Hydro Models Contract

Final Draft, COMP 145 Spring 1999

February 11, 1999


Contractor Team Members:
Peter Chapman
Maria Doyle, Producer
Hank Hoffmann, Technical Director
Jack Tang
Skip Walker

Larry Band

David Stotts


The geography department specifically Dr. Larry Band's department is currently operating a spatially distributed model of watershed carbon, water and nutrient dynamics. This model is called RHESSys (Regional HydroEcological Simulati on System). Its development and application has been funded by a combination of NASA, NOAA and Canadian Government agencies over the last 10 years. The model produces the spatial distribution of watershed stream flow, ecosystem productivity (net carbon ac cumulation, forest growth) and nutrient (e.g. nitrogen) cycling.

The model is currently written as a set of subroutines, some of which simulate major processes (e.g. photosynthesis, evaporation, soil water flow, nutrient cycling) and some of which control, organize, and combine results. Output includ es time series of stream flow, evaporation, soil water content and other variables that can be aggregated to the full watershed from each simulation unit, or mapped at time slices for the full landscape (as surfaces) at the level of each unit. The contrac tors agree to implement the specifications of Hydro Models identified below in the primary requirements. The contractors also agree to implement the secondary requirements as time permits over the Spring 1999 semester.

Primary Requirements

1.Conversion of the current C code into an object oriented code in C++. This conversion would make the model easier to substitute in different algorithms for each of the major processes.

2.Provision of a JAVA interface to act as a Graphical User Interface (GUI) for assembling the necessary input data, carrying out preprocessing and model parameterization. Examples of this data are the World file and the TEC file.

3.Conform to client's current coding conventions and guidelines.

4. Maintain current ASCII output capabilities.

Secondary Requirements

1.Add visual output capabilities to the Java interface described in the primary requirements section (#2). These capabilities may include:

  1. Output to selected variables as arrays at specified time intervals.
  2. Write to output files and pipe to graphics display as standalone.

2. Add capability to output selected variables as arrays at specified time intervals. Write to output files and pipe to graphics display as standalone.


Resources Required by the Contractor Team Members

Hardware Requirements:

Access to machines running the UNIX operating system and other UNIX variants.

Software Requirements:

1. A working version of the Regional Hydrologic Simulation System (RHESSys) version 4.6, possibly on a compressed (tar) format.

2. A windowed UNIX environment in which to test each product interface.

3. A working program and its source code. Tested and known (at least expected) results.

Documentation Requirements:

Version 4.6 of the Regional Hydrologic Simulation System (RHESSys) manual.


Private directory space for the members of the Hydro Models Team.


1. Given the Team Membersí unfamiliarity with RHESSys 4.6 there may be some difficulty establishing known good results for the purposes of testing the product described in Primary Requirements clause 1.

2. Given the size and complexity of RHESSys 4.6 and the fact that some of the team members are unfamiliar with the C language, there is a steep learning curve that must be overcome to become productive on this project. This learning cur ve may interfere with our ability to meet deadlines.




1. World File: Entire landscape structure is described and parameterized in this file which is input into the RHESSys simulation.

2. TEC File: RHESSys execution is based on a temporal event or TEC file which must be specified in the command line.

3. Tar: Compressed file

Signatures of Agreement

We sign with the understanding that this is a preliminary contract, which may be revised with our mutual agreement.

Hydro Models Team:

Peter Chapman

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Maria Doyle

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Hank Hoffmann

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Jack Tang

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Skip Walker

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Larry Band

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David Stotts

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