1.—(1) These Regulations may be cited as the Surface Waters (River Ecosystem) (Classification) Regulations 1994 and shall come into force on 10th May 1994.
(2) In these Regulations references to a numbered column are references to the column so numbered in the Schedule to these Regulations.
2.—(1) A system employing the classifications RE1, RE2, RE3, RE4 and RE5 is prescribed as a system of classification applying to inland freshwaters which are relevant rivers or watercourses(1).
(2) The criteria for each of the classifications RE1 to RE5 are that the following requirements are satisfied by a series of samples of water taken and analysed in accordance with regulation 3, that is to say—
(a)the 10 percentile of the saturation of dissolved oxygen shall not be less than the value specified in respect of that classification in column (2);
(b)the 90 percentile of the biochemical oxygen demand shall not exceed the value specified in respect of that classification in column (3);
(c)the 90 percentile of the concentration of total ammonia shall not exceed the value specified in respect of that classification in column (4);
(d)the 95 percentile of the concentration of un-ionised ammonia shall not exceed the value, if any, specified in respect of that classification in column (5);
(e)the 5 percentile of the pH value shall not be less than the lower value, if any, specified in respect of that classification in column (6), and the 95 percentile of the pH value shall not exceed the higher value, if any, so specified;
(f)the 95 percentile of the concentration of dissolved copper shall not exceed the value, if any, which is specified in respect of that classification in column (8) by reference to the hardness of the water as described in column (7); and
(g)the 95 percentile of the concentration of total zinc shall not exceed the value, if any, which is specified in respect of that classification in column (9) by reference to the hardness of the water as described in column (7).
3. The following matters, that is to say—
(a)the frequency, location and methods of sampling;
(b)the samples to be used, or to be disregarded, for the purpose of assessing whether any requirement specified in regulation 2(2) is satisfied;
(c)the requirements for analysis of samples; and
(d)the methods of determining percentile values,
shall be determined by the National Rivers Authority in accordance with the procedures, and by reference to the principles, set out in the document dated 30th March 1994 and entitled “Water Quality Objectives: Procedures used by the National Rivers Authority for the purpose of the Surface Waters (River Ecosystem) (Classification) Regulations 1994”.
Signed by authority of the Secretary of State for the Environment
Robert Atkins
Minister of State,
Department of the Environment
8th April 1994
Signed by Authority of the Secretary of State for Wales
Gwilym Jones
Parliamentary Under Secretary of State, Welsh Office
12th April 1994