Introduction:Submerged aquatic vegetation(SAV)has multiple functions in Lake Okeechobee.It provides critical habitat for fish and wildlife,stabilizes sediments,reduces phosphorus(P)concentration in the water column by...Introduction:Submerged aquatic vegetation(SAV)has multiple functions in Lake Okeechobee.It provides critical habitat for fish and wildlife,stabilizes sediments,reduces phosphorus(P)concentration in the water column by preventing re-suspension of P-rich sediments,and provides a substrate for attached algae,which also helps to remove P from the water column.Ten year water quality and SAV growth simulations are presented and compared with observed SAV and water quality data collected in the nearshore zone in Lake Okeechobee.Methods:The SAV theory and approach used in the LOEM are modified from the Chesapeake Bay model and incorporate three state variables:shoots(above the bed sediment),roots(in the bed sediment),and epiphytes(attached to the shoots).The SAV model has direct linkages with the water quality model,including(1)a link between the growth and decay of SAV and the nutrient pool of the water quality model;(2)a link between the photosynthesis and respiration of SAV and dissolved oxygen dynamics,and(3)the ways in which settling of particulate organic matter and nutrient uptake affect nutrient levels in the water column and in the sediment bed.Results:Total suspended solids affect light attenuation and are another major driving factor for SAV growth in the nearshore and littoral zone area.The model performs reasonably well in reproducing the spatial distribution of SAV.Conclusions:The theoretical analysis and model sensitivity tests indicate that SAV growth is primarily controlled by light and nutrients.The light available for SAV growth depends on the water depth and the turbidity.In this full scale simulation,the water depth comes from the LOEM hydrodynamic model,and the turbidity depends on the suspended sediment concentration and algal concentration.展开更多
Introduction: The calibration, verification, and validation of calcium (Ca), chloride (Cl), and sulfate (SO_(4)) module ofthe Lake Okeechobee Environment Model (LOEM) was completed. The integrated model could simulate...Introduction: The calibration, verification, and validation of calcium (Ca), chloride (Cl), and sulfate (SO_(4)) module ofthe Lake Okeechobee Environment Model (LOEM) was completed. The integrated model could simulate Ca, Cl, andSO_(4) concentrations and transport due to wind driven currents and waves from 1 Oct 1999 to 30 Sept 2009 in LakeOkeechobee. The enhanced model was also used to estimate lake water quality effects resulting from differentmanagement scenarios that include discharges from planned aquifer storage and recovery (ASR) facilities.Methods: The fate and transport processes of Ca, Cl, and SO_(4) are controlled by their reactivity and their hydrodynamictransport. Reactivity includes chemical, biological, and bio-uptake processes (IJRSA 33:2233-2260, 2012). Hydrodynamictransport includes advection of water current, diffusion, and turbulent mixing within the water column. The depositionand resuspension on the water-sediment bed interface is also included. The mathematical equations for describing Ca,Cl, and SO_(4) substances, including heavy metal and total organic carbon (TOC), are similar.Results: Both the statistical results and the time series comparisons indicate that the simulation of Ca, Cl, and SO_(4) aregenerally simulated well by the LOEM. The root mean square error over the variance rage is Cl <18%, Ca <35%, andSO_(4) < 19%.Conclusions: Cl, Ca, and SO_(4) concentrations in the lake were largely controlled by water temperature and lakeevaporation. Inflows to the lake can also have localized effects on chloride variations. Shallow water depth and highevaporation contribute to high Cl/Ca/ SO_(4) concentration in the lake.展开更多
基金thank the Okeechobee Data Collection Team for SAV data collection.The authors also wish to thank Amy Peters for preparing Figures 2 and 3.
文摘Introduction:Submerged aquatic vegetation(SAV)has multiple functions in Lake Okeechobee.It provides critical habitat for fish and wildlife,stabilizes sediments,reduces phosphorus(P)concentration in the water column by preventing re-suspension of P-rich sediments,and provides a substrate for attached algae,which also helps to remove P from the water column.Ten year water quality and SAV growth simulations are presented and compared with observed SAV and water quality data collected in the nearshore zone in Lake Okeechobee.Methods:The SAV theory and approach used in the LOEM are modified from the Chesapeake Bay model and incorporate three state variables:shoots(above the bed sediment),roots(in the bed sediment),and epiphytes(attached to the shoots).The SAV model has direct linkages with the water quality model,including(1)a link between the growth and decay of SAV and the nutrient pool of the water quality model;(2)a link between the photosynthesis and respiration of SAV and dissolved oxygen dynamics,and(3)the ways in which settling of particulate organic matter and nutrient uptake affect nutrient levels in the water column and in the sediment bed.Results:Total suspended solids affect light attenuation and are another major driving factor for SAV growth in the nearshore and littoral zone area.The model performs reasonably well in reproducing the spatial distribution of SAV.Conclusions:The theoretical analysis and model sensitivity tests indicate that SAV growth is primarily controlled by light and nutrients.The light available for SAV growth depends on the water depth and the turbidity.In this full scale simulation,the water depth comes from the LOEM hydrodynamic model,and the turbidity depends on the suspended sediment concentration and algal concentration.
文摘Introduction: The calibration, verification, and validation of calcium (Ca), chloride (Cl), and sulfate (SO_(4)) module ofthe Lake Okeechobee Environment Model (LOEM) was completed. The integrated model could simulate Ca, Cl, andSO_(4) concentrations and transport due to wind driven currents and waves from 1 Oct 1999 to 30 Sept 2009 in LakeOkeechobee. The enhanced model was also used to estimate lake water quality effects resulting from differentmanagement scenarios that include discharges from planned aquifer storage and recovery (ASR) facilities.Methods: The fate and transport processes of Ca, Cl, and SO_(4) are controlled by their reactivity and their hydrodynamictransport. Reactivity includes chemical, biological, and bio-uptake processes (IJRSA 33:2233-2260, 2012). Hydrodynamictransport includes advection of water current, diffusion, and turbulent mixing within the water column. The depositionand resuspension on the water-sediment bed interface is also included. The mathematical equations for describing Ca,Cl, and SO_(4) substances, including heavy metal and total organic carbon (TOC), are similar.Results: Both the statistical results and the time series comparisons indicate that the simulation of Ca, Cl, and SO_(4) aregenerally simulated well by the LOEM. The root mean square error over the variance rage is Cl <18%, Ca <35%, andSO_(4) < 19%.Conclusions: Cl, Ca, and SO_(4) concentrations in the lake were largely controlled by water temperature and lakeevaporation. Inflows to the lake can also have localized effects on chloride variations. Shallow water depth and highevaporation contribute to high Cl/Ca/ SO_(4) concentration in the lake.
