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Effect of Slope and Rainfall Intensity on Erosion from Sodium Dispersed, Compacted Earth Microcatchments
Author(s) -
Evett Steven R.,
Dutt Gordon R.
Publication year - 1985
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1985.03615995004900010040x
Subject(s) - loam , surface runoff , erosion , storm , hydrology (agriculture) , environmental science , universal soil loss equation , intensity (physics) , soil loss , soil science , compaction , geology , geotechnical engineering , soil water , geomorphology , ecology , oceanography , physics , quantum mechanics , biology
Knowledge of erosion in microcatchment systems is needed for the design of water harvesting systems. This study was therefore conducted on the effects of microcatchment slope and length on runoff and erosion rates under natural rainfall. Two replicates of a two factor experimental plot design, including 1, 5, 10 and 15% slopes and 3 and 6 m lengths, were built on a gravelly sandy clay loam using 11.2 Mg/ha of NaCl mixed into the surface 2 to 5 cm of soil followed by compaction with a 6‐Mg roller after a heavy rain. Most of the erosion was from interrill erosion. Length (m) and storm energy, E , (MJ/ha) had no significant effects on erosion. The effects of slope, s , (m/m) and maximum 30 min rainfall intensity, I 30 , (mm/h) were significant at the 0.1% level for the 11 storms studied. These effects were significantly different from those in the USLE (Universal Soil Loss Equation), which underpredicted erosion at low slopes. The best fit equation was A = (0.0595 s 0.998 + 0.0068)I 30 1.86 where A is the estimate of erosion (Mg/ha). The sodium treated surface layer is estimated to last up to 20 yr under our conditions if slopes are kept to 5% or lower on these microcatchments of less than 6m length.