There's a paragraph from Helen Moffett that says it best:
"Wait, you kept huge bodies of water in your backyards just so you could swim in them for a few months of the year? You peed in drinking water? You showered or bathed every day? You had bedrooms with bathrooms attached? What do you mean, architects were allowed to design houses where gutters just carried water away into the ground? You had garages for your cars, but no water tanks? Were you people completely crazy? "
This is from Helen Moffett's excellent book, "101 Water Wise Ways". Here, the author is imagining how our grandchildren will talk about us in times of drought in the future.
Although the book is written from a Cape Town perspective with an impending Day Zero (when the potable water supply runs out!), it is something I return to read each Spring/Summer here in the North-West UK when our own droughts extend until our waterbutts run dry.
As I write this, most of the country has experienced 6 weeks of drought followed by thunderstorms (we, in the north-west near Chester and Liverpool were lucky enough to enough to get a weekend of thunderstorms and enough rainfall to replenish our stocks a couple of weeks earlier).
Drought and flood risk are two sides of the same coin, you may have seen Robert Thompson's example circulating LinkedIn of the cup of water being placed on wet, normal and desiccated grass lawn and noting how dry soils do not allow for easy filtration.
Anyone who has a garden or a house plant could tell you the same, that after several weeks of neglect, trying to water that plant from above leads to erosion, with water spilling out over the edge of the pot and taking some of your dry soil with it.
It makes sense not to wee into drinkable water only for it to get sent away to the foul sewer again. For this reason, "re-use" is technically the first option in the drainage hierarchy.
On a previous blog post, I mentioned infiltration was the first option because greywater or even rainwater recycling is expensive, disruptive and is still not a primary outfall solution (what happens if the site users go on holiday for a month?) so it's often ruled out at the beginning of a scheme. However, for commercial/public site uses such as schools, sports facilities, office buildings, warehouses, factories etc., the benefits of rainwater harvesting for non-potable uses such as toilet flushing, vehicle washing, landscape maintenance and so on will far outweigh the cost and disruption of installation.
Curious? Experiment with temporarily turning off the water supply to your toilet cistern and see how much "mostly clean" greywater you can collect from handwashing, dish-rinsing, bath pailing, showering and so on. You might be surprised.
For more detailed tips, definitely check out 101 Water Wise Ways by Helen Moffett. I learn something new with each re-read.
For flood risk and drainage strategy enquiries (including drought resilience strategies), please Get in Touch.
