A Terrain Sensitivity Analysis for Trail Development and Impact in the Proposed Grasslands National Park
Forsdick, John Douglas
The proposed Grasslands National Park in southern Saskatchewan represents a unique biophysical environment that will undergo a change in land use consequent upon its establishment as a National Park. Ranching, which is the dominant land use in the area, will be replaced by the development of recreation facilities, including hiking trails, scenic lookouts and interpretive facilities. As a means to determine the impact of trails in this area, a terrain sensitivity study of Core Area A of the proposed park was conducted. Theodore Roosevelt National Park in North Dakota was used as a "yardstick" to determine the environmental effects of trail use, and to develop sensitivity indices for land units. This area has a well developed trail recreation environment in a similar biophysical setting as the proposed Grasslands National Park. As a preliminary step to developing sensitivity indices, each study area was subdivided into land units using genetic and parametric classification techniques. The classification systems depicted particular land units in each study area, each of which has a particular topography, soils, vegetation, wildlife and aesthetic resources. The parametric classification also served to measure and define trail impacts on each land unit's particular components. This information then formed the basis for developing terrain sensitivity indices and impact magnitude and importance evaluations using the Leopold et al (1971) matrix technique. Research results concluded that trail use does have an impact on the grasslands environment; the degree of impact is dependent upon the topography, soils, vegetation and wildlife characteristics of each land unit. In both study areas, south facing slopes were found to be most sensitive to trail use due to unstable slopes and poorly developed soil sand vegetation. The "badland" character of this land unit makes it particularly attractive to recreationists, and thus it will have to be carefully managed to guard against impacts. Dissected uplands are only moderately sensitive due to well developed soils and vegetation which reduce slope instability. Tablelands, the river valley and floodplain will have only minimal to moderate impacts from trail use. The most suitable trail recreation areas are the river floodplains and north facing slopes, both of which have abundant vegetation, relief patterns, wildlife communities and high aesthetic qualities. South facing slopes are too sensitive to sustain intensive trail use, although they are highly attractive. Tablelands and the river valleys are not highly attractive trail areas, except as accesses to recreation nodes (floodplain, river, interpretation areas). The completed study is useful in a number of ways. It provides a comprehensive biophysical resource inventory of the study area; it demonstrates a methodology for establishing terrain sensitivity the sensitivity of land units to trails in the proposed Grasslands indices in a grasslands environment; and it provides a map classifying National Park area. This, then, may be used by planners in the effective design and management of trails.