Common barriers for Local Governments in WA to managing compliance for erosion and sediment control during urban development

28th June, 2019

Pollutants such as soil, sand and cement can be blown or washed away from subdivision, building and construction sites.

Appropriate erosion controls should be used on road work sites and residential, commercial and industrial developments. When appropriate erosion controls are not used, soil, sand and cement travels through the stormwater drainage system and can cause sedimentation of creeks, rivers, marshlands, wetlands and oceans.

Downstream environmental impacts of sedimentation include: reduced light penetration through the water column and therefore a reduced level of photosynthetic activity; detrimental impacts on fish and benthic organism respiration, feeding and reproduction; the creation of breeding grounds for pest and potential disease causing mosquitoes and midges; an increase in nutrient enrichment of waterways and associated algal blooms; change to hydrological functions of waterways; and a decrease in the presence of river pools which provide a vital refuge for fauna during long hot summers and dry seasons.

Effectively preventing sedimentation resulting from urban development is a complex task and often difficult to achieve due to practical and financial limitations. Success requires considerable commitment from the building industry as well as State and Local Governments.

A preventative and proactive approach by Local Government at the planning phase of subdivision and commercial and residential building applications underpinned by strong support at a senior management level and the relevant allocation of financial resources to monitor and enforce compliance is required to effectively address this issue.

In particular, the inclusion of, or reference to, statutory obligations for sediment control when approving residential building plans across the board is necessary. Ongoing on-site education and a greater understanding of legal requirements and of best practice technologies and techniques by land developers and builders is paramount.

Success in Sediment Control will:

  • Reduce the costs to governments and the community for stormwater, river and wetland remediation and management [Read more on the costs]
  • Protect hydrological and biological functions and water quality values, and aesthetic values.
  • Protect our local parks (where storm water is often discharged)
  • Reduce weed infestation of waterways caused by sediment settling on the river bed and transporting nutrients
  • Help conserve our recreational fishing assets; and
  • Reduce sand and sediment build up on roads (increase road and pedestrian safety)


Barriers and difficulties of managing for compliance with erosion and sediment regulations

Achieving compliance can prove problematic for Local Government as determining where sediment has come from is difficult. Local Government can only prosecute when erosion, the dumping of sand or sediment runoff or sand drift is witnessed or when that particular site is the only site under construction in that street or area, which is rarely the case. Determining non-compliance requires Local Government to collect sufficient evidence, such as Officer observations, photographs or video footage which show the origin of the sediment/sand/dust.
Often a lack of resources results in monitoring for compliance being reactionary, which only involves responding to complaints. More proactive monitoring is advantageous, such as regular random scheduled monitoring of sites and the installation of water quality monitoring technologies.

Ensuring compliance is more difficult after subdivision is completed in a large number of cases, as commitments made in site management plans are not well enforced when the various trades enter the site and the site/soil is disturbed by the various earthworks and trades, vehicle manoeuvring, scaffolding and material storage.

Moreover, site space is often limited and undoubtedly challenging for builders to manage all building site materials. Sediment loss is exacerbated by inadequate space for sediment fencing, skip bins and sand stockpiles on site, with the front building setbacks on residential building sites often too small.

Persistent population growth for a number of years has resulted in a very high number of new residential builds through subdivisional works. This has meant that some Local Governments find that the number of builders and developers working in their area is very high and this makes this area complex to regulate, the end result being that often there are far too many non-compliant building sites and far too few resources to adequately manage this issue.

Some Local Governments are in a challenging financial position where rate rises have been minimal or small and their asset base continues to grow each year with gifted roads, drainage, parks, and natural reserves. This can mean they do not have the resources to ensure compliance in regard to preventing soil erosion, sediment runoff and sand drift from building sites.

Local Governments believe infringements can be an effective mechanism for ensuring compliance for smaller sites, if the builder immediately mitigates the poor practice. For larger sites however, the nominal amount of the infringement as compared to the costs of preventing and controlling sediment loss from larger sites confirms that the fine for a breach of the Local Law is not sufficient to act as a deterrent to potential offenders.

In many cases, more stringent controls specific to erosion, sediment runoff and sand drift from urban development are required and there is a requirement for higher fines to act as a disincentive so best practice erosion and sediment control is less dependent on goodwill and voluntary best practice.

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