Soil erosion and conservation in two geomorphic and recreational environments

Authors : Deirdre Dragovich

Pages : 67-73

Doi:10.21657/tsd.32964

View : 16 | Download : 12

Publication Date : 2015-01-31

Article Type : Other

Abstract :Erosion in recreational areas is often triggered by vegetation removal as a result of activities like walking, horse-riding, camping, motor vehicle use, mountain bike riding, and development of visitor facilities. Sandy soils in two geomorphic settings were investigated for potential differences in erosion patterns and conservation practices. On a coastal sand dune (100% coarse sand) leading to a popular beach, fencing provided regulated access via rill-eroded, 2 m-wide paths over slopes ranging from 6.5 to 10 degrees and slope lengths from 35 to 45 m. Conservation measures on back-dune paths included repeated spreading of off-site silt/clay-based fill and/or road metal, later replaced by concreting. On the seaward-facing paths where potential erosion rates were estimated to be >10 times those on adjacent vegetated areas, a below-surface board-and-chain system was replaced on some paths by low maintenance solid-surface plastic pavers. In a second area, relic cliff-top dunes were traversed by a 26- km walking track with non-vegetated and unfenced pathway segments 1-3 m wide. Soil texture of the cliff-top dune was dominated by coarse sands (coarse:fine:silt of 91:9:<1 in the study area) which were eroded by wind, water and mass downslope transfer from walkers\' footfalls. Despite gentle slopes (<5 degrees), combined erosion processes resulted in hollowing of pathways below adjacent surfaces to depths of up to 40 cm. Where path surfaces became uncomfortable for walkers, or deep gullies developed, visitors widened paths by trampling adjacent vegetation. This study found that costly installations on eroded pathways are feasible for well-frequented, beach-fringing dunes, but not for lengthy walking tracks with long gentle slopes extending for kilometres; and erosion patterns and conservation measures on sandy soils differ in contrasting geomorphic and recreational environments.
Keywords : Sands, erosion, recreation pathways, conservation.