The Water Resources (Control of Agricultural Pollution) (Wales) Regulations 2021

Regulation 24

SCHEDULE 5 Requirements for silos

1.  The requirement to be satisfied in relation to a silo is that it complies with the following provisions of this Schedule.

2.  The base of the silo must—

(a) extend beyond any walls of the silo,

(b) be provided at its perimeter with channels designed and constructed so as to collect any silage effluent that escapes from the silo, and

(c) have adequate provision for the drainage of that effluent from those channels to an effluent tank through a channel or pipe.

3.  The capacity of the effluent tank must not be less than—

(a) in the case of a silo with a capacity of less than 1,500 cubic metres, 20 litres for each cubic metre of silo capacity, and

(b) in the case of a silo with a capacity of 1,500 cubic metres or more, 30 cubic metres plus 6.7 litres for each cubic metre of silo capacity in excess of 1,500 cubic metres.

4.—(1) The base of the silo must be—

(a) designed in accordance with the code of practice for design of concrete structures for retaining aqueous liquids published by the British Standards Institution and numbered BS 8007: 1987(1), or

(b) constructed using appropriate hot-rolled asphalt in accordance with the code of practice for selection and use of construction materials published by the British Standards Institution and numbered BS 5502: Part 21: 1990(2).

(2) The base of the silo, the base and walls of its effluent tank and channels and walls of any pipes must be impermeable.

5.  The base and walls of the silo, its effluent tank and channels and the walls of any pipes must, so far as reasonably practicable, be resistant to attack by silage effluent.

6.  No part of the silo, its effluent tank or channels or any pipes may be situated within 10 metres of any inland freshwaters or coastal waters into which silage effluent could enter if it were to escape.

7.  If the silo has retaining walls—

(a) the retaining walls must be capable of withstanding minimum wall loadings calculated on the assumptions and in the manner indicated by paragraph 15.6 of the code of practice on buildings and structures for agriculture published by the British Standards Institution and numbered BS 5502: Part 22: 2003(3),

(b) the silo must at no time be loaded to a depth exceeding the maximum depth consistent with the design assumption made in respect of the loadings of the retaining walls, and

(c) notices must be displayed on the retaining walls in accordance with paragraph 18 of that code of practice.

8.  Subject to paragraph 9, the silo, its effluent tank and channels and any pipes must be designed and constructed so that with proper maintenance they are likely to continue to satisfy the requirements of paragraphs 2 to 5 and, if applicable, paragraph 7(a) for at least 20 years.

9.  If any part of an effluent tank is below ground level, the tank must be designed and constructed so that it is likely to continue to satisfy the requirements of paragraphs 4 and 5 for at least 20 years without maintenance.

(1)

Publication date: 30 October 1987. ISBN 0-580-16134-X.

(2)

Publication date: 31 December 1990. ISBN 0-580-18348-3.

(3)

Publication date: 10 June 2003. ISBN 0-580-38654-6.