modelling of pollution dispersion in natural stream during dry period

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Modelling of pollution dispersion in natural stream during dry period. Yvetta Velskov Institute of Hydrology SAS, Racianska 75, 831 02 Bratislava, Slovakia e-mail: veliskova@uh.savba.sk . Drought consequences environmental economic social. reduction of water quality. - PowerPoint PPT Presentation

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  • Modelling of pollution dispersion in natural stream during dry period

    Yvetta Velskov

    Institute of Hydrology SAS, Racianska 75, 831 02 Bratislava, Slovakia

    e-mail: veliskova@uh.savba.sk

  • Environmental problemsWater pollutiondetermination of transport, dispersion and self-purifying characteristics of channels, optimum location of outlet structures in streams, delineation of mixing zones, prediction of spreading of accidental contaminant waves, etc.determination of pollutant distribution in natural streams in which the bed stream roughness, as results of flow conditions during low flows, forcefully impacts on a flow structure Mathematical and numerical modelling

  • Dead zone model - schemethe mass transfer across the main flow and dead zone interface is proportionalto the concentration difference across them and to the discharge velocity

  • The influence of dead zones was formed to the equations, which represent the conception: transported mass pollutant from the main flow (with the concentration C) gets into a side or a bottom dead zones as into a mixing tank; after that pollutant is mixed within the tank volume and then is exported back to the main flow zone with concentration CDZ .

    The residence time of the fluid in the tank depends onthe mass exchange coefficient between the dead zones and the main flow and also on ratio of interfacial area to the dead zone volume.

  • numerical modelscondition for applicationrange of input datarate of precisionetc.two-dimensional model

  • Hydrodynamic approachc - mass concentration of pollutant [kg.m-3], h - depth [m], t - time [s], x,y,z - longitudinal, transverse and vertical coordinates [m], u,v,w - depth-averaged longitudinal, transverse and vertical velocities [m.s-1], x, y, z - longitudinal, transverse and vertical dispersion coefficients [m2.s-1] Input data: geomorphological characteristics of river, data connected with discharge and water level regime dispersion characteristics at simulated part of river data about pollution sources + influence of dead zones

  • Model MODI: 2-D simulation model for determination of pollutant transport in natural (non-prismatic) channels based on the solution of advection-diffusion equation simulates under conditions of steady flow in non-prismatic channels possibility of simulation:arbitrarily situated unsteady sources of pollutioninfluence of dead zonesself-purification effectInput data:geometric characteristics of cross-sections and velocity profiles in selected location of computed part of streamquantity and location of pollutant sourcescoefficients of transverse dispersionself-purification coefficientdiffusion coefficient with dead zones and the interfacial area between the main flow and dead zones (the volume of dead zones)

  • the mass exchange coefficient between the dead zones and the main flow (from 0.003 m2s-1 to 0.03 m2s-1),the interfacial area of dead zones (from 10% to 30% of active part) and their volume (from 20% to 50% of active part)

  • dz eps Amz Vmz T

    Graf1

    00000.260770.171720.117060.193950.16770.10580.084840.06887

    0.0207267830.173351280.0659488560.0207267830.907420.518960.35050.238130.51950.31870.25270.2136

    0.325975770.457873490.348586810.109286681.39580.892380.586010.330.82060.52830.41390.3513

    1.76554511.78815611.04576040.676446841.82281.20540.85050.561821.2030.76350.60620.4985

    3.35773894.64468372.9865412.00672952.28091.42991.08960.745291.5940.99910.79220.6632

    6.0842536.3668915.43041723.88156122.65811.52681.22140.913492.0221.2590.9630.8148

    6.84737555.66971745.95423965.60376853.22111.78771.33841.07032.3911.461.1380.9772

    4.38277253.291795.7563935.56043073.68122.06281.55561.1572.7451.6831.3321.129

    1.80888291.5488564.51467035.21184394.12332.28731.68311.33192.5661.9051.4951.273

    0.218573350.348586812.26675643.31440114.53322.5631.83961.53582.4041.6711.3011.116

    0.0207267830.15262450.697173621.5262454.87822.82151.98591.38322.2221.4311.1060.9674

    000.239300130.478600274.44833.09142.22871.28042.0261.1920.94330.8197

    0.109286680.0866756393.99433.26582.07441.23511.7790.97940.77820.6616

    0.0207267830.0207267833.80233.06311.92381.11421.6110.73870.59860.4967

    003.31152.81251.78430.90771.4020.49380.42860.3323

    2.91582.5221.59350.778271.1970.250.2660.1825

    2.42692.20891.39260.653480.92610.1042

    2.04542.14571.23040.605370.751

    1.58931.82461.150.492460.3936

    1.41491.51020.953990.3911

    1.0131.21250.770.30286

    0.671820.992910.60390.11823

    0.406010.746760.48711

    0.337650.3611

    T1=1000s

    T2=2000s

    T3=3000s

    T4=4000s

    dzl1020T1

    dzl1020T2

    dzl1020T3

    dzl1020T4

    dzh1020T1

    dzh1020T2

    dzh1020T3

    dzh1020T4

    distance [m]

    concentration [mg/l]

