Skip to main content

GUIDING PRINCIPLES FOR MODELING IN A TMDL PROCESS

Buy Article:

$17.50 plus tax (Refund Policy)

Or sign up for a free trial

Abstract:

Several reviews and evaluations of applications of the TMDL process over the past several years have identified the need for improvement in the modeling applications used to inform the process. Therefore, as part of a project funded by the Water Environment Research Foundation (WERF) to identify and make recommendations for improving the TMDL process, we have compiled a set of guiding principles for modeling used to support a TMDL. Presented below are some principles of good modeling practice relative to all of the steps in developing and applying a model for computing a TMDL. These steps include: problem definition and setting management objectives; data synthesis for use in modeling; model selection; model calibration and, if possible confirmation; model application; iterative modeling; and model post-audit. Since mathematical modeling of aquatic systems is not an exact science, it is essential that these steps be fully transparent to all TMDL stakeholders through comprehensive documentation of the entire process, including specification of all inputs and assumptions. The overriding consideration is that data richness and quality governs the level of model complexity that can be applied to a given system. The model should never be more complex than the data allow. Although the appropriate level of model complexity is difficult to quantify and generally requires experienced professional judgment, it is always desirable to begin with a simple (“back-of-theenvelope”) model and increase complexity only as the data, and other project constraints, allow and the problem definition (water quality endpoints and tolerable uncertainty) demand. Simple models can provide some very insightful diagnostic understanding of the system. Also, in applying a model, one should always attempt to quantify the uncertainty in predictions. In general, quantifying uncertainty is easier with simple models, which is another reason to begin with a simple framework.

Document Type: Research Article

DOI: http://dx.doi.org/10.2175/193864702785071949

Publication date: January 1, 2002

More about this publication?
  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

    WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.
  • Subscribe to this Title
  • Membership Information
  • About WEF Proceedings
  • WEFTEC Conference Information
  • ingentaconnect is not responsible for the content or availability of external websites
wef/wefproc/2002/00002002/00000008/art00002
dcterms_title,dcterms_description,pub_keyword
6
5
20
40
5

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
X
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more