Mapping regional surface water volume variation in reservoirs in northeastern Brazil during 2009–2017 using high-resolution satellite images

Research output: Contribution to journalArticle

Abstract

The multiple-year drought that started in 2011 and reached climax in 2015 was the most severe and prolonged one in the semiarid northeastern (NE) Brazil in recent decades. This study aimed to investigate the reservoir surface water volume (SWV) variation in NE Brazil from 2009 to 2017 in four representative regions covering a total area of approximately 10,000 km2 there and encompassing 2,140 reservoirs (areas range from 0.003 to 21 km2). High-resolution (10 m) digital elevation models (DEMs) were generated from the TanDEM-X data acquired during October–December 2015 to represent the reservoirs' bathymetric maps. The water extents in the reservoirs were delineated from high-resolution (6.5 m) RapidEye images acquired during 2009–2017. The combination of the aforementioned two variables yielded reservoir SWV with an accuracy of 0.64 × 106–1.06 × 106 m3, corresponding to 3.1%–5.6% of the maximum SWV in the reservoirs. The results showed that: 1) 81%–99% of the reservoirs in the four regions were from the groups with maximum water extent <50 ha and contributed 2%–59% of the regional reservoir SWV. In contrast, 0.6%–20% of the reservoirs were from the group of >50 ha and contributed 40%–98% to the regional SWV; 2) From 2009 to 2017, reservoir SWV in the four regions decreased at the rates of 2.3 × 106–17.8 × 106 m3/year; and 3) The SWV in the reservoirs responded differently to the regional terrestrial water budget, i.e. the differences between precipitation and evapotranspiration (P-ET). This study filled the data gap of bathymetric maps for the 2140 reservoirs, regardless of their sizes and macrophyte coverage. The SWV variations derived in those reservoirs over a period covering the recent drought can support better preparedness for drought in NE Brazil and better understanding of the regional hydrology in semi-arid regions.

Details

Authors
  • Shuping Zhang
  • Saskia Foerster
  • Pedro Medeiros
  • José Carlos de Araújo
  • Zheng Duan
  • Axel Bronstert
  • Bjoern Waske
Organisations
External organisations
  • GFZ German Research Centre for Geosciences
  • Uppsala University
  • Federal University of Ceará
  • University of Potsdam
  • University of Osnabrück
  • Federal Institute Of Education, Science And Technology Of Ceará
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Oceanography, Hydrology, Water Resources

Keywords

  • Bathymetric maps, High resolution mapping, NE Brazil, RapidEye, Regional SWV, TanDEM-X
Original languageEnglish
Article number147711
JournalScience of the Total Environment
Volume789
Publication statusPublished - 2021 Oct 1
Publication categoryResearch
Peer-reviewedYes