3.2 GIS ANALYSIS

Purpuse of the exercise    
    •     Discover the ArcGIS software
    •     Experience the basic steps of the software
    •     Conclude some analysis results of each sub-catchment (area, altitude range, lentgh of the drainage line etc.) 
 

Data Processing Process for Watershed Delineation






  • Create new project
  • Add data
  • Fill and Sink
  • Flow Direction 
  • Flow Accumulation
  • Drainage Line 
  • Catchment Grid Delineation
  • Export Catchment 
  • Define Drainage Points
  • Define Final sub-catchment
  
Results

Based on the available DEM for the Var catchment, the drainage network definition and the sub-catchments delineation performed in the previous steps, we obtain general information regarding the morphological characteristics of the catchment. In this way, it has been determined that the total area of the basin is 2833.55 Km2, considered as a large size watershed. It also has a wide range of elevation (and variations in slope), having its highest point at 3045 meter above sea level MSL in the Vésubie sub-catchment in the Alps region, and its lowest in the Var river sub-catchment at almost sea level, near the Mediterranean Sea. The Var catchment also has a very long drainage network with a total length of 253.32 Km. Figure on the right shows a representation of the catchment where topography, sub-catchments and drainage network can be seen. Additional and detailed information of the morphological characteristics of each one of the sub-catchments can be found in Table below.

Comments