5 Preventive measures – silage and slurry storage

14.25 Diffuse water pollution is a more difficult problem to regulate and the emphasis in the legislation has been on preventive measures – to require more adequate storage facilities for farm waste, thus reducing the likelihood of escape of pollutants (such as silage or slurry effluent) into watercourses, and to reduce the eutrophication of water supplies by the leeching of nitrates and other fertilisers applied to the land.

14.26 The precautionary regulations as amended are now consolidated in the Water Resources (Control of Pollution) (Silage Slurry and Agricultural Fuel Oil) (England) Regulations 2010.⁶³ The 2010 Regulations updated the standards for the design and construction of silos and silage storage facilities in accordance with the latest British Standard Institution standards.

(a)Making and storage of silage

14.27 The 2010 Regulations make it an offence⁶⁴ to have custody or control of any crop that is being made into silage unless it is either:

•kept in a silo that complies with the design and constriction specifications in the regulations. Schedule 1 lays down detailed rules as to the siting and construction of silos, by reference to British Standards Institution requirements eg BS5502 (the standards for the construction of buildings and structures for agriculture); or

•compressed into bales which are wrapped and sealed in impermeable membranes (or are enclosed in impermeable bags) and are stored at least 10 metres from any inland fresh waters or coastal waters which effluent escaping from the bales could enter. It is also an offence to remove or open the wrapping on silage bales unless it is done at least 10 metres from any inland freshwater or coastal waters which effluent could enter as a result;⁶⁵ or

•the crop is being made into field silage.⁶⁶ In this case, if the crop is being made into field silage which is being stored on open land, the Environment Agency must be given 14 days notice of the place where the silage is to be made or stored, and it must be stored not less than 10 metres from any inland freshwater or coastal waters. It must, furthermore, be stored at least 50 metres from any protected water supply source ie any water source from which abstraction is licensed, or (in the case of unlicensed abstraction) one of which the location was known to the person making the silage, before the making of the silage began or before it was stored on the land in question.⁶⁷

14.28 Where a silo is used solely to store silage made elsewhere, the Environment Agency can, by notice, relax the requirements outlined above. They can only do so, however, if they are satisfied that there is no significant risk of pollution of controlled waters from the use of the silo. They can impose conditions when giving notice to relax the storage requirements.⁶⁸ The statutory storage requirements (above) do not apply to silage that is stored temporarily in a container, trailer or vehicle in connection with its transport about the farm or elsewhere.⁶⁹

(b)Storage of slurry

14.29 Slurry must be stored in a slurry storage system that complies with the requirements of Sch 2 to the regulations.⁷⁰ The latter applies detailed rules for the standard and siting of slurry storage tanks and reception pits eg by reference to BS 5502 (code of practice on buildings and structures for agriculture).⁷¹ The only exceptions where these requirements do not apply are

•where the storage facility is an exempt structure (below) or

•where the slurry is stored temporarily in a tanker that is used for transporting slurry on roads on or about the farm.⁷²

(c)Storage of fuel oil

14.30 It is an offence to have custody or control of fuel oil on a farm unless it is stored in one of the following ways:⁷³

•in a fuel storage tank within a fuel storage area which complies with the requirements of Sch 3 to the 2010 regulations. The latter require the storage area to be surrounded by a protective bund that meets detailed criteria laid down in Sch 3; or

•in drums within such a storage area; or

•temporarily in a tanker used for transporting fuel oil on roads or about the farm; or

•in an underground fuel storage tank.

14.31 These requirements do not apply if the total quantity of fuel stored on the farm does not exceed 1500 litres.⁷⁴

(d)Exemption for old installations

14.32 The 2010 regulations impose considerable obligations on farmers to install appropriate storage facilities to lower the risk of water pollution. They are not retrospective, however, and provision is made to exempt storage facilities in use before the original 1991 regulations came into force on 1 March 1991. A silo, slurry store, or fuel storage tank is an exempt structure if it was used before 1 March 1991 for the purpose of making silage, storing slurry or, as the case may be, storing fuel oil on the farm. The exemption from the 1991 regulations also applies if the facility was not used before that date, but was constructed before 1 March 1991 for that use.⁷⁵

14.33 The exemption from the standards in the 1991 regulations will be lost, however, if the structure or facility is substantially enlarged, or substantially reconstructed, at any time.⁷⁶ Similarly, exemption will be lost if the Environment Agency serve notice requiring the farmer to carry out preventative works because of a perceived pollution risk, and the notice is not complied with in the time laid down for compliance by the Agency in the notice.

(e)Notice requiring works of pollution prevention

14.34 The Environment Agency have power⁷⁷ to serve notice on any person having custody or control of a relevant substance requiring him to carry out works or take precautions or other steps, which in their opinion are necessary to reduce to a minimum any significant risk of water pollution. The notice must specify the works, precautions or other steps that the Agency is requiring the recipient to carry out, and specify a time period within which it is to be complied with. This must be at least 28 days, and must be a period that is reasonable in all the circumstances. Once a notice has been served, the Agency’s power to vary or alter it without the recipients consent is circumscribed. They can withdraw the notice, or extend the period allowed for compliance with its terms, but they cannot modify the requirements of the notice without the consent of the person on whom the notice was served. The Regulations provide an appeal mechanism under which a person served with a notice to do pollution prevention works can appeal against the notice to the secretary of state.⁷⁸