The current document reports 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.
The approach taken in this document has two main steps:
- Identify sites with no current adverse effects on native grassland ecosystems. This was achieved via application of the criteria in the ESRD Reclamation Criteria for Wellsites and Associated Facilities for Native Grasslands, supported by additional research into the rooting depth of native grassland species.
- Identify sites with no likely future adverse effects on native grassland ecosystems. This was achieved by developing several possible options for determining whether site conditions make future upwards movement of salts from deeper soil horizons into the root zone unlikely. If future upwards movement of salts is unlikely, then future adverse effect on native grassland ecosystems is also unlikely.
Each of the two steps was supported by a compilation of relevant information available in the
literature. The second step was additionally supported by a regional modelling study which
determined an indicator depth for the water table for three representative soil types and for seven
representative locations distributed around the grasslands region of Southern Alberta.