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  • A PDF File about LID features in InfoSWMM

    • I am having a hard time with the LID swale, I keep getting that error message as well. I tried debugging and thought it might be either the vegetation vol (I put the recommended 0.1) or the swale side slope (2:1)...but that didn't fix the issue.

      I put a trial value in the top width cell as you recommended and finally my error message was gone! Thank you! 

      Would you be able to explain to me what this "Top with of LID" cell actually represents? The help portion isn't giving me a good visual with that description. Are there recommended values?

      I appreciate any help!

      Thank you

      • I have to resort to the code but it needs to the top width to calculate the swale flow fluxes. Here is the section is it used for in LID.C


        void swaleFluxRates(double x[], double f[])
        //
        // Purpose: computes flux rates from a vegetative swale LID.
        // Input: x = vector of storage levels
        // Output: f = vector of flux rates
        //
        {
        double depth; // depth of surface water in swale (ft)
        double topWidth; // top width of full swale (ft)
        double botWidth; // bottom width of swale (ft)
        double length; // length of swale (ft)
        double surfInflow; // inflow rate to swale (cfs)
        double surfWidth; // top width at current water depth (ft)
        double surfArea; // surface area of current water depth (ft2)
        double flowArea; // x-section flow area (ft2)
        double lidArea; // surface area of full swale (ft2)
        double hydRadius; // hydraulic radius for current depth (ft)
        double slope; // slope of swale side wall (run/rise)
        double volume; // swale volume at current water depth (ft3)
        double dVdT; // change in volume w.r.t. time (cfs)
        double dStore; // depression storage depth (ft)
        double xDepth; // depth above depression storage (ft)

        //... get swale's bottom width
        // (0.5 ft minimum to avoid numerical problems)
        slope = theLidProc->surface.sideSlope;
        topWidth = theLidUnit->width;
        topWidth = MAX(topWidth, 0.5);
        botWidth = topWidth - 2.0 * slope * theLidProc->surface.thickness;
        if ( botWidth < 0.5 )
        {
        botWidth = 0.5;
        slope = 0.5 * (topWidth - 0.5) / theLidProc->surface.thickness;
        }

        //... swale's length
        lidArea = theLidUnit->area;
        length = lidArea / topWidth;

        //... top width, surface area and flow area of current ponded depth
        surfWidth = botWidth + 2.0 * slope * depth;
        surfArea = length * surfWidth * theLidProc->surface.voidFrac;
        flowArea = (depth * (botWidth + slope * depth)) *
        theLidProc->surface.voidFrac;

        • Thank you for the quick response! 

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