GEOSCIENCE AND ENVIRONMENTAL SERVICES

Hydrogeological Studies

Aquifer Studies

The MEK hydrogeologists and water specialists have conducted detailed hydrogeological studies in different types of geological terrains worldwide. These studies will usually commence with a comprehensive review of technical literature through the collection, collation and analyses of published and unpublished resources and data availed to our staff. Our staff may undertake additional field studies including geophysical investigations and in borehole drilling to acquire supplementary information that may be required for in-depth understanding of the hydrogeological conditions and for decision making.

Our experiences in this sector include:

  • Delineation and characterization of major aquifers and aquitards;
  • Determination of the major hydrogeological parameters such permeability (hydraulic conductivity)  and transmmissivity of the individual groundwater systems that are relevant for the sustainable planning and management of regional and local aquifer systems and their long-term usage; and
  • Determination of groundwater flow mechanism; preferential flow paths and recharge and discharge areas within a given aquifer system.

MEK has the expertise in simulating different type of aquifers and using the outcome of these studies to properly design wellfields that will stand the test of time; drastically cutting down on operational costs and ensuring the long-term sustainability of the groundwater resource and the producing well(s).

As a team we have conducted and analyzed over 500 pumping and aquifer tests in different hydrogeological terrains. Using these test results, our team members are able to come out with the most efficient well designs and accurately determine the most optimal pumping rates for individual wells. Additionally, our team, through these test analyses, have successfully and accurately inferred relevant aquifer information including the delineation of recharge and discharge areas locally and regional within the groundwater system.

Wellhead Protection Studies

On-going activities within a wellhead protection area have the potential to affect the water quality entering the well and as such the need to delineate the wellhead protection area and take steps to protect it. The major potential sources of contaminants are usually the following:

  • Non-point sources such as spills areas of fertilizers and pesticides;
  • Landfills;
  • Septic tanks and sewerage systems;
  • Underground and above ground storage tanks;
  • Animal feedlots; and
  • Chemical Storage facilities

The areal extent of the wellhead protection area is determined by several factors including the general topography of the land surface, the aquifer type, direction and velocity of groundwater flow; the overlying soil around the well and the water extraction rate, among others.

To ensure the integrity of the aquifer (groundwater body) and prevent its pollution, a Wellhead Protection Plan (WHPP) must be developed. The ultimate goal of protecting the WHPP is to protect public health. In general, the WHPP will reduce the risk of contaminating the groundwater resource and therefore ensuring the long-term supply of potable water. It will also help reduce water treatment costs. MEK has the tools and technical know-how to help accurately delineate the WHPP area. Our team is experienced in using the techniques listed below to accurately delineate WHPP, the capture zone and the contributing areas to the pumping well upon which a WHPP can be based. Over the years our professional staff have used, among others, the following techniques in delineating WHPA:

  • Arbitrary Fixed Radius (AFR) technique;
  • Calculated Fixed Radius (CFR);
  • Analytical Equations;
  • Hydrogeological Mapping; and
  • Numerical Flow Modelling

MEK will be pleased to work with you to delineate your WHPP area and assist you in developing a comprehensive and an effective WHPP plan for your wellhead.

Aquifer Simulation and Modelling

Groundwater models are necessary for understanding the behaviours of groundwater systems in a specific manner and to predict the aquifer behaviour under changing hydrogeological conditions. In the broadest sense a “groundwater model” is the sum of the components, physical or otherwise used to describe a groundwater system. In other words, it is the representation of the construction and working of an aquifer systems of interest. The model will be similar to but simpler than the aquifer systems but a close approximation to the aquifer it represents. On the other hand simulation is a tool to assess the performance of the aquifer under existing, planned or anticipated changing hydrogeological conditions.

MEK generally  uses groundwater models for the following studies:

  • Conceptualization and quantification of hydrogeological conditions of aquifer systems and using the information to plan future data requirements;
  • Exploration of groundwater system dynamics such as surface water-groundwater interactions, recharge areas, seepage rates, transportation dynamics etc.
  • Prediction of changes in aquifer behaviour likely to result from anticipated changes in water abstraction rates;
  • Identification of wellhead protection areas and capture zones;
  • Designing and refining existing monitoring wells networks to better understand the behaviour of the aquifer under changing hydrogeological conditions;
  • Evaluating mitigation options for remediation planning; and
  • As a management tool in the management of complex and extensive aquifer systems.

MEK staff have used analytical, numerical and stochastic models over the years to address numerous challenging groundwater flow and contaminant fate and transport problems in porous and fractured media in different hydrogeological terrains. Our team has developed numerous (finite difference and finite element)  groundwater flow and solute transport models to conducts studies related to leachate movement from landfills, saltwater intrusions, contaminant movement from seepage ponds and movement of pesticides from agricultural fields.

The MEK groundwater modelling team will be pleased to assist you with its expertise to find sound and professional solutions to address your groundwater management problems.

Groundwater Under the Direct Influence of Surface Water

Groundwater is a major source and, in fact, in some areas the only reliable source of potable water. In some areas these aquifers are recharged locally. Therefore they do exhibit characteristics of the surface recharge source and contain surface water contaminants such as various protozoa (crystosporidium and Gardia Lamblia) and bacteria (E. Coli). Such groundwater sources with significant surface water characteristics are referred to as “Groundwater under the Direct Influence of Surface Water” (GUDI). Drinking water wells completed in these aquifers therefore becomes a health risk. Illness, particularly to children and elders may result from drinking water from these wells.

MEK’s accredited professional hydrogeologists are very knowledgeable and have the experience to systematically assess any groundwater system and determine whether it is a GUDI and non-GUDI water system and tailor a suitable solution to address any problem identified during the investigation.

Acid Mine Drainage

Acid Mine Drainage (AMD) is a major problem in mining areas. This is because most of the mineable minerals such as gold, copper, silver etc. naturally occur with sulphide. During mining of these metals, the sulphide bodies become exposed to air and groundwater and under chemical reactions that results in the formation of acidic water which in turn dissolved other harmful metals in the rock. The toxic products resulting from these reactions usually referred to as AMD can run of into surface and even groundwater bodies becoming a hazardous to both aquatic life and humans.

Our team has addressed some interesting AMD problems over the years and fully understand the mechanisms that enhance the process. Our team will carry out systematic investigations to identify the existing sources or any potential source that could initial AMD and provide a timely solution to either forestall the commencement or attenuate AMD on your property.