Watershed and Stream Network Auto-Delineation with ArcGIS by Ariani Andayani

1. Watershed area A watershed can be defined as the area of land that drains to a particular point along a stream. Each stream has its own watershed. Topography is the key element affecting this area of land. The boundary of a watershed is defined by the highest elevations surrounding the stream. A drop of water falling outside of the boundary will drain to another watershed. By Ariani andayani G051060061 Watershed and Stream Network Auto-Delineation with ArcGIS Source: www.dcnr.state.pa.us/brc/rivers/riversconservation/registry/Sewickley_Creek/ watershed def.pdf Objective: - Delineate a watershed area. - Find the streams of the rivers using 3D Analyst

3. 3). Clip data appropiate by available hydrology data boundary with 3D analyst tools  Raster Math  Minus 4). Remove Error Sink in the DEM a. Convert the DEM to integer with Spatial analyst  Raster Calculator b. Remove an error sink with Spatial analyst tool --> Hydrology --> Fill Step 3 Step 4a Step 4b

4. 5). Generate Flow Direction Spatial analyst tool  Hydrology  Flow Direction Step 5

5. 6). Generate Flow Accumulation Spatial analyst tool  Hydrology  Flow Accumulation Step 6

6. Step 7 7). Generating Channel, based on Flow Accumulation Spatial analyst  Raster Calculator ‘ Flow Accumulation >= 500’

7. Step 8 8). Generating Stream Link Spatial analyst tool  Hydrology  Stream Link Use stream chanel and Flow Direction as an input

8. 9). Generating Watershed Spatial analyst tool  Hydrology  Watershed Use Flow Direction and Stream Link as an input Step 9

9. Manual delineation is time consuming Auto delineation is possible by 3D analyst with ArcGIS Error stream network delineation  Flat topography More reasonable  Rough topography Discussion

10. 3D view of study area

11. Watershen and Stream link