Regulating urban diffuse pollution

Written By: Independent environmental consultant

“The problem is, we aren’t able to regulate diffuse sources” is occasionally heard from speakers at conferences or in discussions with water industry colleagues.  Whilst that may be true, it is not the same as stating that diffuse sources cannot be regulated.

But the belief is a problem.  Nearly forty years ago, The Control of Pollution Act, 1974 (COPA) provided for control of surface water drainage (from highways for example) and also included provisions that could establish regulations to prevent pollution from the storage and handling of oil and chemicals.  Those regulatory options, provided for in that far-sighted legislation, were not used or brought into force for many years however.

The problem then was a lack of awareness amongst regulators or NGOs of the need to regulate surface water drainage (they were still faced with serious pollution problems from process effluents from industry and municipal sewage for example), together with a reluctance by government in a recession to bring in storage regulations that might be a burden on industry.   No change there then.

Whilst oil regulations were drafted from 1984 onwards, (and finally brought in under subsequent legislation), equivalent chemical regulations remained an aspiration.  The only diffuse source areas where there was significant regulatory activity (involving discharge limits and monitoring) was for industrial estates, where collective impacts of large areas of impervious surfaces with a wide range of industrial and commercial activities, were well recognised by regulators from the 1970s onwards, and many surface water discharges were consented (licenced).

But what about individual sources on a surface water network?   There has been a belief that individual discharges must be licenced and sampled, under an often expensive monitoring and reporting regime, or not controlled at all.  If resources are stretched controlling major point source discharges, how will the agencies be able to extend coverage massively to regulate many times those numbers of discharges if they have to regulate diffuse sources?

The answer, of course, is a different type of pollution requires a different type of regulation.  One of the reasons why it is useful to have the phenomenon of diffuse pollution conceptualised and defined, is to provide a rational basis for the consequent development of appropriate regulatory regimes.  The often quoted “individually minor, but collectively significant at a catchment scale” characteristic is the key to the regulatory regime needed.  For often individually minor sources, requiring individual licences and monitoring is clearly an inappropriate approach.  In Scotland the Water Environment and Water Services Act 2003 (WEWS) allowed for provisions under the CAR regulations to have general binding rules (GBRs), and diffuse pollution from the built environment has been regulated in Scotland in that way since 2006.

For diffuse pollution GBRs, the simplest analogy is a bald tyre: a minimum tread depth is a statutory requirement, but each tyre doesn’t have to be registered with the police by the car owner for compliance.  Although very detailed and prescriptive, and from an earlier generation of regulations, the oil storage regulations are in effect also GBRs:  it is the law to comply, but generally a licence is not required.

In Scotland since 2006 (modified 2007) GBR101 controls discharges of surface water run-off from the built environment (construction sites, buildings, roads, yards and any other built-up areas).  Rules under GBR 10 include:

“a) If the surface water run-off is from areas constructed after 1 April 2007, the site must be drained by a Sustainable Urban Drainage System (SUDS)….” ….and…

“e) The discharge must not contain any water run-off from any of the following areas constructed after 1 April 2007:

• fuel delivery areas and areas where vehicles, plant and equipment are refuelled;

• vehicle loading or unloading bays where potentially polluting matter is handled;

• oil and chemical storage, handling and delivery areas.”

Note how, for example, GBR 10e) delivers chemical storage regulations in effect in one sentence… how good is that for better regulation?  All the difficulties in trying to apply the detailed prescriptive approach used in developing the oil regulations are avoided by simply leaving it up to the particular industry to select an appropriate means to comply.  Within a few months of the GBRs being published, an architect telephoned SEPA to ask about the GBR, and concluded that if a canopy was put over the loading bay to exclude rain, and the area beneath drained to a sump that would comply.  Regulatory aim achieved.

Industries handling volatile chemicals would need different provisions to those appropriate for water miscible acid or caustic liquids, or foods, etc, but they know what’s appropriate, and the GBR is clear.  The establishment of SUDS technology in Scotland in 1996, ensured recognition of the need to protect amenity interests and functionality within the surface water system itself, when the GBRs were drafted ten years later.  Therefore GBR11 controls discharges into a surface water drainage system, with provisions to exclude sewage and trade effluents, and any matter liable to block or otherwise impair functionality.

The original GBR drafts were even simpler, and there is a great opportunity for Defra to improve upon the Scottish legislation in developing its regulatory regime for England to deliver the requirements of the Water Framework Directive in England.

What is missing now is an appropriate enforcement regime to accompany the appropriate regulations.  In Scotland consideration has been given for several years to a partnership approach with local authorities and the water utility.  The local authorities already use fixed penalties for minor public offences such as littering and dog fouling (diffuse sources) – and have inspectors on the streets (e.g. Glasgow and Edinburgh have environment wardens).  Can Defra follow up with a tidy, minimal best practice regulatory regime to complement the surface water management planning that seeks to encourage use of SuDS?  Or will SEPA and partners in Scotland get there first once again.   Time will tell.





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