SUSPENDED SEDIMENT CONSISTENCY DATA FOR MADEIRA RIVER AT PORTO VELHO, RO, BRAZIL
SUSPENDED SEDIMENT CONSISTENCY DATA FOR MADEIRA RIVER AT PORTO VELHO, RO, BRAZIL
Carvalho, N. O.¹
Marques, F. B. R.¹, Mesquita, J. B. ¹, Strasser, M. A.1, Duarte, U. M.¹, Féres, N. B.¹,
¹ PCE Projetos e Consultoria de Engenharia Ltda, Rio de Janeiro, Brasil
Abstract – This paper covers the consistency of suspended-sediment data for the Madeira River at Porto Velho, period 2003/2007 for feasibility and basic project studies, and 2009/2013, while the construction of Santo Antônio dam located 5.0 km upstream.
The Madeira River, main tributary of the Amazonas, has basin of 1,42x106 km2, occupying 23% of 6,112x106 km2 of the Amazon, and extends through Bolivia, Peru and Brazil. It is named Madeira downstream the confluence of Beni and Mamoré Rivers, flowing 3,600 km from the springs in the Andes. It discharges in the Amazon River 1,300 km upstream the Atlantic Ocean.
Two measurements were done every month, having being reduced to one since 2010. Under operation are six stations in which the same technology of USGS/FISP was accomplished. Besides the samples of suspended and bed materials, it was realized measurements of water discharge by current meters and by ADCP, the latter recently. The sediment analyses are done in appropriate laboratory. The sediment discharge is calculated by the modified Einstein procedure.
Practically all the Madeira sediment load derives from the Andes region due to the metamorphic rocks, high precipitations, great declivities, weak vegetation cover, crescent anthropic actions, etc. Hence, the Madeira River and their tributaries present high sediment loads; on the confluence with the Amazonas River there is an equivalence of amount although it has three times less water discharge.
The consistency analysis was based on double-mass curves, on sediment transport curves, and also on hydrograph values of water discharge Q and sediment discharge Qs, or concentration C. This procedure was considered more suitable than the mathematical analysis due to the small frequency of measurements. The curves presented good adjustment, demonstrating good consistency of the data. It was verified that part of the gross sediment was trapped by the cofferdam, discharging the fine material downstream.
(Very many thanks are extended to Prof. Newton de Oliveira Carvalho, a distinguished expert on sediment research from Brazil, for providing technical documents for sharing within the WASER! )
