But isn’t cleanfill just “lovely, clean topsoil”?

Fill has become a regular sight in Tāmaki Makaurau Auckland. “Fill blindness” is common, or else it is often assumed that cleanfill is “lovely, clean topsoil”. But cleanfill is generally not “lovely, clean topsoil”, and moving it around and dumping it elsewhere can harm the environment, potentially on a large scale. Here are a few reasons why.

Contamination

What is termed “cleanfill” is usually unclean. Cleanfill is officially allowed to contain clay, gravel, sand, soil and rock, as well as a small percentage of human-manufactured materials, such as concrete, brick and tiles, and biodegradable material, for example, vegetation.

Particularly in relation to West Auckland, a horticulture expert informs Friends of Swanson Foothills that the area has a long history of horticulture, including orchards, vineyards, market gardens, berry fruit farms, and grazing. These cropping practices involved the widespread use of soil contaminants such as DDT, dieldrin, arsenic, copper compounds, and lead.

Moving fill from these historic cropping areas (many of which have been cleared for housing development) to other parts of West Auckland is spreading toxic soil contaminants to other areas of West Auckland.

Compaction

Fill is dumped and compacted at illegal dumpsites, killing the soil underneath. An industry expert states that earthworks such as filling, levelling, sculpting, compacting, and the driving of machinery compact the soil so much that the soil loses its pores and no longer acts like a sponge. Rain will slide off the compacted area like a concrete surface during a downpour. This increases runoff and flooding risk.

Soils compacted by fill also suffocate tree roots and stunt tree growth. This reduces the amount of mature tree canopy at a time when the planet continues to heat up.

Domination

An ex-developer has observed the increasing trend over the past decade of developers working less with the land’s natural contours, instead cutting, excavating and levelling the land. This form of development generates a far greater amount of fill to be dumped.