7 DWR CYMRU CYFYNGEDIG
Introduction
Dwr Cymru Cyfyngedig supplies on average about 1,000 Ml/d water to around 2.8 million consumers in an area covering most of Wales and parts of Hereford and Worcester and Gloucestershire. Approximately 59% of the Company’s water supplies come from impounding reservoirs, 35 % from river abstractions and 6% from boreholes and springs. The Company has 109 treatment works, and distributes water through 24,900 km of pipes and 564 service reservoirs to 183 water supply zones. In addition there is a small bulk supply from Severn Trent Water Limited.
Overall water quality
At water treatment works and service reservoirs and in water supply zones, the Company carried out a total of 159,913 determinations in 2000. Of these, 99.75% demonstrated compliance with the relevant PCV, but 397 showed a contravention to have occurred.
Coliforms were not detected at 103 (94%) of the Company's 109 water treatment works. At 563 (>99%) of the Company's 564 service reservoirs, coliforms were absent from at least 95% of samples. Of the Company's 183 water supply zones in 2000, 181 (98.91%) complied fully with the relevant water quality standards or had breaches of the standards which were either trivial or were fully covered by undertakings. In the other two (1.09%) of the zones, some breaches could result in enforcement action.
Microbiological quality of water leaving treatment works
The Company complied with the sampling frequencies required by regulation 17 at all but one of its treatment works in 2000. The shortfall at the works is regarded as trivial.
Table 7.1 shows the Company's performance in 2000, with data for 1999 and 1998 for comparison. Differences from 1999 in the number of treatment works, and samples from treatment works, in which coliforms or faecal coliforms were detected are not considered significant.
All contraventions of the standards at works are considered trivial or unlikely to recur.
Microbiological quality of water in service reservoirs
The Company complied with the sampling frequencies required by regulation 18 at 552 of its 564 service reservoirs in 2000. Shortfalls at the other 12 are regarded as unlikely to recur due to exceptional weather conditions preventing the samples being taken.
Table 7.2 shows the Company's performance in 2000, with data for 1999 and 1998 for comparison. Differences in the last three years in the number of service reservoirs, and samples from service reservoirs, in which coliforms or faecal coliforms were detected, are not considered significant.
All other contraventions of the standards at service reservoirs are considered trivial or unlikely to recur because remedial action had already been taken.
Water quality in water supply zones
The Company failed to comply with the required sampling frequencies for a number of parameters in several zones. All contraventions of the standards in zones are considered trivial or unlikely to recur.
Table 7.3 shows the Company's performance in 2000, with data for 1999 and 1998 for comparison. Differences over the last three years are not considered statistically significant.
Enforcement action is being considered in respect of some contraventions of standards, as shown in tables 7.3 and 7.4. All other contraventions of the standards in zones are considered trivial or unlikely to recur, or a covered by undertakings.
Inspection
Follow-up of recommendations from the 1999 annual inspection Mr A Hallas, Inspector, followed up on the recommendations from the 1999 annual inspection. Mr Hallas concluded that:
the Company has made appropriate and positive response to the recommendations made in the 1999 report.
Inspection of work being carried out on the distribution system In June 2000, Mrs C Malhotra carried out an audit of work being carried out on the distribution system. Mrs Malhotra concluded that:
the contractor working on behalf of Dwr Cymru Cyf. was carrying out work in accordance with health and hygiene practices.
All excavations inspected were in exemplary condition.
Inspection of tankering activities
In August 2000, Mrs C Malhotra carried out an audit of tankering activities. Mrs Malhotra concluded that:
the overall set up for the tankering operation was good and in general hygiene practices were being observed.
Audit trails of five samples
Mr R M Walls, Consultant, working under the direction of Mr W M Waite, Principal Inspector carried out audit trails on five samples chosen at random. Based on Mr Walls report Mr Waite concluded that:
The sampling and analytical arrangements are generally satisfactory but improvement should be made at a number of points. The temperature of water in distribution is only recorded to the nearest whole degree, which is inadequate to meet the accuracy of ±0.5° in the Guidance Document. The analytical results have appeared on the Public Record in time, although several parameters are expressed in the wrong units.
Audit of plumbosolvency treatment and control programmes of work
In November 2000, Consultants WS Atkins, represented by Mr S Ntifo, working under the direction of Mr P Halton, Inspector, carried out an audit of the Company as part of the Inspectorate’s work in agreeing with water companies’ their programmes of works to secure compliance with the new lead standards. Based on Mr Ntifo’s report, Mr Halton concluded that:
the Company’s process of sites/scheme selection for plumbosolvency treatment and/or optimisation measures is sound;
the integrity of the data submitted to the Inspectorate and used for assessing plumbosolvency needs is inadequate, as noted in the relevant sections of the report;
of the schemes audited, irrespective of the discrepancies observed, some of the schemes are justified on water quality reasons for inclusion in the Company’s programme of works for plumbosolvency measures; and
The Company’s proposed steps to be taken and the proposed completion dates are generally sound.
