Groundwater Monitoring
Groundwater monitoring may be required for several reasons:-
- To assess whether groundwater is contaminated – from the site or surrounds
- To determine the hydraulic gradient and therefore direction of groundwater flow
- To provide baseline data – prior to development or as part of an IPPC application
- To monitor the impact of remediation excavations groundwater quality
- To determine the need and method of remedial measures to decontaminate groundwater
Dependent on the site groundwater may be several to tens of metres below the surface. Recovery of samples therefore requires the installation of a monitoring well, which can be excavated through various drilling techniques. The technique chosen is dependent on a range of factors including the anticipated depth, the aquifer status of the site and the nature of the below ground strata.
Having identified suitable locations, the most suitable drilling technique and the required response zone over which monitoring was required, one of our consultants would attend site to oversee the installation of the boreholes. During drilling the profile of the borehole would be logged in accordance with BS5930 and if necessary soil samples collected for analysis.
After a suitable period of settlement our consultants would then undertake a programme of monitoring. Monitoring would include measurement of the depth to groundwater, using a dip meter and recovery of representative water samples. Industry standard process, as stated in Waste Management Paper 4, requires 3-well volumes to be removed from a borehole prior to groundwater sampling. After purging the borehole a sample would be recovered, any required in-situ readings obtained i.e. pH, temperature and then returned to one of our selected accredited laboratories for analysis.
After the results of the in-situ readings and laboratory testing have been collated we would present our findings in a fully interpretative report including an assessment of any contamination identified and where necessary an assessment of its potential risk to surrounding receptors.
At Terragen we can manage all aspects of a groundwater monitoring programme from its formulation and installation through to monitoring and assessment. Should you require any further information or advice, please do not hesitate to contact us at info@terragenenvironmental.co.uk
N.B. It is possible for installations to combine groundwater and gas monitoring facilities.