Voodoo Hydrology explained by Andy Reese


Andy reese - voodoo hydrology

Andy Reese, in the July/August 2006 issue of Stormwater Magazine, offered his perspective on urban hydrologic practice. His article is about understanding some of the basics of methods drainage designers have taken for granted for years. The link from the Water Bucket to the Andy Reese article is provided for information purposes that foster and promote a discussion of the technical aspects of hydrology and the analyses used by practitioners. It is not provided to establish standards of practice or to indicate best methodologies to be used in engineering design.

Andy Reese collaborated with Tom Debo of Georgia Tech to co-author the textbook Municipal Stormwater Management. As a principal author of several state and local design manuals and as a past university teacher in hydrology, Reese states in the article that he has been repeatedly reminded of the black box nature of urban stormwater hydrologic design, and the often minimal level of understanding of many designers who are sizing and placing infrastructure within urban neighborhoods and other developments every day. A well-known humourist, Reese wryly notes that:

  • “Urban hydrology, as commonly practiced, is an inexact science at best. Most Andy reese (120p)professional hydrologists would hold their noses at some of the methods commonly used. The reason is that the methods are a number of steps back from our best statistical estimate of reality. Urban hydrology is a compromise between accuracy and data availability. And as Murphy would have it, a densely populated urban setting is the one place a designer would most want to be accurate in flooding predictions, and is also the one place where accuracy is often least possible to attain.”

The article points out some of the methodologies that can be used to obtain any number of “correct” answers. This is the spirit of the article in being provocative, as contrasted with a compilation of current and acceptable state of the practice.


Before STORMWATER, The Journal for Surface Water Quality Professionals, there was no single publication written specifically for  the professional involved with surface water quality issues, protection, projects, and programs. To download a copy of the Andy Reese article, click on this link to Voody Hydrology.


Posted March 2008