Factors influencing surface runoff generation in a Mediterranean semi-arid environment: Chicamo watershed, SE Spain
✍ Scribed by M. Martínez-Mena; J. Albaladejo; V. M. Castillo
- Publisher
- John Wiley and Sons
- Year
- 1998
- Tongue
- English
- Weight
- 376 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0885-6087
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✦ Synopsis
A deeper knowledge of the hydrological response of semi-arid Mediterranean watersheds would be useful in the prediction of runo production for assessing ¯ood risks and planning ¯ood mitigation works. This study was conducted to identify the runo 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 runo for a three-year period. Two groups of soil were dierentiated with respect to the hydrological response. The ®ne textured, poorly permeable soils of low organic carbon content had a greater runo coecient (9%) and lower runo threshold (3 . 6 mm) than more permeable, coarser textured soils of medium organic carbon content (53%, and 8 mm, respectively). The in¯uence of rainfall characteristics on the hydrological response was dierent. Rain intensity was the major rainfall parameter controlling the runo response in the microcatchments on ®ne textured, low in®ltrability soils with a poor plant cover, while total rainfall was more closely correlated with runo in coarser textured, highly permeable soils with a denser plant cover. It can be concluded that there are two runo generation mechanisms: (i) an in®ltration-excess overland ¯ow in the more degraded areas with low organic carbon content (50 . 5%) and low in®ltrability (45 mm h 71 ); and (ii) a saturation-excess overland ¯ow in the less degraded areas with a high organic carbon content (42%), high in®ltrability (48 mm h 71 ) and covered by a dense plant cover (450%).