacts of groundwater withdrawals from the Mississippi River Valley Alluvial Aquifer on the integrity of the regional agroecosystem; and (3) limitations in knowledge and tools to assess management and climatic effects on watershed physical processes at plot, farm, watershed, and river-basin scales. We will use an integrated approach to watershed management through the development and testing of innovative practices and computational models based on scientific understanding of multi-scale hydrogeomorphic processes. Specifically, we will evaluate the feasibility of aquifer storage and recovery to provide reliable groundwater supply for irrigated agriculture on the Mississippi Alluvial Plain, and develop databases and computer modeling tools to assess surface water and groundwater resources management in the region. We will combine field and laboratory, short- and long-term experiments to fill technology and knowledge gaps in USDA erosion models concerning soil erodibility characterization, erosion and control of ephemeral gullies and earthen embankments, and transport and fate of eroded sediments. Long-term research and computer model development will investigate the long-term sustainability of agroecosystems. Project outcomes will provide critical information and tools to federal, state and local agencies to: (1) sustainably manage water resources in the Lower Mississippi River Basin, and (2) reduce soil loss and manage sediment in our Nation’s water bodies.

Progress Report
Under Objective 1 we completed operational testing for a pilot project assessing the feasibility of managed aquifer recharge technology utilizing riverbank filtration and groundwater transfer and injection for the Mississippi River Valley Alluvial Aquifer. An engineering firm conducted an independent review of the pilot project, which concluded that the managed aquifer recharge system is an overall success, and the design and implementation of the system is fit for purpose. The engineering firm’s report further recommends continuing the operation of the pilot system itself and expanding the program using the same overall approach. We have engaged stakeholders to provide science support as they pursue their water management plans to support sustainable agroecosystems in the Delta region of Mississippi. Near the riverbank filtration withdrawal site, we continued to map river bathymetry and flow repeatedly to determine if pumping water near the river affects the hyporheic zone through which water flows to the aquifer. In collaboration with the University of Texas at Arlington, we enhanced a machine-learning methodology and developed post-processing techniques to extract the drainage ditch systems in the Delta region of Mississippi, which was tested for the 12-digit Hydrologic Unit Code sub-watersheds Roundaway Bayou-Quiver River and Beaver Bayou-Mound Bayou. Also, in collaboration with the University of Texas at Arlington, we conducted hydraulic modeling analyses of the Roundaway Bayou-Quiver River sub-watershed to determine appropriate mesh-size for performing basin-scale hydrologic simulations of water resources in the Lower Mississippi River Basin using the Weather Research & Forecasting and Advanced Terrestrial Simulator computer models. Under Objective 2 we completed extensive tests to quantify the hydraulic forces acting on the bottom of the new soil erosion flume, and successfully initiated erosion experiments of fine-grained non-cohesive soils found to optimize flume operation and validate our approach to quantify soil erosion-resistance. We completed repairs to the levee system around an irrigation reservoir at Johnson Farm. For comparative studies, we installed various levee protection measures such as full-scale floating wave barriers and geotextile, completed instrumentation of the field site and an initial survey of the new levee system immediately after it was repaired. Monitoring of weather, waves, and erosion will continue through at least the next several years. We completed analysis and manuscript preparation of the effects of three repeated unsteady flow hydrographs on sediment transport and bed forms for sand-bedded streams. We completed extensive analysis and first round of review process for a manuscript on six unsteady flow hydrographs, repeated three times, with periods of 1-6 hours. Major findings include that repeated hydrographs continued to have counter-clockwise hysteresis in the relationship between transport rate and flow rate and that the Engelund-Hansen method, a predictive equation for total sediment load, was still effective at predicting transport rates based on hydraulic parameters for all lengths of repeated hydrographs. We analyzed all incoming data from the impact plate system installed in the Goodwin Creek Experimental Watershed by establishing a calibration relationship based on physical samples collected concomitantly with impact plate data. To augment this work, we established a slope-study reach just upstream of the structure where the impact plates are mounted. Ten pressure transducers were installed, surveyed with high-precision, and used to monitor water levels and water surface slope just upstream. The water surface slope data enables interpretation of other measurements, such as the gravel transport data generated by the impact plate system. Comparative studies showed RUSLE2 is a stable and consistent conservation planning application for use by USDA-Natural Resource Conservation Service (USDA-NRCS) across the United States. We restructured RUSLE2 technology from a single user desktop application into a cloud service, creating limitless connectivity potential for NRCS conservation managers. In collaboration with the University of Mississippi, we continued the development of modeling capabilities that integrate surface and groundwater processes to predict seasonal patterns in soil moisture to help understand patterns in soil erodibility to predict where and when ephemeral gullies may develop. We developed new GIS-based analysis methods that use high-resolution, spatially oriented surface roughness data to predict runoff patterns for better design of structural soil conservation measures. Under Objective 3 we made progress on adapting the USDA, ARS natural resources computer model AnnAGNPS for application within the University of Mississippi web-based tool, Agricultural Integrated Management System. A topographic analysis was completed for the entire USA as needed for applications of watershed simulations. A beta-version of an on-line user interface provides a critical management tool based on the integrated capabilities of AnnAGNPS to characterize and evaluate water and sheet and rill erosion and sediment yield. This tool provides users with the capabilities to evaluate the impact of land management practices applied within any watershed system throughout the USA to aid in the development of conservation management plans to manage water and erosion. We continued to enhance our 40+-year database comprising precipitation, runoff, sediment transport, land use and management, and channel morphology data at the Goodwin Creek Experimental Watershed to support the national Conservation Effects Assessment Project (CEAP) and Long Term Agroecosystem Research (LTAR) Network. We continued to collect samples of soil, biomass, as well as eddy covariance data as part of the common experiment across LTAR sites. We have three collaborative farmers, which allow us two comparisons of prevailing (PRV) practices versus two comparisons of alternative (ALT) field practices. Of the three farmers, one is owned and operated by a minority farmer in Mound Bayou, MS. A non-assistance cooperative agreement was established with Ohio State University to gap fill and process backlogged eddy covariance data. Cooperators are providing an algorithm to use for future data collection. A cross-site (national) experiment with seven locations completed the first year of data collection to assess phytoplankton algal nutrient limitation and thresholds to determine eutrophication in watersheds with different agricultural land use. The cross-site experiment is currently in its second field season. Several new initiatives within the LTAR Drainage Working Group (microplastics, ecosystem metabolism, and greenhouse gas measurements) were designed and research will be initiated beginning in FY25. One manuscript was submitted and published this FY detailing the common experiment in the Lower Mississippi River Basin LTAR project. Coupling our unmanned aerial system (UAS) collection and analysis of LTAR and other laboratory projects has promoted continual growth and extension of UAS collection and data use.

