Groundwater

Groundwater is protected by the installation of a low permeability clay liner and HDPE liner in the base of the site.  Groundwater varies between 6.2m and 9.8m below the base of the site.

Groundwater is monitored in 16 boreholes strategically installed around the site.  From each borehole on a monthly basis samples are taken and analysed for a wide range of parameters including salts, organic substances and metals.   The Environment Agency set trigger levels for selected parameters and for selected boreholes against which the performance of the site is assessed.

In addition we confirm that the Environment Agency is testing the Horsewater Spring in Kings Cliffe Village, and that they already regularly test other water bodies in the area such as streams and rivers including the Willow Brook and River Nene. Results for the Horsewater Spring can be found at the Parish Council web here .

Below are presented graphs for boreholes with trigger levels for the most recent 12 months of data submitted to the Environment Agency for ammoniacal nitrogen, chloride, cadmium and nickel.  For each graph the reason the parameter has been selected and its meaning are explained above the graph.  The results are discussed below each graph.

Ammoniacal nitrogen
Ammoniacal nitrogen is an indicator of organic contamination.  In combination with elevated chloride it could indicate the presence of landfill leachate.  Elevated levels of ammoniacal nitrogen on its own may indicate an organic source such as agricultural waste or seasonal dieback of vegetation.  A trigger limit of 2.4mg/l is set in the Environmental Permit based on background concentrations in the groundwater.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 The results show that there is little ammoniacal nitrogen in the groundwater and all results are well within the trigger value.

Chloride
Chloride is a good indicator of the presence of salts.  In combination with ammoniacal nitrogen it can indicate the presence of leachate.  Elevated levels of chloride on their own can naturally occur or could be due to contamination from road salt.  A trigger level of 250mg/l is set based on the UK’s Drinking Water Standards.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Down-gradient borehole K14a exhibited slightly elevated chloride concentrations between March 2014 and December 2015, the cause of this increase was traced back to runoff from the site haul road flowing back towards the borehole,  the site have since installed an engineered catchment ditch and lagoon to capture and contain this runoff water and remove it to the on-site treatment facility.  These measures have resulted in a reduction in the chloride concentrations in this borehole to previously observed levels.  The elevated concentrations did not coincide with elevated concentrations of Ammoniacal Nitrogen indicating that the contamination was not a result of landfill leachate.

Cadmium
Cadmium is a heavy metal commonly associated with hazardous waste landfill sites (HPA:2010).  A trigger level of 0.1µg/l is set based on normal detection limits in Environment Agency guidance.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cadmium concentrations have remained stable and within previously observed ranges at the site.

Nickel
Nickel has a trigger limit of 20µg/l as set by the Environment Agency’s Permit for the East Northants Resource Management Facility (ENRMF). This value represents the limit set in the UK Drinking Water Standards. 

 

 

 

 

 

 

 

 

 

 

   


 

 

 

 

There have been no exceedances or elevated concentrations of nickel throughout recent monitoring periods, concentrations have remained stable and within previously observed ranges.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

If you have any queries relating to this information or would like to be kept informed of developments at ENRMF please contact us at consultation@augeanplc.com or telephone us on 01904 654989 to be added to our register of stakeholders.