{"id":{"repo_id":"unr","oai_identifier":"oai:scholarwolf.unr.edu:11714/3847"},"canonical_url":"https://search.dev.ndltd.org/etd/unr/oai:scholarwolf.unr.edu:11714/3847","repository":{"repo_id":"unr","name":"University of Nevada - Reno","base_url":"https://scholarwolf.unr.edu/server/oai/request"},"display":{"title":"A Model for Simulating Soil-Zone Processes at the Regional Scale","abstract":"The soil zone has been described as the upper most region of the vadose zone where plant and soil processes enhance storage and permeability, providing a fast pathway for water and solutes to streams. The soil zone connects the land surface to the deeper unsaturated and saturated zones. Modeling of soil-zone processes has been used to gain understanding of watershed hydrologic processes. Currently MODFLOW does not simulate dynamic near-surface hydrologic processes such as, infiltration, hortonian runoff, dunnian runoff, and return flow. The Soil-Zone Flow Package (SZF) for MODFLOW is being developed to address these near-surface components for simulating watershed processes in the context of basin-scale groundwater-flow modeling. especially those processes that partition rainfall into evapotranspiration, runoff, and deep percolation. In a series of test simulations, Richards' equation (RE) was compared with MODFLOW-SZF. Across a range of hydraulic conductivities and applied precipitation rates, MODFLOW-SZF achieved a good infiltration and interflow solution (0.014-0.052 RMSE) with only 6 grid cells and 0.11 seconds computation time compared to the 6250 grid cells and 40 seconds of computation time required for a stable solution to RE. MODFLOW-SZF solutions had negligible errors due to grid effects (<0.01 RMSE) however, RE solutions were sensitive to grid resolution (up to 0.12 RMSE). Errors associated with using the groundwater flow equation to represent soil-zone flow instead of RE were much lower (<0.052 RMSE) than the errors caused by grid effects in RE (0.12 RMSE, 0.5 m cell). This research suggests that the SZF Package will be an effective tool for efficiently representing soil-zone processes at the basin scale.","abstract_html":"The soil zone has been described as the upper most region of the vadose zone where plant and soil processes enhance storage and permeability, providing a fast pathway for water and solutes to streams. The soil zone connects the land surface to the deeper unsaturated and saturated zones. Modeling of soil-zone processes has been used to gain understanding of watershed hydrologic processes. Currently MODFLOW does not simulate dynamic near-surface hydrologic processes such as, infiltration, hortonian runoff, dunnian runoff, and return flow. The Soil-Zone Flow Package (SZF) for MODFLOW is being developed to address these near-surface components for simulating watershed processes in the context of basin-scale groundwater-flow modeling. especially those processes that partition rainfall into evapotranspiration, runoff, and deep percolation. In a series of test simulations, Richards&#x27; equation (RE) was compared with MODFLOW-SZF. Across a range of hydraulic conductivities and applied precipitation rates, MODFLOW-SZF achieved a good infiltration and interflow solution (0.014-0.052 RMSE) with only 6 grid cells and 0.11 seconds computation time compared to the 6250 grid cells and 40 seconds of computation time required for a stable solution to RE. MODFLOW-SZF solutions had negligible errors due to grid effects (&lt;0.01 RMSE) however, RE solutions were sensitive to grid resolution (up to 0.12 RMSE). Errors associated with using the groundwater flow equation to represent soil-zone flow instead of RE were much lower (&lt;0.052 RMSE) than the errors caused by grid effects in RE (0.12 RMSE, 0.5 m cell). This research suggests that the SZF Package will be an effective tool for efficiently representing soil-zone processes at the basin scale.","abstract_has_math":false,"creators":["Henson, Wesley R."],"institution":null,"degree_name":null,"degree_level":"Master's Degree","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Niswonger, Richard G."],"committee_chairs":[],"committee_members":["Prudic, David E.","Pohll, Greg"],"year":2011,"date_issued":"2011","date_published":"2011","updated_at":"2026-07-27T21:47:58Z","subjects":["Infiltration","Interflow","MODFLOW","Recharge","Soil-Zone","Stormflow"],"languages":[],"rights":["In Copyright(All Rights Reserved)"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/11714/3847","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Niswonger, Richard G."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Prudic, David E.","Pohll, Greg"]},{"key":"dc:creator","label":"Author","values":["Henson, Wesley R."