Groundwater Imaging Geophysics
	Environmental Tracing

These have applications in the minerals, waste management, and water industries and regulatory authorities.

Investigation of Groundwater Resources
The identification of ground water bodies is important at the local and regional scales.  Quarry and landfill operators need to know if groundwater resources may be affected by their operations; farmers and landowners may wish to investigate the possibility off using local groundwater for livestock watering and domestic supply.  The assessment, monitoring and management of groundwater is also important during civil engineering excavations.

The traditional method for determining whether there is useful groundwater is to sink boreholes and carry out pump tests.  Borehole drilling is very expensive and provides only a small 'snapshot' of the potential aquifer.  The borehole may also not be at the optimum location or depth for maximum yield.

Robert Long Consultancy Limited offers a more cost-effective solution to groundwater detection and evaluation using 'electrokinetic geophysical surveying' or EKS.

EKS uses a traditional seismic method coupled to a state-of-the-art amplifier.  This converts very weak electrical responses from water molecules, vibrating in response to seismic shock, into an estimate of aquifer permeability and porosity comparable with estimates from pump tests.

Information can be processed from transects and grids (optimum 25m spacing) to generate 2D and 3D models of the target aquifer, including any pollution plume.


Environmental Tracing
Tracer tests are a valuable tool for carrying out pollution source-pathway-receptor studies.  They can be used to determine a connection between an injection point (e.g. stream sink or injection well) and are thus useful when undertaking groundwater risk assessments.

In conjunction with more detailed monitoring and sampling strategies, tracer tests can also be used to quantify groundwater flow rates and aquifer characteristics such as dilution factors that may affect pollutant attenuation and dispersion.

Our staff and associates are experienced in the use of both natural tracers (e.g. micro-organisms, environmental isotopes, temperature) and artificial tracers (e.g. dyes and their intermediates, salts and other inorganic compounds) to 'label' the waters of interest.

Rhodamine WT injection to STW soakaway system in karstified limestone

Many tracers such as inorganic salts are toxic to fresh water ecosystems in the large quantities usually required.  Our service is focused on the use of fluorescent dyes.  These are the most practical tracers because:

	They are typically non-toxic in the low (sub-visible) concentrations preferred
	Multiple traces are possible in the same catchment using different dyes thereby reducing monitoring and sampling costs

Fluorescein injection to base of 50m deep monitoring well in a limestone quarry

Robert Long Consultancy also provides advice on planning, licensing and technical issues in relation to groundwater monitoring and abstraction wells, and full site investigation and monitoring services.