Civil engineering projects can have a significant impact on the groundwater environment. Some of these impacts are temporary, while others can introduce more long-term effects.
If we consider the construction of basements, or simple retaining walls on sloping land, there are potential consequences on groundwater systems that can hinder, inhibit, or redirect the flow of groundwater present beneath the surface. While the degree of impact can vary, it emphasises the underlying importance of geotechnical, environmental, and hydrogeological assessment before, during and after the construction work.
In general, civil-construction work can affect groundwater systems in the following ways.
1. Ground settlement (vertical movement of the ground) on nearby structures where groundwater has been permanently or temporarily abstracted (removed).
2. Changes to groundwater levels and flows by new underground structures or flow paths.
3. Changes in groundwater quality such as introduction of rainwater or surface run off into the groundwater table.
Groundwater is an important natural resource that is vital for human and ecological life. Learn more about the importance of groundwater in our related article, Groundwater – why we protect this precious resource.
Importance of groundwater assessment and monitoring
It is important that geotechnical and hydrogeological matters are considered prior to any construction works.
An Environmental Engineer, Environmental Scientist or Hydrogeologist should be engaged to report on constraints and risks to the project and inform strategies to minimise adverse outcomes.
The following key issues should be considered:
- Determine existing groundwater conditions in terms of groundwater levels, such as how levels may fluctuate with climate and tides
- Determine existing groundwater quality to inform options for disposal, treatment or management of abstracted groundwater
- Estimate the volume and rates of groundwater to be dealt for the specific project
- Understand whether there are restrictions on groundwater abstraction, such as licensing requirements
- Develop plans and procedures to manage groundwater during construction and possibly longer term
How Douglas Partners can assist
Groundwater investigation and monitoring
An understanding of regional or local groundwater systems is required for almost any development. The reasons for groundwater investigations vary widely, as do the methodologies and techniques utilised in such investigations.
Our expert team can conduct investigations, often alongside geotechnical/contamination investigation, including:
- Review of relevant information (geological mapping, hydrogeological data from Government databases and review of previous investigations)
- Geophysical surveying
- Drilling and borehole logging
- Monitoring / production well design and installation
- Aquifer and hydraulic testing (test pumping of water bores), and permeability estimation (slug tests)
- Conceptual, analytical, and numerical modelling
- Groundwater quality assessment
- Groundwater impact assessments
The construction of monitoring bores or piezometers allows information on groundwater levels and groundwater quality to be obtained over time. Networks of groundwater monitoring locations are designed to establish baseline (pre-development) conditions, and to record changes (if any occur) over time.
For known groundwater contamination
Prevention, detection, and control requires effective containment and management techniques. Our team can take the following steps to achieve this:
- Site contamination assessment
- Underground storage tank evaluation
- Installation of monitoring wells and groundwater monitoring
- Assessment of contaminant levels
- Design of landfills and tailings dams
- Contaminant transport modelling
- Containment and clean-up strategies
Contact Douglas Partners
Protecting our groundwater resources is becoming ever more important for future generations. Douglas Partner’s Groundwater team can assist clients’ projects in the development, control, and protection of groundwater resources.