Accomplishments
1. Assessment of the largest non-volcanic catastrophe in modern times. In February 2020 a 150 meter tall waterfall collapsed on the Rio Coca, Ecuador, which resulted in rapid upstream towards the Coca Coda Sinclair hydroelectric project. Geomorphic adjustment of the Rio Coca represents a highly unusual natural disaster threatening life, property, water quality, the regional economy, major infrastructure, and energy security. ARS researchers at Oxford, Mississippi, cooperated with experts from the United States Army Corps of Engineers, United States Geological Survey, and the Electric Corporation of Ecuador to characterize the geomorphic adjustment of the Rio Coca since the waterfall collapse and the geotechnical properties of the bed and bank materials. In the four years after the collapse of the waterfall, the erosion front migrated almost 14 km upstream, and is within 6 km of the dam. About 500 Mega metric tons of sediment have been removed and transported downstream. The patterns of erosion and deposition resemble those that follow intentional dam removals, but on a scale one to two orders of magnitude larger and with greater complexity in a geologically heterogenous river corridor. The river's boundary materials comprise four erodible geologic units consisting of volcaniclastic and lacustrine deposits that mostly fall within the medium erodibility class. These data are used by the Government of Ecuador to perform hazard assessments and develop appropriately dimensioned mitigation measures.

2. Blending nature and technology to recharge groundwater supplies. In many regions of the country, agriculture is a water-intensive activity. Pumping groundwater from local aquifers to irrigate crops has increased yields but is steadily reducing the supply of available water for future use. ARS researchers at Oxford, Misssissippi, are tackling that challenge with an innovative approach that marries nature and technology by pumping clean water into the ground through wells. The Groundwater Transfer and Injection Pilot (GTIP) project takes advantage of the fact that riverbanks have a unique combination of geology and microbiology that naturally filters the water that flows through them. By extracting water that has already been cleaned in this way, and then using injection wells to move it into depleted underground aquifers, land managers can recharge the aquifers, maintaining the viability of critical agroecosystems. GTIP is the first to combine the extraction and injection processes in an intensively cultivated agricultural region. In doing so, it will help determine whether the approach could be applied on a wide scale, improving the sustainability of groundwater resources and potentially transforming and protecting large swaths of agricultural land.

