Impact of different parts of unpaved forest roads on runoff and sediment yield in a Mediterranean area.
Surface runoff and sediment production on unpaved forest roads in a humid Mediterranean mountainous area has been studied using a simple portable rainfall simulator at an intensity of 90 mm h(-1). Thirty six rainfall simulations were carried out on road plots: on the roadbank (12), on the sidecast fill (12), and on the roadbed (12). On the roadbanks, the steady-state runoff coefficient was 85.9% and runoff flow appeared after 63 s on average. On the sidecast fills, the steady-state runoff coefficient was 58.6% and mean time to runoff was 48 s. Finally, on the roadbeds, the steady-state runoff coefficient was 21.5% and mean time to runoff was 41 s. The highest soil loss rate was found on the roadbanks (486.7 g m(-2)), mainly due to low plant cover, soil texture and rock fragments. The total soil erosion on the roadbanks was 3 and 18 times higher than those from the roadbeds and the sidecast fills, respectively. As a consequence, roadbanks can be considered the main source of sediments on the studied sites, but the function of unpaved forest roads as source points for runoff generation is more important.
Jordán-López
Antonio
A
MEDSoil Research Group, Dpto. de Cristalografía, Mineralogía y Química Agrícola, Facultad de Química (Universidad de Sevilla), Sevilla, Spain. ajordan@us.es
Martínez-Zavala
Lorena
L
Bellinfante
Nicolás
N
D003198:Computer Simulation; D003247:Conservation of Natural Resources; D017753:Ecosystem; D004777:Environment; D005843:Geography; D019015:Geologic Sediments / Q000032:analysis*; D006813:Humidity; D006863:Hydrogen-Ion Concentration; D019083:Mediterranean Region; D011891:Rain; D012987:Soil / Q000032:analysis*; D013997:Time Factors; D014197:Trees
D012987:Soil