Building Site ESC Management
Managing erosion and sediment control during the building phase can be just as challenging as during the development and earthworks phases. Whilst erosion risk may be reduced in some cases due to completed bulk earthworks, flatter grades, and smaller building footprints, this does not eliminate the risk. Active stormwater infrastructure within the street can provide an efficient pathway for sediment and other contaminants to be transported directly to the receiving environment, or to WSUD devices not designed to manage high levels of suspended solids. Additionally, the limited footprint of individual building sites constrains the implementation of effective erosion and sediment controls. When considered cumulatively, these individual sites can represent a significant disturbed area.
Where planning permits, as a priority, consideration should be afforded to maintaining the earthworks phase sediment control well into the building period, or for as long as possible to manage water quality ‘globally’ rather than at the lot scale. However, where or when this is not possible ultimately, the same ESC principles apply for building sites and any other development or infrastructure project, albeit at possibly a reduced level if the building site footprint is small (i.e. less than 1,000m2). In such instances in terms of ‘best practice’ ESC requirements the following control measures should typically be expected:
Coarse sediment barrier (i.e. sediment fence, or similar) along the downslope boundary
Stabilised entry/exit pad (i.e. rock/gravel driveway, or similar) at entry point off street
Stormwater inlet protection for any internal stormwater inlets
Temporary drainage diversion depending on presence of upslope external catchment
Temporary downpipes as soon as roof is installed to divert clean runoff to the street or other outlet location
Retain surrounding soil and grass/vegetation wherever possible outside of the building footprint
Protection of stockpiles to limit loss of material offsite
Waste bin to contain building materials and waste
The above list may sound quite extensive, however most of these measures are very basic and minimal cost. In fact, in terms of material cost to implement the controls listed it is likely to be less than $400, which is significantly less than the potential fines/penalties for non-compliance, not to mention the lost time, cleanup, increased building material loss and poor brand image which badly managed and maintained building sites incur.
Image source – Water by Design