Inspection of Company’s control room
In November 2000, Mrs C Malhotra carried out an audit of control room practices and procedures. Mrs Malhotra concluded that:
Overall, Swansea Control Centre is operating to an excellent standard and maintaining good control of alarm announcements within Dwr Cymru Welsh Water.
Procedures in the main are thorough and stringent with little scope for employees to deviate.
The DWI commends the Company in continuously improving and upgrading the telemetry links with Company assets and outstations to ensure greater efficiency of operations.
Review of procedures for operation and maintenance of the distribution network
In December 2000, Consultants Binnie, Black and Veatch working under the direction of Mr W M Waite, Principal Inspector carried a follow up investigation of the recommendations made during the 1999 audit of the Review of Procedures for Operation and Maintenance of the Distribution Network. Based on their report Mr Waite concluded that:
that to provide an adequate response to that response to recommendations that is considered inadequate, the company extend its procedures to provide the following;
Extend its system to include the routine monitoring of the status of all valves covered by the valve classification system and their markers (System for Classifying, Recording, Marking and Monitoring Valve Status - Recommendation R8.4).
Inspection of distribution system improvement programme progress
In September 2000, Consultants Parkman Ltd, represented by Mr B Jones, working under the direction of Mr P Halton, Inspector, carried out an audit of the Company’s progress with the mains renovation set out in the distribution Undertaking submitted by the Company. Based on Mr Jones’s report Mr Halton concluded that:
the objectives of the undertaking remained valid;
the steps to be taken were defined with adequate precision;
a practicable timetable had been set; and
the Company was likely to meet the target renovation length by the date for completion of the work.
As a result of these inspections, 11 recommendations were conveyed to the Company for formal response. Five suggestions on various matters were also made. The Company is taking action or has already taken action on a all of the recommendations.
Improvement programmes
Four undertakings in respect of improvement programmes accepted by the Secretary of State from the Company were due for full completion or the completion of major steps during 2000 and all of these were completed on schedule.
The ongoing distribution system improvement programmes due for completion in 2010, which have been implemented by the Company, have been progressing satisfactorily.
Incidents
Eleven of the events notified during 2000 by the Company to the Secretary of State under the terms of the Water Undertakers (Information) Direction 1998 were regarded by the Inspectorate as constituting incidents in which drinking water quality demonstrably deteriorated.
Six incidents have been assessed. Three of these incidents involved the supply of discoloured water following work carried out in the distribution system by the Company. These incidents affected consumers in: Deiniolen and Rhyl in April and Merthyr Tydfil in September.
Two incidents were concerned with the detection of Cryptosporidium oocysts, both occurred at Capel Curig Water Treatment Works during August. There was no associated cryptosporidiosis outbreak in the community. One incident was concerned with the detection of Cryptosporidium oocyst like bodies at Garn Dolbenmaen Water Treatment Works in August.
The Company took all reasonable steps to protect consumers during each of the above incidents and has also responded positively to the recommendation made by the Inspectorate. Following the detection of Cryptosporidium oocysts on two occasions at Capel Curig water treatment works, the Inspectorate initiated enforcement action against the Company. The Company has now given a legally binding undertaking to carry out remedial works to prevent any recurrences.
Five incidents remain under consideration. One concernes the detection of Cryptosporidium oocysts at Bretton WTW in May; two involve the supply of discoloured water to Merthyr Tydfil and Alwen WTW supply area in July and November; another involves an adverse taste and odour in the Talybont WTW supply area in October, and the other concerns an illness outbreak in the community that may be associated with water quality.
No other events regarded as constituting incidents came to the attention of the Inspectorate in 2000.
