TY - JOUR A1 - Barbosa, Luis Romero A1 - Almeida, Cristiano das Neves A1 - Rabelo Coelho, Victor Hugo A1 - Freitas, Emerson da Silva A1 - Galvao, Carlos de Oliveira A1 - de Araujo, Jose Carlos T1 - Sub-hourly rainfall patterns by hyetograph type under distinct climate conditions in Northeast of Brazil BT - a comparative inference of their key properties BT - uma inferência comparativa das suas principais propriedades JF - RBRH Revista Brasileira de Recursos Hídricos Brazilian Journal of Water Resources N2 - The lack of process-based classification procedures may lead to unrealistic hyetograph design due to complex oscillation of rainfall depths when assimilated at high temporal resolutions. Four consecutive years of sub-hourly rainfall data were assimilated in three study areas (Guaraira, GEB, Sao Joao do Cariri, CEB, and Aiuaba, AEB) under distinct climates (very hot semi-arid and tropical wet). This study aimed to define rainfall events (for Minimum Inter-event Time, MIT, and Minimum Rainfall Depth, MRD, equal to 30 min and 1.016 mm, respectively), classify their hyetograph types (rectangular, R, unimodal with left-skewed, UL, right-skewed, UR, and centred peaks, UC, bimodal, B, and shapeless, SL), and compare their key rainfall properties (frequency, duration, depth, rate and peak). A rain pulse aggregation process allowed for reshaping SL-events for six different time spans varying from 2 to 30 min. The results revealed that the coastal area held predominantly R-events (64% events and 49% rainfall depth), in western semi-arid prevailed UL-events (57% events and 63% rainfall depth), whereas in eastern semi-arid mostly were R-events (61% events and 30% rainfall depth) similar to coastal area. It is concluded that each cloud formation type had important effects on hyetograph properties, differentiating them even within the same climate. N2 - A falta de procedimentos de classificação baseados em processos pode levar a uma projeção irreal de hietogramas devido à complexa oscilação das lâminas precipitadas quando assimiladas em altas resoluções temporais. Quatro anos consecutivos de dados pluviográficos sub-horários foram assimilados em três áreas de estudo (Guaraíra, GEB, São João do Cariri, CEB, e Aiuaba, AEB) sob climas distintos (semiárido muito quente e tropical úmido). O objetivo deste estudo foi definir os eventos chuvosos (para Tempo Mínimo entre Eventos, MIT, e Altura Mínima de Precipitação, MRD, iguais a 30 min e 1.016 mm, respectivamente), classificar seus tipos de hietograma (retangular, R, unimodal com pico oblíquo à esquerda, UL, oblíquo à direita, UR, e centrado, UC, bimodal, B, e disforme, SL), e comparar suas principais propriedades de precipitação (frequência, duração, altura, taxa e pico). Um processo de agregação de pulsos de precipitação permitiu remodelar os eventos SL para seis períodos de tempo variando de 2 a 30 min. Os resultados revelaram que a área costeira possuía predominantemente eventos R (64% de eventos e 49% de lâmina precipitada), no semiárido ocidental prevaleceram os eventos UL (57% de eventos e 63% de lâmina precipitada), enquanto no semiárido oriental a maioria foram os eventos R (61% de eventos e 30% de lâmina precipitada) semelhante à área costeira. Conclui-se que cada tipo de formação de nuvens teve efeitos importantes sobre as propriedades dos hietogramas, diferenciando-os até dentro do mesmo clima. T2 - Padrões sub-horários da precipitação por tipo de hietograma em condições climáticas distintas no Nordeste do Brasil KW - Rainfall event KW - MIT KW - MRD KW - Hyetograph classification KW - Northeast of Brazil Y1 - 2018 U6 - https://doi.org/10.1590/2318-0331.231820180076 SN - 1414-381X SN - 2318-0331 VL - 23 PB - Associação Brasileira de Recursos Hídricos CY - Porto Alegre ER - TY - JOUR A1 - Mamede, George Leite A1 - Guentner, Andreas A1 - Medeiros, Pedro Henrique Augusto A1 - de Araujo, Jose Carlos A1 - Bronstert, Axel T1 - Modeling the Effect of Multiple Reservoirs on Water and Sediment Dynamics in a Semiarid Catchment in Brazil JF - Journal of Hydrologic Engineering N2 - Taking into account the climatic conditions of the semiarid region of Brazil, with its intermittent rivers and long periods of water scarcity, a dense network of surface reservoirs (on average one dam every 5 km(2)) of very different sizes has been built. The impact of such a network on water and sediment dynamics constitutes a remarkable challenge for hydrologists. The main objective of this work is to present a novel way of simulating water and sediment fluxes through such high-density reservoir networks, which enables the assessment of water and sediment retention in those structures. The new reservoir modeling approach has been coupled with the fully process-oriented and semidistributed hydrological WASA-SED model, which was tailored for semiarid hydroclimatological characteristics. This integrated modeling system was applied to the 933-km(2) Bengue catchment, located in semiarid northeastern Brazil, which has a network of 114 reservoirs with a wide range of surface areas (from 0.003 to 350 ha). The small reservoirs were grouped into size classes according to their storage capacity and a cascade routing scheme was applied to describe the upstream-downstream position of the classes; the large reservoirs were handled explicitly in the reservoir modeling approach. According to the model results, the proposed approach is capable of representing the water and sediment fluxes though the entire reservoir network with reasonable accuracy. In addition, the model shows that the dynamics of water and sediment within the Bengue catchment are strongly impacted by the presence of multiple reservoirs, which are able to retain approximately 21% of the generated runoff and almost 42% of the sediment yield of the catchment for the simulation period, from 2000 to 2012. (C) 2018 American Society of Civil Engineers. KW - Reservoir network KW - Semiarid catchment KW - Sediment retention KW - Water storage dynamic Y1 - 2018 U6 - https://doi.org/10.1061/(ASCE)HE.1943-5584.0001701 SN - 1084-0699 SN - 1943-5584 VL - 23 IS - 12 PB - American Society of Civil Engineers CY - Reston ER -