2.16. United Kingdom

2.16. United Kingdom

2.16.1. Characteristics of Groundwater

2.16.1.1. England and Wales

The three most important aquifers are the Chalk, the Sherwood Sandstone and the Jurassic Limestones which are consolidated, indurated sedimentary formations with dual porosity. The smaller aquifers have similar characteristics. They are formations in which groundwater flow has varying combinations of matrix and fractured flow components producing complex aquifers. These characteristics make representative sampling difficult. Another aspect is that smaller but important groundwater bodies are situated in consolidated sedimentary aquifers which are often heavily exploited.

 
2.16.2. Structure of the Administrative Organisations Concerning Groundwater Quality

2.16.2.1. England and Wales

The National Rivers Authority (NRA) is the responsible organisation that assesses and manages groundwater quality monitoring required by European and UK legislation. Section 84 of the Water Resources Act 1991 obliges to „monitor the extent of pollution in controlled waters" , including groundwater. Sampling frequencies or determinands are not nearer specified by present legislation, with the exception of the EC Nitrate Directive. Moreover, in a European context, there is an increasing need for all EC member states to be able to provide a comprehensive national picture of the national status of water resources. Due to European and UK legislation other organisations are obliged to monitor water quality too.

• Waster Regulatory Authorities (WRAs) act on the Environmental Protection Act 1991 to ensure the property of local monitoring activities in the fields of the performance and security of landfill sites and the detection of pollution of groundwater from such sources.

• Drinking Water Inspectorates (DWIs) survey the potability within public water supply systems. They evaluate compliance with the EC Drinking Water Directive

• District Council Environmental Health Inspectors act in accordance with their duties under the Private Water Supply Regulations 1991

Samples taken from the organisations are not exceptionally raw water samples and consequently not representative for the groundwater in the referring aquifer.

The primary objectives for the national groundwater quality assessment for the NRA are:

• trend identification of groundwater quality changes caused by natural events or the impact of diffuse pollution sources and changes in the hydraulic regime.

• collect baseline information on groundwater quality in order to detect future impacts

• provide a picture of the three-dimensional distribution of groundwater quality within aquifers

• set up of an early warning system in recharge areas on aquifer outcrops of the impacts of diffuse sources of pollution

• provide information to meet the requirements of the EC Nitrate Directive to identify Nitrate Vulnerable Zones

Furthermore, information on industrial and urban impacts are to be gained; groundwater protection facilities are to be evaluated; contaminated land impact, landfill impact and saline intrusion are to be assessed; groundwater and surface water interaction are to be described, incident impacts are to be assessed and models used for prediction of groundwater quality are to be validated.

2.16.2.2. Scotland

In Scotland the Secretary of State for Scotland has overall responsibility for national water policy in Scotland. The Scottish Environmental Protection Agency(SEPA) has the duty to promote the quality of all controlled waters. SEPA undertakes the monitoring of groundwater (and other) resources used for public supply. The Unitary Authorities are responsible for monitoring of private water supplies. ............ One of the principal functions of SEPA is to grant consents for discharges to water resources (including groundwater),subject to out relevant to the particular resource, detailed hydrometric surveys and water quality monitoring.

2.16.2.3. Northern Ireland

The groundwater monitoring in Northern Ireland is shared between many institutions. The Environmental Service (ES; Department of Environment/NI) is responsible for the organisation, co-ordination and collation of the data. The original survey work is carried out by the British Geological Survey (BGS) which is a component of the Natural Environment Research Council (NERC). They deliver the data to Water Quality Inspectors, members of Local Councils, that collect and deliver the data to laboratories. Samples are analysed for nitrate in the IRTU, the Industrial Research and Technological Unit (Department of ED/NI). Currently groundwater samples from 5 sites are collected monthly by the Water Quality Inspectors (WQI) and delivered to the Industrial Research and Technological Unit which carries out the nitrate analyses. The results are reported monthly to the Environment Service.

