The BROOK2 Hydrologic Model

[Last revised - November 10, 2005]

Download BROOK2 documentation as a Word 2000 document.

BROOK2 is a deterministic, lumped parameter model of daily snow accumulation and melt, interception, transpiration, soil evaporation, soil water, and streamflow for forest land. It is characterized by using Hamon PE and a lumped root zone. Streamflow is from source-area stormflow and drainage via a first-order groundwater reservoir. Input to the model is daily mean temperature and precipitation. Leaf area index (LAI) and stem area index (SAI) are important parameters. A number of publications report results using BROOK2. BROOK90 is a newer model based on BROOK2. However, BROOK2 is a much simpler model than BROOK90, and may do just as well or better than BROOK90 in simulating streamflow from small forested watersheds. However, BROOK2 cannot simulate water movement down through a layered soil profile; BROOK90 can.

The original BROOK hydrologic model was developed in Fortran-IV for small forested watersheds and published in 1978. BROOK2 is a Fortran-77 version of BROOK, produced in 1983. BROOK2 was later translated by Keith Eshleman into Microsoft Fortran Version 3 for running under DOS on a PC. Both the standard version and the PC version are freeware; they can be downloaded from here (see below) and may be freely used and copied. Users may be interested in a history of the BROOK models.

Documentation for BROOK2 was originally published as Federer, C.A. and D. Lash. 1978. BROOK: A hydrologic simulation model for eastern forests. University of New Hampshire Water Resources Research Center Research Report 19, 94 p. Durham, New Hampshire, U.S.A. (revised 1983). This has long been out of print. As of November 2005, this documentation, with minor revisions, can be downloaded as a Word 2000 document.

A version known as BROOK6 is described in Miller, D.R., M.J. Focazio, M.A. Dickinson, and W.E. Archey. 1988. A user's guide to a model for estimating the hydrologic effects of land use change. Cooperative Extension Service, Univ of Massachusetts and Univ of Connecticut. This can be obtained from Department of Natural Resources, Box U-87, University of Connecticut, 1376 Storrs Road, Storrs CT 06265. BROOK6 is written in BASIC and uses readily obtainable information about a watershed to choose parameter values for the model. Compass Brook does not support BROOK6.

For comments and questions, email me at

BROOK2 Standard Version

The standard version is designed to run on any machine that has a Fortran-77 compiler. Compilation is necessary. The program may be freely modified. The file B2STD.ZIP, which may be downloaded from here, contains

All these are ASCII text and can be read and printed.

Possible compile problems:

BROOK2 PC Version

The PC Version runs on a PC with DOS 3.3 or higher. The file B2PC.ZIP, which may be downloaded from here, contains

MAIN4 starts by asking for file names and unit numbers. Responses could be:

The file 'outputfilename.ext' must already exist and will be overwritten. EDLIN 'outputfilename.ext' followed by E, will create the file.
Using unit numbers = 0 will expect input from the keyboard and/or put output to screen. However, this is probably not a good way to run the model.

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