3. Estimation of soil erosion using high resolution landscape descriptions. Soil erosion by water continues to be a major threat to the environment and to the sustainability of food production systems. Modeling provides data to guide conservation strategies, evaluate their efficiency, predict how conservation is affected by changes in management or climate. The USDA conservation management planning tool Revised Universal Soil Loss Equation, Version 2 – RUSLE2 – computes erosion over one-dimensional flow paths and is limited as the calculated erosion depends on the selection of representative profiles. ARS researchers at Oxford, Mississippi, developed new methodologies and software to compute erosion with the RUSLE2 model in two dimensions, covering entire fields or farms to provide a more reliable estimation of annual soil loss, with detailed maps showing where erosion and deposition occur. The new modeling approach combines the automated retrieval and processing of high-resolution terrain, soils, and land use data from online databases, with newly developed geoprocessing tools that create landscape descriptions for modeling that consider how topography and runoff accumulation drive the erosion process. By extending the proven RUSLE2 erosion technology and representing actual field conditions, the new approach improves soil erosion estimations, identifies erosion-prone areas, and provides better information for field specific conservation planning. The integration of data and modeling tools will permit an agile transition to end users, including scientists, managers, and other stakeholders involved in soil conservation.

4. Different sources of soil erosion can be more effectively controlled by integrating a variety of conservation practices. Conservation practices have been recognized as an important mitigation tool to reduce soil loss and sediment transport from agricultural fields. Understanding their combined impact on sediment loads when many varied practices are placed throughout the watershed remains a challenge. ARS researchers at Oxford, Mississippi, investigated the impact of conservation practices on erosion from sheet and rill and ephemeral gully sources at field and watershed scales on a USDA Conservation Effects Assessment Project (CEAP) watershed draining into the Chesapeake Bay using USDA watershed simulation technology. Three separate time periods were evaluated representing before, after, and a transition period to describe when conservation practice conditions were implemented to determine their impact on sediment loads. Results showed that applying a mix of natural riparian vegetative buffers, edge-of-field filter strips, and grassed waterway conservation practices reduced sediment yield and loads by approximately 10% for ephemeral gully and 30% for sheet & rill sources compared to single practices alone. The development of conservation plans when considering the watershed as an integrated system to maximize conservation resources, productivity, competitiveness, and long-term sustainability of farm management operations is key. Soil erosion prediction technology that can be customized to quantify varied and integrated sources and sinks of sediment is one tool in the toolbox to support stakeholders in developing comprehensive mitigation plans.

5. RUSLE2 climate update incorporates climate records from 1971-2022. The climate database for USDA-Natural Resources Conservation Service (USDA-NRCS) conservation planning covers 1971-1999. ARS researchers at Oxford, Mississippi, collaborated with Middle Tennessee State University to download all National Oceanic and Atmospheric Administration-National Climate Data Center (NCDC) records for the 1971-2022 period. Climate records were gridded and populated with closest NCDC station, gaps were filled by neighboring stations, events larger than the 50-year planning period were eliminated, and events with less than (<) 13 mm were also eliminated. The current (1971-1999) NRCS climate was reproduced then adjusted to the new 1992-2022 (30-yr) period. The elimination of both large (> 50-yr occurrence) and small (< 13-mm, events with little to no erosion) events are essential to fairness to the farmer. The most recent 30-year records were used to generate the county climate records used for the USDA conservation management planning tool Revised Universal Soil Loss Equation, Version 2 (RUSLE2). Protocols to update the climate records every five years using the most recent 30-year records were documented. Climate updates are essential to conservation management incorporating effects of more recent weather patterns (i.e., wet and dry periods, intensity and duration characteristics, etc.) to balance soil conservation and profitability on all United States farms.

6. Quantifying the effects of three repeated periods of rapidly changing flow rates on sand transport and sand bed topography. Streams and rivers often have flow rates that change with time, which affects the configuration of the channel bed and the transport of sediments. These rapidly changing conditions make it more difficult to predict the amount of sediment transported through the channel, and research is needed to better understand the mechanics of sand beds in unsteady flows in order improve predictive relationships. ARS researchers at Oxford, Mississippi, used a laboratory flume to create three repeated periods of increased flow rate that varied from 1-6 hours and mimicked flows caused by runoff events in streams. Major results include the finding that repeated hydrographs continued to have counter-clockwise hysteresis in the relationship between transport rate and flow rate and that the Engelund-Hansen method, a predictive equation for total sediment load, was still effective at predicting transport rates based on hydraulic parameters for all lengths of repeated hydrographs. These results will help to understand the mechanisms that affect sediment transport and sand-bed morphology in streams with rapidly changing flows, which occur during runoff events and dam-releases. They will be used by researchers in the fields of sediment transport and river engineering, including those focused on modeling flow and sediment transport processes.

7. RUSLE2 new web-application and development partnered with Amazon Web Services. The USDA conservation management planning tool Revised Universal Soil Loss Equation, Version 2 (RUSLE2) is a Microsoft Windows desktop application, and therefore has limited scalability, updatability, installation requirements, and operating system compatibility as compared to web-based applications. To move RUSLE2 to web-application requires RUSLE2 code updates to address Microsoft Foundation Class (MFC) Library updates, providing adaptability into multiple environments (i.e., UNIX, MacOS, or Microsoft Windows) that enable RUSLE2 to improve efficiency and speed as we transition to cloud computing. ARS researchers at Oxford, Mississippi, in collaboration with Clemson University, University of Tennessee, and Middle Tennessee State University have partnered with Amazon Web Services to provide the USDA Natural Resources Conservation Service with the capability to serve all conservation management planners from one location, saving personal attributes locally. This will also enable the group to move into the field with the planners on their tablets or phones, providing service to the farmers on their farms.

