Groundwater Quality Monitoring

The WFD groundwater quality monitoring programme is required to:

  • Supplement and validate the Article 5 risk assessment;
  • Help determine the chemical status of groundwater bodies;
  • Establish the presence of significant upward trends in pollutant concentrations and the reversal of such trends when measures are introduced;
  • Support the design and evaluation of programmes of measures.

Surveillance monitoring is required in groundwater bodies that are both "at risk" and "not at risk" of failing the WFD groundwater quality objectives. Generally this network focuses on validating the Article 5 risk assessment, particularly at locations where the degree of uncertainty is greatest. Surveillance monitoring will also be used to detect both natural and anthropogenic trends in water quality.

Operational monitoring is required in groundwater bodies that are "at risk" of failing the WFD groundwater quality objectives. Generally this network focuses on assessing anthropogenically induced upward trends in pollutants and will be used to support the design and provide feedback on the effectiveness of programmes of measures that are introduced to improve water quality in groundwater bodies.

During the first WFD monitoring reporting period, surveillance monitoring will be quarterly and operational monitoring will be monthly. Initial monitoring frequencies are higher where there is inadequate knowledge of the groundwater system or the degree of uncertainty relating to the Article 5 risk assessment is greatest. Once a satisfactory understanding has been achieved, the monitoring frequency may be reduced.


Water Quality Determinands

A standard suite of determinands (Table 1) will be analysed at each monitoring location within the surveillance and operational monitoring networks. This will include:

  • Oxygen content;
  • pH;
  • Conductivity;
  • Nitrate;
  • Ammonium;
  • Major ions;
  • Certain minor ions and metals.

Additional determinands will be analysed on a case-by-case basis for operational monitoring. The pressures identified in the Article 5 Risk Assessment have influenced the selection of these determinands. Determinands will be analysed to detect, as a minimum, concentrations that exceed drinking water quality standards.


Table 1: Water Quality Monitoring Determinands

Monitoring Suite


Standard Suite

pH, Temperature, Conductivity, DO, Colour, Alkalinity, Total Hardness, Nitrate, Ammonium, Nitrite, Total Phosphate, Molybdate Reactive Phosphorus, Iron, Manganese, Sodium, Potassium, Chloride, Calcium, Sulphate, Cadmium, Arsenic, Zinc, Mercury, Lead, Magnesium, Copper, Boron, Aluminium, Nickel, Chromium, Total Organic Carbon, Fluoride, Barium, Molybdenum, Silver, Cobalt, Strontium, Beryllium, Antimony, Turbidity & Uranium

Additional determinands

E-Coli, Total & Faecal Coliforms, Pesticides (Atrazine, MCPA, 2,4-D, IPU, Mecoprop, Chlortoluron, Glyphosate, Bentazone, Cypermethrin, Dieldrin, DDT, Lindane and Diuron); selected VOC's & Hydrocarbons