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Three-dimensional numerical modeling of nearshore circulation

Acta Oceanologica Sinica 2008年第z1期27卷 101-118页

作者： SUN Detong south florida water management district West Palm Beach FL 33406 U S A

A three-dimensional nearshore circulation model was developed by coupling CH3D, a three-dimensional hydrodynamic model and REF/DIF, a nearshore wave transformation model. The model solves the three-dimensional wave-averaged equations of motion. Wave-induced effects on circulation were introduced in the form of radiation stresses, wave-induced mass transport, wave-induced enhancement of bottom friction and wave-induced turbulent mixing. Effects of breaking waves were considered following Svendsen (1984a and 1984b) and Stive and Wind (1986). The model was successfully tested against the analytical solution of longshore currents by Longuet and Higgins (1970). The model successfully simulated the undertow as observed in a laboratory experiment by Stive and Wind (1982). In addition, the model was applied to a physical model by Mory and Hamm (1997) and successfully reproduced the eddy behind a detached breakwater as well as the longshore current on the open beach and the contiguous eddy in the open area of the wave tank. While the qualitative agreement between model results and experimental observations was very good, the quantitative agreement needs to be further improved. Albeit difficult to explain every discrepancy between the model results and observations, in general, sources of errors are attributed to the lack of understanding and comprehensive description of following processes: (1)the horizontal and vertical distribution of radiation stress, especially for breaking waves;(2)the detailed structure of turbulence;(3)Wave-current interaction (not included at this moment); and (4)the wave-current boundary layer and the resulting bottom shear stress.

关键词： waves wave-induced currents 3D model radiation stress breaking waves surface roller undertow longshore currents nearshore circulation

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Contaminant Removal of Domestic Wastewater by Constructed Wetlands： Effects of Plant Species

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Journal of Integrative Plant Biology 2007年第4期49卷 437-446页

作者： Qiong Yang Zhang-He Chen Jian-Gang Zhao Bin-He Gu College of Life Sciences South China Normal University Guangzhou 510631 China Everglades Division South Florida Water Management District West Palm Beach Florida 33406 USA

A comparative study of the efficiency of contaminant removal between five emergent plant species and between vegetated and unvegetated wetlands was conducted in small-scale （2.0 m×1.0 m×0.7 m, lengthxwidthxdepth） constructed wetlands for domestic wastewater treatment in order to evaluate the decontaminated effects of different wetland plants. There was generally a significant difference in the removal of total nitrogen （TN） and total phosphorus （TP）, but no significant difference in the removal of organic matter between vegetated and unvegetated wetlands. Wetlands planted with Canna indica Linn., Pennisetum purpureum Schum., and Phragmites communis Trin. had generally higher removal rates for TN and TP than wetlands planted with other species. Plant growth and fine root （root diameter ≤ 3 mm） biomass were related to removal efficiency. Fine root biomass rather than the mass of the entire root system played an important role in wastewater treatment. Removal efficiency varied with season and plant growth. Wetlands vegetated by P. purpureum significantly outperformed wetlands with other plants in May and June, whereas wetlands vegetated by P. communis and C. indica demonstrated higher removal efficiency from August to December. These findings suggest that abundance of fine roots is an important factor to consider in selecting for highly effective wetland plants. It also suggested that a plant community consisting of multiple plant species with different seasonal growth patterns and root characteristics may be able to enhance wetland performance.

关键词： constructed wetlands contaminants domestic wastewater plant species removal efficiency total N total P.

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Effects of river width changes on flow characteristics based on flume experiment

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Journal of Mountain Science 2016年第2期13卷 361-368页

作者： WANG Xie-kang WANG Bing-jie LIU Xing-nian Zhang Li-qiong State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Hydrology and Hydraulics Section South Florida Water Management District

The rapid changes in flow pattern due to varying channel widths will make significantly impact on the hydraulic structures and evolutions of open channel. To better understand the impact of varying width, a flume experiment with adjustable width and a depth-averaged two-dimension numerical model were used to analyze the variations of flow parameters. Our experimental results showed that flow velocity gradually increased with decreasing water depth in converging region, and decreased with increasing water depth in diverging zones. It was also found that the turbulence intensity laws in three directions were not agreed with the theoretical relationships proposed by Nezu and Nakagawa in 1993 in straight open channel flows. The flow in the channel with varying width may change from the supercritical flow to the subcritical flow as a function of Froude number. Our numerical simulations with different flow rates showed that most of the hydraulic jumps in diverging region were submerged jump and the degree of submergence increased with increasing flow rate in gradual channel transition. When the flow rate increased, the range of supercritical flow rapidly decreased and the flow changed from the supercritieal condition to the subcritical condition in diverging sections.

