Bulletin 054

Soil survey of the Calgary urban perimeter

Executive Summary

This report and four 1:50 000 maps include the results of a new soil survey of the Calgary urban perimeter. This resurvey, initiated in 1977, encompasses the region of most active development and expansion around the city of Calgary, from Tp21 to Tp26 and from R27 to R29, W4Mer., and R1 to R5, W5Mer. The results of this study include general information on the kind, characteristics, location, and areal distribution of 33 soil groups and their constituent soil units for agricultural and engineering uses.

This was a level three, semi-detailed soil survey, in which traverses were made at approximately 1.5 to 3 m (1 to 2 mi) intervals or less, with approximately six to ten soil observations taken in every section of land. Aerial photographs and topographic maps at a scale of 1:50 000 were used to establish soil and topographic boundaries.

In general, the Delacour Plain contains the largest extent of Canada Land Inventory class 1 soils, which are capable of sustained production of the full suite of crops common to Alberta. These soils are dominantly Chernozemic with scattered inclusions of Gleysolic and Solonetzic Subgroups. Most are formed on medium-textured till parent materials. Smaller areas have silty Aeolian or sandy glaciofluvial veneers overlying the till materials. The topography is mainly gently undulating and results in few agricultural or engineering limitations.

The Okotoks Benchland and Calgary Laking Basin contain dominantly Canada Land Inventory class 2 soils. A slight reduction in dependable frost free period introduces a climatic limitation to the range of crops that can be successfully cultivated on a sustained basis in these areas. The soils otherwise are generally highly fertile and productive. Almost all are Black Chernozemics with lesser inclusions of Gleysolic soils. The dominant parent materials are very fine textured glaciolacustrine, and moderately fine textured till with some fine textured glaciolacustrine. In the Okotoks Benchland, some steeper, bedrock-controlled slopes restrict both agricultural use and non-agricultural development.

The Big Hill, Broadcast Hill and Leighton Centre uplands contain soils mostly of CLI class 3 or poorer. The cooler climate and shorter frost free period on these upland areas is reflected in the greater extent of aspen vegetation and pasture land relative to cropland. The soils also reflect this change with Dark Grey Luvisols and Dark Gray Chernozems becoming almost as extensive as Orthic Black Chernozems. The landscape is controlled by large, flat-topped, bedrock uplands covered by a thin mantle of moderately fine textured till. Several of the uplands have thick caps of gravel between the bedrock and the till. Steeper topography and, occasionally, shallow depth to bedrock introduce more limitations for agricultural and other development than in the previously discussed areas.

The Priddis Valley is similar to the Calgary Laking Basin but contains mostly CLI class 4 soils or poorer. The soils are mostly fertile, productive Black Chernozems and scattered Gleysolics developed on very fine textured glaciolacustrine parent materials. They are limited principally by a short frost free period. The clayey texture, high moisture storage and lower valley bottom locations combine to create somewhat colder conditions for crop growth. Sloping topography can be limiting for some non-agricultural uses, but it is not generally a problem. The Bow and Elbow valleys cut across a variety of climate zones and contain a variety of soils. Most are rated as CLI class 4 or poorer due to a range of limitations including stoniness, droughtiness, restricted frost free period or steep slopes. Almost all soils are developed on glaciofluvial or glaciolacustrine parent materials of varying thickness that overly rounded valley train gravels on the floor of both valleys. Soil textures range from silty clay slope wash along the edges of the Calgary Laking Basin to sands and gravels closer to the active channel. Slopes are level to gentle except along the steep valley sides.

The Rocky Mountain foothills occupy western portions of the study area and contain most CLI class 5 or 6 soils. These are dominantly Orthic and Dark Gray Luvisols developed on a thin blanket to veneer of moderately fine textured, stony till overlying ridged bedrock. Aspen or spruce vegetation predominates, and the climate is too cool for sustained production of most common crops. Steep topography is a common limitation for many uses, and shallow depth to bedrock can become a constraint for some developments.

Together, mapping and interpretation provide a regional overview of the soil conditions in the Calgary area and a framework for more detailed site investigations and planning. The maps indicate broad soil distribution patterns and combinations of soil likely to be found on specific land parcels. Awareness of the limited extent of high-quality agricultural land and of constraints to both agricultural and non-agricultural uses should assist in improved management in this area.

Place Keywords: 82i; 82j; 82o; 82p; alberta; bow valley; calgary; canada; delacour plain; rocky mountain foothills

Theme Keywords: chernozemic; geology; gleysolic; soil group; soil surveys; solonetzic