Our approach to terrain mapping involves first identifying and analyzing distinctive features and patterns of Earth’s landscapes and landforms that appear in stereo air photos, satellite images and maps.  These interpretations are then used to determine the types, stratigraphy, properties, hazards and physical conditions of soil and rock materials on and below ground surface.  In our daily work we identify, map and assess landforms of all sizes, from mountain ridges and valleys to small landforms the size of gullies and individual meander bends.

The engineers and geoscientists at JDMA have identified, mapped, analyzed and assessed Earth’s diverse terrains for thousands of consulting assignments.  In Canada many of these projects have been in glaciated terrains.  Our expertise in terrain mapping and analysis has been conducted for industry, municipal, provincial and federal governments, national and international engineering and geoscience consulting companies, and universities. Terrain mapping and analysis focus on identifying earth features to infer their origin and evolutionary history, the kinds of soil and rock materials that can be expected in them, and their geotechnical properties and condition.

JDMA staff have extensive experience in mapping, classifying, analyzing and reporting on different types, occurrences and causes of terrain hazards and assessing the risks to existing or proposed infrastructure. Studies start with stereo air photo and LiDAR terrain analysis, and may include 4D (space-and-time) re-construction of geological frameworks and events (where changed conditions are detectable in multi-temporal airphotos and satellite images). Office studies are often followed by field investigations to inspect critical terrain features. One of the more common hazards mapped and assessed are large slope failures and debris flows on steep mountain slopes and in river valleys. Studies include searches for evidence of slope instability along highways, pipelines and railways, at tunnel and bridge sites, on lands in and around cities, and at industrial plants and commercial buildings. Slope instabilities include various types of active and dormant landslides and creep movements, cave-ins from the solution of underlying evaporite beds, and ground subsidence over abandoned underground mines.

The most common slides along major valleys in the three Prairie Provinces are large failures characterized by progressive and episodic creep movements, typically a few centimetres a year, along horizontal bedding planes and bentonite seams in flat-lying overconsolidated bentonitic Cretaceous clay shales. Dormant slides of this nature are easily reactivated from water stored in sag ponds, by river undercutting, and by human excavations at the toe of slides. Hundreds of these shale slides have been mapped and the cause of their failure analysed and described by JDMA staff. In one study, JDMA undertook airphoto mapping of shore conditions in the Qu’Appelle River valley, Saskatchewan, following a major flood that resulted in over a million dollars damage to recreational lands and cottage properties. Most of the damage was located along the shores of the Fishing Lakes, Crooked and Round lakes. At much the same time, active and dormant slides were mapped and described along these same resort lakes, and along both sides of Last Mountain Lake.

Our engineers and geoscientists have identified and analysed various geohazards in mountainous terrain, including rock slumps, debris flows, rockfall and snow avalanches, talus accumulations, and rockslides originating along the top and sides of steep cirque headwalls, where mine sites are proposed in mountainous terrain. Huge rock slides and fault-like sackungen features have been mapped at sites along the Columbia River valley, where large hydro dams and reservoirs have now been built. Some of these slides are still being monitored – for example, Downie Creek Slide and slides along slopes above the Mica Dam reservoir.

In all cases, JDMA combines their expertise in stereo air photo and DEM analysis with the latest available maps and field data to identify and assess potential geohazards and to develop information used for risk assessment, monitoring and mitigation.

In our line of work, understanding the geological setting of a site is vital. Our geologists and earth scientists are experienced in compiling and interpreting geological data obtained from the client and from our own office and field investigations.

The office component of a geological investigation involves gathering and analyzing available data and using remote sensing techniques to infer the surficial material and geological processes at a site. If a valley slope is present, sub-surface material and stratigraphic contact locations can often be inferred as well. We integrate all available data in a GIS, including surficial geology maps, water well and borehole logs in our office investigations.

Our geologists and earth scientists are also experienced in planning and carrying out geological investigations in the field. In past projects, field investigations have involved stratigraphic mapping from exposed cut faces or from borehole drilling and logging, and sampling and analysis of surface material.

Lineaments are linear elements in topography, surface drainage, natural vegetation and soils that are visible as individual and composite lineaments in airphotos, satellite images and shaded-relief maps. Studies by our engineers and geoscientists and other researchers have demonstrated that many remotely sensed lineaments are surficial manifestations of regional systematic fractures and deep-seated faults.

Our engineers and geoscientists have undertaken lineament mapping and data correlation studies in all oil-producing regions of Saskatchewan as well as areas in Alberta and the Northwest Territories. Some of these lineament mapping studies have included the application of near surface soil gas geochemical exploration methods to identify fracture zones along which subsurface gases are venting to surface along interconnected fracture pathways.

We have also mapped lineaments in Saskatchewan and eastern Canada to assess the suitability of bedrock formations for underground carbon sequestration and long-term storage of nuclear waste.

Engineers and geoscientists at JDMA have extensive experience analyzing earth processes and environments to identify landforms, earth materials, hazards and ground conditions for a variety of natural resource and infrastructure development sites. These include sites for hydro dams and reservoirs, coal-fired power plants, industrial minerals development (potash, sodium sulphate), base metal and precious metal mines (gold, diamonds), pulp mills, northern town sites and airstrips, solid and liquid waste disposal sites, First Nations reserves, national parks, hospitals and schools.

Site suitability studies usually begin with stereo air photo recognition and mapping of glacial, fluvial, lacustrine, marine, wind, gravity and bedrock landforms, and with the inferred kinds of earth materials in them and the geological processes and depositional environments that created them. Geologic, topographic (increasingly based on LiDAR data) and soil maps are obtained and interpreted to guide these studies. Sites are usually visited in the field to confirm and help characterize surface conditions, and to recommend follow-up geotechnical or other field investigations.

Dams and reservoirs stand out because of they are often located at sites with complex geological histories, physical environments and materials. Altogether, 52 proposed dam sites have been mapped and assessed from air photos, with most visited in the field by JDMA staff. Dams have subsequently been constructed at many of the studied sites and have been in operation for several decades. Most noteworthy among them are dam and reservoir sites along Canada’s main river systems, including the Columbia, Fraser, Duncan and Iskut systems in British Columbia; the North and South Saskatchewan, Brazeau, Battle, Paddle, Peace, Athabasca, Oldman and Red Deer in Alberta; the North and South Saskatchewan, Churchill and Souris in Saskatchewan; the Churchill and Nelson systems in Manitoba; the Albany and three other large rivers in northern Ontario; the Wreck Cove Brook hydro system of connected lakes in Cape Breton, Nova Scotia; and the Lower Churchill River in Labrador and Newfoundland.

In terms of numbers of sites that have been studied by our engineers and geoscientists, Saskatchewan, First Nation reserves top the list. Most studies were made for aggregate location, housing and transportation infrastructure development on 67 reserves: 43 located in northern Saskatchewan and 24 in southern Saskatchewan.  Many other resource and infrastructure site selection studies for hospitals, schools, transportation systems, town sites and National Park boundaries have been completed by JDMA staff across Canada.