Vertical Accuracy of Freely Available Global Digital Elevation Models: A Case Study in Karaman Water Reservoir Territory

Nowadays, Uzbekistan pays great attention to the construction of reservoirs for irrigation and energy purposes. Identification of potential sites for the construction of reservoirs and obtaining initial data (the geographical location, storage volume and water surface area, profile of the dam site and others) imposes a great task on project institutes that develop design and survey and pilot work on water engineering. The use of GIS and RS technologies in human life has made it possible to accomplish many tasks quickly, cheaply and accurately. In this research, the main scope of the work is to assess the accuracy of the tested ALOS World 3D - 30m (AW3D30), ASTER GDEM v3, SRTM Plus, COP-30 and NASADEM products for the Karaman water reservoir (recommended for construction in Jizzakh region, Uzbekistan) territory by comparison with 36 Ground elevation points taken from topographic maps (1:25000). Results of statistics values calculated over the geodetic ground elevation points and the DEM data show that NASADEM and AWED30 DEM data are more accurate than other DEMs. The study found that the use of AWED30 and NASADEM data in the design of the proposed Karaman water reservoir for construction leads to a more accurate result. The results obtained using AWED30 data in determining the storage volume (W=780 mln.m3) and area (F=41.4 sq.km) of the water reservoir.