Factors controlling sediment export in a small agricultural watershed in Navarre (Spain)

Assessing hillslope-channel connectivity in an agricultural catchment using rare-earth oxide tracers and random forests models

“…The climate is humid sub-Mediterranean, with mean annual precipitation of 835 mm, the majority of which falls from October to April (Gobierno de Navarra, 2001). Soils are a silty clay loam, with large, stable aggregates and land use is predominantly agriculture, of which winter wheat is the most abundant crop (Chahor et al, 2014;Giménez et al, 2012). Slopes in the catchment can be steep, up to 30%, but towards the main channel the slope angles decrease to approximately 5-7%.…”

“…Slopes in the catchment can be steep, up to 30%, but towards the main channel the slope angles decrease to approximately 5-7%. Daily hydrological, meteorological and sediment data is available for the period 2002-2015, for details on collection and devices please see Casalí et al (2008Casalí et al ( , 2010; Giménez et al (2012); Chahor et al (2014). Furthermore, a high-resolution (10 cm) digital terrain model of February 2015 was available for the interpretation of flow paths on the hillslope (Masselink et al, 2017).…”

“…Principal component analyses or cluster analyses are often done to analyse factors that influence the hydrological behaviour and the sediment export of a catchment (García-Ruiz et al, 2005;Giménez et al, 2012;Zabaleta et al, 2007). Many of these methods can assess which factors are important for e.g.…”

Dominant mechanisms for the delivery of fine sediment and phosphorus to fluvial networks draining grassland dominated headwater catchments

“…The generation of these sediment dynamics is likely the result of the dominant sediment delivery pathway being a) extensive with a source distal to the main channel (Eder et al, 2010;Marttila and Kløve, 2010), or b) slow-moving (Sadeghi et al, 2008). Given that these dynamics are observed at the outlet station only, during low magnitude events and following relatively dry antecedent conditions, it is highly unlikely that contributing area expansion, the capturing of headwater zones and widespread hydrological connectivity would result in significant contributions from distal 22 sources (Bača, 2008;Giménez et al, 2012;Marttila and Kløve, 2010;Webb and Walling, 1982). Rather, given the event characteristics, sub-surface flow is anticipated to be a significant contributor to both the storm-water discharge and, potentially, the material flux (e.g.…”

Applying profile- and catchment-based mathematical models for evaluating the run-off from a Nordic catchment

“…Catchments having a large contribution of groundwater runoff in the total runoff, in general had lower nitrogen losses. The proportion of the locally detached nutrient load that is transported out of the catchment depends on the magnitude of the local losses, precipitation and antecedent moisture conditions (Giménez et al, 2012), and the degree to which the catchment facilitates water and sediment transport (Heathwaite et al, 2005). The latter term, hydrological connectivity, is itself dependent on structural system components such as terrain, soil physical characteristics and land management, and the system functions that govern drainage and overland flow (Bracken and Croke, 2007).…”