Location: Watershed Physical Processes Research
2022 Annual Report
Objectives
1. Develop physically based multidimensional numerical models and technology for watershed erosion and sediment transport processes, water quality issues due to agro-pollution, and surface-groundwater interactions in agriculture landscapes.
1.1. Expand CCHE1D model capabilities.
1.2. Simulate rain-induced watershed soil erosion over tilled and non-tilled agricultural land and sediment transport.
1.3. Develop a coupled surface-subsurface water model.
1.4. Improve CCHE water quality and pollutant transport models.
2. Enhance the Decision Support System for the web-based Agricultural Integrated Management System (AIMS) by integrating watershed and channel network technology with geospatial and remote sensing data for effective watershed runoff, sediment, and water quality management.
2.1. Improve AIMS and AnnAGNPS integration.
2.2. Integrate CCHE1D channel network delineation model and multiple-scaled channel networks and flow model into AIMS.
2.3. Develop assessments of the AIMS integrated technology with case studies.
2.4. Explore cloud computing capability for AIMS.
Approach
In order to better assess and predict the direct impacts of water availability and soil erosion from agricultural fields, gullies and channels, existing technology must be developed and upgraded to assess and improve predictions for more realistic conditions. This includes technology that is needed for decision making in identifying, targeting and implementing conservation practices that protect the landscape. The first objective of the project plan focuses on the development and improvement of numerical models associated with watershed erosion and sediment transport processes, water quality issues due to agro-pollution, and surface-groundwater interactions in agriculture landscapes. This objective relates to the ARS National Program Action 211, Component 1 (Effective Water Management in Agriculture) and Component 2 (Erosion, Sedimentation, and Water Quality Protection). The second objective focuses on the development and improvement of a watershed management tools to assess runoff, sediment, and water quality conservation practice impacts. This objective is related to NP 211 Component 1 and Component 4 (Watershed Management to Improve Agroecosystem Services).
Progress Report
This is a new project which replaced project 6060-13000-028-000D, "Computational Tools and a Decision Support System for Management of Sediment and Water Quality in Agricultural Watersheds. Please refer to 6060-13000-028-000D for additional information.
Subobjectives (1.1.1--1.1.4): The CCHE1D looped channel network model is under development in order to expand the capabilities of CCHE1D model in agricultural irrigation, soil erosion, and urban flooding. The development consists of two parts: development of CCHE1D-GUI (Graphic User Interface) and development of CCHE1D model. In the CCHE1D-GUI, the watershed-merging delineation has been integrated and a digitization tool for looped channel network generation has been developed. In the CCHE1D model, the junction-point water stage prediction and correction (JPWSPC) method has been implemented to solve the looped channel network with both flow confluences and divergences. The new CCHE1D looped channel network model has been validated by benchmark convergent flow, divergent flow, unsteady flow, and urban flooding cases.
The program code of CCHE1D_WQ model has been modified under PGI Fortran system which is consistent with the updated CCHE1D flow model. The linkage between CCHE1D_WQ and AnnAGNPS models has been improved to take outputs produced by AnnAGNPS model. The updated CCHE1D_WQ will be integrated into CCHE1D model for WQ simulation in channel network.
Subobjectives (1.2.1--1.2.3): The CCHE2D soil erosion model has been refined for considering the raindrop-induced splash erosion and shear flow induced soil surface erosion in the sediment transport module. An experimental landscape and a tilled agricultural field were used to validate the refined CCHE2D soil erosion model. The computing efficiency of this model will be enhanced by parallel computing and mesh adaptation techniques.
After having improved the flow module, the sediment transport module of the CCHE2D-Hybird model is now under development. Benchmark degradation and aggradation cases have been tested, and two field cases with long-term unsteady flows and morphological changes are still in the testing phase.
Subobjectives (1.3.1--1.3.2): A 3-D finite element groundwater model, CCHE3D-GW, which can simulate both saturated and unsaturated groundwater flows, have been developed and thoroughly verified and validated with multiple analytical and numerical solutions. After model verification and validation, CCHE3D-GW has been applied to study a pumping test conducted from February 8, 2017 to February 11, 2017 near the Tallahatchie River in Leflore County, Mississippi, USA. Through the calibration of the simulated pump-induced groundwater drawdowns with the measured data, the hydrogeological information in the study site was obtained. With the calibrated parameters, the pump-induced stream depletion was then analyzed based on the simulation results.
