Stormwater Treatment Terminology: A Tower of Babel
Simplify and Clarify
“The proliferation of terminology has lead to misperceptions of performance, uncertainty as to applicability of particular treatment systems, and the inconsistent, confusing, and sometimes illogical application of design criteria,” wrote Dr. Gary R. Minton in an article published by Stormwater Magazine in its March/April 2007 issue. The article is titled A Tower of Babel: A Proposed Framework for Treatment Terminology.
Formal, Logical and Simplified Framework
“What is needed is a simplified framework with concurrence on a common name for the same treatment system to which design criteria are applied consistently.”
Dr Minton’s key recommendation is to simplify and clarify. “Let’s not use descriptors that imply a process or expectation of performance that does not exist, like vortex separation. Let’s use descriptors that are as explicit as possible, such as infiltration cell rather than bioretention. Explicit terms convey directly the nature of the unit operation.”
“Let’s not use descriptors whose definition applies so broad as to be meaningless,” stated Dr. Minton. “We need to establish a single name for what is essentially the same unit operation…. Grouping of the variants under a common name will lead to consistent sets of design criteria.”
“We need a formal, logical, and simplified framework akin to what was developed by the great Swedish scientist of the 18th century, Linnaeus, for biological species. His achievement followed several centuries of confusion and overlap of terminology. Hopefully, it won’t take us that long,” Dr. Minton concluded.
To read the complete story in Stormwater Magazine, click on A Tower of Babel.
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.
About Gary Minton:
Dr. Gary Minton has been a leading contributor to the development of design criteria for rainwater/stormwater treatment relevant to the conditions of the Pacific Northwest. He is the author of the textbook Stormwater Treatment.
In October 2007, Dr. Minton was a member of a cross-border panel at a joint Washington State/British Columbia conference held in Seattle. The panel compared an American top-down prescriptive approach versus a Canadian bottom-up educational approach.
To learn more, click on Rainwater Management on Diverging Paths in British Columbia and Washington State?
Simplifying the Terminology for Rainfall Capture in British Columbia
“In British Columbia, the technical language is being progressively simplified so that there will be a clearer public and practitioner understanding of the suite of source control options for capturing rain where it falls,” reports Kim Stephens, Program Coordinator for the Water Sustainability Action Plan for British Columbia.
“The simplification process began with release of Stormwater Planning: A Guidebook for British Columbia in 2002. The next leap forward came with publication of Stormwater Source Control Design Guidelines 2005 – Final Report by Metro Vancouver. These guidelines were developed to complement the Water Balance Model for British Columbia.”
“The 2005 Guidelines simplified the myriad of source control types down to these six categories: absorbent landscapes, infiltration swale system, rain gardens, pervious paving, green roof, and infiltration trench/soakaway.”
Metro Vancouver's Guidelines
“The objective of this project was to reduce information barriers that previously stood in the way of effective implementation of rainwater source controls in the Georgia Basin region of British Columbia,” states Ed von Euw, Senior Engineer with Metro Vancouver Regional Utility Planning.
“Our focus was on the technical details of practices in landscape areas that treat rainwater through plant materials and soils by infiltration, retention, detention and evapotranspiration.”
To learn more, click on Stormwater Management, Low Impact Development, Sustainable Drainage, Green Infrastructure, RAINwater Management…. what is an appropriate term to use?
Rainfall Infiltration and Excess Runoff
“Looking back, the 2005 Guidelines represented a major breakthrough in simplifying practitioner thinking in BC,” reflects Jim Dumont, Engineering Applications Authority for the Inter-Governmental Partnership that developed and maintains the Water Balance Model.
“Five years later, the timing may be right for the next leap forward in order to achieve Gary Minton’s vision for a formal, logical and simplified rainwater management framework.”
“Once one removes the Tower of Babel (as Gary Minton calls it) by going back to basics and examining the physical processes, there are only two processes in play: rainfall infiltration and excess runoff.”
“The key to thinking this way is recognizing that the differentiation is made by their physical operation rather than their visible components.
Going Back to Basics
“The first physical process is a surface change that alters the infiltration into the soil; and the second process deals with the excess rainfall as surface runoff by storing it and then doing something to the volume. This set of process differentiation is built into the Water Balance Model.”
“If we examine absorptive landscapes, porous pavements and even green roofs one realizes that they are all operating by enhancing surface infiltration of rainfall and act in a like manner.”
“On the other hand biofiltration swales, infiltration ponds and even rain gardens receive surface runoff from other areas and store it while infiltration and evapotranspiration occur and when they are full they overflow. These later operate in a similar manner by collecting excess surface runoff and represent the second type of rainfall capture devices,” concludes Jim Dumont.
“Looking ahead, this approach in 'going back to basics' will be a key message in the outreach and continuing education program delivered by the Inter-Governmental Partnership,” states Kim Stephens.
About Jim Dumont:
The Engineering Applications Authority is responsible for developing and/or overseeing development of the hydrology applications and stream health methodologies that enhance the Water Balance Model as a scenario modeling and decision support tool for use at the site, neighbourhood and watershed scales.
To learn more, click on Inter-Provincial Partnership names Jim Dumont as the Engineering Applications Authority for the Water Balance Model.
Posted March 2010