关键词： Gradual channel transition Flow pattern Experimental study Numerical simulation

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Phosphorus removal in small constructed wetlands dominated by submersed aquatic vegetation in south florida, USA

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Journal of Plant Ecology 2008年第1期1卷 67-74页

作者： Binhe Gu Everglades Division South Florida Water Management DistrictWest Palm BeachFL 33406USA

Aims Free-surface flow-constructed wetland is a powerful means for the reduction of contaminants from agricultural *** dominated by submerged aquatic vegetations(SAVs)may take up nutrients,particularly phosphorus(P),from surface flow with high *** objective of this study was to assess P removal performance by the SAV community under high and low P *** Weekly or biweekly inflow and outflow water samples were collected from four small constructed wetlands(test cells)planted with SAV in south florida,USA,between September 1999 and September *** test cells were divided into two groups,with the north test cells receiving a higher inflow total phosphorus(TP)concentration(average=75 lg l^(-1))than the south test cells receiving a lower TP concentration(average=23 lg l^(-1)).Limerock(LR)berms were installed in two of these test cells to allow an evaluation of the efficiency of this physical barrier to enhance wetland *** findings North test cells displayed high TP removal of;60%while the removal efficiency of the south test cells was only;20%.Soluble reactive phosphorus concentrations in both north and south test cells were sequestered down to near-detection *** removal efficiencies for particulate phosphorus were also observed in the north test *** LR berms at the two test cells were found to be associated with decreases of an average TP removal of 2 lg l^(-1).Outflow TP concentration did not increase with inflow TP concentration,but increased with nominal hydraulic loading *** from this study demonstrated high P removal from inflow water containing high TP concentration by the SAV wetland and the importance of hydraulic regime to wetland performance.

关键词： phosphorus dominated planted

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Carbon pool trends and dynamics within a subtropical peatland during long-term restoration

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Ecological Processes 2017年第1期6卷 449-462页

作者： Paul Julian II Stefan Gerber Alan L.Wright Binhe Gu Todd Z.Osborne University of florida Soil and Water Sciences DepartmentFt.PierceFL 34945USA. University of florida Soil and Water Sciences DepartmentGainesvilleFL 32611USA. south florida water management district Water Quality BureauWest Palm BeachFL 33406USA. University of florida Whitney Laboratory for Marine BioscienceSt AugustineFL 32080USA.

Introduction:The florida Everglades has undergone significant ecological change spanning the continuum of disturbance to *** the restoration effort is not complete and the ecosystem continues to experience short duration perturbations,a better understanding of long-term C dynamics of the Everglades is needed to facilitate new restoration *** study evaluated temporal trends of different aquatic carbon(C)pools of the northern Everglades Protection Area over a 20-year period to gauge historic C cycling *** inorganic C(DIC),dissolved organic C(DOC),particulate organic C(POC),and surface water carbon dioxide(pCO2(aq))were investigated between May 1,1994 and April 30,***:Annual mean concentrations of DIC,DOC,POC,and pCO2(aq)significantly decreased through time or remained constant across the water Conservation Areas(WCAs).Overall,the magnitude of the different C pools in the water column significantly differed between *** of CO2 was dynamic across the Everglades ranging from 420 to 2001 kg CO2 year−***,the historic trend in CO2 flux from the marsh declined across our study area while pCO2(aq)largely remained somewhat constant with the exception of water Conservation Area 2 which experienced significant declines in pCO2(aq).Particulate OC concentrations were consistent between WCAs,but a significantly decreasing trend in annual POC concentrations was ***:Hydrologic condition and nutrient inputs significantly influenced the balance,speciation,and flux of C pools across WCAs suggesting a subsidy-stress response in C dynamics relative to landscape scale responses in nutrient *** interplay between nutrient inputs and hydrologic condition exert a driving force on the balance between DIC and DOC production via the metabolism of organic matter which forms the base of the aquatic food *** the restoration trajectory as water quality and hydrology continues to improve,it is expect

关键词： Inorganic carbon Organic carbon Carbon dioxide Particulate carbon Hydrology Nutrients

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Evaluation of nutrient stoichiometric relationships among ecosystem compartments of a subtropical treatment wetland. Do we have “Redfield wetlands”?

