Properties of Constructed Soils Along Four-Lane Highways in West Virginia

Abstract

Abstract. Four-lane highways have been constructed in West Virginia since the 1960's. During the early construction periods of four-lane highways, geologic information was not assessed, nor was the effect of the disturbance of these geologic materials on soil quality established prior to construction activities. Due to the mountainous topography of the Central Appalachian region, the construction of four-lane highways requires large, expansive cut and fill areas that may contain acid or alkaline producing materials. The disturbance and mixing of these materials with the original soil produces "new" soil that differs considerably from the surrounding native soil. In order to evaluate highway substrate conditions and the development processes of these new soils, study areas along sections of highways have been selected for comparison based on differences in age and geologic parent materials. The long-term goal of this research is to improve selective soil handling of earth excavated during highway construction similar to that of mine overburden materials. Cut, fill and on-grade areas within sections of Interstates 68, 79, and 81 and Corridor H (U.S. Route 33 and State Route 55) have been randomly selected as sampling sites. Soil pits located at 10-m increments along transects perpendicular to these four-lane highways have been sampled at 0-10 cm and 10-20 cm depths and described according to USDA methods. Surface samples also were taken near the edge of the highway. Field pH values of all sites ranged from 5 to 8. Preliminary analysis of the data suggests that thin A horizons develop within 1 to 2 years in rapidly weathering surface materials. In these young soils, little development is observed beneath a weakly developed A horizon, commonly creating an A-C1-C2 or A-AC-C horizon sequence. Soils of intermediate ages (9-12 yrs) were similar to young soils, although at some sites a more developed soil profile was occasionally observed (A-Bw-C1-C2). The most developed soil profiles were observed on sites where soils had been constructed 25 to 43 years ago. At these locations, multiple B horizon sequences were common creating A-Bw1-Bw2-C or A-Bw-BC-C horizons.