Entropy‐based equation to assess hillslope sediment production

Abstract

A new equation to assess hillslope sediment production, based on physical and probabilistic approaches, is presented. The equation, which allows the computation of the delivery ratio for every event, considers the physical variables of travel distance, stream power, settling velocity and gross erosion. The probability density function that arises from the new formulation is solved using the principle of maximum entropy. Based on data from five watersheds in both tropical and temperate zones, the new delivery parameter K v is calibrated and associated with vegetation cover and conservation practice. The proposed equation is rationally based in relation to parameter K v . The entropy-based equation was applied to assess sediment yield in two other experimental watersheds, showing good predictability for the set (mean absolute error of 20·8%). No systematic error was found in the analysed data. The entropy-based equation showed good predictability for long-term sets of data and for higherosivity events, but did not perform well for the low-erosivity ones.

Sediment redistribution due to a dense reservoir network in a large semi-arid Brazilian basin

“…Several investigations have presented empirical approaches relating sediment yield to catchment area, combined, or not, with other factors, such as basin shape, topography, runoff, lithology and vegetation cover (Walling, 1983;Church & Slaymaker, 1989;Verstraeten et al, 2003;de Vente et al, 2005;Minear & Kondolf, 2009). Others have presented distributed or semi-distributed hydro-sedimentological models such as WEPP (Flanagan et al, 1995;Ramsankaram et al, 2009), EUROSEM (Morgan et al, 1998;Mati et al, 2006), SWAT (Chen & Mackay, 2004;Rostamian et al, 2008), HIDROSED (de Araújo & Knight, 2005;de Araújo, 2007), WATEM/SEDEM (Verstraeten et al, 2007;de Vente et al, 2008) and SEDNET (Prosser et al, 2001;Wilkinson et al, 2009), for the assessment of soil erosion and sediment yield at the basin scale. However, none of the above-mentioned empirical approaches and hydro-sedimentological models deals with the HdRN problem, as in the case of large basins of the Brazilian semi-arid region.…”

Comparative hydrology: analysis of a semiarid and a humid tropical watershed

“…It is naturally covered by tropical xerophytic deciduous broadleaf vegetation (caatinga), consisting of a dense mixture of trees, bushes and cacti (Souza and Oliveira, 2003;Mamede, 2008). Further information on the Aiuaba experimental basin can be found in de Araújo (2007). The Cuban humid tropical watershed Jaruco (Figure 1) has a tropical climate with relatively humid summer: 'Aw', according to the Köppen classification system (Piedra, 2001).…”

Assessment of 80 years of ancient‐badlands restoration in Saldaña, Spain

“…These results agree with the litter thickness measurements of Medeiros et al . () for the preserved tropical semiarid‐Aiuaba basin (Brazil) located within an Ecological Station (de Araújo, ). It can be one indicator of the high level of vegetation soil recovery in the Saldaña site.…”

“…Moss is an indicator of very low water flows, because recovering moss crusts need a stable period of more than 14 years (Anderson et al ., ). Moss abundance in all investigated spillways is a sign of low‐energy flow and, therefore, low transport capacity and low erosive potential (Everaert, ; de Araújo, ; Medeiros et al ., ) downstream from the check dams. In the forested hillslope areas, low‐intensity erosive processes cause minor consequences, mainly due to texture and soil structure, to resistance against root penetration and to high slope steepness (Figure ).…”