TopoFlow Main
Download: Code
TopoFlow Hydrologic Model
Note:
TopoFlow 1.1 is now available and a new tutorial has been
added to the Docs folder. This version has a new, wizard-style
graphical interface, Green-Ampt infiltration, an improved shallow
subsurface flow module, support for flow diversions and much more. It
also allows almost any input variable to be specified as a scalar, a time
series, a single grid, or a grid sequence. Follow the Code link to source
code and SAV files.
TopoFlow is a powerful,
spatially-distributed hydrologic model with
a user-friendly point-and-click interface. Its main purpose is to
model many different physical processes in a watershed with the
goal of accurately predicting how various hydrologic variables will
evolve in time in response to climatic forcings. Time evolutions
for single pixels (such as hydrographs), collections of pixels, or
entire grids (as animations) are all supported as output options.
The currently supported physical processes are:
Snowmelt (Degree-day or energy balance method) Precipitation (uniform or varying in space/time) Evapotranspiration (Priestley-Taylor or energy balance) Infiltration (simple Green-Ampt so far) Channel/overland flow (Manning or Law of Wall) Shallow subsurface flow (Darcian, multiple uniform layers) Flow diversions (sources, sinks and canals)
Processes such as sediment and contaminant
transport and landform evolution are planned for future releases.
For each physical process, the user selects a "method" to be used to
model that process from a droplist of options, and then specifies the
input data that is required for that method and the output variables
that are of interest. TopoFlow is designed so that users can use
existing methods, share methods with others, or add their own methods
and incorporate them into the graphical user interface. A method
called "None" is always available to turn off any given physical
process, and cleanly-written templates are provided to simplify the
task of adding new methods.
TopoFlow is written in a high-level, array-based programming
language called IDL (Interactive Data Language). IDL is the
flagship product of Research Systems, Inc. (RSI), a wholly owned
subsidiary of Kodak. Advanced features like:
Dynamic data typing (very useful for TopoFlow) Associated input/output (to conserve memory) Fast array processing Transparent memory management Built-in ability to create point-and-click user interfaces Support for pointers and data structures and Easy-to-learn command syntax make IDL especially well-suited to the needs of the TopoFlow
project. Programs written in IDL are also highly portable across
computer platforms, so that TopoFlow runs almost identically on
Windows, Mac, and Unix platforms. (TopoFlow was also designed
to handle byte order issues transparently.) To run TopoFlow, you need
one of the following: (1) a licensed copy of IDL 6.0, (2) a licensed copy
of RiverTools 3.0 or (3) the IDL 6.0 Virtual Machine. The IDL 6.0
Virtual Machine is a free download that allows you to run any IDL
"SAV" file that has been compiled with IDL 6.0. A licensed copy of
IDL allows access to the IDL command line while TopoFlow is
running and creates a very flexible modeling environment.
Launched at a workshop in January 2003,
TopoFlow is the brainchild of Drs. Scott Peckham, Matt Nolan and
Larry Hinzman. Scott is a hydrologist at the University of Colorado
at Boulder, while Matt and Larry are hydrologists at the University
of Alaska in Fairbanks. Larry Hinzman is also one of the authors of
ARHYTHM, a spatially-distributed hydrological model (in Fortran) that
incorporates thermal processes for use in the Arctic.
Many of the physical process methods used in TopoFlow are based
on those in ARHYTHM, as documented by Zhang et el. (2000). ARHYTHM has
been validated with data for many Arctic watersheds. TopoFlow
has been designed to be easily extended by a user community of
hydrologists.
TopoFlow can be installed as a plug-in to RiverTools and can
take advantage of some of the capabilities of RiverTools
when both are present. RiverTools is a user-friendly, point-and-click
environment for the GIS analysis of digital terrain, watersheds and
river networks. A summary of key functionality is available on a
Fact Sheet and Image Gallery at the
RiverTools website
(www.rivertools.com).
RiverTools 3.0 can be purchased as a stand-alone product (written
in IDL) from Rivix, LLC.
IDL 6.0 can be purchased from
RSI. RiverTools can create a variety of
input files (grids) that are required by TopoFlow and
also has a large number of useful tools for DEM preparation, visualization,
analysis and grid editing.
TopoFlow is distributed as very clean, open-source IDL code, complete
with a user-friendly graphical user interface, context-specific help, etc.
The goal is for users to use this code as a template for contributing and
sharing new hydrological "methods" that they may develop.
Partial funding for this work has been provided by a
grant from the National Science Foundation (OPP-0229705),
which is gratefully acknowledged. Any opinions, findings,
conclusions or recommendations expressed on this website
are those of the authors and do not necessarily reflect
the views of the National Science Foundation.
Some of the following pages contain *.pdf (
Comments or concerns about the TopoFlow website? http://instaar.colorado.edu/topoflow
What is TopoFlow?
)
documents. You can read those documents with a free downloadable acrobat reader. For downloading or more information, see the acrobat webpage.
Mail to:
Scott.Peckham@colorado.edu
Copyright (C) 2003-2006 INSTAAR, Univ. of Colorado
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