One of my favorite bloggers, Barry Fagan PE/PLS, CPESC, leads Alabama DOT’s Environmental Program, as well as being ALDOT’s unofficial Chief Environmental Evangelist. His blogs are always entertaining, thoughtful and well reasoned. He’s given me permission to share them with you occasionally, and I believe Barry’s blog this week , offers a particularly useful insight….
“The Candle Problem” was devised by psychologist Karl Duncker in the 1930′s. In the problem a table is placed against a wall. The participant is given materials: a candle, a box of tacks, and a book of matches. The goal is to attach the candle to the wall in a manner that prevents wax from falling on the table. Take a moment to think about your solution.
Most unsuccessful attempts involved trying to stick the candle to the wall with wax and/or tacks. The approach simply does not work. But after a few minutes, most people discover the solution – the box holding the tacks becomes a candle-holder that can easily be attached to the wall.
Dunker decided that the problem was that participants became “fixated” on the box only serving as a container for tacks. Follow up experiments by Dunker and others showed that when the box and tacks were separated, people were much more likely to see the box as one of the materials available to solve the problem.
Stormwater professionals can also become fixated on function.
With available space coming at a premium in a transportation setting or commercial development, we still refuse to see roadside ditches as being anything other than open-channel conveyances. We see mandatory tree wells and traffic islands as nothing more than surface plant containers. We see rooftop and parking lot runoff as nothing more than a by-product that must be “managed” or disposed of regardless of cost. We assumed that level spreaders and detention basins are only for reducing the peak discharge and energy of runoff. In construction, sediment basins are only for treating turbidity, vegetated buffers are only for trapping sediment. Sidewalks are only for walking.
We are often correct when we say we don’t have enough room or budget to adequately treat stormwater, when added to all of the other functions our project must serve. But what if somehow we could combine functions, or create elements of infrastructure that are multi-use? Permeable sidewalks could reduce runoff; deep tillage under roadside ditches and slopes could promote pollutant capture; sediment basin bottoms could be managed to infiltrate turbid water; level spreaders could serve a construction function as well as post construction; detained runoff could buffer rates of discharge and sustain landscaping. That is the very definition of green infrastructure.
Green infrastructure created solely for the purpose of creating green infrastructure isn’t green infrastructure.
An interesting fact – when tested, 5-year-old children show no signs of functional fixedness. For some reason, we develop boundaries and our ideas become limited as we “grow up.” A career involving dirt and water has always been very close to child’s play for me. The challenge of finding new ways to utilize old elements in our projects can also be fun – almost as satisfying as playing with Legos.
But, if we must insist on being adults and calling it work, please remember that our clients, employers, customers, taxpayers, and society are all counting on us to create better solutions. Whether we have fun or not is really not their concern.
Daniel Pink’s book Drive led me to Dunker’s work and application of the concept of functional fixedness.
Think about this conversation in the context of the ubiquitous municipal landscape ordinances which require a certain number of trees and landscape in new developments. Most often those requirements are met by landscape islands or perimeter beds that are raised and bounded by curbs. Because they receive only the rainfall that lands on them, most are irrigated. This is the function of landscape and tree canopy being met. Likewise, the function of drainage, conveyance and water quality are all met by their own systems. The rules in most places require exactly this approach. This is the quintessential functional fixation.
By removing the continuous curb, lowering the landscape bed and utilizing it as a bioretention system, a single system can now serve numerous functions (landscape, trees, drainage, conveyance, water quality, etc.)…and if well designed, can coincidentally reduce the cost of the project (eliminating catch basins, inlets, much of the pipe used to connect them and reducing the size of the pipe that remains).
The cost of allowing ourselves to continue sticking the candle to the wall with tacks and wax is far too high.
I can imagine a presentation that starts with “The Candle Problem” as a device to begin a conversation about multi-functional landscape and dual use stormwater facilities of many kinds.