In April 1992 the ES contracted the BGS to undertake a baseline study of the groundwater in Northern Ireland and thereupon a Hydrogeological and a Groundwater Vulnerability Map have been produced. Initially a total of 759 groundwater sources were measured for diameter, depth and statistic water level. At a total 351 sites with either pumped or naturally flowing water: pH, Eh, DO, SEC, temperature, alkalinity and major ions were measured. 109 sites were revisited at 3 monthly intervals until July 1994. These were reduced to 78 target sites and a monitoring contract will be arranged later this year. A BGS report detailing the above information will be available in the near future. In 1992/93 ES contracted ISC (????) to sample and analyse nitrates in 95 groundwaters monthly for 12 month. This monitoring was reduced to 5 sites in October 1993 and sampling will continue until the aforesaid contract is commenced.

2.16.3. Monitoring of Groundwater Quality

2.16.3.1. England and Wales

In the UK the „National Groundwater Quality Monitoring Programme" is a network that provides information for the National Rivers Authority (NRA) which helps to manage the subsurface component of the water resources of England and Wales in a sustainable way, without deterioration in quality. Due to the „Water Resources Act 1991" the NRA has the general duty to monitor „controlled waters". Another legal obligation for water monitoring activities are given in the EC Nitrate Directive and the EC Groundwater Directive. A special interest is given to Nitrate monitoring. The NRA is responsible for programme co-ordination, database management, local sampling, chemical analyses and reporting. It is supported by the Water Service Association which assists in the fields of local sampling and chemical analyses.

In porous media 346 sampling sites are distributed, 270 sites in karst and 1,920 in other groundwater media. Regional current monitoring networks run by NRA have two main types of sampling points, one group for quality monitoring over a wide area and the other for a specific pollution source monitoring covering relatively small areas. These site specific monitoring activities are principally directed at landfills area. Sampling sites greatly vary in their regional distribution. An intended target of the UK`s National Groundwater Monitoring network is to have an average density of 1 site/25 km². The gaps of existing distribution can be filled by using private domestic supply boreholes. Samples are taken from 0.5-4 up to 1-4 times a year. Sample handling procedures depend on the determinants observed. The British Standard provides recommendations for appropriate storage and preservation methods (BS 6068, section 6.3, 1986). Data of regional monitoring activities mostly come from public water supply bodies or are obtained from private or industrial abstraction sources. Springs not used for supply are not seized. The NRA gets the data from the public supply sources due to several regional arrangements made by NRA and the operating companies. The operator mostly takes the local samples and analyses the water and provides the data for the NRA database. Sample analysing procedures have to conform to National Quality Control Standards. At present there is a lack of national uniform quality control and quality assurance procedures. But they will be developed soon.

Data collected are managed by 8 regional databases, which have no common format, plus a unified nitrate database. Over the next 1-2 years the data will migrate to 8 regional databases all using common format and software (WAMS - Water Archive Management System). Data are available on floppy disks, paper sheets and reports at regional NRA offices. Data have to be paid for but they are available without restrictions (except confidential data). The NRA is the reporting organisation, that intends to carry out National Annual Reports in the near future. The target audience is wide, from general public to professionals or governmental organisations.

At present the different regions are busy in improving their network systems to reach the goals of the National Groundwater Monitoring Network in the UK. Its implementation will be approached in a three steps’ development. The monitoring programme should comprise Reference Networks, National Networks and Local Networks. The NRA is mainly responsible for Reference and National Network. Local Networks are run by NRA with other regional or local organisations. The current networks, which often vary in sampling methods, achieving groundwater quality data or have no quality control and assurance procedures, will be improved. The most important improvement concerns the lacks of interpretation and reporting of information on groundwater quality.

A summary of the features of the present and planed monitoring system in the UK is given by the Table S.1 of Technical Report WD/94/40C „Groundwater Quality Assessment: A National Strategy for the NRA, Final Report, November 1994 P J Chilton and C J Milne (British Geological Survey BGS):