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Gestão Integrada de Bacias Hidrográficas – Aula 2 de Modelação: Processos que ocorrem na Bacia

Gestão Integrada de Bacias Hidrográficas – Aula 2 de Modelação: Processos que ocorrem na Bacia. Hydrology in SWAT. Ea. R day. Q surf. Q gw ( baseflow ). W seep. The Rain. Must be measured in rain gauges. In how many? How to interpolated/extrapolated? .

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Gestão Integrada de Bacias Hidrográficas – Aula 2 de Modelação: Processos que ocorrem na Bacia

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  1. Gestão Integrada de Bacias Hidrográficas – Aula 2 de Modelação: Processos que ocorrem na Bacia

  2. Hydrology in SWAT Ea Rday Qsurf Qgw(baseflow) Wseep

  3. The Rain • Must be measured in rain gauges. In how many? • How to interpolated/extrapolated?

  4. Comparing 3 interpolation methods in Trancão THIESSEN POLYGON Inverse of the Distance Weight Regression Model

  5. Evapo-Transpiration • Depends on: • Atmospheric conditions (HR, Temperature, radiation & wind) • Available soil water (above wilting point) • Transpiration surface (Leaf Area Index – LAI)

  6. Evapo-Transpiration • Depends on plants Development and soil cover.

  7. Penman - Monteith • Rn is the net radiation, G is the soil heat flux, (es - ea) ris the vapour pressure deficit of the air, r a is the mean air density at constant pressure, cp is the specific heat of the air, D is the slope of the saturation vapour pressure temperature relationship, g is the psychrometric constant, and rs and ra are the (bulk) surface and aerodynamic resistances. http://www.fao.org/docrep/X0490E/x0490e06.htm

  8. Satellite LAI + Mohid Land = ET

  9. Percolation

  10. Water Dynamics • Richards Equation http://www.mohid.com/wiki/index.php?title=Module_PorousMedia#Water_retention

  11. Difficulties

  12. 10cm 30cm 50cm 70cm Teores de água simulados – Gráficos Tempo/Profundidade Tempo

  13. ETR P-V P-V P-V Chuva 1º ANO 2º ANO 3º ANO Rega 50cm O-I O-I O-I 35cm 15cm P-V Efeito da ETR, chuva e rega nos teores de água Primavera-Verão O-I Outono-Inverno

  14. MOHID LandWatershed Water Content Runoff Rain Intensity IST – MARETEC 2008

  15. Runoff • Is the Rain that does not infiltrate. • Flows at soil surface, can infiltrate (and sometimes exfiltrate. • Flow is controlled by friction.

  16. Scientific Modules that must compose an integrated model • Hydrology • Vegetation (evapotranspiration, nutrients, pesticides, erosion,….) • Mineralisation of Organic matter in the soil (bacterial loop) • Irrigation • Salts dynamics/chemical equilibrium • Rivers, • Reservoirs/lakes, • Estuaries and Coastal Lagoons.

  17. Types of Models • All models compute Evapo-transpiration on the same way. Differences on results depend on the detail of the input data. • Process oriented models (e.g. Hydrus, Mohid, Mike, RZWQM) compute percolation using the Richards Equation. They need fine grids. • Other models use coarse grids and empirical formulations to compute flow (e.g. SWAT, HSPF, BASINS).

  18. Technical modules required • Meteorological data processor, • Climate (seasonal/daily solar evolution), • GIS, • Chemical Equilibrium, • Plants Optimal Growth, • Management Practices, • Graphical interfaces.

  19. Vegetation Module • Production of plants is the major role of catchments. • Diffuse pollution is mostly due to plant growth improvement: • Fertilisation, Phyto-sanitation, irrigation.