8. Established a field site for levee erosion research. Wind-driven waves erode earthen levees, causing significant maintenance costs for irrigation reservoirs and aquaculture ponds. Irrigation reservoirs are a conservation practice for reducing dependence on groundwater for crop irrigation. Surface water is stored in the reservoirs during months with high precipitation and then used for irrigation in the summer, when crops need the most water. A common problem with the reservoirs is rapid levee erosion caused by wind-driven waves. To help solve the problem of wave erosion, ARS researchers at Oxford, Mississippi, established a field study at Johnson Reservoir near Shelby, MS, where the effects of two cost-effective best management practices are assessed: floating wave barriers and geotextile. The findings will help agricultural producers who depend on irrigation reservoirs for storing water by both demonstrating full-scale floating wave barriers and collecting new data on the effectiveness of the system for reducing levee erosion.

Review Publications
Fang, J., Al-Hamdan, M.Z., O'Reilly, A.M., Ozeren, Y., Rigby, J.R., Jia, Y. 2023. A novel floodwave response model for time-varying streambed conductivity using space-time collocation Trefftz method. Journal of Hydrology. 625(A). Article 129996. https://doi.org/10.1016/j.jhydrol.2023.129996.
Wren, D.G., Kuhnle, R.A., Langendoen, E.J., Mcalpin, T.O. 2024. Sediment transport and bed topography for realistic unsteady flow hydrographs of varying length in a laboratory flume. Journal of Hydraulic Engineering. 150(4). Article 13769. https://doi.org/10.1061/JHEND8.HYENG-13769.
Heintzman, L.J., Mcintyre, N.E., Langendoen, E.J., Read, Q.D. 2024. Cultivation and dynamic cropping processes impart land-cover heterogeneity within agroecosystems: a metrics-based case study in the Yazoo-Mississippi Delta (USA). Landscape Ecology. 39. Article 29. https://doi.org/10.1007/s10980-024-01797-0.
Zhang, Y., Al-Hamdan, M., Bingner, R.L., Chao, X., Langendoen, E.J., O'Reilly, A.M., Vieira, D.A. 2024. Application of a 1D model for overland flow simulations on 2D complex domains. Advances in Water Resources. 188. Article 104711. https://doi.org/10.1016/j.advwatres.2024.104711.
Zhang, Y., Al-Hamdan, M., Bingner, R.L., Chao, X., Langendoen, E.J., Vieira, D.A. 2023. Generation of 1D channel networks for overland flow simulations on 2D complex domains. Journal of Hydrology. 628:1-15. https://doi.org/10.1016/j.jhydrol.2023.130560.
Fang, J., Al-Hamdan, M.Z., O'Reilly, A.M., Ozeren, Y., Rigby, J.R. 2024. A three-dimensional numerical model for variably saturated groundwater flow using meshless weak-strong form method. Environmental Modelling & Software. 175:1-22. https://doi.org/10.1016/j.envsoft.2024.105982.
Barrera Crespo, P., Espinoza Giron, P., Bedoya, R., Gibson, S., East, A., Langendoen, E.J., Boyd, P. 2024. Major fluvial erosion and a 500-Mt sediment pulse triggered by lava-dam failure, Rio Coca, Ecuador. Earth Surface Processes and Landforms. 49(3):1058-1080. https://doi.org/10.1002/esp.5751.
Rebillout, L., Ozeren, Y., Langendoen, E.J., Altinakar, M. 2024. Application of material point method and Mohr-Coulomb strain softening constitutive model in simulations of multiphase granular flows. Journal of Hydraulic Engineering. 150(3). Article 04024008. https://doi.org/10.1061/JHEND8.HYENG-13736.
Zhu, J., Wang, Y., Zheng, B., Langendoen, E.J., Wang, Y. 2024. How revegetation reinforces soil at early stage of restoration: A 6-year field study in southwest China. Journal of Plant Nutrition and Soil Science. 187(2):274-286. https://doi.org/10.1002/jpln.202300236.
Locke, M.A., Witthaus, L.M., Lizotte Jr, R.E., Heintzman, L.J., Moore, M.T., O'Reilly, A.M., Wells, R.R., Langendoen, E.J., Bingner, R.L., Gholson, D., Taylor, J.M., Johnson II, F.E. 2024. The LTAR cropland common experiment in the Lower Missisippi River Basin. Journal of Environmental Quality. 53:957-967,https://doi.org/10.1002/jeq2.20577.