Creative Redirection Of Roof Runoff
By Anno Torr
Capturing rainwater from a house roof is an imperative these days, and, while substantial tanks the most common container used especially to collect and store large volumes of rainfall directed through a single downpipe, they don't suit every homeowner's budget.
So, why not get creative in the way you manage even a single downpipe, like this design that simultaneously solves the problem of filling swimming pools while water restrictions are in place. Here, an attractive rocky stream takes rainwater directly from rooftop to pool. As the house sits on a level above the pool, it becomes a simple gravity exercise. Rocks set in concrete provide a tiered gully down which the water tumbles, with sides shaped gently towards the centre and a sprinkling of river stones helping to guide the flow. Splash provides moisture to nearby plants as does overflow during peak flows from prolonged or heavy rainfall.
Build in a few shallow pools along a meandering route downwards, and they’re sure to entice local birds and frogs (hopefully this arrangement sits below the kitchen and not a bedroom). This tumultuous course helps to clean and oxygenate the water as it flows, much like a little rocky mountain stream, and, with such a short distance between the pool and house, it is easy to install a reticulation pump to recycle the water continuously. While most of us won’t have the same set-up, it is possible to use the general idea in a variety of different situations.
For the steep slope among the rocks choose plants for hot sun and shallow dry soils, like Aristida junciformis and Melinis nerviglumis grasses mixed with ground aloes and the clambering Aloe tenuoir. Tulbaghia violacea, Chlorophytum saundersiae and Dietes bicolor add strappy leaves to this grassy design. For areas damp from splash and overflow, try shallow-rooting Senecio speciosus, Aristea ecklonii, and Hypoxis species to bring in seasonal flowers, and the water-loving Cyperus albostriatus, though it seems to do well enough in your average garden soil.