1. Esri UC 2014 | Technical Workshop | Creating Watersheds, Stream Networks and Hydrologically Conditioned DEMS Steve Kopp Dean Djokic

2. Esri UC 2014 | Technical Workshop | Workshop Overview Data Understanding the tools Advanced workflows Creating Watersheds and Stream Networks

3. Esri UC 2014 | Technical Workshop | Elevation Data Types DEM : Digital Elevation Model “bare Earth” DSM : Digital Surface Model Data Structure Raster TIN Terrain Creating Watersheds and Stream Networks

4. Esri UC 2014 | Technical Workshop | Where do you get DEM data? Sources Global SRTM and HydroSHEDS - 90m ASTER - 30m (challenging for surface runoff modeling) United States NED 30m, 10 m, and higher (ArcGIS Online) LiDAR, IfSAR Generated photogrammetrically Created with interpolation tools especially TopoToRaster Creating Watersheds and Stream Networks

5. Esri UC 2014 | Technical Workshop | DEM Construction Considerations Extent Map Projection (use equal area) Cell size and Resolution Must be appropriate for the landscape and scale being modeled. Source elevation data (accuracy, density, sampling) Interpolation techniques (use TopoToRaster) Special consideration for contour input - TopoToRaster interpolator – works well with contours, creates hydrologically correct DEM Creating Watersheds and Stream Networks

6. Esri UC 2014 | Technical Workshop | Drainage System Watershed (Basin, Catchment, Contributing area) Watershed Boundaries (Drainage Divides) Pour Points (Outlets) Creating Watersheds and Stream Networks

7. Esri UC 2014 | Technical Workshop | Function Processing DEM FLOW DIRECTION SINK FILL FLOWLENGTH FLOW ACCUMULATION WATERSHED SNAP POUR Depressionless DEM Are there any sinks? No Yes STREAM LINE STREAM ORDER STREAM LINK Apply Threshold Creating Watersheds and Stream Networks

8. Esri UC 2014 | Technical Workshop | Hydrologically Correct DEM Sinks Some sinks are real Do not fill in the Great Salt Lake Streams in the correct place? To burn or not to burn Watershed boundaries in the correct place? To fence or not to fence Creating Watersheds and Stream Networks

9. Esri UC 2014 | Technical Workshop | DEM Errors – Sinks and Spikes Sinks: when sinks are (or are not) sinks E.g. Lakes, depressions, karst and glacial landscapes - Global fill - Dealing with internal basins - Selective fill - Depth - Area Sink Filled sink Creating Watersheds and Stream Networks

10. Esri UC 2014 | Technical Workshop | Flow Direction 128 2 22 2 2 2 4 4 4 8 112 1 4 2 8 4 4 8 2 1 2 1 1 1 4 1 4 4 4 16 4 878 74 72 67 69 56 71 49 58 50 69 64 53 58 44 55 37 22 38 31 48 24 68 74 61 53 47 34 21 12 16 11 19 12 46 49 ElevationElevation Direction Coding Flow Direction Creating Watersheds and Stream Networks 64 128 116 82 4 32

11. Esri UC 2014 | Technical Workshop | Flow Accumulation 0 0 0 1 0 1 0 2 0 0 0 0 3 0 7 0 5 20 4 0 0 1 0 0 0 2 0 4 1 7 24 35 0 2 2 0 64 128 116 82 4 32 Direction Coding Creating Watersheds and Stream Networks

12. Esri UC 2014 | Technical Workshop | Function Processing DEM FLOW DIRECTION SINK FILL FLOWLENGTH FLOW ACCUMULATION WATERSHED SNAP POUR Depressionless DEM Are there any sinks? No Yes STREAM LINE STREAM ORDER STREAM LINK Apply Threshold Creating Watersheds and Stream Networks

13. Esri UC 2014 | Technical Workshop | Creating Vector Streams 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 Value = No Data StreamToFeature RasterToFeature Creating Watersheds and Stream Networks

14. Esri UC 2014 | Technical Workshop | Stream Link Assign a unique value to each stream segment. Can be used as input to Watershed tool Creating Watersheds and Stream Networks

15. Esri UC 2014 | Technical Workshop | Stream Ordering Strahler Shreve 3 3 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 4 4 7 7 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 3 3 3 3 Creating Watersheds and Stream Networks

16. Esri UC 2014 | Technical Workshop | Watershed Delineation Identify the contributing area to a cell or group of cells. Creating Watersheds and Stream Networks

17. Esri UC 2014 | Technical Workshop | Snapping Pour Points Use the SnapPour tool to snap the “pour point” of a watershed to the cell of highest flow accumulation within a neighborhood. Prevents accidental creation of tiny watersheds on channel side slopes. Snap distance Cell you clicked on The cell that will be selected (cell with highest flow accumulation) Stream Creating Watersheds and Stream Networks

18. Esri UC 2014 | Technical Workshop | Flow Length Calculate the length of the upstream or downstream flow path from each cell. Creating Watersheds and Stream Networks

19. Esri UC 2014 | Technical Workshop | Where is this functionality? Tools in the Spatial Analyst Toolbox Sample tools, models, and workflows are available in ArcGIS Online Hydro Resource Center resources.arcgis.com/en/communities/hydro Analysis and Geoprocessing Tool Gallery Global Watershed Delineation and Trace Downstream in ArcGIS Online Creating Watersheds and Stream Networks

20. Esri UC 2014 | Technical Workshop | Hosted Hydro Analysis Services (Beta) ArcGIS Online >Living Atlas > Earth > Elevation - Precomputed basins and stream networks - Multiscale Hydro basemap - Watershed Delineation Service - Trace Downstream Service - Profile Service - Elevation Summary Statistics Data processing tools and service scripts will be available on the Hydro Resource Center Creating Watersheds and Stream Networks