Abstract. Due to the combined effect of wind and rain, the importance of storm movement to surface flow has long been recognized, at scales ranging from headwater scales to large basins. This study presents the results of laboratory experiments designed to investigate the influence of moving rainfall storms on the dynamics of sediment transport by surface runoff. Experiments were carried out, using a rain simulator and a soil flume. The movement of rainfall was generated by moving the rain simulator at a constant speed in the upstream and downstream directions along the flume. The main objective of the study was to characterize, in laboratory conditions, the distribution of sediment grain-size transported by rainfall-induced overland flow and its temporal evolution. Grain-size distribution of the eroded material is governed by the capacity of flow that transports sediments. Granulometric curves were constructed using conventional hand sieving and a laser diffraction particle size analyser (material below 0.250 mm) for overland flow and sediment deliveries collected at the flume outlet. Surface slope was set at 2%, 7% and 14%. Rainstorms were moved with a constant speed, upslope and downslope, along the flume or were kept static. The results of laboratory experiments show that storm movement, affecting the spatial and temporal distribution of rainfall, has a marked influence on the grain-size characteristics of sediments transported by overland flow. The downstreammoving rainfall storms have higher stream power than do other storm types.

A família Simuliidae é implicada como transmissores das filárias Onchocerca volvulus (Leuckart) e Mansonella ozzardi (Manson) na região norte do Brasil. Os objetivos do presente estudo foram (i) conhecer a fauna de simulídeos em duas comunidades ribeirinhas de Rondônia, (ii) avaliar a abundância e distribuição temporal (mensal e diária) de duas espécies de simulídeos e (iii) avaliar os possíveis efeitos da fatores climáticos na abundância dos simulídeos. As coletas dos simulídeos adultos foram realizadas entre setembro/2008 e dezembro/2009, das 08:00 às 10:00 e das 15:00 às 17:00. A espécie Cerqueirellum pydanieli Pessoa, Medeiros & Barbosa foi a mais abundante em todos os meses e locais. Foi coletado um maior número de indivíduos no período matutino para ambas as espécies (C. pydanieli e Chirostilbia pertinax Kollar) observando-se tendências de alteração nos picos de atividade diária em função da disponibilidade de chuvas. Nessas comunidades foram coletadas 11 espécies de Simuliidae, sendo constatada pela primeira vez, a ocorrência de C. pydanieli, Ectemnaspis rorotaense (Floch & Abonnenc) e Coscaroniellum ulyssesi (Py-Daniel & Coscarón) no estado de Rondônia. Occurrence and Antrhopophily of Simuliid Species in Riverine Communities from Rondônia State, BrazilAbstract. The family Simuliidae is implicated as containing the vectors of human filariid worms (Onchocerca volvulus Leuckart e Mansonella ozzardi Manson) in north region of Brazil. The objectives of this study were (i) to describe the occurrence of black fly species in two riverine communities from Rondônia; (ii) to evaluate the abundance patterns and temporal distribution (monthly and daily) of two blackfly species and (iii) to investigate possible climatic effects in the blackflies abundance. Adult collections were done during September/2008 to December/2009, in the diurnal period, 08:00 to 10:00 AM and 03:00 to 05:00 PM. Cerqueirellum pydanieli Pessoa, Medeiros & Barbosa was the most abundant species during all months, and in both riverine communities. More blackflies were sampled during the morning than afternoon for both species (C. pydanieli and Chirostilbia pertinax Kollar). It was observed a tendency to alteration in the daily activity peaks due to the rainfall period. In these communities were captured 11 Simuliidae species, which provide new records for the state of Rondônia: C. pydanieli, Coscaroniellum ulyssesi (Py-Daniel & Coscarón) and Ectemnaspis rorotaense (Floch & Abonnenc).