During the summer, our Director of Operations has visited a lot of SuDS devices across the UK. It is always a treat to see SuDS schemes that have been in place for a few years, to see how they are getting along. But Jo has noticed something new sprouting up in these SuDS devices – rat-bait boxes. At Rugby Services and at a site near Victoria station in London, Jo has seen rat-bait boxes in the SuDS devices, tucked in the corners. And at Firs Farm Wetland and Sheffield Grey to Green, she has been lucky enough (?) to see the rats themselves, scuttling about looking for food.
The jury is out on whether this is anything to worry about. After all, one of the functions of SuDS is to attract wildlife and I suppose we should embrace all wildlife, even if they are not very popular! But we need to be careful that this doesn’t become an excuse that clients and designers can use to reduce the amount of SuDS devices that they include on any development. We will face tough times encouraging people to include SuDS as the drive for building intensifies, so we need to be careful to protect the public image of SuDS.
There are steps that designers can take to reduce the risk of rats moving in. Higher curbs can help, and narrow inlets and outlets will reduce accessibility. Having grids over overflows prevents access between the SuDS and the river/sewer, and careful planting can make nesting less desirable. But at the end of the day, there are rats in our cities anyway, so it is likely that the SuDS devices don’t make their numbers any worse.
Good maintenance and frequent litter-picking is essential for SuDS anyway, and this is just another reason to make sure that maintenance is delivered as planned, and for the entire design-life of the scheme.
