Hydric Soil Investigation in Assistance of the Master Drainage Plan and Biophysical Impact Assessments for Residential Properties in North Calgary, Alberta, Canada.

A survey of  soils in three proposed residential development areas in Calgary, Alberta, Canada was carried out to characterize areas of imperfectly or poorly drained (hydric) soils and their associated  physical properties, site drainage,  topographic slope position at potential ephemeral wetlands and drainages.  Results were used to inform Biophysical Impact Assessments (BIA), as well as the Master Drainage Plan (MDP). In Alberta, Canada, a hydric soil survey is not required under the Alberta Wetland Policy (2013); however, The City of Calgary requested a hydric soil survey be completed for the proposed developments to identify water bodies qualifying as Environmental Reserve under their Environmental Reserve Setback Policy (2007). In total, 136 soil inspection pits were dug along the soil catena from wetland to upland areas. Hydric soil information was recorded using the criteria outlined in the “Canadian Soil Information System” (Agriculture Canada Expert Committee on Soil Survey 1983), “The Canadian System of Soil Classification” (Soil Working Group 1998) and the “US Army Corps of Engineers Wetlands Delineation Manual” (Environmental Laboratory 1987).  The landscapes were described as high relief undulating to level prairie topography and dominant land use was agriculture (i.e., cropland, cattle grazing). Hydric soils were characterized as Rego and Orthic Humic Gleysols and Gleyed Black Chernozems developed on Glaciolacustrine over Till deposits. The survey found hydric soils in areas delineated as wetlands and ephemeral drainages by previous wetland and hydrology assessments; however, hydric soils were also found in areas outside previously delineated wetlands and ephemeral drainages. In addition, upland (i.e., Orthic Black Chernozems) and transitional (e.g., Gleyed Black Chernozems) soils were found within delineated wetland polygons and identified drainages. Although vegetation and hydrology assessments are important indicators to delineate ephemeral wetlands and drainages, soil surveys should be included in policy for planning urban developments in Alberta.