Regulation 12 Insertion of Schedule
A Schedule shall be inserted into the Groundwater Regulations (Northern Ireland) 2009 as follows:
“SCHEDULE
Groundwater Threshold Values
Regulation 8
Table 1
Threshold values for assessing groundwater chemical status
Parameter Unit To examine if groundwater abstraction is causing saline or other intrusions To examine if groundwater is providing a significant contribution to the failure of the environmental objectives of associated surface water bodies To examine if the quality of groundwater that is abstracted for potable use is deteriorating, possibly resulting in a need for increased purification To examine the spatial extent of a groundwater body or group of bodies that are exceeding an EU Standard or threshold value The surface water environmental standards are set out in Schedule 1 to The Water Framework Directive (Priority Substances and Classification) Regulations (Northern Ireland) 2011(S.R. 2011 No. 10)
The “dilution factor” is taken to be the fraction of the average annual river flow derived from groundwater inflows. It can be estimated from established hydrological indices such as the baseflow index, or from the ratio of catchment groundwater recharge to effective precipitation.
Ammonium mg/l 0.29 Arsenic μg/l 7.5 Atrazine μg/l 0.075 Cadmium μg/l 3.75 Chloride mg/l 25 Electrical Conductivity μS/cm 800 1875 Lead μg/l 18.8 MCPA μg/l 0.075 Mecoprop μg/l 0.075 Mercury μg/l 0.75 Nitrate (as NO3) mg/l
37.5 37.5 Simazine μg/l 0.075 Sulphate mg/l 187.5 Tetrachloroethylene μg/l 7.5 7.5 Trichloroethylene μg/l 7.5 7.5 Any pollutant in relation to which a surface water environmental standard has been setf1 0.5 x (surface water standard divided by dilution factor)f2 Table 2
Threshold values for assessing the risk to wetlands
Column header Annual mean nitrate concentration (mg/l NO3) Altitude Above Ordnance Datum Wetland type up to 175 metres more than 175 metres any Quaking bog 18 4 Wet dune 13 Fen (mesotrophic) and Fen Meadow 22 9 Fen (oligotrophic and wetlands at tufa forming springs) 20 4 Wet grassland 26 9 Wet heath 13 9 Peatbog and woodland on peatbog 9 Wetland directly irrigated by spring or seepage 9 Swamp (mesotrophic) and reedbed 22 Swamp (oligotrophic) 18 Wet woodland 22 9 ”
Annotations
Footnotes
- f1
(1)
The surface water environmental standards are set out in Schedule 1 to The Water Framework Directive (Priority Substances and Classification) Regulations (Northern Ireland) 2011(S.R. 2011 No. 10)
- f2
(2)
The “dilution factor” is taken to be the fraction of the average annual river flow derived from groundwater inflows. It can be estimated from established hydrological indices such as the baseflow index, or from the ratio of catchment groundwater recharge to effective precipitation.