Here is an excerpt of one of our studies in Ontario. We were there to protect and understand how significant a site must be to produce a good environment to nurture plant life, and what are the factors.
As part of one of our scientific studies, Part VIII of Ontario Regulation, entitled Site Selection and Construction Standards, sets out the criteria for permanent storage facilities for new or expanded nutrients. To protect our groundwater, Ontario requires that most of these facilities provide two levels of protection, i.e. two physical barriers between stored nutrients and groundwater.
An artificial structure provides one of these barriers. The other can be done by the characteristics of the original soil or by the integration of a coating into the fabric when the first earth does not meet certain standards. To ensure that the site provides adequate protection, the Regulations generally require that a site characterisation study is conducted before the construction or expansion of a permanent nutrient storage facility.
The Regulations define a “permanent nutrient storage facility” as a facility for the storage of materials prescribed by the Regulations (such as manure or stormwater), including an earth storage facility that is a permanent structure or part of such an arrangement. Do not fall within this definition:
permanent solid nutrient storage facilities with a capacity of fewer than 14 days;
permanent liquid nutrient storage facilities with a capacity of fewer than 14 days and a maximum nutrient depth of fewer than 100 millimetres; irrigation or nutrient application systems used to supply liquid fertilisers to crops; permanent nutrient storage facilities used only as part of a vegetative filter strip system.
The Regulations provide for two types of site characterisation studies: a first hydrogeological or geotechnical study of the proposed facility site and a second study. In most cases, the first study is sufficient for the construction or expansion of a storage facility if the location and structure meet specific minimum criteria. A second study, to be conducted by a professional engineer or geoscientist and accepted by the Ministry of Agriculture, Food and Rural Affairs (OMAFRA), may be considered when site conditions do not meet the criteria set out in the Regulations. Because of the scope of the audits to be carried out as part of a second study, it is often very costly.
Many factors can influence the location of a permanent nutrient storage facility and the decision to conduct a site characterisation study. Sections 63 and 67 of the Regulations establish the general criteria for the selection of a site for a permanent nutrient storage facility to be constructed or expanded, which determine whether a site characterisation study is required. These sections take into account location considerations and proximity to wells, subterranean drains and surface water. Most municipalities have by-laws that establish minimum separation distances between manure storage facilities and the various land uses and surrounding residences. The farm configuration may also dictate the location of the permanent nutrient storage facility. It is clear that good communication between all parties involved in the project is essential when choosing the location of the future permanent nutrient storage facility and conducting a site characterisation study.
The site characterisation study should include a record of soil characteristics, including texture, colour and moisture conditions at the time of drilling or excavation. Soil samples for laboratory analysis should also be collected at 1 m intervals and from each horizon encountered where differences in soil materials are noted. Experienced technicians can assess the texture of the soil to the touch by removing a handful of dirt, moistening the ground and feeling it between the push and index finger. Data to be recorded include depth of sampling for each sample, touch assessment of soil texture, depth and characteristics of anomalies observed in the soil, and groundwater table height. Geotechnical consultants generally use standardised records to record information collected in the field.
Soil or geological anomalies are coarse materials that constitute veins or lenses (sedimentary geological formations), movements of bedrock, and roots, rocks or debris of reasonable size that are embedded in the subsoil. If the soil anomaly were to come into contact with the floor or wall of the nutrient storage facility, it could provide a pathway for liquids to flow to the groundwater. Also, if the anomaly includes a porous material, it may cause groundwater to rise to the structure, which would subject it to unexpected hydraulic loads that could lead to structural problems. When site excavation reveals irregularities, the professional engineer or geoscientist must develop a strategy to counter the potential effects of the observed soil or geological conditions.
All soil tests must be performed by an accredited analytical laboratory in Ontario to perform geotechnical analyses of soil samples. A professional engineer or geoscientist should perform the interpretation of all laboratory and field test results.