https://community.esri.com/t5/arcgis-pro-questions/flow-accumulation-lines-not-connected/m-p/1243672#M63753 <P>While trying to create a watershed area, I run into the following problem.&nbsp;</P><P>I calculated flow direction &amp; flow accumulation along a topography with clear valleys (red arrows in picture below, with contour lines at 1 m distance spacing and raster at 1x1m resolution).&nbsp;</P><P>Why are my flow lines stopping on the way downhill instead of merging into one larger flow line?</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="flow_accumulation.png" style="width: 999px;"><img src="https://community.esri.com/t5/image/serverpage/image-id/59263i4C2FD5810FE54986/image-size/large?v=v2&amp;px=999" role="button" title="flow_accumulation.png" alt="flow_accumulation.png" /></span></P> Sun, 25 Dec 2022 18:31:21 GMT teakplantation 2022-12-25T18:31:21Z https://community.esri.com/t5/arcgis-pro-questions/flow-accumulation-lines-not-connected/m-p/1243672#M63753 <P>While trying to create a watershed area, I run into the following problem.&nbsp;</P><P>I calculated flow direction &amp; flow accumulation along a topography with clear valleys (red arrows in picture below, with contour lines at 1 m distance spacing and raster at 1x1m resolution).&nbsp;</P><P>Why are my flow lines stopping on the way downhill instead of merging into one larger flow line?</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="flow_accumulation.png" style="width: 999px;"><img src="https://community.esri.com/t5/image/serverpage/image-id/59263i4C2FD5810FE54986/image-size/large?v=v2&amp;px=999" role="button" title="flow_accumulation.png" alt="flow_accumulation.png" /></span></P> Sun, 25 Dec 2022 18:31:21 GMT https://community.esri.com/t5/arcgis-pro-questions/flow-accumulation-lines-not-connected/m-p/1243672#M63753 teakplantation 2022-12-25T18:31:21Z https://community.esri.com/t5/arcgis-pro-questions/flow-accumulation-lines-not-connected/m-p/1243673#M63754 <P>Did you fill depressions to create a proper surface for flow accumuation?</P><P><A href="https://pro.arcgis.com/en/pro-app/latest/tool-reference/spatial-analyst/fill.htm" target="_blank">Fill (Spatial Analyst)—ArcGIS Pro | Documentation</A></P><P><A href="https://pro.arcgis.com/en/pro-app/latest/tool-reference/spatial-analyst/creating-a-depressionless-dem.htm" target="_blank">Creating a depressionless DEM—ArcGIS Pro | Documentation</A></P><P>generally fill your sinks, determine flow direction then flow accumulation</P><P>&nbsp;</P> Sun, 25 Dec 2022 18:40:10 GMT https://community.esri.com/t5/arcgis-pro-questions/flow-accumulation-lines-not-connected/m-p/1243673#M63754 DanPatterson 2022-12-25T18:40:10Z https://community.esri.com/t5/arcgis-pro-questions/flow-accumulation-lines-not-connected/m-p/1243677#M63756 <P>Thanks Dan, spot on!&nbsp;</P><P><span class="lia-inline-image-display-wrapper lia-image-align-inline" image-alt="flow_stream.png" style="width: 999px;"><img src="https://community.esri.com/t5/image/serverpage/image-id/59264i01912707372AF770/image-size/large?v=v2&amp;px=999" role="button" title="flow_stream.png" alt="flow_stream.png" /></span></P><P>&nbsp;</P> Sun, 25 Dec 2022 19:59:56 GMT https://community.esri.com/t5/arcgis-pro-questions/flow-accumulation-lines-not-connected/m-p/1243677#M63756 teakplantation 2022-12-25T19:59:56Z