Topsoil

• Topsoil may be material that was stripped from the project site and stored in stockpiles for re-use, or material imported to the site from a supplier provided the physical and chemical characteristics are within acceptable ranges.
• Topsoil shall be in compliance with Ontario Regulation 153/04 Record of Site Condition standards for soil quality or as amended through Ontario Management of Excess Soil - A Guide for Best Management Practices.
• Soil laboratory reports shall certify the material to be suitable for re-use on residential, parkland, institutional, industrial, commercial, or community landscapes for the germination of seeds and the support of vegetative growth.

The factors to consider in determining a suitable soil mix for a vegetated stormwater practice include the following:

Specify that topsoil must be friable, neither heavy clay nor of a very light sandy nature.

An example of sandy loam topsoil is

• 60 % sand,
• 25 % silt,
• 15 % clay,
• organic matter 5 %, and
• pH value of 6 - 7.5.

Topsoil must be capable of sustaining vigorous plant growth and be free from toxic material and roots, stones or debris over 50 mm in diameter. Specify that samples of topsoil from each source to be drawn upon be provided to the consultant for visual inspection, along with topsoil quality test results from an accredited soil testing laboratory, or a quality assurance certificate from the supplier. We recommend restoring a minimum topsoil depth of 200 mm for planting turf areas, and 400 mm for planting perennials, shrubs and trees.

1. A mineral soil separate consisting of particles less than 0.002 millimeter in equivalent diameter. 2. A soil texture class. 3. (Engineering) A fine-grained soil (more than 50 percent passing the No. 200 Sieve) that has a high plasticity index in relation to the liquid limit. (Unified Soil Classification System).

Mineral particles which are smaller than 2 mm, and which are free of appreciable quantities of clay and silt. Coarse sand usually designates sand grains with particle size between 0.2 and 0.02 mm.

Soil or media particles smaller than sand and larger than clay (3 to 60 m)