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Gesto Integrada de Bacias Hidrogrficas Aula 2 de Modelao: Processos que ocorrem na Bacia

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2Hydrology in SWAT

QsurfRdayEaQgw (baseflow)Wseep

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

4Comparing 3 interpolation methods in Tranco

Inverse of the Distance Weight Regression ModelTHIESSEN POLYGON5Evapo-TranspirationDepends on:Atmospheric conditions (HR, Temperature, radiation & wind)Available soil water (above wilting point)Transpiration surface (Leaf Area Index LAI)

6Evapo-TranspirationDepends on plants Development and soil cover.

7Penman - MonteithRnis the net radiation, G is the soil heat flux, (es- ea) ris the vapour pressure deficit of the air,rais the mean air density at constant pressure, cpis the specific heat of the air,Dis the slope of the saturation vapour pressure temperature relationship,gis the psychrometric constant, and rsand raare the (bulk) surface and aerodynamic resistances.http://www.fao.org/docrep/X0490E/x0490e06.htm

8Satellite LAI + Mohid Land = ET

9Percolation

10Water DynamicsRichards Equation

http://www.mohid.com/wiki/index.php?title=Module_PorousMedia#Water_retention11Difficulties

12Teores de gua simulados Grficos Tempo/Profundidade

10cm30cm50cm70cmTempo13Efeito da ETR, chuva e rega nos teores de guaPrimavera-VeroOutono-InvernoO-IP-V

Chuva

1 ANO2 ANO3 ANORega

O-IO-IO-I50cm35cm15cm

P-VP-VP-VETR14

Rain IntensityWater ContentRunoffIST MARETEC 2008MOHID LandWatershed15RunoffIs the Rain that does not infiltrate.Flows at soil surface, can infiltrate (and sometimes exfiltrate. Flow is controlled by friction.16Scientific Modules that must compose an integrated modelHydrologyVegetation (evapotranspiration, nutrients, pesticides, erosion,.)Mineralisation of Organic matter in the soil (bacterial loop)IrrigationSalts dynamics/chemical equilibriumRivers,Reservoirs/lakes,Estuaries and Coastal Lagoons.

17Types of ModelsAll 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).18Technical modules requiredMeteorological data processor,Climate (seasonal/daily solar evolution),GIS,Chemical Equilibrium,Plants Optimal Growth,Management Practices,Graphical interfaces.

19Vegetation ModuleProduction of plants is the major role of catchments. Diffuse pollution is mostly due to plant growth improvement:Fertilisation, Phyto-sanitation, irrigation.20Nutrient Pathways (Nutrient cycle)

21Soil Organic Matter

http://www.fao.org/docrep/009/a0100e/a0100e05.htm22Soil Nutrient ModelNH4+REFRACTORYOMCO2PsolCO2Psol N2PfixLABILE OMAEROBIC BIOMASSANAEROBIC BIOMASSNH4+CH4AUTOTROPHICBIOMASSNO3-UreaNH323

24Overgrazing also compromises OM

25More informationhttp://www.mohid.com/wiki/ http://en.wikipedia.org/wiki/MOHID_Land

26MOHID LandSWAT

HRU

CN, Lag timeVegetation and ErosionWatershed picture to farm plots; Flush events

2D Overland flow

PrecipitationVariable in Time & Space3D Porous Media

1D Drainage network

Distributed vs partially distribuited models27

Produtores Primrios

NutrientesNitrato Amnia Ortofosfato Slica Consumo

ConsumoExcreoMorteProdutores SecundriosDetritos / MOBactrias

DeposioSedimentos

RespiraoCO2O2Processos de qualidade da gua em Rios28HydrodynamicsKinematic wave equation(equilibrium between gravity and friction)Trapezoidal shape for channels in both models

Rch is the hydraulic radius for a given depth of flow (m),slpch is the slope along the channel length (m/m),n is Mannings n coefficient in channelvc is the flow velocity (m/s).

If inertia is important:29Rch is the hydraulic radius for a given depth of flow (m),slpch is the slope along the channel length (m/m),n is Mannings n coefficient in channelvc is the flow velocity (m/s).

Rain IntensityWater ContentRunoffIST MARETEC 2008MOHID LandWatershed30Cheia na Ribeira de Algs (antes da urbanizao)

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Rain IntensitySedimentIST MARETEC 2008WQ models in riverMOHID Land River32SWAT: Percolation wperc,ly is the amount of water percolating to the underlying soil layer on a given day (mm H2O), SWly,excess is the drainable volume of water in the soil layeron a given day (mm H2O), t is the length of the time step (hrs), TTperc is the travel time for percolation (hrs).SATly is the amount of water in the soil layer when completely saturated (mm H2O), FCly is the water content of the soil layer at field capacity (mm H2O), Ksat is the saturated hydraulic conductivity for the layer (mmh-1).

33Lateral Flow

34Base flowQgw,i is 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), gw isthe baseflow recession constant, t is the time step (1 day), and wrchrg is theamount of recharge entering the aquifer on day i (mm H2O).

35Run OffAHigh infiltration rates.BModerate infiltration rates. CLow infiltration rates. DVery low infiltration rates. CN Curve Number (0% -100% runoff) 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). 36Run OffKnowing Qsurf (acumulated runoff) it is possible to estimate infiltration

S Soil water retention parameter (mm H2O)

37IST- MARETEC 2009

Bacia do Sado (Plano de Bacia)381

DelineaoCom base na topografia foram geradas 700 sub-bacias para a RH6 com reas entre 0.001 km2 e 100 km2Sub-bacias foram geradas em funo das massas de gua

26-10-201139IST- MARETEC 2009Precipitao1

PrecipitationFlow4026-10-201140rea drenada por estao de caudal

41Cada sub-bacia comporta-se como uma Unidade de Resposta Hidrolgica (HRU) com o mesmo uso de solo, tipo de solo e declive1

Definio de HRUHRU Hidrologic Response Unit. A este da bacia temos cultura de sequeiro. A oeste temos pinhal. A sul temos carvalhos. Rega na parte central da bacia e no canto inferior esquerdo.Solos mediterrneos pardos (px) a este da bacia, Litossolos (ex) a sul e podzois (pz) na zona de pinhal.26-10-201142Coupling with Mohid-Water43guas de Transio: Tipologias e massas de guaIST- MARETEC 2009RH6Tipologia A2Esturio mesotidal homogneo com descargas irregulares de rio Esturio do Sado 6 massas de gua Esturio do Mira 3 massas de gua

844Esturio do Sado: Massas de guaIST- MARETEC 2009

2845Os valores variam muito com o parmetro podendo variar entre 200 e 2000. No caso do fito que para ns ser o parmetro central da clissificao o nermode valores disponveis da ordem de 400. O trabalho que terminamos foi agregar os dados por massa de gua de forma a ser possvel um primeira avaliao do estado tendo por base as condies de referncia anteriormente apresentadas. Excepto no canal de Alccer todas as massas de gua podem ser consideradas boas. Excepto o canal de Alccer. No entanto, as contas feitas assumem um peso igual para todos os valores. O que no caso do Canal de Alccer pode levar a grandes distores. Est em fase de elaborao um mtodo permita determinar o percentil 90 considerando a representatividade de cada estao em termos de volume. A pergunta que fica no ar se cada ponto deve ter o mesmo peso ou um peso relativo.

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Poucos dados - estaes da Sado WB1Poucos dados - estaes da Sado WB2Poucos dados - estaes da Sado WB2 (individualmente e com a mdia das estaes)46IST- MARETEC 2009

Canal de Alccer

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