Sediment morphology and distribution in a restored riparian forest

Abstract

Sediment distribution patterns of riparian zones reflect the deposition dynamics and the type of deposition event. The purpose of this study is to characterize the morphology and distribution of sediments deposited in a restored riparian forest that were transported from adjacent areas cropped with sugar-cane. In order to study the deposition processes in a riparian forest located in the county of Iracemápolis state of São Paulo, Brazil, soil samples were collected on a transect for micromorphological as well as particle size distribution analyses, using Folk & Ward statistical parameters. Soil samples were dispersed with NaOH + sodium hexametaphosphate and water. The dispersion in water was made to simulate field transport conditions. Particle size distributions together with field and laboratory morphological analyses showed an irregular and non-uniform sediment deposition. This deposition process suggests the occurrence of high intensity erosive events that produce high amount of sediments and runoff characterized by a turbulent flow. The land use change in the riparian area marks the change in the preferential deposition location, which when sugar-cane dominated, corresponded to the alluvial plain and, after the restoration and development of the riparian forest, was dislocated 27 m upslope within the first few meters from the border of the forest.

Sediment Morphology, Distribution, and Recent Transport Dynamics in a Reforested Fragment

“…Thus, soils that exhibit high cohesion generate sediments partially consisting of primary particle aggregates, whereas low cohesion soils tend to produce sediments in the form of primary particles detached by the breakdown of the aggregates during the erosion process (Meyer et al, 1980). Consequently, characterization of the particle size distribution of sediments must be carried out in a way that can measure either the particles dispersed by erosion or the particles transported in the form of aggregates (Momoli et al, 2007). Particle size distribution is also determined using water as a dispersant, as this represents an efficient simulation of the particle dispersion caused by rain or runoff (Meyer et al,1980;Martínez-Mena et al, 1999;Martínez-Mena et al, 2002).…”

“…Sediment deposition may be irregular, uneven, and poorly sorted where the intensity of erosion is high -turbulent flow, but where the intensity of erosion is low -non-turbulent flowdeposition patterns are regular and sediments are well-sorted (Suguio, 1973;Momoli et al, 2007). In order to understand the nature and intensity of the transport processes of detached soil material, statistical analyses of the sand fraction are carried out to quantify the average diameter, degree of sorting, kurtosis, and symmetry of the particle size distribution (Folk and Ward, 1957).…”

Relação entre uso do solo e composição de insetos aquáticos de quatro bacias hidrográficas do Estado de São Paulo

“…Outros impactos causados pela ausên-cia da mata ripária sobre a qualidade do ambiente aquático e também sobre as comunidades que ali vivem são reportados amplamente (Burcher e Benfield, 2006;Paz et al, 2008;Walsh et al, 2005). Dentre os habitantes aquá-ticos, encontram-se plantas, como algas e macrófitas, e animais, como peixes, micro e macroinvertebrados (Momoli et al, 2007;Muotka e Syrjänen, 2007). Dentre estes últimos, destacam-se os insetos aquáticos, que devido à grande diversidade de hábi-tos alimentares, ocupam papel ímpar no ecossistema, por atuarem como elo da cadeia alimentar, e seus requisitos ecológicos lhes conferem o uso como indicadores de qualidade ambiental (MDFRC, 2007;WRC, 2001).…”

Retenção de sedimentos removidos de área de lavoura pela mata ciliar, em Goiatuba (GO)

“…Na presença de matas ciliares, parte dos sedimentos carreados deposita-se sobre o solo original e, assim, formam camadas passiveis de serem identificadas por meio de observações morfológicas ou análises físicas (Filippe, 2006;Santos, 2007;Momoli et al, 2007;Pires et al, 2009;Oliveira, 2010), minimizando, no entanto, os impactos da erosão sobre os recursos hídricos.…”