Wencong Lai, Fred Ogden, Robert Steinke, Hernan Moreno, Nels Frazier, and Leticia PurezaDepartment of Civil & Architectural Engineering, University of Wyoming

The ADHydro Model and its Suitability for High Performance Water Resource Modeling

Motivating Questions

AbstractThe CI-WATER project is a cooperative effort to acquire hardware and develop software cyberinfrastructure to enhance accessibility of High Performance Computing for data- and computationally-intensive water resources modeling and management. One of its components is development of a large-scale, high-resolution, multi-physics, distributed water resources model suitable for operation in a massively parallel computing environment. The implementation of this model, called ADHydro, uses the Charm++ parallel programing system, which offers automatic and dynamic partitioning, load balancing and checkpointing. This model simulates important hydrologic process including: precipitation, infiltration, evapotranspiration, soil heat flux, snow melt, overland flow, channel flow, groundwater flow and water management. The model has a quasi-3D formulation that couples 2D overland flow and groundwater flow using a 1D infiltration method, which eliminates difficulties in solving the nonlinear 3D Richards’ equation. The open-source model includes well documented APIs to achieve interoperability and facilitate additions and modifications. The ADHydro model is coupled with the WRF meteorological model and the Noah-MP land surface model. Software tools have been developed for model set up and visualization of large-scale watersheds. The objective of the model is to simulate the Upper Colorado River Basin above Lake Powell for multi-decadal hydrologic studies in the contexts of water use, land use, and climate changes. An overview of the ADHydro model architecture is presented.

EPSCoREPS 1135483

http://ci-water.org/

Colorado River Basin

Streams: 467,000 km Basin Area: 288,000 km2

Area above 2700 m (9,000 ft) 14.5% Area above 3050 m (10,000 ft) 3.2% Population: 900,000 (USBR) Population depending on water > 30 M

Our CollaboratorsUpper Colorado River Basin

3rd CUAHSI Hydroinformatics Conference July 15-17, 2015, Tuscaloosa AL

What are the potential impacts of climate change on the long term water yield from the Upper Colorado River basin? How will land-use changes due to development and natural causes such as fire and the mountain pine bark beetle outbreak affect water supplies? How to build a suitable large-scale high-resolution multi-physics distributed water resources model in parallel computing environment ?

ADHydro Multi-Physics Hydrological ModelAHDydro is a high resolution multi-physics model integrating hydrologic process, engineered infrastructure, water resources polices and water management into spatially distributed simulations. The merits of the model include an innovative method for modeling vadose zone dynamics, a water management module considering reservoirs, irrigation and diversions, a coupled strategy to estimate interception evaporation and snow processes through Noah-MP.

Suitability for High Performance Water Resource Modeling Explicit finite volume method solver Groundwater and overland water explicitly coupled by vadose zone infiltration Precipitation, evapotransporation, and infiltration are treated as point processes Mass conservation numerical methods Code developed using the CHARM++ parallel programing system Well documented APIs to achieve interoperability and modular programing

Physical Process Mathematical model Governing Equations Numerical method

Precipitation WRF meteorological model[1] Compressible, nonhydrostatic Euler equations Point-scale process

ET / Snow Noah-MP land surface model[2] Surface energy balance equation Point-scale process

Infiltration 1D T-O[3] / GARTO model[4] Finite water-content method

Overland flow 2D dynamic/diffusive wave Shallow water equations (Saint-Venant equations) Explicit finite volume method

River network flow 1D dynamic/diffusive wave Explicit finite volume method

Groundwater flow 2D Boussinesq flow Explicit finite volume method

Water management Reservoirs, irrigation, and diversions

( dzdt )θ

=∂k (θ )

∂θ (1 −∂ ψ (θ )

∂ z )

∂ A∂ t

+∂Q∂ x

= qs ,∂Q∂ t

+∂Q2/ A

∂ x=−gA

∂Z∂ x

− gAS f

S y∂h∂ t

= ∂∂ x (K x h

∂H∂ x ) + ∂

∂ y (K y h∂H∂ y ) + R

References[1] Michalakes, J. et al. (2014). The weather research and forecast model: Software architecture and performance, Proceedings of the 11th ECMWF workshop on th use of high performance computing in meteorology, Reading U.K. Ed. George Mozdzynski.[2] Niu, G.-Y., et al. (2011). The community Noah land surface model with multiparameterization options (Noah-MP): 1. Model description and evaluation with local-scale measurements, J. Geophys. Res., doi:10.1029/2010JD015139.[3] Ogden et al. (2015). A new general 1-D vadose zone flow solution method. Water Resour. Res. 51, doi:10.1002/2015WR017126.[4] Lai et al. (2015). An efficient and guaranteed stable numerical method for continuous modeling of infiltration and redistribution with a shallow dynamic water table. Water Resour. Res., 51, doi:10.1002/2014WR016487.

ADHydro model architecture 2D unstructured triangular mesh Model formulation layers

ADHydro model multi-physics simulation

T-O finite water-content domain

Infiltration simulation on Youtube:

GARTO methodT-O method