EXPANDING AND DISPLAYING THE KARST AREAS PROTECTED IN SOUTH NAHANNI NATIONAL PARK, NORTHWEST TERRITORIES, CANADA

South Nahanni National Park Reserve (Lat. 61^o N, Long. 124-8^o W; ~7000 km²) was created in 1971 to protect three great canyons and a major waterfall from hydroelectric development. In 1978 it was one of the first natural sites to be granted UNESCO World Heritage status, based on the author’s geomorphic analysis. In the course of that work extensive tracts of limestone karst landforms, some of them unique, were explored up to 40 km north of the Reserve boundaries. Following agreements with the First Nations peoples of the region, in 2009 these were incorporated into an expanded park of ~32,000 km² that now includes most of the hydrologic basins of the South Nahanni and of the smaller Ram River north of it.

The case to expand the national park outside of the topographic boundaries of the South Nahanni basin was made in three steps:- (1) a demonstration by fluorescent dye tracing that the underground drainage to major karst springs in S. Nahanni First Canyon extended far to the north of the topographic boundary, the catchment being the southern half of a belt of unique karst terrain that also drained into the Ram basin at its northern extremity: (2) recognition that the headwaters of the Ram River contained an intensely dissected, remnant karst terrain on an anticline that contrasted sharply with (3) a downstream anticline on the same limestone displaying little karst development due to its more recent uplift, and exposure under permafrost conditions. In 2010 a number of ‘hub-and-spoke’ and ‘trekking’ routes for walkers and backpackers are being proposed to display the karst. Potential management problems for these developments include a possible zinc-silver mine to the west that is accessed by a winter road across the karst belt, and accelerating melting of the permafrost in susceptible silts and shales that is creating many new landslides in the karst basins.