1 / 31

The CATchment HYdrology (CATHY) Model

UNESCO-IHP Water Programme for Environmental Sustainability - WPA II. The CATchment HYdrology (CATHY) Model. Working Group: Claudio Paniconi and Mauro Sulis INRS-ETE, University of Quebec, Canada Mario Putti and Matteo Camporese University of Padova, Italy

wesley
Download Presentation

The CATchment HYdrology (CATHY) Model

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. UNESCO-IHP Water Programme for Environmental Sustainability - WPA II The CATchment HYdrology (CATHY) Model Working Group: Claudio Paniconi and Mauro Sulis INRS-ETE, University of Quebec, Canada Mario Putti and Matteo Camporese University of Padova, Italy Stefano Orlandini, Giovanni Moretti, Maurizio Cingi and Alice Cusi University of Modena & Reggio Emilia, Italy First “Climate Change...” Project Meeting, May 29 – June 4, 2009, Brazil

  2. Context Surface and subsurface waters are not isolated components of the hydrologic system, but interact in response to topographic, soil, geologic, and climatic factors. • Groundwater seepage can take the dual role of source and sink: • Groundwatermay seep out from shallowaquifer and feed networks of irregular channels. • Surface water may seep back into the ground, possibly depleting streams until they run dry.

  3. Context • The interaction of groundwater and surface flow is a key focus of interest for: • Water resources management (under the effects of climate and land use and demographic changes) • Water quality (e.g., role hyporheic fluxes in aquatic habitats) • Geomorphology (e.g., action of groundwater seepage on channel initiation) A number of modeling tools and approaches have been developed for studying coupled surface water-groundwater systems: Three-dimensional equation for variably saturated subsurface flow, i.e., Richards equation, coupled with a one- or two-dimensional approximation of the Saint-Venant equations for overland and channel flow, represent the current state-of-the-art in catchment-aquifer models.

  4. Outline • Model description: • Mathematical formulation • Numerical discretization • Surface–subsurface interactions • Surface flow conceptualization • Test cases and applications • Data Requirements

  5. generalstorageterm [1/L]:  = SwSs + f(dSw/d) Swwater saturation = /s[/] volumetricmoisturecontent [L3/L3] s saturatedmoisturecontent[L3/L3] Ssspecificstorage [1/L] porosity (= sif no swelling/shrinking) pressure head [L] ttime [T] Kssaturatedconductivitytensor [L/T] Krwrelative hydraulicconductivity [/] zzero in x and y and 1 in z direction z vertical coordinate +ve upward [L] qs subsurface equation coupling term (more generally, source/sink term) [L3/L3T] h ponding head (depth of water on surface of each cell) [L] s hillslope/channel link coordinate [L] Q discharge along s [L3/T] ck kinematic wave celerity [L/T] Dh hydraulic diffusivity [L2/T] qL surface equation coupling term (overland flow rate) [L3/LT] Model description: Mathematical formulation (1) (2) (1) Paniconi & Wood, Water Resour. Res., 29(6), 1993 ; Paniconi & Putti, Water Resour. Res., 30(12), 1994 (2) Orlandini & Rosso, J. Hydrologic Engrg., ASCE, 1(3), 1996 ; Orlandini & Rosso, Water Resour. Res., 34(8), 1998 (1)+(2) Bixio et al., CMWR Proceedings, 2000 ; Putti & Paniconi, CMWR Proceedings, 2004

  6. Model description: Numerical discretization • Surface: • PDE of the kinematic wave solved by a finite difference (FD) scheme • Numerical dispersion arising from the truncation error of the scheme is used to simulate the physical dispersion • Unconditional stability reached by matching numerical and physical diffusivities through the temporal weighting factor used to discretize the kinematic wave model

  7. Model description: Numerical discretization • Subsurface: • PDE solved by a three-dimensional finite element (FE) spatial integrator and by a weighted finite difference (FD), i.e. Euler or Crank-Nicolson, scheme in time • Nonlinearity arising from the storage (Sw) and conductivity Krw(Sw) terms are handled via a Picard or Newton linearization scheme • Time varying boundary conditions: prescribed head (Dirichlet type) or flux (Neumann type), atmospheric fluxes, source/sink terms, and seepage faces

  8. Model description: Surface–subsurface interactions The coupling between the land surface and the subsurface is handled by an automatic boundary condition (BC) switching algorithm acting on the source/sink terms qs(h) and qL(h,). The coupling term is computed as the balance between atmospheric forcing (rainfall and potential evaporation) and the amount of water that can actually infiltrate or exfiltrate the soil. The switching check is done surface node by surface node in order to account for soil and topographic variability. The switching check is done at each time the surface equation is solved (according to the values of ponding heads at the surface) and at each subsurface time or iteration.

