Ensuring the maintenance of sustainable drainage systems (SUDS) is a critical problem (NCE 8 February). Alongside the legal difculties of adoption by the drainage authority, there are practical difculties of recognising the need for maintenance work and carrying it out.
Traditional piped systems are largely self-cleansing. If they become blocked, the resultant local ooding is obvious and prompts action.
In contrast, the clogging of soakaways and permeable surfaces is likely to result in saturated soil and water oozing remotely from the cause. Even if the problem is recognised and the cause diagnosed, remedial treatment may not be straightforward or cheap.
I am also concerned about planners' lack of understanding about drainage. It is all too common for potential developers to put on the planning application form that surface water drainage will be to a soakaway.
This atises the policy for SUDS, but how many planning ofcers ask for porosity tests and calculations of the appropriate size of soakaway, ask for the specication of the soakaway and check that it is feasible for the site, or consider the cumulative effects of soakaways in areas where the ground becomes saturated in winter conditions.
And are they prepared to refuse planning permission if they are not satised with the drainage proposals?
These questions need to be addressed.
John E Acton, The Jays, 1B New Street, Chareld, Wotton-under-Edge, Gloucestershire, GL12 8ES