• I found the answer for my own question and would like paste it here if anyone needs it in future.
    The area of a junction is "0".

    Junctions are just connectors which don't have any surface area.
    • If the node is empty the area of a junction is the default area of the junction - the smallest area of a junction is not zero

      • Hi,
        thanks a lot for this clarification.
        I was looking for this and I couldn't find this value.
        I asked from the author of the SWMM 5.0 and I was told that the default value is 0.

        However I now know how to adjust it.

        Thanks again.
        • void initNodeState(int i)
          // Input: i = node index
          // Output: none
          // Purpose: initializes node's surface area, inflow & outflow
          // --- initialize nodal surface area
          if ( AllowPonding )
          Xnode[i].newSurfArea = node_getPondedArea(i, Node[i].newDepth);
          Xnode[i].newSurfArea = node_getSurfArea(i, Node[i].newDepth);
          if ( Xnode[i].newSurfArea < MinSurfAreaFt2 )
          Xnode[i].newSurfArea = MinSurfAreaFt2;

          // --- initialize nodal inflow & outflow
          Node[i].inflow = Node[i].newLatFlow;
          Node[i].outflow = 0.0;
          Xnode[i].sumdqdh = 0.0;

          As you can see above there is a minimum surface area and it is NOT zero - it is normally set by the user or defaults to 12.566 square feet.
          • yeah I understood it. Thanks again for helping me to find out the things.
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