  20. Nutrient Pathways (Nutrient cycle)

  21. Soil Organic Matter http://www.fao.org/docrep/009/a0100e/a0100e05.htm

  22. CO2 N2 CH4 NH4+ Psol LABILE OM REFRACTORY OM NO3- ANAEROBIC BIOMASS AEROBIC BIOMASS CO2 Pfix Psol AUTOTROPHIC BIOMASS NH4+ NH3 Urea Soil Nutrient Model

  23. Overgrazing also compromises OM

  24. More information • http://www.mohid.com/wiki/ • http://en.wikipedia.org/wiki/MOHID_Land

  25. 1D Drainage network 2D Overland flow 3D Porous Media Precipitation Variable in Time & Space Distributed vs partially distribuited models MOHID Land SWAT HRU CN, Lag time Watershed picture to farm plots; Vegetation and Erosion Flush events

  26. Processos de qualidade da água em Rios CO2 O2 Nitrato Respiração Amónia Nutrientes Ortofosfato Consumo Sílica Bactérias Produtores Primários Excreção Morte Detritos / MO Consumo Deposição Sedimentos Produtores Secundários

  27. Hydrodynamics • Kinematic wave equation • (equilibrium between gravity and friction) • Trapezoidal shape for channels in both models • Rchisthehydraulicradius for a givendepthofflow (m), • slpchistheslopealongthechannellength (m/m), • n isManning’s “n” coefficient in channel • vcistheflowvelocity (m/s). If inertia is important:

  28. MOHID LandWatershed WaterContent Runoff Rain Intensity IST – MARETEC 2008

  29. CheianaRibeira de Algés (antes da urbanização)

  30. MOHID Land River Sediment Rain Intensity WQ models in river IST – MARETEC 2008

  31. SWAT: Percolation • wperc,lyis the amount of water percolating to the underlying soil layer on a given day (mm H2O), • SWly,excessis the drainable volume of water in the soil layeron a given day (mm H2O), • Δtis the length of the time step (hrs), • TTpercis the travel time for percolation (hrs). • SATlyis the amount of water in the soil layer when completely saturated (mm H2O), • FClyis the water content of the soil layer at field capacity (mm H2O), • Ksatis the saturated hydraulic conductivity for the layer (mm·h-1).

  32. Lateral Flow

  33. Base flow • Qgw,iis the groundwater flow into the main channel on day i (mm H2O), • Qgw,i-1 is the groundwater flow into the main channel on day i-1 (mm H2O), • αgwisthe baseflow recession constant, • Δt is the time step (1 day), and • wrchrgis theamount of recharge entering the aquifer on day i (mm H2O).

  34. CN – Curve Number (0% -100% runoff) Run Off • O CN is a function of: i) permeability, ii) land use and iii) previous soil water content. CN can change between 0.0 (no runoff) and 100 (all precipitation transformed into runoff).

  35. Run Off • S – Soil water retention parameter (mm H2O) • Knowing Qsurf (acumulated runoff) it is possible to estimate infiltration

  36. Bacia do Sado (Plano de Bacia) IST- MARETEC 2009

  37. Delineação • Com base na topografia foram geradas 700 sub-bacias para a RH6 com áreas entre 0.001 km2 e 100 km2 • Sub-bacias foram geradas em função das massas de água 1

  38. Flow Precipitation IST- MARETEC 2009 1

  39. Áreadrenadaporestação de caudal

  40. Definição de HRU Cada sub-bacia comporta-se como uma Unidade de Resposta Hidrológica (HRU) com o mesmo uso de solo, tipo de solo e declive 1

  41. Coupling with Mohid-Water

  42. Águas de Transição: Tipologias e massas de água • RH6 • Tipologia A2 • Estuário mesotidal homogéneo com descargas irregulares de rio • Estuário do Sado • 6 massas de água • Estuário do Mira • 3 massas de água IST- MARETEC 2009 8

  43. Estuário do Sado: Massas de Água IST- MARETEC 2009 28

  44. Poucos dados - estações da Sado WB1 Poucos dados - estações da Sado WB2 Poucos dados - estações da Sado WB2 (individualmente e com a média das estações)

  45. Canal de Alcácer IST- MARETEC 2009

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