B A T H T
U B -
Version 6.1
|
Program Description
BATHTUB is
designed to facilitate application of
empirical eutrophication models
to reservoirs or lakes. The program formulates steady-state water
and nutrient mass balances in a spatially
segmented hydraulic network
that accounts for advective transport, diffusive transport,
and nutrient sedimentation. Eutrophication-related water quality conditions
(expressed in terms of total phosphorus, total
nitrogen, chlorophyll a,
transparency, organic nitrogen, non-ortho-phosphorus, and hypolimnetic
oxygen depletion rate) are predicted using
empirical
relationships previously developed and tested for
reservoir applications (
Walker, 1985 ). To provide regional perspectives on reservoir water quality,
controlling factors, and model performance, BATHTUB can also be configured for
simultaneous application to
collections or networks of reservoirs
. As
described in Chapter 1 ( Walker, 1999 ),
applications of the program would normally follow use of the
FLUX program for reducing tributary
monitoring data and use of the PROFILE program for reducing pool monitoring
data, although use of the data reduction programs is optional if independent
estimates of tributary loadings and/or average pool water quality conditions
are used.
The program generates output in various tabular and graphic formats , as appropriate for specific applications. Descriptions of underlying theory, program operation , model options , output variables , application scenarios , sample input files , and recent updates are attached. T he help screens provided with the model are not intended to be comprehensive. The user is referred to Walker (1985) for a description of the model derivation and to Walker, 1999 (Chapter 1) for a discussion of basic modeling concepts and data requirements.
Basic elements defining each application include:
The functions of the program can be broadly classified as diagnostic or predictive:
Diagnostic:
Predictive:
Predicted confidence limits can be calculated for each output variable using a first-order error analysis scheme that incorporates effects of uncertainty in model input values (e.g., tributary flows and loadings, reservoir morphometry, monitored water quality) and inherent model error . While BATHTUB offers a variety of empirical models that have been pre-calibrated to CE reservoir data ( Walker, 1985 ), the program allows includes a routine for calibrating the model to reservoir-specific monitoring data. If sufficient data are available, calibration may reduce prediction error.
Walker, William W., “Empirical Methods for Predicting Eutrophication in Impoundments - Report 1: Data Base Development", "prepared for Office, Chief of Engineers, U.S. Army, Washington, D.C., Technical Report E-81-9, U.S. Army Corps of Engineers, Waterways Experiment Station, Vicksburg, Mississippi, May 1981.
Walker, William, W., "Empirical
Methods for Predicting Eutrophication in Impoundments - Report 2: Model
Testing", prepared for Office, Chief of Engineers, U.S. Army, Washington, D.C.,
Technical Report E-81-9, U.S. Army Corps of Engineers, Waterways Experiment
Station, Vicksburg, Mississippi, September 1982.
Walker, William W., "Empirical
Methods for Predicting Eutrophication in Impoundments - Report 3: Model
Refinements", prepared for Office, Chief of Engineers, U.S. Army, Washington,
D.C., Technical Report E-81-9, U.S. Army Corps of Engineers, Waterways
Experiment Station, Vicksburg, Mississippi, Draft 1983, published March
1985.
Walker, William W., Simplified Procedures for
Eutrophication Assessment & Prediction: User
Manual Instruction Report W-96-2 USAE Waterways Experiment
Station, Vicksburg, Mississippi, 1996 (Updated September
1999)
Technical Support
Download Current Version of
Software & Documentation:
http://www.wes.army.mil/el/elmodels/emiinfo.html
Dr. David
Soballe
e-mail: David.M.Soballe@erdc.usace.army.mil