  9. Model description: Surface–subsurface interactions

  10. Unified Flow Direction Algorithm • The mathematical formulation implemented is based on the use of: • Triangular facets introduced by Tarboton (1997, WRR) • Path-based analysis introduced by Orlandini et al. (2003, WRR) • Plan curvature computation introduced by Zevenbergen and Thorne (1987, ESPL)

  11. Unified Flow Direction Algorithm Orlandini et al. (2003, WRR) Orlandini and Moretti (2009, JGR)

  12. Unified Flow Direction Algorithm Orlandini and Moretti (2009, WRR)

  13. Validation Using Contour Elevation Data Moretti and Orlandini (2008, WRR)

  14. Drainage Basin and Drainage Slope Orlandini and Moretti (2009, WRR)

  15. Prediction of the Drainage Network

  16. Hydraulic Geometry (Leopold and Maddock, 1953)

  17. Parameterization of Stream Channel Geometry(Channels and Hillslope Rivulets) Orlandini and Rosso (1998, WRR)

  18. Parameterization of Conductance Coefficients(Channels and Hillslope Rivulets) Orlandini (2002, WRR)

  19. Diffusion Wave Modeling: Mathematical Model Kinematic wave model Diffusion wave model

  20. Diffusion Wave Modeling: Parameterization of the Drainage System Gauckler-Manning-Strickler Equation Incorporating the variation of stream channel geometry Incorporating the variation of conductance coefficient and stream channel geometry

  21. Diffusion Wave Modeling: Constitutive Equations Flow Rating Curve Kinematic Celerity Hydraulic Diffusivity

  22. Diffusion Wave Modeling: Muskingum-Cunge Method with Variable Parameters

  23. Diffusion Wave Modeling: Muskingum-Cunge Method with Variable Parameters • The Muskingum-Cunge method with variable parameters is: • Unconditionally stable (Dn = Dh). • Accurate for Courant numbers not too far from 1 (∆s≈ck ∆t). • Independent of structural parameters ∆s and ∆t. • (Cunge, 1969, JHR; Ponce, 1986, JHE; Orlandini and Rosso, 1996, JHE)

  24. Test cases and applications 1D sloping plane with homogeneous subsurface* • Sloping plane catchment (400 m x 320 m) • S0=0.0005 (slope) • Dx=Dy=80 m (spatial discretization) • Ts = 300 min (simulation time) • Tr = 200 min (rainfall time) • Td = 100 min (recession time) • qr = 20 mm/h (rainfall intensity) • Saturation excess (Dunnianprocess): • Ksat=41.7 mm/h • Water table heights: 0.5 and 1.0 m • Excess infiltration (Hortonian process): • Water table height: 1.0 m • Ksat=0.417 and 4.17 mm/h * Results in agreement with Kollet & Maxwell, Adv. Water. Res., 29, 2006.

  25. Test cases and applications: Saturation excess

  26. Test cases and applications: Infiltration excess

  27. Test cases and applications Application of CATHY model in a climate change frameork to the 720 km2 des Anglais catchment located in southern Quebec - Data provided by the Canadian Regional Climate Model (CRCM V4.2.0) • - Precipitation (rain, snow) • Temperature (max, min) • Data provided for a 45-km horizontal grid-size mesh with a daily temporal resolution: • Model calibrated to distributed (water table) and aggregated (flow rate) data

  28. Test cases and applications

  29. Test cases and applications

  30. Data Requirements: Catchment Properties • Grid-based or contour-based digital elevation models • Soil retention characteristics • residual and saturated water content • pore-size distribution index • saturated soil matrix potential • hydraulic conductivity • Geologic stratigraphy, bedrock depth • Land cover and use • Channel network • cartographic blue lines • cross sections • roughness coefficients • Man-made hydraulic structures

  31. Data Requirements: Hydrologic Variables • Precipitation • rainfall • occult precipitation • snow • Evaporative demand (estimated using the Penman-Monteith equation) • solar radiation • air humidity • wind speed • air temperature • barometric pressure • Streamflow • Soil moisture • Water table depth

More Related