{"id":{"repo_id":"lsu-thes","oai_identifier":"oai:repository.lsu.edu:gradschool_dissertations-1015"},"canonical_url":"https://search.dev.ndltd.org/etd/lsu-thes/oai:repository.lsu.edu:gradschool_dissertations-1015","repository":{"repo_id":"lsu-thes","name":"Lousiana State University","base_url":"https://repository.lsu.edu/do/oai/"},"display":{"title":"Modeling temporal and spatial variations in dissolved oxygen in Amite River","abstract":"A watershed-based modeling framework is developed in this dissertation for simulating temporal and spatial variations in DO in lowland rivers with organic-rich fine-grained sediment. The modeling framework is based on three major contributions/new models, including (1)VART-DO model for improved estimation of reaeration coefficient (K2) in natural streams, (2)VART-DOS model for simulation of temporal variations in DO in response to sediment resuspension, and (3)VART DO-3L model for simulation of spatial variations in DO. A major advantage of VART-DO model is the capability of simulating DO exchange across the water-sediment interface through the hyporheic exchange mechanism in addition to the air-water exchange. Simulation results from VART-DO model revealed that hyporheic exchange can reduce K2 by 30% while longitudinal dispersion increases K2 by 50%. VART-DOS model is developed for simulation of temporal variations in DO particularly due to sediment resuspension effect during high flow. Application results of VART-DOS model to the Amite River in Louisiana showed that 83% of DO consumption in water column in July 1990 was because of sediment resuspension. A novel feature of VART DO-3L model is that a fine-grained stream with the flocculent layer can be vertically modeled with three layers: overlying water column, an advection-dominated storage zone, and a diffusion-dominated storage zone in relatively consolidated stream bed-sediment. While the importance of flocculent layer to instream DO has been widely reported, VART-DO-3L model is the first modeling tool that incorporates the flocculent layer into DO modeling. This is a unique feature of VART-DO-3L model, making it possible for determining both longitudinal and vertical profiles of DO in streams. Results of VART-DO-3L for the Amite River indicated that the DO level decreases longitudinally from 7.9mg/L at the Denham Springs station to 2.89mg/L at the Port Vincent station. Vertically, DO level drops rapidly from overlying water column to the advection-dominated storage zone and further to the diffusive layer. The DO level in the advective layer is about 40% of that in water column. The thickness of the diffusive layer varies between 0-10mm, depending on effective diffusion coefficient. Developed models in this dissertation are also applicable to sandy/gravel rivers.","abstract_html":"A watershed-based modeling framework is developed in this dissertation for simulating temporal and spatial variations in DO in lowland rivers with organic-rich fine-grained sediment. The modeling framework is based on three major contributions/new models, including (1)VART-DO model for improved estimation of reaeration coefficient (K2) in natural streams, (2)VART-DOS model for simulation of temporal variations in DO in response to sediment resuspension, and (3)VART DO-3L model for simulation of spatial variations in DO. A major advantage of VART-DO model is the capability of simulating DO exchange across the water-sediment interface through the hyporheic exchange mechanism in addition to the air-water exchange. Simulation results from VART-DO model revealed that hyporheic exchange can reduce K2 by 30% while longitudinal dispersion increases K2 by 50%. VART-DOS model is developed for simulation of temporal variations in DO particularly due to sediment resuspension effect during high flow. Application results of VART-DOS model to the Amite River in Louisiana showed that 83% of DO consumption in water column in July 1990 was because of sediment resuspension. A novel feature of VART DO-3L model is that a fine-grained stream with the flocculent layer can be vertically modeled with three layers: overlying water column, an advection-dominated storage zone, and a diffusion-dominated storage zone in relatively consolidated stream bed-sediment. While the importance of flocculent layer to instream DO has been widely reported, VART-DO-3L model is the first modeling tool that incorporates the flocculent layer into DO modeling. This is a unique feature of VART-DO-3L model, making it possible for determining both longitudinal and vertical profiles of DO in streams. Results of VART-DO-3L for the Amite River indicated that the DO level decreases longitudinally from 7.9mg/L at the Denham Springs station to 2.89mg/L at the Port Vincent station. Vertically, DO level drops rapidly from overlying water column to the advection-dominated storage zone and further to the diffusive layer. The DO level in the advective layer is about 40% of that in water column. The thickness of the diffusive layer varies between 0-10mm, depending on effective diffusion coefficient. Developed models in this dissertation are also applicable to sandy/gravel rivers.","abstract_has_math":false,"creators":["Zahraeifard, Vahid"],"institution":"Civil and Environmental Engineering","degree_name":"Doctor of Philosophy (PhD)","degree_level":"Dissertation","degree_discipline":"Civil and Environmental Engineering","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2013,"date_issued":"2013-01-01T08:00:00Z","date_published":"2013-01-01T08:00:00Z","updated_at":"2026-07-24T02:57:00Z","subjects":["Fine-grained sediment","Hyporheic Exchange","Dissolved Oxygen","Organic-rich sediment","Sediment Resuspension","Spatial Variation","Temporal Variation","Uncertainty"],"languages":[],"rights":["unrestricted","Release the entire work immediately for access worldwide."],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["etd-06032013-140227","https://repository.lsu.edu/gradschool_dissertations/16"],"render_values":[{"text":"etd-06032013-140227","href":null,"code":true},{"text":"https://repository.lsu.edu/gradschool_dissertations/16","href":"https://repository.lsu.edu/gradschool_dissertations/16","code":true}]}]},"links":{"outbound_url":"https://doi.org/10.31390/gradschool_dissertations.16","outbound_label":"DOI","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Zahraeifard, Vahid"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2013-05-06"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2022-05-12T23:07:24Z"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Civil and Environmental Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Doctor of Philosophy (PhD)"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Civil and Environmental Engineering"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Fine-grained sediment","Hyporheic Exchange","Dissolved Oxygen","Organic-rich sediment","Sediment Resuspension","Spatial Variation","Temporal Variation","Uncertainty"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["unrestricted","Release the entire work immediately for access worldwide."