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Evaluation of the Vertical Accuracy of Open Access Digital Elevation Models across Different Physiographic Regions and River Basins of Nepal
  • Saroj Karki,
  • Suchana Acharya,
  • Ashok Gautam
Saroj Karki
Ministry of Physical Infrastructure Development, Province-1, Nepal

Corresponding Author:[email protected]

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Suchana Acharya
Department of Water Resources and Irrigation (DoWRI), Government of Nepal
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Ashok Gautam
Ministry of Physical Infrastructure Development, Karnali Province, Province Government, Nepal
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The vertical accuracy of eight different freely accessible DEMs has been evaluated across different physiographic divisions and the river basins of Nepal. Results revealed that MERIT is superior to other DEMs (RMSE 9m) in the low-lying Terai plains of Nepal where the elevation range is lower. In High mountains and High Himalayas having higher elevation range, SRTM90m outperformed all its counterparts. Meanwhile, in Siwalik and middle mountains, both SRTM90m and HYDROSHEDS exhibited almost similar RMSE indicating their compatible uses in these regions. Meanwhile, the accuracy assessment across different river basins of Nepal discerned that the accuracy of SRTM90m was above others in larger river basins like Koshi (RMSE 224m), Narayani (RMSE 215m), and Karnali (RMSE 265m) where the range of elevation is greater. In the smaller to medium-sized basins like Kankai, Kamala, Bagmati, West Rapti, and Babai, HYDROSHEDS was preferable along with SRTM90m. Based on different error statistics, the DEMs were ranked in order of their accuracy.