2576 - SBSMP-01 (Feb 2026)

4.5    WBNM Analysis Post-Development, Unmitigated Scenario

Peak flow rates, for the post-development scenario without any intervention measures, were
generated by WBNM to provide a comparison to the pre-development runoff. The table below
shows peak discharge in all storm events for the unmitigated post-development scenario,
including a difference comparison to the pre-development scenario.



                                          DEVELOPED CASE - LPOD1
                                                 Peak Flow Rates - Q (m3/s)
                         AEP             EXISTING       DEVELOPED        Difference
                        63.2%              0.197           0.493          150.3%
                         50%               0.242           0.556          129.8%
                         20%               0.457           0.748            63.7%
                         10%               0.485           0.905            86.6%
                         5%                0.578           1.072            85.5%
                         2%                0.725           1.212            67.2%
                         1%                0.801           1.347            68.2%
             Table 4-5 WBNM discharge flow rates at LPOD1 for the unmitigated post-development scenario


                                          DEVELOPED CASE - LPOD2
                                                 Peak Flow Rates - Q (m3/s)
                         AEP             EXISTING       DEVELOPED        Difference
                        63.2%              0.000           0.012             N/A
                         50%               0.000           0.013             N/A
                         20%               0.000           0.018             N/A
                         10%               0.000           0.024             N/A
                         5%                0.000           0.025             N/A
                         2%                0.000           0.026             N/A
                         1%                0.000           0.029             N/A
             Table 4-6 WBNM discharge flow rates at LPOD2 for the unmitigated post-development scenario


                                        DEVELOPED CASE - COMBINED
                                                 Peak Flow Rates - Q (m3/s)
                         AEP             EXISTING       DEVELOPED        Difference
                        63.2%              0.197           0.504          155.8%
                         50%               0.242           0.569          135.1%
                         20%               0.457           0.766            67.6%
                         10%               0.485           0.929            91.5%
                         5%                0.578           1.097            89.8%
                         2%                0.725           1.239            70.9%
                         1%                0.801           1.376            71.8%
            Table 4-7 WBNM discharge flow rates from the site for the unmitigated post-development scenario




2576-SBSMP-01_Version 1.0 (February 2026)                                                                 Page 18 of 23
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