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Purpose <p>Increased lake sedimentation is a global concern that threatens the sustainability of lake environments and their associated ecosystem services. Contemporary studies of lake sedimentation using resurvey methods have rarely accounted for the contribution of shoreline sediment. This study aimed to estimate sediment deposition rates and the expected useful lifespan of Lake Tana, the largest lake in Ethiopia, with and without incorporating shoreline sediment contributions.</p> Methods <p>Bathymetric survey data from 2017 and 2023 were used to assess changes in lake volume and estimate sediment deposition rates. Two scenarios were analyzed: one excluding and one including shoreline sediment data derived from remote sensing. Sediment deposition volumes, annual deposition rates, depositional thicknesses, and projected lake lifespans were calculated under both scenarios.</p> Results <p>Between 2017 and 2023, Lake Tana accumulated an estimated 102.20&#xa0;million cubic meters (Mm³) of sediment without shoreline data and 127.38&#xa0;Mm³ with shoreline data, corresponding to annual deposition rates of 20.44 and 25.48&#xa0;Mm³ yr⁻¹, respectively. Inclusion of shoreline data increased the estimated deposition rate by 24.64%. The associated depositional thicknesses were 6.64&#xa0;mm yr⁻¹ (without shoreline data) and 8.28&#xa0;mm yr⁻¹ (with shoreline data). The lake’s projected useful lifespan was 1549 years without shoreline data and 1243 years with shoreline data.</p> Conclusion <p>The results demonstrate that shoreline sediments play an important role in influencing estimates of lake sedimentation rates and lifespans. Incorporating shoreline data enhances the accuracy of sediment budget assessments, underscoring the need for their integration into future studies. Continuous monitoring of sedimentation levels is vital for informed management and sustainable utilization of Lake Tana and similar freshwater resources.</p>

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Improving sedimentation rate estimates by integrating bathymetric surveys with remote sensing: a case study of lake Tana, Northwest Ethiopia

  • 期刊论文

  • 发表日期：

    2026年2月23日

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  • Samuel Berihun Kassa,
  • Atsushi Tsunekawa,
  • Nigussie Haregeweyn,
  • Mitsuru Tsubo,
  • Ayele Almaw Fenta,
  • Dagnachew Aklog,
  • Mulatu Liyew Berihun,
  • Dagnenet Sultan,
  • Taye Minichil Meshesha,
  • Ashebir Sewale Belay,
  • Mebrahtom Gebremariam Kebedew,
  • Takeshi Abe,
  • Yoseph Buta Hailu,
  • Yibeltal Amlak Telake

摘要

Purpose

Increased lake sedimentation is a global concern that threatens the sustainability of lake environments and their associated ecosystem services. Contemporary studies of lake sedimentation using resurvey methods have rarely accounted for the contribution of shoreline sediment. This study aimed to estimate sediment deposition rates and the expected useful lifespan of Lake Tana, the largest lake in Ethiopia, with and without incorporating shoreline sediment contributions.

Methods

Bathymetric survey data from 2017 and 2023 were used to assess changes in lake volume and estimate sediment deposition rates. Two scenarios were analyzed: one excluding and one including shoreline sediment data derived from remote sensing. Sediment deposition volumes, annual deposition rates, depositional thicknesses, and projected lake lifespans were calculated under both scenarios.

Results

Between 2017 and 2023, Lake Tana accumulated an estimated 102.20 million cubic meters (Mm³) of sediment without shoreline data and 127.38 Mm³ with shoreline data, corresponding to annual deposition rates of 20.44 and 25.48 Mm³ yr⁻¹, respectively. Inclusion of shoreline data increased the estimated deposition rate by 24.64%. The associated depositional thicknesses were 6.64 mm yr⁻¹ (without shoreline data) and 8.28 mm yr⁻¹ (with shoreline data). The lake’s projected useful lifespan was 1549 years without shoreline data and 1243 years with shoreline data.

Conclusion

The results demonstrate that shoreline sediments play an important role in influencing estimates of lake sedimentation rates and lifespans. Incorporating shoreline data enhances the accuracy of sediment budget assessments, underscoring the need for their integration into future studies. Continuous monitoring of sedimentation levels is vital for informed management and sustainable utilization of Lake Tana and similar freshwater resources.