Rain Gardens Spark Imagination

Recently, I had the opportunity to connect with children from a local elementary school.  The teacher of my daughter’s grade 1 class invited her students to ask their parents if they would come in to school to talk about what they do all day – about what they do for work.  I was asked by my daughter to participate.  As I began imagining how this talk would unfold, it initially did not seem all that threatening, until I started to imagine a room full of bored, uninterested children throwing things around the classroom and generally wreaking havoc – with me as the target.

After some more rational thought, and sensing an opportunity to influence some young minds, I set about drawing up plans for a small, portable rain garden.  The rain garden was intended to be a tool that I would bring with me to engage the children in some interactive learning.  Through some trial and error, the experimental device ended up consisting of a small ( approx. 10 gallon) glass aquarium, divided in half lengthwise with plexiglass fastened in place with a silicon seal.  1/2 of the aquarium surface was capped with more plexiglass and painted black to emulate a road surface.  The other half was planted with typical rain garden plants (mostly Juncus spp.).  Both sides were fitted with drains – the ‘road’ side with a catch basin that led to a piped outlet, and the rain garden side with a perforated underdrain.  The plants in the rain garden side were allowed to grow on for a month, so roots were clearly visible in the growing medium along the glass.  Worm compost was mixed with sand for the growing medium, and in the end this proved most interesting as worm tunnels could be seen all through the soil matrix up against the glass.

Then came the fun part – the actual unveiling of the rain garden/road contraption with a class full of 6-year-olds.  First, 6 children were asked to come forward as volunteers and all of them were given spray bottles and told to ‘make it rain’!  Two containers were placed at each of the drain outlets to catch any ‘runoff’ from the apparatus as a result of the ‘rain’.  Then, while it was raining, a number of additional children were asked to volunteer as ‘polluters’ (everyone was engaged and excited by this point – the challenge here was controlling enthusiasm).  The polluters were given sand, rubber bits, cocoa powder (imitation chemical pollutants – in a container labeled ‘poison’), vegetable oil and a BBQ basting brush.  Polluters were given instructions to release equal amounts of their pollutants on both sides of the contraption.  The BBQ brush was described as a street cleaner, and it was simply used to brush the pollutants into the catch basin on the road side.

What happened next was just plain fun.  Water came pouring out of the pipe leading from the catch basin on the road side of the apparatus almost immediately – as expected.  It carried with it all of the ‘pollution’ from the polluters.  Nothing emerged from the rain garden side.  After some time of simulating rain (and complaints of tired spray bottle trigger fingers), more drastic measures were required to complete the demonstration.  A whole bottle of ‘rain’ was dumped on the rain garden.  Still nothing emerged from the drain.  Two more bottles, about a gallon of water in total, was dumped on the rain garden.  Finally, a slow trickle of clear water emerged from the pipe draining the rain garden side of the apparatus.  Success!

The teaching moments and learning opportunities from this demonstration were quite varied, and enjoyable.  Questions from the children were probing, complex and insightful – this remember from 6-year-olds.  Connections were made to the importance of washing cars on the grass instead of the driveway, to the susceptibility of the natural habitat of the small salmon that they had hatched from eggs in the classroom only days before, and to the connection between road runoff and water quality at local beaches.  The same presentation was given to a grade 3 class (8-year-olds) on the same day with similar results.

Although I had seen rain garden demonstrations in the past at workshops and conferences, the importance of the real-time, side-by-side comparison that this demonstration apparatus afforded was certainly helpful – not to mention fun – in communicating with children.  I suspect it would also begin to stimulate questions and address the concerns of a more ‘mature’ and skeptical audience – food for thought!

Posted by: Paul de Greeff.