Integrating ESC with Construction - Opportunities and Myths…
Erosion and sediment control is sometimes considered a hindrance to construction, particularly on constrained sites - it can be seen as something that poses an extra cost that can’t be recovered to the project.
The need to protect the receiving environment from the impacts of construction are generally obvious and not in question. It is now widely appreciated that construction and development activities have the potential to contribute significant loads of sediment and other contaminants into our waterways, resulting in a range of short and long term impacts. It is recognised by some that the importance of undertaking effective ESC management during construction to reduce the sediment loads entering the environment is probably in the order of 10 to 100 times more cost effective than attempting remediation or improvement works afterwards. The question is, how can we get the environmental outcomes we want, without delaying the construction program or making the works unfeasible?
When done well, ESC can and should complement construction activities. During the earthworks period there are typically a number of opportunities to integrate ESC with the site works that achieves environmental compliance, fits within the site constraints, and in (some cases) is actually a billable sum.
Progressively raising the outer perimeter of fill, utilising the earthworks to form a diversion bund;
Utilising internal excavations to satisfy sediment control volume requirements;
Grading formations to drain runoff internally, reducing perimeter drainage controls;
Completing design drainage (particularly diversion drains) during early works. If permanent treatments can’t be completed, the earthworks may be stabilised with temporary scour protection;
Install perimeter bunding, then progressively fill wet, or low-lying areas to retain total runoff capture on site.
Of course there are risks associated with this, particularly where runoff is ponded within earthworks areas. However, with careful planning, including thorough assessment of the earthworks levels and cross-sections, it is certainly possible to effectively integrate an ESC strategy with construction earthworks.
The opportunities vary between specific projects, and may be difficult to find, however we encourage you to ask your planner how!