Qsurf Rday Ea Qgw (baseflow) Wseep

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

Inverse of the Distance Weight Regression Model THIESSEN POLYGON

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

Depends on plants Development and soil cover.

R n is the net radiation, G is the soil heat flux, (e s - e a ) ris the vapour pressure deficit of the air, r a is the mean air density at constant pressure, c p is the specific heat of the air, D is the slope of the saturation vapour pressure temperature relationship, g is the psychrometric constant, and r s and r a are the (bulk) surface and aerodynamic resistances.

Richards Equation on

10cm 30cm 50cm 70cm Tempo

Primavera-Verão Outono-Inverno O-I P-V Chuva 1º ANO2º ANO3º ANO Rega O-I 50cm 35cm 15cm P-V ETR

Rain Intensity Water Content Runoff IST – MARETEC 2008 MOHID Land Watershed

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

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.

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).

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

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

NH 4 + REFRACTORY OM CO 2 Psol CO 2 Psol N 2 Pfix LABILE OM AEROBIC BIOMASS ANAEROBIC BIOMASS NH 4 + CH 4 AUTOTROPHIC BIOMASS NO 3 - Urea NH 3

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

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

Kinematic 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 channel vc is the flow velocity (m/s). If inertia is important:

Rain Intensity Water Content Runoff IST – MARETEC 2008 MOHID Land Watershed

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

w perc,ly is the amount of water percolating to the underlying soil layer on a given day (mm H2O), SW ly,excess is the drainable volume of water in the soil layeron a given day (mm H2O), Δt is the length of the time step (hrs), TT perc is the travel time for percolation (hrs). SAT ly is the amount of water in the soil layer when completely saturated (mm H2O), FC ly is the water content of the soil layer at field capacity (mm H2O), K sat is the saturated hydraulic conductivity for the layer (mm·h-1).

Q gw,i is the groundwater flow into the main channel on day i (mm H2O), Q g w,i-1 is the groundwater flow into the main channel on day i-1 (mm H2O), α gw isthe baseflow recession constant, Δt is the time step (1 day), and w rchrg is theamount of recharge entering the aquifer on day i (mm H2O).

A High infiltration rates. B Moderate infiltration rates. C Low infiltration rates. D Very 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).

Knowing Q surf (acumulated runoff) it is possible to estimate infiltration S – Soil water retention parameter (mm H 2 O)

IST- MARETEC 2009

1 1. Com base na topografia foram geradas 700 sub-bacias para a RH6 com áreas entre km2 e 100 km2 2. Sub-bacias foram geradas em função das massas de água

IST- MARETEC 2009 Precipitação 1 Precipitation Flow

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

IST- MARETEC 2009 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 8

IST- MARETEC

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)

IST- MARETEC 2009 Canal de Alcácer