WATER HARVESTING EARTHWORKS “DESIGN TO REALITY”. PART 1
So, you have been contacted by a client and you’ve discussed the client’s brief. You’ve started to look at the contour map, aerial images, whatever data you can find on the site. And with the client brief in mind, always remembering WATER IS LIFE, you set to the task of patterning the landscape using functional forms.
You start to look at what’s the most economical way to hold water in the landscape, move water around the landscape passively and make it perform as many duties as possible before it leaves the site.
Next is to develop the mainframe design theme. A big part of this is looking for high water storage sites. So we take the approach of looking at the contour map to take into account where the highest possible spot is, where water can safely be stored on the site in dams, (always considering how much catchment area is above the potential dam site or if there are any hard-surface run-off areas above the dam site).
Reader’s will understand catchment area, but hard surface run-off areas aren’t so well utilised and it’s just a bit of pattern recognition to identify when you look at a new site.
Identifying hard surface run off areas
Hard surface run-off areas with a bit of design thinking, can brought into our water harvesting systems. At times it doesrequire good observation skills to identify them, but there are generally clues for the observer.
There are many examples of hard surface run-off areas, sometimes called ‘hard-ware’. Your roof, a road, any compacted surface or a rock outcrop are all examples of ‘hard-ware’.
Gravel roads run off 85% of the water that hits the surface. Concrete areas 100% minus whatever evaporates, and your roof 100%.
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