Fill and Aggregate Sites


A 2006 Golder and Blackport Study regarding water quality issues and aggregate sites indicates that it is usually not the extraction process itself, but the post extraction land use applications that has the potential to impact groundwater quality.

LCCW has gathered some important evidence to consider regarding fill quality concerns and the use of former aggregate sites for large fill operations.  The Earthworx Site in Scugog, previously showcased on the MNR website as a model rehabilitation before it was surrendered and filled (link to MNR website), provides one example among several that illustrates the fact that large fill sites can result in the deposition of contaminated fill.

The concern is that more aggregate sites may end up being used as dumping grounds for vast quantities of questionable fill, thereby posing an unacceptable risk to groundwater quality (Work Plan Remedial Soil Excavation Plan – Earthworx Site). The contaminated soil results of a surrendered aggregate pit in the City of Kawartha Lakes legitimize this concern (MOE Letter to the City of Kawartha Lakes re Contamination Issues at fill site -2012).

We also feel there is the potential for the business of commercial fill operations to undermine various meaningful and innovative rehabilitation opportunities for some aggregate sites, opportunities such as those researched in The Ontario Aggregate Resources Corporation, Best Practices Guideline for Aggregate Rehabilitation Projects.

A surrendered aggregate site in East Gwillimbury, operating under a municipal fill permit negotiated on the premise that the fill was needed to rehabilitate the land back to farmland, involved operators filling beyond the areas permitted by their site-plan resulting in a 3 story high mountain of fill being deposited on adjacent farmland. (Neighbour objects to gigantic dirt pile in field – Globe and Mail, 2012)

Besides the examples listed above, below are listed several other examples where overfilling or contamination of “surrendered” aggregate pits has occurred, jeopardizing good rehabilitation practices and potentially impacting groundwater.

  • Brock Aggregate Pit in the Township of Whitby – overfilling- Township report pending.

Additionally, there is an MNR policy regarding salt impacted soils (MNR policy statement – Importation of Inert Fill for the Purpose of Rehabilitation) whereby salt impacted soils testing high in SAR readings can be deposited 1.5 metres below grade so as not to adversely impact plant growth. This policy is currently  being adopted by some large fill sites however, the impact of this policy on groundwater, at MNR aggregate sites as well as large fill sites,  has not yet been determined (E-mail discussion with MNR on impact of salty soils on groundwater). Similarly, the stratified categories in the MOE Tables are for impact on plant growth but do not consider the impact on ground water.

Action Required:
——-Action Items are currently being reviewed and will be posted at a later date.—-

A cursory list is provided here:

1. MNR Review of Aggregate Resources Act to consider fill impacts for soil quality, landform conservation and rehabilitation practices


  • Mandatory incorporation of MOE BMP Guidelines when importing soils for rehabilitation under MNR License
  • Undertake bioregional landscape planning and rehabilitation
  • Mechanisms such as conservation easements for long term protection
  • Uncertainties regarding MOE Table usage, especially concerning importation of salt-impacted soils for rehabilitation purposes, to be addressed