Streambed conductivity can vary substantially over short time intervals during flood events, altering groundwater – surface water interactions. A new flood-wave response model has been developed for estimating time-varying streambed conductivity under a partially penetrating river. This novel method only requires measured river stage and groundwater hydraulic heads in the adjacent monitoring wells in addition to the hydrogeological information of the nearby aquifer. This new model has been validated with two synthetic aquifer-stream interaction cases, and then applied to estimate the time-varying streambed conductivity in the Tallahatchie River near Leflore County, Mississippi, USA. With the estimated time-varying streambed conductivity, the simulated groundwater level responses to the fluctuations of the river stage are found to be more accurate.
In the Mississippi River Valley Alluvial Aquifer, declines in groundwater levels caused by agricultural irrigation have been observed and reported for the past several decades. The groundwater transfer and injection pilot (GTIP) was therefore initiated by the U.S. Department of Agriculture (USDA) Agricultural Research Service (ARS). The newly developed model, CCHE3D-GW, has been applied to simulate an experimental groundwater pump and recharge operation conducted by USDA in Shellmound, Mississippi, USA. The simulation results demonstrate that CCHE3D-GW can capture the general trend of the groundwater responses in both the pumping and recharging parts.
Subobjectives (1.4.1--1.4.2): A new water quality module is being developed to simulate the particulate and dissolved nutrients for the CCHE_WQ model. The phosphate (PO4), organic phosphorus (OP), and organic nitrogen (ON) are each partitioned into particulate and dissolved forms that are simulated separately. This subtask will be completed in March 2023.
The CCHE_WQ model and AnnAGNPS watershed model have been linked to study the response of lake water quality to the upland agricultural practices. AnnAGNPS model was applied to simulate the runoff, sediment, and nutrients from the upland watershed under the alternative agricultural practices, such as reduced-tillage, no-tillage, etc. The outputs of AnnAGNPS were set as boundary conditions for CCHE_WQ to simulate the water quality of the inland lake. This technical approach has been tested using Beasley Lake watershed.
Subobjectives (2.1.1--2.2.1): Agricultural Integrated Management System (AIMS) is a web-based portal for running watershed and channel models with automated input data preparation. AIMS serves as an environment for evaluating the impact of agricultural and channel conservation management practices for any HUC12 level watershed in the United States. AIMS also provides a seamless map server for downloading geospatial data layers. The AIMS system is currently being moved to a new environment which is developed under the Django framework. The state-of-the art Django framework allows using Python based modules/apps for geospatial data layers and databases. The previous version of AIMS used Python 2 heavily relied on console operations and scheduler. Python 2 is not supported after January 2020. The new framework eliminates system level console operations and scheduler which are vulnerable to system failures. The backed scripts in the old system are either discarded or converted to Pyhon 3.1 and migrated to the new system. The new framework is stationed in the testbed machine (menderes.nccche.olemiss.edu) which is updated to the latest version OS and software (Debian 11, PostgreSQL 14 and Python 3.1). Currently the new version of the AIMS portal allows users to create accounts, create projects and scenarios under projects, as well as visualize various geospatial data layers. The development team is currently working on creating a TOPAGNPS geospatial layer that can be accessed using the AIMS web portal. Integrations of the CCHE1D Model and other geospatial data layers including NHDplus and NASA remotely sensed data into AIMS are also ongoing.
Accomplishments
1. A digitization tool for loop channel network. Compared to the dendritic channel network that has only one outlet and junctions with only confluence flow, the looped channel network enables multiple outlets and junctions of both confluence flow and divergent flow. In addition to the source-to-junction and junction-to-end links in the dendritic channel network, ARS researchers in Oxford, Mississippi, developed a new type of link, namely, the junction-to-junction link, has been designed in the looped channel network, based on which the digitization tool is developed. This tool enables digitization of looped channel network from scratch for the CCHE1D looped channel network model.
