IMPACT OF CLIMATE CHANGE ON FLOW AND SEDIMENT DYNAMICS ON LARGE RIVER BASINS: RIO DOCE BASIN CASE STUDY
Name: Franciélli de Paula Dela Costa
Type: MSc dissertation
Publication date: 13/08/2021
Advisor:
Name |
Role |
|---|---|
| Diogo Costa Buarque | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| Diogo Costa Buarque | Advisor * |
| José Antônio Tosta dos Reis | Internal Examiner * |
| Walter Collischonn | External Examiner * |
Summary: Assessing the effects of climate change on flow and suspended sediments discharge
provides relevant information for the development of water resources management
plans and the elaboration of mitigation and adaptation strategies in river basins. This
study verified the impacts of climate change on the flow and suspended sediments
transport at the Doce river basin, located in the states of Espírito Santo and Minas
Gerais. The basin has high sediment concentrations, which result in one of the highest
sediment loads among large Brazilian basins. For this investigation, the MGB-SED and
the future projections of the RCM Eta-BESM, Eta-CanESM2, Eta-MIROC5 and EtaHadGEM2-ES 20 km were used, with a spatial resolution of 20 km, and of the EtaHadGEM2-ES 05 km, with a spatial resolution of 05 km. Three future periods were
considered for the simulations (2015 - 2040, 2041 - 2070 and 2071 - 2099), carried out
with a daily time step, considering the climate scenarios RCP 4.5 and RCP 8.5.
Simulations with the projections of climate models show a tendency to reduce the
average annual flow and the average annual suspended sediments discharge in the
Doce river basin in the 21st century. However, in some watercourses there may be an
increase in the average annual flows and average annual suspended sediments
discharges generated from the Eta-BESM and Eta-MIROC5 simulations, especially in
the northernmost region of the study area. In the main tributaries and in the basin`s
outlet, the average annual flow trends vary from -5% to -84% in 2015 - 2040, from 0%
to -76% in 2041 - 2070 and from -2% to -91% in 2071 - 2099. The average annual
suspended sediments discharge trends at these points vary from -5% to -91% in 2015
- 2040, from +9% to -82% in 2041 - 2070 and from +12% to -93 % in 2071 - 2099. In
the Suaçuí Grande river basin, positive variations were verified arising from the
simulations with the projections of Eta-MIROC5. The results indicate considerable
differences in the impacts of climate change on average annual flow and average
annual solid discharge as a function of climate models and climate scenarios (RCP).
However, the study carried out shows that all projections indicate that the Doce River
basin may suffer serious problems related to water availability, as well as significant
reductions in the suspended sediments transport. Reductions in sediment transport in
watercourses can significantly affect species habitats and channel erosion. Flow
reductions, on the other hand, can compromise the supply of water for human
consumption and the availability of water for agriculture, industry, electricity generation,
which are important for eastern Minas Gerais and northwestern Espírito Santo
