Monitoring Water Quality on Construction Projects

When delivering construction projects, it is important that we monitor the receiving environment and prevent environmental harm. One of the key receiving environments are waterways. Most major projects cross numerous creeks or rivers and drains. Environmental harm can occur if sediment and other contaminants (such as fuels and chemicals) enter these sensitive environments. To ensure environmental compliance, we need to establish a regular monitoring program, to assess any changes to receiving waterways.

All businesses in Victoria have a duty to manage environmental risks through the General Environmental Duty and comply with the environmental values, indicators and objectives within the Environmental Reference Standard.

Surface Water Sampling

Sampling water and other water bodies is no different than sampling any other media (such as soil) in terms of the fundamentals; developing a monitoring program, sample, analysis and reporting. In most cases, water can be described as either controlled (i.e wastewater or processed water) or uncontrolled (i.e surface water or irrigation water). Each of these require different sampling methodologies to ensure accurate samples are collected and analyte analysis produces reputable measurements from where the sample was taken.

Generally speaking, the purpose of collecting water samples is to obtain chemical and physical attributes of a waterbody for the following reasons:

• Identification of contamination sources to trace origin;
• Regulatory compliance against approval or management plan conditions;
• Assessment of water quality against guidelines, standards or parameter thresholds;
• Rehabilitation or remediation works to improve water quality at a catchment level; and
• Demonstration of environmental due diligence.

Choosing suitable methods and equipment

Choosing the right sampling method is key to ensuring you collect accurate and representable data from a sampling station and water body.

Sampling methods include:

• Collection of a samples by hand;
• Collection by automatic sampler;
• Samplers that collect and integrate samples over a given time;
• Real-time measurement by automatic means;
• Measurements in the field by hand;
• Proximal and remote sensing; and
• Field observation.

Determining which sampling methodology is most appropriate for your application will depend on the parameters to be measured, the information you require from the analysis and the reasons for undertaken sampling. For example, grab samples could be easier to preserve, less liable to contamination or a better size than samples integrated over time (or flow) by automatic devices. In most terrestrial environments, grab samples will be suitable as the waterbody is well mixed, however, offshore or deep-water bodies may require more comprehensive or complex sampling regimes to ensure samples are representative of the environment and parameters being sampled.

Other important aspects that should be considered when selecting your sampling method include:

• Is there a potential for suspended solids to be present?
• Is there a potential for suspended materials or contaminants to be present?
• Is there a potential for separation to occur in the water column?
• Has a fuel or chemical spill occurred nearby?

When selecting and procuring equipment, all methods and equipment used should meet any relevant Australian, New Zealand and International Organisation for Standardisation (ISO) standards and local authority standards (such as EPA Publications).

Sampling Programs

When developing any monitoring programs, Quality Assurance and Quality Control (QA/QC) for field and laboratory measurements must be considered. QA/QC is particularly important when undertaking field sampling, as it is important to ensure site details and observations remain consistent. To assist with the reliability and interpretability of the collected data, appropriate documentation should be integrated into the sampling program so data can be ascribed to the correct location if multiple of sample locations have been established.

Sampling reports should include, as a minimum:

• Positioning of each sample / sample location;
• Description of each site and how to gain access to the sample location;
• Date and time of sampling;
• Method of sampling;
• Weather conditions;?
• Parameters being tested; and
• Delineation of location(s) where the samples were taken.

To find out how Build Enviro can help your company to comply with water quality criteria and other environmental approval conditions, please contact us on (03) 9103 1415 or [email protected].

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