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["etd-06032013-140227","10.31390/gradschool_dissertations.16","https://repository.lsu.edu/gradschool_dissertations/16"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["A watershed-based modeling framework is developed in this dissertation for simulating temporal and spatial variations in DO in lowland rivers with organic-rich fine-grained sediment. The modeling framework is based on three major contributions/new models, including (1)VART-DO model for improved estimation of reaeration coefficient (K2) in natural streams, (2)VART-DOS model for simulation of temporal variations in DO in response to sediment resuspension, and (3)VART DO-3L model for simulation of spatial variations in DO. A major advantage of VART-DO model is the capability of simulating DO exchange across the water-sediment interface through the hyporheic exchange mechanism in addition to the air-water exchange. Simulation results from VART-DO model revealed that hyporheic exchange can reduce K2 by 30% while longitudinal dispersion increases K2 by 50%. VART-DOS model is developed for simulation of temporal variations in DO particularly due to sediment resuspension effect during high flow. Application results of VART-DOS model to the Amite River in Louisiana showed that 83% of DO consumption in water column in July 1990 was because of sediment resuspension. A novel feature of VART DO-3L model is that a fine-grained stream with the flocculent layer can be vertically modeled with three layers: overlying water column, an advection-dominated storage zone, and a diffusion-dominated storage zone in relatively consolidated stream bed-sediment. While the importance of flocculent layer to instream DO has been widely reported, VART-DO-3L model is the first modeling tool that incorporates the flocculent layer into DO modeling. This is a unique feature of VART-DO-3L model, making it possible for determining both longitudinal and vertical profiles of DO in streams. Results of VART-DO-3L for the Amite River indicated that the DO level decreases longitudinally from 7.9mg/L at the Denham Springs station to 2.89mg/L at the Port Vincent station. Vertically, DO level drops rapidly from overlying water column to the advection-dominated storage zone and further to the diffusive layer. The DO level in the advective layer is about 40% of that in water column. The thickness of the diffusive layer varies between 0-10mm, depending on effective diffusion coefficient. Developed models in this dissertation are also applicable to sandy/gravel rivers."]},{"key":"dc:title","label":"Title","values":["Modeling temporal and spatial variations in dissolved oxygen in Amite River"]}]}],"canonical_facts":{"dc:creator":["Zahraeifard, Vahid"],"dc:date":["2013-05-06"],"dc:date.available":["2022-05-12T23:07:24Z"],"dc:description.abstract":["A watershed-based modeling framework is developed in this dissertation for simulating temporal and spatial variations in DO in lowland rivers with organic-rich fine-grained sediment. The modeling framework is based on three major contributions/new models, including (1)VART-DO model for improved estimation of reaeration coefficient (K2) in natural streams, (2)VART-DOS model for simulation of temporal variations in DO in response to sediment resuspension, and (3)VART DO-3L model for simulation of spatial variations in DO. A major advantage of VART-DO model is the capability of simulating DO exchange across the water-sediment interface through the hyporheic exchange mechanism in addition to the air-water exchange. Simulation results from VART-DO model revealed that hyporheic exchange can reduce K2 by 30% while longitudinal dispersion increases K2 by 50%. VART-DOS model is developed for simulation of temporal variations in DO particularly due to sediment resuspension effect during high flow. Application results of VART-DOS model to the Amite River in Louisiana showed that 83% of DO consumption in water column in July 1990 was because of sediment resuspension. A novel feature of VART DO-3L model is that a fine-grained stream with the flocculent layer can be vertically modeled with three layers: overlying water column, an advection-dominated storage zone, and a diffusion-dominated storage zone in relatively consolidated stream bed-sediment. While the importance of flocculent layer to instream DO has been widely reported, VART-DO-3L model is the first modeling tool that incorporates the flocculent layer into DO modeling. This is a unique feature of VART-DO-3L model, making it possible for determining both longitudinal and vertical profiles of DO in streams. Results of VART-DO-3L for the Amite River indicated that the DO level decreases longitudinally from 7.9mg/L at the Denham Springs station to 2.89mg/L at the Port Vincent station. Vertically, DO level drops rapidly from overlying water column to the advection-dominated storage zone and further to the diffusive layer. The DO level in the advective layer is about 40% of that in water column. The thickness of the diffusive layer varies between 0-10mm, depending on effective diffusion coefficient. Developed models in this dissertation are also applicable to sandy/gravel rivers."],"dc:identifier":["etd-06032013-140227","10.31390/gradschool_dissertations.16","https://repository.lsu.edu/gradschool_dissertations/16"],"dc:rights":["unrestricted","Release the entire work immediately for access worldwide."],"dc:subject":["Fine-grained sediment","Hyporheic Exchange","Dissolved Oxygen","Organic-rich sediment","Sediment Resuspension","Spatial Variation","Temporal Variation","Uncertainty"],"dc:title":["Modeling temporal and spatial variations in dissolved oxygen in Amite River"],"thesis:degree_discipline":["Civil and Environmental Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Doctor of Philosophy (PhD)"],"thesis:institution_name":["Civil and Environmental Engineering"]},"updated_at":"2026-07-24T02:57:00Z"}