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Topographical thresholds for ephemeral gully initiation in intensively cultivated areas of the Mediterranean

dc.contributor.authorVandekerckhove, L.
dc.contributor.authorOostwoud-Wijdenes, D.
dc.contributor.authorFigueiredo, Tomás de
dc.date.accessioned2011-12-22T12:23:23Z
dc.date.available2011-12-22T12:23:23Z
dc.date.issued1998
dc.description.abstractEphemeral gullying is an important erosion process in Mediterranean areas suffering from land degradation because of increased drought and human impact. An ephemeral gully is formed when a hydraulic threshold for incision into a resistant soil surface is exceeded. The flow intensity at the soil surface of any landscape position is controlled by topographical parameters, such as local slope (S) and drainage-basin area (A). The objective of this study was to investigate to what extent one could use field measurements of S and A to predict the location of ephemeral gully initiation in intensively cultivated Mediterranean environments. Two relatively homogeneous study areas in Southeast Spain and Northeast Portugal with widespread ephemeral gullying were selected. S and A were measured by standard methods at the initiation point of 50 ephemeral gullies in each study area. The relationship between S and A was statistically investigated. On a double logarithmic scale, the S and A data showed considerable scatter. Orthogonal regression resulted in the threshold relationship S=aA−b with b=0.133 for Spain, and b=0.226 for Portugal. The analysis also showed that S and A were weakly correlated for the Spanish dataset, and more strongly correlated for the Portuguese dataset. The correlation was considerably strengthened by including additional information on planform curvature and on tillage direction relative to the gully direction. Greater soil stoniness and the presence of a less permeable horizon generally increased the threshold level in both study areas. The threshold relationships resulting from this study were compared with literature data. The indices AcS and ln(Ac/S) were applied to our study sites but neither relationship individually described the general trend between the data of S and A. Therefore, an alternative index, AcbS, with 0.133≤b≤0.226, according to the empirical trend between drainage basin area and local slope, was proposed to describe the topographical threshold conditions for ephemeral gully initiation in similar Mediterranean areas.por
dc.identifier.citationVandekerckhove, L.; Oostwoud-Wijdenes, D.; Figueiredo, Tomás de (1998). Topographical thresholds for ephemeral gully initiation in intensively cultivated areas of the Mediterranean. Catena. ISSN 0341-8162. 33:3-4, p. 271–292por
dc.identifier.doi10.1016/S0341-8162(98)00068-X
dc.identifier.issn0341-8162
dc.identifier.urihttp://hdl.handle.net/10198/6488
dc.language.isoengpor
dc.peerreviewedyespor
dc.publisherElsevierpor
dc.subjectGullypor
dc.subjectSlope gradientpor
dc.subjectDrainage areapor
dc.subjectRock fragmentspor
dc.subjectTillage directionpor
dc.titleTopographical thresholds for ephemeral gully initiation in intensively cultivated areas of the Mediterraneanpor
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage292por
oaire.citation.startPage271por
oaire.citation.titleCATENApor
person.familyNameFigueiredo
person.givenNameTomás d'Aquino
person.identifier1297327
person.identifier.ciencia-id961D-607D-51CC
person.identifier.orcid0000-0001-7690-8996
person.identifier.scopus-author-id54790554500
rcaap.rightsopenAccesspor
rcaap.typearticlepor
relation.isAuthorOfPublicationdb897e48-ecf7-4ce1-ba27-369260337510
relation.isAuthorOfPublication.latestForDiscoverydb897e48-ecf7-4ce1-ba27-369260337510

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