Enforcement action
Table 7.4 summarises enforcement action under consideration for the Company as a result of the Inspectorate's work in, or pertaining to, the calendar year 2000.
table 7.1 Dwr Cymru Cyfyngedig
MICROBIOLOGICAL QUALITY OF WATER LEAVING TREATMENT WORKS2000 1999 1998 Number of water treatment works 109 111 111 Works with no sampling shortfall 103 111 111 COLIFORMS Total number of determinations 12,973 14,647 15,319 - number containing coliforms 7 10 22 - % containing coliforms <0.1 0.1 0.1 Treatment works with coliforms detected 6 8 18 - % of all works 5.6 7 16 FAECAL COLIFORMS Total number of determinations 12,973 14,647 15,319 - number containing faecal coliforms 2 0 5 - % containing faecal coliforms <0.1 0.0 <0.1 Treatment works with faecal coliforms detected 2 0 5 - % of all works 1.8 0 5
table 7.2 Dwr Cymru Cyfyngedig
MICROBIOLOGICAL QUALITY OF WATER IN SERVICE RESERVOIRS2000 1999 1998 Number of service reservoirs 564 572 597 Service reservoirs with no sampling shortfall 552 572 595 COLIFORMS Total number of determinations 29,412 30,461 30,915 - number containing coliforms 66 59 74 - % containing coliforms 0.2 0.2 0.2 Service reservoirs with coliforms detected 56 53 64 Service reservoirs with coliforms detected in more than 5% of samples 1 1 2 - % of all service reservoirs 0.2 0.2 0.3 FAECAL COLIFORMS Total number of determinations 29,410 30,461 30,916 - number containing faecal coliforms 12 17 18 - % containing faecal coliforms <0.1 0.1 0.1 Service reservoirs with faecal coliforms detected 11 15 16 - % of all service reservoirs 2 3 3
table 7.3 Dwr Cymru Cyfyngedig
WATER QUALITY IN SUPPLY ZONESColumns 'CBU' show, for determinations, contraventions covered by undertakings and, for zones, the total number of zones covered by undertakings in 2000. Column 'E' shows the number of zones for which new enforcement action is under consideration as a result of contraventions of the PCV in 2000. Please refer to the Introduction to Part 2 for more detailed explanation of this table. PARAMETER DETERMINATIONS in 2000 ZONES (183 in 2000)* Total Contravening PCV Non-compliant No. % CBU CBU E Number in: 2000 2000 1999 1998 Coliforms 8,938 27 0.3 0 0 0 0 0 1 Faecal coliforms 8,937 3 <0.1 0 0 0 3 2 4 Colour 858 0 0.0 0 0 0 0 0 0 Turbidity 944 0 0.0 0 0 0 0 1 2 Odour 1,228 1 <0.1 0 0 0 1 3 4 Taste 1,029 1 <0.1 0 0 0 1 1 6 Hydrogen ion 1,083 2 0.2 0 0 0 2 3 2 Nitrate 852 0 0.0 0 0 0 0 0 0 Nitrite 1,894 129 6.8 0 0 0 29 30 28 Aluminium 1,048 3 0.3 1 1 0 3 3 4 Iron 2,903 57 2.0 56 36 0 37 37 49 Manganese 1,337 13 1.0 12 7 0 8 8 15 Lead 584 3 0.5 0 0 0 3 3 8 PAH 740 57 7.7 56 23 0 24 33 34 Trihalomethanes 675 6 0.9 4 1 1 2 6 4 Total pesticides 902 0 0.0 0 0 0 0 2 1 Asulam 659 0 0.0 0 0 0 0 0 1 Ammonium 380 0 0.0 0 0 0 0 2 1 2,4-D 724 0 0.0 0 0 0 0 1 2 2,4-DB 724 0 0.0 0 0 0 0 0 1 Carbendazim 494 0 0.0 0 0 0 0 1 0 Linuron 380 0 0.0 0 0 0 0 1 0 Mancozeb 64 0 0.0 0 0 0 0 1 0 MCPA 725 4 0.6 0 0 1 3 1 1 Mecoprop 725 0 0.0 0 0 0 0 1 2 Simazine 379 1 0.3 0 0 0 1 0 0 Other pesticides 16,974 0 0.0 0 0 0 0 0 0 Benzo 3,4 Pyrene 740 2 0.3 0 0 0 1 0 0 Oxidizability 207 0 0.0 0 0 0 0 1 0 Surfactants 191 1 0.5 0 0 0 1 0 0 All others 17,827 0 0.0 0 0 0 0 0 0 TOTAL 75,145 310 0.4 155 - - - - - *184 zones in 1999; 189 zones in 1998.
table 7.4 Dwr Cymru Cyfyngedig
SUMMARY OF ENFORCEMENT ACTION CONSIDERED IN 2000Regulation reason for enforcement Regulation 3(3)(c) Contravention of the standard for iron in one zone. Regulation 3(3)(c) Contravention of the standard for MCPA in one zone. Regulation 3(3)(e) Contravention of the standard for THM in one zone. Regulation 23B(1) Contravention of the Cryptosporidium treatment standard at two treatment works.
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Drinking Water Inspectorate,
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Published 11 July 2001
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