    mz0-digit

    X [m]c [mg/l]T=1000s

    794.5410.000

    853.1480.021

    900.8710.326

    920.9651.766

    949.4313.358

    997.9916.084

    1046.5516.847

    1095.1114.383

    1143.6711.809

    1201.4400.219

    1250.0000.021

    1298.5600.000

    1976.7250.000T=2000s

    2035.3320.173

    2063.7980.458

    2103.1481.788

    2150.8714.645

    2199.4316.367

    2247.9915.670

    2306.5983.292

    2345.1111.549

    2374.4140.349

    2402.8800.153

    2461.4870.000

    3071.8350.000T=3000s

    3168.9550.066

    3217.5150.349

    3256.0281.046

    3294.5412.987

    3353.1485.430

    3372.4055.954

    3430.1745.756

    3449.4314.515

    3508.0382.267

    3546.5510.697

    3575.8540.239

    3605.1570.109

    3643.6710.021

    3672.9740.000

    4254.0190.000T=4000s

    4311.7880.021

    4351.1390.109

    4399.6990.676

    4447.4212.007

    4495.9813.882

    4544.5415.604

    4593.1015.560

    4603.1485.212

    4660.9183.314

    4699.4311.526

    4758.0380.479

    4796.5510.087

    4845.1110.021

    4912.9270.000

    mz0-digit

    T1=1000s

    T2=2000s

    T3=3000s

    T4=4000s

    vzdialenos [m]

    koncentrcia [mg/l]

    mz1020m_v

    xcT=1000sxcT=2000sxcT=1000sxcT=2000s

    750.000.2608Amz=0,113500.171725300.1677Amz=0,113500.1058

    900.000.9074Vmz=0,219600.518966300.5195Vmz=0,214800.3187

    920.001.3958DIFmz=0,00320700.892386800.8206DIFmz=0,0315500.5283

    930.001.822820901.20547201.20316100.7635

    940.002.280921001.42997601.59416600.9991

    950.002.658121101.52688002.02217101.259

    970.003.221121201.78778302.39117501.46

    980.003.681221302.06288702.74517901.683

    990.004.123321402.28739902.56618501.905

    1000.004.533221502.56310002.40420201.671

    1010.004.878221602.821510102.22220601.431

    1070.004.448321803.091410202.02620901.192

    1080.003.994321903.265810401.77921200.9794

    1090.003.802322503.063110501.61121500.7387

    1100.003.311522602.812510601.40221900.4938

    1110.002.915822702.52210701.19722400.25

    1120.002.426922802.208910900.9261

    1130.002.045422902.145711000.751

    1140.001.589323001.824611300.3936

    1150.001.414923101.5102

    1160.001.01323201.2125xcT=3000sxcT=4000s

    1170.000.6718223300.9929122100.0848430900.06887

    1180.000.4060123400.7467623700.252732700.2136

    23700.3376524500.413933600.3513

    25200.606234400.4985

    xcT=3000sxcT=4000s25800.792235100.6632

    1970.000.1170625700.1939526300.96335700.8148

    2690.000.350533700.2381326801.13836300.9772

    3110.000.5860138300.3327401.33236901.129

    3240.000.850542200.5618228001.49537601.273

    3270.001.089644100.7452930401.30140501.116

    3280.001.221444500.9134930901.10641000.9674

    3290.001.338444701.070331200.943341400.8197

    3310.001.555644801.15731600.778241900.6616

    3320.001.683145101.331932000.598642400.4967

    3330.001.839645401.535832400.428643000.3323

    3340.001.985946101.383232900.26643700.1825

    3370.002.228746201.280433700.1042

    3430.002.074446301.2351

    3440.001.923846401.1142

    3450.001.784346600.9077

    3460.001.593546700.77827

    3470.001.392646800.65348

    3480.001.230446900.60537

    3490.001.1547000.49246

    3500.000.9539947100.3911

    3510.000.7747200.30286

    3520.000.603947600.11823

    3530.000.48711

    3540.000.3611

    mz1020m_v

    0000

    0.0207267830.173351280.0659488560.020726783

    0.325975770.457873490.348586810.10928668

    1.76554511.78815611.04576040.67644684

    3.35773894.64468372.9865412.0067295

    6.0842536.3668915.43041723.8815612

    6.84737555.66971745.95423965.6037685

    4.38277253.291795.7563935.5604307

    1.80888291.5488564.51467035.2118439

    0.218573350.348586812.26675643.3144011

    0.0207267830.15262450.697173621.526245

    000.239300130.47860027

    0.109286680.086675639

    0.0207267830.020726783

    00

    T1=1000s

    T2=2000s

    T3=3000s

    T4=4000s

    dzlT1

    dzlT2

    dzlT3

    dzlT4

    dzhT1

    dzhT2

    dzhT3

    dzhT4

    distance [m]

    concentration [mg/l]

    mz1020v

    xcT=1000sxcT=2000s

    5300.1677Amz=0,113500.1058

    6300.5195Vmz=0,214800.3187

    6800.8206DIFmz=0,0315500.5283

    7201.20316100.7635

    7601.59416600.9991

    8002.02217101.259

    8302.39117501.46

    8702.74517901.683

    9902.56618501.905

    10002.40420201.671

    10102.22220601.431

    10202.02620901.192

    10401.77921200.9794

    10501.61121500.7387

    10601.40221900.4938

    10701.19722400.25

    10900.9261

    11000.751

    11300.3936

    xcT=3000sxcT=4000s

    22100.0848430900.06887

    23700.252732700.2136

    24500.413933600.3513

    25200.606234400.4985

    25800.792235100.6632

    26300.96335700.8148

    26801.13836300.9772

    27401.33236901.129

    28001.49537601.273

    30401.30