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Ecological Processes 2019年第1期8卷 267-287页

作者： Paul Julian II Stefan Gerber Rupesh K.Bhomia Jill King Todd Z.Osborne Alan L.Wright Matthew Powers Jacob Dombrowski Soil and water Sciences Department University of FloridaFt.PierceFL34945USA Soil and water Sciences Department University of FloridaGainesvilleFL 32611USA south florida water management district Water Quality Treatment TechnologiesWest Palm BeachFL 33406USA Whitney Laboratory for Marine Bioscience University of FloridaSt AugustineFL 32080USA.

Background:Evaluation of carbon(C),nitrogen(N),and phosphorus(P)ratios in aquatic and terrestrial ecosystems can advance our understanding of biological processes,nutrient cycling,and the fate of organic matter(OM)in these *** of aquatic ecosystems can change the accumulation and decomposition of OM which can alter biogeochemical cycling and alter the base of the aquatic food *** study investigated nutrient stoichiometry within and among wetland ecosystem compartments(i.e.,water column,flocculent,soil,and aboveground vegetation biomass)of two subtropical treatment wetlands with distinct vegetation *** flow-ways(FWs)within the network of Everglades Stormwater Treatment Areas in south florida(USA)were selected for this *** evaluated nutrient stoichiometry of these to understand biogeochemical cycling and controls of nutrient removal in a treatment wetland within an ecological stoichiometry ***:This study demonstrates that C,N,and P stoichiometry can be highly variable among ecosystem compartments and between *** law slopes of C,N,and P within surface water floc,soil,and vegetation were significantly different between and along ***:Assessment of wetland nutrient stoichiometry between and within ecosystem compartments suggests unconstrained stoichiometry related to P that conforms with the notion of P limitation in the *** in N:P ratios between floc and soil suggest different pathways of organic nutrient accumulation and retention between *** nutrient stoichiometry was highly variable and decoupled(or close to decoupled as indicated by<25%explained variation between parameters),in particular with respect to *** hypothesize that decoupling may be the imprint of variability in inflow nutrient ***,despite active biogeochemical cycles that could act to restore nutrient stoichiometry along the FW,there was little evidence that such balancing occurred,as the

关键词： Decomposition Mineralization Everglades Treatment wetlands

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A long term calibration and verification of a submerged aquatic vegetation model for Lake Okeechobee

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Ecological Processes 2013年第1期2卷 232-244页

作者： Kang-Ren Jin Zhen-Gang Ji south florida water management district P.O.Box 24680West Palm BeachFL 334164680USA Department of Civil Engineering Catholic University of AmericaPangborn HallRoom G12WashingtonDC 20064USA

Introduction:Submerged aquatic vegetation(SAV)has multiple functions in Lake *** 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 *** 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 ***: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 ***:Total suspended solids affect light attenuation and are another major driving factor for SAV growth in the nearshore and littoral zone *** model performs reasonably well in reproducing the spatial distribution of ***:The theoretical analysis and model sensitivity tests indicate that SAV growth is primarily controlled by light and *** light available for SAV growth depends on the water depth and the *** 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.

关键词： Submerged aquatic vegetation(SAV) SAV modeling Lake Okeechobee Long term simulation

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A spatially distributed,deterministic approach to modeling Typha domingensis(cattail)in an Everglades wetland

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Ecological Processes 2012年第1期1卷 12-32页

作者： Gareth Lagerwall Gregory Kiker Rafael Muñoz-Carpena Matteo Convertino Andrew James Naiming Wang Frazier Rogers Hall University of FloridaPO Box 110570GainesvilleFL 32611-0570USA Soil and water Engineering Technology Inc.3960 Magnolia Leaf LSuwaneeGA 30024USA Hydrologic and Environmental Systems Modeling South Florida Water Management District3301 Gun Club RdWest Palm BeachFL 33406USA.

Introduction:The emergent wetland species Typha domingensis(cattail)is a native florida Everglades monocotyledonous *** has become invasive due to anthropogenic disturbances and is out-competing other vegetation in the region,especially in areas historically dominated by Cladium jamaicense(sawgrass).There is a need for a quantitative,deterministic model in order to accurately simulate the regional-scale cattail dynamics in the ***:The Regional Simulation Model(RSM),combined with the Transport and Reaction Simulation Engine(TARSE),was adapted to simulate *** provides a framework for user-defineable equations and relationships and enables multiple theories with different levels of complexity to be tested *** models,or levels,of increasing complexity were used to simulate cattail dynamics across water Conservation Area 2A(WCA2A),which is located just south of Lake Okeechobee,in florida,*** levels of complexity were formulated to correspond with five hypotheses regarding the growth and spread of *** first level of complexity assumed a logistic growth pattern to test whether cattail growth is density *** second level of complexity built on the first and included a Habitat Suitability Index(HSI)factor influenced by water depth to test whether this might be an important factor for cattail *** third level of complexity built on the second and included an HSI factor influenced by soil phosphorus concentration to test whether this is a contributing factor for cattail *** fourth level of complexity built on the third and included an HSI factor influenced by(a level 1–simulated)sawgrass density to determine whether sawgrass density impacted the rate of cattail *** fifth level of complexity built on the fourth and included a feedback mechanism whereby the cattail densities influenced the sawgrass densities to determine the impact of inter-species interactions on the cattail dy

