PEST - Model-Independent Parameter Estimation and Uncertainty Analysis

Surface Water Utilities

TSPROC functional blocks Other members of the Surface Water Utility suite PEST and HSPF

The most important of the surface water utilities is TSPROC. TSPROC is a time-series processor, built for use in the calibration context. It facilitates construction of a calibration dataset based on a complex multi-component objective function. Not only does it undertake the necessary processing of field data and corresponding model outputs required for calculation of such a multi-component objective function; it automates the generation of an entire PEST input dataset that implements the calibration process.

Input to TSPROC is provided through a series of user-prepared "data blocks". Each such block instructs TSPROC to undertake a certain processing task, and provides the values of variables that it must employ in carrying out that task. These blocks are listed in the following table.

A special version of the popular HSPF program, optimized for use with PEST, is also available. See the downloads page.

TSPROC functional blocks

Other members of the Surface Water Utility suite are listed below.


HSPF is a comprehensive, conceptual, continuous watershed simulation model designed to simulate all the water quantity and water quality processes that occur in a watershed, including sediment transport and movement of contaminants. Although it is usually classified as a lumped model, it can reproduce spatial variability by dividing the basin into hydrologically homogeneous land segments, simulating runoff for each land segment independently using different meteorological input data and watershed parameters.

HSPF can be obtained from the USGS surface water modeling software website.

A more up-to-date version can be obtained from AquaTerra Consultants.

When using PEST with HSPF it is best to use a modified version whose data input protocol has been slightly altered for easier data transfer between PEST and HSPF. You can download such a version (modified from version 12 of HSPF) from the PEST downloads page or from Aqua Terra Consultants.

TSPROC (from the PEST surface water utilities) makes it easy to use PEST with HSPF. Using TSPROC you can do the following.

  1. Automate the construction of PEST input files for calibration of HSPF; whether you are calibrating against a handful of observations or thousands of observations, setup time can be reduced to minutes.
  2. Formulate a calibration process based on a multi-component objective function including monthly volumes, exceedence fractions, baseflow fractions, and other statistics.
  3. Adjust observation weights on an individual observation or observation group basis with ease, irrespective of the number of observations featured in the calibration dataset.
  4. Calibrate multiple watershed models simultaneously, introducing advanced regularization to enforce regional parameter relationships without compromising goodness of fit.
  5. Explore the uncertainty of key model predictions using PEST's linear or nonlinear uncertainty analysis tools.

A comparison between modeled and observed flows over part of a 16 year calibration period.

A comparison between modeled and observed monthly volumes over the entire 16 year calibration period.

A comparison between modeled and observed exceedence probabilities.

Null-space Monte Carlo analysis allows rapid generation of a suite of parameter sets, all of which calibrate a model.

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