The current document is focussed specifically on issues relating to the ecological direct contact exposure pathway (growth and reproduction of plants and soil invertebrates) in native grasslands areas of Alberta, and develops an Alternate Closure Protocol to identify sites which have no current, and no likely future adverse effects on native grassland ecosystems.
Relevant background data on native grassland ecosystems and on the factors controlling the
movement of moisture and salts in prairie soils was compiled and summarized. A regional moisture
flux modelling study was completed for south eastern Alberta to identify the predicted variation of
water table indicator depth across the region. The term water table indicator depth is used in this
document to reflect a water table depth below which salt accumulation at surface is considered
unlikely.
An alternative closure protocol was developed in this document for salt-affected wellsites in native
grassland habitats in south eastern Alberta. The Alternate Closure Protocol has three main steps:
- Step #1) Demonstrate that the site conditions are having no current adverse effect on the grassland plant community.
- Step #2) Demonstrate that the site conditions are not likely to have an adverse effect on the grassland plant community in the future.
- Step #3) Demonstrate that the site conditions are not likely to have an adverse effect on any other receptors via relevant exposure pathways.