关键词： Typha Modeling Ecology Dynamics Model complexity water conservation area 2A Transport and reaction simulation engine Regional simulation model

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TWO COUNTERMEASURE STRATEGIES TO MITIGATE RANDOM DISRUPTIONS IN CAPACITATED SYSTEMS

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Journal of Systems Science and Systems Engineering 2010年第2期19卷 210-226页

作者： Niyazi O.BAKIR Alex SAVACHKIN Andrés Uribe-SANCHEZ Department of Industrial Engineering Bilkent University Department of Industrial and management Systems Engineering University of South Florida

We examine a capacitated system exposed to random stepwise capacity disruptions with exponentially distributed interarrival times and tmiformly distributed magnitudes. We explore two countermeasure policies for a risk-neutral decision maker who seeks to maximize the long-nm average reward. A one-phase policy considers implementation of countermeasures throughout the entirety of a disruption cycle. The results of this analysis form a basis for a two-phase model which implements countermeasures during only a fraction of a disruption cycle. We present an extensive numerical analysis as well as a sensitivity study on the fluctuations of some system parameter values.

关键词： Capacity analysis capacitated system lean random disruptions countermeasure policy

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Kinetic Adsorption of Ammonium Nitrogen by Substrate Materials for Constructed Wetlands

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Pedosphere 2011年第4期21卷 454-463页

作者： ZHU Wen-Ling CUI Li-Hua OUYANG Ying LONG Cui-Fen TANG Xiao-Dan College of Natural Resources and Environmental Science South China Agricultural University Guangzhou 510642 (China) Urban Drainage Monitoring Station of Guangzhou City Guangzhou 510010 (China) Key Laboratory of Agroecology and Rural Environment of Guangdong Regular Higher Education Institutions South China Agricultural University Guangzhou 510642 (China) Department of water Resources St. Johns River Water Management District Palatka Florida 32178 (USA)

Constructed wetlands （CWs） are engineered systems that utilize natural systems including wetland vegetations, soils, and their associated microbial assemblages to assist in treating wastewater. The kinetic adsorption of ammonium nitrogen （NH＋-N） by CW substrate materials such as blast furnace slag （BFS）, zeolite, ceramsite, vermiculite, gravel, paddy soil, red soil, and turf, was investigated using batch experiments and kinetic adsorption isotherms. Both Freundlich and Lang- muir isotherms could adequately predict the NH＋-N adsorption process. The maximum adsorption capacities of NH＋-N, estimated from the Langmuir isotherm, ranked as： zeolite （33 333.33 mg kg^-1）〉 turf （29274.01 mg kg^-1）〉 BFS （5000 mg kg^-1）〉 vermiculite （3333.33 mg kg^-1）〉 gravel （769.23 mg kg^-1）〉 paddy soil （588.24 mg kg^-1）〉 red soil （555.56 mg kg^-1）〉 ceramsite （107.53 mg kg^-1）. Some properties of the substrate materials, including bulk density, specific gravity, hydraulic conductivity, uniformity coefficient （K60）, curvature coefficient （Co）, organic matter, pH, exchangeable （or active） Cu, Fe, Zn and Mn, total Cu, and Fe, Mn, Zn, Cd, Pb and Ca, had negative correlations with NH＋-N adsorption. Other properties of the substrate materials like particle diameter values of D10, 030 and 060 （the diameters of particle sizes of a substrate material at which 10%, 30% and 60%, respectively, of the particles pass through the sieve based on the accumulative frequency）, cation exchange capacity （CEC）, exchangeable （or active） Ca and Mg, and total K and Mg had positive correlations with NH＋-N adsorption. In addition, active K and Na as well as the total Na had significant positive correlations with NH＋-N adsorption. This information would be useful for selection of suitable substrate materials for CWs.

关键词： ammonia removal kinetic adsorption capacity Langmuir isotherm physicochemical properties substrate materials

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