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2018-08-29T15:45:04Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2018-08-29T15:45:04Z"]},{"key":"dc:date.issued","label":"Date","values":["2011"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Master's Degree"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Infiltration","Interflow","MODFLOW","Recharge","Soil-Zone","Stormflow"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright(All Rights Reserved)"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/11714/3847"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The soil zone has been described as the upper most region of the vadose zone where plant and soil processes enhance storage and permeability, providing a fast pathway for water and solutes to streams. The soil zone connects the land surface to the deeper unsaturated and saturated zones. Modeling of soil-zone processes has been used to gain understanding of watershed hydrologic processes. Currently MODFLOW does not simulate dynamic near-surface hydrologic processes such as, infiltration, hortonian runoff, dunnian runoff, and return flow. The Soil-Zone Flow Package (SZF) for MODFLOW is being developed to address these near-surface components for simulating watershed processes in the context of basin-scale groundwater-flow modeling. especially those processes that partition rainfall into evapotranspiration, runoff, and deep percolation. In a series of test simulations, Richards' equation (RE) was compared with MODFLOW-SZF. Across a range of hydraulic conductivities and applied precipitation rates, MODFLOW-SZF achieved a good infiltration and interflow solution (0.014-0.052 RMSE) with only 6 grid cells and 0.11 seconds computation time compared to the 6250 grid cells and 40 seconds of computation time required for a stable solution to RE. MODFLOW-SZF solutions had negligible errors due to grid effects (<0.01 RMSE) however, RE solutions were sensitive to grid resolution (up to 0.12 RMSE). Errors associated with using the groundwater flow equation to represent soil-zone flow instead of RE were much lower (<0.052 RMSE) than the errors caused by grid effects in RE (0.12 RMSE, 0.5 m cell). This research suggests that the SZF Package will be an effective tool for efficiently representing soil-zone processes at the basin scale."]},{"key":"dc:format","label":"Dc Format","values":["PDF"]},{"key":"dc:title","label":"Title","values":["A Model for Simulating Soil-Zone Processes at the Regional Scale"]}]}],"canonical_facts":{"dc:contributor.advisor":["Niswonger, Richard G."],"dc:contributor.committeemember":["Prudic, David E.","Pohll, Greg"],"dc:creator":["Henson, Wesley R."],"dc:date.accessioned":["2018-08-29T15:45:04Z"],"dc:date.available":["2018-08-29T15:45:04Z"],"dc:date.issued":["2011"],"dc:description.abstract":["The soil zone has been described as the upper most region of the vadose zone where plant and soil processes enhance storage and permeability, providing a fast pathway for water and solutes to streams. The soil zone connects the land surface to the deeper unsaturated and saturated zones. Modeling of soil-zone processes has been used to gain understanding of watershed hydrologic processes. Currently MODFLOW does not simulate dynamic near-surface hydrologic processes such as, infiltration, hortonian runoff, dunnian runoff, and return flow. The Soil-Zone Flow Package (SZF) for MODFLOW is being developed to address these near-surface components for simulating watershed processes in the context of basin-scale groundwater-flow modeling. especially those processes that partition rainfall into evapotranspiration, runoff, and deep percolation. In a series of test simulations, Richards' equation (RE) was compared with MODFLOW-SZF. Across a range of hydraulic conductivities and applied precipitation rates, MODFLOW-SZF achieved a good infiltration and interflow solution (0.014-0.052 RMSE) with only 6 grid cells and 0.11 seconds computation time compared to the 6250 grid cells and 40 seconds of computation time required for a stable solution to RE. MODFLOW-SZF solutions had negligible errors due to grid effects (<0.01 RMSE) however, RE solutions were sensitive to grid resolution (up to 0.12 RMSE). Errors associated with using the groundwater flow equation to represent soil-zone flow instead of RE were much lower (<0.052 RMSE) than the errors caused by grid effects in RE (0.12 RMSE, 0.5 m cell). This research suggests that the SZF Package will be an effective tool for efficiently representing soil-zone processes at the basin scale."],"dc:format":["PDF"],"dc:identifier.uri":["http://hdl.handle.net/11714/3847"],"dc:rights":["In Copyright(All Rights Reserved)"],"dc:subject":["Infiltration","Interflow","MODFLOW","Recharge","Soil-Zone","Stormflow"],"dc:title":["A Model for Simulating Soil-Zone Processes at the Regional Scale"],"dc:type":["Thesis"],"thesis:degree_level":["Master's Degree"]},"updated_at":"2026-07-27T21:47:58Z"}