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Factors influencing surface runoff generation in a Mediterranean semi‐arid environment: Chicamo watershed, SE Spain
Author(s) -
MartínezMena M.,
Albaladejo J.,
Castillo V. M.
Publication year - 1998
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/(sici)1099-1085(19980430)12:5<741::aid-hyp622>3.0.co;2-f
Subject(s) - surface runoff , environmental science , hydrology (agriculture) , soil water , infiltration (hvac) , arid , watershed , mediterranean climate , total organic carbon , runoff curve number , flood myth , soil science , geology , ecology , geography , paleontology , geotechnical engineering , archaeology , machine learning , meteorology , computer science , biology
A deeper knowledge of the hydrological response of semi‐arid Mediterranean watersheds would be useful in the prediction of runoff production for assessing flood risks and planning flood mitigation works. This study was conducted to identify the runoff generation mechanisms and their controlling factors at the hillslope scale in a Mediterranean semi‐arid watershed. Four zero‐order microcatchments were selected to measure rainfall and runoff for a three‐year period. Two groups of soil were differentiated with respect to the hydrological response. The fine textured, poorly permeable soils of low organic carbon content had a greater runoff coefficient (9%) and lower runoff threshold (3·6 mm) than more permeable, coarser textured soils of medium organic carbon content (<3%, and 8 mm, respectively). The influence of rainfall characteristics on the hydrological response was different. Rain intensity was the major rainfall parameter controlling the runoff response in the microcatchments on fine textured, low infiltrability soils with a poor plant cover, while total rainfall was more closely correlated with runoff in coarser textured, highly permeable soils with a denser plant cover. It can be concluded that there are two runoff generation mechanisms: (i) an infiltration‐excess overland flow in the more degraded areas with low organic carbon content (<0·5%) and low infiltrability (>5 mm h −1 ); and (ii) a saturation‐excess overland flow in the less degraded areas with a high organic carbon content (>2%), high infiltrability (>8 mm h −1 ) and covered by a dense plant cover (>50%). © 1998 John Wiley & Sons, Ltd.