2. A generator of channel network. In order to enable the CCHE1D model for overland flow simulations on 2D complex domains, ARS researchers in Oxford, Mississippi, developed an automatic generation algorithm, where the channel network generation follows the geometric principle that covers the whole domain without overlapping, and the hydrologic principle that channel network follows the steepest slope. Combining with the watershed-merging delineation tool, this automatic generator enables fast generation of channel networks with cross sections from digital elevation model (DEM) or any structured topography database.
3. A looped channel network model. The CCHE1D looped channel network for flow has been developed by ARS researchers in Oxford, Mississippi. The digitization tool and the generator of channel network enable the CCHE1D model to handle more complicated flow conditions in looped channel networks with multiple outlets and junctions of both flow confluences and divergences,
4. A 3D groundwater model assisted the groundwater transfer and injection project. The Mississippi Alluvial Plain is one of the most productive agricultural areas in the United States, and its crop productions heavily rely on extractions of groundwater from the Mississippi River Valley Alluvial Aquifer. However, declines in regional groundwater levels caused by agricultural irrigation have been observed and reported for the past several decades. The groundwater transfer and injection pilot (GTIP) project was therefore initiated by the U.S. Department of Agriculture (USDA) to mitigate this problem. A 3-D finite element groundwater model, CCHE3D-GW, has been developed and is capable of handling both saturated and unsaturated groundwater flows, unlike other widely used groundwater models such as MODFLOW. CCHE3D-GW has been verified and validated, with multiple analytical and numerical solutions. ARS researchers in Oxford, Mississippi, have successfully applied this to simulate the pump-induced stream depletion for the Tallahatchie River near Leflore County, Mississippi, USA. The application of CCHE3D-GW to various combinations of groundwater extraction and recharge scenarios is underway, which will provide key information to the GTIP project of USDA-ARS in the Lower Mississippi River Basin.
5. A novel method to estimate time-varying streambed conductivity for a partially penetrating river. Streambed conductivity has been reported to change rapidly and strongly during flood events, which can substantially alter groundwater-surface water interactions. However, traditional surface-subsurface water numerical models did not consider this temporal variation. To incorporate the time-varying streambed conductivity into CCHE3D-GW, ARS researchers in Oxford, Mississippi, developed a new flood-wave response model. The scenario that a river partially penetrates an aquifer is considered because it is prevalent in the Lower Mississippi River Basin. This new estimation model has been validated with two representative aquifer-stream interaction cases. The model was then successfully applied to estimate the time-varying streambed conductivity in the Tallahatchie River near Leflore County, Mississippi, USA. With the estimated time-varying streambed conductivity, groundwater – surface water exchanges can be more precisely simulated by the numerical model. Therefore, the predictions for the hydrological processes in the aquifer-stream system can be improved, which is crucial for the GTIP project in the Lower Mississippi River Basin.
6. The current Agricultural Integrated Management System (AIMS) system and its components were upgraded to a new framework. ARS researchers in Oxford, Mississippi, implemented changes to this new technology, so far, the following subtasks have been completed: Updated the AIMS framework: AIMS is migrated to Python based Django framework. Updated user management: The new framework provides better and more secure user authentication management. Updated simulation management: A unique project ID is used to identify and store each simulation. Simulation data is stored in a folder and linked with .josn files. Updated databases: Existing databases are updated. The new system uses single PostgreSQL database. Tracking and logging: A higher level logging module is to be used in the current system, which can be used for each user. This was not possible in the previous version. Error handling: It is easier to track the errors and respond to them since the new framework operation are process level, which does not interfere with the system when the process gives an exception. Admin panel: An admin panel gives control to authorized administrators without having to access the backend. Improved speed: Early tests showed promising results. Also, since no scheduler is used, the live runs of the model are also much faster than the previous version. Mobile ready and cloud ready: The new AIMS system is designed and developed as mobile and cloud ready. A simplified version is already tested on the cloud. TOPAGNPS pre-runs: TOPAGNPS runs are currently executed for a pilot HUC4 watershed. The output will be available as a geospatial layer to the users. TOPAGNPS – CCHE1D integration: Backend modules that links TOPAGNPS network output to CCHE1D geometry are prepared.
