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Selected Presentation from the INSTAAR Monday Noon Seminar Series.
Institute of Arctic and Alpine Research, University of Colorado at Boulder.http://instaar.colorado.edu
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25 Nov. 2002 Scott Peckham, INSTAAR, Email: scott.peckham@colorado.edu" A new distributed hydrologic model based on ARHYTHM and RiverTools."Seminar given at INSTAAR, University of Colorado. Copyright 2002 Scott Peckham. All Rights Reserved.Peckham presentation (0.9 Mb PDF)
Selected Presentation from the INSTAAR Monday Noon Seminar Series.
Institute of Arctic and Alpine Research, University of Colorado at Boulder.http://instaar.colorado.edu
http://instaar.colorado.edu/other/seminar_mon_presentations
25 Nov. 2002 Scott Peckham, INSTAAR, Email: scott.peckham@colorado.edu" A new distributed hydrologic model based on ARHYTHM and RiverTools."Seminar given at INSTAAR, University of Colorado. Copyright 2002 Scott Peckham. All Rights Reserved.Peckham presentation (0.9 Mb PDF)
Abstract
ARHYTHM is a distributed hydrologic/thermal model that was developed by Hinzman and colleagues (Zhang et al., 1999)for use in both arctic and nonarctic watersheds. It incorporates a number of important physical processes, includingsnowmelt, evapotranspiration, precipitation, subsurface (multi-layer Darcy-law) flow, overland flow and channel flow. Thesnowmelt process can optionally be modeled with either the degree-day or energy balance method. Similarly,evapotranspiration can be modeled with either the Priestley-Taylor or energy balance method. The model is physically-based and has been tested for several watersheds on Alaska's North Slope. It consists of a geometric component thatextracts a D8 flow grid from a DEM, in addition to the dynamic modeling component.
During the past year, the dynamic component of the ARHYTHM model has been rewritten and significantly extendedusing IDL (Interactive Data Language) and endowed with a user-friendly graphical interface. This interface has beendesigned to make it easy for users to code up new methods for any of the physical processes. Rather than rewrite thenetwork extraction component, the model now draws on the powerful capabilities of RiverTools for the geometriccomponent and visualization of results. Together, RiverTools and this new version of the ARHYTHM model make apowerful hydrologic modeling toolkit.
A New Distributed Hydrologic
Model Based on ARHYTHM and
RiverTools
Dr. Scott D. Peckham
University of Colorado, Boulder
December 8, 2002
TopoFlow
Acknowledgements
Colleagues at the University
of Alaska in Fairbanks:
Matt Nolan, Larry Hinzman,
and Bob Bolton
And at the USGS in Boulder:
J. Dungan Smith and David Kinner
What is RiverTools?
What is ARHYTHM?
RiverTools is a commercially-sold application for digital terrain
and river network analysis. It is a full-featured Windows-style
program with raster and vector GIS capabilities, ability to import
many DEM formats, advanced visualization and analysis tools,
and a wide variety of additional tools for working with DEMs
and flow grids. (www.researchsystems.com)
ARHYTHM is a spatially-distributed hydrological model that
incorporates thermal processes for use in the Arctic. It is physically
based and is written in Fortran.See Zhang, Z., Kane, D.L., Hinzman, L.D. (2000) Development and application of a
spatially-distributed Arctic hydrological model and thermal process model (ARHYTHM),
Hydrol. Proc., 14, 1017-1044.
Design Criteria for TopoFlow
¸ User-friendly interface
¸ User-extendible
¸ Open-source code
¸ Structured, consistent, clean
¸ Different timesteps for processes
¸ Multiple output options:
Grid sequences, hydrographs for
multiple outlets, etc.
¸ Flexible input options:
Any input variable can be a scalar or grid.
Note: IDL’s dynamic data typing is perfect for this.
Overall Design Paradigm
Physical Process: (e.g. Snowmelt, ET, Overland Flow, Channel Flow)
Method: (None/Simple/Complex, e.g. None, Degree-Day, Energy Balance)
Formulas: (These define the method. Need enough to solve for all
the output variables. Implemented as functions.)
Variables: (Input/Output, Scalar/Grid, Deterministic/Random)
Other Issues:
Timesteps
Stopping Criteria
Output Methods
Multiple Methods per Process
Degree-DayNone Energy BalanceSnowmelt
NonePriestley-Taylor Energy BalanceEvapotran.
Kinematic WaveDynamic WaveChan. Flow None
Each method has a similar set of dialogs to specify
or collect input and output variables. Any process
can be turned off.
TopoFlow Main Dialog
Snowmelt: Energy Balance Dialog
Uniform Precipitation Dialog
Subsurface Flow Dialog
Output Methods
Trapezoidal Channel Cross-Sections(attributes can depend on HS Order)
Flow Resistance Options: Manning’s Formula (n)
Law of the Wall (z0)
Special Cases: Rectangular: width = 0
Triangular: angle = 0
Treynor Watershed Surface Plot
Treynor Watershed Surface Plot
Treynor Watershed, Iowa (0.43 sq km)
Simulated Hydrograph for
Treynor Basin and 6/7/67 Storm
Simulated Hydrograph for Treynor
Basin and 6/20/67 Storm
Simulated Hydrograph for Treynor
Basin from Steady Rain
Treynor Hydrographs vs. Data
Distributed Discharge Animations
The animation could not be included
In this PDF document, but might be
Available on the INSTAAR website.
Extending TopoFlow:Steps for Adding a New Method
Suppose a user with basic programming skills wants to add a
new method for modeling a given physical process.
1. Add string to the droplist of methods in code for main dialog.
2. Add name of routine to call when that method is selected.
3. Add any new input variables the method needs to the structure
which contains all the input variables for given method.
4. Edit the “method caller” routine to add the new method.
5. Starting with code for an existing method’s GUI (viewed as
a template), edit it to collect input variables that are needed by
the new method.
6. Write a set of functions corresponding to the formulas that
define the new method. Model these after examples.
Summary
- TopoFlow is a new, user-friendly and user-extendible
toolkit for spatially distributed hydrologic modeling.
- Although similar in spirit to models like CASC2D
and MMS, it offers several advantages, such as the
ability for any input variable to be provided as a scalar
to be distributed uniformly or as a spatial grid.
Similar support for grid sequences is planned.
- It’s intuitive, open-source, structured design provides
an environment for both research and education.
UAF Campus
Flow Lines for Treynor Watershed
High-Level Pseudocode- Create input files with RiverTools
- Launch the GUI and collect all input variables
- Call Main Program
For each timestep do begin
For each physical process do begin
If it is time to update the process then
Get contributions using formulas for chosen method
Endfor
Add up the contributions
Update dynamic variables
Save selected variables in files
Endfor
- Exit Main Program
- Create plots using the output files
Measuring Input Variables
Anatomy of TopoFlow
Main Dialog
Main Dialog Event Handler
Main Program
For each method:
Dialog to collect input variables (+ Event handler and Help)
Dialog to specify output variables (+ Event handler and Help)
Dialog to list formulas for the method
For each physical process:
“Method Caller” routine (called by Main Program)
Data structure that stores all parameters for that process.
A Collection of Utilities
And Thank You, Starbucks
A programmer is a machine for
turning coffee into software
A mathematician is a machine for
turning coffee into theorems.
Simulated Hydrograph for Treynor
Basin from Snowmelt
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