Ground Water Resources of British Columbia
Chapter 7 — Thermal Springs
by
L.V. Brandon
There are many hundreds of cold springs throughout the Province but those springs which have a water temperature that significantly exceeds the local mean annual air temperature are described as thermal springs. A further subclassification of thermal springs into hot springs refers to those springs with water whose temperature exceeds 32° C (90° F).
Flows from these thermal springs, which are usually found to have water bubbling up through pools or flows of water emerging from rock fractures commonly exceed 10 litres per minute. Many have flows of several hundred litres per minute and the largest springs exceed a thousand litres per minute. At many springs there are several effluent points and it is not uncommon to find tufa or travertine (crystalline forms of calcium and magnesium carbonate) that surround the flow area and create layers of white to brown crystalline mineral deposit. Sometimes the travertine seals off a flow vent and the water then finds another outflow nearby.
More than seventy thermal spring locations have been identified in the Province and it is beyond the scope of this summary to describe the location and hydrogeology of all these. Some springs, such as Harrison, Lakelse, Fairmont and Radiium, have become popular tourist attractions. Many others are well known to local inhabitants, and some are in remote areas and are difficult to find without detailed maps.
Geological reports on most spring localities are available in publications of the Geological Survey of Canada and the British Columbia Mines Branch. One useful summary description has been published by Souther and Halstead (1973), and reference has been made to this in quoting many of the chemical analyses. An interesting book with excellent sketch maps has been prepared by McDonald et al (1978)). This book describes how to obtain access to many remote hot springs and provides good estimates of flow, temperature and other useful background information including ownership and a rating system for scenery and setting. In the decade of the 1970s some studies of geothermal areas were made by B.C. Hydro particularly at Meager Creek west of Lillooet River. Reports on these surveys were made by Nevin and Sadlier Brown (1973) and by Nevin (1975).
For the purposes of this summary, thermal spring regions have been classified into: 1. Northern Rocky Mountain Region. 2. Kootenay and Selkirk Mountain Region. 3. The Coastal Ranges to the Yukon Border. 4. The Islands. In all these regions, the water is of meteoric origin (i.e. precipitation) which has percolated down through rock fractures and fault zones and is emerging from a lower elevation in the ground water flow system.
Heat has been derived from several sources, e.g. from deep circulation, or from the presence at depth of warmer intrusive rocks such as granitic plutons and areas of vulcanism. A third heat source may be from the exothermic reaction of waters of a low pH encountering sulphide minerals; this reaction can generate heat as well as the gas hydrogen sulphide.
Table 7.1 provides some data on over 30 of the known springs and Figure 7.1 is a small map of the Province showing the location of the springs referred to in the table.
Figure 7.1 Thermal springs in British Columbia
Back to Table of Contents
| 
