I've always had this nagging feeling that there was something amiss in the world of SUDS. I thinks the whole acronym thing is a clue here. SUDS stands for Sustainable Urban Drainage Systems. I have even seen it written as Sustainable (Urban) Drainage Systems. It's that Urban bit that stands out. Why in particular should a drainage system be Urban, rather than rural or suburban?
And if it is urban, should SUDS be restricted to urban areas? Are SUDS necessarily a green solution to the problem of surface water run-off? Or just a good solution for densely packed areas where flooding might be a problem?
Maybe it's that word Sustainable at work again, but SUDS have somehow been incorporated into the Code for Sustainable Homes as a must-have feature. You might think that a good old fashioned soakaway would be just the ticket but the Code calls for something a little more sophisticated than this. It requires you to provide robust hydraulic design calculations referred to in key guidance documents such as The SuDS manual (CIRIA C697, 2007) and Preliminary rainfall runoff management for developments (EA/DEFRA, 2007).
Blimey. Sounds like you need an expert! Indeed you do. Suitable professionals may be found in a variety of disciplines, such as engineering, landscape design or hydrology.
Now experts have a habit of recommending complicated solutions and the Code experts have cooked up a real beauty here. It now seems that if your site doesn't pass the porosity test for normal soakaways, then the Code requires that you fit a rainwater harvesting system to act as a holding tank for surface water run-off. Now rainwater harvesting systems are all fine and dandy (or at least many people think they are) but not even their biggest fans think that they are to be confused with SUDS, as their purpose is quite different.
A SUD system is basically just an engineered-but-still-dumb soakaway, whereas as rainwater harvesting system needs a good deal of management and lots of bits added onto it in order to function correctly. As well as being expensive to install (maybe £3,000 per property), they also have to be maintained.
But the way it stands, if you are on a site where conventional soakaways will not work then, in order to get to Code Level 3, you will have to fit Rainwater Harvesting. Not to deliver low levels of water use within the household (for which it is designed) but to act as a SUDS-compliant soakaway (for which it isn't). And that would seem to include sites well away from urban areas.
Have a look at this video of some of the recent Queensland flooding and ask yourself how your rainwater harvesting system would have coped. Or, for that matter, just about any SUDS system you could dream up.